7) ESL Bibliography

by Mark Rehorst

updated November 2006

This page lists information resources for ESL builders.

Links:

I was going to put a lot of links in here, but they tend to rot and I don't have time to keep up with all of them, so I'm going to suggest that you do a web search on your favorite search engine.  Look for terms like "DIY Electrostatic Speakers" and you'll get hundreds of hits.  Be sure to check out The Audio Circuit.  There's a lot of good information there.

One warning about audio web sites in general:  there's a lot of nonsense out there about audio and you're bound to run into some of it.  If you are new to electronics and/or audio, be skeptical about claims that just don't seem to make sense.  Most of the nonsense is promulgated by people who have a financial interest in convincing you that it is true.  It is safest to consider ALL information from such sites as suspect.  There are plenty of other, good sites, so don't waste your time on the nonsense unless you just want to have a good laugh.

The patent list below will be updated soon- check back again...


US Patents
You can search these and other patents at the US Patent Office

2,631,196 Janszen, March 1953
Description of an ESL that has on fixed electrode, and electrically divided diaphragm to control directivity, frequency response, and impedance of the speaker.

2,896,025 Janszen, July 1959
Describes and ESL manufacturing process using wire grid fixed electrodes, one on either side of the diaphragm.

3,008,014 Williamson and Walker, Nov. 1961
Describes a method of makig ESLs with low distortion and a method of separatng them into different sections to reproduce different frequency ranges.

3,014,098 Malme, Dec. 1961
Provides a good, detailed description of ESL operation, and a design that incorporates segmented stators to control directionality at high frequencies.

3,668,335 Beveridge, June 1972
Describes a servo controlled ESL mounted in an enclosure, to allow low frequency reproduction, and with an acoustic lens to control high frequency dispersion. Patent includes schematics of vacuum tube servo control amplifier.

3,668,336 Wright, June 1972
Describes an ESL with electrical connections on one side of the speaker only,

3,778,562 Wright, Dec. 1973
Describes an ESL mounted in a sealed enclosure filled with a gas that acts as an acoustic lens to control the directionality of the driver and allows higher
operating voltages than would be possible in air, thus increasing the sensitivity of the driver..

4,289,936 Civitello, Sept. 1981
Describes an interesting inverse ESL with one perforated stator plate and two diaphragms on either side of it. The drivers are triangular, with multiple units
assembled into a kind of geodesic dome structure for control of directivity of the speaker.

4,703,509 Kanchev, Oct. 1987
Describes an ESL that uses stators with resistive properties to control frequency response and directivity.

British Patents

1,234,767 Enock, June 1971
Describes electrostatic transducers in which the stators are insulated to allow the use of high operating voltages, thereby increasing the sensitivity of the transducers.

1,239,658 Bowers and Greenwood, July 1971
Describes an electrostatic speaker that is built used printed circuit techniques, in which the stators are insulated to allow the use of high operating voltages,
thereby increasing the sensitivity of the drivers.


Articles:

An Electrostatic Speaker System, Roger Sanders, Speaker Builder magazine, 2/80-4/80. A very good series of articles on DIY ESL construction.

Sound Radiation From Circular Stretched Membranes in Free Space, J. H. Streng, published in the Journal of the Audio Engineering Society, Vol 37 No.
3, March 1989. A detailed mathematical analysis of circular ESL driver resonances and frequency response.

Books:
(Click on the title to order from Amazon)

Audio Amateur Loudspeaker Projects, contains a good DIY ESL article that originally appeared in Audio Amateur magazine. Available from Old Colony
Sound Lab, PO Box 243, Peterborough, N.H. 03458. Phone: 603-924-6526, fax: 603-924-9467.

Electrostatic Loudspeaker Design and Construction, by Ronald Wagner, published by Tab Books. Describes operating theory and construction of ESLs.
Available from Old Colony Sound Lab, PO Box 243, Peterborough, N.H. 03458. Phone: 603-924-6526, fax: 603-924-9467.

The Electrostatic Loudspeaker Design Cookbook, by Roger Sanders, 1995. Available from Old Colony Sound Lab, PO Box 243, Peterborough, N.H.
03458. Phone: 603-924-6526, fax: 603-924-9467.

Loudspeaker and Headphone Handbook, edited by John Borwick. ISBN no. 0-240-51371-1. Contains a mathematically detailed description of ESL operation written by Peter Baxandall, including enough detail about the venerable Quad ESL63 to allow close duplication of the design (if you're so inclined).

End

You may contact me at this address:

1) Principles of ESL operation

2) Materials Required

3) Diaphragm Stretcher

4) ESL Driver Construction

5) Support Frame Construction

6) Bias Power Supply Construction

7) ESL Bibliography and Links

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