120 Years of Electronic Music
The Audion Piano (1915)
De Forest playing the Audion Piano
Lee De Forest (Born: August 26, 1873, Council Bluffs, Iowa. Died June 30, 1961
) , The self styled "Father Of Radio" ( the title of his 1950
autobiography) inventor and holder of over 300 patents, invented
the triode electronic valve or 'Audion valve' in 1906- a much
more sensitive development of John A. Fleming's diode valve. The
immediate application of De Forest's triode valve was in the emerging
radio technology of which De Forest was a tenacious promoter.
De Forest also discovered that the valve was capable of creating
audible sounds using the "heterodyning"/beat frequency technique: a way of creating sounds by combining two high frequency signals to create a composite lower
frequency within audible range.
Lee De Forest's Triode Valve of 1906
De Forest Created the 'Audion Piano', the first vacuum tube instrument
in 1915. By creating The Audion Piano, De Forest had laid the blueprint for electronic instruments for the next fifty years until the emergence of transistor technology. The Audion Piano was a simple keyboard instrument. It
was the first instrument to use a beat-frequency or "heterodyning" oscillator
system and also the first to use body capacitance to control pitch and timbre ( The
heterodyning effect was later much exploited by the Leon Termen with
his
Theremin series of instruments and Maurice Martenot's
Ondes-Martenot amongst others. ).
The Audion Piano used a single triode valve per octave controlled by a set of keys allowing one monophonic
note to be played per octave. The output of the instrument was sent to a set of speakers that could be placed around a room giving
the sound a nvoel dimensional effect.
De Forest planned a later version
of the instrument that would have separate valves per key allowing
full polyphony- it is not known if this instrument was ever constructed.
Lee De Forest and radio broadcasting equipment
De Forest described the Audio Piano as capable of producing:
"Sounds resembling a violin, Cello, Woodwind, muted brass and
other sounds resembling nothing ever heard from an orchestra or
by the human ear up to that time - of the sort now often heard
in nerve racking maniacal cacophonies of a lunatic swing band.
Such tones led me to dub my new instrument the 'Squawk-a-phone'."
(Lee De Forest Autobiography "The Father Of Radio" 1915. P331-332)
"The Pitch of the notes is very easily regulated by changing the
capacity or the inductance in the circuits, which can be easily
effected by a sliding contact or simply by turning the knob of
a condenser. In fact, the pitch of the notes can be changed by
merely putting the finger on certain parts of the circuit. In
this way very weird and beautiful effects can easily be obtained."
De Forest, the tireless promoter, demonstrated his electronic
instrument around the New York area at public events alongside
fund raising spectacles of his radio technology. These events
were often criticised and ridiculed by his peers and led to a
famous trial where De Forest was accused of misleading the public
for his own ends:
"De Forest has said in many newspapers and over his signature
that it would be possible to transmit human voice across the Atlantic
before many years. Based on these absurd and deliberately misleading
statements, the misguided public ... has been persuaded to purchase
stock in his company. "
Advert for ealry Radio broadcasts
De Forest also collaborated with a skeptical Thadeus Cahill in
broadcasting early concerts of the
Telharmonium using his radio transmitters (1907). Cahill's insistence on using
the telephone wire network to broadcast his electronic music was
a major factor in the demise of the Telharmonium.
Vacuum tube technology was to dominate electronic instrument design
until the invention of transistors in the 1960's. The Triode amplifier
also freed electronic instruments from having to use the telephone
system as a means of amplifying the signal.
Lee De Forest in 1948
Sources:
Lee De Forest "Father Of Radio" (Autobiography).
© 120 Years Of Electronic Music 2005
