Speaker Cabinet Design Considerations

[Deleted member 14468]

For the ultimate statement on how to design a baffle to essentially get out of the way of the drivers, you should really watch this video we just launched.

Doug Schneider
SoundStage!

 

[Rick Sykora]

For the ultimate statement on how to design a baffle to essentially get out of the way of the drivers, you should really watch this video we just launched.

Doug Schneider
SoundStage!

Was ready to toss my table saw and MDF away, but then checked Vivid’s cost of entry. The low end is the Giya G4 at $33K. It may be SOA today, but calling for the end of wooden boxes looks like it will be waiting for later day.

Maybe for when I can replace my table saw with a 3D printer and DIY a Giya.

 

[Deleted member 14468]

Was ready to toss my table saw and MDF away, but then checked Vivid’s cost of entry. The low end is the Giya G4 at $33K. It may be SOA today, but calling for the end of wooden boxes looks like it will be waiting for later day.

Hi,

They're not cheap! But that's the Giya range. Below Giya are the Kaya models, which are still pretty new. Upcoming is the S12, which is the most recent addition to the Kaya range. Was supposed to debut in May, but probably a month or two off still.

https://www.soundstageglobal.com/in...nd-mostly-inside-the-new-vivid-audio-kaya-s12

Doug
SoundStage!

 

[Rick Sykora]

Hi,

They're not cheap! But that's the Giya range. Below Giya are the Kaya models, which are still pretty new. Upcoming is the S12, which is the most recent addition to the Kaya range. Was supposed to debut in May, but probably a month or two off still.

https://www.soundstageglobal.com/in...nd-mostly-inside-the-new-vivid-audio-kaya-s12

Doug
SoundStage!

Thanks Doug!

Got my Giya's and Kaya's mixed up, so the real current cost of entry is ~$10K US (converted from pounds). Vivid says it is for small rooms and they are passive rather active (they all appear to be passive).

Still is a great story and look forward to the day when Amir gets one to test!

 

[Deleted member 14468]

Got my Giya's and Kaya's mixed up, so the real current cost of entry is ~$10K US (converted from pounds). Vivid says it is for small rooms and they are passive rather active.

There's no question that a lot of this stuff is VERY expensive. Not affordable for most people. It's what happens with boutique-type manufacturing.

Doug
SoundStage!

 

[Rick Sykora]

Since this got posted on another thread first, it is a great interview if you are interested, otherwise forward to around 32 mins in for the most pertinent part for this thread.

 

[Deleted member 14468]

Hi,

I would say that one of the most important parts is at 12:56 - it's where I bring up the B&W Matrix 1 to have Laurence Dickie talk about the Matrix enclosure technology, which was B&W's largest- and longest-lasting attempt at reducing cabinet resonances. It's really critical to the work Dickie did after.

Doug

 

[Rick Sykora]

Hi,

I would say that one of the most important parts is at 12:56 - it's where I bring up the B&W Matrix 1 to have Laurence Dickie talk about the Matrix enclosure technology, which was B&W's largest- and longest-lasting attempt at reducing cabinet resonances. It's really critical to the work Dickie did after.

Doug

Good point, but would be surprised if the readers of this thread were unaware of b&w matrix cabinet design.

 

[GelbeMusik]

Not affordable for most people.

Hi Doug,

I looked up some speaker review of Yours on "Sounstage!". Good writing, no irony. It comes out very clearly, what You feel about the product. For instance You perform the "knuckle test" on enclosure walls. I know from personal experience how much it can hurt. But to be quite honest, the "knuckle test" is ill advised not only from a medical standpoint. You may recollect Your knowledge from the engineering class. To knock the enclosure doesn't tell anything about the walls motion in case it is pushed from the air inside, or to some minor degree from back-forces from the speaker cone.

For all the others, without engineering knowledge: it is always said (but wrong) that planar speakers are driven nearly equally over all of the surface. Hence no breakup modes are to be expected. Same should be true with walls driven by the air pressure inside an enclosure. Expect just a single basic non-resonant motion of no further interest.
If it wasn't the air to drive the wall, where is the point that drives the wall into the imaginated motion? For sure not where the wall hits the knuckle. Hence, different patterns, hence different sound / volume is to be expected from real operation as compared to the musical knuckle.

I refer to this one:
https://www.soundstagehifi.com/index.php/equipment-reviews/1399-magico-a1-loudspeakers

Me thinks it is in order to bring the interview into some perspective. You refrain from bothering people with measurements. Instead friendly advice is given on power cords christened "Shunyata Research Venom HC" or "EMM Labs Pre" which underline the scientific approach to "Nirvana Audio S-L, QED XT25". As I commented in the other thread, such product brings back some magic to the business. I think this is fair to those who are able to deliberately buy.

 

[Deleted member 14468]

Hi,

Many of your readers are obviously very knowledgeable, but I've also found that people who got into the hobby in, say, the last 10 or 20 years are often quite unaware of the developments in the 80s and before that. Even Dickie comments about designers who don't seem to have the knowledge of work done decades before him.

There's also a history lesson there. Before I met him several years ago, I never knew how the inspiration for the Matrix began. And even before this interview, I had no idea that B&W was kind of envious of Celestion's work with Aerolam. Also, that picture of the wooden prototype Nautilus -- had Jake Purches not sent me that after the interview, I would've had no idea.

