[mirekti]

Has anyone tried to combine this technology with OB bass?
For example two 15" AE and a panel on top for everything for above 100-200Hz. I guess if there is no need for LF in the panels they could be much smaller.

Something like http://www.goebel-highend.de/img/home/Home%203%20Slider.jpg but with OB bass instead.
Not sure if this is the panel uses the same technology as those in photo.

...or something like this http://www.diesisaudio.com/en/product/caput-mundi/ but using a panel instead of the horn.

[jmanes]

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.

https://www.youtube.com/watch?v=Qs9Bmri_mqQ

[osssyvan]

Mirekti,

I've been thinking about but had not bothered testing yet. I assume  they would  work great.

-ossi

[jmanes]

Again, an iphone video is certainly not the best way to judge sound quality, but the 16x20 framed panels sound great in the basement media room.


https://www.youtube.com/watch?v=cEAkQSTtxAg

[b_force]

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.

https://www.youtube.com/watch?v=Qs9Bmri_mqQ

That looks extremely neat! 

Can you tell a bit more about the frame itself?
Maybe some pictures from the inside?

[jmanes]

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.

[exspec]

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?

[arachni42]

So, I've been working on my cargo-cover DML sub as time permits. Part of the challenge has been figuring out a way to mount it. There are slots for an actual cargo cover, but of course they are some specialized proprietary shape, and I'm not buying a whole cargo cover just for the little plastic pieces that fit. For the ones toward the front, I ended up making a mold and using Claycrete to make fitting pieces. I made them with a pocket for a 3/4" dowel. I have some speaker carpet Velcro'd to the top and bottom of the panel around the dowel so that it holds it up. For the ones in the rear, well, I haven't figured those out yet, but I really wanted to try it out tonight, so I just propped up the rear side of the panel on a box. I'll take pictures when I've actually figured out a mounting scheme that works.

Anyway, I did try it out a bit tonight, and it was a definite improvement to my system (aftermarket components up front). Now, I can't compare it to a normal car sub, because I've never had one. I've never been after boomy bass that'll wake up the neighborhood, lol, but as I've gotten into audio I've realized how good a balanced system sounds. I'm pretty sure I would not be able to get this panel to shake the house or anything, but I think it will be loud enough. I mean, there's no guarantee I won't burn out these exciters, since my amp can go well beyond their power rating (40W), but we'll see.

This is a 2x4' XPS panel 2 inches thick. (Well, it was 2x8' but I had Home Depot cut it to 2x4'.) I've cut it to fit into my hatchback, so the length ended up being 3-3.5'. I didn't need to cut the 2' side. The thickness was definitely helpful in getting more bass. The panel has two coats of Varathane Triple Thick Polyurethane (a water-based polyurethane). It stiffened it up, which also helps the bass.

I'm using 2 Dayton Audio DAEX30HESF-4 exciters, connected in series. They seem to have more oomph than the others I've tried (the DAEX25TP-4, DAEX25FHE-4, and DAEX32QMB-4). I'm using two to make the panel louder. They're attached with epoxy glue. When the panel is mounted, they are hanging underneath.

When I hooked it up, it blended really well with the front stage. The only thing I could localize to the back was some noise from the panel bumping against the dowel. (This was expected, as I haven't put any buffer in between them to prevent this.) Pretty cool!

I had my LPF set at 100Hz -- I liked it better than lower. But I only played with that for a couple minutes. I haven't played any pink noise or anything; there may be adjustments I make when I really sit down with it.

Here's a picture of the panel. It's definitely rough around the edges (literally), but I plan to cover it with speaker carpet to look nicer.


I might use the other 2-inch thick panel with my indoor setup. I've also modified those panels; the exciters had started peeling off a couple weeks ago. (I had only used the 3M VHB adhesive that came on the exciters.) So I reattached them with epoxy, but before I did that, I decided to coat them. Previously, they had a thin coat of watered-down PVA. Based on some smaller pieces I had experimented with, I gave them one coat of Varathane Triple Thick Polyurethane. The stuff is thick, but becomes dry to the touch a lot faster than the PVA mixture. Still, I left them overnight and glued the exciters on the next day.

It did smooth out the frequency response and make for less EQ. But they could still benefit a lot from a sub of some sort.

Edit: Well, I was playing the panel in the car today, but having the exciters unsupported underneath is a no-go. They fell off!  The epoxy didn't fail; the foam did. So I guess I'll need to make some sort of frame that will help hold them in place.

[jmanes]

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?

There is no lamination or glass over the print, it is bonded directly to the panel. The key is the panel material that I am getting from some friends at Wright Patt. I am using a 2mm panel this time in an 11 x 14 size. This panel is extremely light yet very rigid and I am expecting this thinner version to provide even better high end response and volume. I will add frequency response testing later.




Obviously I don't have an anechoic chamber, my main concern was to get a good high frequency response and we are good out to 19k (and even higher as I had the limit on the frequency sweep set to 19k), which is exactly what I was hoping for with the thinner panel.

[Fidel Costar]

Hi guys (and girls, if any...  ),

I am Fidel Costar (real name Christian), not from Havana - though I love that city - but from Brussels, Belgium. This is my very first message on Audio Circle. English is not my first language, so please be indulgent.

Some people that I trust told me that good DML panels have a kind of magic that no other speaker can touch. So I have been reading this thread from beginning to end and though I learned a lot, I can not say that I am completely convinced.

Come on guys, I do not want to spoil your party, but after so many experiments, so many different panel materials, so many different exciters (many of them shitty built and unreliable), exotic coatings and various magic tricks, it seems to me that not many people are 100% happy (from deep bass to high treble) with their DML panels.

