In article , Patrick Turner
wrote:


"Dave Plowman (News)" wrote:

In article , François Yves
Le Gal wrote:
How do you get 'resonances' in a speaker without, effectively, a
box?

Well, from the frame, the diaphragm, the stator, nearly everything.
You don't need a box in order to get resonances: how does a tuning
fork work?

A tuning fork is designed to resonate. Box speaker makers hopefully
try and get rid of the natural resonances that these have.

You'd have to try very hard to get resonances within the audio band
with the panels fitted to the Quad design.

Lynn Olson says Quad speakers, along with many others have considerable
resonances.

It would interesting to know what he means by 'considerable' in this
context. I would have expected that the level of resonances in an ESL tend
to be much smaller than in conventional cone-and-box speakers.

What is a tightly stretched diaghragm? Its a kind of drum without body
of air concealed nearby. It will have resonances.

Agreed. However the skin resonances are essentially transverse. They
can be easily excited by being hit at a single point by something like a
drumstick. However in the ESLs the forces tend to be applied in a way that
distributes them across the surface. Thus you should find that the 'skin'
resonances don't get exited to the same extent. Exception being the LF
resonance of the skin.

The mass of the diaphram is also quite small, so the amount of kinetic
energy stored in the movement in an ESL is, I suspect, much less than in a
conventional speaker. and I suspect the elastic energy stored in the
diaphragm restoring forces is also quite small. Don't know the thickness
or mass/area of drumskins, but I'd suspect they have much higher values
than the diaphragm in an ESL as people hit drumskins, but try to avoid
doing this with ESLs. :-)

So from an 'academic' POV you can say the resonances have a physical basis.
But in practice, they may be far smaller in an ESL than in typical
conventional speakers. I can't recall seeing any 'waterfall' decay
measurements of this offhand, but I'd suspect they show the difference OK.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

Stewart Pinkerton wrote:
On Mon, 21 Mar 2005 17:40:48 +1100, "Phil Allison"
wrote:


"Stewart Pinkerton"

Dave Plowman

You'd have to try very hard to get resonances within the audio band with
the panels fitted to the Quad design.

Not at all, in fact there are noticeable resonances in the bass region
from the diaphragms, plus mid-treble frame resonances.


** And this Vile Pommy Nazi claims he does NOT *posture* here as a Quad
ESL expert ???


And this ignorant dozy ocker doesn't agree with what I said?

He is not , just a misplaced pommie ******* .. would you like it back ?

Stewart Pinkerton wrote:
On Mon, 21 Mar 2005 17:43:17 +1100, "Phil Allison"
wrote:


"Stewart Pinkerton"

How do you get 'resonances' in a speaker without, effectively, a box?

The same way you get resonances in any drumskin, plus the frame isn't
too rigid.


** More utter bull**** from a know nothing ******.


You really are a dumb ****, aren't you Phil? Care to explain why an
ELS diaphragm is *not* like a drumskin? Or how the typically skinny
frame can be totally rigid? Too many tinnies again?
Careful now , he once bought some Quads . ( ask how long it took to get
the money back )and know everything about them
"rolls eyes"

In article ,
Stewart Pinkerton wrote:
How do you get 'resonances' in a speaker without, effectively, a box?

The same way you get resonances in any drumskin,

The resonance from a drum depends very much on the tension of the skin.

plus the frame isn't too rigid.

Doesn't need to be.

I'm not denying there could be *some* resonance - as with everything if
you have sensitive measuring equipment - just that they're insignificant.

--
*I didn't fight my way to the top of the food chain to be a vegetarian.

Dave Plowman London SW
To e-mail, change noise into sound.

"atec" = " a**** "

He is not , just a misplaced pommie ******* .. would you like it back ?


** My grandparents were originally from the UK.

But a ******* like "a****" has no idea who his father or mother were at
all.





.............. Phil

"atec" = "a****"

Careful now , he once bought some Quads .


** For 26 years I owned, constantly used, very occasionally repaired and
regularly demoed to friends a pair of ESL57s.

It brought about decisions by them to purchase a total of 6 more pairs of
ESL57s.

Bet "a****" has never even heard them.




.............. Phil

Phil Allison wrote:
"atec" = " a**** "


He is not , just a misplaced pommie ******* .. would you like it back ?



** My grandparents were originally from the UK.

But a ******* like "a****" has no idea who his father or mother were at
all.





............. Phil


you seem lost fill . cant find your penis ?
maybe you dole cheque hasn't been delivered so the supply of $4.99
cask wine has run out ?
either way the point in your post is lost...
perhaps you might try this time in your reply rant / threaten to make
a point ...
Oh and did I mention your an utter and total f&ckwit / pillock /****** ?

