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Foam panel + exciter speakers sound .... really bad !!??

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  • Foam panel + exciter speakers sound .... really bad !!??

    Hi guys, I just had to try the flat panel speakers that are supposedly the greatest sounding things in the entire universe and....wow do mine sound bad. I'm thinking....I must have messed something up or something, there is no way anybody could listen to this thin, tinny sound and think it's good, right?

    I used this exciter

    https://www.parts-express.com/Dayton...ableshopping=F

    and this foam

    https://www.lowes.com/pd/Kingspan-In...ion/1000236635

    I sanded the foam both sides and used contact spray to attach super light fabric to the panel, glued the exciter in the 3/5 2/5 location, hot glued some cotter pins, hung it on the wall with 6# fishing line (the only connection between the panel and wall), and fired it up. Wow, what a disappointment.

    My comparison speakers are the Overnight Sensations and the SLA line arrays from bill fitzmaurice

    https://billfitzmaurice.info/SLA.html

    Did I screw up the build somehow? Buy the wrong exciter? Or are these just not all they are cracked up to be? Thanks for any comments you may have

    Joe

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  • #2
    https://techtalk.parts-express.com/f...l-speaker-love

    Comment


    • #3
      Originally posted by Fastskiguy View Post
      Hi guys, I just had to try the flat panel speakers that are supposedly the greatest sounding things in the entire universe and....wow do mine sound bad. I'm thinking....I must have messed something up or something, there is no way anybody could listen to this thin, tinny sound and think it's good, right?

      I used this exciter

      https://www.parts-express.com/Dayton...ableshopping=F

      and this foam

      https://www.lowes.com/pd/Kingspan-In...ion/1000236635

      I sanded the foam both sides and used contact spray to attach super light fabric to the panel, glued the exciter in the 3/5 2/5 location, hot glued some cotter pins, hung it on the wall with 6# fishing line (the only connection between the panel and wall), and fired it up. Wow, what a disappointment.

      My comparison speakers are the Overnight Sensations and the SLA line arrays from bill fitzmaurice

      https://billfitzmaurice.info/SLA.html

      Did I screw up the build somehow? Buy the wrong exciter? Or are these just not all they are cracked up to be? Thanks for any comments you may have

      Joe

      Click image for larger version

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      Technically no , you did not screw up that build. That design is a beginners design intro into DML technology. The exciter you chose IMO is one of the worst exciters. Using a better exciter could increase sound quality but only a little. Sound quality of DML is mostly based on ones build design and the better the design the better the sound quality.

      Most intro level conventional book shelf speakers would sound better then that DML build. Even the cheap Pioneers from Andrew Jones or entry level polk audio speakers would sound better. Those that say that DML design sounds good are amateurs and cant differentiate between that DML designs exaggerated sound and high fidelity sound.

      DML bending wave have a lot of potential but not many know how to bring out that potential to its fullest.

      When you step up your design they can sound way better like these DML speakers from Sheet Control.

      Sheetcontrol DML speakers: far and near field test with microphone - YouTube

      Step even further by combining DML bending wave technology with conventional cone drivers like Manger audio.



      Manger Audio P1 - YouTube


      Or Using a BMR driver with a conventional cone like Cambridge audio aero speakers.

      Or the ultimate in DML and conventional cone driver like these super expensive 100k Goebel speakers.


      Goebel Highend Loudspeakers, Epoque Reference and Baforce Fine, Kronos, CH Precision, High End Munic - YouTube


      Comment


      • #4
        A 96 page thread...would you happen to have a short summary?

        Comment


        • djg
          djg commented
          Editing a comment
          Sorry, never read it.

      • #5
        Originally posted by Unbiasedsound View Post

        Technically no , you did not screw up that build. That design is a beginners design intro into DML technology. The exciter you chose IMO is one of the worst exciters. Using a better exciter could increase sound quality but only a little. Sound quality of DML is mostly based on ones build design and the better the design the better the sound quality.

        Most intro level conventional book shelf speakers would sound better then that DML build. Even the cheap Pioneers from Andrew Jones or entry level polk audio speakers would sound better. Those that say that DML design sounds good are amateurs and cant differentiate between that DML designs exaggerated sound and high fidelity sound.

        OK well that makes sense. I didn't know which exciter to get and got this as a recommendation from the person at PE. The one he really recommended was out of stock so we went with this one.

        As for the links...those looked like commercial speakers...are the DIY? Or was this an example of how good flat panels have the potential to sound?

