Hi Ziggy - good to see you over here!parts express has other exciters at $17/pair - 1" woice-coil diameter instead of the 3/4" diameter of the $5/pair wersion. and, it has no bypass cap. also, the 1" wersion has built-in 3m adhesive pads, on both the woice-volis and the plastic housing. think this is a worthwhile improvement?
For those of you who want to play, now is the time. Parts express has some buyout exciters for $5 a pair, that's right, five bucks for 2! Won't kill you to get a few. :thumb:
Ziggy is using the 5mm Gatorbaord, which I think is is called 3/16th in the US. It's not cheap, but probably a lot better than foamcore. I was wondering if using a standard 48x96" panel cut in 1/2 might be OK? Not as wide as Ziggy's 28" panel, but close.
The Dayton version is rated at 6 watts rms, but the cheaper one is rated at 10 wrms. The 3/4" dimension relates to front-to-back depth; both are said to have 1" voice coils in the text.it's odd - p/e must have yust changed its info, as now both drivers say:
Since these apparently rely on their own apparently small mass to push the diaphragm to which they're adhered, wouldn't it make sense and increase the efficiency to use some sort of strut down the back like the podium:
http://www.6moons.com/audioreviews/podium2/model05.html
and eliminate (cut off) the spiral plastic legs for less moving mass and better bass response?
I'd be curious to hear how it would sound to make horizontal cuts across the diaphragm to create 7 independent panels in very close proximity, so they would couple acoustically in the bass range and yet not be affected by the vibrations of adjacent transducers.
What makes you say they are real NXT speakers? There have been many other drivers/speakers designed along similar lines over the last 35 years at least, to my knowledge.I mean the Podiums are NXT panels really. By the pictures I see they are not ribbons, electrostatics or magneplanar.
I'd be curious to hear how it would sound to make horizontal cuts across the diaphragm to create 7 independent panels in very close proximity,
what I mean is that all that differentiates NXT from a dozen others is the specific line of what might be called "hype" they use in explaining the virtues of their particular units.
I mean the Podiums are NXT panels really. By the pictures I see they are not ribbons, electrostatics or magneplanar.
I fell the sound should be very good.
Regards.
what I mean is that all that differentiates NXT from a dozen others is the specific line of what might be called "hype" they use in explaining the virtues of their particular units.English is not my native language, but I think you mean hype as a strong, big propaganda ou marketing that may be true or not.
As I read further, a persistent question in my mind is what material qualities lead to a good dml transducer?According earlier on this thread: Alot of exciters and a panel big, light and hard.
This is the link I got from NXT :http://en.billionsound.com.Woww Looks a better exciter than the Dayton, at least by the photo and by the specs: 15Wrms, neodymium, 30mm Dia. 4 ohms huummm...
Look under'' PRODUCTS'' and you will see a picture of a yellow exciter on the right. Click on that to see the range.
This is the link I got from NXT :http://en.billionsound.com.
Look under'' PRODUCTS'' and you will see a picture of a yellow exciter on the right. Click on that to see the range.
Try the regular Site URL here http://www.billionsound.comThis is the link I got from NXT :http://en.billionsound.com.This link doesn't work for me.
Look under'' PRODUCTS'' and you will see a picture of a yellow exciter on the right. Click on that to see the range.
This is all theory at the moment, but I can't see that 4 small areas of adhesion will alter the sound enough to be noticeable......I hope :scratch:Try to position the 4 supporters by the Golden rule! Should be less spurious vibrations.
I still get:Try the regular Site URL here http://www.billionsound.comThis is the link I got from NXT :http://en.billionsound.com.This link doesn't work for me.
Look under'' PRODUCTS'' and you will see a picture of a yellow exciter on the right. Click on that to see the range.
I'm interested. i presume these panels are dipole and so have to be away from rear wall? Also has anyone tried say 10-12 exciters per panel arranged non linierly, on a panel the size of a quad esl57? What sort of base response can one expect in this kind of instance? thanksNXT Panels are bipolar panels!! For this reason I have great interest in this project!! It do not have the usual 5dB of attenuation of the DIPOLES panels, nor need full space around. As I never listen a NXP panel, I will let this detail to ZYGADR inform you.
NXT Panels are bipolar panels!! For this reason I have great interest in this project!! It do not have the usual 5dB of attenuation of the DIPOLES panels, nor need full space around.I can't get my head around the notion of a panel being bipolar and not dipolar, especially in the "lower" frequencies (below about 300 Hz). Can you supply a reference, Fullrangeman?
For me works fine in both address names, I use Explorer 7 and MozilaFireFox 3.2.1NXT Panels are bipolar panels!! For this reason I have great interest in this project!! It do not have the usual 5dB of attenuation of the DIPOLES panels, nor need full space around.I can't get my head around the notion of a panel being bipolar and not dipolar, especially in the "lower" frequencies (below about 300 Hz). Can you supply a reference, Fullrangeman?
Link still doesn't work, by the way - does it for you?
The Dayton DAEX25 Sound Exciter is in stock again at PartsExpress, same price $16,90/16,00 earchwhy not get the cheaper ones?
http://www.parts-express.com/pe/pshowdetl.cfm?Partnumber=300-375
I afraid of cheap products, maybe he feels so. I would like to know what is the best? The dayton or the other white cap exciter? Before buy anything.The Dayton DAEX25 Sound Exciter is in stock again at PartsExpress, same price $16,90/16,00 earchwhy not get the cheaper ones?
http://www.parts-express.com/pe/pshowdetl.cfm?Partnumber=300-375
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=309-148
doug s.
I afraid of cheap products, maybe he feels so. I would like to know whait is the best? The dayton or the other white cap exciter? Before buy anything.The Dayton DAEX25 Sound Exciter is in stock again at PartsExpress, same price $16,90/16,00 earchwhy not get the cheaper ones?
http://www.parts-express.com/pe/pshowdetl.cfm?Partnumber=300-375
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=309-148
doug s.
Regards
Woooooah!!!..........HOLD ON TO YOUR HORSES GENTS!.......a lot of these modelling programs and application documents/patents are for panels that are held firmly or even clamped by all edges, such as hanging picture frames etc.This is the actual NXT original application design notes.
This is totally different to The freely suspended panel like the Podiums and my DIY project.
examples: say you want to run 8 exciters per panel - if you ran two sets of four of the 4-ohm iterations in series, each series would be 16 ohms; when you parallel them, you would end up w/8 ohms total load. do the same w/the 8 ohm iterations, and you would end up w/16 ohms total load.I afraid of cheap products, maybe he feels so. I would like to know whait is the best? The dayton or the other white cap exciter? Before buy anything.The Dayton DAEX25 Sound Exciter is in stock again at PartsExpress, same price $16,90/16,00 earchwhy not get the cheaper ones?
http://www.parts-express.com/pe/pshowdetl.cfm?Partnumber=300-375
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=309-148
doug s.
Regards
In my opinion the cheap ones look just like the ones that Zygadr used. The numbers by the voice coils are similar, but not exact too. The only concern I have about the cheaper ones is that they are 4 ohm, which means a lower amp load if you try to parallel multiples of them together.
Of course I really don't know how much parallel vs. series connections affect sensitivity with this kind of panel driver. Does anyone know if parallel connections increase sensitivity as they do with pistonic drivers sharing a baffle? Also, if you parallel some together, but then have to series connect a couple of paralleled groups together, does that diminish any sensitivity gains you might have gotten from the paralleled exciters?
Hi Fullrangeman, Gatorfoam is a product that has been around for years. Sign companies often use it for displays and signs. I got mine from a company that sells plastics such as coroplast. I believe you could order the exciters from Parts Express. They ship to other countries. I'm in Canada and mine came by mail. Hope this helps. JimThankyou Jim for your help. Could be fine if PartsExpress sell the GatorFoam panels too, I like the Dayton exciters they have.
I wonder what 2 full size 8 foot X 4 Foot panels of Gatorfoam with 12 exciters per side would sound like??? :icon_twisted:.............................JUST KIDDING!! :lol:Dear Zygadr, How is this GatorFoam thing? Could you describe me this material, it already came black? It is hard? It broken? etc...
Zygadr - More good info. Sorry, but what's a BMR?Maybe Basic Membrane Response ??
BALANCED MODE RADIATOR : B.M.R.
My $5 exciters have arrived God they are small! they were out of their boxes all over the large box they came in. are they quite hardy? there's no obvious damage. now for some gatorfoam to buy... this is very interesting! :icon_lol:
So has anyone else been able to get the same results as zygadr. This seems like such an easy project and zygadr has been generously detailed in his instructions so I am surprised not to see many more success stories.
Had an idea for a mounting method for the Gatorfoam...Hi Blob,
The way I see it is that mounting the panels with small foam squares in the corners and 2 on the sides is all that is needed. This works and works well.......very simple, very cheap...and most importantly, does NOT affect or over dampen the panel's resonance at bass frequencies.
With ''voice coil creep'' (voice coil misaligning itself due to the weight of magnet), I have had my panels in the same position for many months now and there has been no audible effects of this.
However, you can see a slight tilt from 90 degrees from the vertical.
Answer...........very simple.........make a panel frame that can be turned upside down twice a year or so. Design it so that the feet of the panel can be removed and mounted at either the top or bottom of the frame :thumb:
Like I've said though........I am yet to hear any negative sonic degradation to this problem if it will ever occur.
I say go for anything that you think will work. But make it reversible should something go wrong.
We are dealing with an unusual technology here, so going to any complexity may be going in the wrong direction - a mistake that has been made by many high end designers in the past.
Let's not forget that :roll:
I'm curious about the function of width with these panels. Common sense tells me that wider would also help give more bass - however common sense also told people the earth was flat. Anybody do any comparisons on what increasing the width of these panels does?Earlie in this thread there is some useful links, that talk about sizes/proportions, I will use one of it (golden ratio 2618=75x196) that is suited for big sizes. These are some links:
* Harmonic dampening characteristicsDear Jeff,
The Harmonic dampening characteristics make we wonder if this is good or bad for a music panel.
I believe that the difference is to do with the spacing between the exciters and how many will fit on a certain sized panel within that ''spacing''.Dear Zygadr:
There is something to this spacing of the exciters. I just don't know what. Podium have the right to keep this information secret, and rightfully so. :?
I wouldn't mind investing in gathering a bunch of materials, if it was clear what the key mechanical properties of the materials were WRT bending waves. Then it's a case of gathering a range and seeing what correlates with the "best" sound.According Zygadr in the past pages, the best material until now is GatorFoam and the best exciter is the Dayton, what I believe.
use fishing line attached to the four corners of the panel(tied through small holes drilled in the corners?) and then tie these to the dowel posts with a few inches of line separating the panel from the posts.
The ends of the posts can be grooved to stop the line from moving about.
On second thought, could they mean 4/9ths of the width and 3/7ths of the height? Sounds unlikely to me, but maybe that's it.This position data are intended for when you are using just one exciter. Why they always think people will use just one exciter with just 6W!!
On second thought, could they mean 4/9ths of the width and 3/7ths of the height? Sounds unlikely to me, but maybe that's it.This position data are intended for when you are using just one exciter. Why they always think people will use just one exciter with just 6W!!
The instructions indicate positions for 1,2,3 and 4 exciters on a panel. Do you know how to interpret them?I think yes, this coordinates are fractions of the width and height of the panel. They not info the width and height of the panel, because this is for you choose.
The instructions indicate positions for 1,2,3 and 4 exciters on a panel. Do you know how to interpret them?I think yes, this coordinates are fractions of the width and height of the panel. They not info the width and height of the panel, because this is for you choose.
Like all exciters will be in the middle vertical of the panel, the first thing you will calc is the distance from the first exciter and then just go ahead, because all exciters are the same distance from each other.
Dayton do not know all exciters must stay in the vertical middle of the panel like the Podium speakers, for this they info two coordinates on this paper. Do you get ?
What is the size of your panel??
How many exciters you will use in each panel??
I have two panels of Gatorfoam, each 4' x 8'. I plan to cut them down, but I have no idea what size is best. Of course, I could use them as is, but my wife wouldn't like it one bit.UHH! You have two full sizes GatorFoam panels!! So if you will cut the panels I can not help in this small panels sizes/exciters.
I have 16 exciters, but I could use less, or buy more, whatever gives optimum results. I plan to experiment a lot.
UHH! You have two full sizes GatorFoam panels!! So if you will cut the panels I can not help in this small panels sizes/exciters.
But if you could use a large panel, I can give you my owns plans for my project.
This is: Panel wide= 75cm, panel High= 196cm (Golden Ratio)
All eight exciters in the vertical middle like the Podium, Final Impedance= 4 ohms, Serie-Parallel (set 1, parallel=8+8+8+8=2ohms, set 2, parallel=8+8+8+8=2ohms, total= 2+2=4ohms)
Exciters Positons, Option ONE= 1? exciter at 21cm from bottom (21, 42 63, 84, 105, 126, 147, 168cm, rest 28cm to top.
Exciters Positons, Option TWO= 1? exciter at 23cm from bottom (23, 46 69, 92, 115, 138, 161, 184cm, rest 12cm to top.
My project for eight exciters this is it!! Anyone fell free to comment...
Dear Henry: Another option: In 1987 I kickout my first wife for want command in my audio hobby.
The reason I ask is that looking at a Chinese manufacturers
website shows a dozen or so 25mm models, but their free air resonance varies between 230 - 500Hz. Are there any specifications on the two models most of us are looking at.
Pardon my ignorance, but what does "free air resonance" mean?
Never mind. I found it.
The other thing I noticed was the white Gatorfoam has superior compression strength, elastic modulus and bending strength for the same weight, compared to black. Probably unimportant , but if colour isn't critical, white may be better.
Interesting. Could you post a link to that information? Thanks.
The description of the "sound bridges" is cryptic. Are they made of a soft marshmallow like material, or is that what glues ithemHi guys,
to the panel? Do they help to hold up the panel, or is it suspended from the spine via the glued on exciters?
"the putty used to seal the speaker wire into the spinal groove", could be replaced with plasticine. "Easy to work with, does not
harden, gentle to the insulation".
Donka, if you haven't already cut it up, how much of the sheet do you have left?Hi folks,
Earlier Fullrangeman mentioned using the golden ratio. It might be interesting to know if a different shape sounds or measures
differently. I think I read that Shelley Katz said the size they chose was determined by the best use / least waste from the nomex
sheets. You never know, that could be far from ideal.
Keen to hear what happens when you test a stand / spline too.
No pressure or anything.
Fullrangeman, isn't the golden ratio 1.618?Yes, it is 3 proportions (1,00 x 1,618 x 2,618). As I want a tall panel I choose 2618. The 1618 size is too square for my personal taste.
Hello, I read about your exciting NXT project I am also thinking on building something like that but how or where did you get the NXT panels ?Dear Eduardo,
Can you share the info ?
Thank you
Has anyone made perfectly square panels? I ask because I figured you could make a full 5 point surround system out of one standard (4x8') gator panel:BYTHEWAY,
Hi Ziggy, did Erling make it around to hear your speakers?Me too!! :drool: Waiting... :drool:
Waiting with bated breath to hear how they compare to the Podiums.
Looking back at the Diyaudio thread, "Greenvalve" suggested that the Dayton exciters were different to the Sonic Impact SoundpadsHi Copperhead,
Ziggy is using. Has anyone got the specs on the Parts Express and Dayton exciters? Do they both have neodymium magnets?
What sensitivity? I saw an exciter claiming 100Hz-20,000KHz. Is this better or worse than the two popular choices? Is greater power
handling an advantage in this application?
So many questions.
One thing I think has been mentioned is using some sort of fishing line to suspend the panel from a frame or other support. I don't remember I've seen any thoughts on how to attach the line to the panel on the least intrisive way. This approach appeals to me because or seems to keep the panel as free as possible while still giving the needed support. Obviously as was mentioned above, this extra step requires some careful aligment, though fishing line is much easier to adjust than wood, foam, etc.
I have a disturbing compulsion that the white piece of foamcore or whatever the sample is that I have here at home is a better material than Gatorfoam.
The reason for this is that the surface seems harder :o......and the foam core is also harder........somehow different and more rigid than Gatorfoam's softish core.
Also see http://tri-dee.com/GatorfoamTechnicalBulletin.htm Info on density and differences between white and natural/black.
Also see http://tri-dee.com/GatorfoamTechnicalBulletin.htm Info on density and differences between white and natural/black.
jonners, I don't know about the accuracy of the specs on the 2 sites but I have found that cutting gatorfoam on a table saw works well. Nice clean cuts, very easy to work with. :D
donka
I am using el cheepo exciters from parts express .I am also using dcx and deq to only monitor the frequency responce, If I can make them sound good without the compensation this would be better.
On 12x24 inch aprox 3 mm ply panel they reach 20k .They are good drivers at a bargain price.
jonners
If you move down the page on that site, they tell you about panel materials to use
donka
DO your panels sound brighter [more hf ] from the back? I am wondering if the hf travels across the surface from the exciter ,but finds it hard to cross the foam to the front surface?
PROBLEMS WITH PANELS
The biggest problems with the sound of these panels is getting used to so much detail. If you have a natural recording in a church, lets say, the sound can be amazing! Astounding!! But if you put on one of your favourite studio recordings, you can end up listening to the studio engineer doing his job, for better or for worse. Sound effects such as echo, phasing, distortions to enhance a voice, are designed to sound acceptable on normal speakers. But on these panels one hears the machine making the sounds, sounds put in and removed - fascinating but Not Good. Consequently, may have to keep old speakers to listen to these recordings.
Sedge,Maybe if you Invert the speaker cable connectors at the amp output may revert the hi freq to the front of the panel/room.
I will say subjectively that the panel does sound brighter on the backside, definitely the one with the sheetmetal insert. Though the increase in HF may be due to boundary reflections.
"Ultrasonics are out of reach, but the midband is utterly transparent and clear."Hi Sedge,
Fullrange,Looks you are right Donka. Nevertheless this made the ELAC material incredible light, just 125 grams per square metre, wish it do not be expensive. (Gatorfoam 4,5mm weight 1120grams per M2). Maybe just is missing a exciter foot in this Elac image...
When I came across that material chart the other day, I figured it must have been a misprint and is instead correctly Kg/m2.
Also I believe I read they suggest glue for mounting, the picture is a little deceiving because they have an integrated suspension/surround surrounding the exciter foot, howver the black plastic surround looks like it pops on/off but you would have to find out if they glue the exciter foot to it upon assembly. As shown you glue/tape the black surround shown I imagine.
My apologies..............as I got you guys very excired about the Elac exciter.ZYGADR
Unfortunately, the product (Imago loudspeaker) was discontinued and is no longer available.
Yet...............the manufacture date on the back of the exciter indicates it was made in 2008 :scratch: ????
With using more than one exciter we are actually using equalisation - for low frequencies we are summing with better efficency (+6dB per doubling of the exciters/ coherent summing) and for the HF with less (+3dB not coherent summing). If useing more than one exciter full range, there might be some destructive interferences for the high frequencies - less hf output.
Due to the dipole radiation at a certain frequency (depending on the size of the panel) a LF drop (-6dB/oct.) starts.
I like your puristic attitude of no filtering just making the thing as straight as possible by the physical arrangement - it's just a question of point of view and finding the right compromises, but I have the strange feeling that running all exciters full range will keep us running in trouble. :banghead:
So, we need to find out exactly what this ''HARDWAX OIL'' is exactly........brand names, equivalents etc.?
If Balsa wood could be joined to make large sheets and dampened/coated it would make a very interesting material.............maybe ideal?
There is an importer for hardwax oil in Australia (this stuff seems to be a german specialty).Hi Boys, nice to see Zygard and others running this thread again.
http://www.whittlewaxes.com.au/Home/Home.asp
Hardwax oil contains carnauba wax, according to Wikipedia the hardest natural wax. It comes from Brazil, same as balsa, so pure canauba might be the alternative for the Fullrangeman, if he can?t get the blend over there.
P.P.S.: I will not buy exciters and panels this year. Iam waiting some honeycomb material and a super exciter, I have no garage to test procedures.Seems there is a new honeycomb candidate, and the manufacturer claims it's inexpensive:
It's my understanding that our panels are bipole not dipole and so a different ball game re cancellation etc.
I'm afraid this is not correct.
In a bipole system, two drivers fire in phase with one another, but in opposite directions.
(http://)
This is not possible with one panel unless it's expanding and contracting in thickness according to the input signal.
Well in fact the panel does contract and expand to some extend - but not in a way so that bipolar behavior is the result.
(http://)
.Pure carnauba could be applied with heat instead of solvent, maybe an advantage.I can be wrong but, apply a kind of oil in the panel will made it no harder, just heavier, as a oil is a heavy liquid.
If you are looking at coating materials for the balsa, you might check out water-base polyurethane. It tends to penetrate less than most other finishes.
If you want something that will penetrate and make the wood harder, there is a product called Wood Hardener, made by a company in the U.S., Minwax. It is formulated to penetrate old rotten wood and set up inside, making it much harder.
I think you may want to glue two thin sheets of balsa together, crossing the grain, so that they will reinforce each other, otherwise you will have a panel that is very flexible along the grain. I don't think you will get the results you want from balsa when it is used in large areas. For one thing, this honeycomb look of the grain is in the wrong direction to give the reinforcement you need. Hard to beat hexagons and triangles for strength, but they need to be perpendicular to the sheet, I think.
One of the problems with balsa is that it will damp out high frequencies like foam. Knock on a block of balsa and you will see what I mean.When I knock on a 500x100x1 mm balsa sheet its sound is somewhere between normal wood and metal. In fact one has to distinguish between the behaviour along the fibers and perpendicular to the fibers. Once I did an experiment with one layer balsa excited by a magnetostatic drive. In the measurement the highs were there, but it sounded what I call foggy, something I also associate with the Podium Sound or paper dual cones. Interestingly with the dayton exciter on three layer balsa this foggyness was not there. But I didn?t do measurements.
Do you think it is possible make a sandwith with PE+balsa+PE??
Sandwiches with a damping balsa middle layer are common. But this is usually end grain balsa (fibers perpendicular to the plate surface). Concerning linearity / neutrality I would prefer aluminium or titanium as cover layers.Alcan have various laminate boards with aluminium, as Alucobond, all ALU board names are aluminum sandwich, but they are all havier than Gatorfoam.
A big gray titanium naked or laminate plate could be great, except for the price.At the Highend in Munich this year I heard the Blumenhofer Fun 17 and I really liked it. Later I discovered by googling that it uses a carbon fiber / polymer sandwich cone which is very well-damped and suitable for simple crossover. Strangely this speaker has a very open sound, no comparison to the muffled sound of polypropylene, bextrene or the polymer mix used by Harbeth. Here is the stuff:
Could be a hot candidate for laminating on titanium. BTW, what do these titanium sheets cost? Are they more expensive than aramide honeycomb?By what I know TI is very expensive, primarily it is a military metal and for the army money is no problem.
Visaton say on their discussion-forum that pure metal sounds awful.Thankyou for this info, it spare us time and money.
For sure - dipoles behave different in coupling/exciting the room modes as monopole speakers (boxed speakers) do - move them away from the back wall - this will increase LF output due to better exitation of the lower room modes.
I respectfully submit that bending wave transducers are not dipoles, they are bipoles.
The whole cancellation effect of dipole operation at lower frequencies is out the window, so to speak with dipoles. On the other hand with bending wave bipoles, Bending waves on the rear surface will be in phase with the front surface. It's just a matter of careful dampening at the the edges of the board to retard reflections back to the epicenter without impeding edge motion too much. The edge is where the most travel of board takes place, thus providing the highest amplitude of lower frequencies. Mounting a bending wave transducer can be a tricky situation. Thats why many of us have reported that lifting the board from the floor has a dramatic effect on bass. The "Q" can be very high and narrow, in some cases undetectable by a spectrum analyzer, but quite noticeable by ear.
Electrostatics are dipoles, very fast and accurate, but they need to be large to get bass. NXT type panals need to be large too, but mostly to move anough air.
[/b]Electrostatics are dipoles, very fast and accurate, but they need to be large to get bass. NXT type panels need to be large too, but mostly to move anough air.
Why are NXT type panels called distributed mode speakers? Because they are neither pure dipole neither pure bipole. They have opposite phases 'distributed' on every side of the panel. They don't pressurize a room like monopoles and bipoles would do at very low frequencies. But they don't have a clear dipole separation either. And their ability to produce bass is very well defined by their size in the first place. A small DMS will NOT produce bass, regardless how much air you are able to move with it.
It would seem that at some point this technique changes from true bending waves to something more along the lines of pistonic behavior. We may need to think about something Bob Carver did with his woofer system on the original Amazing Loudspeaker by having a high "Q" at low frequencies to make up for cancellation due to baffle width. It's hard to say at this point, we're not dealing with true bipole or dipole operation, but a chaotic transition.
It would seem that at some point this technique changes from true bending waves to something more along the lines of pistonic behavior. We may need to think about something Bob Carver did with his woofer system on the original Amazing Loudspeaker by having a high "Q" at low frequencies to make up for cancellation due to baffle width. It's hard to say at this point, we're not dealing with true bipole or dipole operation, but a chaotic transition.
They do sound omnidirectional, compared to Stig Carlsson's designs, familiar here in Sweden, I think that the panel's response are very much more omnidirectional than Stig Carlsson ever accuired with his dynamic speaker designs. But even those old designs did show remarkable 'no shows'. :)
I thought i read that these are just speakers with no cone? Why couldnt you take another driver and just cut the basket off and remove the cone then attach it the same way we do these?Maybe the suspension of a exciter is different than a cone driver, Iam not sure.
Depending on panel size, weight, stiffness and amounts of damping in the panel, my plywood panel seems to go from 20 k to 250 htz in pretty much nxt mode. Below this I am sure it is a piston. As a contrast I tried Foamcore again (as the sound was dull and boomy). [/b]
Oddly, I use 20"X30" black foam core to conduct tests, using just one exciter per channel. Near field pink noise is pretty flat from 30 to 16,000.
Placing the board on the floor causes an immediate drop in bass below 60 hz. The boards are not cut off at the corners, but bass was kind off buzzy and not clean. Mounting the boards along the long sides directly in line with the exciter produces clean and deep bass. I have four dozen exciters and plan to expand my prototypes to 24"X72" and run 8 exciters per board. They will be mounted on the long sides as in the small version. Before I do that, I'll sprinkle some salt on the front surface of the 20"X30" single exciter board and run a sine wave sweep for examination of the wave pattern. A bit "Caveman" perhaps, but I think there's something useful to be learned in doing so.
Far field pink noise tests are very interesting! It makes virtually no difference in spectrum analyzer readings where the microphone is placed. Chaos of the bending waves coming off the front and rear of the panels seems to even things out. This may account for the stereo image to remain intact throughout the listening area.
Most curious!!!!
This technique delves into areas that are not entirely charted (even by NXT).
I think if we persevere, we will find what works and what doesn't work. I know from experience that pure science does not always work as expected. I have considerable technical background, but a lot of Thomas Edison too!
Nobody likes to waste time and money only to have their efforts dashed to the ground in failure. We have a challenge here and in my opinion it's worth pursuing. We may not get the results we hope for right away, but half the fun is in the tweaking.
I for one, love a challenge!!!!
Depending on panel size, weight, stiffness and amounts of damping in the panel, my plywood panel seems to go from 20 k to 250 htz in pretty much nxt mode.
I made those for my son who wanted to replace some swan m200 speakers from his crowded desk. The Swan m200s were the unpowered slaves which I got from theaudioinsider. The M200s were hands down better. The small panels were more like cheap clock radio speakers. I think it is important to go big with these panels to get good sound.
captainjack115
I too have also noticed that pushing the side of the panel firmly against a wall does seam to improve the Lf.
One thing I failed to mention was that I mounted the panels on foam, they were not on a solid frame. (Controlled Flexing?) I just didn't want someone trying this without knowing they would need a soft mount on both sides of the panel. I stopped worrying about watts and monitor the exciters for heat with a hand held laser thermometer.
Jack
As a side job, I have engineered over 9 CD recordings for a local recording studio.
I have to remember not to refer to you as "Ziggy".
Anyway, Life is funny in that we run into people that share a common interest.
I built a recording studio for the radio station I engineered in the mid 60's.
The difference here being that I was cutting master discs on a lathe.
Where has the time gone?
Flow of consciousness is sidetracking my thoughts.
Despite using electronics to enjoy music, I prefer listening to live unplugged music whenever possible. Bass is tough in a listening room, my room has a lot of gain below 30 hertz. Jazz with acoustical bass sounds pretty good for the most part. Artificial bass is quite tactile and impresses the heck out of the average person.
I followed your posts for years on that "other" forum about your experiences with NXT technology. Your two ears, observations, and continuous reports have been invaluable to all that have read what you had to say.
It's possible that people may think you're trying to clone Podium's design, but you have actually expanded the principal and continued the progress towards a better sounding loudspeaker. The fact that you've been so willing to share your discoveries both positive and negative, has been most gracious.
I don't know about Australia, but here in the U.S. high end audio establishments are few and far between. Large cities are still carrying the good stuff, but where I live it's all mainstream garbage.
My point is that it sounds like you could find yourself in that high end speaker business, if you have the time for more R&D. Money??? Get your speakers to a
CES for auditioning, you'll find a backer!
Jack
ITs good to have a second pair of ears and hands to help sort things out.
If this is in fact a ''HOLE''.............it may be NXT's suggestion to TDK to squeeze some more high frequencies from the exciter's voice coil? :o :dance:
What about the panel thickenss? Does it have any change in bass or fullness?[/b]
I gave a couple to my friend but he didnt have any of the gator board, he used a section of 1-1/2" thick foam and he said it sounded good but i dont have any to try.
I want to build a panel the size of a bookshelf with about the same fullness but lower profile. For rear surrounds, or even a center. I built a center but its a tad to thin sounding for what i like.
I thought i had gator board but i guess its not, i guess i just have black foam core poster board. The black stuff i have is different then the white but its not near as rigid as what i read the gator board is.[/b]
I like the foamcore stuff it just needs to be bigger.
I thought i had gator board but i guess its not, i guess i just have black foam core poster board. The black stuff i have is different then the white but its not near as rigid as what i read the gator board is.[/b]
I like the foamcore stuff it just needs to be bigger.
I'm thinking of getting a 48X96 inch piece of foam core and having it cut in half lengthwise then cut to 72 inches for both pieces.
I'll put 8 exciters on each panel, but before any I make big panels I'm trying the aluminum on the front.
This will require that the hole for the exciter is slightly larger than the diameter of the exciter. The next problem is having the end of the exciter be exactly at the proper distance to touch the aluminum sheet.
The sheet of the aluminum would need to be just thick enough not to bend or sag, then well glued to the panel as to allow a low loss acoustical coupling.
Joining two different materials in this manner, may just give us us the best of both worlds. Decent bass and just a slight boost to the high end, would be a good step towards a panel with acceptable characteristics.
Jack
What do you think it would sound like if i cut out a section and suspend it with rubber bands?[/b]
I bought some of those 55 cent onkyo tweeters and they dont sound that bad.
(http://i5.photobucket.com/albums/y191/BowerR64/Hi-Fi/Panel.jpg)
Wich do you think would sound the best?
The number of exciters seems to make a difference in the HF response. With one exciter my 2'x4' gatorfoam panel goes up to 15Khz with 2 exciters the HF rolls off at 12Khz and with 3 or more it is lower still around 11 Khz. I presume the multiple exciters must be canceling out the high frequencies. I wonder what role spacing between exciters plays.
(I tried different spacing and it did not seem to make any difference)
After reading some of the earlier discussion about dipole vs. bipole, I thought I'd try something very different - exciters on both faces of the panel. Complete Fail! The sound was just awful. The exciters must be canceling out.
How are you running multiple exciters on one panel? series or paralell.[/b]
If you are running them in series i can see why its rolling off the high freq because your adding another coil. The coils act like a choke i think and the tend to block the HF the larger the coil is.
Im only running one exciter but im running 2 of the cheaper ones because they are 4ohms but i dont think they even sound as good as the dayton ones.
I must admit I have been following this thread with great interest for a while now. I got a chance to get a few exciters from a local dealer ...
The mystery of NXT is not in measurements..........it's in practice with actual REAL materials and experimentation............lots of it as most here already know.
[/b]
So, I suggest that the next time you play around with useless materials such as MDF and hold them with one hand while measuring their ''horrible'' frequency response curves, and posting them on this thread, keep in mind these variables(and there are probably even more that we are not aware of) and then try and convince us all that they are accurate and reveal a midrange only panel that ''lacks overtones or ''harmonics'' or '' sound acceptable only with a small number of instruments, if at all'
Bruno, here are the waterfalls (God forbid!), panels look bad, but they do sound better than dome tweeter...for whatever reason
Well said Jack! :thumb:[/b]
I'm glad you demonstrated the ''other side of measurement techniques'' :green:........just goes to show what we're dealing with here :scratch:
Rob.
It only took a matter of minutes if not seconds to realize that I had a poor man's Podium producing sound that I never thought was possible in a home environment.
I wonder!!!
Has anyone here had a look at Podiums' patent claims?
I for one, have not seen their patent, but there must be some mention of NXT technology.
I don't think they can lay claim to multiple exciters, only the type and the way they're mounted. This along with the type of panel material and they way in which it's mounted. I'm sure there are other claims as to their uniqueness as a loudspeaker system. I won't speculate beyond what I've just mentioned.
My point, (yes I have one) is that anyone of us may come up with a "similar" system that may indeed have qualities worthy of enterprising commerce.
Personally, I just love the idea of making something that contains a part of my own creativity. It's sort of cool to make something that works amazingly well and knowing that the guy down the street can't walk into a store and buy one just like it.
This is the sort of thing that sets the DIY'er and entrepreneurs apart from the rest of us, we are a unique breed !
Despite having a technical background, I'm a "hands on" kind of guy.
No one here would be shocked to know that scientists and engineers the world around have made their breakthrough discoveries by empirical means.
After their discoveries are made they create formulas to fit their technology.
Please don't flame me!
"Most" of the time, technologies are a germination of an idea in which known science is applied until the desired results are obtained.
"BUT"!!!! If we get into a situation where established science is not yielding expected results, we must question our testing methods and possibly find new testing procedures.
Quite often, well heeled speaker companies have there own anechoic chambers. Not too useful below 200 hertz, so they resort to quasi-anechoic methods to try and "gate out" lower frequencies. Many times they'll make a composite curve of anechoic and quasi-anechoic results. Still not a room friendly way to test a loudspeaker.
We're pretty lucky to have NXT technology to make our own loudspeakers.
They're fairly room friendly, so there's little need to go outdoors and make measurements.
I know, I'm beginning to sound like a cheerleader for NXT. I don't have the legs for it, believe me!
I've been designing and building ESL's for over 25 years, they're great sounding speakers. The downside is getting adequate sound level and acceptable bass.
Also, they're more trouble to build. Expensive step up transformers and bias supplies, high failure rate and many amplifiers balk at driving a capacitive load.
Oh, I forgot...............No magic!
Jack
It only took a matter of minutes if not seconds to realize that I had a poor man's Podium producing sound that I never thought was possible in a home environment.
Quite often, well heeled speaker companies have there own anechoic chambers. Not too useful below 200 hertz, so they resort to quasi-anechoic methods to try and "gate out" lower frequencies. Many times they'll make a composite curve of anechoic and quasi-anechoic results. Still not a room friendly way to test a loudspeaker.
Boy, pretty bad when I have to quote myself.
I meant to say that the "reflections" of the lower frequencies were gated out.
Jack
Zygadr and fivestring.
You know that panel material I have been testing ,the one that is very rigid ,the one that got very hot but only melted the foam inside .
You will never guess what it is made of . :oops: :roll: :duh: :lol:
I was hunting around many moons ago and found a supplier for 6mm single ply(which I think would be better?) but never got to buy or try it.
I'm not certain if it may or may not require stiffening at 6mm?.........double ply at 6mm definitely wont, but may not transfer the sound from front to back as well..............don't know unless we begin testing :scratch:
Here is another. http://www.tudelft.nl/live/ServeBinary?id=236fce6e-97a8-456e-9624-726037625b13&binary=/doc/Erwin%20Alles%20thesis%20MSc.pdf
Brian
I`ve just tested some Dibond panels that sound very promising, detailed and smooth at the same time, more so than any panel I`ve come across so far and also measures reasonably flat.
This product looks intersting.
It may improve things from the exciter side, but I'm not sure the foam in the middle will allow the aluminum on the front to make as much improvement.