Phil Allison wrote:
"atec" = "a****"


Careful now , he once bought some Quads .



** For 26 years I owned, constantly used, very occasionally repaired and
regularly demoed to friends a pair of ESL57s.

It brought about decisions by them to purchase a total of 6 more pairs of
ESL57s.

Bet "a****" has never even heard them.




............. Phil



your point fill your point
keeps getting lost somewhere in the ether ...
perhaps if you "realy" could afford such speakers and other HiFi toys
we as a group might offer you more right of passage (that Tandy stuff
you got at the dump doesn't count), of course that would require some
effort on your part not to be an utter ****** / pillock /tosspot .

"atec" = "a****"

either way the point in your post is lost...


** **** off you drunken turd.





.............. Phil

"atec" = "a****"


your point fill your point
keeps getting lost somewhere in the ether ...



** **** off - you drunken turd.




............. Phil

Phil Allison wrote:

"Patrick Turner"


Lynn Olson says Quad speakers, along with many others have considerable
resonances.

** He is a liar - just like the ****ing, asinine Turneroid.

Because I summarize what another says, it does not make me a liar,
since my post which you snipped does not indicate that I quantified the
resonances,
or verified what Lynn Olson said.

But your post indicates to all you lack any comprehension abilities,
and you accuse others of what you are yourself.

There is nothing you have ever said that indicates Quad speakers can be
proven not to have resonant
behaviour, although most concede the resonances are in fact of small
significance when compared to other speakers such as dynamics in boxes.

Lynn Olson has a considerable amount to say about speakers,
and not all is balderdash.

Patrick Turner.



.............. Phil

"Patrick Turner" = RATs biggest public menace

Phil Allison wrote:


Lynn Olson says Quad speakers, along with many others have considerable
resonances.

** He is a liar - just like the ****ing, asinine Turneroid.

Because I summarize what another says, it does not make me a liar,


** Correct - you are king size one right off your own initiative.


since my post which you snipped does not indicate that I quantified the
resonances, or verified what Lynn Olson said.


** Add " insane liar " to my previous comments.


although most concede the resonances are in fact of small
significance when compared to other speakers such as dynamics in boxes.


** That flies right in the face of the original wild assertion I disputed:

" Lynn Olson says Quad speakers, along with many others have considerable
resonances. "

The Turneroid ****wit just completely contradicted himself - yet again !!
..


Lynn Olson has a considerable amount to say about speakers,
and not all is balderdash.


** Maybe, or maybe not.

But *every single thing* that criminal Turneroid ****wit says about Quads
is malicious bull****.




................ Phil

Delete a pile of insults and BS from PA,

Lynn Olson has a considerable amount to say about speakers,
and not all is balderdash.

** Maybe, or maybe not.

That is the point I made, simply to stir interest in
whatever Mr Olson may have said.
Many would think his concerns are insignificant.

Maybe if you read what Mr Olson said, you'd
be better equipped to discuss matters.


Patrick Turner

On Mon, 21 Mar 2005 18:27:08 +1100, "Phil Allison"
wrote:


"Stewart Pinkerton"


You'd have to try very hard to get resonances within the audio band with
the panels fitted to the Quad design.

Not at all, in fact there are noticeable resonances in the bass region
from the diaphragms, plus mid-treble frame resonances.


** And this Vile Pommy Nazi claims he does NOT *posture* here as a Quad
ESL expert ???

And this ignorant dozy ocker doesn't agree with what I said?


** The Vile Pommy Nazi did not say anything specific - he merely and
as usual regurgitated opinionated ****e from some audiophool's review,
website or usenet forum.

Nope, I applied my extensive engineering knowledge, plus you can
*hear* some of these resonances. The Quad's one of the better ones in
this regard, but a Martin-Logan CLS has a *very* nasty frome resoance
at about 10kHz.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Mon, 21 Mar 2005 10:10:34 +0000 (GMT), "Dave Plowman (News)"
wrote:

In article ,
Stewart Pinkerton wrote:
How do you get 'resonances' in a speaker without, effectively, a box?

The same way you get resonances in any drumskin,

The resonance from a drum depends very much on the tension of the skin.

Indeed, and without tension in the diaphtagm, the speaker wouldn't
work.

plus the frame isn't too rigid.

Doesn't need to be.

Sure it does - there is for instance a horrible and *very* audible
frame resonance in the Martin-Logan CLS. And why do you suppose that
one of the major differences between the '63 and 988/9 Quads is that
the new one has a *much* stiffer frame?

I'm not denying there could be *some* resonance - as with everything if
you have sensitive measuring equipment - just that they're insignificant.

