Curious to know how other contributors of this thread are positioned while listening.
Both me and my speakers are well out into the room, the speakers are 6 feet apart and I find I get a more focused image with better depth if I'm a little closer to them than that, around about 5 ft or slightly less.
Peter Walker wrote an article in three parts about the electrostatic transducer in the Wireless World 1955.
Thanks.
Part 1 page 208 https://www.americanradiohistory.com/UK/Wireless-World/50s/Wireless-World-1955-05.pdf
Part 2 Page 265 https://www.americanradiohistory.com/UK/Wireless-World/50s/Wireless-World-1955-06.pdf
Part 3 page 381 https://www.americanradiohistory.com/UK/Wireless-World/50s/Wireless-World-1955-08.pdf
https://home.kpn.nl/verwa255/esl/ESL_English_2011.pdf
https://pdfs.semanticscholar.org/b286/d534ea293044ea304312b2afa86018913edc.pdf
George
Isn't stating opinion as fact in the "sloppy" category? 😉
It is an opinion well founded on facts.
Electrostatic voltmeter. Usually look like the pictures below. They draw zero current at DC and very little at AC. Sensitive instrument (or whats left of it) may still make them but they are all quite vintage.
I have two absolutely mint ones, I used to touch the input one in the morning in winter and watch all day as it slowly discharged a few electrons at a time.
Thank you George.Part 1 page 208 https://www.americanradiohistory.com/UK/Wireless-World/50s/Wireless-World-1955-05.pdf
Part 2 Page 265 https://www.americanradiohistory.com/UK/Wireless-World/50s/Wireless-World-1955-06.pdf
Part 3 page 381 https://www.americanradiohistory.com/UK/Wireless-World/50s/Wireless-World-1955-08.pdf
https://home.kpn.nl/verwa255/esl/ESL_English_2011.pdf
https://pdfs.semanticscholar.org/b286/d534ea293044ea304312b2afa86018913edc.pdf
George
Note in the first article he provides analysis on dispacement related distortion, up to 25% capacitance imbalance, distortion is still low.
We seem to have a wealth of listening experts here but a dearth of hearing experts.
One thing I didn’t see in that article you referenced but have read in other research, is that the ossicles seperate when exposed to loud noise for long periods. This is to protect the inner ear, maybe some do that better than others?
And if the hair growing out of my ears are any indication of cochlear hair re-growth I’m all good! 😛
Baxandell covered a lot in his chapter of Borwick's Loudspeaker & Headphone Handbook
Third edition, Section 3 (85 pages from Peter Baxandall)

George
Thank you George.
Note in the first article he provides analysis on dispacement related distortion, up to 25% capacitance imbalance, distortion is still low.
Sorry, IPad battery died..
The distortion analysis is good, but does not address the issue of current difference in the stator loops. As I pointed out, even a direct short to the stator will result in currents in the low nano amp range. The part per billion aspect of a two layer coat still holds no matter where the diaphragm is.
Earlier I stated "3D problem viewed as 1D". That was not a slight, it was a statement of the type of analysis being done. Simply viewing an estat as a position and time varying capacitor is one dimensional. Segmentation of the stator and driving it like a phased array turns it into a 3D problem.
1: the delay from ring to ring is electrically derived. Was it derived based only on speed of sound principles, or was the shear wave velocity of the stretched membrane considered?(ohm Walsh).
2: is membrane tension optimized for shear wave velocity, and are the edges supported by a feature which reflects the wave or absorbs it?
3: given the phased array drive, the e field the diaphram sees is no longer normal to the surface. Given that, now the charge transport velocity across the film comes into play. I've seen no discussion of that.
4: now that the e field is no longer normal to the surface, the relationship between the bias voltage and the stator voltage will have an impact on the lateral forces the charge on the film will see. A simple 1D analysis does not consider that.
It is that reason I asked previously if anybody has done polar plots vs bias voltage.
Oh, and the attempted slight against me, to stop trying to play Einstein? Nothing can be further from the truth. All I have done is provide a bog simple engineering analysis. So simple, that I didn't even have to take my shoes off to count past ten.
