The Theremin , (also thereminvox or aetherphone) is one of the first fully electronic musical instruments. It was invented by Russian inventor Léon Theremin in October 1920 after the outbreak of the Russian civil war. Its invention grew out of a search for ways to detect movement. It was the first musical instrument to be played without being touched. The control section has two metal antennae to sense the positions of the player's hands. One hand controls the pitch. The other hand controls the volume. To play the theremin, the player moves his hands around the two metal antennas. The electric signals from the theremin are amplified and sent to a loudspeaker.