See above - Quad wouldn't have made the frame (expensively) stiffer
unless they felt that this would improve the sound. Note that a
stiffer frame was alwats regarded as the reson for the US-spec '63
being preferred, and note also that this is the main modification in
the quad of Quads which are at the heart of Alastair
Robertson-Aitken's legendary SME listening room.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Mon, 21 Mar 2005 18:39:43 +1100, "Phil Allison"
wrote:


"Stewart Pinkerton" wrote in message
.. .
On Mon, 21 Mar 2005 17:43:17 +1100, "Phil Allison"
wrote:

"Stewart Pinkerton"

How do you get 'resonances' in a speaker without, effectively, a box?

The same way you get resonances in any drumskin, plus the frame isn't
too rigid.


** More utter bull**** from a know nothing ******.

You really are a dumb ****, aren't you Phil? Care to explain why an
ELS diaphragm is *not* like a drumskin?


** One does not hit it with a stick for a start.

Even the dumbest of Vile Pommy Cretins can figure that one out.

Apparently, this dumbest of ignorant ozzies can't figure out that the
input signal from the amp does the same thing if it's playing
percussion.

Or how the typically skinny
frame can be totally rigid


** No need to be.

Dumb as a box of rocks...................
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Mon, 21 Mar 2005 19:19:24 +1100, "Phil Allison"
wrote:

"Patrick Turner"

Cone speakers have notoriously bad resonances in their cones, and
ESL have resonances in their panel diaphragms.

** Massive lie.

Simple fact, that you're too dumb to understand.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Mon, 21 Mar 2005 12:59:54 +1100, "Phil Allison"
wrote:


"Dave Plowman (News)"

How do you get 'resonances' in a speaker without, effectively, a box?


** Boxes will have internal sound pressure reflections between the sides -
this is one source of resonances. The materials the box is made from
resonate as well - just tap one of the panels with your knuckle to hear
them. The materials the drivers cones and domes are made from ( paper,
plastic and metal) have audible resonances. All these resonances operate
simultaneously with a conventional box speaker system, they "colour" the
sound heard and are impossible to completely eliminate.

However, a sheet of plastic film with barely any mass ( so no ability to
store energy) which is driven by a coherent (electrostatic) force that is
spread evenly all over its surface is virtually resonance free.

Not exactly true. You just described a drum! The electrostatic force may dampen
the resonance, and of course a feedback amp in circuit would also do that, but
all physical objects have a natural resonance. In the case of an E-spk membrane,
the tightness would determine it's resonance, just like a drum. I would imagine
the membrane would be loose enough to put the resonance out of the audio band,
could even be less than 1hz.

A simple demo, used by Peter Walker, is to hold a frame with a sheet of such
plastic film in front of someone's face when they speak and note that the
sound is quite unaffected.

This would show that the membrane is thin enough to pass the sound, and probably
that it's resonance is so small in effect that it doesn't affect the sound
either. Of course, just the plastic itself is not proof of anything, you would
need the actual spk frame itself, and it's tension and other properties.

But I sure can't see anyone designing a drum into an E-spk!!

On Mon, 21 Mar 2005 17:11:00 +0000 (UTC), Stewart Pinkerton
wrote:

On Mon, 21 Mar 2005 18:39:43 +1100, "Phil Allison"
wrote:


"Stewart Pinkerton" wrote in message
. ..
On Mon, 21 Mar 2005 17:43:17 +1100, "Phil Allison"
wrote:

"Stewart Pinkerton"

How do you get 'resonances' in a speaker without, effectively, a box?

The same way you get resonances in any drumskin, plus the frame isn't
too rigid.


** More utter bull**** from a know nothing ******.

You really are a dumb ****, aren't you Phil? Care to explain why an
ELS diaphragm is *not* like a drumskin?


** One does not hit it with a stick for a start.

Even the dumbest of Vile Pommy Cretins can figure that one out.

Apparently, this dumbest of ignorant ozzies can't figure out that the
input signal from the amp does the same thing if it's playing
percussion.

Well, he's not a drummer! Or a musician of any kind, as a matter of fact. Quite
talentless I'm afraid.

Or how the typically skinny
frame can be totally rigid


** No need to be.

Dumb as a box of rocks...................

You got something against rocks?!?!? LOL!!!

"Stewart Pinkerton" .
"Phil Allison"


You'd have to try very hard to get resonances within the audio band
with
the panels fitted to the Quad design.

Not at all, in fact there are noticeable resonances in the bass region
from the diaphragms, plus mid-treble frame resonances.


** And this Vile Pommy Nazi claims he does NOT *posture* here as a
Quad
ESL expert ???

And this ignorant dozy ocker doesn't agree with what I said?