Certainly deserves a better look.
Jack
captainjack115[/b]
He seems to be saying I measured these and they look bad but I think I could be doing it wrong? :duh:nuff said
In the mean time,running these panels with CLASS D amplification and BATTERY POWER leaves me speechless.
I played around with that little Dayton amplifer from Parts Express.
I have to admit, the highs were clean and crisp and not in any way too hot.
One day the little amp died, some day I'd like to try a more powerful unit.
Jack
I`ve just tested some Dibond panels that sound very promising, detailed and smooth at the same time, more so than any panel I`ve come across so far and also measures reasonably flat.I had a private conversation with a guy on the other forum and he prefers Dibond to Gatorfoam. I am a bit puzzled that it works so well, since it is quite heavy (2.9 kg/m^2). This makes me think about Lamera Hybrix, a stainless steel "microsandwich", which has 1.5 kg/m^2 in its lightest form. http://www.lamera.se Its middle layer consists of short stainless steel fibers that reach from one cover sheet to the other. I wonder whether this structure alone (with the absence of any damping polymer) provides enough damping.
Gentlemen, I think I have it!!!!!!!!!!!!! :o :o :o
As we have struggled to better the Gatorfoam, I had an idea which goes way back to the roots of this NXT panel saga.[/b]
We're champing at the bit!!!!!
Jack
el'OL..................................... ...correct!
The piezo, as I have found, matches the output of the panel's sensitivity perfectly and blends in better than I could have dreamed for
I was expecting to have to use resistors, capacitors and or step up transformers, but by sheer luck NONE of this is required.
Having designed ESL's for many years, I have some reservations about the capacitive load of a piezo element. It's a high impedance device and as such acts as it's own crossover. By this I mean that it's a better impedance match at high frequencies than lower frequencies. The driving amplifier is going to "see" more capacity at higher frequencies and be more reactive. Some amplifiers can be unstable and oscillate under capacitive reactance.
In real world applications ESL's can be 4 or 5 mfd, If possible, measure the piezo load just to see what you have. It's probably nothing to cause concern, just something to keep in mind.
Otherwise, congratulations!!!
Jack
Measured the piezo : 0.025uf.[/b]
Don't think that this should be a problem?
j gale..............that is the million dollar question! :scratch:
I feel that I may have fallen in to the brighter is better (as opposed to accurate) trap?
One thing that concerns me.
If a one wishes to look at this project from a "purist" standpoint, there would be a problem of aesthetics.
I know for a fact that the magneto dynamic exciters are capable of upper end frequencies beyond 20,000 hertz. The problem, (as it has been all along) is one of coupling the exciter to the outside world, so to speak. Like it or not, "Nomex" has been the material of choice thus far. It's very low mass and quite rigid. If one looks at the construction of this product, it's elegantly simple but not easily copied by the average person. I must admit, I've laid in bed at night thinking of a way to make my own version of Nomex
Shelley Katz still had to do a bit of a balancing act with the Podium 1, by adding an hp capacitor in one or two exciters despite the Nomex. All in all, I think Shelley has been very good about revealing as much as he has. The Podium point 5 uses no other passive components to my knowledge, if so I stand corrected.
Hey, I have a piezo horn laying around here someplace. I still may give it a shot anyway. As a horn tweeter, it totally sucks. One other thing, it may be rated for no more than 20 watts, I can't remember.
Jack
However, this time the cone will be taped to the back of the panel, more towards the edge, rather than the middle with the rest of the exciters.
I know that over the ''other forum'' they were promoting the rounding of corners.
Are you aware of improved results with this technique?
I say this beacause those guys over there have ''lost the plot''...........big time.
I haven't been checking the "other" forum with any regularity, my thoughts are that they're stuck in a rut.
I can't say with any real evidence that rounding the corners will improve performance without actually trying it. From a physics standpoint I believe rounding the corners may have audible benefits.
The epicenter of the bending waves emanating from the exciter are concentric until they hit the edge of the board. The waves grow in amplitude as they travel away from the epicenter. (Bigger board, more bass).
Here's what I think may be happening. The waves hit the edge of the board and have nowhere else to go but bounce back in the opposite direction.
Thus a need for dampening. I don't think it's such a big deal on long edges, but when the waves hit a corner there must be a great deal of turbulent reflections running into each other at 90 degree angles. After all, the board is getting smaller as the waves get closer to the corner.
Have you noticed the increase of vibrations at the corners? These may not necessarily be "good vibrations". (Apologies to The Beach Boys).
It stands to reason that the concentric waves will behave in a more predictable manner when running into a curved edge. A gentler cross wave reflection should result. Some might be thinking of using a round board instead of rectangular, but I don't think it's an efficient idea.
The reason being that we are using in line multiple exciters and it would just take up too much real estate on the board. No sense in wasting radiation area and losing out on bass. No need to go elliptical either for the same reason.
I'm going to do a caveman test on a board, by sprinkling salt on a horizontal board with one exciter. I'll then sweep an audio signal generator and note results. Then repeat the test with a rounded corner board.
BTW.... You could be right about the tape. It could come in handy to be able to walk into a store and buy a roll.
Jack
I find it frustrating yet humorous that the people who have disregarded, slagged and brushed off this DIY success story without even giving it a decent go or try and have relied on measurements and the negative attitudes of others and other forums to convince themselves that this is just a load of B.S.!!
We are all big boys. No one has suffered from Ziggy's enthusiasm. It has been a pleasurable adventure and continues to be so.
I agree!!!
I'm reminded of something a man said to me quite a few years ago.
The man was dead set against buying a color television, his reason was that he was waiting for it to be perfected.
Well, that was years ago and now we have high def TV. It's still not "perfected", but all the time the man was waiting for TV to be perfected the rest of us were enjoying our programs in color.
The sound of a loudspeaker system has and always will be subjective.
We're having fun and learning as we go along.
Jack
This looks a bit like the chicken and the egg story to me ,if you read you post first the quote seems to be answering your post [spooky].
DanTheMan, I know what sedge meant in his first line and.......... no.............I'm not going to explain it to you.........heaven forbid!...........I might be accused of leading you in to the dark lands without evidence.
We all know what Sedge meant!!!
"Most" of the guys on here are quite intelligent. I will "not" waste my time nor the time of my fellow readers by engaging in a P*****g contest.
Anyone who feels contrary to my opinion on this attack on Zygadr will be ignored by me. Don't even try!!!!
Zygadr is an intelligent, creative and savvy guy that deserves better. Whether he's still on this thread or not, he deserves an apology, big time!
I've said my piece, let's get back to the subject at hand.
I have some ideas that may extend high frequency response, if anyone cares to hear them.
Jack
I have the white GF not the black so I a cannot compare. But it seems my white panels are not producing as much HF as zygadr's black panels are. My panels are a little smaller and I am using the cheaper PE exciters so that might be the issue as well.Well, I have one (or possibly two) of the original Sonic Impact sound pads (that I'm guessing Zygdar used) so if you want to experiment , compare and report back, I'll mail it to you (assuming you're in the US)
Dan,
Most of us are aware of some of the shortcomings of the design. But it has been a fun project at not much cost. In the frequency range that the panels produce, that sound is wonderful so we keep trying to improve. Ziggy's enthusiasm is infectious and that keeps the experiments going.
So don't mind the circling of the wagons...happens in all small groups.
Captainjack115[/b]
Yes lets get back to the subject at hand, always glad to hear any ideas that could further the development of our panel speakers
sedge
But in the end I wouldn't be surprised if we end up with Gatorfoam. Then to me it is mainly a task to see how bass could be improved by subs or perhaps OB-bass.
For the high treble I would easily suggest some omnidirectional super tweeter solution. And that certainly will exsist.
I was very pleased to know that someone on this forum actually heard Ziggy's speakers. "That's evidence"!
I can't stress enough that's it's very important to round the corners of these panels. Additionally, the mounting of the panels has a big impact on bass response. The panels must "not" sit on the floor, doing so will upset the balance of resonance distribution. The panels must sit in a spring-like suspension. I'm getting bass well into the low 30 hertz range.
Jack [/size]
I have heard Ziggy's Black Monsters not for a very long time but long enough to say that his Gatorfoam finds are great. He may very well sit on one of the best high bass, midrange, low/mid treble speakers there is. And that's no small business.
That's interesting Captainjack, Bob's panels just rested on the floor and no corners were specially rounded. But how should we get them into the air ?[/b]
/Erling
Hello,
i'm new and i'm really interested in the project.
I've a question, why don't use a honey-comb core Nomex panel as the original Podium Sound model 1?
There is something wrong with that kind of material?
Hello and welcome!
There's nothing much wrong with Nomex, in fact most people on this forum would love to use it. Nomex is not inexpensive and carving it up for DIY experiments can be costly.
I'm working on an idea that may negate the use of Nomex, if it works I'll let everyone know what I did. There's no sense in several contributors of this forum duplicating my futility.
Jack
This is not an easy decision for me to make after the events of the last few days.
Due to so many kind and supporting personal emails received, from considerate and thoughtful people, pleading with me to return (some from people that I have not heard of or known about, some from all parts of the world and even phone calls from within West Australia and the Eastern States of Australia!),I will come back if you still wish me to do so on this forum , as it now seems very obvious that the NXT panel project has such great significance apparently..........to more people than I could have ever imagined.
Welcome BAck!!!!!
Jack
Firstly, I am not an unkind or malicious person despite my last outburst, which I sincerely apologize for............that was just plain stupid and I reacted impulsively.......again! :roll:
It seems very clear to me now that we need to accept measurement techniques, whether they are 100% effective or not. We need to be decisive and analytical of panel materials, mounting methods and ALL aspects of this project.
It seems to be a proprietary skript (by NXT) for AkAbak speaker simulation software.
Akabak is free for private users.
http://www.randteam.de/_Software/AkAbak/Download-AkAbak.html
To get access to the DML skript you will need a NXT licence.
-m
1. Panel suspension needs to be stabilized so that there is no further stretching downwards due to the effects of gravity.
Consider using a low mass compliant brace, with just enough lift to neutralize gravity. Something that would loop around and under the magnet and fasten to the panel just an inch or two above each exciter. I'm not trying to be humorous, but it would act something like a bra. Yes I know, I'm thinking about a rubber band, but we need something that won't lose elasticity over time.
It would be simple and we wouldn't look like we were trying to copy the Podium's to the last detail. Using a spine also means connecting it the frame and suspension system.
Just a little something to think about.
Jack
Whyis it that so many conversations in audio these days are gravitating towards Bras and Pantyhose?
To get access to the DML skript you will need a NXT licence.
jeffac
just thought, this is a piezo oops , won't work probably :duh:
very high resistance at low fr.bigger battery ? :scratch:
There is Something I have been meaning to ask for some time now ,has anyone noticed that If you toe the panels inward ,sometimes quite heavily,[even tried facing the panels at each other] you seem to get an almost 3D effect .
I am not sure If this is because of my long thin room or if it has the same effect in larger rooms ?
It makes you feel like you can walk through the image, as if there is more depth.
With the panels facing strait forwards they still sound good but it is more like a wall of sound [I think this is partly what I was hearing when I heard the podiums] which can sound a bit odd.
I did not try this With the small panels, say down to A4 size ,as the panels seem to give good ambience already.
This is also quite good for me as it makes the panels narrower and deeper ,so that I can have a bigger panel.
On normal speakers toeing in seems to [IMO]give a more central image .
If anyone can at sometime let me know if they can hear the same [or not ] It could be helpful , thanks.
I could just be going mad [who said that]?
Can anyone comment on the sound of (say) two 2 x 3 panels vs one 2 x 6 panels on a single channel. I ask because it's going to be hard for me to acquire large pieces of gatorfoam. At least the smaller pieces can be shipped with no difficulty.
Can anyone comment on the sound of (say) two 2 x 3 panels vs one 2 x 6 panels on a single channel. I ask because it's going to be hard for me to acquire large pieces of gatorfoam. At least the smaller pieces can be shipped with no difficulty.[/b]
Can anyone comment on the sound of (say) two 2 x 3 panels vs one 2 x 6 panels on a single channel. I ask because it's going to be hard for me to acquire large pieces of gatorfoam. At least the smaller pieces can be shipped with no difficulty.[/b]
My feeling is they would have to be seamed together in a way that would allow them to work as one large 2X6 panel. (Tricky)
The bending waves need to expand across one large panel to radiate lower frequencies.
Jack
If you can't get Gatorfoam, use corrugated cardboard.......it's better than nothing, or, trying to piece together smaller panels.
What If you cut a hole in the panel so that the lip of the back of the peizo can be glued to the front of the panel so that it is forward facing, this would make the peizo part of the front surface[nxt], radiating frequencies cleanly across the surface [no trying to penetrate through two surfaces and foam core ] ,hopefully this would sound cleaner from the front and louder .
aa...........O.K..............HERE WE GO...................the Re-board rep will visit me at work on a business and private
What's Re-Board?
I couldn't Google it. Can I get it in the U.S.?
Still using 20 X 30 inch foamboard, the highs are great and the lows into lower 30's.
I have two prototypes, one set has one exciter with square corners. The second set has two exciters and rounded corners. The seconded set sounds much better, a fuller sound with lots of volume.
Whether one exciter or two, the panels have a native resonance around 30 Hertz.
I would think that a larger panel would lower resonance, adding more exciter will change things. With conventional dynamic drivers, the Fs can be lowered by adding weight to the cone.
I have lots of exciters. Imagine having 16 or 32 exciters per panel? I don't know if it will play good, but it will play louder than I'll ever be able to stand.
Jack
Gatorfoam is most likely better suited to much smaller panels only? :scratch:
Let's face it........Gatorfoam sounds great, but picking up a sheet that's 78inches by 28 inches by one end and levering it in to an upright position, watching it bend like a banana in the middle is asking for trouble........I should have known better :duh:............it's just not rigid enough at that size.
Maybe 10mm would have been better..........but I doubt it :scratch:
Hello,
I'm going to copy the podium system.
So i need some information about the materials used in that setup.
I know there is a honeycomb panel made of Nomex but i'm wondering about the thickness...
then there is a mylar sandwich protecting the nomex honeycomb right?
even here i wish to know the thickness of the mylar.
I do not want to seem arrogant cause of this :oops: you guys are fantastic and you are working well, very well.
I'm learning a lot from your mistakes and your successes, but I would overcome this stage and use the finest materials to get as close as possible to a hi-end results.
many thanks to all :)
p.s.
clearly once assembled the panel, will explore the position of the exciters!
UPDATE :[/b]
The Re-board rep. will be seeing me tomorrow, 9.15 am Perth time here at my office.
As soon as the meeting, examination of the samples are over, I will report to this forum immediately on my findings and observations.
Who's going to be the first to try and generate Chladni patterns on an NXT panel at various frequencies?
http://www.youtube.com/watch?v=GtiSCBXbHAg&NR=1
Finally available:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-377
:rock:-m
Conventional cyanacrylate super glue is not vibration resistent. Moray James who has developed a commercial bending wave transducer recommends Black Max, a cyanacylate glue with rubber as filler in the other forum. I believe (seen in an Araldite ad) that the speaker industry usually uses methacrylate glue. Epoxy is probably not used because of long hardening times. I used Pattex Repair Extreme,because I didn't find thin double sided tape in the local stores, advantage is that you get the RE in in very small quantities in construction stores (at least in Germany). The manyfacturer claims it is vibration resistent. It was quite hard to get the exciter off the panel (of course it was destroyed by doing this.[/b]
Speaking of Moray James, has anyone heard from him? We chatted on the phone quite often and about a year ago he said his phone would be off for an extended period of time. His email is not working either, unless he has a cable modem. In most cases: No phone, no internet, no brainer!His latest post on diyaudio is from today. Try to contact him there.
Can these panels rock?[/b]
Can they translate the musical energy and the impact of a rock concert well? I mean macro-dynamics, the mojo... How do they compare to a OB with classic dynamic drivers?
[/b]
where did you find this tacky tape locally. I finally found the time to go buy a sheet of black gator foam yesterday.
Does the tacky tape mentioned inthis thread cure rigid or is it permanently supple. I'd think the ideal adhesive should tend towards rigid ( not completely though) in order to facilitate efficient energy transfer to the panel
The Tacky Tape remains sticky to the touch after it's been exposed to the air. Instructions urge using it right away after peeling protective coating to start the curing process. So, I guess it never gets rigid, but holds on for dear life after curing.
I've also used Super Glue gel which does get rigid. I hear nor measure any difference from the tape and glue. I cannot say that the Tacky Tape is comparable in quality to the 3M tape Ziggy uses. It may be something else entirely, or in fact the same 3M tape under license. I can only speak from personal experience, it holds very well and for some people, easy to purchase.
Jack
Thanks, I bought some of the tacky tape this morning and am going to stick 8 buyout 4 ohm exciters per 2 x 6 panel ( wired for 8 ohm to ease the load on the amp and also hopefully increase the effective damping factor)[/b]
Sure would appreciate a report on the results.
My panel has 8 exciters at 8 ohms, but it's only 20 X 30 inches. Sensitivity is excellent and volume peaks were over 106 db at 16 feet away. Loud, very loud!!!!!
Jack
And has anybody tried a more permanent solution, like superglue for instance?
The results of another test may explain why some of you have no highs in your experiments. Using generic double sided FOAM tape killed high frequency reproduction. I mean, cymbals were totally MIA. OTOH, using the tacky tape (or possibly any other THIN / non foam based double sided tape) brought the treble back.
Another thought on the complaint about a lack of highs. I'm beginning to wonder if some are looking for the tizzy unnatural stuff that some speakers put out. My panels do very well with cymbals, triangles etc. clear, no hiss or tizz just sounds real.+1
...........The panels have, over the last week, despite numerous checks, LOST SENSITIVITY :evil:!!!!!!!!!!!!!
....I have inverted my panels a few times and heard the distortion dissapear, but the recent development in output loss can not be rectified as easily.
Where to go from here?...........don't know :?
Dan, Pretty much the same as the podium1 pictures. Same kind of spine and for his so called sound bridges I used the styrofoam backer rod. Helps take the weight of the panel off of the exciters and keeps the panel from pivoting as if the narrow line of exciters was a knife edge. So spiders are not stressed too much. My 1st panels have nothing holding the edges since there is no spine. My experience tells me that there is no penalty for restricting movement somewhat at the edges. Bass has not suffered.
I've had at least 3 instances of the tacky tape coming unglued from black gatorfoam over the past couple of days. I will monitor to see if there is a pattern, at which point I'll spring for the real 3M stuff
I'm sorry you've had a bad experience with the Tacky Tape. Maybe the surface on the Gatorfoam just won't take to it like the paper surface of foam core.
It was certainly not my intension to mislead anyone by my experience with Tacky Tape.
Jack
It seems to me that the exciters should be placed in a straight line and as close together as possible for maximum treble response and deepest bass. Spacing the exciters out would seem to cause issues in both domains. Anyone tried this?[/b]
Dan
Nice work doug s !!!!!!! :thumb:..........we have a true ''Podium clone'' :Dhey, don't praise me for anything more than showing j gale how to post pics of his panels to the forum. :lol:
Zobsky, I have had no problem with the 3M stuff letting go. I cleaned the plastic footers on the exciters and the areas of the panel that the tape contacts with 99% isopropanol alcohol 1st. I think that this is a necessary step. I guess that a glass cleaner would be OK too.WIll try this (if/when) they come loose again ( prior to mounting I cleaned the exciter with alcohol, but not the panel)
I've had at least 3 instances of the tacky tape coming unglued from black gatorfoam over the past couple of days. I will monitor to see if there is a pattern, at which point I'll spring for the real 3M stuff
I'm sorry you've had a bad experience with the Tacky Tape. Maybe the surface on the Gatorfoam just won't take to it like the paper surface of foam core.
It was certainly not my intension to mislead anyone by my experience with Tacky Tape.
Jack
No problem
I have made some very positive discoveries towards advancing on the sound produced by this technology and can assure you that a STORM IS BREWING!Bring it on! Don't just say it, spray it! aa
One reason is better sound. Not just better---MUCH BETTER.Oh? How so?
Come to think of it, you shouldn't get 6 dbs each time you double b/c you won't get twice the surface area. Man do I wish someone could take measurements. After I get a few projects done I'll make and take my own but perhaps this thread will be dead by then. :scratch: Seems like the pace is slowing--which totally sucks b/c I think Patricks panels are very inspirational.even disregarding surface area, doubling the amount of (any) drivers will give you a 3db increase, not 6db. i.e.:
Dan
Doug, that works if you don't account for impedance, but halving the impedance will also give 3dB thus 3+3=6 if you run parallel connections. Running each off it's own amp should work how you describe. Of course you can't do parallel infinitely or you'll fry your amp. Eventually you have to start adding some series connections depending on what your amp can do.uh no dan, i think you are mistaken. while it's true that some amps can double their output when its impedance is halved, (tho many cannot, especially tube amps), all this means is you may not have to turn up the wolume on your preamp as much to get 1w to your drivers when run in parallel, and you may have to turn it a bit higher to get 1w when run in series, due to the differing load the amp may see. but 1w is 1w; when a speaker is fed 1w, the increase in spl for adding speakers is as i described above. if you have one driver capable of 90db/1w, running two in series or in parallel will still theoretically give you 93db/1w.
Theoretically,
1 driver=90
2 drivers in parallel=96
2 drivers in series=90
and there are a numbers of ways this can all add up when you get to multiple drivers. That's why I was wondering what others have measured so we can know what we're going to get when we add more drivers. I think that the addition of regular drivers is well understood by most people who are into DIY audio, but this stuff is different. I don't know how the rules apply here. I know Ziggy says he's getting more efficiency by going with more exciters, but how much and at how many I don't know. It gets hard to make an informed decision and so far it looks like we're not far from square one with exciter understanding.
Dan
uh no dan, i think you are mistaken. while it's true that some amps can double their output when its impedance is halved, (tho many cannot, especially tube amps), all this means is you may not have to turn up the wolume on your preamp as much to get 1w to your drivers when run in parallel, and you may have to turn it a bit higher to get 1w when run in series, due to the differing load the amp may see. but 1w is 1w; when a speaker is fed 1w, the increase in spl for adding speakers is as i described above. if you have one driver capable of 90db/1w, running two in series or in parallel will still theoretically give you 93db/1w.
doug s.
I so agree that NXT speakers have a mind of their own....ie no amount of actual planning will result in a perfect product...being an engineer i made that mistake .
Seems you broke many of the guidelines discussed in this thread in developing your panels. Care to share from all your work? What did you try and find? Both will be useful to the community as a whole. Maybe this can lead the rest of us to higher quality designs.
I once spoke to a sound engineer while in my teens and we discussed speaker cones.
I still remember his stern comment on the new wave of cone materials starting to surface at the time and his insistance that I will find out one way or the other that paper sounds best...........no contest.
I thought he was just an old fashioned fool.
Just a passing thought here, but has anybody tried these exciters as the motors in a linaeum-style driver?http://www.zilionis.com/forum/viewtopic.php?t=289
Amazing old radio, but the language loses me. Is that a linaeum-type driver?The diaphragm is kind of a half linaeum. The drive unit is an electromagnetic one, with a vibrating core and a fixed coil.
Have a look at the above exciter..............it has much more power handling, a 2 inch ferrofluid voice coil, can be FREE MOUNTED.............WOOHOO!!!! and nearly 3 times the BL force factor of the Podium 1's best and NXT's best exciter!!!!Re also contributes to the electrical damping, so as it is a 4 Ohm driver you can more or less multiply the value with sqrt(2) compared to an 8 Ohm driver. I wonder how such an insanely strong motor shall produce any bass.
Does anyone know if its a fuse or a cap? also if its a cap what is the value of it?
The one on the second transducer says 80uf, i went back threw about 20 some pages but i cant find any info on the other cap value.
If its a resetable fuse maybe i should keep it hooked up?
The two passive components are soldered on the transducers to provide a high pass filter. So the large one is the capacitor and the small one you are questioning is a PTC resistor. If you are trying to use the transducers as full range speakers then you should remove both....
jeffac,.....If you're still watching this thread, I have come accross some TUNG OIL in our large local Hardware store. There are a few varieties.......water and oil based. I presume you used the oil based one?
Is this worth a try with a large sheet?......if so, which TUNG OIL type exactly do I need?
:eyebrows:.....................is there anyone out there???? :violin:
jeffac...............has that bloody stuff dried yet or not?
.....................is there anyone out there????
vaugi, foamboard is fine and many have used it. I would suggest that corrugated cardboard be used as your first attempt........about 3-6mm in thickness and as large a sheet as you can find(within reason).
Forget the exciters from that ebay product............they are very low powered, compact/slim versions and I would not recommend you wasting your money on them.
Go through Parts Express and get the proper ones even though the freight hurts.
Hi all I have been reading this thread with much interest. I have not decided whether to go with a single driver; the 15 wat 8 ohm, or two of the smaller 10 watt 4 ohm exciters. i wish that there was a better data sheet including the sensitivity ratings.an amp w/a stiff power supply can handle 2 ohm speakers...
a good source for the double walled cardboard is your local piano store. I checked out their recycle bin and scored a nice 2x5 piece. they have alot of board there but the rest was triple walled which i thought would be too heavy
A quick question is there a sonic dissadvantage of wiring in series over against parralel? If we are using the smaller exciters at 4 ohms and just two of them, series is the only option
A quick question is there a sonic dissadvantage of wiring in series over against parralel? If we are using the smaller exciters at 4 ohms and just two of them, series is the only option
jeffac...........so, .............it finally dried.............thank heaven's for that :green:
In West Australia, ''PACK AND SEND'' is a company that has many branches all over Australia:
http://www.packsend.com.au
Getting a couple of 8 X 4 sheets is no problem as they have many smaller retail outlets everywhere.
Two of the above sheets in 6mm double ply is $36.00 (AUS).
Hey jeffac................can you describe ''twin cushion''?..............
Mightym go with the double layer. It's still only 1/4" or 6mm thick, much more rigid and one layer has the flutes much closer together. I tried the golden ratio as well (pretty close to jeffac's size) I couldn't hear any advantage over my 2'x6' and so went with that because 30" plus width is just too big for my room. The 2 for $5 are the deal of the century. Their low price has nothing to do with quality or performance. I believe that they are probably the best of the lot. I rounded the corners of mine as well and although not a huge difference I believe an improvement. Cat 5 works well but will make noise if not secured. I really believe that cardboard (DOUBLE) is the answer. Natural tone and as Jeffac said decay. Big step up from Gator. Can it be enhanced by treatment? It will be fun to find out. PS I think 4 exciters on a 6' panel is better than 8.
Guys,
I had a more relaxed listen to the big panel last night, couple of play throughs of Jack Johnson - On and On - with low bass to loosen up the exciter suspensions, and then on to Harry Manx - Wise and Otherwise followed by Alison Krauss - Lonley Runs Both Ways. Impressions....... the "Mothers of Tone" have landed. :eyebrows: :eyebrows:
Bass is there a plenty, mids clear, HF there .... all with great dynamics. Instruments like fiddles and banjos really have natural tones, as with bongos etc, indeed all instrument textures are fantastic and vocals just beautiful. :thumb: What is really amazing is the natural long decay of sounds, which irrespective of whatever else is being played, just fade naturally into oblivion. :eyebrows: And this was still with only one large panel combined with my small single exciter panel and piezo cone panel. jgale ... you must be one happy camper. :D
And speaking of piezo tweeter cones, as the corrugations of the cardboard fit a kebab skewer perfectly, these provide a neat and easy way of linking panels together. So I've just placed a piezo tweeter cone panel on top of the large panel. :green: Unfortunately everyone is still asleep here and the minute, but I can't wait to get a chance for a listen. I think that by the addition of extreme HF is going to be the icing on the cake. :eyebrows: Obviously the added piezo tweeter cone panel is just what I was using before and for testing and I'd trim it down to something smaller, neater and maybe curved and glue the kebab skewers in.
main Floorguard-treated cardboard panel with piezo tweeter cone panel attached
(http://i337.photobucket.com/albums/n390/jeffc_pics/P1231004-1.jpg)
piezo tweeter cone panel lifted to show the kebab skewer attachment method
(http://i337.photobucket.com/albums/n390/jeffc_pics/P1231005.jpg)
Unfortunately I'm off camping for the next couple of days so that second panel build to assess them in stereo will have to wait... more excuses :green:
cheers.. jeffac
PS
Double Wall Corrugated Cardboard Sheet. (also known as Twin Cushion) ...
Mightym We have all stayed away from having an exciter at the panel centre based on what we can gather from NXT.
I just arbitrarily used a QT or litre paint can as a pattern to run my Knife around. The result looks good.
Good stuff jeffac,
only one question regarding the double corrugated, I was inder the possibly mistaken impression that the corrugations were perpendicular to each other, providing panel stiffening.
Did I just totally miss something in my reading here? :oops:
Could we possibly see the backside of your panels too?
John
I think the idea of placing the panels between two sheets of plywood or mdf is a good one, but wax paper or something will need to be used to prevent adhesion to the mdf/ply, and the wax or waxpaper will have to be cleaned off the panels afterwards.
Polyethylene should work well. I don't know if many have access to large enough sheets.
only one question regarding the double corrugated, I was under the possibly mistaken impression that the corrugations were perpendicular to each other, providing panel stiffening.mightym, all the double-layer cardboard I've seen so far has been made like this... and as jgale has described for the cardboard used for his latest and greatest panels. Envious mate :drool: In fact I like the differing thickness laminates (2 mm and 4 mm) with corrugations offset for both rigidity and spreading any resonant frequencies that could establish due to uniformity... and this is the non-conformists OB thread.... :green:
o.k : :roll:...............I give in..............gonna go to Pack and Send and get me some corrugated cardboard sheetStay calm Clint and keep that 45 in its holster :green: Fantastic quality cardboard and if anything like the sample I picked up... my guess is it will be absolutely amazing panel material even naked... perfect for the job…. I can't wait to get a sheet of the stuff home, just need to find a way of getting it there in pristine condition.
A question however, ..............how do you know if it's of superior quality?........is there an easy visual/mechanical way to check, or is it graded?
Why do we need two pannels to get stereo? It is just a bad habit, NOW we can built a coherent stereo dipole
with all drivers on a same row, for example a 1.40m x 1m vertical pannel can give very good stereo effect up to 5 or 6 meters.
POL
Glue? do you guys have the same units i have? :|Scream bad? or scream good?
Maybe this is why mine scream :duh:
(http://www.audiocircle.com/image.php?id=26239)
Dan, as I saw my doctor yesterday, I asked for two of his largest syringes that he had (I reminded him that I was not in to Narcotics :green:) and he supplied me with two that will do the job nicely. They only hold 15ml, but that's safe to squirt the Shellac down each flute to judge penetration and effect.
"I leave this with you for comment if you like. I've been factual and honest with all here.
I believe that we have come as far as we can go within the limits of a diy panel.
To me it's a speaker that can be used for some music, but fails on a good chunk of others and is dependent on transient severity and power input to survive."
I agree!
I haven't posted for a while because I had nothing to contribute. In my opinion, one exciter per channel and some cardboard works very nicely for an up grade in sound for a computer.
I been playing with line sources with amazing results. Full range with bass to 20 Hertz, no crossovers.
Hi Mikadosan,
I´m using two different kind of exciters on my prototypes. The other pair is using the 32mm balanced exciters (4 exciters per panel) and the other protos are using the new 25mm SFH exciters (quite strong ones!!). Balanced exciters seems to be able to offer a very neutral and natural sound with this panel type. SFH exciters are almost as good as well but will offer a little bit more sensitivity and bass extension.
-Mikadosan
Wow, thanks for all the info Sedge and Mikadosan.
SFX are about 2 miles from me!!!!!
I'm really keen to try a pair of their units but I think I'll try some cheapo's first if I get enough interest to get a group buy together, how many would you be looking for jonners?.
$100 will get us 20 exciters(thats the minimum order).
At current exchange rates that's about £64, if we split them 2 ways that's affordable for me.
Would you be willing to buy 10 off me (around £32 plus p+p from me to you) if I order 20 for us?
If 10 is too many for you maybe we can find someone else who's interested?
£3.20 per exciter is pretty cheap, anyone else in the UK interested?.
I have tried the following exciters already:I'm a little confused, do you mean these?:
- Dayton 32mm balanced exciter
- Dayton 25mm SFX exciters
And I can tell you that none has been as good as the Dayton (NXT) 32mm balanced exciters and 25mm SFX exciters.
Let's stop going around in circles which I believe is starting to happen............I'm not blaming anyone in particular, just keep it real guys.
tinnitusThanks sedge that's good to know, I'm definitely going to try them in that case.
the exciters from parts express might be cheep ,but they are not crappy infact they are very good.
WTF? We can't all afford to 'keep it real' at 500 bucks a pair.
Good luck to those who can, I'll be fascinated to learn mikadosan's conclusions should he choose to post them.
Does anyone else have any direct experience of the SFX units?
I'd like to ask again if anyone has tried putting two exciters facing each other on either face of a panel, with one unit wired to 'pull' while the other 'pushes'?
This might be the same as just mounting two units in separate locations but I suspect that there might be less chaotic interference if they were in synchrony.
Of course maybe DML thrives on interference.
I think my first experiment will be stretched silk (tight!) with exciters sewn on, and maybe some sort of resin or hardener brushed on to the silk (after stretching) to stiffen it.
I tried putting the cheap $5 exciters one on either side (both in and out of phase) on a cardboard panel and in both cases the results were terrible. It seems there is a lot of cancellation when one does that.Damn, that's a shame, thanks for letting me know, I doubt that results with stretched fabric would be any better in that case.
Your offer of possible help is very generous John, thank you.
I wonder of these exciters could be shipped in a padded envelope, as a personal letter, and whether it would speed the transit? I might be willing to assist, contact me with a PM
Have anybody tried some expensive but powerful exciters from Dayton like say the 427 ?Yes there definately is, see the last few pages of this thread.
I mean instead of installing several little exciters everywhere the panels, is there any interest in using only one, but powerful unit instead ? :scratch:
Success???...................this is totally insane...........on a small scale it can be done............large scale..............forget it!!........the CC wants to bloat, bend and warp............you can't fight this fact.
For those that have nerves of steel and endless patience.............use something else or use nothing and save yourself a lot of frustrating effort.
I got two matching CC panels up and running on my main system last night(untreated.......of course).
Played what is probablY the greatest percussion CD on this planet(I can post details is you like)...........weird label, one off find.
Results?, ...............after 5 minutes the backs of the exciter casings were uncomfortably warm to hot. After 20 minutes..............I was concerned that they would start to glow RED.
On top of this, the adhesive exciter mounting rings (the proper ones supplied by NXT) were softened by the heat and looked like they were beginning to release their adhesion.
Further to that, with two identical panel materials playing, I noticed that they have a sonic signature.............cardboard........ ....what else?
You can now openly accuse me of constantly changing my opinion on this technology, breaking out in over excited, premature enthusiasm(and you would be 100% correct!), but it is a known fact that the choice of panel material will greatly influence the final tonal output........and this is the most deceptive and annoying part of all!! :duh:
At first impression, CC sounded much better than all other materials tried so far, and it does...............but, they have a sound that reflects what they're made of.............as does everything else.This is without doubt the most unpredictable, fussy, temperamental speaker technology I have ever encountered...........and I'm fed up with it.
''Mother of tone''?.........yes it's there, it's more real than foam boards but it's not the ultimate..............I don't know what is.
Frustrated, I connected up the Gatorfoam panels that had 6 exciters and repeated the tracks at the same volume setting, noting the temperature...........same thing..........2 extra exciters won't provide the necessary power handling for any music with severe transients.On top of that, the Gator has it's own sound............muffled and weird tonality..........go figure.
I can conclude that if you listen to ''tame'' music at soft to medium levels with a ''medium'' powered amp, you can live with these speakers and enjoy them for what they are. Use CC as it's the best sounding.
Beware though, that these cheap(and even the expensive more powerful ones - 15watt ....?? :lol:............yeah..........impressive!) exciters have VERY LOW power handling capability and are inefficient..........VERY.
Now,............here comes the dilemna..........you add more exciters to increase power handling...............which it does, to a point.............with NORMAL levels/music.........BUT!............as we have found, more exciters is not allways good and in most cases leads to a detrimental effect on vibrational modes.In other words, it kills and confuses them.
So, .............we reduce the number of exciters...............REVELATION...... ............NOT! (power handling goes to shit!)
