Speaker Cabinet Design Considerations

[GelbeMusik]

And still there is absolutely no evidence for an impact of cabinet vibrations on sound quality.

 

[maty]

I have used viscoelastic material in different loudspeakers that I have modified, mine and others, since June 2011. The improvement is very evident with good recordings + high dynamic range. Tecsound SY70 (autoadhesive).

Old picture, June 18, 2011

Sandwich: Tecsound SY70 + acrylic sealant + Tecsound SY70 + acrylic sealant + compacted fiberglass

English PDF, page 6 - Tecsound SY
http://www.texsa.com/en/files/doc60/folleto-tecsound-angl-low.pdf

 

[GelbeMusik]

I have used ...
English PDF, page 6 - Tecsound SY
http://www.texsa.com/en/files/doc60/folleto-tecsound-angl-low.pdf

I hold a small German patent on the use of similar tech within loudspeaker enclosures, not sacrificing precious volume, which makes it a bit special. This was born out of bad feelings. About people actually fantasizing huge impact of cabinet wall vibration of loudspeakers on sound quality. ( The effectiveness was proved. )

I only wanted to show, eventually, that there is no real (!) interest in addressing the topic. Because everybody in the industry knows, there is no problem. The use of massive measures only pleases the un-educated expectations of customers. Everybody would be able to feel, by touch, the vibrations. Make up a story about it, done. There is something that doesn't belong ...

From an engineering perspective: is it actually feasable to build loudspeakers using, what was it, 300 pounds of ( quite humble ) polyurethane? For everybody? As a standard? If it was recycled plastic like polyproylene, sound proof and rigid and ... we could place the garbage where it belongs.

Regarding the price, right, 150.000 dollars? For loudspeakers that "transport the feelings of" ( so the video )? People need 150.000$ so that feelings are transorted to them? Self evident that is, as satire.

 

[maty]

The small loss of volume (was in a strange big 2-way + supertweeter loudspeaker -> two layers of Tecsound SY70) is compensated by fiberglass, I say.

 

[GelbeMusik]

The small loss of volume (was in a big 2-way + supertweeter loudspeaker -> two layers of Tecsound SY70) is compensated by fiberglass, I say.

Uhh, box vibration. What about 150 pounds of lead?

 

[richard12511]

I hold a small German patent on the use of similar tech within loudspeaker enclosures, not sacrificing precious volume, which makes it a bit special. This was born out of bad feelings. About people actually fantasizing huge impact of cabinet wall vibration of loudspeakers on sound quality. ( The effectiveness was proved. )

I only wanted to show, eventually, that there is no real (!) interest in addressing the topic. Because everybody in the industry knows, there is no problem. The use of massive measures only pleases the un-educated expectations of customers. Everybody would be able to feel, by touch, the vibrations. Make up a story about it, done. There is something that doesn't belong ...

From an engineering perspective: is it actually feasable to build loudspeakers using, what was it, 300 pounds of ( quite humble ) polyurethane? For everybody? As a standard? If it was recycled plastic like polyproylene, sound proof and rigid and ... we could place the garbage where it belongs.

Regarding the price, right, 150.000 dollars? For loudspeakers that "transport the feelings of" ( so the video )? People need 150.000$ so that feelings are transorted to them? Self evident that is, as satire.

Wilson Audio is one that uses super, extremely well braced cabinets. Their WAMM Master Chronosonic is 900lbs(408kg) per channel. I've always been curious how much that helps. The biggest downside I see to that is that I can't play around on my own with speaker positioning and toe in. I live alone, and I'm not strong enough to move a 900lb speaker.

 

[richard12511]

People spending this sort of money want to choose their own amp.
Probably wrong and good actives have been available but suffering from this bias in the market for decades.
The Meridian M1 was offered in the 1970s but suffered from the same problem, as all their subsequent excellent speakers have.
Pro audio isn't a hobby so doesn't suffer the same illogical market.

Such an unfortunate situation, but I understand it. I watched a Steve Guttenburg video once where he was explaining why he greatly prefers passive speakers and how active speakers can never hope to sound as good as passives. His argument was essentially that speaker manufacturers specialize in making speakers, and amp manufacturers specialize in making amps, and therefore the amplification in active speakers is always going to be low fidelity when compared to amps from companies like First Watt. I understand the logic, but I strongly disagree. Sadly, I think most "high end" audiophiles agree.

