box around ESL

[justice strike]

Normal speakers are often used in combination with a box to change some of te characteristics of the sound. However the open baffle design has also had some success .

I'm curious to know if someone has actually tried enclosing one site of a esl speaker in a box to do actually the same as with a normal driver. Has anyone tried this? I can't find any examples of such an ESL speaker.

[frank ziel]

If you look here, you'll find such a successful attempt:
http://www.beveridge-audio.com/products.html#The_G-3
but...
I do not see any point, why someone want to have
sound coloration from a box.

[Calvin]

Hi,

Magnepan´s advertisements once spoke out one of the great audio truths:
"Music doesn´t live in boxes!"

jauu
Calvin

[Jakob2]

Back in the 80´s was a project realized for CD-production monitoring.

The description was given in an AES paper:

http://www.aes.org/e-lib/browse.cfm?elib=10244

They used a couple of matsushita ribbon tweeters, a Quad ESL63 as a midrange unit in a closed box and 3 15inch woofers.

If you can´t reach the AES paper, some informations were available on a german website (unfortunately only in german):

http://www.top-audio.de/taweb/speake...v/ch-2/ch2.htm

[arend-jan]

A closed box only makes sense for the bass, but an electrostatic driver has a much weaker motor and much less moving mass than a electromagnetic driver. As a result the response at low frequencies will be dominated by the stiffness of the air in the box and the resonance frequency is pushed up. This gives a rather poor performance (read low output power) and the fact is that more output is available when the ESL is used without a box.

Add to that all the disadvantages that you get from an enclosure and it start to make sense that electrostatic speakers are the way they are.

What would be very interesting is to put an ESL in the wall with plenty of space behind it. That could make a phenomenal bass performance.

Magnetostats have a more powerful motor so it could be feasible to put those in a box.

[a.wayne]

Originally Posted by frank ziel

If you look here, you'll find such a successful attempt:
http://www.beveridge-audio.com/products.html#The_G-3
but...
I do not see any point, why someone want to have
sound coloration from a box.

Hello Frank ,

I think you should listen to the Beveridge before discarding and panels do have there own flavor of coloration ..

[justice strike]

Originally Posted by arend-jan

A closed box only makes sense for the bass, but an electrostatic driver has a much weaker motor and much less moving mass than a electromagnetic driver. As a result the response at low frequencies will be dominated by the stiffness of the air in the box and the resonance frequency is pushed up. This gives a rather poor performance (read low output power) and the fact is that more output is available when the ESL is used without a box.

true, but the same holds for normal speakers. And yes, enclosing it in the wall would make performance better, but this also holds for normal speakers.

[Calvin]

Hi,

besides the problem of vastly increasing Fs with a ´typical´ box there´s the issue of reflections within the box. Many boxes are built like a backpack to a dynamic driver and it seems that most people think that the membrane of the driver is a ´isolation barrier´ for the internal reflected sound energy. But it is not. It´s just an optical barrier. The reflected sound migrating through the membrane is of considerable amplitude and consists of early reflections. It´s to my experience one reason of the less clean and smeared sound of dynamic driver boxes and clearly deceptable in the midrange.
But while the membrane of a dynamic driver features at least a bit of damping an ESL-diaphragm is virtually acoustically non-existant. What goes into the box comes out of the box nearly unaltered, apart from a bit of damping by the internal stuffing. But this stuffing is effective only at higher frequencies and without effect in the bass region. As a consequence a suggested compartement for ESLs should be different to one for a dynamic driver. Mr. Walker gave the idea of a very deep and tapered dampened compartement. To dampen the fundamental resonance he suggested an open style cabinet (kind of BR-Type). The idea was to design a compartment that does not reflect any sound wave back to and through the membrane. Enclosing the panel into a wall only improved the sound if those ideas were followed.

jauu
Calvin

[arend-jan]

Originally Posted by justice strike

true, but the same holds for normal speakers.

I get the impression that you don't completely understand what I'm saying.

But let me turn the question around.
What do expect to gain by putting an ESL in a box?

[a.wayne]

Originally Posted by Calvin

Hi,

besides the problem of vastly increasing Fs with a ´typical´ box there´s the issue of reflections within the box. Many boxes are built like a backpack to a dynamic driver and it seems that most people think that the membrane of the driver is a ´isolation barrier´ for the internal reflected sound energy. But it is not. It´s just an optical barrier. The reflected sound migrating through the membrane is of considerable amplitude and consists of early reflections. It´s to my experience one reason of the less clean and smeared sound of dynamic driver boxes and clearly deceptable in the midrange.

Hello Calvin,

This is true and requires a chamber designed and dampened to deal with 1. Reflections and 2. Driver dynamic compression ...

A properly designed "Box" will not exhibit the deficiencies you have listed in the midrange and while they might lack "panel speaker openness" this is mostly due to there Polar Pattern more so than just being in a Box. Hence you trade some accuracy for openness with Panel speakers .

Originally Posted by Calvin

But while the membrane of a dynamic driver features at least a bit of damping an ESL-diaphragm is virtually acoustically non-existant. What goes into the box comes out of the box nearly unaltered, apart from a bit of damping by the internal stuffing. But this stuffing is effective only at higher frequencies and without effect in the bass region. As a consequence a suggested compartement for ESLs should be different to one for a dynamic driver. Mr. Walker gave the idea of a very deep and tapered dampened compartement. To dampen the fundamental resonance he suggested an open style cabinet (kind of BR-Type). The idea was to design a compartment that does not reflect any sound wave back to and through the membrane. Enclosing the panel into a wall only improved the sound if those ideas were followed.

jauu
Calvin

The Beveridge cabinet design seems to address much of the above and hence , requires a listen to before condemnation ..

Putting any speaker into a wall will give it attenuation , but very little reward anywhere else as the boundary effect and reflections will lower the quality of the sound . I would not recommend this if for Hi-Fi listening ..

regards,