[Bendingwave]

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 
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

Steve, First off you seem to make it sound like I am forcing others to follow my design or telling others that they HAVE to cover the vents, I said one can cover the vents and (experiment) see if they like the change in sound because vents do change the sound..I dont have to put up a disclaimer and (warn anyone) baby sit everyone and say covering vents will reduce power handling due to voice coil over heating faster...its like one saying well you didnt tell me I couldnt use a 3 watt exciter with my 500 watt rms amp at high volume levels  .. I must point out that there are a lot of exciters without rear vents and I never had a problem with exciters without vents even driving them as hard as the one with vents you just have to have common sense to know each and every single exciters LIMITATIONS including when covering some of the vents....Everyone should know what a vent is as that is common sense knowledge that vents mean higher power handling due to not over heating the voice coil but it will depend on many other factors like how much amp power/watts and or at what volume levels and for how long a period of time....If you read carefully what I suggested I said one CAN COVER UP SOME OF THE VENTS LIKE EVERY OTHER VENT meaning there is still some vents open, I NEVER SAID cover up all the vents..........I have never had any exciter melt a panel, nor one die on me by over heating (even with every other vent closed) even at fairly decent high volume levels for prolong periods of time say 3 full albums length of time from my 100 watt Yamaha receiver.... and I do have over 70 exciters.

There is a difference in sound between a vented exciter and one without vents and when closing some vents the sound changes. Maybe your ears cant hear it but mine can. Even others stated they can hear a difference in sound from exciters with vents as that is the reason why some people use the back side of the panel were the exciters reside as the fronts because the vents change the sound and some people prefer the sound coming out of the vents.

Once again utilizing Bertagnis design one can use 2 exciters with very little combing effects while having a good full range sounding panel. You wouldnt know this because you have never heard one in person.

I have never heard a NXT panel in person (have YOU?) that is why I cant really comment on the sound of NXT panels BUT I do know exactly how Bertagni speakers sound like and they sound really good when set up right....Now if I have heard a NXT panel in person then I would compare them and tell you which one I prefer better and if the NXT panel sounded better I would try and mimic the NXT panel for my design...Until then I will stick with what worked best for me which is mimicking Bertagni's design....and you can stick with what works best for you be it free floating panels.

I just finished painting my new pair of panels today and tomorrow I will start working on the frames/spine.

Oh I forgot to address you on the spine mounting thing....Like I said in my other post I dont have any measuring tools except for my ears...maybe your panels rolled off fast at 40hz but NOT all panel designs are the same....What Ive experienced without a spine the bass seems to be little more pronounced and even a tad bit deeper but with a Spine the bass becomes more accurate including the mid and high frequencies as well..I prefer ACCURACY over a tad bit of lower extension in bass....This is most likely the reason most manufacturers of exciter technology speakers utilize this method of using a spine like Bertagni, Podiums 0.5s, BMR , Sony APM.....Zygadr said he heard the Podiums so his goal was to mimic the Podiums. Some one else said he heard the Podiums 0.5 and the Quad ESL 280's and he preferred the Podiums.

[OZZIOZZI]

Sedge, I agree about the cooling effect of the holes around the magnet and through the pole piece. Once the exciter is mounted on the panel the small cavity formed would definitely pump air through the magnet. the ones around the magnet pump air from the surround. I guess both work to cool down the coil on my DAEX25FHE-4 4ohm 25W.

I cant speak as an expert, but I have read that the exciter blocks some of the high frequencies to the rear of the panel from about 4kHz upwards, not completely, but gradually reduces the high frequencies. That could account  for the difference from front to back sound.

Just my 2cents worth.

Ozziozzi

[sedge]

Ozziozzi
Yes Ozzi you are correct about the exciter being the biggest problem when it comes to rear radiation ,a small 25mm exciter beams from the coil area,obviously if you have the exciter with magnet and suspension blocking the sound radiating to the rear this will effect the sound .
When I first heard the podiums ,I thought the sound was more lively from the back than the front,but when I tried to mount my exciters on the front of my poly panels ,at first they sounded improved,but after a short time it became obvious that it had a fazed sound,from the reflections from the magnet and the spider,which is also vibrating .
Luckily low powered exciters are quite small,now you can see the problem with using high power exciters with large magnets 3 to 4 inches  in width ,plus the mounting frames of course.
It's best to keep it as free and open at the back as possible.
That is why I am more than happy with my 10watt exciters on a poly panel.
Steve

[sedge]

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

[Bendingwave]

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

Steve, you chose to take the PETTY ROUTE as if you have a grudge or problem against me nit picking at every little thing I say talk about ego and pride  .  You sound like my wife or mother, telling me what I SHOULD and shouldnt do.  ....Its like me telling you that you should do this and you should do that like a female on her rags. 