** The Vile Pommy Nazi did not say anything specific - he merely
and
as usual regurgitated opinionated ****e from some audiophool's review,
website or usenet forum.

Nope, I applied my extensive engineering knowledge,


** Pinko has no such thing.

The posturing Pommy Prick is nothing but a bloody charlatan and a
congenital LIAR !!!



" Stewart Pinkerton | Massive Fart - All else is Bull**** "



............. Phil

"Patrick Turner" = vile, congenital Liar

Lynn Olson has a considerable amount to say about speakers,
and not all is balderdash.

** Maybe, or maybe not.

That is the point I made,


** Not any sort of point at all.

simply to stir interest in
whatever Mr Olson may have said.


** How asinine - might as well debate what the ******'s cat said.


Many would think his concerns are insignificant.


** Facts matter - the opinions of ******s with vested interests do not.

The Turneroid is in the latter group.


Maybe if you read what Mr Olson said,


** Facts matter - the opinions of ******s with vested interests do not.


Alluding to the invisible words of some absent NON expert if a despicable
debating cheat.

But nothing is too low for that Turneroid Pile of **** to stoop to.





............... Phil

...
"Phil Allison"

** Boxes will have internal sound pressure reflections between the
ides -
this is one source of resonances. The materials the box is made from
resonate as well - just tap one of the panels with your knuckle to hear
them. The materials the drivers cones and domes are made from ( paper,
plastic and metal) have audible resonances. All these resonances operate
simultaneously with a conventional box speaker system, they "colour" the
sound heard and are impossible to completely eliminate.

However, a sheet of plastic film with barely any mass ( so no ability to
store energy) which is driven by a coherent (electrostatic) force that is
spread evenly all over its surface is virtually resonance free.

Not exactly true. You just described a drum!


** Bull**** - a drum skin has considerable mass, very little damping a
AND is struck at one point.


A simple demo, used by Peter Walker, is to hold a frame with a sheet of
such
plastic film in front of someone's face when they speak and note that the
sound is quite unaffected.

This would show that the membrane is thin enough to pass the sound, and
probably
that it's resonance is so small in effect that it doesn't affect the sound
either.


** QED.


Of course, just the plastic itself is not proof of anything,


** It proves the diaphragm is a near perfect sound reproducer.






............. Phil

On Mon, 21 Mar 2005 20:33:06 -0500, wrote:

In the case of an E-spk membrane,
the tightness would determine it's resonance, just like a drum. I would imagine
the membrane would be loose enough to put the resonance out of the audio band,
could even be less than 1hz.

Unfortunately that high of a compliance isn't possible given
the constraints of practical diaphragm-stator spacing. Practical
electrostatic speakers have fundamental resonances in the tens
of Hertz range. The QUAD Mark 1 from 1957 has a design center
F-sub-S of about 70 Hz, for example.

Choice of fundamental resonance frequency is actually one of the
toughest and most interesting parts of the design, because the
resonance is used to extend response lower than a free-air
diaphragm of those dimensions would achieve. Below the dimensional
limit all diaphragms' responses fall at 6 dB/octave. Choices
must be made.

Chris Hornbeck

"Stewart Pinkerton" = absolute, bloody ****WIT
"Phil Allison"


You really are a dumb ****, aren't you Phil? Care to explain why an
ELS diaphragm is *not* like a drumskin?


** One does not hit it with a stick for a start.

Even the dumbest of Vile Pommy Cretins can figure that one out.

Apparently, this dumbest of ignorant ozzies can't figure out that the
input signal from the amp does the same thing if it's playing
percussion.


** What - a little drum stick jumps out and whacks the diaphragm at one
spot ????

Pinko's crass Pommy stupidity is completely without bounds.

A champion arse among arseholes.



" Stewart Pinkerton | Massive Fart - All else is Bull**** "




............... Phil

"Stewart Pinkerton"... criminal LIAR
"Phil Allison"


Cone speakers have notoriously bad resonances in their cones, and
ESL have resonances in their panel diaphragms.

** Massive lie.

Simple fact,


** Since when has that congenital, lying POS Pinkerton had any idea what a
fact is ???





............ Phil

This thread can't be good for my blood pressure. I have never heard so
much total ignorance spouted on Quad ESL in my entire life as on two
audio conferences, and most of the crap being shovelled ia coming out
of the mouth of an "engineer" who poses as an expert.

Can somebody please take this total poseur Pinkerton aside and explain
to him how the signal is applied to the diaphragm.

At the same time, mention to him casually the actual mass of the
film... (Casually because if you correct his misconception he jerks
himself up and starts a flame war.)

Thanks a lot. You are a life-saver.