Some may say that this is a balancing act.................yes it is.
In my case and I know there are others out there who will agree, there comes a time when you wan't to hear a full symphony orchestra at live levels for an extended period of time (I mean ''LIVE'' not just loud.....however you gauge that) or a closely miked percussion one or something similar because you wan't to blast yourself to the back wall..........just for fun and the adrenalin rush!.............without having to worry that your exciters are going to melt or get damaged due to over excursion and going ''pistonic''..........which they WILL!! :o
It's o.k for the reviewers at 6 moons to say that the Podiums can reach ear damaging levels. Maybe they can............but for how long?..........and............ they have the luxury of using a panel material that is half the weight of our lightest diy offerings and consequently, they will sound at least twice as loud..........NXT advised me of this fact when I enquired on how and where to get the Nomex panels and what the result would be.
We all know that the cost factor prohibits any practical efforts to obtain this stuff and that Podium have a single company specially manufacture their panels to their specifications..............great :roll:
I leave this with you for comment if you like. I've been factual and honest with all here.
I believe that we have come as far as we can go within the limits of a diy panel.
To me it's a speaker that can be used for some music, but fails on a good chunk of others and is dependant on transient severity and power input to survive.
Where to from here?....................................... ....................................... .... :dunno:
jeffac has access to what I believe may be the ultimate CC..........XITEX.
But I must say that even though the thought of a full range panel is very exciting ,I do have problems with the thought of one exciter producing high level sound from say 5 hz to 20 k and beyond ,I can not see it at its best ,it may sound good but is probably going to end in a bang.
Even if I do end up with a large full range panel I would probably roll off the low fs to a sub ,I do not know the answers for everyone but I do know what is best for me.
But that does not stop us from trying!
wonder if it would make sense to have more than one panel for each channel. A large panel for the LF and a smaller perhaps more rigid panel for the HF. From my experience with the few panels I tried the problem if the HF rolloff.
Well, could we try to summarize the info on panels, first the definite points :Thanks for rounding up the main points here ondesx.
- most exciters are to be used horizontally (i. e. facing floor or sky), would they have a shortened life when used vertically ?
my very high power exciter was ordered recentlyThis sounds promising, looking forward to hearing your opinion/results.
I believe that sensitivity is a big issue as they have desperately low sensitivity ratings, but also i suspect that in practice the load it presents to amplifiers is a difficult one - despite documentation that states otherwise :scratch: :roll:
1. use a light,thin foam core board or corrugated cardboard sheet : 5 foot by 2 foot mimimum so that bass will be satisfactory.Coating cardboard helps but can be nightmarish :o
2.use no more than 4 exciters if possible and watch your impedance with paralell/series wiring.
ONE, SINGLE exciter would be best...............until the most expensive and powerful one is purchased and tried, we will not know..................I'm not going there again(see my recent posts).
The Clark Synthesis transducers are ONLY to ''supplement'' stereo speakers. They are primarily ''bass shakers''............................don't forget this fact despite the fact that they state full range audio frequency reproduction :duh:
3, use a reasonably high powered amplifier...........I recommend a good solid state one or a push pull beefy valve job.
5.''one panel stereo''..........WTF??..................what ever turns you on.........
6. panel shape is normally ''RECTANGULAR'' and used vertically
7. exciters are used in a VERTICAL array............not horizontal
9. should the panel be firmly attached to the frame?................in our panels, definately ''NO''.
If you attach the panel edges by clamping them down, you will be entering a different world of DML speakers and require the correct licence and software to pull it off effectively.
Hope this helps. :thumb:
7. exciters are used in a VERTICAL array............not horizontali think you need to re-think your comment re: using exciters wertically instead of horizontally. even if you prefer stereo panels instead of two channels on one board, pol makes a good argument why the exciters arranged horizontally across the short width of a tall panel, and off-center, may prowide better results; seems to me it's worth further inwestigation. go back and re-read his posts...
5.''one panel stereo''..........WTF??..................what ever turns you on.........
6. panel shape is normally ''RECTANGULAR'' and used vertically
7. exciters are used in a VERTICAL array............not horizontal
pol-Can I propose something?
Of course, the sound would radiate out in a slightly different manner because of the difference in footprints - small and round versus narrow and long.
.
I have no idea what frequency ‘s create the impression of slam but the panels do have it in abundance if used in the right way .
The 15 inch unit only goes down to about 40 hz before dropping off fast.
The panel is at a lower level but rolls off at about 25hz.
Zobsky-
I believe "slam" is usually a function more of the mid-bass, as you are pointing out, and also that sometimes cutting off the deep bass gives the perception (false) of an increase in "slam". Is that your observation too, or am I mis-remembering my own speaker systems of the past?
ONDESX
done ... & answered ;))
metal panels
my metal panels are two 11 thou ali sheets [don't know metric]glued together with spray mount,my freind thought this was my best sounding panel so far but it is not as efficiant as cc[at least 6db less].
they are about 2ftx2ft they do not go low say 250 hz .
larger panels do go a bit lower though.
I have spreed myself a bit thin with all these panels.
maybe I should set up a pair as a ref and see if I can get a more efficiant one to sound as good ,its easily said but I have changed these around so many times that I think my heads going to fall off :duh:
I Just remembered I have some 2inch or so styrene panels in my loft :banghead:
I think it has paper on each side ,will this kill the efficiancy of styrene[at least 6db better than anything so far?
oh well hey ho here we go again!
Has anyone looked at the "mission M-cube" a guy on another forum had a set that failed and wanted some help with replacing his setup. Once i looked into his setup i noticed in one of the images this system uses NXT technology.I owned them. I gave them to my father. I go through speakers at an unbelievable pace.
What are they doing here? The little cubes measure 3-4" what is the panel material they are using? How are they getting any kind of decent sound using such a small panel?
Are they using the stands some how to help carry the sound?
In the image, the red part of the cube is cloth that you can change the colors of to match room decor. So is this part of how the sound gets out? Using the front panel as direction, and then the back of the panel to spread the sound outward?
This thing is interesting :drool:
(http://www.audiocircle.com/image.php?id=26854)
So what's happening around here? No one still interested in this technology or are there plenty of experiments going on behind the scenes?Hi Dan,
I am going to try putting an exciter on a hollow body guitar to see how that sounds...maybe a bit louder because of the resonant cavity. Will report after I do this.Cool!, I'm guessing that the hollow body will affect the bass at the very least (helmholtz resonance?), my meagre understanding is that this is how ported eclosures are used to re-enforce bass?.
Over all sound was very pleasant but lacking the highs and lows as with the gatorfoam and the cardboard.Can I just check your meaning here for clarity, the guitar lacked the same H+Ls that the GF and c-board does?, have I got that right?
Thanks for trying that out usp1, seems like it was a worthwhile experiment if it sounded pleasant.
I wish my exciters would show up, I'm itching to play with them.
What were the volume levels like compared with any other approaches you've tried?
Your post (and pols)leads me to wonder if there's any milage in cardboard vessels (I know they've already been done, but I've only heard small/crude single exciter versions like the soundpac speakers).
Could a wood veneer or c/board helmholtz resonator be tuned to re-enforce desired freq's?
I wonder if a larger instrument such as a double bass would help with low freq's in the same way that larger sheets of c/c do?.
I really want to try an exciter on a bass drum.Can I just check your meaning here for clarity, the guitar lacked the same H+Ls that the GF and c-board does?, have I got that right?
I wonder if the lack of highs is systemic to the cheap $5 exciters.
try the second one, down the page
http://img694.imageshack.us/img694/1756/ambiosonic.jpg
two exciters at center (L+R) are very close together
and the two others are at extremes L & R
all that on one single big panel
enjoy...
POL
Im glad someone thought it was funny :duh:There's clearly extreme sports applications for NXT technology which we haven't yet considered!.
What kind of Polystyrene are you using?I'm curious re' this too.
I will, for the last time, state the facts as I see them, of what we are dealing with :roll:..................I agree with most of these points. However, regarding point 3...
...
3. No problem.....we'll just turn the volume up.................NO!!!!..... :duh:..........the exciter will be getting way too much power than it's designed for and will get hot..............so hot that it can melt expanded polystyrene............. as I have experienced :o
Hang on!.............. :idea:............we'll cross them over to a subwoofer..that's it!.................if you think this way, you're better off building a hybrid ELS or ribbon loudspeaker..............lots of posts on that crap :roll:
I have looked on the net but have not yet found a supplier of hi impact sheet styrene,lower grades are not good for full range drivers but these are the only types readily available .
If anyone knows of a supplier in the uk, please could they let me know ?
You would think it would be easy :duh:
sedge
sedge -
Is this the stuff you are looking for? Max thickness seems to be 6mm. http://www.plasticstockist.com/index.cfm?Page=cHJvZHVjdHM=§or=MTE=&Group=NzA=&SubGroup=NzA0MQ==&jump=31
Also on eBay, but only up to 4mm: http://cgi.ebay.co.uk/4-0-x-1372-x-660mm-White-High-Impact-Polystyrene-sheet_W0QQitemZ180478891468QQcmdZViewItemQQptZLH_DefaultDomain_3?hash=item2a056155cc#ht_500wt_754
Dan, ............nope............but you have a good point..............that might stop the ''buzzing'' which seems to eminate from the ''CORNERS'' :o
I'll give it a go and see what happens.
Secondly, PHENOLIC FOAM has a density of 55kg/m3............much more than EPS which is only a few kg/m3(can be more depending on grade, but still much less than other materials).
that's it, an idea to return on the book-shelfDamn, that's not how I hoped it would behave.
POL
I found another set of PE exciters, that makes 15 pairs or 30 exciters in my possessionWould you consider shipping to the UK Jack?
Still $35.00 for the lot, add shipping for USA.
Jack
Would you consider shipping to the UK Jack?
If Jack's willing to ship overseas would anyone else in the UK want to split?
Would you want any more John?[/b]
The reason I specified USA only, was shipping costs. I know nothing about VAT and whether or not it's worth it to someone over seas to purchase a fairly inexpensive item. Can anyone bring me up to speed? I don't know the exchange rate, but aren't we talking about just 16 or 17 pounds? plus shipping?
Jack
I have tried lots of different types of glue and the best one is sold in Finland under the Plastic Padding -brand (Henkel). It is Plastic Padding Extreme Repair -glue. A small black tube with some yellow graphics on it.... I´m not sure if this available in other countries but it is very good glue for this indeed...
The ''high shove exciters'' have a 3 db increase in sensitivity over the standard type.if one exciter is 80db/1w, using four nets 86db/1w. eight gives you 89db, sixteen gives you 92db, etc.. of course, this is for a single speaker - add 3db for a stereo pair.
So, this makes them about 79.6 db from memory.
If you use more than one.......say two pairs paralelled, then series wired, you should get around(theoretically speaking :roll:) 91.6 db.
However, this is all dependant on the material used. Heavy material will kill the output, so the above means nothing.
If your tube amplification is in excess of 25 watts per channe(30-40 watts preferred) and you use VH grade(VERY HARD) polystyrene sheet(very light), you may just scrape it in if you have a big room and like to listen to your music reasonably loud.
In my opinion, they are only good for medium powered solid state.............but that's just my opinion from my experiences so far.
Ondesx
Have you tried mounting your panels vertically on a central beam, such as a piece of 2by 4 say 8ft tall[ceiling permitting ] so that the edge of the panels are left to freely vibrate...
NO SINGLE DRIVER, TWIN CONE(OR NON-TWIN CONE) ''SHOUT'' :nono:
NO SINGLE DRIVER BANDWIDTH LIMITATIONS :nono:
NO HIGH FREQUENCY ''BEAMING'' :nono: :roll:
NO NEED FOR CORRECTIVE NOTCH FILTERS ETC! :duh: :duh: :duh: :duh: :duh: :duh: :roll:
NO STUPID ''SWEET SPOT'' AND THE NEED TO CLAMP YOUR HEAD IN A VICE TO HEAR THE HIGHS AND ''SOUNDSTAGE/IMAGING'' ! :roll: :duh:
NO CRITICAL EXPERIMENTATION NEEDED FOR EXACT AND PRECISE ROOM PLACEMENT :eyebrows:
NO NEED TO ADD SUBS OR WOOFERS TO OPEN BAFFLES TO MAKE UP FOR THE LOSS IN BASS :duh:
NO BOXES AND THEIR DAMNED COLORATIONS! :thumb:
Is 550gm2 it's Density or weight per unit area?
1)You MUST answer these questions though......................HAS THE POLY PANEL INCREASED IN WEIGHT???..........HAS THE EPOXY CAUSED ANY STRANGE ''WOODEN BELL'' LIKE RESONANCES?
2)Also, what did you thin the epoxy with?.............how many coats?............2.... was it?
:o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o
[color=pink!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
[color=red
:shh: :shh: :shh: :shh: :shh: :shh: :shh: :eyebrows: :eyebrows: :eyebrows: :eyebrows: :eyebrows:
foamcore is more of a sponge type foam ,eps is made of little expanded polystyrene beads all stuck together ,the more expanded the beads are the softer the panel.
Would be great to know if zygadr has information in detail about his VH EPS specifications.
My idea is to order the Dayton DAEX25
http://www.intertechnik.de/index.html?lang=de&artnr=1381991 (http://www.intertechnik.de/index.html?lang=de&artnr=1381991)
together with Dayton DTA-1 amplifier
http://www.intertechnik.de/index.html?lang=de&artnr=1381993 (http://www.intertechnik.de/index.html?lang=de&artnr=1381993)
Getting the 5 $ pair of exciters from the US to Germany is probably expensive (shipping & customs).
3 lbs??????????????????????????............what the hell does that mean?
cologner -
If you look back at p.37 you will see some comments by pol_bct about single panel stereo.
I'm afraid that balsa is not the wood of choice.
I had to order 16 2'x4'x 1/2" panels to meet the minimum order
Where are you located? I may be interested in buying part of that order from you...
I just looked at your profile, I bet you are on the other side of the pond... :(
John
I have a small subwoofer for my computer under construction and because it´s so little I´d like to substitute the bass-reflex tube with something else on the back side (similar to "passive radiator"). Maybe a piece of EPS??Not sure if others will agree with me....but....Once you get the panels up and running, you will get a GREAT sounding bass tone that should be more than adequate. The panels I've been experimenting with can produce audible tones down to 30 Hz, with very few gaps (90-100 Hz, 160ish-180ish Hz you can notice some db drop.)
Oh, for heaven's sake...............................I'm out of here.
I, too, prefer Class-D over the Gainclones I have heard...
cologner, with that taste in music, you're gonna LUV these panels!
Hey UK people, if you got your VH grade EPS panels, where did you get them? Can't seem to track it down that easily in 10-12mm format, just fat 25mm for construction industry or small expensive bits for model making.
Cheers,V
Is the panel suspended? If so how high from the floor? Do you have a picture? Does the stereo image have depth? With your single stereo panel can you describe what you hear vs 2 panels in terns of sound stage and stereo image? I would suppose that your arrangement is more coherent. It seems to me that it's interaction with the room would be most important. Can you tell us more about the placement of your panel? If I understand correctly you use 8 exciters, 4 right,4left?
POL,
Interesting post, as always. CC = corrugated cardboard, right? Do you use this as one large flat piece, or is it folded slightly, like say a tri-fold, into thirds with the end pieces folded slightly in or out? Do you think that three similar-sized panels each one one-third the size of your one panel and wired the same way as you have done would work as well, or is there something about having all the exciters on one single panel that makes a difference? Have you tried the material ZYGADR uses?
Interesting, interesting.
Bobloblob
So guys , what about Rohacell ? Yours opinion ?!
Rohacell price only 1,4Euro/m2Assuming what ever USD value you have suggested is reasonable... that is not the problem. The obscene amount they are charging for shipping is.
What's to see? two big white panels in a pine frame.
They work and work very well.
Here's a secret be very very careful what you use to bond the panels to the wood with! remember, lots of constant vibrations are cruel to rubber adhesives tapes etc.
I think it is a fair request ziggy. You started all this and still continue to advise. Yet you refuse to show people the finished product? Seems very odd. It's just a few pictures.
Furthermore, your comment doesn't make a whole lot of sense to me. You have your panels bonded to the wood? I was under the interpretation the goal was to keep the two decoupled. This is why pictures are often more helpful. Then we can see with our own two eyes instead writing that is: sometimes hard to understand, vague, and incomplete.
irishpatrick33-I know. That's kind of my point. Using expensive materials kind of runs contradictory to the whole idea/thread.
search for NOMEX - perhaps it is branded differently in some countries, but that is the name in the US.
Forgot to mention, just in case you had not been following the whole thread, that Zygadr and Sedge are using VH grade EPS (expanded polystyrene) of different thicknesses presently, while POL is using corrugated cardboard. NOMEX, the version with phenolic resin coated paper honeycomb, as used in the Podium speakers. is quite expensive. Judging by the results of others here, EPS works very well and is considerably cheaper.
If you are hoping that the poly sphere will radiate like a pulsating sphere, you are going to be sadly disappointed
Pol-bct
I thought I would wire my 4ft by 4ft panel as a stereo panel ,just to see what would happen
.....
I think I prefer the sound from the large panel ,it sounds cleaner and clearer
.....
As for the one panel for stereo ,if I can order an 4x8 panel and wire it up as a stereo panel
.....
sedge
Actually I'm really intrigued by the foam spheres that Patrick posted. The big ones are $$$, but the 16" could be fun to try. I have a 16" globe, and that's a pretty big sphere. It has more surface area than a 2x2' panel (one side at least.)
Since they are split in 1/2, you could put an exciter in the apex of both and close it up to make a sphere or use them open to hear the difference. It looks like the 16" size includes shipping, over that requires a shipping quote.
Naw.... I don't expect that, being NXT and all. Really don't know what to expect. But it might radiate OK all over the hemisphere with the exciter at the apex. Did you actually try a hemisphere or sphere, or just the 2x2 panel?
Even if a 16" doesn't do much bass, it might make a fun mid/hi driver.
Panels and rooms
.....
Any(sencible) Idea’s are welcomed.
sedge
Results to follow.Alright, so it appears as though my cone EPS speaker was producing surprising bass because of the driver--kinda think the cone EPS sucks now. The Dayton 25mm high shove variety is certainly more adept at delivering the bass. (1) high shove vs. (4) cheapies seems to be a fair comparison. The (4) cheapies can play a little louder/efficient, but the high shove seems to provide more potent bass.
...
The spot 30% from the top of the panel seemed to perform best, especially in a critical areA such as bass. 60% down from the top also was a good performer.
....
I don't remember reading about your stereo panel - what did I miss?
Thanks Bob! I thought I had been following this thread, but seem to have missed a lot.
Interesting setup POL. BTW, you're Francophone?
Try ''PROPER'' (not the Chinese knock offs) cloth tape. You can tell that you have the right tape by the canvas look pattern it has printing through.I have no idea what this means. Are you securing the panel to the wood frame with this cloth tape?
Tape all edges around the perimeter of the panel and stretch while sticking down on to a frame or opening in the panel that will give you approximately 1/2 inch clearance between panel and frame.
This will damp any unwanted resonances at the edges of the panel.Only one side of the panel needs doing.
Rounding off the panel corners is not required.
I have no idea what this means. Are you securing the panel to the wood frame with this cloth tape?
Try ''PROPER'' (not the Chinese knock offs) cloth tape. You can tell that you have the right tape by the canvas look pattern it has printing through.Sorry to bother again. I am not sure I know what kind or brand of tape you are speaking of. Could you provide a link, brand name, or something? Is it gaffer tape?
It looks like the latest refinement is to omit the wooden back brace to support the exciters, and just stick them on with 3M double sided tape. Is this correct? Can the 3/8" EPS support the weight of multiple voice coils? Is the back brace detrimental to the sound?
However, the use of glue is quite acceptable providing it does not react with the panel material or exciter foot.I assume Crazy Glue would qualify. Correct?
If you are going to use glue, make sure that it dries ''HARD''!..................any softish or mushy drying glue will kill the coupling and the much needed resonances required to transmit from the exciter to panel...............this is CRITICAL ! :nono:
This is a shellac with titanium dioxide in it. If you want white, this will do. Titaniunm dioxide us the white base pigment you see in latex paints, and is the whitest of commonly used pigments. This primer will probably dry to a matte finish. Most other finishes will go over this well, which is why it is used as a primer.
Check for a date on the can, as older shellac does not dry as well or as completely as fresh shellac.
Might be sorth saturating the cardboard as much as possible with regular clear shellac first, then overcoating with this product. Shellac is a spirit-based finish, so there is no need to sand between coats except to get a smoother surface or to get rid of irregularities. If you do use clear on your first coats, try thinning the clear shellac by half or more so it has a better chance of penetrating some. Work quickly as shellac dries fast but will disturb the previous coats when you work over it too long. Whatever technique yo choose, test on a small piece first to make sure you will get the outcome you want.
I now know how the inventor of the PLANOT speaker felt as he got blasted to bits by the diyaudio crowd...............they're a fine lot!
Not a good comparison. I had to buy expensive low resonant material in much higher quantities than needed, had iron lasered, built a star-shaped structure that is much less resonant than the long bar and measured a 20 dB decline where the cancellation should happen in theory, so the talk about Moebius strips in the air is nonsense. On the other hand nobody doubts that NXT technology works.
This is a shellac
....................
Might be sorth saturating the cardboard as much as possible
....................................... ....................................... ..
While you are doing this, have you thought of trying POL's format? Might be fun to compare while you are doing all this too, especially since it would be easier (not to mention cheaper) to test out on CC. For test purposes, it could even be done before you treat the CC, just to compare the separate panels with the one large stereo one.
This has been some journey for you, hasn't it? Sounds like the results have really been worth it for you - and for the others, too.
> There is just one size available - 90 x 60cm.
nice, but small,
it's a very different experience to listen to a medium size panel
and to listen to a big one, surface of radiation is everything...
http://img218.imageshack.us/img218/7919/p261010alainltc.jpg
POL
Another try could be:
http://shop.strato.de/epages/15452660.sf/de_DE/?ObjectPath=/Shops/15452660/Products/902190_11/SubProducts/902194&ChangeAction=SelectSubProduct
Which kind of damping did You use ?
Hello there,
This is my first post here, and I'm glad it's in this wonderful thread.
First of all I'd like to thank all your contributions. I've learned a lot. Here are my recent experiments about these little excitors and big panels:
My 2nd trial with CC (in front of my previous system):
....................................... ....................................
....................................... ....................................
Already long, more later....
...
this is the magic of DML, on a big panel you can walk in front or put anything you want in the way , no serious obstruction
POL
Hmmm... I'm not quite sure about that. Maybe my panels are not big enough (!!). When my wife is standing in front of one panel, some sounds are indeed blocked. It's audible, clearly enough.
Two things I should add:
1) She's not fat at all :lol:
2) The blocking effect is indeed much less than other type of speakers, especially those smaller ones. More sounds are travelling through, no matter how.
...
BTW, I got another special feeling, about its natural presentation. My kitchen is open to living room, in a single space as a whole. When I'm doing the dishes (yes, that's my job :oops:), with the water running, I still can hear pretty good details of the sound.
It's odd. The sound of the tap water is quite a loud broad band noise and can usually cover a lot of other sounds. But not on DML panels ! (?)
Also, the sounds from these DML panels seem more immune to other type of environmental noises. The music is just flowing through. It's not the higher loudness fighting against and suppressing the noises, it just becomes one of the sounds, naturally. Of course there'd be inevitable some loss in the most delicate small details, but generally the playing music stays listenable to a much greater extent compared to other type of speakers.
This didn't happen in my previous speakers.
Is it because of the big radiating area?
BTW, I got another special feeling, about its natural presentation. My kitchen is open to living room, in a single space as a whole. When I'm doing the dishes (yes, that's my job :oops:), with the water running, I still can hear pretty good details of the sound.
It's odd. The sound of the tap water is quite a loud broad band noise and can usually cover a lot of other sounds. But not on DML panels ! (?)
Also, the sounds from these DML panels seem more immune to other type of environmental noises. The music is just flowing through. It's not the higher loudness fighting against and suppressing the noises, it just becomes one of the sounds, naturally. Of course there'd be inevitable some loss in the most delicate small details, but generally the playing music stays listenable to a much greater extent compared to other type of speakers.
This didn't happen in my previous speakers.
Is it because of the big radiating area?
...
The panel is some kind of PS foam, I'm not sure it's extruded or expanded. I'm lost in all those material names you guys mentioned. The material of my panel is usually seen as the base of various posters, or used as wings/bodies of those very light model planes...
It's 182 x 91 cm per panel, 5mm thick, very light and soft and can barely stand up straight by itself.....
...
However, I have discovered a method to stiffen the EPS so that the panel does not flop around and bend all over the place!!! :nono:
It now acts as a rigid, giant peice of EPS without gaining any significant mass..............still extremely light.
...
Hi,
I sounds promising, and so intereting. Is it cambered surface? Like this?
http://www.teragaki-labo.co.jp/products/about_terra-sp3000.html
I found this on the web. :green:
cls
sounds like a panel zygdr tried some time back ,I think he said the panel had poor LF
sedge
Ok Ziggy you have again set the hook. I have chased panel materials and attached exciters coated CC ect and enjoyed the whole process. I use them in my classroom the the students are my test subjects. Younger ears better ears. We have also built the Peter Dainels Gainclone kit and the students can not believe the sound we get from our styrofoam speakers as they call them. Let the cat out of the bag as school will be out soon.Hi Hubert, sorry for not replying earlier.
Thanks Hubert
the 4x4ft panel with damage from windy car park :duh:
But rigidity is a relative term. Nothing is absolutely rigid.
The speed of sound wave propagating along the surface of certain type of material is constant. So, when the frequency goes up, the wave length goes shorter. Up beyond a certain point, inevitably, there'd be several bumps and dips on the panel.
How many bumps and dips is optimal for 'distributed' mode? While this is varied with frequency range and type/size of panle....
Hi
after struggling with double side tape, who does not stay very long in place
I am now using neoprene "colle rapide" SILEA, It needs a long night of rest before
turning the amplifier on, but it sticks very strong transducer and panel together.
POL
.... Were you thinking along those lines when you did this? ....
Here's the pics I promised months ago.
...The modal frequencies are determined by many factors, the primary ones being the material, size and shape of the soundboard, its thickness and grain direction, and also the material, dimensions, and placement of its ribs. Secondary factors include the characteristics of the rim or case to which the soundboard is attached. In general, the thicker the soundboard, the louder the piano but the less the duration of its tone. Soundboard design is often a compromise.
Jackman-
There is a major fly in the ointment with using a musical instrument as a reproducer. Musical instruments all give their own colorations to sound, which is what makes them sound different from each other, and why one chooses one particular instrument over another. This is why, using steel strings, a piano does not sound like a guitar does not sound like a mandolin does not sound like a banjo, and why brass instruments made of the same materials all sound different from each other. The very purpose of them is to add a particular color to the sound they produce.
This is the antithesis of a musical reproducer, which attempts to add as little of itself as possible, so that the sound coming out of it represents as closely as possible the sound that was recorded.
The bridge on a guitar works in fundamentally the same way as one of these exciters does. It transfers the sound of the plucked string to the soundboard and resonant chamber of the guitar. Likewise the bridge on a piano soundboard. On a solid body guitar, you have Peter Frampton, who sang through the guitar. A fun thing to listen to, but it was not intended to sound like his voice. Most likely if you mount an exciter to a guitar the music will sound a lot like musical instruments played through a guitar, which could be weird indeed. And where you mount it will affect the sound a lot.
This could be fun to experiment with, but I don't think the result will be a very close match to what you are feeding into it.
On the other hand, NXT says that you can put advertising on the front of the panels, so I don't see why you could not do the same with these wither by painting or by mounting pictures/posters of your choice. Depending on how it's done, it may or may not affect the sound very much. If this is just for an office system to have fun with, it may not matter that much. I think you will have to look beyond this forum for thoughts on that, though. I have seen some pictures and suggestions elsewhere for this, but can't remember where.
....
In this page (http://www.speech.kth.se/music/5_lectures/conklin/howdoes.html), I saw interesting comments on the tradeoffs:Quote...The modal frequencies are determined by many factors, the primary ones being the material, size and shape of the soundboard, its thickness and grain direction, and also the material, dimensions, and placement of its ribs. Secondary factors include the characteristics of the rim or case to which the soundboard is attached. In general, the thicker the soundboard, the louder the piano but the less the duration of its tone. Soundboard design is often a compromise.
For what its worth, spruce is the choice for piano soundboards because it is relatively straight-grained and is one of the harder softwoods, so there is a consistency of response across the expanse of the soundboard. Also, Douglas fir is one of the hardest softwoods, and most stable of woods, and may be a reasonable choice for experimentation. I don't think either comes in veneers, though, at least not publicly available.
One could use carbon fiber cloth and get both strength and relative lightness, and it is light enough to do more than one layer, but I don't know if there would be any advantage over Zygadr's eps panel. It would also be a lot of work, and messy, and hard to control the outcome in a one-off diy project. And it is probably chasing after something beyond Jackman's modest demands for his project. I like the thinking, though. For a trial, one could buy a small piece of carbon fiber cloth and a bit of epoxy (and here you have to find a hard epoxy - it comes in several varieties, from very flexible to rigid). I'm not so sure that damping is a quality you want in a panel beyond what will reduce any tendency to ring.0.3 mm glassfiber reinforced epoxy boards are very common and easy to get. And resins behave more linear than thermoplastic substances. Phenolic resin was the usual substance for spiders before the war. There are worlds between the Podium with epoxy/aramide and Rohacell (a thermoplastic foam) in neutrality. The Rohacell cost me quite a lot of money, but I couldn't stand the neutrality problems, so the boards went into my garage very soon.
Both have bass....................framed has more bass :green:
to every panel builders,
How far is it from your panels to the rear wall? How do you feel the significance of this? Anyone tried absorption/diffusion on the back of panels?
I'd like to hear your opinions. :)
POL-
I saw the one picture of your panel from the front. Is there any chance of posting a picture from the rear too? I understand basically how you have the panel set up, but a photo is always nice if you can do it.
Any changes to your panel since your earlier description?
Thanks
.....
only one cheapo on each panel, at the crossover point of the ribs:
.....
Preliminary setup, wired by the method mentioned by Pol, with an exception that my center has only one driver:
Pol,
Its VC is attached on the rib at the crossover point by 3M adhesive tape. The feet are also attached on the ribs, but by screws. I thought this is OK since the feet are quite soft, should be compliant enough. And it's just like how it's designed to be used on any surface. Now the surface is the rib, that's all.
I did encounter a problem by such configuration, but I guess it's not caused by the feet, though... I think it's the ribs, or between the rib and panel.
Oh, you didn't answer one of my previous question: securing the transducer by its VC alone (without feet or external frame), would it rock at high SPL?
And about the 3-ch connection, I don't understand. Isn't the center seeing the sum of L&R?
OTOH, a clean enough sub with proper directivity to match the panel is the difficult portion, I guess...Yes, yes. A problem with almost all panel speakers.
....
It is not a self made exciter. ....
Is the only advantage of using multiple exciters for SPL?
I only have a small room, around 8-9ft square-
...
Would one be suitable for lower volumes (I was using the Omnes Audio BB3.AL (Veravox 3) in OB, and was getting enough overall SPL from that (no bass though to be expected.)
Here is a picture of my modified exciter.
(http://www.audiocircle.com/image.php?id=50013)
You could hardly belive it, but it sounds great :D
Kludden
....
I took an 3 inch fullrange speaker, cut off the membran and glued a piece of tube wood to the spool, instead of the membran.
....
He said it's a "tube":
:green:
I'd suggest, maybe it'd be even better to have some venting paths among the VC former, pole piece ... etc. :wink:
How about a lathe, or a big drill bit? :green:
Yes, I know he said it's a ''tube'', but can you find ''wooden tube'' at your local hardware store?????????? :duh: :roll:
Wood would be better because......?
More bass?
I think of cars.
MB with big capacity V8 on Autobahn vs Elise (or Caterham) on country road. :green:
High power vs agility....
Eventually, nothing can deliver perfection in every aspect. This brings us back to multi-way speakers.
That's why I never got rid of my massive three way horn system! :icon_twisted:How does it sound when both are running parallel?
Wood would be better because......?
More bass?
How does it sound when both are running parallel?
If anyones interested, got a reply on the Dufaylite Ultraboard-
Ultra Board 2000 x 600 x 6mm Type : R = £6.33
Ultra Board 2000 x 600 x 10mm Type : R = £7.64
Ultra Board 2000 x 600 x 18mm Type : R = £9.28
2400 x 1200 x 6mm Type : R = 3.11kg (2000x600 = 1.55kg)
2400 x 1200 x 10mm Type : R = 3.41kg (2000x600 = 1.70kg)
2400 x 1200 x 18mm Type : R = 4.09kg (2000x600 = 2.04kg)
Is that particularly good or bad, for 1x Visaton EX60S Exciter per board?
The horns were way better and overpowered them in each case.
It's interesting. Would you please share more about that measurement? :)
And then, what makes you keep the panels?
....
In my opinion, the sound of live music is within the realm of the panels more than horns or any other box or panel speaker. :o
Everyone
While doing the tests on the foamcore I noticed something strange about the hf.
....
sedge
Sure I will :green:
---------
In the last few days, one of my little frogy gets noisy at higher SPL. I finally pulled it off last night and found it's because the mounting ring was off.
(http://i82.photobucket.com/albums/j263/CLS_photos/Audio/DML%20Trial/DSCF0419.jpg)
Did anyone encounter this? Is superglue good for this?
....
It seems to me that as we start to complicate the panel with sticks and braces (myself included), we encounter additional problems and resonances or lack of bandwidth???? :roll:
I have the feeling that by doing this we are farther from DML
and return close to pistonic
POL
This looks good-
http://www.ultraboard.co.uk/
Quick quote is for two panels 2000mm x 600mm with-
6mm @ £12
10mm @ £15
18mm @ £18
Seems good, would the 6mm be too thin/bendy?
Do they need to be 'grounded', for example, the back of the magnet attached to a rigid support or just move in free air? Some people have a support, some dont. Will there be any cancellation going on if its just in free air?
I think i will just get a pair of the Visatons for the moment!
EPS VH is still the King!!!!!!..............long live the King!!!! :icon_twisted: :icon_twisted: :roll: :o :green:
Full details on ULTRA BOARD coming soon everyone! :thumb:
Email just sent to MONACOR requesting application possibility and frequency response regarding the AR-50 exciter!!! :thumb:
Understand. And how boundaries you use, means, borders constrained or free ? Here I read divergences from others users.
Waiting for the exciters to arrive and I will try plywood but thinner, 2 mm I think.
Hi Pol,
It is possible that if the borders are free to move, some increased more distorsion could happen?
I am not sure, but when the corners cuted to 45 degrees the sound was more pleasant. I am wonder if with the borders somewhat attached with soft constraint will improve teh sound quality with less distorsion?
Well all, ..................here are the latest results using new panel material and different exciter configuration.now, you need to mount exciters in the typical wertical ewenly spaced arrangement, so it's an apples-to-apples comparison. :green:
Yesterday, I picked up some 3mm plywood from the local timber supplier. The plywood was labelled ''Premium''........whatever that means?
The sheet size was an odd 1200mm X 820mm.
I attached the four exciters as I said I would according to the Amina loudspeakers photo previously posted.
3M adhesive tape used for all experiments was once again used in this new placement of the exciters.
I listened to digital radio broadcasts of classical music and jazz.
Result?...................WOW!!!!!!!!
The midrange is to die for..............highs are like silk and very pure and definately not lacking.
Now, here's where I was surprised............BASS :..........I have plenty, all the way down to about 50hz.
It is definately not one note and by feeling the panel, there is considerable vibrational forces at work with 4 exciters in the new position at the rear of the panel.
All in all, this sound from the thin plywood is without doubt the finest and best of all panel materials tried.
I'm not sure if the close together/offset exciter placement has something to do with this ?.......it may, or it may not?
The output from the plywood panel is noticeably lower than EPS, but the improvement in sound is well worth the trade off.
If the Monacor exciter turns out to be a winner, I think we have a stunning panel speaker about to emerge!!! :o :thumb:
I would like to connect four per pannel. The exciters are 8 ohm and now they are connected in parallel having 4 ohm at the end. With four which is the best way? Series and then parallel, or parallel then series?? In both cases I will have 8 ohm at the end.
Hi Pol , Zygadr..
