[phenix332]

Hello everyone,
So after I saw the Youtube video by Tech Ingredients on these DMLs a couple of weeks ago I was instantly intrigued. Since then i ordered two Visaton ex60s for first experiments and started to build some XPS panals.
I already experienced some of the properties these panels have. The LF  for example get much stronger when using 30mm thick material compared to 20mm XPS, also overall volume is really  dependent on panal size. All of that is probably nothing new to you but never the less fascinating to experience in person.

Now to my questions: Has anyone of you tried the method described in the video, where weights are placed to dampen some of the resonances? I see Bertagni has implemented something similar... I guess.
What thicknes of endgrain Balsa would be appropriate? In some other forum a person chose 3mm and said that thicker panals would make it sound slow/mushi? but in the video ist seems to be about 1/2". This material should also be interesting for a cfk laminate I can imagine (good dampening of the cfk resonaces) ? Kind of like tectonics panels.
After my order was already placed I read that the Visaton do not produce the best sound quality (still very impressed by the result),so for later builds I would chose a different one. Any suggestions? Is the Dayton Ultra still the one with the best "Hifi" potential or are there others that don't break that often?

I am really looking forward to your replies! In the meantime I will start reading on this paper which seems to be very informative: https://urresearch.rochester.edu/fileDownloadForInstitutionalItem.action?itemId=32717&itemFileId=182509 Do you know it?

[Bendingwave]

Hello everyone,
So after I saw the Youtube video by Tech Ingredients on these DMLs a couple of weeks ago I was instantly intrigued. Since then i ordered two Visaton ex60s for first experiments and started to build some XPS panals.
I already experienced some of the properties these panels have. The LF  for example get much stronger when using 30mm thick material compared to 20mm XPS, also overall volume is really  dependent on panal size. All of that is probably nothing new to you but never the less fascinating to experience in person.

Now to my questions: Has anyone of you tried the method described in the video, where weights are placed to dampen some of the resonances? I see Bertagni has implemented something similar... I guess.
What thicknes of endgrain Balsa would be appropriate? In some other forum a person chose 3mm and said that thicker panals would make it sound slow/mushi? but in the video ist seems to be about 1/2". This material should also be interesting for a cfk laminate I can imagine (good dampening of the cfk resonaces) ? Kind of like tectonics panels.
After my order was already placed I read that the Visaton do not produce the best sound quality (still very impressed by the result),so for later builds I would chose a different one. Any suggestions? Is the Dayton Ultra still the one with the best "Hifi" potential or are there others that don't break that often?

I am really looking forward to your replies! In the meantime I will start reading on this paper which seems to be very informative: https://urresearch.rochester.edu/fileDownloadForInstitutionalItem.action?itemId=32717&itemFileId=182509 Do you know it?

My design is based off of Bertagnis so my method of weight dampening is very similar.

In that Tech ingredients video which panel do you think had the most pronounced bass?

The reason for the Visaton and Dayton flat pack exciter dont have the best sound quality is due to there plastic coil being attached to the square flat plate which in turn is attached to the panel material. Most exciters plastic coil is attached directly on to the panel for best quality sound transfer...The square plates added weight and dampening properties hinder sound quality.

The Ultra and Thruster are good sounding exciters but have reliability issues...The DAEX30HESF, DAEX25SHF and the smaller DAEX25FHE are good sounding exciters that are reliable....Other exciters I would recommend from Tectonic is the Frog exciter TAEX25C10 and the smaller TAEX19C01.

[phenix332]

Then i will order two of the DAEX30HESF for the about 2'x3' large panals that are 30 mm in thicknes. I also thought about two smaller pannels only 20mm thick, for HF that are driven by the TAEX19C01. Would that be worth a try? How would I manage the different power ratings if I want to turn the volume up?
Sadly these exciters are about 50% more expensive so i would prefer  not to fry them.
I probably also will have to think about building a sub at some point. OB seems to fit well but are there any not so pricey drivers that ar suited?

[Bendingwave]

I just use a electrolytic capacitor for the high frequency exciter.....It would be worth a try if you have the knowledge to do so as the DAEX30HESF is  4ohms, while the TAEX19C01 is 8ohms.

Using the electrolytic capacitor you would need for both exciters to be 8ohms wired in parrallel for 4ohms.

You could start off with the smaller exciters like the TAEX19C01 which is around $6.00 used as the full range driver while the DAEX13CT exciter is used as the high freuquency with the electrolytic capacitor......The down side for using smaller exciters is that they wont play as loud as the bigger more costly exciters.