        Joe



        Comment


        • Unbiasedsound
          Unbiasedsound commented
          Editing a comment
          Those commercially made speakers are examples of a DML's potential.

      • #6
        Originally posted by Fastskiguy View Post
        Or was this an example of how good flat panels have the potential to sound?
        Speakers using distributed modes (resonances) have the advantages of being relatively low cost and having a wide passband but this comes at the inevitable cost of some sound quality. The frequency range with a low number of resonances is inevitably less than smooth and optimising it takes a fair amount of development probably best done on a computer. This makes good examples fairly DIY unfriendly. The best DIY ones I have heard were demonstrated about 15 years ago with some relatively simple strongly percussive music (Stimela IIRC). When asked about more complex large scale orchestral music the demonstrator said that would be less satisfactory and declined to demonstrate. I would suggest this is around the best you can reasonably shoot for. Don't expect to match the sound quality of well sorted conventional speakers but after a fair amount of development they can sound OK.

        Comment


        • #7
          Originally posted by andy19191 View Post

          Speakers using distributed modes (resonances) have the advantages of being relatively low cost and having a wide passband but this comes at the inevitable cost of some sound quality. The frequency range with a low number of resonances is inevitably less than smooth and optimising it takes a fair amount of development probably best done on a computer. This makes good examples fairly DIY unfriendly. The best DIY ones I have heard were demonstrated about 15 years ago with some relatively simple strongly percussive music (Stimela IIRC). When asked about more complex large scale orchestral music the demonstrator said that would be less satisfactory and declined to demonstrate. I would suggest this is around the best you can reasonably shoot for. Don't expect to match the sound quality of well sorted conventional speakers but after a fair amount of development they can sound OK.
          Hey makes perfect sense but I just don't understand why all of the youtube videos out there are raving about how awesome slapping an exciter onto a piece of styrofoam is supposed to sound. I mean....what is going on there?

          As for me...it's back to a more conventional speaker. Thanks for the comments

          Joe

          Comment


          • Unbiasedsound
            Unbiasedsound commented
            Editing a comment
            Like I said before a DML's sound quality is based mostly on ones design, the better the design the better the sound. Dont let that beginners intro design discourage you from building a better design. If you actually hear a good DML design in person you will understand what the fuss is all about.

            The easier route is to use a BMR driver and combine them with conventional cone drivers, like the Philharmonic BMR towers and or bookshelves.

            https://www.audioholics.com/tower-sp...ilharmonic-bmr

        • #8
          Originally posted by Fastskiguy View Post
          I just don't understand why all of the youtube videos out there are raving about how awesome slapping an exciter onto a piece of styrofoam is supposed to sound. I mean....what is going on there?
          Presumably they want you to view their videos to help with their online status and financial income. Exaggerated claims about the performance of cheap or free stuff is an effective and common tactic.

          Comment


          • #9
            Originally posted by fastskiguy View Post

            hey makes perfect sense but i just don't understand why all of the youtube videos out there are raving about how awesome slapping an exciter onto a piece of styrofoam is supposed to sound. I mean....what is going on there?

            As for me...it's back to a more conventional speaker. Thanks for the comments

            joe
            one weird trick speaker companies don't want you to know!!!!!1!111!
            Isn't it about time we started answering rhetorical questions?

            Paul Carmody's DIY Audio Projects
            Twitter: @undefinition1

            Comment


            • #10
              Has anyone ever seriously considered exiters and foam panels as even medium fidelity? DML's are so compromised in every way. Maybe a fun and cheap weekend experiement.
              Craig

              I drive way too fast to worry about cholesterol.

              Comment


              • Unbiasedsound
                Unbiasedsound commented
                Editing a comment
                I have considered my design as mid to high fidelity when compared to entry level and or older models of Magnepan. Every driver has its compromises especially one that is used as full range as DML's arent very different from conventional cone drivers. Just because you failed (and or others you know) in building a good sounding mid-hi fidelity DML panel it doesnt mean others have and or cant build a good one.

              • PWR RYD
                PWR RYD commented
                Editing a comment
                LOL at being a failure at DML panels

              • Unbiasedsound
                Unbiasedsound commented
                Editing a comment
                Well you said they are not even medium fidelity. Which means you havent heard a good sounding medium fidelity DML panel.

            • #11
              Originally posted by PWR RYD View Post
              Has anyone ever seriously considered exiters and foam panels as even medium fidelity? DML's are so compromised in every way. Maybe a fun and cheap weekend experiement.
              NXT has been pretty serious about the applications of DMLs for a few decades. They have put in significant R&D in an effort to find a profitable niche but with only modest success at best. High fidelity was never an application area but they did need to build a perception that the sound quality was OK (e.g.) if they were to get traction with consumer goods like TV screens, surround speakers, mobiles or whatever.

