Audio experts weigh in on this please

[rick844]

Im confused. Either this guy is crazy or hes onto something. Please advise on your thoughts on this.
I am quite curious

https://m.youtube.com/watch?v=CKIye4RZ-5k

[technodanvan]

I was just reading a thread about something similar at PE, except there they were coating the panels with watered down glue to stiffen them up a bit. I suppose anything can sound pretty good with enough EQ?

For what it's worth, it did sound pretty impressive as far as Youtube videos go. I'd like to hear a system of exciters and panels sometime, just for grins. It's a fairly inexpensive project to set up.

[5th element]

Okay.

[rick844]

So, is this a gimmick or is this something that is a potential useful application?

[Bear]

So, is this a gimmick or is this something that is a potential useful application?

My take, and I'm far from an expert...

• Different materials have different absorption properties (hey look! Columbus just discovered the "New World"!)
• Owens Corning panels are pretty good at what they do (not cheap, though)
• Diffraction matters (changing geometries and location of the transducer)
• Multiple layers helps a lot (welcome to constrained layer damping
• Rigid foam is Good Enough for small drivers

The pile of horse manure? Pay attention to that room. In the grand finale it looked like he was in a Mark 1 Mod A steel shell commercial warehouse. The acoustics would be terrible for the floor reflections, but if you lifted the drivers high enough, then basically anything would sound "open an airy" -- because the room is open and airy. That's it from my curmudgeonly Sunday.

Yeah, and then there's that DSP thing...

[Kal Rubinson]

Im confused. Either this guy is crazy or hes onto something. Please advise on your thoughts on this.
I am quite curious


https://m.youtube.com/watch?v=CKIye4RZ-5k

I was just reading a thread about something similar at PE, except there they were coating the panels with watered down glue to stiffen them up a bit. I suppose anything can sound pretty good with enough EQ?

For what it's worth, it did sound pretty impressive as far as Youtube videos go. I'd like to hear a system of exciters and panels sometime, just for grins. It's a fairly inexpensive project to set up.

I didn't see the OPs reference because I don't do UToob, so I am inferring what it shows from your post. Coating the side edges of OC panels is a common practice to add physical stability with minimal (but measurable) impact on absorption. Painting it on the major surfaces (front/back) is sometimes done with the intent to reduce HF absorption in situations where there is a requirement to use so many panels for adequate MF/LF absorption results in unwanted dulling/absorption at HF. Some vendors add a thin skin for a similar effect.

[rick844]

Wut? Im only asking if this is something worth looking into, or is this just a joke.

[technodanvan]

I didn't see the OPs reference because I don't do UToob, so I am inferring what it shows from your post.

Yup, you nailed it! Have you seen applications where these are actually in use?

Wut? Im only asking if this is something worth looking into, or is this just a joke.

Well the title of the video is certainly clickbait - these are not the world's best speakers by a long shot and really should not replace anything in the home. I could see something like this being used commercially for sound reinforcement, maybe (like in a Wal-Mart or similar). It'd have to be cheaper than readily available alternatives though.

So, it's a 'joke' in that the title is misleading, it's not a joke in that exciters really exist; Dayton makes several. Worth looking into for home use? Probably not unless you like tinkering for the sake of tinkering.

[rick844]

Yup, you nailed it! Have you seen applications where these are actually in use?



Well the title of the video is certainly clickbait - these are not the world's best speakers by a long shot and really should not replace anything in the home. I could see something like this being used commercially for sound reinforcement, maybe (like in a Wal-Mart or similar). It'd have to be cheaper than readily available alternatives though.

So, it's a 'joke' in that the title is misleading, it's not a joke in that exciters really exist; Dayton makes several. Worth looking into for home use? Probably not unless you like tinkering for the sake of tinkering.

Thats exactly what i was asking. Is this for real, or is it a waste of time. Click bait? Not sure what you mean. My original qiestion was, is this something that should be considered, or is it a waste of time

Sheesh.

[Norm]

Hi rick844,
The author of the linked YouTube video is not crazy, but also not onto the ‘world’s greatest speaker’ breakthrough he touts.

I often refer to the Alice in Wonderland rabbit hole metaphor commenting “that rabbit hole is a deep one” when discussing the branches technologies take. In HiFi speakers there are rabbit holes labeled “cone drivers”, “horns”, “electrostatic”, and “planar magnetic”. This rabbit hole would be labeled “distributed mode”. Unlike most of the others distributed mode loudspeakers (DML) do not attempt to get the vibrating membrane that is producing the sound to move like a unified piston tracing the electrical input into a mechanical analog. Rather DMLs encourage the radiating diaphragm to behave chaotically vibrating more like the surface of a pond rippling in response to a rock thrown into the water. Except in this case the rock is the exciter and the pond’s water is the diaphragm material. This is one of those interesting cases where something engineers spent decades achieving (rigid piston like diaphragm motion) is abandoned and what is usually considered a source of distortion (cone breakup) is encouraged as the preferred mode of operation.

DML may be a relatively new term but the idea is anything but new. When I was a freshly minted audiophile in the 1970s a South American firm Bertagni enjoyed some commercial success with their DML speakers using Styrofoam diaphragms.



Bertagni speakers, grills off



Bertagni speakers, grills on.

DML’s tend to radiate in a somewhat omnidirectional pattern, that and the mechanics of their panel + exciter architecture they often take the form of a panel speaker as seem in the Bertagni’s.