Doug

 

[tuga]

The BBC approach (cabinet design from 11:41):

 

[Frank Dernie]

Seems a bit messy, but might be useful to try for a speaker as a way to visualize cabinet resonances. Suspect part of the issue is how to suspend the speaker to minimize any contact points that might affect the modes?

I did this about 40 years ago using a frequency generator and the speaker drivers as exciters, for obvious reasons, and looking at the various modes. I used sand and indeed the support makes a huge difference to the mode shapes as one would predict.
Mounting the speaker on lossy pads near the antinode of one mode suppresses it delightfully
These were early days for me, a KEFkit 3 in a chipboard box and the panel vibration felt to the finger tips non-negligible compared to the driver vibration and on a much bigger surface area.
That interest is part of why I became a noise and vibration R&D engineer as my first job.
Speaker cabinets have interested me ever since.

 

[GelbeMusik]

I did this about 40 years ago using a frequency generator and the speaker drivers as exciters, for obvious reasons, and looking at the various modes. I used sand and indeed the support makes a huge difference to the mode shapes as one would predict.

I never (!) saw a "mode" in a panels motion, which should be an-harmonic. The panels motion always (!) reflected, if at all, harmonic (1, 2, 3 …)modes of air resonance inside the enclosure. That is a huge difference in understanding the topic. I have to admit that quite basic considerations regarding stiffness were taken into account. E/g the walls thickness was left to be 12mm for practical purposes, as to provide some area for (sloppy) glue-joints and so on.

Today we have laser scanners and the mathematical tool of boundary layer analysis. Once You use it, it contradicts the work model of e/g the BBCs investigations, which addressed the panel alone. Comes out: non-issue, with halfway reasonable construction.

I already advertised to build a vibrometer yourselves. From a cheap and readily available electret microphone. Nobody asked back … If You build two, You could easily investigate phase for instance, as to detect--or not--differential "modes". Why is it, that everybody likes to speculate on imaginations, driving useless effort to stellar heights, while a simple device is handy in order to catch a glimpse onto the real world instead.

Consider it to be the same as with a microphone. Would You actually dare to work on a crossover without? Why do You do so for an "optimized" cabinet?

Regarding shape, this works pretty nice, and doesn't cost a leg and an arm, marriage, kids, house, dog:

https://heissmann-acoustics.de/disco-m/

 

[Frank Dernie]

I never (!) saw a "mode" in a panels motion, which should be an-harmonic. The panels motion always (!) reflected, if at all, harmonic (1, 2, 3 …)modes of air resonance inside the enclosure. That is a huge difference in understanding the topic. I have to admit that quite basic considerations regarding stiffness were taken into account. E/g the walls thickness was left to be 12mm for practical purposes, as to provide some area for (sloppy) glue-joints and so on.

Today we have laser scanners and the mathematical tool of boundary layer analysis. Once You use it, it contradicts the work model of e/g the BBCs investigations, which addressed the panel alone. Comes out: non-issue, with halfway reasonable construction.

I already advertised to build a vibrometer yourselves. From a cheap and readily available electret microphone. Nobody asked back … If You build two, You could easily investigate phase for instance, as to detect--or not--differential "modes". Why is it, that everybody likes to speculate on imaginations, driving useless effort to stellar heights, while a simple device is handy in order to catch a glimpse onto the real world instead.

Consider it to be the same as with a microphone. Would You actually dare to work on a crossover without? Why do You do so for an "optimized" cabinet?

Regarding shape, this works pretty nice, and doesn't cost a leg and an arm, marriage, kids, house, dog:

https://heissmann-acoustics.de/disco-m/

I am a simple man.
I used the drivers as the excitation, as I wrote, for obvious reasons, they actually are the excitation in use.
I had a colleague using laser vibrometer in the early days, 1975ish iirc, which was a very useful tool but I went into a different career in 1976.
I do know engineers who use fe and laser measurements to design loudspeakers but have had nothing to do with it, other than interest, for over 40 years.
Are you an engineer using these design tools?
In general I don't agree with you and personally believe you are sometimes drawing wrong conclusions from data.
So I would not be buying a speaker you designed, with all due respect.

 

[GelbeMusik]

Are you an engineer using these design tools?

I use, as a hobbyist, those mentioned retrofitted electrets. I don't build for money anymore. So I'm free to do it right, independent from hyperbole in irrelevant areas. I like to investigate physical phenomena for no good reason, which, by profession is a lived-in comfort zone to me. If once in a while You detect a more conceptual approach, You get it just right.

 

[tuga]

 

[Deleted member 14468]

Regarding the Rockport Lyra, we produced a video that goes quite deep into its construction. Enjoy!

Doug Schneider
SoundStage!

 

[maty]

Viscoelastic material

https://en.wikipedia.org/wiki/Viscoelasticity

• https://www.audiosciencereview.com/.../3134809/&q=viscoelastic+material&o=relevance
• https://www.google.com/search?q=diyaudio.com+viscoelastic+material+maty

 

[richard12511]

Regarding the Rockport Lyra, we produced a video that goes quite deep into its construction. Enjoy!

Doug Schneider
SoundStage!

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?

 

[Frank Dernie]

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?

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.