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Ed Presson[_2_] Ed Presson[_2_] is offline
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Default Electrostatics, anyone?

My first good stereo speakers were the original Quad Electrostatic
Loudspeakers. I thought they were remarkable,
despite the lack of any really deep bass and some rolled-off highs. On
voice, they are the only speakers that ever
made me jump thinking someone else was in the room.

About a decade later, I splurged on a double-pair of KLH-9s. Better in
some, but not all, ways.

Over the years, I heard Acoustat, Koss, Beveridge (sp?), Sound Lab ESLs, and
more recent Quad models.
The original Martin-Logan CLS created an amazing holographic image, but
totally transparent-but without bass
or a palpable sense of acoustic power heard in a good concert hall.

All of these ESLs, seemed to me to have a limited dynamic range and lose
their transparency when pushed by large
orchestral works. Nonetheless, I was always attracted to certain ESL
characteristics and remain so, even though
I now have Infinity speakers with EMIT and EMIM drivers.

Is Martin-Logan the ESL manufacturer left standing? Has anyone heard (or
heard of) and ESL that finally
minimized the limits I described above?

Ed Presson


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Peter Wieck Peter Wieck is offline
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Default Electrostatics, anyone?

For a number of years, I kept Acoustat speakers along with a pair of AR11s.=
Then I heard a pair of AR9s, and the 11s went away, the Acoustats went to =
my brother who has them to this day.=20

We moved into a house with no room for the 9s, they were replaced by a pair=
of M5s. Then we moved into a house with a 27 x 17 x 10 library at about th=
e same time I heard a pair of Magnepans. That was 9 years ago this month.=
=20

Today, the main system is a pair of MG-IIIs with the ribbon tweeter and the=
external crossovers. I will never look back. If you like the soundstage fr=
om planar speakers, but do not like the rolled off top and bottom, look int=
o Maggies. No sub-woofer needed. No, they do not have the bass of an AR9, b=
ut they can shake the room. The highs, on the other hand, are unsurpassed. =
Still made in the USA. By the way, the Acoustats sound thin by comparison.=
=20

Fair Warning: They are power-pigs, even more so than my pair of AR3as.=20

Peter Wieck
Melrose Park, PA=20
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Greg Berchin[_4_] Greg Berchin[_4_] is offline
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Default Electrostatics, anyone?

On 4 Mar 2017 12:15:28 GMT, "Ed Presson" wrote:

All of these ESLs, seemed to me to have a limited dynamic range and lose
their transparency when pushed by large
orchestral works.


I have always wondered whether this seemingly universal impression of
electrostatics has been caused by their being driven improperly.
Conventional wisdom is that electrostatics are voltage-driven devices,
but strict application of Gauss' and Coulomb's Laws indicates that they
are actually charge-driven. When driven by voltage, the force on the
diaphragm changes as excursion changes. When driven by charge, the force
is independent of excursion.
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abbeynormal abbeynormal is offline
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Default Electrostatics, anyone?

I have not heard any speakers that impressed me more than a [1982] pair of =
Maggie tympani IIIs [driven by giant monoblock class A's each the size of a=
small refrigerator and as efficient at heating the room as a fireplace] th=
at utterly transported me to the cathedral in a good direct-disk pipe organ=
recording.
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abbeynormal abbeynormal is offline
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Default Electrostatics, anyone?

On Saturday, March 4, 2017 at 5:24:46 AM UTC-8, Greg Berchin wrote:
On 4 Mar 2017 12:15:28 GMT, "Ed Presson" wrote:

All of these ESLs, seemed to me to have a limited dynamic range and lose
their transparency when pushed by large
orchestral works.


I have always wondered whether this seemingly universal impression of
electrostatics has been caused by their being driven improperly.
Conventional wisdom is that electrostatics are voltage-driven devices,
but strict application of Gauss' and Coulomb's Laws indicates that they
are actually charge-driven. When driven by voltage, the force on the
diaphragm changes as excursion changes. When driven by charge, the force
is independent of excursion.


can you tell me your impression of what electrostats would sound like if somehow they were driven differently?


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Peter Wieck Peter Wieck is offline
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Default Electrostatics, anyone?