[koko007]

@Bendigwave

Could you make cook-book of your "Bertagni like speakers" like Rich did with his spakers:
http://projectgallery.parts-express.com/speaker-projects/dml-flat-pannel/

@Nickolay V
Could you tell me, where i can buy that panels?

[Bendingwave]

Sorry but I wont give a detail instruction to my design as one day I might want to get it patented.

You could just mimic Bergtagni's design and have really good sounding panels that would be way better then the average beginner type of DML panels....my design is just a step above bertagni's with everything being a bit more cleaner and accurate sounding with better highs, tighter more accurate bass, cleaner midrange. etc.

What separates bertagni's design from all other panels is that with Bertagni's design you will either have to have a CNC machine or know someone with a CNC machine and or you would have to be a master scultpter because Bertagni's design utilizes different thicknesses with many grooves, channels, IM traps as well as dampening weights and other dampening factors...Dr.Jose Bertagni was well ahead of his time in DML/BMR technology, I would even go out on a limb to call him a genius.

I for one had neither.....So it took me 2 years of polystyrene hand sculpting practice to get where I am at today and even at that it is no where near as accurate as a CNC machine.

These exciter technology has a lot of POTENTIAL....If more speaker manufacuterers realize this they would most likely be able to make a design even way better then mine.....There is only one speaker company that I know of that took Bendingwave technology seriously to the extreme which is the Goebel company and there over 100k bending wave speaker....Does the Goebel speakers sound better then my design? Heck yeah they do but they better since there speakers cost over 100k with millions of dollars that backed them up in the research and development department....My design cost me less then $200.00 a pair and around 2k that Ive spent on research and development within the past 3-4 years.

Still till this very day I am trying to make improvements on my panels as I am always learning making adjustments but it goes at a very slow pace as I do not have the extra funds to experiment with at a faster pace.

[samich]

Hi everyone,
I hope it's OK to post here even if it's been a while. I've already spent 2 hours reading this topic (still not finished). So interesting, thanks for sharing, everybody, especially Bendingwave   


I'm a newbie, but I would love to get hooked into building speakers and co. I love DIY, and building expensive stuff for cheaper 
And this NXT thing looks so promising.

For my first try, I want to build a very simple system with 2 panels that will be also decorative. It could be very cool to have music in the room, but without any visible speaker!

So I will buy high-density styrofoam, stick an art print on it, and hang it on the wall. Do you think it's a good idea?
I won't be able to round the corners, but I don't need the perfect sound, I just want it to sound better than the Amazon Echo in this room (should be easy to beat . I've read this tuto: http://projectgallery.parts-express.com/speaker-projects/dml-flat-pannel/

I bought 2 exciters model TEAX25C10-8 (because I live in Spain, and it was not easy to get the Dayton). Bendingwave, I've read that you also bought them for testing. What do you think of them? Is it good enough? How is it compare to the DAEX25FHE-4 for example? Because I already tried them on various surface (but without sticking it because I'm waiting for the styrofoam to arrive) and the sound is horrible for now  I hope it's normal.
I also plan to buy a subwoofer and integrate it into a furniture.

Thanks in advance for your feedback on my first project. Suggestions are more than welcome

[Bendingwave]

Hi everyone,
I hope it's OK to post here even if it's been a while. I've already spent 2 hours reading this topic (still not finished). So interesting, thanks for sharing, everybody, especially Bendingwave   


I'm a newbie, but I would love to get hooked into building speakers and co. I love DIY, and building expensive stuff for cheaper 
And this NXT thing looks so promising.

For my first try, I want to build a very simple system with 2 panels that will be also decorative. It could be very cool to have music in the room, but without any visible speaker!

So I will buy high-density styrofoam, stick an art print on it, and hang it on the wall. Do you think it's a good idea?
I won't be able to round the corners, but I don't need the perfect sound, I just want it to sound better than the Amazon Echo in this room (should be easy to beat . I've read this tuto: http://projectgallery.parts-express.com/speaker-projects/dml-flat-pannel/

I bought 2 exciters model TEAX25C10-8 (because I live in Spain, and it was not easy to get the Dayton). Bendingwave, I've read that you also bought them for testing. What do you think of them? Is it good enough? How is it compare to the DAEX25FHE-4 for example? Because I already tried them on various surface (but without sticking it because I'm waiting for the styrofoam to arrive) and the sound is horrible for now  I hope it's normal.
I also plan to buy a subwoofer and integrate it into a furniture.

Thanks in advance for your feedback on my first project. Suggestions are more than welcome

There are two ways to do it.