Can you explain me please why one way is better than the other? Is confusing having two opposite opinions :roll:
Hi Pol , Zygadr..
Can you explain me please why one way is better than the other? Is confusing having two opposite opinions :roll:
Grab a piece of cardboard, EPS or similar. Place one exciter on the panel and listen. Then place a second exciter, connected paralell to the first and listen again.
by doing this we will probably get above 3 dB, but not 6dB the surface of radiation has not doubled, only the excitation power
Yes, that is kind of what I am thinking too.
.....
provided to me by NXT in England as 79.6 db efficient.
.......
the Podiums measured 89db+(Podium claim 92db) sensitive (with 4 exciters, remember)
.................
How do you explain an increase of 10db as opposed to your ''thinking'' of : 3db?????.
I bought a Vika Amon to try. It's heavy but doesn't sound bad. It is like a hollow door. The frame is particle board 1" wide on the sides and about 6" wide on the ends where legs are attached. I cut 6" off each end and 1" off each side leaving just the surfaces and the cardboard core. Much lighter now and the sandwich stays together just fine. Now it sounds very good. The core material is thin and rigid. I find it an improvement over the 3 mil mahogany ply I tried which was quite good too. I would dearly like to get a hold of a honeycomb paper panel about 1/2" thick and experiment with treating it with shellac etc. My wife is very impressed with the Vika Amon now that it is cut down. The exposed edge looks OK too.
Hi all!
There are some new exciters available from HiWave at Parts Express:
http://www.parts-express.com/wizards/searchResults.cfm?srchExt=CAT&srchCat=634
- the most interesting one is the HiWave HIAX32C20-8 32mm Self Supported Exciter.
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=297-2114
Although it has a power rating of 30W rms I doubt it is the best choice for low frequency reproduction because of restricted excursion capabilties due to its mechanical design. Nevertheless I think it's a big step in the right direction - especially regarding cost effectiveness.
I've also performed extensive tests on the AR-50 during the last months - in my opinion it is no match to the HiWave exciters - soundwise and also regarding sensitivity - however their rugged, waterproof design offers some interesting ways of use.
Another interesting design I came across is the following:
http://usfps.com/mcma-transducers_en.html
The FPS0105HY-02 hybrid speaker seems to be an interesting tool
regards
-m
This is self supporting also, 32 mm voice coil diameter, and long excursion
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=297-224
Good find! I did not recognize this one because it looks the same as the Dayton Audio DAEX32 Balanced Exciter 32mm which has only a power rating of 10W rms. Nevertheless i suspect its suspension system is rather stiff.
@ zygadr:
I would not underestimate those little 11mm exciters - seriously 0,5W rms is not so bad keeping the size in mind - they allow for only 25mm center to center spacing - in a line array arrangement and have 32 ohms impedance - so its possible to wire up 8 in parallel for a 4 ohm total impedance. They also seem to be "balanced" (at least the HiWave HIAX11C005-32/LP 11mm Low Profile Exciter) - this is a big plus regarding reliability and will prevent "thumbling" at higher excursions and hence reduce distortion in comparision to the not balanced ones. Imagine a 1.6m or taller panel with 64 of these exciters in series parallel wiring. This will be as close as you can get to a real continous line source with single exciters - serious side lobes will start in the range above 10khz and powerhandling will be 32W rms in total. Using the right panel properties for these little suckers (quite thin, not too stiff) could improove several high frequency problems in comparision to former designs substatially and also could boost efficiency (also due to less spl drop per distance doubling) so that the power handling capability will be less of an issue. According to my experiments with close exciter spacing it will also bring the soundstage more in front, right in your face because the nearfield is extended not only for the lower frequency range (large panel with several evenly spaced exciters), also the higher ones - remember the very good paper of Mr. James Griffin on Near Field Line Arrays posted some time ago here in this thread. Most of the principles do definitely apply for this kind of transduction althoug the close coupling of the drive units complicates the whole thing a bit. There would be a big difference to an arrangement with just a few exciters spaced about one foot apart. Bass performance is another story - in my opinion the requirements for panel properties for a linear high and low frequency transduction are some kind of conflicting, but this is a matter that could fill a whole new thread of it's own. Anyway - just give it some thought.
regards
-m
P.S.:
I just visited the HiWave homepage and found it interesting that the power rating specifications are not really consistent - see for youself:
taken from the HiWave homepage:
(http://www.audiocircle.com/image.php?id=56850)
and the datasheets:
http://www.hi-wave.com/downloads/datasheets/DS-HIAX25C15-8SF.pdf (http://www.hi-wave.com/downloads/datasheets/DS-HIAX25C15-8SF.pdf)
http://www.hi-wave.com/downloads/datasheets/PDS-HIAX32C20-8.pdf (http://www.hi-wave.com/downloads/datasheets/PDS-HIAX32C20-8.pdf)
http://www.hi-wave.com/downloads/datasheets/DS-HIAX32C30-4B.pdf (http://www.hi-wave.com/downloads/datasheets/DS-HIAX32C30-4B.pdf)
Generally the test methods for the automotive sector are among the strictest ones so the HIAX32C30 which was developed for this use is most likely the most robust one in the field.
Also interesting is that only the maximum mechanical excursion (peak to peak) is specified, not the linear one - so at the given excursion the distortion figures will be quite high. :bomb:
The way I see it is that we MUST mount the above exciter (no choice anyway due to its very heavy weight)to a back spline or supporting brace and then attach the panel to the array of exciter feet.
This way there will be no added mass to the panel and the exciter's voice coil will not be under strain providing the panel is supported in a frame of some sort.
so, I don't know if any of you is listening some metal.that kind of "music" has a lot more problems than compression, imo! 8)
this kind of music has a problem: compression.
f.e:
http://i43.servimg.com/u/f43/17/03/84/13/clip_a10.png
this "thing" causes NXT to clipping sometimes.
does anybody had have the same problem?
Interesting. Is this plastic or??? I would like to know how heavy it is?They just say it is wood fiber and it is light.
You CAN NOT use high powered amplifiers with these exciters and crank up the volume...........they will get hot and fry and/or detach from the panels. This has happened to me so I know.
I have gone back to my horn speakers for some time now and do not listen to the panels anymore.
That does not mean that I have trashed the idea, it's just that until a true ''HIGH POWER''/''HIGH EFFICIENCY'' exciter is made, there is no point in continuing to try to get real volumes out of them.............they just can't do it. :duh: :roll:
ear some "holes"in some frequencys, next to experiment.
Thanks Tino.
I was thinking in a dsp equalisation. I have a MiniDSP system to assemble and test. I believe that it will help a lot for this panels. What do you think?
About clipping, only when is really loud in my case, and the volume is so high that i cannot enjoy the music. I am using a tripath based amplifier, digital of 150 Watts per channel and it works fantastic.
I have some pictures of my panels, i will post them later.
Dont know if better. I had the HiWave from PE and they had same quality reproduction in my panels. But, the Visaton have the possibility to bolt them.
On the images. I added some weight with lead on the exciters. Attached to the panels with velcro to support them vertically . The velcro do not transmit vibrations to the panel and vice versa.
Added some damping on panels to test. Not sure of the results yet, need more test.
O.K............found a local supplier of Phenolic infused paper honeycomb...............big deal!!!! :duh: :roll: :roll:
After a lengthy conversation, the honeycomb material itself is 16mm thick(nothing thinner), not that expensive, but it is flexible :duh:.........quite flexible!
It's only after you sandwich it between fibreglass, carbon fibre, or various metal sheeting that it becomes rigid :roll:..........and much, much, heavier.........too heavy in fact for our purposes.
There is no Mylar coated option as in the Podium speakers which as stated by the reviews, ''there is only one company in Germany that can make these panels to Podium's specifications''.
So, in my opinion, we can as d.i.y.'ers, forget about honeycomb panels for good as it just ain't going to happen I'm afraid. :(
I would suggest that with the high power/high shove exciter I linked previously, we can still experiment with cardboard, and thin plywood as the best sounding materials.
I will be once again looking at coating and infusing the exterior and interior of cardboard sheets with Shellac using new methods to avoid delamination (a problem previously).
As the panel material itself is critical to the tonality of the sound produced, a paper based panel seems to be the logical way to go.
The panels aren't expensive over here either, but once you apply a fibreglass skin, the weight goes up significantly.yes - you need to keep searching for something local. and me personally, i would stick with 1/4" (6mm). re: the weight, it's 3.9oz/sq.ft. that's under 2 lbs for a single panel...
Yes, I could order from the company in your link, but what about freight cost..........I live in West Australia.
Great stuff Abelma!..................will be very interested to see how these go with wooden panels. If they can drive 1/4 inch glass, then wood should be a peice of cake! :thumb:the company i linked also has laminated end-grain balsa wood, which is even cheaper - i wonder how that would sound...
the company i linked also has laminated end-grain balsa wood, which is even cheaper - i wonder how that would sound...
and the carbon fiber would be my first choice, but that's quite expensive - a 48x48 1/4" thick honeycomb panel is $370. but the balsa wood isn't too bad, at $99 each for two 24x48 1/4" thick panels. all this (and the other prices i quoted are for 1-ply carbon fiber or fiberglass; additional plies are more expensive. not sure you would want more, tho, if using for speakers.
doug s.
Have you guys seen these?
http://www.parts-express.com/pe/showdetl.cfm?partnumber=300-387
Yes j gale it is a good contender! :wink:
However look at the specification sheet for the HIAX32C2O8:
http://www.parts-express.com/pedocs/specs/297-2114-hiwave-hiax32c20-8-specifications.pdf
Plus, it is ''self supporting''(no need for spine or reinforcement to avoid voice coil droop), 30W max power handling(on the HiWave website it shows as 20W - 40W !!!) and a 32mm voice coil. 8)
It's BL is 7.8 :drool: :smoke:!!!!!!!
We can't forget that the above exciter is designed for industrial/commercial audio and to drive ''high impedance'', rigid substrates.
4mm plywood IS a ''high impedance substrate'' compared to cardboard or EPS.
Have a look at the now not available exciter that was used in the Podium 1 loudspeaker : notice the resonant frequency and BL : :eyebrows:
http://www.hi-wave.com/downloads/datasheets/DS-HIAX25C15-8SF.pdf
What's a few Khz amongst friends ? :green:
Frequency response for that particular exciter was probably taken through glass or something ridiculously similar.
Low end response and especially high end response is very material dependant.
Hi tino84.
Sensitivity can be made to be quite high if you use the highest power exciters (high shove) and lots of them on a large panel.
Hiwave have NOT responded to my last question..............I would say that because I am not a company intending on buying hundreds of exciters from them that they will no longer communicate with me.
Had a musician friend pop over this weekend to listen to my speakers.
He belongs to and plays with two continental style trios : Accordion, violin and double bass. I have personally engineered 6 of their CD's over the years.
He sat down and listened to a variety of music : classical, jazz, world and some miscellaneous music.
After 60 seconds on the first CD played, I looked over at his expression and nearly burst in to uncontrollable laughter!
When the session was over, he turned to me as said (quote) '' after all these long years of hearing all your different and expensive systems, you've finally done it!..............you are are genius!..........the double bass in that jazz trio is EXACTLY how I hear it each time we perform. Everything is so real.........it's just like a live performance..........no question about it..................how the hell did you come up with such realism from two sheets of cardboard for heavens sake???????????''
He awaits next weekend with great anticipation, wanting to hear Beethoven;s ninth symphony ..........IN FULL! :lol:
On the plastic foot................why not rip one off a cheap exciter?LOL, I did try that :lol: Their diameter is a tad to small for my beginning design. I build the former jig for a 1.00 inch I.D. and the cheapo exciter former is smaller.
Carbon fiber is usually used in sheets, and is essentially a cloth. If you are using a carbon fiber panel, then that is the carbon fiber cloth in a matrix of something like polyester, epoxy, or phenolic resin. In this way it has similar properties to the fiberglass/polyester resin in boat hulls, surfboards, and car bodies. You could vary the properties by varying the substance in which it is embedded. I wouldn't blame the carbon fiber itself for whatever sound characteristics you are hearing. Laying the carbon fiber cloth over something like a thin sheet of balsa and pouring another substance over it - polyester, epoxy, varnish, shellac, lacquer - may give some interesting results - who knows?
Very interesting post Nickolay!
I had visited the links and I'm impressed what they have accomplished.
I think what I find even more validating is their selected panel size that you had posted (60x20x3).
Not in terms of surface area size, but the width and length ratio's. Their panel width is 33% of the chosen length.
For the panels I've been using, I've calculated them (if I remember correctly) based on the "golden ratio".
My panel size is 48"x16". And guess what ratio that equates to be?.... 33%
Not trying to toot my horn :icon_lol: but just reiterates what has been going on in this forum, how correct we have been (as a whole) with certain parameters of this technology, and building them our own ways to satisfy/challenge our individual imaginations.
Question is, how much further can we take it to be more effective and efficient with out breaking the bank!
Peace!
Hi Zyggy ! Quite the contrary. In DIY we are able to make IDENTICAL PANELS much cheaper and even much perfect. We must try !!!
Tectonic panel size 60"x20"x3", and it work from 80Hz
( By my calculation, summary panel diaphragm surface area is about 0,55-0,6m2 )
And now we are experimenting with Rohacell 31 + Carbon Veil laminating
.......tell us a bit more on how you made them and why they are taller than usual?The VC bobbin in the photos are 1.25" tall, from the Foot to the bottom of the bobbin. This will actually be to tall! I'll need to shred off about a .25" from the bottom.
What are you going to use for your magnet system?I will use a Neo magnet for the magnet system. With what I have in mind, each exciter should only require one magnet. I've been considering a .625" Dia. by .25" thick neo magnet, but I'll have to confirm that down the road.
Now........................what's next??????? :)
Just a suggestion, ...................it would be awesome if we only end up needing ONE exciter instead of multiple units. I know that this would mean that the new motor would need to be very high powered and efficient, but it would certainly be ground breaking to say the least!
emailtooaj!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!WOW!!!.......................LOOKING GOOD!!!
Can anyone give me a ball park efficiency rating with say a 30Cm wide by ~42Cm tall single layer of CC and One Exciter, then with additional exciters? I'm trying to source components that will allow me to not have to attenuate a large efficiency difference between the panel and the dipole woofer doing the bottom couple of octaves.Wish I could help answer that John. Since I haven't had the chance to use CC yet, Zy and others would have a better handle on that.
Just my 2 cents. Small panels are a waste of time. A large panel (say 2'x6' minimum) is truly full range. No woofer needed. A large panel is coherent with a sound stage to die for. Big sound and lifelike image and fills even large rooms with believable sound. Nothing like a 12 square ft tweeter, mid, and bass with the coherence that brings. Trying to marry a woofer to a small panel introduces a xover phase differences etc. Forget small and ugly and go for big and beautiful. For Abelma I don't remember any loss of bass with the Monacor config.
Hi Guys !
Please explain (! after your deep explorations and experiments) , what optimal size and form factor shellac treated CC diapfragm for -3db at 35HZ sound ?
DML that mean exciters monacor placement or not ?
Many Thanks !
''The sound of a D.M.L''.................................coming soon 8) :D
I have heard the Holy Grail of NXT!! And it is good.
Last week in Las Vegas I got to hear a full fledged demo of professional NXT style panels, in a pro PA line array. Quite amazing! Even got a limo ride to and from the theater. That's Vegas, baby. :thumb:
They are made by a new company in Seattle Washing called Tectonic Audio Labs. The panels are large, expensive and beautifully made. http://www.tectonicaudiolabs.com
Weigh about 90lbs each, and they were using 3 per side in a array. Each speaker contains 2 DML panles (Distributed Mode Loudspeaker) made of a Kevlar honeycomb cover with a carbon fiber skin- about 5mm thick. Definitely high tech. Each panel is driven my 4 neo motors IIRC. In between the two is a waveguide loaded ribbon tweeter.
The sound was certainly "Different". Very wide, very even, very clean. From girl with guitar music to EDM and Dubstep, they certainly delivered the goods. The system with 3 speakers per side and subs was said to be good for covering up to 3000 people. I would say yes, it probably could. There was a little bit of an edge to the sound, typical of loud PA speakers, that I thought was just the honeycomb panels. Found out the next day that they were running the ribbon tweeter too low, so that's probably what I heard.
Crossover was active and simple, no DSP, almost no EQ. Very clean and clear, and they didn't interact wit the room like conventional speakers. A plus for us pro sound guys is that they are very resistant to feedback. That's a big deal in live sound.
So, the future has arrived and it sounds good. I never thought the NXT panels could sound that good, or play that loud, but they do. If you have enough money. ;)
And I bet there wasn't one hint of "feedback" coming through the panelsNot that I could tell, no. Couldn't hear the panels in the mic at all. Rather amazing. The real test will be lavaliere (clip on) and lectern mics, those are the tough ones.
Not that I could tell, no. Couldn't hear the panels in the mic at all. Rather amazing. The real test will be lavaliere (clip on) and lectern mics, those are the tough ones.
Frank: Exactly. We will be scrutinizing them further this summer. I'm setting up a demo in a large hotel ballroom here in town. It's an acoustic nightmare of a room (200'x200') that we've been fighting for over 20 years - and losing. If these panels can come close to fixing the problem there, it will be a miracle.
I realize that this is not home use, not DIY, no where near cheap. But it's very informative to hear just how far this DML technology has come and can go.
I re-measured the 1/4" boards I have used, and realized that the store measured tolerances probably are not the tightest - one only measured 0.2 in, and the rest was just shy of 1/4". I actually wanted to buy thinner birch boards, but couldn't find any at the local store so I tried some thinner 1/8" oak boards instead. I have also tried some thicker panel sizes with no luck. I haven't tried any other materials, but am curious to hear if anyone has had success with other tone woods used for instruments. Here's an overview of some alternatives: http://www.guitarnation.com/articles/calkin.htm (http://www.guitarnation.com/articles/calkin.htm)
Here are some pictures on my experimental project
Back
(http://www.audiocircle.com/image.php?id=103975)
Close-up on exciters from the side
It's hard to tell from the pic, but there is some velco between the top exciter and the stand it leans against
(http://www.audiocircle.com/image.php?id=103976)
Front
Note that it stands on two nails
(http://www.audiocircle.com/image.php?id=103977)
hello everyone.......just a quick update on my progress so far with 3.5mm birch triplex panels......they sound fantastic!
(http://www.audiocircle.com/image.php?id=105509)
(http://www.audiocircle.com/image.php?id=105510)
They sound particularly good with classical, acoustic music, vocals and drums. bass is certainly deep enough and highs are crystal clear. could they sound better? probably. do they sound good enough to replace my existing setup? absolutely.
If you'd like to see a video of them in action recorded on a smart phone (sound will not be that great from the recording, but you'll get an idea), i can upload a video to youtube.
Thanks to all on this thread, especially Rob (Zygadr).
Hi Rob,
about a week trying to simulate my next single СС panels. I've managed to get all of the CC mechanical parameters needed and successfully fed it to the NXT Designer. It seems the results are more than truthful - there is NO highs.... :lol: Just check out the pic:
(http://www.audiocircle.com/image.php?id=105410)
The simulator's Help uncovers some interesting facts on that problem, will post it later...
Dissatisfied with the highs? Just get rid of that sticky tape and epoxy the exciter finally! :lol:
I wish I had time to try out this method myself, but I'll just have to get to it when I can get to it :lol:
If anyone else would like to give this method a shot... give me a PM and I'll be more than happy to help with some directions/suggestions to what I think would be best to get the optimal results AND help save you some time hopefully. :thumb:
Peace!
Thanks sedge will look forward to it. For Zygadr a word of warning. I have had the same experience and you are right. If you're like me it won't be long before what if or could I get something more if this panel or this exciter etc. Or something more exotic has to be better. I think this sickness of mine is contagious, so be warned. Jim
we must not forget that the inch or so around the centre of the exciter works as a piston and a lot of the hf above 10k comes from here
hi zygadr
you can vastly improve the sound of your panels with a very light coating of pva but it has to be done in a certain way.I mentioned this some years back on this forum but no one seems to have given it much thought,I have an old 40 cm vh xps testpanel in my loft ,I could get it down and test it for you,or do you have any scrap panels you can test yourself and compair with the untreated panels ,the test panel does not have to be the same size as the db output and sound will be very similar above say at least 200HZ if a 40cm panel is used if my memory serves me well.
using any poly panel or foam panel without a light coating will have a lot of self noise will tend to be over bright and have a tendency to sound hard at times,vh xps is no exception.
Steve
GIANT KILLER PANELS PART TWO. (in the music room ,no one can hear you scream…………….with joy!)
Since building the first 18 inch wide panel with one exciter, I have made two further panels, one 2ft and one 4ft wide, all 4ft high and 25mm thick, using two exciters per panel.
The t-amp I was using is rated at 8 watts at 8 ohms, if that.
This drove my hifi News test cd with the sound of BIG BEN striking twelve, to realistic levels,I kid you not! Plus the lovely sound of the clockworks clinking and clonking as clear as a bell…..ha ha .
I am sure the neighbours loved it as much as I did.
So I think I can safely say that these panels are very, very efficient.
To make these panels is very easy, and only takes an hour or two If using a hair-dryer,but the hf will not be good until the glue hardens, this takes at least 24 hours, so be patient.
You could do as I do ,and just hang them from a stand ( cheap up lighters, in my case -best sound for me so far), but if you mount the panel in any other way you must make sure you do not restrict the panel movement in any way, or else you will lose dbs and alter fr. So take care.
The glue I have used for the panels is nothing special. It is just that I had a gallon lying around and it sounded good on other panels as damping.
The 2ft by 4ft is probably the easiest size to work on and you can easily cut an 8ft by 4ft sheet into four to fit in the car,if using a van or lorry 8ft by 4ft max !!!I would love to try this and could use it as a projector screen with a higher quality polystyrene. The panels do not shake around as my metal panels used to - its just a thought,so far!
To damp the panels I used a 50 50 mix of water and pva mixed in a 1 lb (400grm or so?) jam-jar ,this should do 2 panels, a thin a coating as possible so the panel is just wetted, if you use too much glue you could over damp the panel but if it is still under damped you can add another thin coat.
If you are doing this on the kitchen table be warned glue will seep through in places .
The panels should be damped on one side only!!! And this is the side the exciters will be glued on, you can use a hair dryer to dry this coat, 15 mins or so, and when dry, its time to glue the exciters on.
I used undiluted pva for the exciters, using a match-stick to apply the glue onto the foot. Try to get a nice mound of glue on the base and also dab the sides of the foot. Make sure none goes into the voice coil.
Just remembered that I used sand-paper to take the shine off the exciter foot and hopefully give a little adhesion.
I also applied a thin coating of undiluted glue about 3 inches in diameter around the fixing position. Not sure if this helped in any way but that’s what I did.
Also using the match-stick, build up a small mound of undiluted glue around the area that the foot will come into contact with the panel. The glue will shrink and hopefully this will help fill the gaps.
You could use the hair-dryer to start the drying process on the panel and the exciter, before sticking them together.
Using glue that does not shrink, so as to fill in the gaps could be an idea at a later date but the sound would have to be checked.
I also placed a little bit of weight on the exciter to give a good bond, enough to push the exciter foot into the panel without damaging the voice coil.
Dry the glue using a hair-dryer, waving it around from all sides. The exciter will eventually get hot ,very hot, but don’t worry.. If you are a little worried that the panel is getting too hot, you could always leave it to dry over night instead, its just that I only had a couple of hours till dinner and my wife had a gun at my head!
So if you have to move them after a couple of hours keep them somewhere with a flat surface and leave them to dry overnight ,you can wire them up ready but they will not sound good until the glue hardens, probably after a day or two.
If you are using two exciters I found it better to have the connections facing each other (on the inside) but it’s your choice.
While I think about it I hope every one has removed the horrible plastic casing with those stick on wobbly feet, if not you have got problems!
AS for the position of the exciters ,I used a one third up from the bottom and a one third down from the top in a centre line, other spacing’s could give a better sound ,or maybe not.
But this position sounded superb so it’s a good start.
Also I rounded off the corners of an experimental panel which I had used to trial the damping
But can’t say that I heard a lot of difference, my mind was on other things at the time and now they are lying on the chair with the exciters ripped off but hopefully I can try again at a later date.
sedge
thanks jeffac
patent -pending ,that sounds fun,not as much fun as nailing my head to a table :lol:
for years I have coated my panels with pva, but in the last year I have changed the method, which has altered my understanding of the panel
Is the use of multiple exciters a serious compromise towards sound quality?! :oI think you already know the answer, its a pretty reasonable deduction that 1 appropriately-positioned exciter should win on almost all SQ counts except SPL, assuming all other panel design aspects have also been made as ideal as practical. There is definitely an interaction at the horizontal mid-line between vertically spaced exciters that is considerably louder and more distorted on VH-EPS panels, and that for lack of a better description, sounds sour compared to close listening to other panel positions. Luckily once summed with the rest of the panel it doesn't seem to detract 'too much'. Better this sourness not be there though, and minimizing deleterious interactions is obviously one of the primary reasons for the Monacor, Dayton and oldschoolVlad exciter placement solutions.
Rob.
Jesus..........just look at that.....at the bottom.... :o
http://science.wonderhowto.com/how-to/make-paper-plate-speaker-actually-works-for-under-1-0141522/ (http://science.wonderhowto.com/how-to/make-paper-plate-speaker-actually-works-for-under-1-0141522/)
....Guys, I feel now an irresistable desire to play with those wires and magnets...
Ziggy, I swear now I'll find a way how build an ultimate exciter to drive the plywood... :D
A fast look on the market gives me all I need - a lot of cheap chinese neodymium discs and rings. And large steel washers. As for the voice coil, I wound some to repair, isn't a problem. The theory of the perfect driver is simple: the voice coil must be single layered and a whole one must be placed in magnetic flux as stronger as possible. Ok, let’s go….
I have had and still am having a very busy weekend, but have managed to try the new "thruster" 40w Dayton exciters compared to the standard 25 w version.
I must stress that this was a quick 60 second (with the exciter held up to the EPS panel) try as a matter of interest.
Before that even, the new exciter felt a lot heavier than the others and as soon as a signal was connected to the exciter.........I knew that something weird was happening........massive vibration while holding the bare exciter.
The new exciters were packed in a moulded foam/shaped to fit the exciter standard brown box, but was a step up from the usual cheap and nasty packaging of other exciters.......this time there was an air of class about it.
As soon as the "thruster" touched the panel.................................. :drums:
So how does it sound?These exciters may well redefine the efforts of this very specific, and specialised community of panel loudspeaker builders!
Zygadr
Sorry ,you miss understood what I was saying ,I was not talking about roughness but hardness,the vh eps that I have was cut with a hot blade I think , which melts the surface and forms a hard plastic skin .
I think jeffac says his panels were cut in a different way ? As he says his panels have a soft surface , obviously this makes a big difference to the sound,so maybe we need to know how it will be cut before buying and save a lot of work softening the surface(removing the hard plastic skin).
Hope I have made myself clearer.
Steve.
Hi, All I can say is listen to Sedge! whichever poly styrene panel you are using EPS or extruded sand the surface off on both sides and the edges too. You will be left with a surface that has a velvety feel, but more important the plastic sound will be gone. jgale
Wow. First quick test with the EP exciter and this is something completely else as already pointed out. Massive force and sound. Keep in mind that my other exciters are the cheap ones with legs (which now have been removed), but so far I'm really impressed. This new exciter played louder than 4 of my old ones! Will mount it properly later this week and report back. JD
Btw, I asked parts express about the diff between 32U and 32EP but didn't get too much info:
"It is a new product and Dayton has not published the spec sheet in our website format yet. It should be up in a week or so. The FS for the DAEX32U-4 is much lower 160 Hz compared to the FS pf 395 Hz with the DAEX32EP-4. That is the main difference between the two that I can see. "
Hi OB newbie
I hear the same as you in the bads, but is it not the DML that sounds this way ?
If you want to stop theses panel sing from the rear, you can maybe damp it with some acoustic foam
(like the one for speakers) but i think you'll probably loose some output SPL
Here's some explanations from the creator of the podium sound panels:
"Natural sound manifests two types of sound-waves: binaurally correlated and binaurally de-correlated waves. Binaurally correlated soundwaves are highly coherent, and among other things, permit us to determine where a sound source is located. Binaurally de-correlated soundwaves are highly incoherent, and among other things, permit us to estimate our distance from the source, or the nature and size of an acoustic space. The main problem with loudspeakers is their inability to propagate sound with both wave-types. This is an engineered limitation inherent in the mechanical nature of the devices themselves. Conventional cone loudspeakers propagate longitudinal waves. Longitudinal waves are highly coherent and binaurally correlated. Resonating DML type loudspeakers are transverse wave loudspeakers. Transverse sound waves are highly incoherent and binaurally decorrelated. It is simply impossible to propagate transverse waves with a conventional loudspeaker and conversely, it is impossible to propagate longitudinal waves with a resonating panel loudspeaker. No amount of DSP, loudspeaker placement, room treatment or other adjustments will change this simple fact. To reproduce natural sound, both types of loudspeakers are required.
Layered Sound is the term used to describe the process of combining a conventional and a distributed mode loudspeaker, to produce the same audio signal. This combination, when used in the correct configuration, delivers to the listener sound that is clear, spacious, better imaged and more pleasant to listen to
The correct balance between direct and reflected sound is very desirable. When we listen to acoustic instruments in a concert space, we hear a blend of direct and reflected sounds. This combination creates the immersive effect we all enjoy and instinctively recognize as a natural sound. Unfortunately, conventional loudspeakers do not provide good reflected sound due to destructive interference and DM loudspeakers do not provide good direct sound due to their diffuse nature of transmitting sound. Not every loudspeaker is ideal for generating both direct and reflected sounds. However, conventional loudspeakers are well suited for direct sound and Distributed Mode loudspeakers are well suited for reflected sound. By combining these speaker designs according to the principles of Layered Sound, air disturbance patterns are created that physically emulate the sound waves of acoustic instruments, a natural sound. As a result, Layered Sound provides smooth diffusion, clarity and depth in any size room."
so for him,
with our brain and ears,
DML is useful to know the position in depth of a source in a room and give the room infos
pistonic speakers are useful to know the panoramic position of it in the room
hope this helps
OB Newbie
It's fun, isn't it? I'm new to it as well but here are some thoughts.
Are you using the Owens Corning Foamular insulating sheeting boards with the pink panter? I picked up the the 1/2" thickness R-3.0 from Home Depot labeled XPS insulation, film-faced insulating sheeting a few weeks ago. I havent had a chance to prep one with pva yet as many in the thread recommends, but after I read your note I tried just hand holding one exciter to the board. Keep in mind that the one I have hasn't been cut down in size yet so its 8 x 4ft. And yes, I also hear the hazy and flat sound you describe, which is very different from the clear and "vivid" sound I hear using birch plywood. I also want to get the good EPS sound I'm reading about so I'm curious to follow your efforts to see if similar boards can easily be bought in the US as well.
Using other panel materials I have found that I like slightly larger boards to get some lower frequencies. My 4x3ft panels go to about 60Hz before dropping, but unfortunately only 12k on the high end. Maybe it will be better once I run only 1 exciter vs four. I really wanted a square panel to work out for the look, but it didn't work out for me.
I like to get the panels off the ground and put two spikes (=nail with round head toward floor/stand) to allow them to move more freely and still support the weight. I found this to sound better in my set-up vs standing straight with the whole bottom edge on the on floor/stand. I also have velcro on the back of one of the exciters holding it in place on the panel stand. The only problem is if the music has really deep bass I get too much vibration so I need to put in a high pass filter.
Btw: Anyone has some good tips what's the easiest way is to put in a high pass filter?
I like the stereo image better if I step back a little bit from the panels- maybe 12ft (haven't measured) and have the panels toed in just slightly (not much at all)
Hi OB newbie
I hear the same as you in the bads, but is it not the DML that sounds this way ?
If you want to stop theses panel sing from the rear, you can maybe damp it with some acoustic foam
(like the one for speakers) but i think you'll probably loose some output SPL
Here's some explanations from the creator of the podium sound panels:
"Natural sound manifests two types of sound-waves: binaurally correlated and binaurally de-correlated waves. Binaurally correlated soundwaves are highly coherent, and among other things, permit us to determine where a sound source is located. Binaurally de-correlated soundwaves are highly incoherent, and among other things, permit us to estimate our distance from the source, or the nature and size of an acoustic space. The main problem with loudspeakers is their inability to propagate sound with both wave-types. This is an engineered limitation inherent in the mechanical nature of the devices themselves. Conventional cone loudspeakers propagate longitudinal waves. Longitudinal waves are highly coherent and binaurally correlated. Resonating DML type loudspeakers are transverse wave loudspeakers. Transverse sound waves are highly incoherent and binaurally decorrelated. It is simply impossible to propagate transverse waves with a conventional loudspeaker and conversely, it is impossible to propagate longitudinal waves with a resonating panel loudspeaker. No amount of DSP, loudspeaker placement, room treatment or other adjustments will change this simple fact. To reproduce natural sound, both types of loudspeakers are required.
Layered Sound is the term used to describe the process of combining a conventional and a distributed mode loudspeaker, to produce the same audio signal. This combination, when used in the correct configuration, delivers to the listener sound that is clear, spacious, better imaged and more pleasant to listen to
The correct balance between direct and reflected sound is very desirable. When we listen to acoustic instruments in a concert space, we hear a blend of direct and reflected sounds. This combination creates the immersive effect we all enjoy and instinctively recognize as a natural sound. Unfortunately, conventional loudspeakers do not provide good reflected sound due to destructive interference and DM loudspeakers do not provide good direct sound due to their diffuse nature of transmitting sound. Not every loudspeaker is ideal for generating both direct and reflected sounds. However, conventional loudspeakers are well suited for direct sound and Distributed Mode loudspeakers are well suited for reflected sound. By combining these speaker designs according to the principles of Layered Sound, air disturbance patterns are created that physically emulate the sound waves of acoustic instruments, a natural sound. As a result, Layered Sound provides smooth diffusion, clarity and depth in any size room."
so for him,
with our brain and ears,
DML is useful to know the position in depth of a source in a room and give the room infos
pistonic speakers are useful to know the panoramic position of it in the room
hope this helps
+1. So called pin point imaging that some are so fond of is unnatural.It is never heard in live or real music. Having said that I can understand the fondness for it. I like the effect too, but since it is not natural we should not be critical of the panels for not giving us this unnatural feature. If we are honestly looking for close to a real listening experience the DML panels come closest and with the greatest clarity. How the reflected sound is managed becomes very important. My own room is long and fairly narrow. With the panels toed in about 45 degrees about 30" from the back wall (closest edge) and about 18" from the side walls I get a strong centre image. A vocalist sounds very real. My room is fairly lively. I realize that reflected sound is dominant in producing the experience, but then it is at a live event too. Coming from monkey coffins or horns the panels take time to get used to. I think it takes time to let go of the flaws that we are used to. With the panels I find that I listen to the music instead of listening to speakers. When properly set up the panels are almost unnoticed. Sedge mentioned a difference in presentation between small panels and larger ones. In my opinion 2'x4' is about the smallest size that is useful and then only if something else handles bass. The bigger the panel the more realistic the listening experience. Playing with panels smaller than 2'x4' is a waste of time--again my opinion.
Got a couple off home improvement projects I need to complete before experimenting more with the panels. I still suspect the muffled sound you are hearing is the xps board you are using. I wonder if some shellac or something similar would help. ?? At least that is what I will try when I have a chance.
OB Newbie, firstly, don't think for a second that a DML will act like laser beam death rays at high frequencies and provide pseudo acoustic imaging tricks that so many audiophiles just can't live without despite all their direct radiator shortcomings.
I find it strange that your attempt at DML 's produces a sound that is ''veiled'' (??????) and ''flat'' (?????). There is something amiss there as DML's are the opposite to this in my opinion.
Also, you are using a SQUARE ( :nono: ) panel that is very thick and run by a more or less average exciter.........probably not a good match? Your room size, together with their positioning within that room, will also have a great effect on how these panels work.
You say your panel material is pink, and others have mentioned blue?? :scratch:.
I came across the light blue stuff recently at the foam supplier and can say that it is definitely NOT the same stuff as VH GRADE EPS that I have been using (it was named ''XPS : SOVIRA BLUE''???. I don't know if this other stuff is what is causing anomalies out there, but I wouldn't be surprised. It is definitely NOT ''EPS''.
