The RCA Theremin holds a place in history as the first manufactured electronic musical instrument, and is credited with laying the foundation for all electronic music to come.
Further distinguishing the theremin from the traditional world of mechanical musical instruments (reeds, woodwinds, horns, strings, percussion, etc.), the theremin is the only instrument that is played without the performer ever touching it. To quote period advertising literature from RCA:
Simple and graceful movements of the hands produce and control the tone.
The theremin is named for its inventor, Lev Sergeyevich Termen, anglicized as Leon Theremin (born St. Petersburg, Russia, August 1896, died Moscow, November 1993). Theremin demonstrated his first working model of the instrument that bears his name in 1920 as the Etherphone, soon to be known as the Termenvox, or literally, Voice of Termen.
When properly adjusted and voiced, the RCA Theremin has a pitch range of 3.5 to 4 octaves, and a timbre that is somewhat like a cello at the low end and somewhere between violin and voice at the high end.
Quoting Dr. Robert Moog, the creator of the Moog synthesizer,
The theremin specifically, and Leon Theremin's work in general is the biggest, fattest, most important cornerstone of the whole electronic music medium. That's where it all began.
The theremin remained a laboratory curiosity from its inception until March 1922 when Theremin performed on the instrument for Lenin. The following December saw the beginning of several years of touring with the instrument in increasingly wider circles throughout Europe.
These tours culminated with Theremin's arrival in the U.S. for a prolonged stay, where he performed publicly for the first time at the Metropolitan Opera House in January 1928. At first, theremin instruments remained limited to just a few that Leon Theremin personally made, and Theremin himself trained a small group of musicians in the art of playing them.
Factory-made RCA Theremins were first demonstrated in music stores in several major U.S. cities on October 14, 1929 and were marketed primarily in 1929 and 1930. Theremins were luxury items, priced at $175.00, not including vacuum tubes and RCA's recommended Model 106 Electrodynamic Loudspeaker, which brought the total cost of buying a complete theremin outfit up to about $232.00. This translates to about $3,123 in today's currency.
Although various factors contributed to the demise of the RCA Theremin as a manufactured item, a possible contributor may have been its high cost, in combination with the big stock market crash (
Black Thursday), a mere ten days after RCA's public debut of the instrument. Another significant miscalculation on the part of RCA was the perception that the theremin was easy to play.
Anyone who can carry a tune can play the Theremin! […] nothing more complicated than waving one's hands in the air!, boasted the advertising.
In reality, while anyone who moves their hands near the antennas of a theremin can cause it to alter its sounds, relatively few people possess the innate musicality required to play the instrument on pitch, let alone with nuance of expression. A good sense of relative pitch is a prerequisite to playing the instrument effectively, and as with any other instrument, practice is essential to a pleasing technique.
RCA ceased production of the theremin after a very limited pilot production run of only 500 instruments in total, making them among the rarest manufactured electronic devices of any kind. To put this in perspective, in 1932, the year after the last documented sale of a new RCA Theremin, RCA (as just one of many manufacturers) was producing 9,000 radios per day. To date, only approximately 112 surviving RCA Theremins from the sole original production of 500 are known to exist.
A non-technical explanation of the principle of operation is necessarily a simplification. To put it succinctly, a low-level electromagnetic field is generated within the circuits of the instrument. This field, which extends to an active distance of a few feet, emanates from the two antennas; the vertical pitch control rod on the top of the cabinet, and the horizontal volume control loop on the side. The electromagnetic fields are relatively weak; a tiny fraction of a mobile phone in use.
The theremin’s note is determined by a pair of nearly identical pitch circuits, or oscillators—one is connected to the pitch antenna and is variable, the other remains at a fixed frequency. Both are set at approximately 175 kilohertz which is in the radio frequency, or RF range. This is well below the AM radio band, but still about ten times beyond human hearing. When a performer places her hand within the pitch antenna’s field, her body capacitance causes only the variable oscillator’s frequency to shift. This shift is then blended with the fixed pitch oscillator’s set frequency. The like frequencies of the two pitch oscillators cancel each other out, leaving just the difference frequency which is well within the range of human hearing.
The theremin’s volume is determined by a proximity-controlled circuit which allows current to flow in the instrument's built-in audio amplifier, permitting a greater or lesser amount of the audible note to pass into the loudspeaker based on the position of the performer's other hand in relation to the volume antenna.
Leon Theremin's conception of his namesake included a repertoire of classical music selections. By the end of 1930, it had been heard on programs of the New York, Cleveland and Philadelphia symphony orchestras and a number of composers of prominence had written especially for the theremin. Also that year, a performance of ten theremins was demonstrated at Carnegie Hall as part of an avant-garde multimedia production.
In the mid 1940s, Hollywood composers discovered the theremin and began to arrange scores that included its haunting sounds to convey disturbed states of mind or establish suspense. Alfred Hitchcock's Spellbound (1945) used theremin extensively in its score. By the early 1950s, the sound of the theremin began to appear in science fiction films, most notably The Day the Earth Stood Still (1951).
By the 1960s, theremin sounds began to be heard in experimental and rock music. A popular misconception is that the Beach Boys used a theremin in their studio release of Good Vibrations. In reality, the eerie sound was produced by an
Tannerin, the creation of session musician Paul Tanner. The sound is nearly the same, but the electro-theremin is a contact instrument. The band Lothar and the Hand People used theremin, as well as Led Zeppelin's Jimmy Page. More recently, Yoko Ono has employed theremin, played by Pamelia Kursten.
For further reading, you may enjoy Albert Glinsky's superlative biography Theremin: Ether Music and Espionage.