Andre Jute
Jesus. Talk about angels dancing on the head of pin.

Stewart Pinkerton wrote:
On Mon, 21 Mar 2005 18:39:43 +1100, "Phil Allison"
wrote:


"Stewart Pinkerton" wrote in message
.. .
On Mon, 21 Mar 2005 17:43:17 +1100, "Phil Allison"
wrote:

"Stewart Pinkerton"

How do you get 'resonances' in a speaker without, effectively, a
box?

The same way you get resonances in any drumskin, plus the frame
isn't
too rigid.


** More utter bull**** from a know nothing ******.

You really are a dumb ****, aren't you Phil? Care to explain why
an
ELS diaphragm is *not* like a drumskin?


** One does not hit it with a stick for a start.

Even the dumbest of Vile Pommy Cretins can figure that one out.

Apparently, this dumbest of ignorant ozzies can't figure out that the
input signal from the amp does the same thing if it's playing
percussion.

Or how the typically skinny
frame can be totally rigid


** No need to be.

Dumb as a box of rocks...................
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Phil Allison wrote:

charlatan and a
congenital LIAR !!!

That would be Fill ?

Always though you were a bit strange ,
in particular those cold dark night in the Brothers dorm
when you cuddled just a little to close .



Fill Aliceson Made of Bull**** "



............ Phil

On Tue, 22 Mar 2005 02:32:03 GMT, Chris Hornbeck
wrote:

On Mon, 21 Mar 2005 20:33:06 -0500, wrote:

In the case of an E-spk membrane,
the tightness would determine it's resonance, just like a drum. I would imagine
the membrane would be loose enough to put the resonance out of the audio band,
could even be less than 1hz.

Unfortunately that high of a compliance isn't possible given
the constraints of practical diaphragm-stator spacing. Practical
electrostatic speakers have fundamental resonances in the tens
of Hertz range. The QUAD Mark 1 from 1957 has a design center
F-sub-S of about 70 Hz, for example.

Choice of fundamental resonance frequency is actually one of the
toughest and most interesting parts of the design, because the
resonance is used to extend response lower than a free-air
diaphragm of those dimensions would achieve. Below the dimensional
limit all diaphragms' responses fall at 6 dB/octave. Choices
must be made.

Exactly correct - give that man a kewpie doll! My own Apogee Duetta
Sigs use the same technique to get very strong 30Hz response from a
dipole only two feet wide. Now, do you suppose that the potty-mouthed
Allison will ever understand this basic physics?
--

Stewart Pinkerton | Music is Art - Audio is Engineering

In article ,
Stewart Pinkerton wrote:
One does not hit it with a stick for a start.

snip

Apparently, this dumbest of ignorant ozzies can't figure out that the
input signal from the amp does the same thing if it's playing
percussion.

Only if you over drive it to the point where it arcs...;-)

--
*If tennis elbow is painful, imagine suffering with tennis balls *

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman
Stewart Pinkerton.

Apparently, this dumbest of ignorant ozzies can't figure out that the
input signal from the amp does the same thing if it's playing
percussion.

Only if you over drive it to the point where it arcs...;-)



** ROTFL

I have heard that happen too !!!!!



............... Phil

Stewart Pinkerton wrote:

On Mon, 21 Mar 2005 18:39:43 +1100, "Phil Allison"
wrote:


"Stewart Pinkerton" wrote in message
.. .
On Mon, 21 Mar 2005 17:43:17 +1100, "Phil Allison"
wrote:

"Stewart Pinkerton"

How do you get 'resonances' in a speaker without, effectively, a box?

The same way you get resonances in any drumskin, plus the frame isn't
too rigid.


** More utter bull**** from a know nothing ******.

You really are a dumb ****, aren't you Phil? Care to explain why an
ELS diaphragm is *not* like a drumskin?


** One does not hit it with a stick for a start.

Even the dumbest of Vile Pommy Cretins can figure that one out.

Apparently, this dumbest of ignorant ozzies can't figure out that the
input signal from the amp does the same thing if it's playing
percussion.

Wait a minute, you are wrong Pinky.
The percussion sound you hear from an ESL is produced by
signal applied to the whole surface of the diaphragm.

And although it is conceivable that such signals might excite some resonances,

its not in any way like when a dude hits a drumskin with a stick, temprarily
deforming the skin in a local area, and sending ripples out across the skin,
and exciting a mass of trapped air.



Or how the typically skinny
frame can be totally rigid


** No need to be.

Dumb as a box of rocks...................