By the way, the sound DOES come from the back of the panel.......it is supposed to and is what contributes to the magic of panel speakers.OB speakers that are primarily forward firing, are a different ball game, so forget about comparing the two systems and concentrate on improving the DML's.
Once again on the subject of wide versus narrow panels to improve imaging.................you are not dealing with shoe box speakers on stands............the width of the panels do not act in this way (thank God! :roll:).
May I suggest you read ALL of the reviews found on the Podium website(as well as comments throughout this thread) so that you can fully understand that the DML is the only speaker type that can do what other speakers, including panel types, just can not. This is especially evident when compared to the sound of live music, which is what we audiophiles strive for. :)
Rob.
Yes, ............but as far as I know, Podium have never released a "layered sound" loudspeaker.As a guess, they probably had significant trouble making it work due to the two totally opposite technologies and the sound they produce.
Having attended numerous symphonic concerts, I have never noticed "imaging" as a real event occurring on stage. What I have noticed is the diffuse and homogenous sound field with lots of reflected energy (I actually heard the Tuba notes reflecting off the concert hall roof!!!)and some direct sound..........very similar to the effect of a DML in action.
Hi Ob Newbie.
I have mentioned once before that I had a forum member from overseas visit me to hear my first version of the DML's when I was using black Gatorfoam.
You talk about "dynamic contrasts"????........ :lol:........when I played a percussion blast from a CD I have, he nearly fell off his seat!........and so did I!
Instead of listening to rock music, borrow some real audiophile cd's of a different nature to hear what this technology can do. Listen to Yo-Yo Ma's "SOLO" (cello on it's own in a fantastic open acoustic) to hear dynamic contrasts and imaging. You want details to pop out at you?.........it's all there and every time I listen to it, there is something new to discover and it is NOT "spotlit"........that is unnatural.........more "hi-fi" than "real-fi".
Anyway, I don't mean to create arguments , but there is a lot more going on in a DMLthan first meets the ear :D
Hi, For you guys that have only recently started experimenting I want to pass on something that I have learned. Over the years of OB's, horns, and others you learn quite a bit about what works well and why. That body of knowledge tends to close your mind somewhat to possibilities you might try if you didn't,t have that knowledge. I have found that what you think you know often doesn't apply with these panels. Since 2009 my assumptions based on knowledge built up over 40 yrs. have been shot down over and over. These panels don't play by the rules, so sometimes it pays to try things that you KNOW won,t work because with these sometimes it does. One EG., EPS . I always ended up rejecting it because of It's plastic sound. I thought I knew that any coating would not change it enough to satisfy me. It took me 6 years to get over my ignorance because of what I thought I knew.
Jgale
At the moment I am revisiting some of my older panels to see how they perform with the new sanding and pva method,as I type this I am listening to the new pink Floyd album (an Xmas present)on a 3mm thick 12x9 inch partially clamped panel it has a good response above 250HZ and very flat above 2.5k to 20k and this is only being held together with tape and g clamps ,I have them sitting on top of an old pair of Ditton 44s but just using the 12 inch bass units xo at 300HZ, I usually let the panels run down to about 100HZ, I would just like to say I am not championing small panels I am just saying that they do work and that if you have a small room and the other half does not want a 6ft panel you don't have to loose out on the panel sound.
As for the presentation of the sound from the large and small panels,having a large panel in a small room IS like a massive pair of headphones, and if you switch between your headphones and the panels they should (if done properly ) sound very similar.
With the small panels in a small room you will hear more depth and space around the panels and a little more delicate sounding maybe ,but you will not (as yet) get the full shock and awe of the larger panels.
The small panels do sound good with drum solos ,better than most speakers I have heard ,but they just can't match the shear scale of the large panels ,swings and roundabouts again I'm afraid.unless you can get an OB to do the same but then your getting into large panels again.
OB_newbie
If you would like a little more presence from the front of your 25mm thick panel I would suggest you try my method of sanding a cone type shape on the front side of the exciter of about 2inches wide and leaving about a 5mm thickness to the exciter,this gives the panel a more detailed and intimate sound ,I have mentioned this before on this site but maybe you have not read through all the pages,things tend to get lost in all the posts .
Steve
AMEN!!!!
Hi Ob Newbie, gosh yeah!.....those Telarc AND Reference Recordings are something to hold on to forever!!!!
The absolute most INCREDIBLE, MIND BOGGLING, SUPER FANTASTIC percussion recording I own is :
''PERCUSSION XX''.......Jonathan Faralli........''ARTS'' label : 47558-2 ''audio Phile series'' 24/96 recording.
If any of you out there can get hold of this recording, you WILL BE BLOWN AWAY!!!! :o :o 8) 8)...............but beware!!..............so might your speakers!!!! :green:
OB_Newbie, I am presently using 2'x4' panels with 15" Augies in an H frame. The combination works well. The 2'x4' need the help on the bottom. When I used 30" x 60" cardboard panels they didn't need that help. Neither did the similar sized birch panels I had. To my ears some form of OB bass is the way to go if the panels need help, U frame H frame etc seems to blend better than sealed subs or similar.
One easy way is to just suspend them with a couple of elastic bands. For my 2x4 panels I cut a 16" circle to sit on top of my H frames, attached a 1x3 frame, narrow edge toward the panel about 15"x48" so that it doesn't show. I put short screws into the back side of the panel 1" below top edge 15" apart, 2 more near top of the frame (longer screws) small elastic band about 1" in diameter lets the panel hang free and nothing shows. EPS is so light that not much is needed. Even the speaker wire holds the panels from swinging. Several ways of doing it are shown in this long thread. I prefer not to restrict the movement of the panels. I have in the past attached them to a frame using pieces of foam backer rod which did restrict movement a little but it didn't seem to be a problem. I haven't worried much about a permanent arrangement because the experimenting becomes an addiction. My wife is used to it and likes the sound of the panels too. Rich I think your chances of staying off the shit list are slim at best. It sounds like you are getting hooked too.
My 2'x4' panels are 3/4" thick. It's messy but sanding off the surface skin left by the hot wire cutting and Sedges PVA treatment will drastically improve the noise of your big panels. They will sound much more natural as well. That skin has to go if you want to hear what these are capable of. Just coating them as is won't do it.
OB Newbie - still like your XPS panels? Are they worth a try or is the muted sound still there?
The birch panels are only $10 each and the 4 X2 at home depot are similarly priced (and if you don't cut or sand on them they can prob be returned if they don't work out).
There were some more details on the different EPS vh equivalent grades availavle in the US on pages 52 and 53 but I wasnt able to find a conclusion (ran out of time). I also think some people use hard eps for surfboards.
There were some more details on the different EPS vh equivalent grades available in the US on pages 52 and 53 but I wasnt able to find a conclusion (ran out of time). I also think some people use hard eps for surfboards.
I hear you on the voids. In regards to the special wood store I found the quality was much much better and I was surprised with the low price... but maybe it is the voids that make it sound better ??? Will try to braze the thinner panels. Back to the EPS hunt
Has anyone tried foil-faced poly isocyanurate board? I haven't looked at specs but it seems to be more rigid than XPS and lighter. Commonly available in the US in 1/2" to 1" thicknesses....
Yes, I had some larger scrap pieces at home several months ago. I didn't know about the re-skinning method at the time so I only played them as-is. They didn't sound good in stock condition - very muffled - kind of like you would put a pillow over a speaker. So I abandoned it quickly. But perhaps Sedge's trick will make them sing. I don't have one at home to try.
VH EPS AND "THRUSTER REVIEW"
Thrusters are mounted in number one position as per Monacor placement /recommendations.
First thing that becomes immediately noticeable is the significant increase in volume/efficiency of these new tech. exciters!!!!
Second is the fact that the VH EPS available here in Western Australia has no "skin" ..........it just has a finely textured surface that has no shine or anything that I can tell that resembles a surface that needs to be sanded and replaced by PVA glue.
Third point is that as expected- the 6X2 sheet at 20mm thick is far, far more rigid than standard EPS at the same thickness.
The sound is very interesting to say the least.
The speakers totally disappeared as each track or radio program changed. However, never once was there any question as to what was in the left channel, centre or right channel.
Depth was truly amazing, as was the obvious acoustic venue or closed in studio miking which plagues so many recordings.
"Dynamics"?.........WOW!!!!!.........absolutely the best I have ever heard from a DML!!!.......don't know if it's the thruster exciters or the more rigid panells? The PERCUSSION XX recording mentioned in one of my last posts is jaw dropping..........different!......strangely so.....very weird, yet so compellingly REAL!!!
Top end is very natural but not as fierce or prominent as the thinner EPS with standard exciters. Only burn in time will tell if this area changes or not as it could be the exciters or, once again, just the fact that a thicker panel is being used?
Detail?.............it's all there........trust me.
Mid-bass?.........lots of tonal colours and contrasts........truly outstanding, massive dynamics as already mentioned.
Low bass?........ Jury still out on this one.........panels are free standing and not mounted as yet.
Rob.
Local speciality lumber store in Indianapolis that carry a lot of different kinds of wood (including many excotic hardwoods), plus they are super nice and helpful (even had some suggestions when I mentioned what I would use it for). I'm guessing there must be similar lumber stores in most major cities
http://www.northwestlumberco.com/ (http://www.northwestlumberco.com/)
Apparently I have way to much time on my hands (Xmas break is wonderful) :-)
* The distant and veil sound is back and even worse than I remember with the small panels. I thought that the small panels were improving but had also honestly thought that I have just been adjusting to DML panel sound.
But I can very confidently report that the wood glue:water mix after it hardens is a miraculous and very clear improvement. How much is attributed to the exciters breaking in is unclear. Bottom line, the difference is *significant*.So if I'm understanding this right, the thicker but larger XPS panels still sounds a bit "muted" and that the re-skinning improves the clarity but doesn't take it all the way on the particular panel you are using.
VH EPS AND "THRUSTER REVIEW"
Thrusters are mounted in number one position as per Monacor placement /recommendations.
First thing that becomes immediately noticeable is the significant increase in volume/efficiency of these new tech. exciters!!!!
Second is the fact that the VH EPS available here in Western Australia has no "skin" ..........it just has a finely textured surface that has no shine or anything that I can tell that resembles a surface that needs to be sanded and replaced by PVA glue.
Third point is that as expected- the 6X2 sheet at 20mm thick is far, far more rigid than standard EPS at the same thickness.
The sound is very interesting to say the least.
The speakers totally disappeared as each track or radio program changed. However, never once was there any question as to what was in the left channel, centre or right channel.
Depth was truly amazing, as was the obvious acoustic venue or closed in studio miking which plagues so many recordings.
"Dynamics"?.........WOW!!!!!.........absolutely the best I have ever heard from a DML!!!.......don't know if it's the thruster exciters or the more rigid panells? The PERCUSSION XX recording mentioned in one of my last posts is jaw dropping..........different!......strangely so.....very weird, yet so compellingly REAL!!!
Top end is very natural but not as fierce or prominent as the thinner EPS with standard exciters. Only burn in time will tell if this area changes or not as it could be the exciters or, once again, just the fact that a thicker panel is being used?
Detail?.............it's all there........trust me.
Mid-bass?.........lots of tonal colours and contrasts........truly outstanding, massive dynamics as already mentioned.
Low bass?........ Jury still out on this one.........panels are free standing and not mounted as yet.
Rob.
However, never once was there any question as to what was in the left channel, centre or right channel.Are you using three panels in a two main + one center set-up or are you referring to the recording of the sound?
The exciters and this thread should probably come with a warning for addictive behaviour. It probably should also state that while the initial exciters are deceivingly cheap, it somehow starts adding up after a couple of experiment...
Sounding worse??? still a but muffled? Do you think it is the thicker panel?Both panels I'm listening to are the 1" (measured thickness is 7/8") actually. The smaller 1" thick, 2 ft. x 2 ft. panels sounded veiled and distant when I first posted initially on this thread. However now after a week the small panels, compared to the new larger panels, are not muffled and are crisp and crystal clear. The conclusion. It seems to be Serge's PVA/water panel treatment... once its cured... the sound of the panel is SIGNIFICANTLY improved. I'm sure the exciters being more broken in is part of the improvement as well.
So if I'm understanding this right, the thicker but larger XPS panels still sounds a bit "muted" and that the re-skinning improves the clarity but doesn't take it all the way on the particular panel you are using.
Thank you all for sharing your progress and experiences.
I borrowed a mic to do some measurements as welland once I figure out how to use it correctly I will post some plots soon.
Do you have a line chart with more detail and not so much smoothing on? I'm just learning how to measure so I'm probably the last one to ask, but I noticed on my measurements that the boards are very sensitive to where they are held, suspension points, etc. Kind of like someone said before, you can do some equalization directly on the board.
I got the smoothest LF response if I suspended the panel, which I did by holding it by hand on the top middle. I almost got just as good if I put it on cedar rings with some moongel sandwich in between (what drummers use to dampen resonances). This removed huge swings in the plot between 20 to 80hz and also extended the top end. Do you see this as well?
Interesting that you have a peak at the 16kplus frequency, as well as the long falloff on the 25. Perhaps that will make it easier to integrate naturally with a sub??
ON_newbie
The roll off does look a bit odd ,I would expect a thinner 5mm panel to look like that,are you sure you haven't left an xo setting on ,or a capacitor left in place on the exciter? It's been done before :oops:
In my gallery there is a pic of a bog standard 2x4 panel 25mm thick I would expect a response like this ,also there is a smaller 5mm panel with a similar response to yours,I would expect more from your panel.?
Steve
I have had family visiting for the last week so I haven't had a chance to experiment too much - only sneaked in a little bit at lower volume late at nights :-)
Still on my birch boards, but I have an uncut 4 x 8 XPS board standing and waiting for me to be re-skinned and cut down to more workeable size (maybe 6 x 2'). The biggest problem for me with these these boards is the pink/purple color - these would never be allowed up from the basement even if I made them smaller. This is also why I'm still trying to get the "wood" to work.
The HF is still not there, but I still need to sand them down and taper all the sides which improved a lot of my smaller boards, plus re-glue the exciters to see how much more HF this will result in. What do you think about using the same skin-method you guys are using on the EPS/XPS boards?
There has been a lot of discussion on different material (birch, spruce,...) if you search the thread. If you do try wood, make sure the material is rigid, which may mean thicker (or supported by a frame which I haven't tried yet). The thinner 1/8 wood panels I mentioned a few posts ago flex and bend too much creating dips and spikes in the frequencies resulting in a slow and muddy sound.
I tried a new amp with a built in cross-over for fun. I set a high-pass to 3k to better evaluate the HF. That was very interesting since I couldn't really detect any vibration or movement from the board or the exciter it-self. Try it if you haven't already. So does this mean that all the HF is coming from the skin? If so this means that the HF could be done with a very thin and hard material since it will not be moving much at all. The other thing is if the vibration from the LF "ruining" the HF? Same concept as normal box speakers sounds better when dampened from vibration. You mentioned before a thre panel solution, and but what about a two panel solution where the signal is split at 3400. Just thinking out loud here, so let me know if I'm too much off.
I also want to try out the "wedgie" concept with a very narrow panel phasing forward combined with a much larger panel going towards the backside at 120 degrees or the linkwitz LX521/Nao Note style panel. Again partly for visual purposes but I'm also very curious how it would sound
I'm also waiting with excitment to hear if the curing of your panels improved the sound even further.
ON_newbie
The self noise you seem to be describing is not the panel sound we have been trying to eradicate with pva,but the large panel drum effect ,which is easy to hear if you just tap your knuckle on the panel,adding another coat of pva is not really going to help hear, as you will probably need something more drastic to sort this out.
This I have found only shows itself badly on certain tracks that excite the resonance such as a loud drumming sound ,which can set off the sound.
Also If you have an 8 ft panel lets say,there is no way that that panel is going to stop vibrating the instant you stop the music,the sound has to continue on its path through the panel like ripples on a pond ,the smaller panels will stop almost instantly to my ears anyway,on the large panels the combination of the two in the low end can make them sound a little sluggish at times ,at the moment it is probably an evil you will have to live with,smaller multiple panels per channel could solve the problem though ?
Steve
If you do, let us know how they compare. I'm happy with the fun with the panels since they sound so good. I have actually never heard OB speaker but really want to - How do your OB speakers compare with the panels and which one do you prefer?
Rock...the birch boards actually sounds great with rock. Just need a little bit sub boost on the bottom plus you need to get the panels on spikes or suspend them in the air.
If you don't mind me asking, what do you use to eq?
Yes - meant like a L shape.
OB _newbie
Once you have removed the top layer of eps ,the under surface is more spong like and absorbs the watery pva or hopefully the watery dye,if you are artistic or have a friend who is ,you could paint a lovely masterpiece? :thumb:
Is the sound coming from the centre of the panel or the centre of the exciter?if you place a 2 to 3 mm piece of bluetac in the centre of the exciter ring does this dampen the noise?
Extra coatings of any type will not do much if anything to the panel boom ,but will definitely worsen the sound of the panel ,you must remember that the more you add to the panel the more you alter the pure sound.
Steve
Yeah! Can't wait to hear your impressions of birch vs. XPS. I walk pass the birch ply every time I'm at Home Depot and slide a few out looking for flat ones but just have not been able to pull the trigger. I have the standard VHB on the small panels and did glue them for the larger 2x4 panels... think its called Elmer's Advanced ProBond or something close to that. Sedge uses the waterproof EVA and would have got that but Walmart was out of stock when I made one of my late night runs over the holiday break.
To dry the panels I've been using a hair drier... makes for some quick panel work.
Hey, what did you cut up your XPS panel with?
Forgot to mention that the panels I have only is 1/2 in which might be the reason for the LF performance
Odal, what panel material/size are you using with your DAEX32EP-4s btw???
If you were to make an MTM type DML with a dipole tweeter between two small panels, what size panels would you recommend? I intend to place them above a pair of side by side 22" HFrame woofer enclosures (approx 20-200Hz) on each channel. Essentially laid out like:
MTM
W W
XPS and EPS are available locally. Not sure what thickness or type to try first. Tectonic uses approximately a 6000Hz xo to tweeter IIRC. My hope is that there is. Material that would perform well between 200-6000Hz. My exciters are the buyouts from PE. I have 8 total. Your thoughts would be appreciated. Thanks in advance.
If you were to make an MTM type DML with a dipole tweeter between two small panels, what size panels would you recommend? I intend to place them above a pair of side by side 22" HFrame woofer enclosures (approx 20-200hz) on each channel. Essentially laid out like:Note that there are different kind of XPS / EPS panels available depending on where you are located. Some are good - others not so much. The good news is that they are fairly cheap to try out, and if you don't use too strong of glue it is pretty easy to remove the exciters and try over. I would start with 2 x 4ft to see how you like it. OB_Newbie seems to like smaller panels, but others have reported that they like slightly taller (or slighly wider), but if you are going to cross them that high you probably don't need too big of a panel. However, I would also recommend to experiment crossing your HFrame woofers much lower. The bass on the right type of panels can sound pretty amazing. I'm crossing my birch panels around 70 to 100, but I may reduce it even further. There are some that have panels that don't need a sub at all as well...
MTM
W W
XPS and EPS are available locally. Not sure what thickness or type to try first. Tectonic uses approximately a 6000hz xo to tweeter IIRC. My hope is that there is. Material that would perform well between 200-6000hz. My exciters are the buyouts from PE. I have 8 total. Your thoughts would be appreciated. Thanks in advance.
I currently have them on 2.5 x 5ft birch panels. One has thickness of 1/8, which doesn't sound too good, and the other has 1/4 thickness.
BTW: Here are some measurements of the XPS panels. Shows similar fall-off on the LF as the ones you posted - birch panels shows a much smoother LF, but the XPS has better and tighter high end. Mic at 3 ft (used the umik-1) - the lines shows the same panel but just with different smoothing applied. Probably can't read too much into the chart because it is measured in my unfinsihed basement with concret floor, misc stuff and other reflective things.
(http://www.audiocircle.com/image.php?id=112485)
Since you asked...here are some comparisons between 2.5 x 5 birch panels with thruster exciter (purple) and 2 x 4 XPS panels (green) (re-coated with cheap exciter). Same measurement, just different smoothing. Panels measured at the exact same location, stand and volume settings. It's pretty obvious which area each panel excels. Exciters attached with VHB tape since I didn't have any good glue at home. Birch panels sanded down to 200 and as an experiment I put some diluted pva glue about 5" diameter around the attachment point for the exciter. This and the fine sanding helped smooth out the mids, added the bump between 3-4k, and the two smaller peaks over 10k. The unsanded/treated birch panels barely moved the needle above 8k. Next step is to round and taper the edges a bit more, which I hope will help smooth out the 10k dips. It made a lot of impact on my smaller birch boards. May also re-skin the whole front. If you compare the XPS line in these charts vs the one I posted before (which only had the pva applied to the backside), you can see the difference in HF around 20k Hz.
Since I have little clue what I'm doing when measuring, and my basement is not the best measurement place, one has to be careful to not draw too detailed conclusions from it.
OB_Newbie - play around with dampening on your panels either by tape, Sedge pva/shellac method, cedar rings, moongel or whatever you have at home, where you lean/attach suspension points. It makes a huge difference regardless if you suspend the panels or have them standing. It will help smooth out the response especially in the LF but also in some other regions. You may be able to eliminate or move the dips/peak around 62.5Hz.
(http://www.audiocircle.com/image.php?id=112561)
(http://www.audiocircle.com/image.php?id=112562)
How small?
The one thing that makes this so rewarding is that it is so easy to experiment and then immediately knowing the result.
Oral3
I only used one exciter per panel and they could get too hot to touch ,are you still using four exciters ,if so what positions?
Steve
The number of exciters seems to make a difference in the HF response. With one exciter my 2'x4' gatorfoam panel goes up to 15Khz with 2 exciters the HF rolls off at 12Khz and with 3 or more it is lower still around 11 Khz. I presume the multiple exciters must be canceling out the high frequencies. I wonder what role spacing between exciters plays.
(I tried different spacing and it did not seem to make any difference)
After reading some of the earlier discussion about dipole vs. bipole, I thought I'd try something very different - exciters on both faces of the panel. Complete Fail! The sound was just awful. The exciters must be canceling out.
Well it looks like people decided to breeze over your testing and findings. I am happy to read some logical testing, and your results are exactly what ELAC states; which is the dB coupling when using multiple exciters is less in the HF range than the LF. Basically each additional exciter is adding more LF than HF, which ultimately equates to increasingly lower HF response.
Keep us posted on the Ultra exciters. Curious to see how they work out.
Calling them Z-panels in honor of Zygadr.
I will probably go smaller panels too make them more "acceptable" in the room - the 5 x 2.5 feels a bit large in the room. Check out this thesis for some good theoretical background (Not really journal level research material but it is for sure a much easier read than many of the other more mathematical papers): http://publications.lib.chalmers.se/records/fulltext/154618.pdf
Some comments from this:
Fig 5.5 explains that the dip and peak we see on the LF, which per this is due to the boundary conditions - how the panel is held/clamped, etc. Looks like we need to figure out how to hold it with "fully roller clamps"
Fig 4.19 shows why the panels is so much easier to integrate in a normal room than a conventional speaker - perhaps one of the reasons we like it so much.
Sorry to get you too excited :-), I was mainly reading the theory and the analytical modelling. A master thesis is normally a good summary of the theory but results of studies should be taken with a grain of salt.
The roller clamp is referring to a theoretical boundary condition used in evaluating forces and vibration in beams, plates, structures, etc. Not really sure either how to (if even possible) to implement it in practice, but here is at least a visual: https://ecourses.ou.edu/cgi-bin/ebook.cgi?doc=&topic=st&chap_sec=05.1&page=theory
(there are also roller clamps used for pipes, hoses in the medical field, etc. but I believe that is a different thing)
But the effect of clamping of the edges is real. That is how I equalize (=smooth) the LF and mid on my panels. It reduces the excessive vibrations and tightens up the bass and mid.
If you have some spring clamps at home, try put some on the edges, and measure it with and without to see the difference. If you place them right it will to some degree smooth out the peaks and dips from room and panel. It doesn't remove the issue completely but makes it better. Try for example to put one at each side of the panel around the middle- for example horizontal line from the exciter. Other positions to smooth it out is to put two clamps on opposite corners (top left and bottom right, or perhaps all four corners). Another is the top (and/or bottom) edge vertical line from the exciter.Make sure to clamp it right on the edge. Not sure if this will work with the XPS/EPS panels since it may crush them, but for the wood panels it's great. The clamping especially helped when suspending the panels in the air.
OB_Newbie - if you get a lot of vibraiton on the thinner birch board as I did, (but the boards I used were larger) you may need to add some support to make them sing. So if you're not happy with the bass, try for example to attach a thin and short wood stick on one side only of the exciter. I used one of the free paint wood stirring sticks, and this really tightened up the bass. I haven't tried it yet on the 1/4 since they sound good anyway but for the 1/8 birch or 1/2 XPS it definitely helped.
Very sorry to hear about the passing of Zygadr... my condolences to his friends and family.
So I am still considering materials for my midbass panels (200hz-2000hz or so) and have come across this:
http://www.sterlingpromotions.ca/GatorLite-Board.html
Has anyone tried the GatorLite?? It seems like an interesting product, but recall regular Gatorboard was not popular long term. I am having trouble on committing to a sheet of something to use. Funds are tight, so cannot afford to play around as much as I would like. Going to run to Home Depot this week to grab some paint for a job, and was going to take a peek at what they had on hand.
Hey Odal3,
Thanks for the kind words......i abondoned the stand because as my wife correctly pointed out it does make our living room look like a basketball court without the net!
Squibby.
Squibby,
On the contrary, I was excited to see the measurements. Half of my measurements include small feet running around or an occasional dropped toy on floor in the room over where I have my "audio lab". Didn't mean to come accross as negative - just to give a helping hand so we can continue this together. Everytime I'm reading this forum I always learning something new and that's why I'm keep coming back. Please post more when you get around to it!!
OB_Newbie,
So officially only a 2 star rating for the Ultras (assume that was you) :-). Since the trusters are out of stock I'm thinking of getting 2. You may have alreday mentioned this, but I forget, do you think they will work on wood as well? Is it a higher frequency output or what is it that makes them sound better?
Haven't been to the PE site in a while. Is the DAEX30HESF-4 something else to consider? I had not seen that one before. Don't really understand specs for these exciter other than the W output.
Have anyone made a some experimenting to see how low the frequency goes on different panel sizes. I want to try some smaller panels for looks and I can fill in the low-end with subs.
Hey Odal & OB,
no need to apologise at all.....i appreciate the education especially on topics i dont have much of a clue about such as audio fidelity and frequency measurements.
I'm going to order some of those ultras and perhaps a thruster or 2 to do a comparison and try them out on some xps....i need to know the difference between what you guys are hearing and what i'm content to listen to with my wooden panel!
I may even coat the xps with 1mm wood veneer....who knows....i have my reservations about not using wood and losing that richness of tone (plus the aesthetics are not too shabby and certainly beat looking at foam!)
thanks for the kind words and dont worry about hurting my feelings with constructive criticism...the knowledge i gain far outweighs any negative thoughts i could have (plus i'm a big boy....i can handle it.....sniff).
all the best,
Squibby.
If there was only more time in the day...have had 2 ultra exciters sitting on my desk to be installed for a while now - haven't even had a chance for a listening test. Maybe this weekend.
Hope you all are doing great with your panels projects.
Hello all,
I have spent the last 4 days reading through this entire thread. Definitely a kick in the stomach. I have been following this because I wanted something different and fresh. I want to use these to implement my 7.1 surround sound for my dedicated home theater. I notice you all mention listening to music but rarely do I see a mention of movies or the like. Would these be feasible for this purpose or should I just stick with conventional? (REALLLY like the panel idea!)
I noticed about 15-20 pages ago -ish that yall started using the term XPS. I seem to recall that waaayyyy earlier it was deemed XPS was expanded and EPS was extruded? Maybe I got it backwards. Which to use? For three HT I could use the ply as well not really tied down to one material, just want one that will sound ludicrous in the movie room.
I gather if I'm reading correct that the "Ultra" is the "preferred" exciter to use 1 per panel? I was looking at PE today and didn't see the "Ultra" descriptor. May have missed it, anybody got a part number?
The plan will be to power with a HT receiver and will probably end up augmenting with a horn sub, any guidance, criticism will be appreciated the panels would end up approximately 2ft x4ft for each of the 7 channels. Center channel mounted horizontally. Mounted to the wall to minimize the amount of real estate taken. Thanks in advance for putting so much time and effort into this thread/project!
EDIT: Found the exciters...just missed 'em.
Connections then,
Would you definitely recommend solder or just reeeeaaaallllllyyyyyyy careful application of disconnects?
I had a question about the amount of exciters per panel. I read here towards the end that others were satisfied with one per panel. Also that there was a loss of HF when using multiples. Will one per panel end up being enough? I am concerned that it won't play loud enough.With the more powerful 40W exciters you probably only need one - especially if you use XPS boards. I have been running 4 low power ones (monacor placement 1-4 as well as "tuned-by-ear") on thicker birch boards. I was happy with the results but created some minor spikes in the frequency plots, but not too bad.
I still have to figure out materials to suspend but I am considering 3mm rubber cord used in jewelry making. My thinking is minimal size but still won't transfer what little vibration they get to anything else.
Alright - prepared another board and finally had a chance to listen to the Ultras and compare them to the Thrusters. My initial impression was better clarity at the expense of the bass. The boards were really large 2.5' x 5' at a 1/4 " thickness so it might have been too heavy for the Ultras (final boards will be smaller), but then on the other hand I have two subs in the room so the boards doesn't need to go down that low. More impressions to come later this week.
Can I get a Hellelujah!? I have seen the light my brethren and it is GOOD!
Seriously though. I "finished" up one of my panels this morning. I did a quick wire up job and set it to rest on top of my sub. I hooked it up to the right main just so I could hear the difference between the old HTiB speakers and I was amazed!
The panel itself looks like crap but it sounds extremely nice. I normally had to turn the avr to 30ish to get the sound out. With this thing I had it set on 13. I played a few movies just to see what I could hear.
1. Fast 6- When the cars are coming off of the elevator I could hear the individual pops of the exhaust. Like the car was driving in from stage right.
2. Act of Valor- When the River Rat comes in and unloads with the Dylan........WOOOOOOOWWWW! Before it was just a low rumble, now I can hear the gun spinning, the brass hitting the deck and when they open up with the other gun I swear I can hear the bolt cycling.
In short, the clarity is astounding for movies, and this is just propped up against the wall with nothing insulating front the wall or sub. I was worried that they would not go low enough but the small non powered sub was easily enough to meet it.
The wife walked in as I was testing and said the pnel sounded really good. Clearer than what we had and she was happy with what we had.
The panel is 22x35.5 coated 1 time on each side it a 1:1 mixture of titebond3 and water. (I tried to color it with water soluble craft paint the Mrs. had lying around mixed in, don't do this, the paint left little chunks all over the panel which is why the panel looks like crap)
The single XPS pink panther board more than overpowers the other speakers and now I am excited to fix up the others.
Just a quick update to let yall know what I think. When I get the others done I'll post more!
:thumb:
Sounds like we have another believer joining the club!!! I had almost the exact same feeling myself when I first heard it properly mounted on a board, and actually still do evertime I turn it on.
Update on the Ultras and the knocking. It looks like both Ultras I have do not have enough space between the magnet/mounting ring and legs. Not sure if this is an assembly error for the ones I have or if it is per the actual design. One of the exciters looks like it is slighly tilted in the way it is assembled - it is "sunken -in " more where the sticky stuff is.
Anyways, as I mentiond before, if not playing them full-range or on lighter/smaller boards it will likely be OK (unless you have one "sunken-in" that makes the exciter not sitting straight in the plastic housing.) Tried to buy a thicker XPS board today, but they were out of stock.
BTW: Had a thruster dead on arrival - the wire attaching the coil to the speaker tabs was broken-off. Hope to be able to return it.
Yeah... as much as I like the Thurster's bullet proof construction (steel spider and top quality construction) and they do sound notably better the Dayton Audio DAEX25FHE-4... but dang, I have to say that the Ultra's still have my complete love and attention on XPS. They do look cheap, are fragile but they sure do sound fantastic on XPS (and other lighter materials I'm sure).
Is this really the consensus? I'm shocked the puck design's sound quality is preferred over the DAEX25SHF-4 or the DAEX30HESF-4.
I would be curious to know how the Elac driver (which JMC soundboard uses) sound in comparison... or the Visatons.
Hi all,
new guy in town.
I' m from Slovenia, currently staying in Indianapolis.
English is not my first language so please,... :lol:
I have been following this toppic for a long time and finally decided to participate in it.
Recently I bought ten of DAEX30HESF-4 exciters. My plan was to use two of them for experimenting on different panels and then on a panel with best results put four exciters on each panel.
But what I have found out...these exciters are loud!!!!
Anybody has any experience with these exciters?
Should I stay with one exciter per panel or should I go for four per panel.
I'm afraid of losing heights due to the interference between exciters.
Panels are made of CG...109cm x 65cm...golden cut.
Experimental, not final product.
(http://www.audiocircle.com/image.php?id=119424)
(http://www.audiocircle.com/image.php?id=119430)
(http://www.audiocircle.com/image.php?id=119427)
Thanks OB.
Material is CC and not CG as I've written in previous post...sorry.
The sound?...
Oh my,....vocals are to die for, acoustic instruments amazing !!!
Only one condition; it has to be good recording.
Heights; can tell, doesn't go up to 20.000kHz, but it's not really noticeable in listening.
Bass: goes deep enough to give good foundation for overall listening experience.
Even if it sounds much better allready now than most conventional speakers, there is gonna be a lot of elaborating when I'll be back home.
Welcome aboard! Great to see more people from Indianapolis posting here.
Dang, my oldest son and I were in northern Indy (Westfield) Friday-Sunday for soccer... should have meet up you fellas for an adult beverage and some good food or something.
Saw that the Ultra's are out of stock. If anyone wants to try a pair I would be happy to ship a pair out for the sale price and actual shipping (bought a load of them while on sale). Should be able to ship in a padded envelop pretty cheaply I would guess.
Dang, my oldest son and I were in northern Indy (Westfield) Friday-Sunday for soccer... should have meet up you fellas for an adult beverage and some good food or something.Hope there will be more opportunities
Update: Finished the front 3. 22x35.5 in. Painted up and sounds b-e-a-utiful!
It is my own design it is the first prototype, Now I am working with a new one with two spiders to reduce the amount of rocking motion. See pic.
(http://www.audiocircle.com/image.php?id=120258)
Your comment bolsters my feeling that DML is very much an art form. Surely it is one of the cheapest DIY projects available for the stereo nut :) And believe me, I know cheap!
Sorry about that, should bee OK now.
Thanks for sharing the picture. Looks nice. So do you have one exciter on each of the four floating panels? Are all full range?
Neat. Thanks for claifying.
There has been some discussion on multiple smaller panels like this but I haven't heard of anyone tried it before (Or I forgot from the long thread). Often the recommendation is large panels are good for bass, but your set up proves small ones works as well. Did you ever compare the souND from your smaller panels with one larger? I'm curious to hear what your impression is. Not as wide and large would be easier to place in the living room plus it looks better imo when the panels are not too large (like the big ones I have currently)
With all due respect, I really think putting a hole in the panel convolutes the basic NXT technology.
"Any" plate connected to the exciter will function as a low pass filter to some degree. Now that we're seeing exciters that handle more power, I see nothing wrong with adding a little high frequency EQ. Sooner or later materials used by professionals will trickle down to DIY.
I haven't been on here for a while, but I thought I'd share a photo of something I put together a few years ago. It uses low power exciters, mainly because there was nothing higher wattage available at the time.
I used corrugated plastic panels floating in four separate frames and EQ'd the high end. Bass was very substantial to 50 hz, and sounded pretty nice on a wide variety of music.
(http://www.audiocircle.com/image.php?id=122223)
Now that's what I'm talking about! Good looking panels... what are the dimensions??
This is where I plead "guilty"!
The panels are 12x12 inches, the frames are made to allow a 13 inch opening per panel. I know.......I know, no golden ratio! Guilty on the first count. Also the exciters are mounted dead center, guilty on the second count.
There was nothing all that technical or arbitrary about panel shape or exciter placement. I simply ran pink noise into test panels of various shapes and sizes and tried moving the exciter around until the spectrum analyser showed the flattest response. The center was also the spot that sounded best to my ear.
How many loudspeaker "designers" have achieved their goals through empirical means? Plenty, I'm sure!
