Filter
Top Products
Page6
Monolith III User's Manual
In the late 1800’s, any loudspeaker was
considered exotic. Today, most of us
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 loud-
speaker, which he referred to as a
“bellowing telephone”, that was very
similar to the conventional 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 gramophones 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 loud-
speaker, 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 pos-
sessed 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 loud-
speakers were needed to cope with
this amazing new recording medium.
By 1923, Bell Telephone Laboratories
made the decision to develop a
complete musical playback system
consisting of an electronic phonograph
and loudspeaker to take advantage of
the new recording medium. Bell Labs
assigned the project to two young
engineers, C.W. Rice and E.W. Kellogg.
Rice and Kellogg had a well equipped
laboratory at their disposal. This lab
possessed a vacuum tube amplifier
with an unheard of 200 watts, a large
selection of the new electrically cut
phonograph records and a variety of
loudspeaker prototypes that Bell Labs
had been collecting over the past
decade. Among these were Lodge’s
cone, a speaker that used compressed
air, a corona discharge (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 outcome would dictate the way that
future generations would refer to
loudspeakers as being either “conven-
tional”, or “exotic”.
Bell Laboratory’s 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 the membrane of a
pigs intestine that was covered with fine
gold leaf to conduct the audio signal.
When Rice and Kellogg began playing
the new electrically cut records through
the electrostat, they were shocked and
impressed. The electrostat 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 Kelloggs enthusiasm,
they devoted a considerable amount of
time researching the electrostatic
design. However, they soon encoun-
tered the same difficulties that even
present designers face; planar speak-
ers require a very large surface area to
reproduce the lower frequencies of the
audio spectrum. Because the manage-
ment at Bell Labs considered large
speakers unacceptable, Rice and
Kelloggs work on electrostatics would
never be put to use for a commercial
product. Reluctantly, they advised the
Bell management to go with the cone.
For the next thirty years the electrostatic
design lay dormant.
During the Great Depression of the
1930's, consumer audio almost died.
The new electrically amplified loud-
speaker never gained acceptance, as
most people continued to use their old
Victrola-style acoustic gramophones.
Prior to the end of World War II, con-
sumer 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 estab-
lished 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
History