The first and most common way is to use the panels as "FREE FLOATING", like in Rich's design in the partsexpressgallery. Free floating means only the panel material is used with almost nothing touching the panels. This method is best suited to hanging on, in or near walls including ceilings.


The second way which is not as common is to use a "FRAME & SPLINE".....The panel material is held in place inside a frame structure while the spline holds and secures the exciter in place like a conventional cone speaker or BMR driver.  This method is best suited to be used on the ground with a short or tall stand (depending on the size of ones panels) just like a conventional type of speaker.

My design uses a "Frame & Spline".

Attaching a art print to the front of the panel can change the sound depending on the type and thickness of said art print material...I would rather just spray paint it with a light coat color of your choice.

Tectonics exciters have a warmer sound, while the Dayton exciters have a brighter sound with better high frequency....The Tectonic exciters also seem to have a touch more accuracy in the lower frequencies but will seem to lack some of the higher frequencies due to them being on the warmer side. My design uses two exciters per panel....I use the Tectonic exciters as the bass/full range drivers and the Dayton exciters as the high frequency exciters with just a high pass non polarized electrolytic capacitor.

Most materials will not sound that good, there is only a hand full of materials that sound good and high density (EPS) Expanded Polystyrene IMO is one of the best.

[samich]

Thanks a lot, Bendingwaves! Yes, I will try the free-floating technique.
The art print will just be a printed paper glued to the EPS panel. This is kind of important for my girlfriend approval  I'm willing to sacrifice a bit of quality, hopefully, there won't be a lot of difference. I'll test with and without. If it's really bad with the print stuck on it, I'll have to paint something beautiful myself then   
For the Tectonic exciters, glad to know that they are not so bad. I might even not need to supplement the sound with subwoofer, perhaps? But maybe use some other exciters or tweeters for the higher range?
I'm so eager to receive my panels 

[Bendingwave]

Bass is dependent on the size of the panels......Panels need to be at least around 16 inches or higher for ideal bass response.


Bass output from DML panels are equivalent to a pair of 6 1/2 inch-8inch woofers or a single 8-10inch powered sub....If you need more bass then you should use a sub.



If the highs are not sufficient enough then you could use a tweeter for the higher range frequencies. Most exciters high frequency response seems to gradually drop off at the 5khz range so you could use your high pass crossover at 5khz for the tweeter.

[Kame2]

Hey there, I just registered to join the DML-panel-community. I am not an audiophile person but find the idea of a simple flat panel that fills the room relatively evenly with music quite interesting. As a computer scientist I did a lot of research but only little experiments so far.

The first thing that I noticed is that from the formulas, the bass should get better with a thinner panel. But when I build a 5mm thick XPS panel it had less bass then the same size with 20mm thickness. I found the solution to the contradiction in the free floating edges. In short, the panel gets to wobbly so the waves cannot travel far enough before vanished. The solution is a frame, which even increases radiation efficiency. I simply glued some wood sticks around the panel and wow, good bass!

So now I was ready to build my first complete DML-speaker prototype. For the experiments I was just holding the exciter against the panels. I decided to first build one with a 20mm thick panel I prepared in parallel with the frame-experiments. Front view is very simple:


The back side shows the simple construction:


I first build it without spline-mounting then latter added the spline. I hoped to improve bass but I don't notice any relevant changes in the frequency response. As the rooms in which I measured were different, the frequency responses had some differences anyway so there might be some little differences in spline mounting vs. free.

Frequency response:


After I EQed the highs up the panel sounds very good to me. Using a 12W amplifier with volume knob at around 1/4th the panel produces loud music I enjoyed listening to. So the 40W Exciter should have enough headroom.

Next I want to experiment with a DAEX13-13-4SM as tweeter to maybe get some more highs. And after that I have many other ideas I want to try but very little time. So it might take a while until a next prototype is ready. Stay tuned

[Bendingwave]

Welcome Kame2.......Finally someone that actually read the post on this topic and is on the right track....Like Ive always said a spline and a FRAME is a must because it will make the panels sound better.


The DAEX 13 being used as a tweeter would sound best when used in the upper corner and with just a non polarized electrolytic capacitor at 4-6khz.


Good luck with your experiments.

[Kame2]

Regarding the frame I recommend the paper 'The effect of boundary conditions and ribs on the total radiation efficiency of submerged plates': https://eprints.soton.ac.uk/369232/1/Eprints.pdf
While the real behavior of a free floating panel is not as bad as the paper suggests, it becomes clear that a frame is the better choice. As a simply supported suspension is harder to get right I went for the completely clamped version and just glued the frame on the plate.

