Martin Logan ElectroMotion ESL C Mode D'emploi page 12

performed splendidly. They had never heard
instrumental timbres reproduced with such realism.
This system sounded like real music rather than
the honking, squawking rendition of the acoustic
gramophone. Immediately, they knew they were
on to something big. The acoustic gramophone
was destined to become obsolete.
Due to Rice and Kellogg's enthusiasm, they
d e v o t e d a c o n s i d e r a b l e a m o u n t o f t i m e
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 electrostatics would never be put to use for a
commercial product. Reluctantly, they advised the
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,
progress. 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
established than it was challenged by products
developed during this new rebirth.
In 1947, Arthur Janszen, a young Naval engineer,
took part in a research project for the Navy.
The Navy was interested in developing a better
instrument for testing microphone arrays. The test
instrument needed an extremely accurate speaker,
but Janszen found that the cone speakers of the
period were too nonlinear in phase and amplitude
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response to meet his criteria. Janszen believed
that electrostats were inherently more linear than
cones, so he built a model using a thin plastic
diaphragm treated with a conductive coating. This
model confirmed Janszen's beliefs, for it exhibited
remarkable phase and amplitude linearity.
Janszen was so excited with the results that he
continued research on the electrostatic speaker
on his own time. He soon thought of insulating the
stators to prevent the destructive effects of arcing.
By 1952, he had an electrostatic tweeter element
ready for commercial production. This new tweeter
soon created a sensation among American audio
hobbyists. Since Janszen's tweeter element was
limited to high frequency reproduction, it often
found itself used in conjunction with woofers—
most notably, those from Acoustic Research.
These systems were highly regarded by all audio
enthusiasts.
As good as these systems were, they would soon
be surpassed by another electrostatic speaker.
In 1955, Peter Walker published three articles
regarding electrostatic loudspeaker design in
Wireless World, a British magazine. In these
articles, Walker demonstrated the benefits of
the electrostatic loudspeaker. He explained that
electrostatics permit the use of diaphragms that
are low in mass, large in area and uniformly
driven over their surfaces by electrostatic forces.
Due to these characteristics, electrostats have the
inherent ability to produce a wide bandwidth, flat
frequency response with distortion products being
no greater than the electronics driving them.
By 1956, Walker backed up his articles by
introducing a consumer product, the now famous
Quad ESL. This speaker immediately set a
standard of performance for the audio industry
due to its incredible accuracy. However, in actual
use, the Quad had a few problems. It could not be