 

[Deleted member 14468]

Looks really impressive, but man, why didn't they go active??? $150,000/pair is essentially cost no object, so why not? Is it possible that the design is somehow improved by staying passive?

I tend to agree with what another person put -- high-end audiophiles tend to like to select their own electronics, for better or worse.

Doug Schneider
SoundStage!

 

[Rick Sykora]

Am not a high-end audiophile and like to pick my electronics too. For that matter, like to pick my software as well.

I also like to have an idea of what is in my signal path. Do not see major benefits from lots of dsp that acts independently and possibly redundantly. It reminds me of the home theater situation where you would get surround decoding in both media player and the HTR or processor.

While dsp can be used to improve the speaker’s sound quality, not clear that that means it has to go in the same cabinet. I used to work in industrial electronics. This often required better noise and shock and vibration specs than commercial products. Circling back to cabinet design, putting electronics inside speakers creates a need for better vibration considerations and (likely thermal ones too). This all adds expense to the design to do right and does not necessarily yield significantly better sound than external electronics can. The upgrade path also seems more challenged as most integrated solutions tend to be too.

Finally, sensor integration is another area of potential challenges. As long as room correction requires microphone(s) to achieve, unless my speaker has the comparable measurement capability as a surround sound processor, does not seem likely it will be as functional. If it is, I may be paying for measurement capability in more than one part of my system. This seems redundant, more complex and prone to introducing integration problems too. So, while an active design can be better, am still not seeing it. One of the areas of clear active speaker benefit is removal of big inductors in the signal path. An active bass subsystem addresses this effectively and also handles frequencies where room correction has added benefits. However, even in this case, no need to put the electronics in the speaker to get the benefit either.

 

[GelbeMusik]

I watched a Steve Guttenburg video once where he was explaining … His argument was essentially that speaker manufacturers specialize in making speakers, and amp manufacturers specialize in making amps, ...

This is sort of a conspiration theory. It arguments with the matter of fact, that one doesn't know what 'they' do. So one might suspect, that they don't do well (enough). Clue is: that is considered a valid and final argument. The theorist refrains from gathering real information, but focusses on developing colorful assumptions in every detail. ( The flat-earther for instance would claim, that 'they' would lie anyway, the highender is more humble, saying that 'science' cannot reveal the 'truth'. )

With highend audio brabble there is the same question to be answered: why the heck should it be important in the first place?

So, here it comes: to what degree is it important that Mr Guttenberg has a better personal experience with his stereo once he uses a non-integrated amp/speaker combo?

You get it right, it comes down to him not knowing about real (!) audio tech too much, but still requesting eagerly to be serviced to total satisfaction. This mindset is well known from humans, and highly respected. Every young parent would agree.

To have people into this mindset goes back to the vile claim, that stereo has some real grounds in reality, that, if the effort is big enough something more can be revealed. Something like "feelings" ( as said in the video above ).

To make this business work one needs people who do not (yet?!) feel the music, who are foolish and are wealthy enough to spend hilarious money on a stereo set, and who are eager enough to never learn.

 

[VeerK]

This is a great thread, with so many wonderful contributions and learning resources.

Based on the posts here, Reddit, and DIYAudio I was curious to get opinions on the following:

Cabinet Materials: Slate
Damped Bracing: KEF white paper
Viscoelastic material: Sorbothane or Poly 2K

Conceptually, I like how KEF opted to damp brace the back of the drivers. Has anyone tried a similar assembly as DIY? I read something from Geddes on DIYAudio a few years back and he didn’t seem to love the idea, will try to post a link. Maybe I missed it, but which poly2k brand did Geddes recommend? Sorbothane looks like a nice ready made product but I don’t know how it compares to Poly.

I’ve also been reading up on cabinet materials and I think in June someone on Reddit showed a graph where slate was more than twice as effective as MDF for reducing panel resonance. Slate tiles seem inexpensive but maybe difficult to work with. Any experience with it?

