Martin Logan Stage X Manuel De L'utilisateur page 29

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 creat-
ed 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 nota-
bly, 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 electro-
static loudspeaker design in Wireless World, a British magazine.
In these articles, Walker demonstrated the benefits of the elec-
trostatic loudspeaker. He explained
that electrostatics permit the use of dia-
phragms 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 con-
sumer product, the now famous Quad ESL. This speaker
immediately set a standard of performance for the audio indus-
try due to its incredible accuracy. However, in actual use, the
Quad had a few problems. It could not be played very loud,
it had poor bass performance, it presented a difficult load that
some amplifiers did not like, its dispersion was very directional
and its power handling was limited to around 70 watts. As a
result, many people continued to use box speakers with cones.
In the early 1960's Arthur Janszen joined forces with the KLH loud-
speaker company, and together they introduced the KLH 9. Due to
the large size of the KLH 9, it did not have as many sonic limitations
as the Quad. The KLH 9 could play markedly louder and lower in
frequency than the Quad ESL. Thus a rivalry was born.
Janszen continued to develop electrostatic designs. He
was instrumental in the design of the Koss Model One, the
Acoustech and the Dennesen speakers. Roger West, the chief
designer of the Janszen Corporation, became the president of
Sound Lab. When Janszen Corporation was sold, the RTR
loudspeaker company bought half of the production tooling.
This tooling was used to make the electrostatic panels for the
Servostatic, a hybrid electrostatic system that was Infinity's first
speaker product. Other companies soon followed; each with
their own unique applications of the technology. These include
Acoustat, Audiostatic, Beverage, Dayton Wright, Sound Lab and
Stax, to name a few.
Electrostatic speakers have progressed and prospered because
they actually do what Peter Walker claimed they would. The
limitations and problems experienced in the past were not
inherent to the electrostatic concept. They were related to the
applications of these concepts.
Today, these limitations have been resolved. Advancements
in materials due to the U.S. space program give designers the
ability to harness the superiority of the electrostatic principle.
Today's electrostats use advanced insulation techniques or
These developments allow
the consumer to own the
highest performance loud-
speaker products ever built.
the opportunity to own the highest performance loudspeaker
products ever built. It's too bad Rice and Kellogg were never
able to see just how far the technology would be taken.
provide protection circuitry. The poor
dispersion properties of early models
have been addressed by using delay lines,
acoustical lenses, multiple panel arrays
or, as in our own products, by curving the
diaphragm. Power handling and sensitiv-
ity have also been increased.
These developments allow the consumer
Electrostatic History 29