I tend to agree with Phil on this.
You can talk to someone through a diaphragm
without any great deal of coloration. It indicates the very low mass
of the diaphragm can't resonate much at all, and beating it with a stick
won't make it behave like a drum to any great extent.
The not so rigid diaphram moves as a voltage controlled
bit of almost nothing.
The diaphragm is there to connect an electric charge variation to
air each side of it.
It just hangs a slightly movable charge in midair, and the thinner the
diaphragm the better.

Patrick Turner.




--

Stewart Pinkerton | Music is Art - Audio is Engineering

"Patrick Turner"

Wait a minute, you are wrong Pinky.
The percussion sound you hear from an ESL is produced by
signal applied to the whole surface of the diaphragm.

And although it is conceivable that such signals might excite some
resonances,
its not in any way like when a dude hits a drumskin with a stick,
temprarily
deforming the skin in a local area, and sending ripples out across the
skin,
and exciting a mass of trapped air.


I tend to agree with Phil on this.
You can talk to someone through a diaphragm
without any great deal of coloration. It indicates the very low mass
of the diaphragm can't resonate much at all, and beating it with a stick
won't make it behave like a drum to any great extent.


The not so rigid diaphram moves as a voltage controlled
bit of almost nothing.


** Exactly.


The diaphragm is there to connect an electric charge variation to
air each side of it.
It just hangs a slightly movable charge in midair, and the thinner the
diaphragm the better.



** My God - I think he is finally getting it !!!

The rain is Spain falls mainly on the ......




............. Phil

I used to repair 57's in the 70's.

The replacement diaphgragms came with the plastic covers loose; once the panel
was installed you had to use a heat gun to shrink the cover into place.
The problem with this procedure was that as done in the field (and I was
supervised by someone who was authorized by Quad for these repairs) there was
no way to get the shrinking to be even.

I don't know about the factory units, but any units we repaired would have
areas of the sheets under different tensions, and these probably had a
measurable impact. Compared to a Quad 57 ESL with dead panels the repaired
speaker sounded superb.

The worst case of this kind of effect I saw was in a Dayton-Wright XG8 III
which was tested using one of the devices that applies a tone burst with
a microphone whose output is gated to only accept direct sound from the
speaker. This particular unit sound OK, but a little weird; the frequency
response overall was quite flat but superimposed was a comb filter made up
of all the various resonances (probably in the gas bag that Dayton-Wright
used to contain the gas which allowed them to increase the voltage to the
panels). There were dozens of very narrow (high Q) resonances superimposed
on the output, some 20 to 40db deep.

I personally preferred the double KLH Nine setup to the single pari of 57's
in the 70's, although a double pair stacked vertically with a subwoofer was
a very popular system among the high end community at that time.

In my home setup right now I use a pair of old University 315-C's which play
nice and loud with a dB preamp and NAD 2140 power amp. I would like to find
out which driver the tweeter used, since one of my 3 has a marginal diaphragm
(I've been told it's a T50 or T60).

My weirdest tube project was a 150 wpc amp based on the Hafler "Sovereign
120" using the Paoli 60M driver design. The power supplies were a pair of
Kepco 500V 500ma regulated units with 8 6080's in each unit, plus 10,000
uf of filter caps in each channel. I got one channel running with 70V RMS
into 8 ohms, but then realized I'd just build a lethal accident waiting to
happen unless I dedicated a room to the Nines, the Hartley 24 subwoofer, and
the amplifiers. My rec room furniture, however, still has has large sections
which are rack mounts for the amps and power supplies.

Mike Squires
--

Mike Squires (mikes at cs.indiana.edu) 317 233 9456 (w) 812 333 6564 (h)
mikes at siralan.org 546 N Park Ridge Rd., Bloomington, IN 47408

On Tue, 22 Mar 2005 02:32:03 GMT, Chris Hornbeck
wrote:

On Mon, 21 Mar 2005 20:33:06 -0500, wrote:

In the case of an E-spk membrane,
the tightness would determine it's resonance, just like a drum. I would imagine
the membrane would be loose enough to put the resonance out of the audio band,
could even be less than 1hz.

Unfortunately that high of a compliance isn't possible given
the constraints of practical diaphragm-stator spacing. Practical
electrostatic speakers have fundamental resonances in the tens
of Hertz range. The QUAD Mark 1 from 1957 has a design center
F-sub-S of about 70 Hz, for example.

Choice of fundamental resonance frequency is actually one of the
toughest and most interesting parts of the design, because the
resonance is used to extend response lower than a free-air
diaphragm of those dimensions would achieve.

I don't know what you mean here, I've seen 12" cardboard speakers with a
resonance of 15hz... what does size have to do with it?

Wouldn't the resonance have to do with how tight the membrane is installed?

Below the dimensional
limit all diaphragms' responses fall at 6 dB/octave. Choices
must be made.

