French Speakers

[fmw]

Tweeters don't move enough air to have enclosure resonances become an important factor in performance. Resonances increase as the drivers get larger simply because the larger drivers move more air.

 

[stratman]

The only decent French speakers that I've auditioned have been Cabasse. They were excellent, apart from these I haven't heard anything extraordinary from the Frogs.

Cabasse.com

 

[avaserfi]

I notice that Stereophile only measures cabinet resonance up to 2kHz, is typical cabinet construction sufficient to deal with resonances above the point of upper midrange to lower treble, or is there simply insufficient energy at higher frequencies to excite any cabinet resonances? If this topic is dealt with in the AES papers you mentioned, I apologies for seeming lazy, I just don't want to spend $40 right now.

I did a little poking around on Stereophile's site perhaps this would answer your question. Check out page 6 "Panel Vibrational Behavior" near the end and it goes on to page 7. I figured their reasoning would be better than mine for the question asked .

 

[annunaki]

Speaker design and manufacture hasn't changed meaningfully in 50 years. The well-designed speakers of today sound about like the well-designed speakers of 50 years ago and are designed around the same formulae.

I would not say that. Not at all. Motor and suspension linearity have improved greatly on speakers in even the last 5-10 yrs. Even "cheap" speakers sound fairly decent today. That long ago speaker design was more of a guessing game. With the advent of computer modeling, testing, simulation and more we have a much better understanding of the dynamic loudspeaker. In the last 5-10 years we have gotten a much firmer grasp on how they behave while moving.

While it is true that the general design of the moving coil speaker has not changed much, to say they are similar in sound to speakers from 50 yrs. ago is a bit stretched.

 

[no. 5]

Tweeters don't move enough air to have enclosure resonances become an important factor in performance. Resonances increase as the drivers get larger simply because the larger drivers move more air.

That's what I was thinking, that there isn't enough produced energy at high frequencies to produce a resonance in the cabinet, but I wanted verification.

I did a little poking around on Stereophile's site perhaps this would answer your question. Check out page 6 "Panel Vibrational Behavior" near the end and it goes on to page 7. I figured their reasoning would be better than mine for the question asked .

It does help, thank you.

 

[annunaki]

Those speakers may sound better than one thinks. They are using an aperiodic enclosure for the drivers which will allow for minimal cabinet resonances. They just name it differently: Acoustic Damping Tube. I have not seen these in quite awhile.

An Aperiodic enclosure utilizes very small enclosure directly around the woofer but has a "breathable membrane" affixed to the rear of the "Damping tube". This allows the speaker to interact with the air in the enclosure to lower it's frequency response. This is the first time I have seen them used in a home audio application. They tend to be quite accurate and play fairly deep. The way the glass is utilized here the resonance issue may not be as bad as some think. If the Aperiodic membrane enclosure is constructed properly the resonance factor can be kept very low.

Are their easier ways to arrive at the same result, hell yes. However, I have to give it to them for being innovative and doing it about as right as you can with a glass enclosure.

They (aperiodic enclosures) have been used in car audio applications with great success. Just ask Earl Zausmer with his BMW utilizing B&W 801's for the front stage. The 15" drivers used Aperiodic enclosures in the floor to allow their size and used the air outside the vehicle to lower the response. I believe he has multiple IASCA world titles for soundquality competitions.

 

[Joe Schmoe]

Even "cheap" speakers sound fairly decent today.

Oh, definitely. In fact, I would call that a major understatement. I have heard speakers for a couple of hundred that sound great, and speakers around $1000/pr so good I have no reason to ever spend more than that. In addition, the performance/price ratio is constantly improving. I recently picked up a pair of Mirages for $140 that I could easily be happy with as my primary speakers, something I could not have said about any speakers for that price even 4 or 5 years ago.

 

[jcPanny]

"See Through" Speakers

If your friend does not want to see the speakers have him get some high end in-wall speakers from Triad, Speakercraft, etc.

 

[WmAx]

Those speakers may sound better than one thinks. They are using an aperiodic enclosure for the drivers which will allow for minimal cabinet resonances. They just name it differently: Acoustic Damping Tube. I have not seen these in quite awhile.

It is not clear to me what you mean. If you mean the aperiodic vent will dampen the driver-air volume system spring, then yes, this is correct. If you mean it will dampen physical cabinet panel vibrations, this is not correct.

-Chris

 

[fmw]

I would not say that. Not at all. Motor and suspension linearity have improved greatly on speakers in even the last 5-10 yrs. Even "cheap" speakers sound fairly decent today. That long ago speaker design was more of a guessing game. With the advent of computer modeling, testing, simulation and more we have a much better understanding of the dynamic loudspeaker. In the last 5-10 years we have gotten a much firmer grasp on how they behave while moving.

