Midwest Audio Fest

It’s that time audio enthusiasts! Registration for the 2019 Speaker Design Competition is now open! Visit for details and to list your speaker project. We are excited to see all returning participants, and look forward to meeting some new designers this year, as well! Be sure your plans include a visit to the Parts Express Tent Sale for the lowest prices of the year, and the Audio Swap Meet where you can buy and trade with other audio fans. We hope to see you this summer! Vivian and Jill
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DIY Flat Panel Speaker Love

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  • Originally posted by Brewster56 View Post
    Thanks for the EPS supplier link, Unbiased. I talked with a foam manufacturer who has Type IV EPS 1.8 lbs/cubic foot, which is equivalent to the 30 grams/liter for the ultra dense on the UK website. This manufacturer also makes Type XV which is 3 lbs/cubic foot. Do you think that even the higher density as that would be better still? I am going to make a hot wire cutter to make whatever thickness I need. I also asked him about aged EPS, which is used on EIFS stucco. It is aged for 6 weeks, so it can finish outgassing, to minimize shrinking. This would likely be best to do with our DML's before sealing them.
    Yes I believe the higher density would be better but you would have to adjust the thickness of the panel to 1/4inch. (5-7mm)….Stiffer the panel material the thinner you need to make them so that they can bend/flex.

    I don't really worry about the aging as by the time the EPS is made and ships to my door step its almost close to 6 weeks. lol


    • 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).


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


        • Ways to tune a panel.

          1. Simplest one (but very effective) is damping.

          2. Weights. (washers, glue, silicone, putty etc)

          3. Groves and channels. (only on the back side of panel)

          4. Various thicknesses through out a panel.

          5. Panel "SKIN" like paper, paint, mylar, cloth can even combine different skins on the same panel...Skin needs to be real THIN as well as light. Thinner and lighter the better.


          • 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


            • 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.


              • Originally posted by giorgioPETALK View Post
                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.....Picture was I think on pg.47


                • 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


                  • 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.


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


                      • 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.


                        • 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.


                          • I took this from another site from one who's first impressions into DML inspired him to this technology.
                            A heartfelt thanks to the pioneers in this thread, I owe you! My electrostatics never recovered from the move to France and I after days of diagnostics it appears I have a major panel rebuild before me. As that means yet more time without sounds I thought why not give these DML panels a try.
                            I read through this thread, which took some time, then threw together a couple of panels made from some cheap thin ply from the local DIY store. I used Dayton DAE32EP-4 Exciters and hooked it all up in the approved fashion.
                            Total cost 67 Euro and about two hours work. Not expecting much but needing some music I gave them a whirl.

                            Bloody hellfire!

                            First record was Vaughn William’s ‘A Lark Ascending’ by The Academy of St Martins in the Field. What a wonderful presentation. It’s a very distinctive soundstage but utterly convincing. I had read the descriptions of ‘being there in the room’ but I have heard that so many times before I had discounted the claims. Wrong! What a strange experience. The walls to the listening room have simply gone and you can literally walk into the soundstage, something I have never experienced before.
                            Next up was ‘A Walk in the Wild Side’ by some bloke called Lou Reed. Oh my days what fun! I am there in a NewYork club sitting a couple of tables back. When the Coloured girls did their thing I burst out laughing.

                            Then there’s the timbre of instruments. I have never, ever in all my days heard such a realistic piano sound, ever. Nor have I heard the accidental tap of a bow on a music stand in the middle of a violin concerto before, not like that, no so clearly defined it stood out against the music, a tiny but distinctive error.

                            There are a few things that I need to think about. Some recordings sound like a transistor radio, some sound utterly perfect, incomprehensible so considering the tiny outlay. I am going to have to do a deep edit on my collection. And it’s not just classical, jazz V rock. As I write this Lana Del Rey has begun ‘ Born to Die’ and it is ravishing.
                            I also think they need help from some decent subs but those subs are going to need to be very good to keep up with the quality. Both problems are very minor.

                            So I just wanted to say thank you to all the pioneers who have kept the flame burning for this extraordinary technology. Might be a long time before those panels get rebuilt. Might use the frames for something else. Colour me amazed.


                            • 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.



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