Robert Moog for the booklet of the compilation “Ohm, The Early Gurus Of Electronic Music, 1948-1980” (Ellipsis Arts… 2000):
The theremin was one of the first electronic musical instruments. It was invented around 1920 by the Russian musician-physicist Léon Theremin. It is a space-controlled instrument. That is, the player determines the pitch and loudness of the instrument’s tone by moving her or his hands in the space around the instrument, without ever touching it. The sound suggests a violinist or singer but is distinctly unlike that of any traditional acoustic musical instrument. Because its pitch and loudness respond to every motion of the performer’s body, the theremin is inherently expressive-and difficult to play.
Leon Theremin was one of the founding fathers of electronic music technology. He developed many different types of electronic musical instruments and inspired innovators around the world to do the same. There is a continuous thread connecting Theremin’s early work not only with modern-day theremins, but also with a wide range of electronic keyboard instruments that have been manufactured since the 1930s.
The use of tape recorders as music production devices (rather than passive reproducers of performances) is a different branch of the music technology family tree. This branch began with Edgard Varèse, who assembled sounds with multiple disc recorders, and it continued with the many experimental composers who worked with tape recorders after 1945. In a typical early tape music studio, sounds were first recorded on tape from acoustic or electronic sources, then processed by electronic means such as filtering, modulation, and synthetic reverberation, and then assembled by mixing, tape splicing, and rerecording.
The modular electronic music synthesizers of the 1960s made by companies such as Buchla, Moog, and others combined some of the tone production and control features of theremins and other early instruments with the sorts of sound generation and processing that were developed by the post—World War II tape composers. Using the technical principle of voltage control, these large, telephone-switchboard-like instruments enabled musicians to shape and sequence sounds automatically and by purely electronic means. The explosion of synthesizer records in the late 1960s, and of live performance on synthesizers and other electronic instruments in the 1970s, represented the growing together of the innovative work started by Léon Theremin and the techniques developed of the tape music community.