While it is true that the general design of the moving coil speaker has not changed much, to say they are similar in sound to speakers from 50 yrs. ago is a bit stretched.

Better go do some listening tests if you can find any of the oldies. I think you would be surprised how a 50 year old Klipschorn or Altec A3 or Bozak Symphony sounded. I don't doubt the science of speaker design is more sophisticated today. Certainly we don't have foam surrounds that rot after a decade or two. But the sound really is about the same. So are the measurements to back that up.

I can't think of another product category in the electronics field that has had less technological innovation than loudspeakers unless it is VHF television antennas.

You can say the same thing about audio amplifiers which have about the same measurements and performance they've had for several decades. Inaudible distortion and flat frequency responses are still the same. Yes, they use op amps instead of discreet circuits but the measurements and performance are roughly the same.

 

[annunaki]

It is not clear to me what you mean. If you mean the aperiodic vent will dampen the driver-air volume system spring, then yes, this is correct. If you mean it will dampen physical cabinet panel vibrations, this is not correct.

-Chris

Chris,

It is to my understaning that there would be substantially less acoustic energy transmitted to the air space within the cabinet. This is not to say that there is still no possiblity for resonances, just that they would be substantially subdued. Using a dense material such as glass would help to lower resonances as well. I am sure there would still be some present pehaps some audible but it is a creative solution regarding the enclosure type none the less.

It is to my understanding that the aperiodic enclosure around the drivers is also decoupled from the glass enclosure as well.

The aperiodic systems tend to act like large sealed systems (as I am sure you are aware).

 

[annunaki]

So you are saying that one of those speakers would compare evenly (objectively and subjectively) with the likes of say a B&W 802D in terms of linearity and total lack of resonance coloration?

I am not doubting that there were good sounding speakers back then. However, they will still fall behind in terms of dynamic linearity and resonance as that is where the greatest strides have been made in driver and enclosure design.

Better go do some listening tests if you can find any of the oldies. I think you would be surprised how a 50 year old Klipschorn or Altec A3 or Bozak Symphony sounded. I don't doubt the science of speaker design is more sophisticated today. Certainly we don't have foam surrounds that rot after a decade or two. But the sound really is about the same. So are the measurements to back that up.

I can't think of another product category in the electronics field that has had less technological innovation than loudspeakers unless it is VHF television antennas.

You can say the same thing about audio amplifiers which have about the same measurements and performance they've had for several decades. Inaudible distortion and flat frequency responses are still the same. Yes, they use op amps instead of discreet circuits but the measurements and performance are roughly the same.

 

[WmAx]

Chris,

It is to my understaning that there would be substantially less acoustic energy transmitted to the air space within the cabinet. This is not to say that there is still no possiblity for resonances, just that they would be substantially subdued. Using a dense material such as glass would help to lower resonances as well. I am sure there would still be some present pehaps some audible but it is a creative solution regarding the enclosure type none the less.

Unfortunately, this would not appear to be true. The only thing dampened by any substantial degree is the tuned box resonance. Even if you filled the enclosure 100 percent with fiberglass, the absorption material alone can not rid substantial energy before it impedes upon the wall surface. Transmission is not the same as absorption. A dampening material works to absorb energy in complex physical interaction that involves both it and a barrier behind it. While the reflection of acoustic energy may be nearly non-existent, it was substantial when it passed through the dampening material and into the impeding wall behind it. Stereophile is useful in some cases. In this, it is interesting in that it has in it's archive, panel resonances amplitude measurements from centralized points on the cabinets of two TL speaker systems(PMC IB-1S and MeadowLark Swift). The panel resonance amplitude is no different than would be expected from a standard cabinet system with moderate bracing. TL systems use a fully stuffed enclosure and a substantial pressure relief device in the form of that TL opening - yet doing such does not seem to yield any substantial reduction in wall resonance.

It is to my understanding that the aperiodic enclosure around the drivers is also decoupled from the glass enclosure as well.

I am not sure as to what you mean. Glass enclosure? Did I miss something?

Addendum by WmAx: I did not actually read the links to the French speakers at issue here before now. I now realize what you mean by glass enclosures. That is a terrible speaker design. No internal damping material. Free reflections internally. Even if it had non resonant walls -- which there is no evidence to support such a suspicion - the lack of internal acoustic dampening would doom it to resonance/low-fidelity.