So now I am responsible for what everyone else does with there exciters????? ...if one makes a suggestion and they screw it up due to not knowing there own products LIMITATIONS is it the person fault for suggesting it?????....like that example I gave of one not knowing a 500 watt rms amp driving a 3 watt exciter at high volumes will destroy that exciter ..Once again I am not FORCING one to follow any of my advice...Every one knows that a vent is used for some type of COOLING and those that dont know even the basics shouldnt be diving in to speaker building blindly...If a person did not know what the meaning of the word VENT is in a driver then they would of asked me what is a vent and then I would of explained it to them....You make it like its my duty,job or responsibility to inform people of every little detail even the common sense obvious ones and then try to make it seem like its my fault if anything goes wrong (even though NOTHING has gone wrong).....Some exciters have NONE, ZERO, NADA VENTS like some of the COIN TYPE EXCITERS like this one> https://www.parts-express.com/dayton-audio-daex25ct-4-coin-type-25mm-exciter-10w-4-ohm--295-220  ....You make it sound like I did something terrible wrong when in reality I did NOT do anything wrong, it just seems you are JEALOUS of my advice and therefore try to nit pick and find any PETTY shit to try and discredit me. I see straight through your bullshit tactic.

So if someone uses lower power exciters and stretch them to there limits and because they dont know there own exciters LIMITATIONS (even when covering some/ever other vent) that is my fault???? LMAO....boy you are PATHETIC. 

I can explain Bertagnis methods but its not worth my time for someone like you.

That didnt answer my question which was >Have you heard NXT panels in person?

So what if Zaygdr changed his mind, it does not change the quality of the podiums sound when he first heard them in person which probably inspired him into building his own and experience exciter technology....and also there was another person that said he preferred the podiums over quads, which just goes to show you the quality of sound when utilizing a spine/brace or else they wouldnt use a brace if it did not help improve the sound at all, instead they would of left it free floating but that is not the case.

[sedge]

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

[Bendingwave]

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

Pssshhhh if you aint start none there wont be none son as everyone with half a brain can see through your bullshit tactics. Thats the only shit you could say because you know for a fact that everything that I said is true.

You must be one them SJW's I hear so much about that cant take what they dish out.  Probably all crying and whining when Trump became pres. 

I didnt come here for some petty bickering crap.....I came here to share my experiences of my panel designs that I have perfected to my satisfaction. Hoping it will inspire others into exciter technology.   

Cant we all just get along?

[OZZIOZZI]

I noticed with some of the higher powered exciters that they have a horn or waveguide as part of the cooling vent.



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


Ozziozzi

[Odal3]

Please no personal attacks. We have had this thread going for so many years so I would hate to see it heading to the intergalactic wastebin.

[Bendingwave]

Ah yea I recall even Zygadr stopped posting for while due to personal attacks most likely from a jealous person. 

Lets get back on track, this is where I get my EPS from if anyone is interested.

http://www.ebay.co.uk/itm/EXPANDED-POLYSTYRENE-SHEETS-FOAM-PACKING-VARIOUS-THICKNESS-AND-GRADES/201604023608?_trksid=p2047675.c100011.m1850&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20140107083358%26meid%3D955371309a124fbaa587e739dbc51540%26pid%3D100011%26rk%3D1%26rkt%3D6%26mehot%3Dpp%26sd%3D200991844997

I recommend the UHD, EHD and HD grades in that order as the higher density grades are more accurate sounding...stay away from the LD and SD grades as they sound muddy.

[Bendingwave]

I noticed with some of the higher powered exciters that they have a horn or waveguide as part of the cooling vent.



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


Ozziozzi

That is basically how I mount the exciters with the mounting screws.....I drill a hole in the spine that fits the exciter and screw the mounting holes to the spine just like a conventional cone driver so the vents can breath and fire the sound back wards as well just like bertagni speakers.....This is the reason I said one can change the sound when covering some of the vents.