 

[Rick Sykora]

Crossposting some good info on diffraction from another thread...

https://www.audiosciencereview.com/...e-kit-speaker-review.14957/page-3#post-468756

 

[Rick Sykora]

Another worthy crosspost about internal standing waves...

https://www.audiosciencereview.com/...research-x-ls-encore.14312/page-6#post-460258

 

[VeerK]

Crossposting some good info on diffraction from another thread...

https://www.audiosciencereview.com/...e-kit-speaker-review.14957/page-3#post-468756

That reflects some of my own informal findings a few years ago. IIRC, it took 3/4” roundover to really make the diffraction of a RAAL from messy to something I was quite happy with.

 

[tuga]

This is a great thread, with so many wonderful contributions and learning resources.

Based on the posts here, Reddit, and DIYAudio I was curious to get opinions on the following:

Cabinet Materials: Slate
Damped Bracing: KEF white paper
Viscoelastic material: Sorbothane or Poly 2K

Conceptually, I like how KEF opted to damp brace the back of the drivers. Has anyone tried a similar assembly as DIY? I read something from Geddes on DIYAudio a few years back and he didn’t seem to love the idea, will try to post a link. Maybe I missed it, but which poly2k brand did Geddes recommend? Sorbothane looks like a nice ready made product but I don’t know how it compares to Poly.

I’ve also been reading up on cabinet materials and I think in June someone on Reddit showed a graph where slate was more than twice as effective as MDF for reducing panel resonance. Slate tiles seem inexpensive but maybe difficult to work with. Any experience with it?

Audio Tekne uses carbon (graphite?) as cabinet, driver housing, stand and turntable plinth material.
It would be interesting to test one of their speakers for panel resonances:

http://www.audiotekne.com/en/products_sp-8716.html

 

[richard12511]

Audio Tekne uses carbon (graphite?) as cabinet, driver housing, stand and turntable plinth material.
It would be interesting to test one of their speakers for panel resonances:

http://www.audiotekne.com/en/products_sp-8716.html

The UI of that website is so outdated . Almost makes me nostalgic.

 

[Frank Dernie]

The UI of that website is so outdated . Almost makes me nostalgic.

Everything about the whole company is so outdated it...

 

[Rick Sykora]

This is a great thread, with so many wonderful contributions and learning resources.

Based on the posts here, Reddit, and DIYAudio I was curious to get opinions on the following:

Cabinet Materials: Slate
Damped Bracing: KEF white paper
Viscoelastic material: Sorbothane or Poly 2K

Conceptually, I like how KEF opted to damp brace the back of the drivers. Has anyone tried a similar assembly as DIY? I read something from Geddes on DIYAudio a few years back and he didn’t seem to love the idea, will try to post a link. Maybe I missed it, but which poly2k brand did Geddes recommend? Sorbothane looks like a nice ready made product but I don’t know how it compares to Poly.

I’ve also been reading up on cabinet materials and I think in June someone on Reddit showed a graph where slate was more than twice as effective as MDF for reducing panel resonance. Slate tiles seem inexpensive but maybe difficult to work with. Any experience with it?

Sorry, have not tried or seen anything in regard to slate.

At least a couple of us have tried some of the KEF techniques and they are discussed earlier in this thread. My result with a CLD brace behind my subwoofer driver indicated I need better CAD and/or better measurement equipment to do effectively. I have used Liquid Nails and butyl rubber as the damping layers. The driver brace idea seems like a good potential improvement, but think it needs right dampening material to be effective and not vibrate at the area of contact. My subwoofer magnet had a rubber cover and this did not seem to make a difference.

I have seen numerous folks trying to dampen panels with a variety of materials. Have yet to see any measurements or studies that proved it was worth the added weight and cost. It does seem like it should be an improvement, but a lot of folks just seem to take the "more is better" approach and do it to an extreme. If you are not bothering to do some measuring, how many braces, layers of foam. layers of sorbothane and polyfill are enough? As I talk to other designers, I hear lots of stories about too much polyfill being stuffed inside cabinets.

 

[Rick Sykora]

That reflects some of my own informal findings a few years ago. IIRC, it took 3/4” roundover to really make the diffraction of a RAAL from messy to something I was quite happy with.

Seems to be concensus for the larger roundover...

https://www.audiosciencereview.com/...nitor-with-curved-cabinets.14796/#post-468968

 

[Thomas_A]

As wished for in the GR thread effects of large bevels and wide baffle would be nice to see a simulation of.