THE THEREMIN WAS invented by Leon Theremin of Leningrad, Russia in 1924 and it represented a
revolutionary change in thinking about how music could be produced, challenging
traditional stringed, brass and percussion musical instruments.
Comprising electronic oscillators, it allowed control over both
pitch and amplitude by moving the hands over sensor plates. Its design
eventually led to the development of the Moog Synthesiser and electronically
synthesised music in general.
Fig.1: the Theremin circuit involves three virtually identical oscillators, two to generate the tone and one to control the volume.
But the invention was not only instrumental in the development
of electronic music, it also had an impact on a free-form style of playing
music. The free gesture hand control afforded by the Theremin pre-empted the
modern Sensor Chair synthesiser controller where the whole body is a part of the
musical generation process.
Before this, Jimi Hendrix was creating new sounds by generating
feedback between his guitar and the amplified sound and then moving his body to
modulate the amplitude. It freed him from the restriction of generating music
solely by plucking the guitar strings.
The Theremin was commercially manufactured by the Radio-victor
Corporation of America (RCA) around 1929. It comprised a large box to which were
attached an antenna and wire loop. The antenna provided the control for the
pitch while the loop enabled the volume to be adjusted. Moving the right hand
toward the antenna would reduce the pitch while moving the hand away from the
antenna would increase the pitch.