Exciters with multiple vents have a more diffused sound because sound is radiating through the back vents....exciters with NO vents or ones with a single vent in the middle of the magnet have a more tighter accurate sound.

Thats why I said (before I got into a pissing contest with sedge ) one can experiment and cover ups some of the vents to see what sound you prefer that suits your own tastes.

The DAEX25FHE exciter has many small vent holes in the back you can try experimenting by covering up every other hole to see how you like the sound and do a direct comparison with the other exciter with no vents covered....you can use any type of tape to cover the vent holes.

[Bendingwave]

Another type of Bertagni speakers> https://www.youtube.com/watch?v=vcbXmdMGwqk&t=115s

The down side is he recorded the speakers stacked up too close to the ceilings so they sound too bright with less bass....If he demoed them while on the floor sound would of been better.

I also just bought the Dayton Audio DAEX25W-8 exciter to try it out as it seemed to be the only exciter where it had a higher out put in the high frequencies then the mid bass to mid range frequencies.

https://www.parts-express.com/pedocs/specs/295-232--dayton-audio-daex25w-8-specifications.pdf

This exciter should make a good tweeter/high frequency driver to increase the high end extension.

[Bendingwave]

Here's the pics I promised months ago.










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.

Now this is similar to how I use a frame and a spine holding the exciter....bumping it up to show others the idea of how to mount using a frame and spine....great pics by Irishpatrick33.....on page 69.

[OZZIOZZI]

Irishpatricks pics show what I have in mind although I am thinking more rectangular ( odd ratio like 13 X 25)  rather than square. Interesting high freq exciter you found, but I think I will stick with the small NXT panels I have for tweeter range.

I thought people might be interested in this cartridge glue I found at my local Aldi store. It is especially formulated for expanded polystyrene and wood. So ideal for attaching XPS to various surrounds. $3.99 per 450gram tube and it should go a long way, especially if you use a thin bead or spread it with a bit of wood or plastic. Up to now I have been using water-based contact cement or PVA wood glue to stick XPS to other things. The cartridge should also make application easy. BTW it says on the label that you can sand it and paint over it when it dries. You can prime a surface with 2/3 adhesive : 1/3 water to increase bond strength, while Immediate bond strength is 130kg/sq meter.

Ozziozzi

[Bendingwave]

Hey OZZ, I am curious to know how your rectangular panel sounds like are you using them vertically or horizontally? I havent tried that brand or type of adhesive yet, I wonder how the sound will differ from pva wood glue?

I remember Zagydr saying that every little thing can change the sound of the panel in which I agree with him as even the type of adhesive used to attach the exciter on to a panel can change there sound.....even Bertagni uses this method to control certain frequency responses.

[TexBear]

Hello folks -
I've been reading (and re-reading) this circle for a few months now. I'm having some fun with 2'x4'x2" thick Owens Corning Foamular 250 XPS panels since last December. On the first try, I mounted a single DAEX30HESF-4 exciter to the dead center of each (3M VHB 2# double-sided tape interposed between exciter and panel), running them with a SMSL Q5 Pro class D amplifier. Incredible! Great detail, and bass response made them walk on their own. So I set them on some 1/4" thick silicone hot-pads, which stabilized them some, improved the sound - but they still walked around a bit.

I later added a second exciter to each panel and reconfigured positions a' la Monacor specs. I also switched to a 60 WPC ADCOM stereo amp.
I've noticed a loss of "open-ness" and also a sort of plastic harshness. I can correct with EQ (either windows 10 EQ, an AudioControl OCTAVE outboard EQ, and an audio EQ app for Chrome), but not with all program material. I haven't sanded them, coated them, or rounded the corners on this first experimental pair. I notice that all the 8'x4'x2" XPS sheets on sale at Home Depot have a pre-cut slit that must be for easy cutting to fit 16" on-center wall studding. I'm sure this must influence the propagation of sound waves, at least across the top 1/4" panel surface - so not sure how to overcome that, short of trying to fill the slits with some sort of XPS-like material. Perhaps I'll try that.

Natural sounds and instruments sound great, in jazz, pop, classical genres. Symphonic content seems to be highly subjective in how they're engineered. Much more variance in sound quality than I note with other genres. But that was true even with cone drivers. Just seems much more noticeable listening to these panels.