The exciters are freely mounted, no individual or common spines were used.
If you check some of the recently linked technical papers you will find the theory that confirms some of your findings regarding weight and suspension. Perhaps can give you further clues to help optimize your design. Will take a peak this weekend if I can find the particular paper I'm thinking of.
I think you can get both low and high frequency with the right design. Efficiency is another matter...
I really like the tall and thin and surprised by the bass response! Imagine they are efficient as well.
One of the first panelsi built were square and they sounded very nice. According to one of the papers very close to square is optimal for the most efficient generation of nodes so given that and what I heard with my ears a square panel is not terribly off the mark it appears.
In regards to exciter placement Monacor placement is probably best however with my array I do plan on moving excites to different positions on the panel to randomize the freq. response somewhat for what I hope is an overall smoother summed response.
Again, thanks for the pics and explanation!
Hey Capin'
Yeah, I'm not a proponent of multi exciter panels. 1 exciter per panel is why I want to create a thin tall panel for high output and ability to EQ with the extra available power handling. I mention Monacor as I am planning to distribute the exciters in different positions on each panel to randomize the FR so given the 4 panels the overall FR (I hope) is smoother.
That is the thought anyway, we shall see if the theory proves out.
Funny your wife doesn't like the thin and tall look... I think that's a really nice look and should provide a focused array at most listening distances I would think. Will probably have mine pulled a bit off the ground so the center of the panel is about at the listening height to maximize the distance that you can listen to them in the focused (line) array... really like listening to them as a line array... always imagined that was one of the contributing factors of why the guys like the bigger panels(!?!).
Yeah, I'm in the same position as you really. The size of my room isn't bad but just no good spot to set up a nice audio system so at the beginning I was interested in these as they are light and could be picked up and moved to a closet or some other spot. Funny, I'm shooting for a MMG or Eagle look as well. We should be able to do this without to many problems I would think!? I'm going to use black ink in the PVA:water treatment, paint the frames black and use grill cloth to cover everything except the sides. Still deciding on whether to use natural wood sides or also stain them black. I like wood but the all black look pretty killa.
The Eagle's are also very nice looking.
I think where I made my mistake was choosing white for a color, it stands out like a sore thumb. Black would have been the way to go, more dramatic yet understated.
I get so wrapped up in the R&D of speaker building that all of my prototypes wind up looking like ,well............"prototypes".
For me the best thing about quality DIY is that the guy down the street isn't going to be able to walk into a big box store and buy the same thing you have.
Same... I'm more interested in the next build instead of finishing the existing design. But that is where the fun is... fun to build and try different things. :D
Same... I'm more interested in the next build instead of finishing the existing design. But that is where the fun is... fun to build and try different things. :D
I found this photo of the Goebel crossover. Apparently it's not just for crossing over their bending wave transducer to their woofers. They mention that it's also for linearization of the bending wave driver.
To me that seems to infer equalization.
I can't help but wonder what Oliver Goebel's panel would do connected directly to a flat amplifier. They claim they're bending wave device goes up to 29,500 hz. "Does it" or does it need some help?
Admittedly the fluted corrugated plastic I used is lossy, but high frequency EQ seems to work.
Jack
(http://www.audiocircle.com/image.php?id=122427)
Would not surprise me in the least bit if some modification of the freq. response was done. We do it with traditional dynamic speakers so why not with a DML panel right? :D
I have been reading through this thread and there are a number of different materials, sizes, dimensions, etc. described. I ordered a pair of DAEX32U-4 to experiment with. The drivers include pre-attached 3M VHB adhesive. I suspect that this adhesive is intended for permanent mounting.
How are people mounting the drivers when experimenting?
I've been making my way through the thread. Lots of info here. I'm still waiting for my exciters since they are on back order. I will go out and buy some different double sided tapes to play with while I'm waiting. See which ones are sticky enough but allow me to still remove the exiter. I'm hoping duct tape will work... just because its duct tape.
I received my exciters (DAEX32U-4) on Friday. I placed one on a 24x24x1 piece of untreated XPS from Home Depot. I used the Monacor recommendation for placement of the exciter. Currently, I'm underwhelmed. Its cool that the thing makes noise, but it is far from sounding good. I downloaded Room EQ Wizard (REW) and plan on taking measurements so I can compare it to a full-range speaker I have.
I'm looking at this as the first step in a journey. Next step is to make another XPS panel that has a "better" geometry to see if I can hear the difference and see if there is a difference in REW.
...gives the panel a sound that I can only describe as frightening.:thumb:
OB_newbie
I wouldn't want you to think I'm tight,and that I only use the old washing up pads because when the other half throws them in the bin they are FREE :banana piano:
The very large panels do suffer from panel resonance in the lower end ,a CHEAP :banana piano: trick I tried some years ago was to glue a piece of wood down the centre of the lower half of the panel probably no more than 18 inches long ,I had the idea of using this as a mounting point clamped to the floor.
If I remember right :scratch: it didn't effect the sound of the panel too badly as the rest of the panel was free floating,I didn't follow this up as I wasn't that interested in a 8x3ft panel in my small room ,small panels don't seem to suffer from this problem.
It's just a thought but it might do the job of damping the resonance on very large panels without interfering with the overall sound too much ?
Steve
OB_newbie
Have to say that all the white papers I have read so far ,although interesting have not mentioned much about how to achieve the best sound quality,it's usually more about exciting as many nodes as possible to produce as much sound (noise) as possible !
Clamping the panel in a frame (nxt) sort of amplifies the nodes ,adding weights to the panel changes the shape of the node pattern ,adding a roll surround dampens the panel and lowers reflections (nodes).
All of these things have a knock on effect a sort of catch 22 situation,large panels have their problems ,small panels have different problems ,different size panels give different room responses ,moving the panel to another room can totally change the sound.I could go on ,but will leave it there for now as it will only give me a headache.
So far ,for me anyway,the best sounding panel is the free floating poly type panel,with a little help from my TLS to fill in any dips in the room response below 300hz,although I do have the equipment to EQ the panels I must say I have not found it necessary.
The slight mods I do use on the panels,don't have bad knock on effects,if they did I wouldn't use them.
Using multiple panels per channel could help fill in the dips ,especially if you had different exciter positions on the panels, to spread the nodes on the panel and in the room,cancelling the cancellations (which is basically what I am doing with the TLSs).
I've got to the stage now where I just don't want to do any more testing of panels,all I want to do is set up my final system and listen to music,as I'm typing this I'm thinking of other ideas :duh:
Steve
I also find that the bigger panels move more and requires some more work to not color the sound. Suspending them has worked the best for me. I put two nails in the side abut 5cm from the top so nothing touches the front or back side. I attach a wire to the nails so the panel can move freely in all directions. This is building on the idea of the paper we discussed a while ago with all the theoretical models.
If standing on the floor is a must, the solution I use is putting two nails with rounded heads on the bottom to allow some movement. The round nail heads stands on cedar blocks with moongel underneath.
The difference you see in the LF is huge using these methods (in particular the suspended) and it really takes out some of the big peaks and dips. If I just have the panels standing on the floor with nothing underneath the frequency response below 100hz has two large peaks and two lare dips.
...my new thin and tall panels that will debut this weekend! 1.5 x 5 ft with the first one stained up to match my living room coffee table. Curious to see how the stain affected the sound. Hopefully not too bad. Would like the panel to go down to 100 so will see how it works.
I always wanted to hear the metrome - that looks really good!
But, before moving on you got to treat the panels. When I played the panels raw, I didn't like them either - it sounded like the sound came through a pillow and not very clear. Get some glue on them, and you will hopefully like them better.
Exactly my thoughts.
I noticed Tectonic uses a tweeter with their DML's, so even the pro's have an issue with high frequencies.
I've really given some thought to make an updated version of my 4 panel DML using high power exciters. Last night I did a quick Photoshop on my previous prototype and took out the feet. My Wife still "hates" the look of it. I guess I'm beating a dead horse.
Jack
I apologize to the community, but I think the theme NXT not so topical
We studied and tested many NXT speakers (include Tectonic) and finally we came to the following solution: The best of the best sound quality solution is vertical line array from 2-2.5" Balanced Mode Radiator Drivers (BMR) with sub-bass section in each L & R channel.
Like this well known K-Array products (with usual mini drivers) http://www.k-array.com/en/portable-systems.html
As sub-bass we successfully use subwoofers ( 20-200Hz) with SERVO control
8 or 18 BMR drivers section (4ohm resulted) work from 150Hz .
OB_newbie
I think my used foam pads might smell better too :oops: :lol:
Your old athletic socks could also be affecting the the air :oops: and detail in your panels :thumb:
But seriously,resting the panel on the floor or even foam will have an effect on the sound ,just touching the panel with your fingers is enough to fill in those dip or even move them around ,if you stand in front of the panel and clasp the edges while playing pink noise you can readily hear the sound close in to the middle area ,using a light and soft foam suspend from a single point allows the panel to shake freely ,is robust and allows you to clamp the panel on to most things with a washing line peg,heck! you could even use a washing line :scratch:
Time to go to bed.
Steve
I really like my metronomes. I have brought them to a couple of audio meets where people who didn't like the Fostex in other enclosures thought they sounded really nice.
Don't worry, I plan on trying lots of things and measuring each change. This way I can have documentation and empirical evidence of what changed. I know measurements don't really tell you how something sounds, but at least I will know what changed rather than guessing. Also, I think others will be interested as well.
I have another panel that I have treated with shellac that is drying. I know lots of people use the glue mixture, but I was thinking that shellac is a very hard finish so it should work well. After thinking I thought of something new I read earlier in this thread that people have used shellac and like it, so I guess no discoveries.
QUESTION: Should I treat both sides? The answer is in this thread somewhere but I'm feeling lazy.
So, here are the experiments I plan on running:
- Untreated 24x24x1 XPS
- Shellac'd 24x24x1 XPS
- Untreated 24x22.8x1 XPS (this is the ratio recommend in the white paper reference earlier in the thread)
- Shellac'd 24x22.8x1 XPS
- Untreated 24x14.8x1 XPS (golden ratio)
- Shellac'd 24x14.8x1 XPS
Then, if I'm feeling up to it, I may do the same thing with plywood.
I need to refresh my memory tonight but I believe they went away and smoothed the whole spectrum. Will check if I have some old measurement files - can't take any new ones because the exciters are off to be mounted up on my new thin and tall panels that will debut this weekend! 1.5 x 5 ft with the first one stained up to match my living room coffee table. Curious to see how the stain affected the sound. Hopefully not too bad. Would like the panel to go down to 100 so will see how it works.
It's a nightmare.but that is also what makes it so addictive - the holy grail always feels to be around the corner.
One of my mods sorted out the hf problems above 10k on my 5mm panels ,near fieldCan you summarize the mods that you do again in addition to the PVA/glue mix? Do you do different ones for different materials?
also the peek at 80hz drops away when the panel is suspended(it was standing on the floor)
These DML panels are very open, spacious and free of any box resonances... akin to an open baffle speaker.
Personally, I think they will integrate best with an open baffle speaker but Sedge has good success with a transmission line. Also, commercially Tectonic used a Heil ATM tweeter 6KHz and above (fast rise time/transient response) and Gobel uses a high-tech DML really full-range with conventional boxed woofers to handle bass duties below 170Hz. So many different combinations have been produced so no technical limits to what can be done.
I think placement in the room is more important than integrating with other types of speakers. I find that they need more room like an OB for best performance (so why not go ahead a build a small U frame or SLOB under the panels??? :green: :thumb: )
I have some exciters from PE I ordered reading the thread over there...can anyone recommend a size panel for mid range?..I'm not worried about bass...looking for live ambiance..thanks for any reply
I too have been away for a few days holiday ,just got back,there's a lot of questions,not sure where to start.
Shellac.
It might still be going through it's ageing process? Can't wait a year though,as it is at the moment it adds weight and dampens the panel ,a bit like doping a paper cone,for me not so good as it makes the sound smoother but softer with loss of detail.
As for the pva treatment ,I don't actually regard this as damping if anything it does the opposite ,I first noticed this when used on cc ,the pva helped spread the sound across the panel and helped the panel sound less cardboardy .
It did the same sort of job to the bog standard eps ,but now with the horrible sounding skin removed and replaced with pva ,it's a win win situation.
My TLS have doped cones ,they sound great with jazz or classical music ,but put on some heavy rock and they start to sound like my nan knitted them from old pair's of socks!
Steve
For a cheap and convenient "starter" system, it hard to beat the Dayton Audio iMM-6 Calibrated Measurement Microphone for iPhone iPad Tablet and Android along with the Audio Tools app. I also have a 1/12 octave RTA ($4.99) which is pretty reasonable resolution all things considered. You will also need one of the many (free) freq. generators. I use pink noise to get a general idea of the response.
The DA mic is calibrated and you use AT to import the cal file. You can't compensate for the room with this simple setup. For most accurate "measurements" you should make measurements outside.
But this is just handy and can be wiped out for quick tests and certainly gets you into the ballpark as to what is going on with the panels from a freq. response perspective.
Sounds like you have been busy!! Very interested to hear about panel materials, suspension and sizes used and some of the insights you gleaned. Did you have a favorite or a couple that stood out?
I'd like to point out that I don't spend all my time in the kitchen washing clothes and cleaning dishes................................. .....i don't have time,not with all the house work I have to do :bounce: :whip:
Its been longer than I expected but I finally got around to measuring two 24x24x1 XPS panels. One with shellac and one without. The measurements don't really look that different, but the shellac version does sound less "fuzzy" (as someone else has described it). I was going to play with the dimensions next but since people insist PVA is better than shellac, I think I will try that first.
(http://www.audiocircle.com/image.php?id=125110)
Shellac is one of the hardest finishes (don't remember where I read that). My glue is drying now so I can compare it to shellac finish soon.
By the way, do people sand AFTER the glue dries? I sanded the skin off before applying the glue, but I was wondering if people sand again.
Shellac is one of the hardest finishes (don't remember where I read that). My glue is drying now so I can compare it to shellac finish soon.
By the way, do people sand AFTER the glue dries? I sanded the skin off before applying the glue, but I was wondering if people sand again.
2) panel mounting. No mounting; minimal suspension/damping. Mine sit on soft fleece material while the top of the panel leans against rubber bands or soft cloth if the exciter needs the extra damping.
3) exciter mounting (both connection to panel and (if any) auxiliary mounting). VHB that comes with the exciter or Elmer's Probond Advanced once the exciter is removed and needs to be remounted to a panel.
Got pics ?
Hi everyone,
Decided to join you guys here. Been reading a while and experimenting a bit on DML panels on suggestions found here. So thank you guys!
I currently have 4mm thick (in reality 3,5mm) 600 mm x 1200 mm birch plywood panels in testing. I have to say that I really like the sound that you can get from panels!
My actual speakers open baffles and they sound a bit muffled compared to panels and the omnidirectionality of panels is great! The OB bass is a lot better though as the panels don't run low enough well enough. I don't have any measurement available but they seem full range to me. Some times the panels sound amazing on bass though and sometimes not so much. Haven't yet identified fully why or if it is due some specific frequencies.
I also have xps panels underwork. They sounded more detailed to me than the birch to begin with but very bright. The size is roughly 20mm x 600 mm x 1100 mm. I sanded them and rounded the corners and that already helped on the brightness and the sound. I will try the treatment with glue next. To me the sanding seemed to loose some of the stiffness due to missing the skin from the panel. I think the glue-mix would help on that actually. Also was thinking that some sort of lacquer might also do the trick.
I am planning on building some frame where I can insert different panels and use removable cloth covers to hide the monstrosity inside. Should be fun.
The exciters I have are the DAEX32EP4.
Here is pic of a birch test panel. I used aluminium profile and few pieces of window insulation rubber to suspend the panel. On the back there is also my open baffle.
(http://www.audiocircle.com/image.php?id=131257)
I think I have to get some measuring device and DSP at some point to play more. I think 2 way with OB bass or sub + panel is the way to go unless some figures good way to make panel sub. Would UMIK, REW and MiniDSP be a good idea?
-Ossi
Here are picks of my 24" x 30" 1 inch thick XPS panels (bare) with mid-century inspired ( :lol:) stands...
Thanks ! ........... I gotta try it ........... Parts Express here I come:thumb:
I like the stands. Nice job! Now you just have to paint them pink and call it a day.
Did some experimenting last night with smaller panels and for ease of testing I glued the back of the exciter to a wood spine and used VHB between panel and exciter. Realized that in this setup the spine also makes sound and that having the back fixed creates a little bit of vibration problem for <130hz since the forced pushed back has nowhere to go than forward
Did some experimenting last night with smaller panels and for ease of testing I glued the back of the exciter to a wood spine and used VHB between panel and exciter. Realized that in this setup the spine also makes sound and that having the back fixed creates a little bit of vibration problem for <130hz since the forced pushed back has nowhere to go than forward
Whaaaaaahaaaaa... :-)
Hi Guys,
I'm glad to see that everyone is still experimenting and that the interest demonstrated by all is infectious and bringing in new people and their ideas!
just wanted to let you know what I'm currently working on (especially after seeing everyones efforts so far)....
I recently purchased some xps panels of varying thicknesses and types (open cell and paper backed)....the open cell panels are by far the better sounding material, so much so that the high frequencies sound almost too sharp and are almost a little harsh on the ear....it was lacking a little warmth, something I had in abundance with the birch ply panel.
so as a result of that little experiment I decided to glue three 5mm thick xps panels together with a slight curve in them (as I did with the birch panel, mostly to create tension across the front of the panel and hence maintaining rigidity, and compression on the back). I have since tried veneering a 0.8mm thick maple veneer on the sides and front...I will most likely also do the back but after a few quick listening tests which involved holding a single exciter to the rear of the panel, it already sounds a lot better than the birch ply panel.....high frequencies are crystal clear and I even have some bass, something which was almost completely absent from the birch panel.
the panel itself is super lightweight (i'll post exact weight and measurements once its finished) and only requires one exciter as opposed to the 4 exciters I used on the birch panel. It still needs some work (sanding, shellac, etc). There are a few wrinkles in the veneer due to my vacuum press bag failing, but I hope to get rid of most of those after some sanding and some more glue on the edges that require it.
here are a few pics to whet your appetites in the meantime....
All the best,
Squibby.
(http://www.audiocircle.com/image.php?id=131431)
(http://www.audiocircle.com/image.php?id=131436)
(http://www.audiocircle.com/image.php?id=131434)
(http://www.audiocircle.com/image.php?id=131445)
(http://www.audiocircle.com/image.php?id=131447)
ossi
you mentioned the ply low end response ,this is a quick pic of my 3x2ft ply panel response at 12ft distance, it had to be quick because of the road noise at this time of day
(http://www.audiocircle.com/image.php?id=132075)
steve
Gary.m
I've loaded win 10 ,and now my computer is up the creek,so can't post pics , the panel is 3ply hard wood 3.6 but my tape measure says it is 3mm ,that's all I know.
It's two thin sheets glued either side of a thicker sheet 2mm or so .
Steve
These are resting on stands with a medium weight felt trifolded so pretty well damped on the bottom edge. Top edge resting on thick rubber bands near the top corners of the panel but it isn't very rigid so it does make very light contact with felt padded rest that the rubber bands are attached to.Hyper Thanks ..... !!!!!!!! .......
View of front and back:
(http://www.audiocircle.com/image.php?id=132243)
The slide in insert that shuts a doggy door ...........
Hey guys, I'm a newbie here, but am intrigued with these sound exciters! I have been playing around a bit with these and experimented with putting 2 exciters on the back of an acoustic guitar and the result was pretty awesome! I don't think it's audiophile grade by any means, but sounds a lot better than a lot of normal speakers. There is a natural sound and when there is acoustic guitar playing you almost think the guitar itself is playing! Here is a demo on youtube: https://youtu.be/GRJdIv_zvag
Let me know what you think, and what could improve it!
Thanks!
Hey Tom, welcome to AudioCircle.
Interesting experiment! Maybe try damping the strings, see if that cleans it up a bit.
Groovy !!!!!!! ........... That really opens up a lot of other possibilities
for the exciters. (Cringe (Lest I say resonant))
Like the guitar! - think I saw one like it somewhere else too and there is also ones with pianos that can be bought. Almost a full orchestra now!
Try losening the string so they are not super tight and perhaps dampen them with felt. You can perhaps use it with a capo so it looks nice. I wouldn't play to low bass on it with the fear it would ruin it or losen the glue over time.
You can power the lepai with a battery so there will be no cables shown. That would be a sucess on a party to be able to fake play some pretty advanced guitar solos!!!! Or even better, remove the case or get one of the small chip amps and hide it inside!
I think I will test some stuff that sign and such makers have.
There seems to be multiple types of Kapa board available. Ther had been mention that kapa is no good but any idea on the material? There is everything from paper to aluminum skins.
Also anyone active listened to dibond? How they would compare to foam?
This will take some scouting.
-Ossi
Hi osssyvan,
I went to one of my local digital print stores and introduced them to the world of sound exciters, they thought they were pretty cool! Anyway, I did have a chance to test a few materials while I was there. I tried foam board, Gatorboard (black) and a large piece of dibond, it seemed to be aluminum sandwich with a plastic core. From what I remember, the dibond sounded decent, but I believe the gator and foam board sounded better, I think the dibond was too heavy. I was using a dayton audio exciter, the one with the three legs, powered with dayton dta-1 battery powered mini t amp. It may be worth you checking it out for yourself though! Cheers!
Now, I do have to admit, I do not know how to play the guitar for real yet, my wife had bought me this guitar a while ago and I took a few lessons, but never continued to practice. Right not this is the closest I get to "playing" the guitar :(
OB_ newbie
How did you get on with stripping your exciters?
Way back on page 10 their are some pic of what to expect when they have been stripped.
Gatorboard was the panel zygadr used many years ago ,but in the end I believe he felt it was over damped by the two layers of coating,although it performed well.
He then moved on to vh eps ,very large panels again,he was very lucky with his supplier , I would of had to buy in bulk at great expense , I only managed to get a small sample,I wish I could have tried this one in the larger size ,lightness and rigidity ,no damping.
Steve
What have other folks tried for treatments on ply?
Time to go exciter shopping again. I need to get a whole bunch of exciters for some panels that is not going to play so loud so I'm wondering which of the lower priced one to get. So far I have pretty much focused on the 40W ones, but need some new ones to experiment with on tiny panels.
How are the Dayton Audio DAEX25FHE-4? or any other good low cost options?
On a different topic: These smaller bass shakers have caught my attention as a potential for sub panel - TT25-16 PUCK. Anyone tried one?
BTW: The newer one Dayton DAEX32Q ones are on sale, but are they any good? OB - did you get yours to sound good once 'broken-in'?
- Have tried PVA glue-mix per the XPS/EPS receipe. Didn't do much if I remember it correctly (no significant change on measured frequency response or noticable difference in sound).
- Properly gluing the exciter made a big improvementon my panels.
Have you tried larger panels and cross lower to get some more dynamics?
Sedge - Excited to see more on the ply panels! Still my favourite! I even had a bass ply panel behind my couch for a while to even out the room modes (only took it away since I needed the exciter for a new experiment)
Ossyvan and Sweenz27-
Re - Gatorboard. In the US, it's easy to get hold of either gatorplast or gatorfoam and I have tried both but only in small sample sizes. I liked the foam version better, and I got better result with this than the XPS. But again, not sure how it will sound full panel. A bit too pricy in large sizes.
The aluminum/brushed cupper looking sign boards are interesting. I tried a small sized sample. They take a hit on db vs wood, but - they take the frequency way way up - perhaps past my measurement range. In fact, I had to put a Low pass on it around 20Hz since it "tickled" in the ears - couldn't really hear the signal other than it felt somewhat uncomfortable. So very promising as a small tweeter panel.
Time to go exciter shopping again. I need to get a whole bunch of exciters for some panels that is not going to play so loud so I'm wondering which of the lower priced one to get. So far I have pretty much focused on the 40W ones, but need some new ones to experiment with on tiny panels.
How are the Dayton Audio DAEX25FHE-4? or any other good low cost options?
On a different topic: These smaller bass shakers have caught my attention as a potential for sub panel - TT25-16 PUCK. Anyone tried one?
BTW: The newer one Dayton DAEX32Q ones are on sale, but are they any good? OB - did you get yours to sound good once 'broken-in'?
Cool - so how do you like the pucks? If you have some time, I'd be interested to hear how they would sound on some thicker birch plywood and low pass it perhaps around 100 - 150Hz. My guess is that the plywood needs to be thicker since it will over-vibrate the board if it's too flexible/floppy.
Ossi
As for roughness and holes ,I have used panels with very rough surface but can't say that it mad much difference,my dog stamped a great big hole in one of my panels and it still played well!
On the other hand I thought I'd be clever(lazy)and use a rough sandpaper to sand my eps panel,it felt very fluffy , and soaked up a lot of glue ,but didn't go totally hard,still felt softish ,does not sound as I wanted it to.
Has anyone compared the sound of the 1inch eps and the 1inch xps ,do they sound the same ? I only ask as some of the comments of xps sound are not good,I wonder if the self noise is different,harsher in some way,the 5mm thickness xps panels I use ,after sanding and coating is quite dead sounding,but on the thicker 1inch panels this may not be the case,any feedback on this would be great.
Thanks.
Steve
Cool - so how do you like the pucks? If you have some time, I'd be interested to hear how they would sound on some thicker birch plywood and low pass it perhaps around 100 - 150Hz. My guess is that the plywood needs to be thicker since it will over-vibrate the board if it's too flexible/floppy.
If material sound signature is to be checked, does anyone know what material the small BMR units are? That could worth trying.
-ossi
I lost my first Thruster on my ply panels last nightSo what do you do when you loose them? Only asking so I can try to avoid it, and perhaps we as a group can come up with ways to mod the exciters to be more durable.
I was really digging the ply and thought that I might be going in that direction... finally!!....
but after listen to just a few song...O no....that was quick. :lol:
treated XPS sound more clean, detailed and more natural with better rhythm... more effortless.Here's my experience: clean - check, detailed - check, not as natueral as the ply imo but still very good, but that's just my ears in my room. I really want to like the XPS, especially since they play louder and are lighter, but I can't get them to my liking. I can't fully get rid of the veiled sound. Might be user-error on my part - but I tried small and large panels, different thicknesses, different glue types and layers of glue, different exciters - doesn't matter what I do - it sounds good with the exception of the veiled sound. HELP!
gez, I cannot see how a thicker, heavier ply panel could provide more detail over a thinner panel?!?I think we use the panels a bit differently. I play them full-range or around 100HZ while I think you cross them higher and can then use smaller panels. In order to get good and clean bass, it's my experience that they need to be as rigid as possible so they will not become 'floppy' - this is especially true when cranking them up while crossing them at 120hz or lower. I can play 1/8" at low volumes or cross them really high - but I agree, the bass doesn't sound good when playing louder. The 1/4 is perhaps too thick and something slightly smaller is what I found is better (after some hard work with the sander). Even on the thicker panels, it doesn't get much of the slam that you will get from a sub, but I have to say as an old electric bass player, that the bass from the panels is very clean and detailed. :thumb:
Hey Odal,
I got a pair of the AuraSound AST-2B-4 shakers a few weeks ago to try a bass panel or combine the shakers on a larger panel and integrate it with a smaller panel (of potentially higher quality material) to handle 150Hz to 20KHz.
As I spend more time listening to the flat panel + sub combo I am getting more comfortable that a 2 way panel might be possible. While the integration might be possible, I am still weary of DML bass... is it really better than what can be had by a traditional woofer in an Open Baffle U or H frame?!?!? I really doubt it, and the The Eminence Alpha-15A is about $65. But want to give it a try anyway... for fun if for nothing else!
Sorry for keep you waiting. :D
So what do you do when you loose them? Only asking so I can try to avoid it, and perhaps we as a group can come up with ways to mod the exciters to be more durable.
... finally!!.... ...O no....that was quick. :lol:
Here's my experience: clean - check, detailed - check, not as natueral as the ply imo but still very good, but that's just my ears in my room. I really want to like the XPS, especially since they play louder and are lighter, but I can't get them to my liking. I can't fully get rid of the veiled sound. Might be user-error on my part - but I tried small and large panels, different thicknesses, different glue types and layers of glue, different exciters - doesn't matter what I do - it sounds good with the exception of the veiled sound. HELP!
I really want to try the EPS but never found a good source - stuck on the XPS. But the gator foam board shows some promise - will try to get hold of a bigger sample.
I actually really like that the we all like different things, have different perspectives and bring different ideas to the table. It really adds to the fun! Thank you all for sharing all your great ideas! And yes - I try many of the ideas I read here in one form or another - many are very good. I also believe the our different room set-up and electronics and not to say the type of music is preferred makes a HUGE impact on preferred panel.
The DAEX30HESF-4 brings more detail and HF than the thrusters. I can easily hear a difference. Before you glue them all up on the XPS, you should just try one with removable tape or something quickly. There is just one thing with it - it sometimes sounds a bit of metalic ringing - Not exactly sure what it since I don't hear it all the time.
I think we use the panels a bit differently. I play them full-range or around 100HZ while I think you cross them higher and can then use smaller panels. In order to get good and clean bass, it's my experience that they need to be as rigid as possible so they will not become 'floppy' - this is especially true when cranking them up while crossing them at 120hz or lower. I can play 1/8" at low volumes or cross them really high - but I agree, the bass doesn't sound good when playing louder. The 1/4 is perhaps too thick and something slightly smaller is what I found is better (after some hard work with the sander). Even on the thicker panels, it doesn't get much of the slam that you will get from a sub, but I have to say as an old electric bass player, that the bass from the panels is very clean and detailed. :thumb:
The more and more I experiment, the more I'm convinced of the multi-panel approach that takes the best from each material option and panel sizes.
But I agree, it would be fun to meet up and compare notes.
Btw: when you do measure your panels can you include the KEF as a reference point for room impact.
Very Interesting! But not sure what conclusions to draw from the KEF comparison- HF drop much sooner and faster as expected and perhaps mitigates the room better in the <200Hz.
What's your take?
Anything else that you could see with less smoothing applied?
Hey Odal! I looked at the responses with less smoothing and nothing else really stood out. To be honest, the panels are measuring better than I imagined overall.
Want to get them outdoors or proper gate these measurement to remove the room but the decay on the panels are so much longer than a normal speaker I'm afraid that it won't give as accurate picture. Reading more tonight on how to measure with REQ for a gated response... always something to do and its taking me away from building... itching to finally make a framed panel and covered with grill cloth, etc., etc.... arg!
So what do you do when you loose them? Only asking so I can try to avoid it, and perhaps we as a group can come up with ways to mod the exciters to be more durable.
> just the adhesive bond failed
Do you mean simply that the exciter fell off the panel ?
The ones that failed on me have been due to the leads coming loose. Do you play the full range. I often do and let the panel decide the roll off, but probably shouldnt do that.
Osssyvan
Something is wrong at the moment ,can't access any pictures at this time?
Steve
Broken lead is what I have seen if I don't count the Ultras that bottomed out. The other thing to point out is that the mounting flange of the heavier 40w exciters are really slippery and glue or VHB tape doesn't stick as well. This is dispite rough sanding the flange. I have had several fall off. On the other hand, my 5W exciter has a much better flange surface that things stick to much better.
I also got one of the DAEX25FHE-4 mounted late last night and WOW! this may be the best one I have tried yet - at least for low volume listening. Very clean and "articulate". Haven't had a chance to play it loud yet and since I am only "allowed" to play xmas music today :roll: I don't yet have a good feel for the bass. Will play around more today when I can sneak in some non-holiday music.
Btw: did you ever damp the back of the exciters to reduce the metallic sound?
Very interesting with your routing grooves in the panels. Are you basing the shapes on the Styrofoam speaker you brought up before?
OB_newbie
It's not just your measurements that show early roll off of 25mm xps ,others also show this,even osssyvan,s last pics show early roll off above a 6k peak,can't see the db scale but it drops heavily,we really need to see some good plots showing hf extension to at least 10k without EQ ,the 25mm does this with no problem .
(http://www.audiocircle.com/image.php?id=107237)
This is an old picture from my gallery ,it is a 25mm 2x5ft EPS panel with the Mic at 12ft into the room,no thinning of the panel in front of the exciter area,notice the drop above 10k then flat to 20k ,this I believe is caused by the thickness of the panel,you will also see the response from about 300hz to 10k is well within +and -2.5db with no EQ .
The ply panels I have also show high output above 10k ,so am surprise to see the drop in HF with osssyvan,s pics,this is why I am a little suspicious of the combination of 30mm exciter and xps ?
Hopefully some new measurements can clear this up
Steve
OB_newbie
It's not just your measurements that show early roll off of 25mm xps ,others also show this,even osssyvan,s last pics show early roll off above a 6k peak,can't see the db scale but it drops heavily,we really need to see some good plots showing hf extension to at least 10k without EQ ,the 25mm does this with no problem .
(http://www.audiocircle.com/image.php?id=107237)
This is an old picture from my gallery ,it is a 25mm 2x5ft EPS panel with the Mic at 12ft into the room,no thinning of the panel in front of the exciter area,notice the drop above 10k then flat to 20k ,this I believe is caused by the thickness of the panel,you will also see the response from about 300hz to 10k is well within +and -2.5db with no EQ .
The ply panels I have also show high output above 10k ,so am surprise to see the drop in HF with osssyvan,s pics,this is why I am a little suspicious of the combination of 30mm exciter and xps ?
Hopefully some new measurements can clear this up
Steve
Sedge,
I was thinking of some XPS. They have it at Home Depot here, in various thicknesses.
I originally wanted to make some stereo panels for a wide band midrange driver, but that project is on the back burner, and I have a 5.1 Receiver and a subwoofer, so figured it would be an interesting experiment. For some reason, I am thinking I will be happier with a home theater setup given that the receiver has DSP functions and the crossover works upto 200hz.
Based on reviews of peoples experiments with DML in HT setups, its worth attempting. Getting them to look decent will probably be a challenge as well.
Note: I am using the PE $3 buyouts - but am planning on upgrading if proof of concept goes as planned.
OB_Newbie,
Thanks for your reply. I did notice that TXATC has a similar HT setup. I took note of the size of his panels. My reasoning for the 200hz XO point was due to my reading of the Mission units which were dependant on the subwoofers ability to go up to 200hz. My existing sub is a small 8" Yamaha I got to compliment a soundbar and it seems to have high output down to about 40hz - good enough for experimenting. It plays up to 200hz.
It's good to know that the panels will not have too much issues with playing lower - may actually allow me to set it up even better than hoped.
In regards to the HF, what suggestions might you have to have them extend without much rolloff? Thinning the panel at the attachment point on the front side seems to be the go to way, and CLS (i believe) on another forum suggested trying a wooden biscuit. It's something to ponder, as I know HF content is important.
Albema - those looks great. Congratulations to finishing them to your liking! I'm sure they sound great.
OB - I also get the peak with the 24W exciters which was an interesting and I guess good surprise on thick ply. I don't have access to the measurements at the moment but think the peak was around 17k
Sedge - you must be close to setting up a museum with all your panels. Always learning something new from your posts. Thank you!
Thanks for the extra inputs, much appreciated.
I agree with the assertion that subs should be crossed low and not high into the high 100's. My open baffles tend to stay under 100, and I love it that way. Once I am certain the panels will work, I will contemplate building a pair of quality subs.
In regards to HF extension, if using XPS, it sounds like I may not to add anything, and just try them full range as is. My lack of measurement equipment is going to be an issue, but will address that in time as well. I have pondered crossing over a small tweeter in the high teens if lacking some of that top end sizzle.
Am I best pursuing an XPS panel? (For the record - and my stupid brain - is XPS the stuff thats pink and dense, or is it the white foam like they pack electronics etc in? - Sorry, I keep getting mixed up)
I am hoping to pick up some panel material soon. I suppose some experimentation will be required before finishing the panels - this allows me time to plot something special for a finish ;)
OB_newbie
Cardboard cc was the first material I used I believe,I could get my hands on all sorts for free at the place I worked at the time,the thinnest was 3mm approx ,this was my favourite.
The main problem with cc was the it sounded like cardboard ,also the sound would travel along the flutes but be blocked going across them ,a bit like the wave breakers that you see at the beach,adding shellac just makes the panel heavier and makes things worse,although I do remember coating the exciter side and noting it helped the sound spread across the back of the panel,coating both sides over damped it,to my ears anyway.