Jn
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Streng published results wrt charge movement on the membrane:
J.H. Streng; Charge Movement on the Stretched Membrane in a Circular Electrostatic Push-Pull Loudspeaker; JAES, Vol.38, No.5, 1990 May, 331
Harmonic distortion (at steady state excitation 😉 ) contribution negligible in a propperly designed speaker, linear distortion in the low frequency band is more severe.
It's available:
(PDF) Charge movements on the stretched membrane in a circular electrostatic push-pull loudspeaker
J.H. Streng; Charge Movement on the Stretched Membrane in a Circular Electrostatic Push-Pull Loudspeaker; JAES, Vol.38, No.5, 1990 May, 331
Harmonic distortion (at steady state excitation 😉 ) contribution negligible in a propperly designed speaker, linear distortion in the low frequency band is more severe.
It's available:
(PDF) Charge movements on the stretched membrane in a circular electrostatic push-pull loudspeaker
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And if the hair growing out of my ears are any indication of cochlear hair re-growth I’m all good! 😛
😀
maybe even buy some of whatever it is mark and Jakob is selling.....what exactly is that anyways?
I don't know, why don't you ask the "audio developer"?
I really have no idea who did this.@Hans Polak,
the steel frame (wasn't it by ?Arcisi?) was IMO an impressive progress and the newer chinese models tried to do something similar (therefore the additional strut on the backside for further stabilization.
But there are side handles for easy tranport, and an aluminium frame would not allow that force.
Hans
The arcici stands were the first I've seen, might be not the same but inspired by the same idea, lifting the Quads, stabilizing the frame structure and getting rid of the cloth:
Quad ESL 63 Speakers with Original Boxes Packing Manual + Optional Arcici Stands Photo #1402209 - US Audio Mart
Quad ESL 63 Speakers with Original Boxes Packing Manual + Optional Arcici Stands Photo #1402209 - US Audio Mart
Excellent, excellent...thank you..that is a great paper.Streng published results wrt charge movement on the membrane:
J.H. Streng; Charge Movement on the Stretched Membrane in a Circular Electrostatic Push-Pull Loudspeaker; JAES, Vol.38, No.5, 1990 May, 331
Harmonic distortion (at steady state excitation 😉 ) contribution negligible in a propperly designed speaker, linear distortion in the low frequency band is more severe.
It's available:
(PDF) Charge movements on the stretched membrane in a circular electrostatic push-pull loudspeaker
While he did not pursue the analysis of bias voltage sensitivity directly, his very last sentence pretty much says it all..
If linear operation of the speaker is desired, then additional measures will have to be taken to insure that the amount of charge on the membrane remains constant, especially in the case of large membrane deflections.
Nice, very nice..again, thank you.
john
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yep and still working from 1990 !I really liked AKG K1000 when I listened to them. Would probably never use them for various reasons, but they sounded great.
While he did not pursue the analysis of bias voltage sensitivity directly, his very last sentence pretty much says it all..
Same conclusion as the B&K analysis, for the microphone the negative capacitance IIRC compensates for the small geometric distortions.
I don't know, why don't you ask the "audio developer"?
Maybe I could pimp myself out as a audio gear reviewer.....that way I’d have a never ending river of new stuff to play around with.
All interested developers/manufacturers please send a pm for my shipping address. 🙂
No sense in keeping all of that golden ear goodness to myself! 😀
You may want to do something about the fur first, there are specialist tools for the jobNo sense in keeping all of that golden ear goodness to myself! 😀
Attachments
No, that's not what I have.The arcici stands were the first I've seen, might be not the same but inspired by the same idea, lifting the Quads, stabilizing the frame structure and getting rid of the cloth:
Quad ESL 63 Speakers with Original Boxes Packing Manual + Optional Arcici Stands Photo #1402209 - US Audio Mart
Apart from the side handles, there's optically very little difference with the originals.
Hans
Sorry, IPad battery died..
2: is membrane tension optimized for shear wave velocity, and are the edges supported by a feature which reflects the wave or absorbs it?
Jn
The tension is, with a safety margin, enough to counteract the electrical negative compliance. In esl57 and 63 at least no special feature for absobsion of reflections. The membrane is light enough for air load to dominate might mitigate reflexions a bit perhaps.
/örjan
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