I really just wanted to thank you all for your generosity in sharing your experience. It's saved me a lot of time, and has provided hours of great listening experiences. I'm having way too much fun with this!

[Bendingwave]

Hey TexBear welcome to the DML thread, one of the longest and somewhat confusing thread on this site.

Using more then one exciter especially close together seems to interfere with each others waves and could have some cancellation effects...that is why I dont use the la monicore specs placements of the exciters........instead I use Bertagni's method with one exciter in the middle used full range and one exciter in the corner with a Capacitor used as a tweeter to increase the high frequency response.

Ah the scorned pre cut XPS must be the "BLUE" colored one right?....I tried it and when compared with EPS, I preferred the sound of the EPS over the XPS.

Since these panels retrieve so much detail, there sound quality is depended a lot on the quality of the recorded material, as the better the recording the better the panels sound and on very awful recordings the panels just sound awful since its portraying a lot of detail even though those detail they are retreiving are unpleasant.

[TexBear]

Howdy Bendingwave -
The XPS I picked up originally to insulate my old cellar door. It's pink and has the image of the "pink panther" on it. I've not seen any polystyrene 'round these parts that's colored blue. At least not yet, and I've been looking, as I've read your previous posts regarding EPS and blueboard. I'll keep my eyes peeled.

I've got a couple of 2'x2'x2" panels that I've sanded and rounded the corners, then coated with the recommended PVA/water/ink mixture, and I'm going to try those with a single DAEX30HESF-4 exciter mounted in Monacor position #1.
I imagine that these will sound OK if I use them with a subwoofer.

That's a big 10-4 on the quality of the original recorded material. The listening experience on well-recorded music is just outstanding, and on music that's not recorded well, it's painfully revealing.

Now, I gotta get back to work!

[OZZIOZZI]

Hi bendingwave and others following this thread. I have been off air recently because of illness and computer problems. Even now I have a strange screen issue with Audiocircle. See pic attached.



Makes it difficult to read posts.

Re: glue, what appealed to me is that it is sandable and paintable, which means you should be able to get a good finish even if you are a bit messy with application of glue.

I plan to use panels vertically to fit narrow (16" or 42cm wide) baffle holding a couple of open baffle woofers XO below ~ 200 Hz. This is to remove problems I have had with buzzing panels at lower freqs and to give me a bit more slam for bass and drums below 200hz. I also have it in mind to use an NXT small panel as upper-mid/tweeter as I really like the sound of those apart from the fact that they don't handle bass or even lower mid range at decent volume without buzzes and distortion. They are fine at near range listening levels, but I dont think they will fill a room unless I limit the freq response to upper mid/treble range. I will get back with further results when I have more time and energy.

Re Bertagni speakers and exciter in middle, I suspect that bass panel is working in piston fashion at lowest freqs and transitioning to bending wave mode as freq increases. I have only looked at pics and drawings of Bertagni speakers, but they look to have quite a compliant edge treatment with all those grooves in panel. I think they allow a certain amount of piston movement. Judging by surface area they are probably equivalent to a 15" cone driver. At very low frequencies my 15" drivers hardly move at moderate levels and still drive a lot of air. Am I barking up the wrong tree?

Ozziozzi

[Odal3]

I see the same thing on my end with the difficult to read page format. I believe it happens sometimes when there are some wide pictures posted on the page. Once we get to the next page of posts it will go back to normal again.

Re buzzing panels. If your panels are large enough, you should be able to run them much lower than 200Hz without any buzzing (unless of course you like your music at really loud levels.) The buzzing could be due to a lot of different things but could be a sign that something is not quite right - such as glue is getting loose from the exciter, not stiff enough panels for the volume and type of music you play, how they are hanging/standing, etc.

Try for example holding the panels in the top corners and hold them up in the air hanging loosely - still buzzing?
Before I used a proper glue, I got some buzzing from deep bass and shortly after I noticed the exciters were coming loose. Not saying that any of these are your issues - just wanted to share my experience

However, I agree that you don't really get "slam" with panels and I also complement my panels with OB bass at the low end. I do cross them <100hz since I like the sound of the panel bass but I'm also using wood ply panels too so might (?) vibrate a bit different than EPS. I have played them much lower than that with no issues unless I play "subwoofer test track" type of songs

Hi TexBear! Welcome onboard