I am not sure if a spline improves the sound in all cases. It should help if the magnet is not massive enough to handle the deeper frequencies. But I think in my case the stiffness of the plate prevents the deep bass part.
But independent of the sound quality I think it is a good idea to support the mass of the magnet of this heavy exciter.

In respect to the tweeter I am with you. For the high frequencies the location of the exciter should not be critical and as the lower frequencies have lesser amplitude in the corners they are a good place to reduce bad interaction with the (little) mass of the tweeter.

[Kame2]

The title of the paper above should be 'The effect of different combinations of boundary conditions on the average radiation efficiency of rectangular plates' (URL is correct)
The title I wrote is an other paper I plan to read but did not so far.

[Zygadrson]

Hello all.

While I may be new to this forum, I believe some of you knew by father Zygadr (Rob Zygadlo) who I understand many of you discussed what I think was coined the Z panel Styrofoam speaker.

After reading through his previous posts, I am very curious about something my father spoke so passionately about.

I think, I may want to pursue making my own set or preferably buying a pair from one of you folk as a lasting memory to my dad.

If any of you can help me out with step by step instructions and material breakdown or rather can build and sell me a pair, please get back to me.

Many thanks

[Bendingwave]

This is Yamahas version of DML/BMR loudspeakers which uses a DML/BMR driver for the bass while combining a conventional cone type drivers for the mids and highs.


https://www.youtube.com/watch?v=XNGsFul8sXI&t=172s

[Bendingwave]

Hello all.

While I may be new to this forum, I believe some of you knew by father Zygadr (Rob Zygadlo) who I understand many of you discussed what I think was coined the Z panel Styrofoam speaker.

After reading through his previous posts, I am very curious about something my father spoke so passionately about.

I think, I may want to pursue making my own set or preferably buying a pair from one of you folk as a lasting memory to my dad.

If any of you can help me out with step by step instructions and material breakdown or rather can build and sell me a pair, please get back to me.

Many thanks

Welcome Zygadrson

From reading all these posts your father seemed very passionate about these DML panels.

His choice of panel material (which is also my choice) is High density Expanded Polystyrene (EPS)

Everyone has different designs so it would be best if you pursued this on your own and try to make your own design that you feel sounds good to you. Design possibilities are endless.

[Bendingwave]

Regarding the frame I recommend the paper 'The effect of boundary conditions and ribs on the total radiation efficiency of submerged plates': https://eprints.soton.ac.uk/369232/1/Eprints.pdf
While the real behavior of a free floating panel is not as bad as the paper suggests, it becomes clear that a frame is the better choice. As a simply supported suspension is harder to get right I went for the completely clamped version and just glued the frame on the plate.

I am not sure if a spline improves the sound in all cases. It should help if the magnet is not massive enough to handle the deeper frequencies. But I think in my case the stiffness of the plate prevents the deep bass part.
But independent of the sound quality I think it is a good idea to support the mass of the magnet of this heavy exciter.

In respect to the tweeter I am with you. For the high frequencies the location of the exciter should not be critical and as the lower frequencies have lesser amplitude in the corners they are a good place to reduce bad interaction with the (little) mass of the tweeter.

If you look at all the professional manufacturers of DML/BMR loudspeakers from Bertagnis, Sony's APM's, Technics SB flat driver series, Yamahas Ear speakers to Podiums you will notice they ALL use some sort of frame and spline....There is a reason why all of these professional loudspeaker manufacturers utilize a frame and spline.

The spline is needed to support the magnet on higher excursions as it needs something to push against....with nothing to push against to support the magnet on higher excursions the magnet will rattle and make a lot of noise and also some percentage of energy will be lost resulting in lesser/weaker vibrations going all into the panel....not sure if that made sense but oh well. LOL

[Odal3]

This is Yamahas version of DML/BMR loudspeakers which uses a DML/BMR driver for the bass while combining a conventional cone type drivers for the mids and highs.


https://www.youtube.com/watch?v=XNGsFul8sXI&t=172s

Here's some historical info on the yamaha ns20. https://europe.yamaha.com/en/products/contents/audio_visual/hifi_components/hifi-history/speaker/index.html

[Bendingwave]

Here's some historical info on the yamaha ns20. https://europe.yamaha.com/en/products/contents/audio_visual/hifi_components/hifi-history/speaker/index.html

Thanks for the historical article Odal3.

Someone on Audiokarma said that Yamaha licensed the technology from Bertagni/BES....which is probably why its shaped that way like an ear. If you look at bertagnis design its shaped very similar.

https://img.usaudiomart.com/uploads/large/1096124-bertagni-electroacoustic-systems-bes-sm100-speakers.jpg