ESL Bibliography
1/15/96
Compiled by Mark Rehorst
US Patents
You can search these and other patents
at IBM's patent database- www.patents.ibm.com.
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