On Sunday, March 5, 2017 at 7:36:25 AM UTC-5, abbeynormal wrote:
I have not heard any speakers that impressed me more than a [1982] pair o=

f Maggie tympani IIIs [driven by giant monoblock class A's each the size of=
a small refrigerator and as efficient at heating the room as a fireplace] =
that utterly transported me to the cathedral in a good direct-disk pipe org=
an recording.

There is that. I often wonder why those who have the space do not simply go=
to Maggies and have done with it. Even new, they are certainly reasonably =
priced, are entirely remarkable and in my direct experience, very rugged.=
=20

http://www.integracoustics.com/MUG/M.../speakers.html =20

Is a link not quite to the beginning of time, but close and far enough. The=
specifications given are very conservative, again in my direct experience.

Peter Wieck
Melrose Park, PA
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Greg Berchin[_4_] Greg Berchin[_4_] is offline
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Default Electrostatics, anyone?

On 6 Mar 2017 12:56:47 GMT, abbeynormal wrote:

can you tell me your impression of what electrostats would sound like if somehow they were driven differently?


Beats me. I have found that trying to predict how something will sound by
analyzing the math alone generally doesn't work very well.

I can say this, though. High school physics tells us that, when driven by
voltage, the force on the diaphragm is:

(Vbias+Vaudio)^2 (Vbias-Vaudio)^2
F = e0A--------------------- - e0A---------------------,
2[(|dFR|/2)-deltaD]^2 2[(|dFR|/2)+deltaD]^2

where e0 = the permittivity of free space
A = the area of the diaphragm
Vbias = the bias voltage applied to the stators
Vaudio = the audio signal voltage
|dFR| = the distance (gap) between the front and rear stators
deltaD = how far the diaphragm has moved from its center rest position

Note that the force changes as deltaD changes, i.e., when the diaphragm moves
closer to one of the stators and farther from the other, even when Vbias and
Vaudio are held constant.

But when driven by charge, the force on the diaphragm is:

|qbias*qaudio|
|F| = 2--------------
e0A

where qbias = the bias charge applied to the stators
qaudio = the charge applied by the audio signal
and the direction of the force can be determined by context.

Note that the force is constant as long as the charges are constant, regardless
of the position of the diaphragm.

Now, how do we design a charge amplifier? In theory, it's not all that
difficult. Hint: electrostatic loudspeakers are capacitors, capacitors store
charge, and current integrated over time equals charge.
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isw isw is offline
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Default Electrostatics, anyone?

In article ,
Greg Berchin wrote:

On 6 Mar 2017 12:56:47 GMT, abbeynormal wrote:

can you tell me your impression of what electrostats would sound like if
somehow they were driven differently?


Beats me. I have found that trying to predict how something will sound by
analyzing the math alone generally doesn't work very well.

I can say this, though. High school physics tells us that, when driven by
voltage, the force on the diaphragm is:

(Vbias+Vaudio)^2 (Vbias-Vaudio)^2
F = e0A--------------------- - e0A---------------------,
2[(|dFR|/2)-deltaD]^2 2[(|dFR|/2)+deltaD]^2

where e0 = the permittivity of free space
A = the area of the diaphragm
Vbias = the bias voltage applied to the stators
Vaudio = the audio signal voltage
|dFR| = the distance (gap) between the front and rear stators
deltaD = how far the diaphragm has moved from its center rest position

Note that the force changes as deltaD changes, i.e., when the diaphragm moves
closer to one of the stators and farther from the other, even when Vbias and
Vaudio are held constant.

But when driven by charge, the force on the diaphragm is:

|qbias*qaudio|
|F| = 2--------------
e0A

where qbias = the bias charge applied to the stators
qaudio = the charge applied by the audio signal
and the direction of the force can be determined by context.

Note that the force is constant as long as the charges are constant,
regardless
of the position of the diaphragm.

Now, how do we design a charge amplifier? In theory, it's not all that
difficult. Hint: electrostatic loudspeakers are capacitors, capacitors store
charge, and current integrated over time equals charge.


Some electrostatic speakers use a material with extremely high surface
restivity for the diaphragm (made e.g. by lightly rubbing the plastic
sheet with a carbon-dust-coated pad). The claim is that doing it that
way puts the diaphragm in a "constant charge" mode (IIRC).

Isaac
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Greg Berchin[_4_] Greg Berchin[_4_] is offline
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Default Electrostatics, anyone?