Bertagni and other early users of DML relied on cut-n-try design to determine how to shape the panels, materials to use, and where to clamp the panels and place the exciters. With exciters available from Parts Express and others this is a popular pursuit with DIYer’s. The depth of this rabbit hole can be judged by the 161 pages of posting at just this thread:
https://www.audiocircle.com/index.php?topic=70541.0.

By the turn of the century computer modeling of electro mechanical acoustic devices was sufficiently advanced to allow BMR’s to be modeled in CAD. Out of that research the now defunct NXT PLC (https://web.archive.org/web/20061221...ex.php?id=home) was founded to advance and market the technology. Details here:https://en.wikipedia.org/wiki/Distri...de_loudspeaker

Presently the Tectonic Elements’ (who ended up with NXT’s IP) drivers are the starting place for DIY efforts:

https://www.tectonicaudiolabs.com/audio-components/bmr-speakers/

https://www.tectonicaudiolabs.com/audio-components/audio-exciters/

For really high-end use the German company Gobel High End is the primary BMR user I am aware of. The rectangular carbon fiber panel seen in their Epoque line models is their in-house produced wide range BMR.

http://www.goebel-highend.de/technology.html

In conclusion “World’s Best Speakers!”?? No. Interesting rabbit hole, yes.

[technodanvan]

Norm,

Thanks for showing some real world samples, I had no idea these were actually used in hifi. Very interesting rabbit hole indeed.

[rick844]

Hi rick844,
The author of the linked YouTube video is not crazy, but also not onto the ‘world’s greatest speaker’ breakthrough he touts.

I often refer to the Alice in Wonderland rabbit hole metaphor commenting “that rabbit hole is a deep one” when discussing the branches technologies take. In HiFi speakers there are rabbit holes labeled “cone drivers”, “horns”, “electrostatic”, and “planar magnetic”. This rabbit hole would be labeled “distributed mode”. Unlike most of the others distributed mode loudspeakers (DML) do not attempt to get the vibrating membrane that is producing the sound to move like a unified piston tracing the electrical input into a mechanical analog. Rather DMLs encourage the radiating diaphragm to behave chaotically vibrating more like the surface of a pond rippling in response to a rock thrown into the water. Except in this case the rock is the exciter and the pond’s water is the diaphragm material. This is one of those interesting cases where something engineers spent decades achieving (rigid piston like diaphragm motion) is abandoned and what is usually considered a source of distortion (cone breakup) is encouraged as the preferred mode of operation.

DML may be a relatively new term but the idea is anything but new. When I was a freshly minted audiophile in the 1970s a South American firm Bertagni enjoyed some commercial success with their DML speakers using Styrofoam diaphragms.



Bertagni speakers, grills off



Bertagni speakers, grills on.

DML’s tend to radiate in a somewhat omnidirectional pattern, that and the mechanics of their panel + exciter architecture they often take the form of a panel speaker as seem in the Bertagni’s.

Bertagni and other early users of DML relied on cut-n-try design to determine how to shape the panels, materials to use, and where to clamp the panels and place the exciters. With exciters available from Parts Express and others this is a popular pursuit with DIYer’s. The depth of this rabbit hole can be judged by the 161 pages of posting at just this thread:
https://www.audiocircle.com/index.php?topic=70541.0.

By the turn of the century computer modeling of electro mechanical acoustic devices was sufficiently advanced to allow BMR’s to be modeled in CAD. Out of that research the now defunct NXT PLC (https://web.archive.org/web/20061221...ex.php?id=home) was founded to advance and market the technology. Details here:https://en.wikipedia.org/wiki/Distri...de_loudspeaker

Presently the Tectonic Elements’ (who ended up with NXT’s IP) drivers are the starting place for DIY efforts:

https://www.tectonicaudiolabs.com/audio-components/bmr-speakers/

https://www.tectonicaudiolabs.com/audio-components/audio-exciters/

For really high-end use the German company Gobel High End is the primary BMR user I am aware of. The rectangular carbon fiber panel seen in their Epoque line models is their in-house produced wide range BMR.

http://www.goebel-highend.de/technology.html

In conclusion “World’s Best Speakers!”?? No. Interesting rabbit hole, yes.

Thank you for taking the time to explain and add value to my thread. Your response was very informative and has sparked my curiosity a little bit, especially since in some of the examples you provided, seems to provide insight as to who may also be using this method. Also the rabbit hole analogy made perfect sense.

Hopefuly some of the others on this forum can gain from your input as i will.

Thanks again.

[5th element]

I think any of these panel technologies has promise for certain applications. I'd imagine that they can be made to work to reasonable levels of fidelity too but they are still limited by the laws of physics. You'll need insane displacement capabilities to reach decent, low distortion, SPLs in the bass. I can't see this happening. But then maybe that isn't the intended application. Get down to 100-150Hz and use a sub.

[technodanvan]

I think any of these panel technologies has promise for certain applications. I'd imagine that they can be made to work to reasonable levels of fidelity too but they are still limited by the laws of physics. You'll need insane displacement capabilities to reach decent, low distortion, SPLs in the bass. I can't see this happening. But then maybe that isn't the intended application. Get down to 100-150Hz and use a sub.

IIRC, Adire Audio tried doing a sub like this back in 2005 or so. I know they had a video but I can't seem to find it now. The thing looked dangerous, had an xmax of several inches operating in open air. I don't recall what the panel material was, but it certainly wasn't made from a drop ceiling panel!