I thought system fall off was 12db?

I have to say I don't know much about E speakers... had some E headphones once,
had no bass...

On Tue, 22 Mar 2005 13:28:11 +1100, "Phil Allison"
wrote:


...
"Phil Allison"

** Boxes will have internal sound pressure reflections between the
ides -
this is one source of resonances. The materials the box is made from
resonate as well - just tap one of the panels with your knuckle to hear
them. The materials the drivers cones and domes are made from ( paper,
plastic and metal) have audible resonances. All these resonances operate
simultaneously with a conventional box speaker system, they "colour" the
sound heard and are impossible to completely eliminate.

However, a sheet of plastic film with barely any mass ( so no ability to
store energy) which is driven by a coherent (electrostatic) force that is
spread evenly all over its surface is virtually resonance free.

Not exactly true. You just described a drum!


** Bull**** - a drum skin has considerable mass, very little damping a

Still, even if it doesn't affect the sound, all things have a resonance.

AND is struck at one point.

Do you think it makes a difference if something is hit by a stick or a magnetic
shock wave? Normal speakers aren't hit by sticks at one point but they certainly
resonate when activated by the voice coil.

I'm not arguing with your assessment of lack of system resonance, just
mentioning that all things have resonance.

On Wed, 23 Mar 2005 00:10:30 +1100, Patrick Turner
wrote:



Wait a minute, you are wrong Pinky.
The percussion sound you hear from an ESL is produced by
signal applied to the whole surface of the diaphragm.

And although it is conceivable that such signals might excite some resonances,

its not in any way like when a dude hits a drumskin with a stick, temprarily
deforming the skin in a local area, and sending ripples out across the skin,
and exciting a mass of trapped air.

I think this 'hit with a stick' thing is a red herring... You are in effect
saying that one can't play a drum by hitting it with a book or something that
affects the whole head - you are wrong! (it will just sound different) Also,
there are pre-tuned drum heads, no drum shell required. And have you ever seen
roto-toms? No shell either, so no air-mass.

Also, putting a mass into resonant vibration can be done with anything,
including an electrostatic force, ANYTHING that excites it to move.

The fact the resonance of the diaphragm of an E speaker doesn't affect the sound
doesn't mean it has NO resonance, just that it is damped and very small, and is
well controlled by the amplifier's feedback.

Now I forget the original OP topic! BUT in practical terms, I'd agree that the
resonance in an E speakers diaphragm isn't a factor in it's sound, and the light
diaphragm with 'full wide drive' is what gives it the advantage over a
cardboard/magnetic motor spk.

All this talk about those speakers makes me want a pair now! Hey Phil, got a
set to sell?

I'm sorry I wasn't clearer here. It's difficult to judge
a stranger's interests from newsgroup postings.

On Tue, 22 Mar 2005 20:15:28 -0500, wrote:

I don't know what you mean here, I've seen 12" cardboard speakers with a
resonance of 15hz... what does size have to do with it?

It has, as you say, nothing to do with it. Fundamental resonance
is related to the product of moving mass and compliance, only.

If you're from an electronics background, it's *exactly*
analogous to inductance and capacitance. If you're looking
for a hands-on conceptual framework, think about a rock
on the end of a spring, in gravity. The rock is the mass;
the spring is the compliance. Tap the rock and it will oscillate
up and down at the system's fundamental resonant frequency.


Wouldn't the resonance have to do with how tight the membrane is installed?

Yes, indeed. This is the only thing you have to adjust with
during manufacturing, and tensioning is very important. After
all, the *very same* membrane must be both radiating diaphragm
*and* suspension. T'ain't easy.


Below the dimensional
limit all diaphragms' responses fall at 6 dB/octave. Choices
must be made.

I thought system fall off was 12db?

Resonant systems fall off at 12 dB per octave per resonance, both
above and below resonance (*). This of course also applies to
electrostatic speakers.

Open-baffle or "panel" speakers have an additional issue. They
radiate, as all vibrating diaphragms do, equal energy in both
directions, "fore and aft". Without a box, aft, to contain and
dissipate the aft energy, it "leaks" around to the fore, cancelling
each other out, like antimatter in the hands of Scottie. "I
canna hold 'er no more, Cap'ain."

At short wavelengths, the radiating diaphragm is large, and
cancellation is minimal, but at long wavelengths, the radiating
diaphragm is small, cancellation is great, and the diaphragm flaps
around, generating a lotta fury but signifying nothing.

For example, try moving your hand fast enough to generate an
audible sound. Now, if you were (you're not are you?) Superman,
and could move your hand forward and back at, say, 1000 times
a second, you could make dangerously loud sounds with the same
sized hand. Wavelength; it's *everything* in acoustics.