Luckily I discovered eps which is still my favourite ,so far.
I'm afraid I'm going to be showing another couple of panels soon ,one of them my new ply panel and maybe my other harder type panel,if all goes well.
Steve
OB_NEWBIE
Have also pulled out an old eps panel from the loft,an odd shaped one but I haven't thinned the front area ,so could take some measurements then do some thinning and so forth,I now have too many panels to work on at one time,5 in all :duh:
As for EQing panels ,I'm trying to make panels that do not need EQing or very little at most,so if we could have the measurements without EQ it would be very helpful.
These last few weeks or so have opened my eyes about the way hard and heavy panels differ from the lighter eps types ,they both need different mounting to produce their best.
Hopefully if all the tests go well I will post the results,just not 100percent sure yet!
Steve
I thought I had it made with the response within a 5db band from 100hz to above 10k and only one or two db down at about 16k ,so I use measurements only as a guideline,but they can show up bad faults in panels that are less than ideal.
Happy New year all.
Steve
Osssyvan
Hi
Just a few questions.
What was the distance of the Mic.
Is the scale in 5db increments,it's a bit hard to see.
What exciter was used and how was it mounted.
Did you think the sound changed much between sizes and exciter positions.
Thanks for sharing.
Steve
Back home from the Holidays and a big box filled with exciters from my latest order awaited me at home! The new year couldn't have started better. Happy new year everyone!
Interestingly there is still the dip in 8-11k region and cutting the panels seemed to affect the LF surprisingly little.
there is an interesting company site called soundRight.Org.UK they have some nice looking panels for pro work and cardioid subs for PA ,they measure using swept tone and gated pink noise ,there is also some technical papers of interest for panels and subs,also interesting placements for good spread of LF.
There seem to be more stuff out there every time I look.
Steve
Exspec
I presume that you will be able to have all the panels out from the walls 3to4ft?
If the exciters are the same 10watt cheapo exciters I bought some years ago they will be fine with eps and xps and probably ply.
If ply is used they will be struggling with the movie LF below 50HZ ,so xo above this.
Small poly type panels could also work for smaller rooms but more powerful subs would be needed ,and capable of a good quality of sound up to match the panels xo.
Steve
Nice. I have previously tried and given up on the cheap ESP after I had white fluff all over my basement. Your results are encouraging. Is the measurement without sub?
I have the 10" dayton sub and like it too. Just be careful with over driving the plate amp. It burned up and ruined some RCA interconnects for me once.
Can't remember if I posted here or over at Parts Express, but I wonder if we should establish a common, easy and quick to build reference panel with a widely available exciter. This will be a panel that we can all compare against different panel designs. We have difficulty explaining differences because we have no reference to compare to.
Curious what others on this forum think about this idea?
1. Rigidly mounting the panel to a frame results in more low frequency output? Makes sense to me as the overall weight of the panel now includes the wood frame.This is interesting since every time I tried to stiffen the panels on the sides it has moved up the roll-off point creating less bass. I never tried the exact layout as Sedge so what I did maybe can't be compared. My result is perhaps due to the fact my panels are so thick & heavy even before the frame, so I maybe would need an even more powerful exciter to get the LF in a framed config????
I don't know what thickness your ply panels are ,but as you say, your panels sound like they are already heavily into dml mode,extra bracing might not help?
Am a little puzzled why you are using square panels ,is there a reason for this?
What position do you place the exciter to help prevent the stronger standing wave resonances caused by square panels?
As for exciters, my current favourite is the Dayton Audio DAEX30HESF-4. It can managed high SPL without distortion on Re-Board, has plenty of shove for the bass and seems a lot less prone to wobbling and voice coil droop than the DAEX25FHE-4.
Hey Steve - I was a bit hesitant to buy square panels as well but that's the only thing they had pre-cut...and I have to say that close to <10F temperatures with my saw in an unheated garage made my decision easy :-)
I haven't really had time to play them or optimize them much, but I ran a quick sweep before my computer decided to do an automatic upgrade that froze the computer. It follows about the same profile as the 4 x 2 panels which is my favorite size but cuts off the LF little bit higher: ~40Hz, and high end for the 30HESF starts to drop little bit over 10k Hz, and then dips down 10db. The only exciter I have managed to consistently get flat to 20hz on wood is the 25FHE, which has a smaller mount ring. I really think the larger mounting rings on the 40W exciters cuts the HF. I didn't have them free-floating so I had some of the typical dips and peaks in the LF.
I currently have the exciter mounted in monacor position 1 so I can do like for like comparisons, but I have found that the position on wood requires a bit more fine-tuning by ear/mic to get right due to the woods areas with different densities.
I tried a square panel in XPS before like the early ones OB made, and those were not too bad either.
OB_NEWBIE
(http://www.audiocircle.com/image.php?id=45743)
This was the first eps panel I ever bought,as you can see there is a chunk missing from the bottom right side ,this was the part that broke off as I was flying across the car park,away from my car!
This turned out to be lucky,as I had missed running into the parked car's so far,but was running out of space.
I had now managed to stop but I was now flying a 6x4ft Kite above my head ,I managed to walk backwards towards my car dragging the panel with me.
The fun really started when I got back to my car ,as I had to land the panel like a plane by the side of my car and cut it up :lol:
I had to slide across the panel to hold it down while I opened the car and get out the knife ,measuring tape and wood,for a straight edge.
You know that moment after you've managed to finally get it all cut up and in the car,where you stop and nonchalantly look round to see if anyone was watching,I couldn't see anyone ,but always will be a little suspicious,there could have been person's crouching behind car's clutching their stomachs in need of medical attention :oops:
This was the panels setup in my living room,notice the missing piece glued back in place bottom right :thumb:
I'm showing this as the one on the right was large and square,I played a recording of big Ben over these panels and it sounded fantastic , I seem to remember that the larger the panel the less importance the shape made, but we are talking large.
I certainly wouldn't recommend using a small round or square panel as this would cause problems,and if used,offsetting the exciter is a must !
(http://www.audiocircle.com/image.php?id=45750)
To me,the sound came mainly from the centre of the panel and gave a strong image even when walking between and around the panels,the rest of the panel seemed to disappear,these days I tend to forget this and regard this as the norm,that is until I listen to NORMAL speakers ,even very ,very expensive ones at that,but they just don't sound REAL anymore !!!!
I'd sit in front of my speakers and say wow listen to that sweet treble or midrange ,cool,NOW ,with the panels I listen to the music and the instruments,no hifi,no amps,no cables,just live music.
Nowadays when I go to audio shows I just sit there thinking ,oh dear ,what have they done!!!!
Steve
Have just finished the frame on the ply panel,will wait a few days before measuring to see if anything out of the ordinary happens,not yet used a cross brace to support the exciter,but don't expect much to change in the low end as I roll them off heavily below 50hz anyway,but we will see.
Seem to remember the 50-50 eps panel rolled off heavily at about 50hz when the cross brace was installed.
Steve
OB_NEWBIE
The eps I use has no holes in the surface and the surface is quite hard,I haven't a clue what grade it is ,at a guess I'd say probably a medium?
I can only find the low grade in the shops at the moment ,too many holes in the surface for my liking,that's why I'm playing around with others materials at the moment ,so hope they bring back the good stuff as ordering from the manufacturer is expensive.
Mmmmmmm as I'm typing this ,I just thought I could buy the 6x2ft 3mm ply ,and solidly mount in a frame,if it doesn't perform well I can easily saw it in half,then I will still have two 3x2ft panels that I know perform well.
Solidly mounting them on the floor might help the low end performance, the only worry would be that the larger panel might cause a bit of low end boom.
My memory is getting sooooo bad,I just remembered some more mods I was going to try out on the ply ,I will get there eventually ,just too much going on in my life at the moment :duh:
How much pva you apply to the panel is always going to be a personal choice,it's a very much like the light delicate paper cone choice or the doped paper cone or any of the other types of cones ,which do you prefer,all of these cones have their champions,and usually perform well in certain area's ,I think it usually comes down to which annoys you the least,I have used many ways to damp the self noise of panels and cones , but usually you end up damping the sounds you love too :scratch:
Steve
By smaller I meant smaller than the 2.5 x 5 ft. My favorite is 4 x 2ft but I got to say the square 2.5 x 2.5 is growing on me - especially after I made a free hanging stand. Took down some of the hot character of the 30 exciter, not to mention the better WAF amd living room factor... not to be discounted in my house :D.
Since we are talking smaller, I have had some success with small Al and Cu looking plates. 3" x 4". Of course only for the upper frequencies. I havent had a chance to integrate them with bigger panels yet
OB_NEWBIE
I've just come from the diy shop and was examining the low grade eps ,some worse than others .
They tend to have black bits in and gaps in the surface ,my main worry with this quality material is the contact with the exciter foot and unknown air gaps under the surface, a healthy amount of waterproof wood glue on the exciter foot and adjacent panel area would be a good idea ,I think,thick wood glue does not shrink like the pva and would hopefully fill any gaps,good contact with the whole of the panel surface is essential,other than that I can't see why it shouldn't perform well,
Smaller panels like my 9x12inch 3mm xps panels don't really need supporting but do need a higher xo to be able the drive larger rooms .
Using different types of frame for mounting will increase the lower end performance and help drive the room allowing a lower xo,but the cost will be a not so open sounding panel but they can sound good.
(http://www.audiocircle.com/image.php?id=133852)
This is a picture of the 9x12inch ,this is basically a base from a shop bought pizza,in fact all of my small panels were made from different sized and shaped pizza bases ,this was the only way I could get hold of the 3mm material,the only problem was the amount of weight I was putting on :thumb: I a call them the pizza panels range :lol:
You can see some in the background of this picture
(http://www.audiocircle.com/image.php?id=109310)
Mounting two on a single frame was good also, but does not exist anymore,the idea was to mount them in a large line array,I've still got all the panels,too many in fact :oops:
Steve
OB_NEWBIE
I should have pointed out that I do eat the pizza before mounting the exciter,there's a lot less mess that way :thumb:
A very understanding wife :scratch: don't know we're that one came from!
You try sneaking a speaker more than 4inches into the front room ,or a led zeppelin cd ,you'd think world war three had started,I have to make a hasty retreat back to my bomb shelter(music room) :surrender:
If I remember correctly,multiple panels or line arrays work best if listened to from a distance ,the cancellation affects between and in front of the speakers even out with distance.
This is why I probably prefer single panels with single exciters in the smallish rooms I have.
Steve
I bough various router bits and will be routing a round groove between the 2 panels... likely at an smallish angle to vary the response of the panel along with different exciter locations for what I hope is a smoother combined response. This should isolate those frequencies where cancellations would occur.Before you start to go routing everywhere,I think there are a few things you should know.
As for the array aspects. In theory, a 2x6 panel with one exciter ought to operate the same as 2 - 2x3 panels assuming that the entire panel surfaces generate output. Though I have to imagine that a single panel would not have even output over its entire surface?!?! But there will be cancellation either way on both panels. Likely more HF cancellation on the 2 panel array but that depends on the listening distance where they would sum.
I EQ the panels anyway so a slight drop in the HF won't be to much of an issue... hit the panels with a touch HF boost and I'm back in bidness. :)
Before you start to go routing everywhere,I think there are a few things you should know.
Years back now,I had two 12x12inch eps panels on a 12x24inch frame,with a small gap between the free floating edges between them,at the time I only had one of the panels with an exciter on it.
I then attached a small blob of bluetak about the size of a pea in the middle between the panels.
The output from the panel without an exciter on it was pretty much the same as the panel with the exciter on it :scratch: two panels for the price of one exciter (I'm sure manufacturers would love this).
I might as well have straddled the two panels with the one exciter(now there's an idea)'
The only way to stop one exciter interfering with another on the same panel is to saw it totally in half .
You might change the modal pattern on the panel by routing because you have altered the rigidity,but you will not stop one side of the panel from exciting the other,it would be as if the routing was not there.
A 6x2ft panel with one exciter on would have one point source ,two 2x3ft panels would have two point source's,a 6x2ft panel with two exciters on would also have two point source's on.
Each exciter area in itself is nothing more than a flat cone speaker ,what happens to the panel after that first primary pulse is a bonus(dml)
As for EQing a mechanical cancellation on the panel ,once it's gone it's gone,you can only EQ what's left,better not to cancel in the first place.
I hope this helps.
Steve
Cool. Looking fwd to hear about your results.
Btw rightly or wrongly, I have always gone for the principle to gradually thin the panels towards the edge on large panels. Idea is the "energy principle" to make it easier to propagate the wave the further away from the source. Exception is thin at exciter location
I'm not sure about thinning the panel with eps as it would probably loose some of its rigidity,plus I haven't noticed any problems with the sound moving through eps,quite the opposite in fact.+1 on the EPS. The 3/4" low grade I'm testing with is incredibly light and likely UNDERDAMPED. XPS I've also felt to be a little over damped but you realize this more clearly after using the low grade EPS. I assume a higher density EPS will move closer to XPS but appears that it will have the upper hand over XPS... lighter and more resilient... more lively.
The 5mm xps I would describe as a lossy panel,heavily direct radiating with a not so high output dml mode,even more so when I sanded the outer 2inches or so,this helps soften the reflections I think.
I too am not keen on putting eps in frames ,but ply seems to benefit from it,there's more life and detail ,they are now more spacious sounding ,I'd go as far as saying these are the best nxt dml bmr panels I have ever heard (except for my poly +sub combo
I have spent the last few evenings optimising my Re-Board panels, and I have to say the results are just amazing :o.
Currently the Re-Board panels are simply hung from the ceiling, with one DAEX30HESF-4 and a DEAX25TP on each panel. I've been using 2 Breeze Audio TPA3116 amplifiers to power them, with a 2x4 MiniDSP handling the crossover duties (and a fair bit of EQ too). The crossover is set at 3kHz, and the combination is noticeably cleaner, smoother and more extended than a DAEX30HESF-4 on its own. The DAEX30HESF-4s also have a high pass filter at 80Hz, and are crossed over to a big tapped pipe subwoofer of my own design.
The whole thing just sounds so huge and effortless, detailed, clean and fast. It just doesn't seem to distort (I measured 120dB at the mouth of the sub before the neighbour guilt kicked in).
I'm sure it could be improved with a frame to support the back of the exciters, and I am wondering if I can add another DAEX30HESF-4 in series per panel for some more headroom and kick in the upper bass (hopefully there should not be any negative effect on the higher frequencies because of the 3Khz low pass filter). As the volume increased the DAEX30HESF-4s did get quite warm, but the DEAX25TPs stayed cool.
One thing I did notice is the the panel's low frequency response was reduced when hanging compared to having a corner clamped in a vice as I had had them before. I guess that makes sense as the bench would have been acting as a bit of a baffle, and they were a bit further away when hanging.
Also, with spoken word there is a tiny bit of sibilance, but that is getting very picky.
I kind of wish there were more (interested) people around to show it off to :)
(http://www.audiocircle.com/image.php?id=136650)
(http://www.audiocircle.com/image.php?id=136651)
(http://www.audiocircle.com/image.php?id=136653)
Am now entering stage one of this project, I have glued the exciter to the 6x2ft panel and now await it to dry ,so as I can move it out of the kitchen, hopefully it won't get knocked about!
I have used the monacor position and will see how it compares to the solidly mounted 2x3ft panel.
I will probably have to stand the panel on some foam pads as I don't have anything tall enough to hang them from ,I can hold the panel for short tests .
Will let you know how it goes after a few days drying.
Steve
To my ears the smaller panel also sounds livelier ,but this could just mean that the larger free edged panel needs a more powerful exciter?
Scott
I use pva to glue on the exciters .I usually scuff the exciter foot with sand paper first.
Steve
Its not commercially available as far as I know, it comes from friends that work at Wright Patt AFB in areas that they cant even discuss what they do.Sounds a bit like the X files ,if you suddenly disappear we will know what's happened to you!!!
Testing the first customers art panels. They sent the images which I had printed to 16 x 20. Mounted the images to the panels using 3m 90 spray glue and then to the frames using 3m VHB 5952 foam insulation tape. Used the Dayton Audio DAEX25VT-4 exciter ( helps that their showroom is down the road from my house), with a 199uf high pass capacitor as the customer was going to use these in a surround sound system with subwoofers. You really can't tell from this iphone recording, but they do sound pretty good.That looks extremely neat! :D
https://www.youtube.com/watch?v=Qs9Bmri_mqQ
I'm building another customer pair this week. I will post picks of the construction. I'm making a pair of 11 x 14 with a new 2mm panel which should give even better high end response.
Are you using any type of glass or lamination in front of the images? It appears in some photos there is a bit of glare, but cannot tell. I have been working on a similar project over the past little bit and am hoping to be able to join you in sharing notes soon. Is your panel material something readily available or is it exotic and expensive AF?
What I see on the drawing is a rectangle with rounded corners. That does not tell me if the oval shape is better than a rectangle for DML speakers.
At this stage of my projects, I think I should better use an Infraflex for bass, and a DML for mid-treble.
Oh my God, what did I say? :slap: Now somebody is going to ask me to
explain what is an Infraflex... Pol, could you do that for me please? :beer:
Cut to the chase, I would like to try Dayton exciters as midrange ~200-~10kHz with sub and supertweeter assist, probably OB at both extremes, active XO possible at 200-250, passive 8-10kHz. My question, what are the minimum dimensions of an EPS, XPS or thin ply panel to "easily" achieve that range? Am I better with a thin panel?
Ozziozzi
I won't try to explain what is an InfraFlex, though it may sound good, it is backed by a very fuzzy theory... LOL
POL
Hello,
Yes, it's quite a long time since my last post, and no, I moved to Madagascar, so I sold my one piece stereo panel, and I have rebuild a tryptic... 5m² LOL, (yes! I'm single, in a wood cabin , in the wild)
(http://www.audiocircle.com/image.php?id=155951)
That looks like an amazing set-up. I never tried a corner like that before. How do you like it vs having it in the middle of a wall or more out in the room?
As far as heavily damped panels plastered into walls and skimmed with plaster,and heavily damped picture panels in picture frames with pictures in front of them nailed to a wall ,what can I say,except that the sound from the panel will be compromised,not that they won't sound ok,just not as good as they could sound .
Huge free floating panels are amazingly good .
Oh to be single ,in a wood cabin in the wild :thumb:
Pol
By pseudo infinite baffle ,are they trying to minimise reflections from the edge to lessen the dml effect or are they trying to disperse the reflections to breakup standing waves ? Or something else?
What size and material are you thinking of using ?
Steve
The exciter looks like it might be a little heavy ,and might not be designed to support itself for long periods ,hence the mounting lugs.
While I was testing ply with exciter I put exciter down on a piece of polystyrene panel (ex broccoli box from supermarket !!! ) and it played a lot louder. I guess ply density is higher than XPS. Did you find the same result re efficiency?Yes, using ply definitely reduces the efficiency a lot, but unless you want to play really loud it isn't really a problem. I like the character of the birch ply sound a lot so for me it is still really good (my preferred material). I use 1/4in which is thicker ply than you use. I found that the thinner ply warped and moved too much when playing loud.
Well said. I agree 100%. That is my experience exactly. I started with 8 exciters per panel and now use only one.
One of the most common questions is what size panel to use.....Some will say the bigger the better but that is not always the case as panel size will depend on the type of exciter and the amount of exciters used on each panel.....a very small 13mm 3 watt exciter can be used on a smaller thinner sized panel even as small as 8 inches while a 32mm 40watt rms exciter will be over kill on the same size panel. On the other hand a 13mm 3 watt exciter on a 2ft.X4ft. panel is not enough to vibrate such a large panel while the 32mm 40 watt exciter should be enough. So like I said panel size is predicated on the type and the amount of exciters used per panel.
Bigger higher power exciters can be used on bigger and thicker panels.
Smaller less power exciters can be used on smaller and thinner panels.
Multiple exciters can be used on bigger panels.
I beg to have a different view, let me explain this
About ten years ago, when I started to cut & try with DML exciters, my opinion was exactly the same as yours. At this moment, my supposition based on what I ought to know from previous experimentations with line_array multi-drivers was, that in order to move a big panel, I would need a certain amount of Watts, and just because at this moment, only smalls exciters where available, I guesstimated that a minimim of 4 to 8 exciters was requested.
How wrong I was, and why? because I had in mind piston loudspeakers, Distributed Modes loudspeakers are a different kind of beasts.
A small motor will move any panel, tiny or huge the same way, and bass depend only of the radiation surface available (acoustic impedance). Obviously a bigger motor will move the panel deeper, but not lower in frequency.
Conclusion, you can put a single 5w exciter on a huge panel, and reach quite low in bass range, and if you need 9dB more loudness, just pick a 40w model.
But the important thing to keep in mind is that by putting a group of exciters on a panel , it's no more a DML system, it's a kind of hybrid monster.
POL
Hi, Odal3....Like Ive stated above my DML Panels mimic Bertagni speakers. I am currently using a 5.1 system of ALL DML panels including the sub. A DML panel sub is just a DML panel utilizing a sub amp.
Got it. Thanks for clarifying. It's fun and very rewarding, isn't?
Basically any type of exciter will move/vibrate any size panel BUT the difference is in the out put of the vibrations of each type of exciter which can be due to size, design and power handling. More vibrations equals more loudness more loudness equals more audible bass at moderate volume levels....a 13mm 2-3 watt exciter bass out put is very low and will start to distort at moderate volume levels when ran full range due to bass restriction limits.
I believe there is a certain OPTIMAL RATIO of exciter vibration out put and panel size like I mentioned in my above post.....From my experiments these 3 things come into play when determining bass output...1. Type of Exciter design/size/power handling...2. Type of panel material (EPS for me) 3. Panel size as well as panel thickness.
I see that you are still thinking in terms of plane pistons, where a bass loudspeaker should have great excursions to make low frequencies.
Let me ask a simple question: Between a 1 meter square speaker with a 1 millimeter excursion and a 10cm speaker with a 10cm excursion, although they move the same volume of air, which is the more likely to reach low frequencies? and why?
Only because of their acoustic impedance, that of the air and the radiation impedance of the transducers, as well as their mutual adaptation.
with DMLs a small transducer will reach exactly the same bass frequency than a bigger one on the same panel, it will simply output less volume.
but on the other side a big transducer wont get very high in frequency, because of his weight and the diameter of the voice coil.
I am using 5 square meters of panels with tiny 5W transducers, & full range...
Looking at the bertagni speakers ,they are a heavily clamped panel with thinning in area's, the lower end below 500hz is handled by the larger clamped panel ,in the YouTube video it does seem to act as a clapped piston at low frequencies hence the large clamped frame and magnet .
I would expect the sound to be similar to a standard cone type speaker ,and very different sounding from a free floating panel.
Clamping a polystyrene panel does not sound good to me ,clamping something like 3mm plywood can improve the sound and output,they react differently to the same procedure.
A single 10watt 25mm exciter freely mounted on a ,let's say 3ftx7ftx 1inch poly panel would fill a house let alone a room with a fullrange of sound from 20hz to 20k(as long as room and panel cancellations in the 100hz to 300hz have been taken care of) a 2x4ft panel does a good job too.
Personally though I would use a low frequency driver to take the strain of the larger movements from the panels.
Steve
Bendingwave
I did look at the video link's you posted ,I could not view newbie,s video as it is unavailable !
I have problems with the other video as the sound did not match the movement of the camera so am unsure how this recording was made?
The YouTube video you previously posted gave a much better idea of how the bertagni speakers sounded in a real room.
Yes they do sound good ,but the drive units used are very similar to bmr units but larger,and as such will suffer the same problems as standard drive units.
Steve
yawl can judge for yourselves which sound you prefer better.
Bertagni speakers> https://www.youtube.com/watch?v=U-OQz_AuzB8&t=40s
Rich (aka OBNewbie) free floating panels with EQ> https://www.youtube.com/watch?v=To3IOYxTFKw
So,what you are saying is that free floating panels sound bad ,so we should all go out and buy bmr units and hey presto all problems solved ?
The video's play on my computer but not my tablets, only trouble is i can't get much volume on my computer !
I used headphones when listening to the YouTube video on the tablet and when he moved left to right the sound stayed dead center you would also expect the sound to change when moving over tweeters and midrange drivers,also when the music stopped so did all the sound,dead silence ,even though there were other people and a dog in the room ?
Comparing newbie,s small panel (which would not be my first choice for best sounding panel) to a full range panel type speaker with open panel sub and tweeters is not a good match.
You would have to add a sub plus tweeters and xo, playing a midrange unit only ,would sound odd !
From experience if you clamp a poly type panel you might as well buy a bmr , as the sound is totally destroyed by over damping !
Steve
The Bertagni video is clearly a sound / video remix with a soundtrack that does not match the actual recording of the microphone. If we run a vectorscope software in background we see that the separation of the channels and their position in the space does not change at all. Juste a small scam
POL
I do a lot of sound editing for my pleasure and for measurements and I can guarantee 100% that this track does not stick with the movements of the microphone. No phase changes between the left and right channels, no sound balance change, and at the end the sound stop one second after passing over the Bertagni because the guy awkwardly tried to make the end of the sound track coincide with The passage from the front to the rear being aware that there must be a sound attenuation at this moment. And last there is absolutely no back ground echoes from the room, :green: A huge joke.
Yes, I have been to his Ebay page and have read his post
"
I did make a video, with them playing !!
Go to YOUTUBE .......Search Bertagni Panel Speakers, you will see them playing with a warm rich sound. There is no rattles, bass is deep and sound amazing.
In the video, ( taken from a cell phone, the color is not that great, but you can see, and hear them perfectly.) "
I have yet to see a cellphone able to take such a great stereo recording, ICH LACHE MICH TOT !!!
(http://www.audiocircle.com/image.php?id=161502)
POL
I wont step in because I am not the sheriff of this planet :roll:, and I do not aim at paying 650$ for a couple of sound transducers half a century old.
But I do know when I see a forgery.
And because the sound track is a little scam, I am suspicious of the whole annonce, there is zero picture of the transducers and of the inside of the loudspeakers. :duh:
You should guess why...
POL
Ahem. no need to get so excited about exciters or lack thereof :nono:
Maybe we should put it to the panel :lol:
Ok this will be my last post on this boring subject:
Words have a meaning and I understand perfectly that you do not have the knowledge to exploit the informations that I already gave, the phase and balance of the left and right channels never vary throughout the video, as shown by the display of the vectorscope that I posted next to the page of the video. Anyone with a bit of audio editing experience can understand what I'm talking about. And I'm still waiting for be shown a cellphone capable of making a perfectly stable stereo recording of this quality while the camera is swept from right to left, especially without capturing any echo of the room or street noise. This simply does not exist.
A transducer that is not shown in photos is a transducer that is rusted or damaged, Ebay is full of announcement of ruins on sale for staggering prices.
POL
Here is another thing I wanted to touch upon with these DML panels technology working differently then conventional cone speakers......When recording sound on a conventional cone 2-4 way speakers moving the camera to the tweeter will change the sound for the mere fact that they are SEPARATE drivers....Bertagni speakers use two exciters one full range while the other is high passed at 1k.....The reason why one wont hear the change in sound when moving from the full range transducer to the high pass transducer is because they are both radiating/vibrating there combined frequencies on the SAME PLANE/PANEL....Those that do not know this do not fully understand exciter technology as this is the real nature of the beast called exciters. 8)
Bendingwave
Tectonics panels xo at about 6k or so to a single separate tweeter off the panel ,this is to minimise combing effects between the HF of the exciter's ,ie minimising the cancellations of sound waves traveling through the panels and those traveling through the air between the exciter's.
As for not being able to hear two exciter's (tweeters) on a single panel, it is very easy to hear the sounds from the exciter area and to measure with a test mic the beaming from the exciter voice coil area .
Over the years I have used a few different methods to reduce the beaming in the HF ,blutack is the easy but not the best option.
It is always good to remember that the first pulse wave (tectonic call this the primary wave) will always come from the coil ,traveling into the centre of the voice coil area and out away from the voice coil area,what ever happens to this primary wave after this is up to you ,but it will always be there !
Steve
Hi, Odal3....Like Ive stated above my DML Panels mimic Bertagni speakers. I am currently using a 5.1 system of ALL DML panels including the sub. A DML panel sub is just a DML panel utilizing a sub amp.You keep mentioning that YouTube video ,I have no interest in this video at all.
Bertagni speakers technology are basically very similar to NXT's so called BMR technology which is basically just a exciter attached to a brace/spline which in turn is attached to a frame with some sort of surround (usually foam and or rubber) material holding the panel in place on the frame....Bertagni speakers just do it on a much larger scale panel.....Another design very similar to Exciter/BMR technology are the old school Sony APM square flat speakers.
One of the most common mistakes is that most DIY DML panel designs do not use a spline/brace attached to a frame. A spline attached to a frame is very important as the back of the exciter needs something to hold it place for it to actually push/move the panel material at higher excursions...it will also increase accuracy, clarity/treble.
Most people start of utilizing Rich M's designs on parts express gallery (aka OB newbie on this site) which is just a basic start up design into DML technology....Unless a DML panel is done right one wont ever experience a DML panels TRUE POTENTIAL.
Here is a review of Bertagnis flag ship DML speakers the SM 300 just so one can get a glimpse at there potential when perfected like Bertagni designs.
http://www.hifi-classic.net/review/bes-sm300-289.html
http://www.townwire.net/bes_d120%27s.htm
http://www.audioimprov.com/AudioImprov/Speakers/Entries/2012/6/15_Bertagni_SM-275_restoration.html
https://www.youtube.com/watch?v=r5eqcmHW3Vs&t=641s
On the youtube vid you can see Bertagnis design of using a frame/spline to hold the exciter in place.
You keep mentioning that YouTube video ,I have no interest in this video at all.
Why not concentrate on the bertagni speakers in this video which you posted ,where the sound changes as he moves around the room.
Is there a problem with this ?
Bendingwave
I'm sorry I cannot continue with this conversation ,I am lost for words.
It gets worse with every post.
Goodbye
Steve
Hey OZZ, yes I treat the front and back with PVA/water mix but I do not use the 50/50 ratio instead I use the 70/30 ratio of 70% water and 30% glue....I also paint only the front of the panels with high gloss enamel oil based paint 1 coat.
I use the frost king 3/4 inch foam where one side of the foam is sticky so you only need to use glue on the other side. Foam is mounted on the back edge of the panel that will be mounted to the frame....There is 2 ways you can mount the panels to the surrounds....The first way is to modify the edges of the panels like in this picture > http://mlm-s2-p.mlstatic.com/bafles-raros-bertagni-electroacoustic-systems-no-tecnics-12737-MLM20066287131_032014-F.jpg
The second way which is easier is to just modify the foam buy cutting sections of the foam and spacing them out 2 inches apart evenly around the back side edge of panel but do not use any foam on or too close to the corners....yes I round the corners I just cut off the very tip of the corner and sand it evenly.....The exciters with the threaded screw holes I use screws but the ones without the screw holes I use adhesive to secure them to the spine.
The DAEX25FHE is one of the best bang for the buck over all exciter....Even its terminals are better then other exciters as other exciters the hole to wire them is so small I cant barely fit 20 gauge wire. lol...The DAEX25FHE is also a vented exciter so the sound will radiate from the back of the exciter as well. You can change the sound of the exciter by taping up and covering some of the vents like every other vent....covering up the vents can increase accuracy in sound but covering up too much of the vents will decrease that open spaciousness so its just personal preference. I only have 1 pair of those exciters as my design requires 2 exciters so I need to use mostly 8ohm exciters....I do not know why P.E. makes more 4ohm exciters then 8ohms.
Ah yes I have seen those type of speakers before, if I remember correctly they are the Teac brand utilizing NXT technology/exciters...I seen one on craigslist for $10.00 but it was sold...Seen another but it came with the receiver/cd player for $40.00 but I only wanted the speakers so I did not buy it.
Bendingwave
I must point out that telling people to cover up vent holes without warning them that doing so could destroy there exciter's and also melt the panel. It's like not putting water in your car radiator because you think it sounds better ?
The vents are there for forced cooling of the coils and to reduce noise ,bertagni new he had to reduce the temperature of his coils or he would be doing serious repair jobs to melted poly panels.
As for making all the difference to the sound from front to the back :duh:
I have used exciter's with there vent holes blocked mounted on spines ,for test reason's only ,with very little difference in sound if any? Although a ten watt exciter will go down to 20hz and lower on a large panel,but if you mount the exciter on a spine you will probably find it will roll off fast at about 40hz .
Bertagnis work as a piston in this area ,a free floating panel as POL said, does not !
Once again Having two exciter's on a single panel will interfere with each other( combing effects).
Tectonics use four exciter's to a panel ,and use two panels,the exciter's look as if they are using nxt positioning.
Tectonics minimise combing by xo ing to a ribbon tweeter at about 6k or so.
This would mean no combing effects above 6k.
Steve
Bendingwave
You chose not to take the easy root and just say,sorry ,yes I should have mentioned that blocking the vent holes could damage your pride and joy.
Instead you made a very long post blaming everyone else if they damage the exciters .
You should not presume that everybody knows what the holes are on certain drive units.small exciters only have one vent hole at the rear ,they look hear to get good safe advice.
Some maybe using low power exciters on heavy ply panels for instance ,already stretched to the limit temperature wise ,recommending blocking the vent hole to make((supposedly) them sound better,should always be with a warning !!
Can you also explain how utilising bertagnis method of using two exciters on a panel with little combing effects is done ?
Yes I have heard nxt panels.
Zygadr changed his mind later to using single exciter poly panes.
Steve
This is my final response to Bendingwave .
I am not prepared to continue a dialogue that is both abusive, and offensively sexist and misogynistic in tone.
Steve
I noticed with some of the higher powered exciters that they have a horn or waveguide as part of the cooling vent.
(http://www.audiocircle.com/image.php?id=162031)
I wonder if you could use this same idea to boost the output from the rear of other exciters. Scuse crude drawing, but you get the idea
(http://www.audiocircle.com/image.php?id=162032)
Ozziozzi
Here's the pics I promised months ago.
(http://www.audiocircle.com/image.php?id=47810)
(http://www.audiocircle.com/image.php?id=47811)
(http://www.audiocircle.com/image.php?id=47812)
(http://www.audiocircle.com/image.php?id=47813)
I didn't include a picture of the other speaker. That one has the warping on the 2 corners that really angered me. You really have to look to see it, but I am still pissed regardless. It's about half an inch out of whack on the two diagonal corners.
One of the down falls with experimenting with these exciter technology is that you will be throwing away a lot of your failures in the beginning just from attaching and retaching of the exciters as either the exciter will break or the panel will break or both when trying to detach them as one or both of them will give and I prefer to break the panel material instead of the exciter when trying to remove them....I use a thin knife or xacto blade to remove them.
Also I dont like the 3m adhesive tape that comes with the exciters as they are not permenant and over time will come off plus like I said even the type of adhesive used to attach a exciter to a panel can effect its sound....my adhesive of choice is 2 part EPOXY, prefer the 5 minute epoxy so it sticks fast.
Also someone on this topic mentioned about using GRAPHENE material which is very very expensive, way more expensive then even nomex honeycombs.
Bendingwave, if you listen to an intimate acoustic jazz trio, for instance, often the piano, bass and drums are only amplified (if at all) by a PA system. and if they are well balanced, the players don't drown out each other.
It is only when acoustic bass or drums are close miced and played through a powerful PA with usually a large amps and subwoofer that there really is "slam" in the bass, drums and even other instruments. Of course, with rock or all electric bands electric bass has slam from the player's own amp and then that is amplified (usually at stadium levels even in an enclosed space). Do you remember the movie Spinal Tap where the stage amps were turned up to 11. :lol: I used to drive a PA for a 10 piece band and everyone always wanted to be louder than everyone else in the foldback and house mix!!!! After a while you just run out of headroom, even with a powerful PA, and just end up with distortion.
For acoustic groups DML loudspeakers CAN produce the **actual** level of the performance for someone seated in the audience. Unfortunately, a lot of people are used to highly amplified music at concerts and try to recreate that SPL at home and they complain about lack of bass output. I am as guilty as anyone in complaining about this, but it is a false expectation. If you want concert levels get a good pair of headphones.
Just my 2c worth.
Ozziozzi
Odal3 have you tried the Ultra hard density EPS?
No - never had a chance. I have only used what I can found at the US home improvement stores (Home Depot, Lowes, etc.)
Re bass - my experience is that bass is relative to size of panel, not necessarily power rating of exciter - the bigger panel the lower bass.
