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In 1947, Arthur Janszen, a young Naval engineer, took part 
in a research project for the Navy. The Navy was interest-
ed 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 peri-
od were too nonlinear in phase and amplitude response to 
meet his criteria. Janszen believed that electrostats were inher-
ently 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 fre-
quency 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 electrostat-
ics permit the use of diaphragms that are low in mass, large 
in area and uniformly driven over their surfaces by electro-
static 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 played 
very loud, it had poor bass performance, it presented a dif-
ficult 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 
loudspeaker 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 presi-
dent of Sound Lab. When Janszen 
Corporation was sold, the RTR
l o u d s p e a k e r   c o m p a n y   b o u g h t
half of the production tooling. This 
tooling was used to make the elec-
trostatic 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 princi-
ple. Today’s electrostats use advanced insulation techniques 
or provide protection circuitry. The poor dispersion proper-
ties 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 sensitivity have also been increased.

These developments allow the consumer 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.

18     Electrostatic History