Electrostatic Loudspeaker History - Martin Logan classic esl 9 Manuel De L'utilisateur

E L E C TR OS TA T I C LO U D SP E AK ER HISTO RY
In the late 1800's, any loudspeaker was considered exotic.
Today, we take the wonders of sound reproduction for granted.
It was 1880 before Thomas Edison had invented the
first phonograph. This was a horn-loaded diaphragm
that was excited by a playback stylus. In 1898, Sir Oliver
Lodge invented a cone loudspeaker, which he referred to
as a "bellowing telephone", that was very similar to the con-
ventional cone loudspeaker drivers that we know today.
However, Lodge had no intention
for his device to reproduce music
because in 1898 there was no way
to amplify an electrical signal! As
a result, his speaker had nothing
to offer over the acoustical gramo-
phones of the period. It was not
until 1906 that Dr. Lee DeForrest
invented the triode vacuum tube.
Before this, an electrical signal could not be amplified. The
loudspeaker, as we know it today, should have ensued then,
but it did not. Amazingly, it was almost twenty years before
this would occur.
In 1921, the electrically cut phonograph record became
a reality. This method of recording was far superior to the
mechanically cut record and possessed almost 30 dB of
dynamic range. The acoustical gramophone couldn't begin to
reproduce all of the information on this new disc. As a result,
further developments in loudspeakers were needed to cope
with this amazing new recording medium.
By 1923, the decision was made to develop a complete musi-
cal playback system consisting of an electronic phonograph
and a loudspeaker to take advantage of the new recording
medium. The project to two young engineers, C. W. Rice and
E. W. Kellogg.
Rice and Kellogg had a well equipped laboratory at their dispos-
al. This lab possessed a vacuum tube amplifier with an unheard
of 200 watts, a large selection of the new electrically cut pho-
nograph records and a variety of loudspeaker prototypes that
had been collecting over the past decade. Among these were
Lodge's cone, a speaker that used compressed air, a corona dis-
charge (plasma) speaker, and an electrostatic speaker.
After a short time, Rice and Kellogg had narrowed the field of
"contestants" down to the cone and the electrostat. The out-
come would dictate the way that future generations would
refer to loudspeakers as being either "conventional" or "exotic".
Their electrostat was something to behold. This enormous
bipolar speaker was as big as a door. The diaphragm, which
was beginning to rot, was made of a pig intestine that was cov-
ered with fine gold leaf to conduct the audio signal.
Rice and Kellogg had
narrowed the field of
"contestants down" to the
cone and the electrostat.
ing rendition of the acoustic gramophone. Immediately, they
knew they were on to something big. The acoustic gramo-
phone was destined to become obsolete.
Due to Rice and Kellogg's enthusiasm, they devoted a con-
siderable amount of time researching the electrostatic design.
However, they soon encountered the same difficulties that
even present designers face; planar speakers require a very
large surface area to reproduce the lower frequencies of the
audio spectrum. Because the management considered large
speakers unacceptable, Rice and Kellogg's work on electro-
statics would never be put to use for a commercial product.
Reluctantly, they advised management to go with the cone.
For the next 30 years, the electrostatic design lay dormant.
During the Great Depression of the 1930's, consumer audio
almost died. The new electrically amplified loudspeaker
never gained acceptance, as most people continued to use
their old Victrola-style acoustic gramophones. Prior to the
end of World War II, consumer audio saw little, if any, prog-
ress. However, during the late 1940's, audio experienced
a great rebirth. Suddenly there was tremendous interest in
audio products, and with that, a great demand for improved
audio components. No sooner had the cone become estab-
lished than it was challenged by products developed during
this new rebirth.
When Rice and Kellogg began playing
the new electrically cut records through
the electrostat, they were stunned and
impressed. The electrostat performed
splendidly. They had never heard instru-
mental timbres reproduced with such
realism. This system sounded like real
music rather than the honking, squawk-
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