I tried once putting multiple 40W exciter like I saw in one of the tectonic videos - the 1/4in birch panel was not stiff enough resulting in a lot of rattle due to "over-bending". Perhaps you need a different design altogether if you have very powerful exciters. ?
I noticed with some of the higher powered exciters that they have a horn or waveguide as part of the cooling vent.
(http://www.audiocircle.com/image.php?id=162031)
I wonder if you could use this same idea to boost the output from the rear of other exciters. Scuse crude drawing, but you get the idea
(http://www.audiocircle.com/image.php?id=162032)
Ozziozzi
Since my daughter has gotten into Karaoke( :?) I now have a reasonable mic to do measurements with and have been VERY impressed with the linearity one can achieve.
What caracterize a pistonic driver is that the moving surface is less than a quarter wave so it moves in-phase all along his range of frequency and it has a peripheral suspension (external spider) which gives him a so-called aperiodic behaviour, this is pure theory, in the real world, pistonic loudspeakers have a frequency range which is quite short (3 octaves) and turn to modal as the frequency rises. A DML does exactly the contrary, modal everywhere (6 or 7 octaves) but poor pistonic in low frequencies because of the lack of excursion and modes.
POL
Ive been obsessed with these DML panels for the past 2-3 years as you can get sound quality that equals speakers costing 1-2k but at a fraction of the cost.Wait, DML panels can only sound like panels costing 1-2k? That's pretty disappointing :(, from the way people talk about them I would of thought they sounded much better.
Wait, DML panels can only sound like panels costing 1-2k? That's pretty disappointing :(, from the way people talk about them I would of thought they sounded much better.
For $1000 I could make a speaker using traditional technology that sounds like a $10,000 speaker or more, I haven't heard a 1-2k speaker that sounded anywhere near as good as my HD800 headphones.
I'm guessing DML isn't for me?
This is when one takes bending wave technology very seriously with vast amounts of resources and technology to back them up.
https://www.youtube.com/watch?v=YOy4XmVICRw&t=127s
https://www.youtube.com/watch?v=XgoMMihVVu4
https://www.youtube.com/watch?v=n2Lq19U7t8E
https://www.youtube.com/watch?v=QGFFKe-7SYA
Whats odd is your FIRST post on this forum, instead of actually contributing something useful to this thread, is too nit pick and argue with me about something so insignificant?In what way was I being nit-picky or argumentative? I asked a question to get a quantitative understanding of BML sound.
In what way was I being nit-picky or argumentative? This is the only active forum still discussing this topic and I spent an entire day reading through old forum threads on the subject.
I've seen very little objective observations on the sonic quality of DMLs in all the years worth of posts that I've read. Other than Ziggys enthusiasm it's mostly been discussion on theory.
I wanted to hear your response to what I said to decide whether or not I should devote time or effort into this endeavor.
Is there no workaround? What about my suggestion of using many small panels?
Doesn't an accumulation of small panels still move enough air to create decent bass? I'm sorry I don't know what you mean about low modes "i haven't had any more time yet to do any further research into this specific technology. I can't seem to find what you mean by low mean through google.
Yeah I'd like to hear an updated consolidation of how-to information if there is one.
The thing I hate about long threads like this is they are filled with so much information scattered throughout the entire thing.
Has anyone made something like a checklist of consensus?
Off the top of my head I can think of a few questions such as:
Are lower powered modules more detailed, lower distortion?
Can many smaller panels be used to form a giant panel with the same effect? Or perhaps to a better effect? I assume based on the ability to remain small, which is conventionally good for tweeters, while still being able to consolidate into a larger entity for lower frequencies.
Is there a consensus on the best sounding brand/model?
What panel material is best overall?
In 2009 Ziggy stated that taking the exciters out of their shell was the way to go, are we still doing that?
I'm sure I have lots more questions but those are the most pressing ones.
If someone has a guide somewhere that would be great too.
When Zigadr was live I used to post in this thread til I realize there was no Gatorfoam in my country.
What panel and exciters you guys are using today?
Thanks
I for one find the 'hobby' of tinkering with DMLs as enjoyable as listening to 'em
YMMV.
Crackie welcome to the this thread........What I want to know is what is the definition of the word pistonic?.... Dont all drivers have moving coils and or move/vibrate in and out in a pistonic fashion to varying degrees? IF not, when EXACTLY does a driver become pistonic, what excursion levels of Xmax is required for a driver to be labeled as pistonic?Thanks for the welcome(s). Apologies for the delay responding.
A sub driver aspires to be highly pistonic because it needs that excursion to produce a good amount of bass, while a mid range driver and or tweeter does not aspire nor requires to have a high degree of pistonic/excursion movement, since they are only reproducing the high frequencies.
In all honesty, I do not think graphenes are the way to go at present. There are too many unanswered questions.
It may have load bearing strength, as a monocrystalline monolayer, but what happens to it in the form as a 'bulk' material?
What happens to it if you drop it?
How does it respond to changes in temperature & humidity?
Is it resistant to chemical "attack" (ie: glue)
In short, how does it respond to "home" environment?
Now I am SURE there must be a material scientist out there with the answers to all these questions, and the answers may well show that graphene is indeed ideal for DML panels but my pragmatic view is that easily 'pretty damn good' speakers can be made from 'pretty damn cheap' materials.
Even if one wants to go super exotic, then a 2foot x 4foot carbonfibre/nomex honeycomb sandwich can probably be had for about £500 or less: this would still be pretty much The Bleeding Edge.
Maybe as I get older I hear less (but listen more...?) - and so get less bothered about chasing the tiniest % differences 'fancy' kit/wires/DACs etc bring.
That being said: semitransparent, impossibly thin, rigid floorstanding panels would be insanely cool. Especially if we could use LASERs to drive them.
Ben
Thanks for the welcome(s). Apologies for the delay responding.
For the sake of discussion, we can think of a moving coil driver's voice coil and an exciter's voice coil behaving in the same way and responding faithfully to the AC applied at its input. The cone motion on an 'ideal' moving coil driver would faithfully reproduce the input AC signal and apply pressure ( or not ) to the air in front of the cone. State of the art moving coil drivers from people like Accuton, Raidho, SEAS, etc variously use metal alloys, ceramics diamond and are notionally pistonic at the lower end of their bandwidth; they all cease to be pistons at the high end and become non linear. The point at which this happens is easy to determine by reviewing their CSD or distortion characteristics. A good old impedance curve also gives away many clues about non linearity.
Regarding your point about bass drivers needing to be pistonic and midranges/tweeters not needing to be pistonic, I think each transducer should behave pistonically ( over the chosen operating bandwidth ). IMHO the primary reason that different driver materials sound the way they do is due to their breakup behaviour when they are no longer behaving like pistons. When they are not pistonic they become modal, like a DML.
Regarding best panel materials; internal damping is the killer of HF so softer cores are poor. The best foam cores, such as Rohacell, have very high compressive strength and work well. Honeycombe cores ( aluminium and Nomex ) are better still. Amina and Podium use honeycombs for a reason; I've met Shelley Katz from Podium several times and did some work for him early in the 'layered sound' project; the big Podium products sound great and have received some great reviews. They are very simple things though. High quality Nomex honeycomb cored panels and 4 decent tulip exciters; exciter technology has since moved on and, with a little research, its possible to source similar quality panel materials too.
DMLs modal panel behaviour cause them to be very labour intensive to measure. Small microphone position and/or distance changes can have significant changes in the measurement. It is conventional to measure a moving coil at 1W/1m somewhere between HF and mid driver axes, this will only give you a small snapshot of a DMLs true output. A polar plot or some form of averaging is needed to really see how a panel is behaving.
I understand the DML concept thanks for your explanation.....Rohacell seems to be pretty expensive like the nomex honeycomb materials hence why a lot of people wont use it to experiment on....There are 12 types of Rohacell listed on there site ,which one is the best suited for DML panels?
Also since you have worked at Amina, what is the frequency response of the Amina honeycomb panels? Any NXT or Amina white paper/ariticles you care to share with us? Thanks.
For a DML the standard industrial grade (IG ) is fine; the numbers in their product range identify are the material's density. 31 IG is the lowest density and therefore the highest sensitivity for 'our' application. IG51 would fine too. There are many other low mass thermal insulation foams which can work extremely well too.......unfortunately it is often difficult to find them in the optimum thicknesses though. 4-6mm is optimal for large full range panels.
There are alternative honeycomb panels which cost less than similar Nomex and Aluminium alternatives.
http://www.coretexgroup.co.uk/Honeycombcore.html
Amina's panel standard panel size dictates the response at the low end. There is a high pass to protect the panels and improve power handling; low end is deliberately limited to -3dB at 90Hz. The exciters used are Amina's own designs, are assembled in-house and they aren't available to the public. The specific HF exciter extends HF to above 40Khz. As I mentioned in earlier, excessive internal damping i.e soft cores are the killer of HF.
http://aminasound.com/file-directory/product/loudspeakers/mobius/datasheet/Mobius5_Datasheet.pdf
I don't have any white papers, sorry.
So how does rohacell panel sound compare to that of nomex or aluminum honeycomb panels? Which one do you think sounds better?The best PMI foams like Rohacell are still behind honeycombs when is comes to compreesion strength; consequently their HF rolls off. Amina's HF exciter does not extend to 40kHz on a Rohacell panel.
How does those cortex honeycomb panels compare with the nomex/aluminum panels in terms of sound quality? Which one do you think sounds better?
So amina panels are more like sat speakers which require a sub for the low end?....wow a exciter that extends to 40khz, now that is the type of exciter I want and need.
So how does rohacell panel sound compare to that of nomex or aluminum honeycomb panels? Which one do you think sounds better?Apologies, I forgot a couple of points you raised. The coretex panels' compressive strength is behind the aluminium and Nomex but not by much; the coretex type panels had Mylar skins with a thinn damping scrim in between. I thought they sounded great. Nomex core with Mylar type skins ( Podium ) is excellent and probably my favourite subjectively.
How does those cortex honeycomb panels compare with the nomex/aluminum panels in terms of sound quality? Which one do you think sounds better?
So amina panels are more like sat speakers which require a sub for the low end?....wow a exciter that extends to 40khz, now that is the type of exciter I want and need.
Hey Crackie thanks for all the info appreciate it.....I have a few more questions what is the best adhesive to use and what or where can one purchase the type of mylar skin used on the podiums, thanks.The adhesives used for commercial panel construction are typically supplied in sheet form and require the correct combination of heat, time and pressure during the curing process. Different adhesives are needed for different cores and skins; for example aluminium oxidises in air very quickly and becomes difficult to bond to and some 'polymer' skins have low surface energy and are inherently difficult to bond. This link explains in more detail https://compositesuk.co.uk/system/files/documents/Adhesive%20bonding%20of%20composites_0.pdf
I watched that video several times over the past few days. The presenter went to great lengths to illustrate his findings.
I started playing with DML's after reading the late Zygadr's original post in 2009.
He had such enthusiasm for his new found project, I couldn't help but get involved and became a believer.
So, 9 years later and I'm still messing with these things on and off. I still don't have them figured out, but I did accumulate some observations over the years.
First of all, one exciter on one panel seems to give the most predictable results.
My first pair of working prototypes consisted of cheap, low power exciters I bought in bulk from Parts Express.
I constructed frames with 4 sections, the panels were 12x12 inches and mounted into each section with duct tape.
So, with one 5 watt exciter per panel, I had a 20 watt power handling speaker.
I crossed them over at 150 hz 4th order hp filter and used a subwoofer. If you're hoping to get tactile bass with a very large panel driven by multiple exciters, forget it. It's not going to happen!
Getting back to that video.
In the second half he shows resonant nodes with suger and how the pattern changes with frequency.
I recently ran pink noise through a panel and observed it with a spectrum analyzer.
At one meter the spectrum analyzer shows a fairly predictable pattern. What I found interesting was that bringing the test mic within an inch of the panel, and moving it around the surface, showed definate signs of considerable comb filtering.
1/6 per octave looked like the teeth on a saw as the mic was moved around.
Here's the thing about that. Do the nodes and comb filtering combine in a predictable caos as distance increases?
I don't know, I'm not a physics expert.
Demonstrations have shown that DML's are nearly immune to feedback and stereo imaging can be heard and appreciated in very large venues.Tonewise they done sound as good as my Magnepans, but they can be very listenable. They seem to shake off inter-aural crosstalk and display a certain headphone kind of separation.
As for a sweet spot, it seem to be there the minute you walk in to the room where the DML's are playing.
Still, very interesting!
Hello everyone,
So after I saw the Youtube video by Tech Ingredients on these DMLs a couple of weeks ago I was instantly intrigued. Since then i ordered two Visaton ex60s for first experiments and started to build some XPS panals.
I already experienced some of the properties these panels have. The LF for example get much stronger when using 30mm thick material compared to 20mm XPS, also overall volume is really dependent on panal size. All of that is probably nothing new to you but never the less fascinating to experience in person.
Now to my questions: Has anyone of you tried the method described in the video, where weights are placed to dampen some of the resonances? I see Bertagni has implemented something similar... I guess.
What thicknes of endgrain Balsa would be appropriate? In some other forum a person chose 3mm and said that thicker panals would make it sound slow/mushi? but in the video ist seems to be about 1/2". This material should also be interesting for a cfk laminate I can imagine (good dampening of the cfk resonaces) ? Kind of like tectonics panels.
After my order was already placed I read that the Visaton do not produce the best sound quality (still very impressed by the result),so for later builds I would chose a different one. Any suggestions? Is the Dayton Ultra still the one with the best "Hifi" potential or are there others that don't break that often?
I am really looking forward to your replies! In the meantime I will start reading on this paper which seems to be very informative: https://urresearch.rochester.edu/fileDownloadForInstitutionalItem.action?itemId=32717&itemFileId=182509 Do you know it?
Hi everyone,
I hope it's OK to post here even if it's been a while. I've already spent 2 hours reading this topic (still not finished). So interesting, thanks for sharing, everybody, especially Bendingwave :thumb:
I'm a newbie, but I would love to get hooked into building speakers and co. I love DIY, and building expensive stuff for cheaper :P
And this NXT thing looks so promising.
For my first try, I want to build a very simple system with 2 panels that will be also decorative. It could be very cool to have music in the room, but without any visible speaker!
So I will buy high-density styrofoam, stick an art print on it, and hang it on the wall. Do you think it's a good idea?
I won't be able to round the corners, but I don't need the perfect sound, I just want it to sound better than the Amazon Echo in this room (should be easy to beat ;-). I've read this tuto: http://projectgallery.parts-express.com/speaker-projects/dml-flat-pannel/
I bought 2 exciters model TEAX25C10-8 (because I live in Spain, and it was not easy to get the Dayton). Bendingwave, I've read that you also bought them for testing. What do you think of them? Is it good enough? How is it compare to the DAEX25FHE-4 for example? Because I already tried them on various surface (but without sticking it because I'm waiting for the styrofoam to arrive) and the sound is horrible for now :? I hope it's normal.
I also plan to buy a subwoofer and integrate it into a furniture.
Thanks in advance for your feedback on my first project. Suggestions are more than welcome
Hello all.
While I may be new to this forum, I believe some of you knew by father Zygadr (Rob Zygadlo) who I understand many of you discussed what I think was coined the Z panel Styrofoam speaker.
After reading through his previous posts, I am very curious about something my father spoke so passionately about.
I think, I may want to pursue making my own set or preferably buying a pair from one of you folk as a lasting memory to my dad.
If any of you can help me out with step by step instructions and material breakdown or rather can build and sell me a pair, please get back to me.
Many thanks
Regarding the frame I recommend the paper 'The effect of boundary conditions and ribs on the total radiation efficiency of submerged plates': https://eprints.soton.ac.uk/369232/1/Eprints.pdf (https://eprints.soton.ac.uk/369232/1/Eprints.pdf)
While the real behavior of a free floating panel is not as bad as the paper suggests, it becomes clear that a frame is the better choice. As a simply supported suspension is harder to get right I went for the completely clamped version and just glued the frame on the plate.
I am not sure if a spline improves the sound in all cases. It should help if the magnet is not massive enough to handle the deeper frequencies. But I think in my case the stiffness of the plate prevents the deep bass part.
But independent of the sound quality I think it is a good idea to support the mass of the magnet of this heavy exciter.
In respect to the tweeter I am with you. For the high frequencies the location of the exciter should not be critical and as the lower frequencies have lesser amplitude in the corners they are a good place to reduce bad interaction with the (little) mass of the tweeter.
This is Yamahas version of DML/BMR loudspeakers which uses a DML/BMR driver for the bass while combining a conventional cone type drivers for the mids and highs.
https://www.youtube.com/watch?v=XNGsFul8sXI&t=172s
Here's some historical info on the yamaha ns20. https://europe.yamaha.com/en/products/contents/audio_visual/hifi_components/hifi-history/speaker/index.html
If you look at all the professional manufacturers of DML/BMR loudspeakers from Bertagnis, Sony's APM's, Technics SB flat driver series, Yamahas Ear speakers to Podiums you will notice they ALL use some sort of frame and spline....There is a reason why all of these professional loudspeaker manufacturers utilize a frame and spline.
The spline is needed to support the magnet on higher excursions as it needs something to push against....with nothing to push against to support the magnet on higher excursions the magnet will rattle and make a lot of noise and also some percentage of energy will be lost resulting in lesser/weaker vibrations going all into the panel....not sure if that made sense but oh well. LOL
Thanks for the historical article Odal3.
Someone on Audiokarma said that Yamaha licensed the technology from Bertagni/BES....which is probably why its shaped that way like an ear. If you look at bertagnis design its shaped very similar.
https://img.usaudiomart.com/uploads/large/1096124-bertagni-electroacoustic-systems-bes-sm100-speakers.jpg
Paper honeycomb does NOT vibrate like foam as that is one of the main reasons why EPS is my choice of panel material as well as XRK's foam speaker enclosures.So you suggest to use the same material for enclosure as for the panel?
When EPS/XPS foam is used as an enclosure (or DML panel) it vibrates like a instrument especially in the lower frequencies......I made a DML panel sub using T.E. frog exciter (incorporating XRK's foam enclosure) and compared it against the conventional cone type of subwoofer (polk psw10) using the same sub amp and my DML sub sounds better with better detail, accuracy and it actually plays deeper/lower....The only thing the polk psw10 did better was it hit harder with more punch due to the conventional pistonic movements of conventional cone type of drivers. Sure the polk sub is a entry level sub at only $100.00 but my DML sub cost me only $35.00 to build.A DML sub is interesting! Do you have any pictures to share? Which dimensions do you use and how deep does it go?
Also a DML sub blends better with DML panels then with a conventional cone type of sub.
Like I've always assumed that a single exciter per panel is the best way to go for the most accurate of sound.....with that said my next project is to make a 2 way with two separate panels utilizing 1 exciter per panel instead of 2 exciters on one panel....I second this. The panel I built sounds horrible when increasing the volume. The tweeter produces strong resonance distortions at ~470 Hz. Seems like the shaking of the panel is to much for it. I think I try to add a stick of wood diagonal at the corner to separate the tweeter part. Inspired by the bertagni speakers. ;)
I wish there was a way to let you all hear them I bet yawl be blown away and even more so when you realize it cost almost nothing to build them. LOLThat is the negative part of this hobby. You can capture an image of your speaker and show it to the world but you cannot let the world hear it. The only chance is to document your journey to encourage people to try it themselves.
One way to decrease tweeter resonance is to use a non polarized electrolytic capacitor (4uf) at around 5khz.As mentioned I build a crossover. The takeover is at 6 kHz. But it is not an electrical but a mechanical problem. The movement of the panel introduced by the bigger exciter is to heavy for the tweeter. This is happening the same way when I disconnect the tweeter.
Tip/one of my techniques...........DML panels have a very very wide (dispersion) soundstage in which it can sound very diffused or unrealistic....to control dispersion one can use the "FRAME", as sort of like a guide to control and focus the sound so it sounds more foward and prominent....Depending on the depth of your frame, instead of aligning the panel to the front edge of the frame move the panel 1/4inch into the frame so there is a 1/4 inch lip that will act as a guide to focus the sound....The further back the panel is moved the more focused the sound becomes.Good tip, thanks. At the moment the wide dispersion is a thing I like about the panels. You can walk the room with very small changes in frequency response. I plan to use some outcomes of my experiments for background music in some rooms. In this case the diffuse, backgroundish sound of the panel matches perfectly. :)
Hi everyone. Well like two months ago I got hocked with DML's. I can't really tell where I saw the first sample, but I ordered 10 exciters from China 40W versions of Dayton's. I couldn't order from the US because of tariffs :lol: I think I got the same ones from billionsound. Because everyone here said that EPS/XPS would be best I tried them first. When I tried some Birch Ply I threw away the plastics. They really sound unnatural and plasticy?? Wood gave me more pleasure. The best results I got from 3mm (1/8th inch). My panels are 60cmx120cm (around 2 by 4). As the last few messages suggested I've put a frame around the panel. They are hanging from the ceiling for now but a proper outer frame is in the planning. Yesterday I got some Spruce Ply as well. It's not the highest quality spruce and it's not framed from behind yet, but the first tests are amazing. Again 3mm (1/8th inch thick). Tomorrow I will also try to paint one panel with white epoxy paint. I want to copy the process of Goebels High-End speakers. They are using a wooden panel (small one like B4 paper size) and cover that one completely with fiberglass and epoxy (at last it seems like that in one of their videos and it says so in the patent documents). If it works better than plain wood I can take the panel to a UV print shop and have a photo on the white epoxy printed. Spruce panel was 125 cm x 250 cm in size (50x100 inches) and cost 21 Dollars. So worth a try I would say.
Hi everyone, what china exciter model, please?
Because everyone here said that EPS/XPS would be best I tried them first. When I tried some Birch Ply I threw away the plastics. They really sound unnatural and plasticy??
You prepared your 'plastic' panels as suggested by sanding of the skin and replacing it with PVC? After this my panels didn't sound unnatural anymore.
you mean vinyl glue?Typical you use white glue. But there are pva-based craft glues that should work just as good. Mix it with the same amount of water and glue and use a foam roller to apply it to the panels. You can use a hair dryer to help drying.
In my opinion, DML/Bending wave technology is like throwing a pebble in a pond and watching the ripples flow to the edges....Bigger the pond the longer it takes for the ripples to reach the edge, the longer the bass travels the muddier/sluggish it will get if the panels are too big because it will take that much longer for the bass to travel and reach the edge before stopping.
I see this 10 kHz falloff on all my XPS 2cm panels. Seems to be material specific. The bended panel I am working on uses XPS with 5mm thickness. First tests by just holding an exciter against it suggest that they may play up to 20 kHz without falloff.
I think you misunderstood what I wrote as I didn't mention anything about the speed of the frequencies and or the thicknesses......What I did mention was the "SIZE" of the panel and that on a bigger/larger panel the vibrations will take longer to reach the edges then a smaller panel....For example a 12inchX12inch panel the vibrations will reach the edges before a 24inchX24inch panel as it takes longer to reach the edges of a bigger panel....The longer the vibrations have to travel without stopping on a dime means it will be muddier and or sluggish....its a fact that the ripples in a smaller pond will reach the edge of the pond before the ripples of a much larger/bigger pond which goes the same for vibrations.
I also dont buy into that theory of thinner panels equals slower bass and or that it should not matter if you make the panel bigger or thinner to fit lower waves (unless its so thin that it can bend more then a quarter of the way)...
c = M*sqrt(2*pi*f*h)
c = speed of wave
f = frequency
h = thickness of panel
M = material constantof course there are limits to how big, thick or thin a panel becomes before certain factors occur.
Thinner panels produce more output/spl then thicker panels in all frequncies but it doesnt mean its always better as too much or too little of anything is not good...it needs to be just right. :wink:
c = sqrt(2 * pi * f * h * sqrt(E / 12 / (1 - u^2) / p))
c: speed of bending wave
f: frequency
h: panel thickness
E: Young's modulus (material constant)
u: poisson ratio (material constant)
p: plate density (material constant)
As you can see the speed of the bending waves depends on some constants, the frequency and the panel thickness.f_low = pi / 2 * h * sqrt(E / (1 - u^2) / p / 12 * (1.506^4 * (1 / x^4 + 1 / y^4) + 2 * (1 / x / y)^2 * 1.248^2))
f_low: lowest resonating frequency
x: panel width
y: panel height
To get this formular you have to dive deep into Vibration of plates (http://www.dtic.mil/docs/citations/ADA307623).f_high = pi / 2 / h * sqrt(E / 12 / (1 - u^2) / p)
p = 40 kg / m^3
u = 0.2
E = 12000000 Pa
I will admit I don't understand those formulas but I do know that a DML panels size (including thickness) and density plays a big part and I know how to utilize it in my design.The formulas give tendencies that can help. But there is so much more you need to get a feeling for. Think of our surface preparation. Or what you said about using the frame to focus sound. This are important things that are not described by the formulas I know of.
I have read that article before, the funny part is that with all his technical knowledge he didn't make a DML panel to his satisfaction as this is what he states>In short, DML still has a "long way to go" to be as satisfiable as the conventional electro-magnetic loudspeaker in practice.
What are these tendencies that help?The formulas do what they do. They allow to calculate constraints. That can help to chose the right dimensions.
Like I said before all those formulas did not help to increase the sound quality of his panels....those formulas are more of a explanation of how bending waves work on certain panel materials but it wont actually tell you how to make your panels sound better.I agree partly. You will not build the best sounding panel by just looking at formulas. You need experience for this. But you can get some experience by understanding formulas.
One cant get experience by understanding formulas. :roll:...What you can get is a (not always) better insight when designing your panels......Ok, we differ in what we call experience. I would totally call it a kind of experience if you understand a simplified model of the reality described by formulas. Let us agree that we disagree here and focus on the things that matter :)
This insight can also be achieved by actual hands on experience/experimentation.Correct!
Those formulas are just basic beginner understanding of bending waves on how they react on certain materials like what type of material to use , what size , what thickness , what density which is the basic questions that every one asks when getting into DML panels....other then that it has no bearing on how to increase the sound quality of ones panels, which was basically my whole point from my first response to you regarding the formulas.I think the basics are very important. And you can save some time with experimenting if you don't need to work this things out yourself.
What made you choose to use elastic bands to suspend your panels while the bottom edges are sitting on cosmetic triangle sponges???
If you liked the sound of your Mission X-space nxt panels why not try to mimic the designs of those panels first?
(https://www.audiocircle.com/image.php?id=186908)
i hope to be clear, red is the 45X50x1 cm EPS panel, in violet the 90X50X1 cm EPS panel.
the violet is my favourite
And this is measurement of Russian speaker:
(https://www.audiocircle.com/image.php?id=184564)
Impressive!
I would of used 2 part (5min.) epoxy adhesive instead of PVA glue....Even the type of adhesive can affect the sound.
Annoying sound from the rear of the panels is due to the vents in that particular type of exciter...I prefer the exciters without vents.
Tinny is mostly due to the type of material in your case XPS, which is the reason I prefer EPS for its warmer less tinny sound.
One way to provide more focus is to use a frame for a more foward directional sound.
When using a frame you must use some type of weather strip foam or rubber to attach the panel to the frame so that there wont be any distortion from two solid objects touching each other....I use frost king brand available at Home Depot.
Not sure about how long for a exciter to break in but a brand new exciter is stiffer then one that has been used a while.
Here you can hear how it sounds in the recording
https://youtu.be/j5ww2Fgd9D8
https://youtu.be/2aXVxbXcS3w
Thanks for your input , much appreciated . I suspect that tinniness can be tamed , it's definitely the rear side combining with the front . I don't have many options for placement such as pulling the panels out from the walls so I've placed some open cell foam on the frame behind the driver , then draped some long haired wool over that which was better . I have a few sheets of Rockwool RWA45 , I'll cut out a piece , wrap it around (then clamp to the frame) and give that a try
In terms of closed back exciters , what would you recommend ? Are the smaller sub 20w Tectonic Elements drivers worth looking into ? Much easier for me to obtain in the UK...
cheers
Nic
It sounds good....What is the panel material they are using, Antinox?
honeycomb paper. There are some more records from Russia:
https://youtu.be/7gAYd6sdox0
https://youtu.be/VPew6zviYhY
Hey everyone, been following this thread for a while, decided to have a go, I made some panels with 30mm XPS foam, 600mmX970mm, sanded, treated with 2 coats of 50/50 PVA/water, suspended by a small nail in each top corner from fishing line, using DAEX30HESF-4 at golden ratio. I was really looking forward to enjoying these panels but I'm finding them very bright, pitchy and thin to listen to, even with the support of a sub they don't seem to have enough body, is there anything I can do to improve them in the midrange without EQ? I don't have an EQ or RTA so I can't measure them, but I would really like a bit more depth from them.
XPS material can sound a bit bright that is why I use High Density EPS for its warmer tones...30mm is a little too thick, try 10mm....Pitchy and thin is most likely due to your design of hanging them from a fishing line. (not sure where you got that idea from, Tech ingredients video?).
If you want more depth from them then you will need to change your design and make them "Floor Standers" which utilizes a frame to hold the diaphram material in place and a spline to hold the exciter in place.
It would look something similar like this> i88.servimg.com/u/f88/13/48/14/85/img_0337.jpg
What makes you say they are real NXT speakers? There have been many other drivers/speakers designed along similar lines over the last 35 years at least, to my knowledge.
Hi guys!
I'm new to this type of drivers and I am not sure about the mounting holes fitting.
For example the
http://www.daytonaudio.com/index.php/daex30hesf-4-high-efficiency-steered-flux-exciter.html
DAEX30HESF-4
To my mind, the driver's mounting holes would be fitted to an independent fixing point, not to the board that is supposed to vibrate, so that the mass of the driver is fixed and immobile, and thus "resting" and be able to push more of the energy into the vibrating board.
But I can't find anything detailing how these holes are meant to be used.
Thanks!
7. From what I hear in my listening room, the sound of a DML is so far superior to other...
Rob.
Nice panel congratulations, maybe you can pass pro-audio bass shakers they was not good in tone definition when I had listened a few years ago (1990s).Thank you. I bought Dayton Audio mini puck bass shakers. I want to test those potential.
@Miiksu Nice work on your panel, and especially for getting it for no money :D ! Filling the room with music is a good way to put it, I love that it's a completely different listening experience to normal speakers! Have you built a frame for you panel of interest? From posts I've read here Bendingwave swears by them!No frame. Bare panel with dampering material clued to the back. Not sure about that bendingwaves. I think its because its bare sandwitched aluminium panel and soundwaves coming every direction but only the backside is dampered. On my measuring 5 kHz is slightly recressed and upper treble has some unevenness too. It was measured on listening spot, approx 2 meters of the speakers. Composite panel is cheap stuff but u have to buy it large quantities.
Hey folks, I’m Duane and I just registered here, this being my first post.Welcome MisterD.
Without reading all through this thread, I hope you don’t mind me asking:
How many of you have tried using two exciters per panel - directly opposite from each other - one on each side of the panel, and wiring them so that while one “pushes”, the other “pulls”? What might they sound like set up that way?
Asking ‘cause that’s what I have in mind. I recently bought several Dayton “Thrusters” and a few pieces of 2’x2’ Foamular to play with. Ready to start shaping..
Have you guys seen these speakers by techtonic
https://www.tectonicaudiolabs.com/professional-audio/dml-speakers/
Looks like they use a thin piece of aluminum for their DML panels
How many of you have tried using two exciters per panel - directly opposite from each other - one on each side of the panel, and wiring them so that while one “pushes”, the other “pulls”? What might they sound like set up that way?
I have in my pocession, two DIY, 79''tall by 28 inch wide by 1/4 inch thick prototype NXT panel speakers.
They will soon have a seventh NXT ''exciter'' mounted to the rear of each panel(all in a vertical array, evenly spaced but no one exciter in the exact middle of the panel). Impedance : 4.67ohms.
Due to 7 exciters per panel, I estimate a sensitivity of 95db, maybe a bit more.
For those who are interested, I have followed the design of PODIUM LOUDSPEAKERS in the U.K. :thumb: BUT, ........mine are somewhat larger with more exciters per panel than their biggest model(Model1 : 5 exciters per panel).
I have posted on this forum as it is the closest thing that relates to this type of speaker ( sort of).
The panels are made from GATORFOAM which is a polystyrene core sandwiched between a very thin wood fibre composite material known as LUXCELL (a kind of wood veneer ).
The exciters create a DML (DISTRIBUTED MODE LOUDSPEAKER) speaker which is essentially a large surface made to vibrate with random modal excitations.
I am stunned at how good these things sound but it's been a long hard road finding the right panel material and positioning the exciters to obtain optimum fidelity.
They can produce immense bass at times(but not sub woofer like) and have a transparency, speed and midrange resolution to die for.
They still need mounting in frames (no time lately :duh:) so they rest vertically up against the edge(with a piece of spongy foam) of my horn speakers at the moment
I can post some pics. if anyone is interested?
Can you give us exact dimensions and positions of the Exciters? And what kind of exciters?Sorry to inform Zygadr passed away in 2015.
Not visited the thread for quite a while so just catching up......
Unless the exciter design is very poor, a DML's HF extension is determined by the panel material's compressive strength and internal damping properties, not the exciter performance. Aluminium honeycomb panels are excellent and Nomex honeycombs are also a good compromise for high comp strength and low panel mass. The low panel mass of, paper skinned, aluminium honeycomb panels gives 93/94dB @1W sensitivity when used with a decent exciter. Aluminium honeycombs with high quality skins give flat HF extension to 25kHz and decent output above 30kHz.
DML panels have to be VERY big to make bass flat bass below 150Hz. Panels are packed with modes at higher frequencies but there are only 3 fundamental modes at low frequencies ( length, width and the lowest diagonal mode ). Panels are sparsely modal at LF and densely modal at HF.......consequently LF performance is seriously lumpy.
When developing a DML, try measuring the off axis polar response and at multiple different mic distances too; DMLs are strange things and don't behave anything like conventional moving coils. DMLs are simultaneously in phase and out of phase with themselves at the same time!! Small changes in mic position can have a huge effect on measured performance.
Typical you use white glue. But there are pva-based craft glues that should work just as good. Mix it with the same amount of water and glue and use a foam roller to apply it to the panels. You can use a hair dryer to help drying.
There are different suggestions how many times you should treat the panel for best sound. Most treat once or twice. Someone suggested to treat the side with the exciter twice and the other side once.
After this the panel feels a bit like sand paper.
My first test with XPS panels but then I discovered painting canvas and I am amazed how full these sound. Ill post some pics soon as I am tweaking and testing them a bit this week to see what I need to do but first test on the canvas was amazing full spectrum, just a few spikes.
Life is short (shorter for some of us). So reading through 161 pages looking for the tidbits begs the question ... is there a webpage that provides the pertinent details to build a very nice sounding panel?
I've seen Tech Ingredients YouTube videos and have read other pages but I'm still looking for a more definitive project. I've Googled and have so many tabs open I need a wider monitor but I'm not finding what I'm looking for. Basically I'm looking for success first and then I'll delve into experimenting ... and experimenting seems to be the focus of many tabs.
In the DIY community majority of those into DML are still in the experimental stages and even those that have been experimenting for a long time still have not found a satisfying good sounding dml panel.
Thanks to all above for the input.
I was hoping that somewhere (that I have yet to find) was a distillation of what has been learned via the experimentation. I'm not against experimenting but was hoping to build on the current knowledge base and avoid the wrong terms. Depending on Santa, I may be starting in January.
Hi all, first post but I've been stalking this thread for a while. I finally got my first test panel cut a few minutes ago. It's a small 250mmX404.5mm 25mm XPS panel, gonna start sanding now and apply the pva/water mixture and then start cutting another design.Nice panels. Can you please give us more info. How did you cut them? How do. they sound?
(https://www.audiocircle.com/image.php?id=200768)
Hey guys,
about 3 years ago I assembled my DML speakers with Dayton exciters and very stiff Styropor plates. Together with a Subwoofer they work very well.
Now my problem is that one of the exciters fell down (I guess the adhesive gave up) and I'm looking for an adhesive (tape) to glue them back. Everywhere I look for it says "3M VHB", but there are tons of different 3M VHB tapes. Does anyone know which tape exactly is used?
Good news from the exhibition, DML speakers showed a high level of this technologyGreat sound quality in this video, camera dont move, seems another speaker IMO. Small NXT panels dont have this huge kind of bass or hi SPL.
https://youtu.be/honDkrXIS8c?si=GsG3R6lH1i3I36a_