Aphex 320D Compellor - Manual (Page 8)

320D
Compellor
Page 8 Page 9
circuit. They thought that all audio processors should be noticeable. We had to explain that
the unit was in fact working, and we asked them to listen to their mixes with and without
the Compellor. After they did that, they were amazed at the results. Meanwhile, broadcast-
ers were discovering the Compellor. They found it greatly enhanced their air chains. The
Compellor soon won the favor of broadcasters internationally.
Some owners may be interested in how the Compellor was first developed. The story begins
in Hawaii in 1982 when Donn Werrbach, a consulting broadcast engineer, undertook to design
an advanced AGC unit for on-air processing to improve the sound of radio stations. Werrbach
had been experimenting with broadcast audio processing for many years but needed to find a
good enough VCA (voltage controlled amplifier chip) to fully implement all the new processing
techniques he had discovered. A chance contact with Boyd Collings, who was then the Aphex
agent in Honolulu, introduced Werrbach to the type 1537A VCA chip which was produced and
sold by Aphex. Given a free sample, a couple of weeks time, and the inspiration brought by
the VCA’s fabulous performance, Werrbach produced the first Compellor prototype.
Werrbach’s prototype found its way not only into on-air trials but into a tape duplicating lab,
an album recording studio, and several live showrooms where it quickly proved its usefulness
as a gain controller without processing artifacts. At Boyd’s urging, Aphex’s product manager
Jon Sanserino visited Honolulu and auditioned Werrbach’s prototype at the Audissey record-
ing studio where he was intrigued by its possibilities. Finally, in 1983, an agreement was
reached between Werrbach and Marvin Caesar, the president of Aphex Systems, to produce
the Compellor as a product line.
The first unit rolled off the line in 1984 as the Aphex Model 300 Stereo Compellor. Patents
were secured for key inventions of the Compellor circuitry and are assigned exclusively to
Aphex Systems.
As a premier product line, Aphex decided to build the Model 300 to the highest commercial
standards including only the best available parts and construction techniques. As a result,
not only is the audio processing performance outstanding, but the reliability and long lifetime
of the product was assured. Thousands of Model 300’s are still in constant use today, some
with as much as 19 years of duty under 24-hour service!
The next models introduced were the Models 301 and 303 based on the Model 300 design.
The Model 301 was a single channel version, while the Model 303 was a Model 301 with an
Aural Exciter (tm) added. These models are also still in widespread use.
In 1991, Aphex released the Model 320 Dual/Stereo Compellor as an updated replacement
for the Model 300 Stereo Compellor. The principle functions were retained but many improve-
ments were implemented as well as new convenience features to make the Compellor even
easier to install and use. One such improvement was the conversion to a new and improved
proprietary VCA chip, the Aphex VCA1001, to replace the now obsolete 1537A. The great
success of the model 320 soon led to the Model 323 single channel Compellor with Aural
Exciter to replace the older Models 301 and 303.
3. Introduction
The Compellor has become the world standard audio level controller.
Understandably, we are very proud of that fact!