So (sorry for the bandwidth), there is a transitional frequency
region where the cancellation effects start to be significant, and
it depends on the relative size of the baffle and wavelength.
Smaller than a wavelength is starting to be small; no getting
around it. A two foot wavelength is what frequency, class?

Two otherwise-nonObtainium effects: cancellation rolloff is at
6 dB per octave, and there's a null in the plane of the diaphragm
(at all frequencies, incidenatally), so room modes are excited
less.

(*) Don't worry about this. But you may find it interesting later.

Good fortune,

Chris Hornbeck

On Tue, 22 Mar 2005 20:42:54 -0500, wrote:

The fact the resonance of the diaphragm of an E speaker doesn't affect the sound
doesn't mean it has NO resonance, just that it is damped and very small, and is
well controlled by the amplifier's feedback.

I'd just like to agree with all of your post, and to add a
piggyback comment. Electrostatic speakers are often considered
to be "inefficient", therefore poorly coupled to the driving
amplifier and therefore indifferent to amplifier source impedance.

But actually, the "motor" in electrostatic speakers is of very
high efficiency and coupling is therefore very high. The misconception
arises from the considerable parasitic capacitance present. (But
it's "outside" the motor).



Your English is better than mine, and that's all I really can use,
but your syntax is extremely provocative. I can't place your
childhood language, even to within a continent. Sometimes it seems
north European; sometimes southeast Asian; very intriging.
Care to share?

Thanks,

Chris Hornbeck

wrote:

On Wed, 23 Mar 2005 00:10:30 +1100, Patrick Turner
wrote:



Wait a minute, you are wrong Pinky.
The percussion sound you hear from an ESL is produced by
signal applied to the whole surface of the diaphragm.

And although it is conceivable that such signals might excite some resonances,

its not in any way like when a dude hits a drumskin with a stick, temprarily
deforming the skin in a local area, and sending ripples out across the skin,
and exciting a mass of trapped air.

I think this 'hit with a stick' thing is a red herring... You are in effect
saying that one can't play a drum by hitting it with a book or something that
affects the whole head - you are wrong! (it will just sound different) Also,
there are pre-tuned drum heads, no drum shell required. And have you ever seen
roto-toms? No shell either, so no air-mass.

The sound of a drum re-produced by an ESL is done in a very different way
to how the sound is genarated at the drum.
The drum sound is due to a very asymetrical distribution of waves waves
across the drum skin, which has considerable weight compared to an ESL membrane.
The ESL membrane is excited over its total area in an evenly spread fashion
by an amplified mircrophone signal. The ripples across the membrane don't occur,
The almost massless diaphragm does not like to ripple or swing back and forth in air

to any great extent like resonant things do, and the resonaces of ESL are renowned
for being less than
most other transducers.




Also, putting a mass into resonant vibration can be done with anything,
including an electrostatic force, ANYTHING that excites it to move.

Well show us all what terrible resonaces exist in ESL.

The fact the resonance of the diaphragm of an E speaker doesn't affect the sound
doesn't mean it has NO resonance, just that it is damped and very small, and is
well controlled by the amplifier's feedback.

We are saying ESL resonance is small. I have not done the math to support
any idea how effective NFB control of the diaphragm is.
But if you tap a diaphragm, or play music alongside an ESL connected to an amp
with no signal, you'd expect to see an error message in the amp as it tries to
resist
the motion caused by the external sound or excitation.

I have never done this test.



Now I forget the original OP topic! BUT in practical terms, I'd agree that the
resonance in an E speakers diaphragm isn't a factor in it's sound, and the light
diaphragm with 'full wide drive' is what gives it the advantage over a
cardboard/magnetic motor spk.

All this talk about those speakers makes me want a pair now! Hey Phil, got a
set to sell?

I doubt he has, but why not try brand new ones from
http://www.eraudio.com.au

Patrick Turner

= a complete ****wit
"Phil Allison"


** Bull**** - a drum skin has considerable mass, very little damping a

Still, even if it doesn't affect the sound, all things have a resonance.


** Pure ****wittery.


AND is struck at one point.

Do you think it makes a difference if something is hit by a stick or a
magnetic
shock wave?


** Massively irrelevant.


Normal speakers aren't hit by sticks at one point


** They are driven by the end of a cylinder - a tiny area compared to the
area of the cone or dome.

OTOH an ESL is driven evenly and linearly cross the entire surface area and
the mass of that surface is miniscule.


but they certainly
resonate when activated by the voice coil.


** See above.


I'm not arguing with your assessment of lack of system resonance, just
mentioning that all things have resonance.


** Pure ****wittery.




............. Phil