              You can find the BMR derivative in expensive audiophile speakers like the £30k Node which I have heard and it performed well though SPL limited. Superior to the best DML I have heard but that was DIYed for less than 1% of the price. Well designed conventional speakers could provide better technical performance for £30k but that isn't really what the Node is about as a product.

              I suspect DMLs are pretty much the same as "full range" drivers, dipole speakers, etc... which a few DIY speaker folk get enthusiastic about but which possess one or two significant cons that prevent them being adopted commercially as high technical performance speakers. Playing about with this sort of thing can be fun though and I would encourage rather discourage people with an interest to have a go at seeing what they can develop.

              Comment


              • Unbiasedsound
                Unbiasedsound commented
                Editing a comment
                Like you stated NXT was never into high fidelity as they were more for live performances like concerts. One of the advantages for concert sound is DML panels have way less microphone feed back then conventional cone speakers.


                https://www.youtube.com/watch?v=VbNNk-9GMRo


                DML's dont have to be used as full range. It can be used as 2 ways or even 3 ways with Xovers. It can be combined with conventional cone drivers and or a subwoofer.
                Last edited by Unbiasedsound; 11-18-2021, 08:55 PM.

            • #12
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              I built some 2’x2’ DML panels using the pink foam, sanded then coated with thinned and dyed wood glue. My exciters were the thrusters - and they sounded quite good. It does take a while to get used to their omnidirectional output and I thought the side with exciter on it did have better highs. The speakers played loud and clear.

              Three things that I would have not done on the OP’s panels are - the cloth, which greatly dampens output - the mounting style the OP used which I think limits movement and is probably MOST important (mine hang freely from thin paracord), and mounting near a wall. The panels seem to sound best at least two feet away from any wall..

              BTW - mine were up higher than I would have liked ‘cause I wanted to hear them from anywhere in the room. I put them above couch level. They worked well and sounded good - but still didn’t make enough bass. Rather than experimenting with larger panels I switched speaker styles completely - someone gave me a pair of Peavey SP1 mkIII’s to play with.
              “Hear angel trumpets and devil trombones - you are invited!”

              Comment


              • Unbiasedsound
                Unbiasedsound commented
                Editing a comment
                I agree about the cloth over damping the panel...The only type of cloth that I found that can be used on the panels are actual cloth used specifically for speakers. The speaker cloth I used are the ones I bought from P.E.

                I agree also as these speakers function like Open Baffle speakers in which they need to be at least 2ft. away from any walls as they use the reflected energy.

                DML speakers placement should be close to and around ear level depending on how far back you are sitting.

                Also DML's work really great with conventional cone powered subwoofers and even better with Open baffle type of powered subs.

            • #13
              Since exciters/BMR drivers are fairly cheap some people think that there sound quality wont be as good but like I said its all design dependent. Sure if big brand name companies made high quality hi fidelity exciters they would sound even better. The exciters available now are very limited and not the highest of quality. Some of the exciters voice coil arent even aligned accurately which can effect sound. I know as I had to throw away brand spanking new exciters because they didnt sound right since quality control is not that high with some of those cheaply made exciters.

              Most people over time give up on DML's as they are either not serious about it and or dont know how to design there panels to sound good. Most just chalk exciters up to a fun novelty experiment but dont seem to realize there true potential.

              I bet anyone if yawl heard my panels you will realize the potential of DML technology. I just finished building my "Tower", DML panels and they sound just as good as my small sat. panels and or better due to a new technique I have learned from designing the Towers. I am going use this technique and tweak my smaller panels to see if it will work.

              Listening to my Tower DML panels as I type and they sound phenomenal.

              Comment


              • #14
                Originally posted by Unbiasedsound View Post
                I bet anyone if yawl heard my panels you will realize the potential of DML technology. I just finished building my "Tower", DML panels and they sound just as good as my small sat. panels and or better due to a new technique I have learned from designing the Towers. I am going use this technique and tweak my smaller panels to see if it will work.

                Listening to my Tower DML panels as I type and they sound phenomenal.
                Do you have a build thread you can link to?
                If not, could you make a dedicated build thread?
                I know you've answered a lot of questions in the big DML thread, but I think something more organized around your current build would be easier for others to follow along with.
                My first 2way build

                Comment


                • #15
                  No I dont have a build thread. If I was going to make a build thread I would have posted it in the project gallery.

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