-Chris

 

[annunaki]

Unfortunately, this would not appear to be true. The only thing dampened by any substantial degree is the tuned box resonance. Even if you filled the enclosure 100 percent with fiberglass, the absorption material alone can not rid substantial energy before it impedes upon the wall surface. Transmission is not the same as absorption. A dampening material works to absorb energy in complex physical interaction that involves both it and a barrier behind it. While the reflection of acoustic energy may be nearly non-existent, it was substantial when it passed through the dampening material and into the impeding wall behind it. Stereophile is useful in some cases. In this, it is interesting in that it has in it's archive, panel resonances amplitude measurements from centralized points on the cabinets of two TL speaker systems(PMC IB-1S and MeadowLark Swift). The panel resonance amplitude is no different than would be expected from a standard cabinet system with moderate bracing. TL systems use a fully stuffed enclosure and a substantial pressure relief device in the form of that TL opening - yet doing such does not seem to yield any substantial reduction in wall resonance.


I am not sure as to what you mean. Glass enclosure? Did I miss something?

Addendum by WmAx: I did not actually read the links to the French speakers at issue here before now. I now realize what you mean by glass enclosures. That is a terrible speaker design. No internal damping material. Free reflections internally. Even if it had non resonant walls -- which there is no evidence to support such a suspicion - the lack of internal acoustic dampening would doom it to resonance/low-fidelity.

-Chris

Chris,

As I am sure you are aware, aperiodic enclosures only use the extra "air" in the glass enclosure to lower frequency response in the bass regions. The actual enclosure is the "Acoustic Damping Tube" (aperiodic enclosure) as they call it. Assuming that this Active Daming Tube (aperiodic enclosure) is resonance free and decoupled from the glass I do not see how the actual glass box will make significant difference as it will not be under much pressure at all. Seeing that the woofer really only needs to 'breathe" (i.e. access the air in the glass box) through the aperiodic membrance at low frequencies (below 500hz or so) I don't see resonance as being as big of an issue as it would be with a driver using the glass box as the actual enclosure without an aperiodic enclosure behind the woofer.

 

[TLS Guy]

That speaker is a very complex conundrum. However, I suspect there will be leak of higher frequencies through any membrane that would allow the drivers to couple to the box. The question also arises as to what are the Thiel/Small parameters of the the driver plus the sub enclosure and membrane. There have to be resonances there. How to these interact with the glass case? Without seeing the math it is hard to comment.

As to enclosure material, density is not the only parameter. The Young's modulus is very important. Ted Jordan did some work on this, and I know that glass had a Young's modulus that was very unfavorable. Steel is very dense, but it would be about the worst material possible for a speaker.

I certainly would not purchase those speakers without extended listening. The French have made some good speakers, but a lot more than their fair share of very bad ones.

It's a bit like the French drug formularies, everything up the a**

 

[WmAx]

Chris,

As I am sure you are aware, aperiodic enclosures only use the extra "air" in the glass enclosure to lower frequency response in the bass regions. The actual enclosure is the "Acoustic Damping Tube" (aperiodic enclosure) as they call it. Assuming that this Active Daming Tube (aperiodic enclosure) is resonance free and decoupled from the glass I do not see how the actual glass box will make significant difference as it will not be under much pressure at all. Seeing that the woofer really only needs to 'breathe" (i.e. access the air in the glass box) through the aperiodic membrance at low frequencies (below 500hz or so) I don't see resonance as being as big of an issue as it would be with a driver using the glass box as the actual enclosure without an aperiodic enclosure behind the woofer.

I did not realize the drivers were contained in mini 'sub-enclosures'. This is an odd speaker.

-Chris

 

[Soundman]

I'm hearing a lot of technical opinions on these speakers, but has anyone heard them? That's all I care about. HOW DO THEY SOUND?

 

[naisphoo]

I would not even buy those glass speakers for $800/pair.

keep dreaming man...they don't want to sell them for $800/pair...the price is $5400/pair...so you see...can't afford them then don't badmouth them...every comments from all the audioalcoholics experts on this thread about those speakers is pure speculation...nobody has seen them in person let alone heard them...so why taking a such harsh stance?

 

[naisphoo]

That speaker is a very complex conundrum. However, I suspect there will be leak of higher frequencies through any membrane that would allow the drivers to couple to the box. The question also arises as to what are the Thiel/Small parameters of the the driver plus the sub enclosure and membrane. There have to be resonances there. How to these interact with the glass case? Without seeing the math it is hard to comment.

As to enclosure material, density is not the only parameter. The Young's modulus is very important. Ted Jordan did some work on this, and I know that glass had a Young's modulus that was very unfavorable. Steel is very dense, but it would be about the worst material possible for a speaker.

I certainly would not purchase those speakers without extended listening. The French have made some good speakers, but a lot more than their fair share of very bad ones.

It's a bit like the French drug formularies, everything up the a**

i'm french and no nothing is up the ***...as you claimed. you don't know much about the French do you?

 

[Twexcom]

Those links no longer work.