DIY Flat Panel Speaker Love

[Zene]

Brew... I want to try the Tectonic TEBM35C10-4 first; no good reason other than flat to 20k.
Will be either a 3 or 4 way. All other exciters will be Dayton DAEX25'S. Good to about 8 -10k for crossing to BMR. Not concerned about hearing above that (old), just want to keep any high freq distortion from the 25's. I'm a firm beliver in eliminating as much dopler distortion as possible.
Only changing panels' size and materials.
OB woofer (Klipsch 15). Active 4 way crossover for versitility. No high spl output needed. NO eq ever, never, nada. Stuborn and old school. A lot of times it's the room, not the speaker.
On 3 or 4, will try to do 3 first; If not satisfactory can do one larger panel and one small. Still using the 25's for both. Means the crossover point should be flawless.
Keep posting progress. Some of us need all the input possible as you can tell by the # of posters we are a dying breed. I was hoping to spark some opposition from the dyed in the wool full range guys. Pushing any speaker to it's limits is not the answer.
Heed Unb...'s panel recommendations (post #1179).

[giorgioPETALK]

in regard to tuning the DML panels how would you do it? thanks
g

[Unbiasedsound]

You cant tune a panel but you can tune a fish. LMAO

[giorgioPETALK]

thank you, what about a wood panel? Also, I was reading about bracing the exciter to the panel, would you have a picture to share about that?
Thanks so much for your help and advise. Giorgio

[bradley.s]

You can tune like this. Buy materials from the store. If you aren't happy with the materials return them and try something else. When you're happy make it permanent.

[Unbiasedsound]

thank you, what about a wood panel? Also, I was reading about bracing the exciter to the panel, would you have a picture to share about that?
Thanks so much for your help and advise. Giorgio

Most of those techniques should work on the wood panel as well.

[Unbiasedsound]

Fine tuned my panels and now they sound even better. I bet if Kornbread heard my panels I could make him a believer again. LOL

[bradley.s]

This is probably going to fail but I'm doing it anyway. I picked up a composite honeycomb panel at the carbon fiber store. Composite honeycombs, cloth facing. I coated one side with epoxy resin then layered stands of carbon fiber that fans out as it goes down the panel. I left one side uncoated, just the plain cloth material. Panel is 1/2" thick. Each piece is 2.75" wide cut at different lengths. I plan on using these to make two tall, thin panels with digital signal processing -- FreeDSP -- to make it behave like a curved CBT array. Because it's a flat CBT without an enclosure I'll place it away from the wall like an electrostat. Maybe the virtual CBT will appear to arc backward to send the soundfield forward and also arc forward to send the soundfield into the wall for reflections.

Again, it will probably fail. On the other hand, if it does work it will be an inexpensive CBT array.

[Unbiasedsound]

Interesting design. How many exciters per panel? Let us know the outcome, good luck.

[bradley.s]

At present: 5, 3, 2, 1, and 1 exciters. That's half the number of drivers appropriated in each of the five sections of the CBT24K. If it doesn't work I'll have a lot of work peeling them off without damaging them. If it does work I'll create a center channel with a horizontal virtual CBT. So very DSP and labor intensive but low material costs. Although, maybe not labor intensive compared to making an enclosure and crossovers.

[Unbiasedsound]

If I were to do a line array type of DML or I should say BMR type of speaker I would use multiple separate panels with one exciter on each panel instead of multiple exciters on a single panel.

Just saw a new vid of Sheets controls panel and from the sound, it seems they made improvements to it. https://www.youtube.com/watch?v=L5zJ4C9mYLk

[Kornbread]

I have a pair of Apogee Acoustics Caliper sigs, and although my experiments with exciter technology were not as extensive as some, I could never mistake the sound of any of my admittedly experimental dml panels for an Apogee planar.

Was I able to achieve better sound reproduction than 'WalMart' offerings? Sure.

Did they offer a diffuse type of sound? Yes.

Does the technology have potential? I believe so.

[Unbiasedsound]

Kornbread besides your own panels have you heard other DML manufacturers like Podiums? Bertagni's? Goebels? Sheet control? NXT? etc

[Kornbread]

And don't forget the Russian's business (cannot remember his nor his company's name), who posted way back in the diyaudio thread and went on to use the panels in professional sound reinforcement.

No, I have not heard commercial iterations of the technology. It would be quite revealing if people started showing up at the diy events with dml panels.

I feel NXT had strong potential in the autosound industry but now the effort seems to have disappeared. Curious as to what happened to that effort.

[geosand]

New to the board and this thread. Some questions that hopefully haven't been asked too many times before.

On panel material: Has anyone tried Polyisocyanurate foam board. Its denser and thus a bit heavier than say foamular 150 and maybe a bit more dense than foamular 250. https://www.homedepot.com/p/R-Matte-...stomer_reviews

On reducing board resonances, in the original Tech Ingrdients video, during the part on reducing resonances, just before he mentions using weights placed at the 2/5,3/5 locations of the sub-divided rectangles, he quickly mentions you could also just cut holes at those locations. Has anyone tried this or determined how big/small those holes would be? Seems like it might work better than adding weights/mass at the resonant points?