What's a Theremin?

The theremin or thereminvox is one of the earliest fully electronic musical instruments. Invented in 1919 by Russian Léon Theremin, the theremin is unique in that it requires no physical contact in order to produce music and was, in fact, the first musical instrument designed to be played without being touched. The instrument consists of a box with two projecting antennas around which the user moves his or her hands to play. To control the theremin, the musician stands in front of the instrument and moves his or her hands in the proximity of two metal antennas, the distance from the antennas determining frequency (pitch) and amplitude (volume). Small movements of the hands can create a tremolo or vibrato effect. Typically the right hand controls the pitch and the left hand is used for the volume, although some play left-handed. Based on the principle of heterodyning oscillators, the theremin generates an audio signal by combining two different but very high frequency radio signals. The capacitance of the human body close to the antennas causes pitch changes in the audio signal, in much the same way that a person moving about a room can affect television or radio reception. By changing the position of the hands relative to the vertical antenna, a performer can control the frequency of the output signal. Similarly, the amplitude of the signal can be affected by altering the hand's proximity to the looped antenna. The information above is excerpted from “Wikipedia”, located at the following URL: http://www.wikipedia.org