Anyway, I am curious and I intend to build my own DML panels to see (hear) what all the fuss is about. So here is my first question. Some of you recommend rounding the corners and quarter rounding the edges of the panels. All right, but then wouldn't  it be better to try an oval shaped panel? Or maybe a round one?

[pol_bct]

Christo, you're disclosed ! 
have a look at this patent schematics, those ovals shapes are not new

https://worldwide.espacenet.com/publicationDetails/originalDocument?CC=US&NR=2005147274A1&KC=A1&FT=D&ND=&date=20050707&DB=&locale=#

round panel is probably the worst  option, fewer modes than other shapes

POL

[j gale]

POL,  It has been a long time since you posted here. Still using same single panel arrangement? Anything new or changed?    Jim

[pol_bct]

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)



the schematic is drawn in the picture, sorry, the system has reduced the image, I hope you get the cablage




regards, POL

[Fidel Costar]

Hi Pol, 

Me, disclosed? I was not trying to hide. Just used another nickname, that's it... 

Thanks for the patent. I see one of the inventors is Henry Azima. I met his brother Farad at the Festival du Son in Paris, something like 40 years ago !  He then introduced the Mission 770 speakers with polypropylene woofers. In that time, I guess he had no idea of what DML speakers were.

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?  Now somebody is going to ask me to
explain what is an Infraflex... Pol, could you do that for me please?

[pol_bct]

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.

My take is: the bigger surface of radiation, the better it will sound, and rounded corners are the easiest way of scattering internal back waves.
There is also a question of adaptation to air impedance, a small surface cannot have a low acoustic impedance, thus efficiency stay low. (=zero bass). As the surface of radiation increase, say above 1 m², you get full benefits of DML, more modes, more bass, less directivity, better efficiency.

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?  Now somebody is going to ask me to
explain what is an Infraflex... Pol, could you do that for me please?

You could start by cloning Abelma's panels, who are proven to sound good, but with rounded corners if they don't already have, only then, add a sub of your convenience.

I won't try to explain what is an InfraFlex, though it may sound good, it is backed by a very fuzzy theory... LOL

as I previously said:   you can put motor(s) anywhere on a panel, you'll always get some nice sound, but don't name it "Distributed Mode Loudspeaker". I mean central placement and equidistance, as many have done, have few to do with DML. DML is a special kind of beast.

POL

[OZZIOZZI]

I have read **many** of the posts on this thread, but admit I looked at the first 50-60 then skipped to middle and then towards the end. I just wonder if anyone has tried working within the limitations of DMR speaker panels rather than fighting to get the ultimate fullrange response from them? No offence to all the experimenters out there who are extending the range of human knowledge on this subject and having a ball at the same time

I recently looked at pics and reviews of old poly planar panels that resorted to multiple or various-shaped panels for bass, midrange and treble. Some commercial manufacturer's resorted to subs and supertweeters at the extremes of the audio spectrum. You all probably know who I am referring to, from 1960's to the present, from budget to uber-expensive. I love the look and construction of the Gobel panels and believe they are a suitable design to clone ( for private use only-of course  )

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

PS I have experienced the BMR sound with all it's wonderful properties, I am just not interested in chasing my own tail in search of the holy grail of one-panel nirvana.  Peace and goodwill to all on this fantastic thread and audiocircle forum in general.

[pol_bct]

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

If I understand your  question you are aiming at building a three-ways around DML, I personally think we can find better "classic" solutions for that task, because, when taken individually, DML does not measure very well in term of freq. response or distortion, but they are superior on others points.

The only interest I see in using DMLs is the wide-range possibility with same rapid decay time, coherent sound & phase, zero-filter hassle, constant directivity, big surface of radiation (low acoustical impedance),  ease of making, etc etc.  In a three-ways build, those quality would be spoiled.  Maybe a BMR would play better in a multi-ways configuration.

POL

[Fidel Costar]

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

What is "very fuzzy" ? After all, an Infraflex is a DML for bass duties only, and with a real speaker pushing the polyprop panel, not a cheap vibramassor shitty Chinese exciter. And even if theory is fuzzy, I don't give a sh..., as the sound is really good.

[OZZIOZZI]

Pol_bct  I guess I should have said "fullrange" rather than midrange. I like what jmanes is doing with his picture panels and 16x20 or 11x14 inches is a reasonable size for me. Of course this means using a woofer below about 150-200 Hz. I would only use a supertweeter if really necessary and crossed very high. I have a pair of DAEX25FHE-4 exciters already, which should work OK. 

The only problem I can see with is the "unobtainium" panel material that jmanes is using. Lets hope that he can source something similar on the open market. One panel material I have found is used by boatbuilders and aerospace industries which is a composite of end- grain balsa wood (good for damping) laminated on both sides by a thin layer of hard composite material using epoxy. My thought was to approach boat builders or caravan ( travel trailer) manufacturers for offcuts. This stuff is used for cladding of interior bulkheads, cupboards etc to save weight and space.

Mirekti's idea is close to what I had in mind too. Fullrange panel with sub.

I would be very interested in pics of jmanes panel showing exciter mounting methods and attachment of panel to frame. From my research, those two areas seem very important for best sound from exciter driven panels.

[pol_bct]

OZZIOZZI, I understand the underlying motivation of wanting something "reasonable" but I'm afraid you'll be desapointed by the end result. If compacity or WAF are strong arguments, there are better solutions aroud than DML.  DML do really need big surface to work properly, it's easy to get the numbers, the Xmax of a DML barely reach 1mm, if you want the sound of a simple 8"  (21cm) you need at least half of a square meter. My panels are 4,8m² and I crave for more. (impulse of my panel, with windowing)



POL