The solo instrument that produces the melody in the title music is a theremin. It was invented by Russian scientist
Leon Theremin, and was first demonstrated in 1920. It predates the modern synthesizer by about forty years, but its uniqueness stems from the fact that it is the only instrument that is played without actually being touched. Its electronic circuits are controlled by two antennas, left and right of the instrument, toward which the player moves his or her hands. The closer the right hand to one antenna, the higher the pitch. Similarly the proximity of the left hand to the other antenna controls the volume. The theremin has a range well in excess of eight octaves, and is capable of all kinds of strange effects. These sounds, perhaps most famously heard as the lead instrument of the long-running "Doctor Who" series, have also been put to use in other science fiction and movies, including Sir
Alfred Hitchcock's
Cuéntame tu vida (1945) and
Robert Wise's
El día que paralizaron la Tierra (1951). This unique instrument has also been used on
The Beach Boys' song "Good Vibrations". The late
Clara Rockmore was the theremin's greatest virtuoso, and the instrument and its inventor were profiled in the documentary
Theremin: An Electronic Odyssey (1993).