On 7 Mar 2017 11:35:57 GMT, isw wrote:

Some electrostatic speakers use a material with extremely high surface
restivity for the diaphragm (made e.g. by lightly rubbing the plastic
sheet with a carbon-dust-coated pad). The claim is that doing it that
way puts the diaphragm in a "constant charge" mode (IIRC).


Yes, I have heard that. But why approximate it when you can achieve it
explicitly through design?
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isw isw is offline
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Default Electrostatics, anyone?

In article ,
Greg Berchin wrote:

On 7 Mar 2017 11:35:57 GMT, isw wrote:

Some electrostatic speakers use a material with extremely high surface
restivity for the diaphragm (made e.g. by lightly rubbing the plastic
sheet with a carbon-dust-coated pad). The claim is that doing it that
way puts the diaphragm in a "constant charge" mode (IIRC).


Yes, I have heard that. But why approximate it when you can achieve it
explicitly through design?


I suppose there could be some advantage to using standard off-the-shelf
amplifiers.

Isaac


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Greg Berchin[_4_] Greg Berchin[_4_] is offline
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Default Electrostatics, anyone?

On 8 Mar 2017 09:44:50 GMT, isw wrote:

I suppose there could be some advantage to using standard off-the-shelf
amplifiers.


Perhaps. But audiophiles are often willing to go to great lengths for the
ultimate in sound quality. Why compromise here?
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Peter Wieck Peter Wieck is offline
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Default Electrostatics, anyone?

On Saturday, March 11, 2017 at 8:20:12 AM UTC-5, Greg Berchin wrote:

Perhaps. But audiophiles are often willing to go to great lengths for the
ultimate in sound quality. Why compromise here?


I might argue with the last six letters after Audio - but that is neither h=
ere nor there. What is relevant (in my opinion) is limiting technology vs. =
open technology. If I manufacture a speaker that is open to many sorts of d=
river (amplifiers), I am enabling my customers to make choices that *includ=
e* my speaker without *excluding* the customer's existing equipment. So, I =
am opening options to that customer.=20

In any case, when I heard my first pair of planar speakers (Accoustat), I w=
as impressed enough to consider them as compared to AR 11s. But, when I hea=
rd my first pair of Maggies, that was that. My brother has those Accoustats=
in a small room with good proportions, and they do exceedingly well. That =
room is the size of my hobby room today. The Maggies FILL a room that is 17=
x 26 x 10. Yes, I have a brute-force amp driving them, but it could be any=
-of-several.

Peter Wieck
Melrose Park, PA=20

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Ed Presson[_2_] Ed Presson[_2_] is offline
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Default Electrostatics, anyone?

"Peter Wieck" wrote in message ...

On Saturday, March 11, 2017 at 8:20:12 AM UTC-5, Greg Berchin wrote:

Perhaps. But audiophiles are often willing to go to great lengths for the
ultimate in sound quality. Why compromise here?


I might argue with the last six letters after Audio - but that is neither
here nor there. What is relevant (in my opinion) is limiting technology vs.
open technology. If I manufacture a speaker that is open to many sorts of
driver (amplifiers), I am enabling my customers to make choices that
*include* my speaker without *excluding* the customer's existing equipment.
So, I am opening options to that customer.

In any case, when I heard my first pair of planar speakers (Accoustat), I
was impressed enough to consider them as compared to AR 11s. But, when I
heard my first pair of Maggies, that was that. My brother has those
Accoustats in a small room with good proportions, and they do exceedingly
well. That room is the size of my hobby room today. The Maggies FILL a room
that is 17 x 26 x 10. Yes, I have a brute-force amp driving them, but it
could be any-of-several.

Peter Wieck
Melrose Park, PA
_______________________________________

I apologize, but I've lost the earlier thread in which you identified which
Maggie you are using, and whether they are still made today. Have you heard
there most recent top-of-their line?

Ed Presson


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Peter Wieck Peter Wieck is offline
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Default Electrostatics, anyone?

I apologize, but I've lost the earlier thread in which you identified which
Maggie you are using, and whether they are still made today. Have you heard
there most recent top-of-their line?

Ed Presson


I have and they are stunning.

I have the MG-III with the external crossover and ribbon tweeter. It may be the 'a' version as it does not need the additional resistor on the tweeter. Their part numbers get somewhat muddled during transitions.

Peter Wieck
Melrose Park, PA

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