The theremin (/ˈθɛrəmɪn/; originally known as the ætherphone, etherphone, thereminophone[2] or termenvox/thereminvox) is an electronic musical instrument controlled without physical contact by the performer (who is known as a thereminist).

The theremin has been used in movie soundtracks such as Miklós Rózsa's Spellbound and The Lost Weekend, Bernard Herrmann's The Day the Earth Stood Still, and Justin Hurwitz's First Man, as well as in theme songs for television shows such as the ITV drama Midsomer Murders and the Disney+ series Loki, the latter composed by Natalie Holt.

Although the RCA Thereminvox (released immediately following the Stock Market Crash of 1929) was not a commercial success, it fascinated audiences in America and abroad.

Clara Rockmore, a well-known thereminist, toured to wide acclaim, performing a classical repertoire in concert halls around the United States, often sharing the bill with Paul Robeson.

Joseph Whiteley (1894–1984) performed under the stage name Musaire and his 1930 RCA Theremin can be seen, played and heard at the Musical Museum, Brentford, England.

Many accounts claim he was taken from his New York City apartment by NKVD agents (preceding the KGB),[10] taken back to the Soviet Union and made to work in a sharashka laboratory prison camp at Magadan, Siberia.

In his 2000 biography of the inventor, Theremin: Ether Music and Espionage, Albert Glinsky suggested he had fled to escape crushing personal debts, and was then caught up in Stalin's political purges.

[11] After a flurry of interest in America following the end of the Second World War, the theremin soon fell into disuse with serious musicians, mainly because newer electronic instruments were introduced that were easier to play.

)[12][13] Since the release of the film Theremin: An Electronic Odyssey in 1993, the instrument has enjoyed a resurgence in interest and has become more widely used by contemporary musicians.

The performer's hand has significant body capacitance, and thus can be treated as the grounded plate of a variable capacitor in an L-C (inductance-capacitance) circuit, which is part of the oscillator and determines its frequency.

Using optimized pitch field linearisation, circuits can be made where a change in capacitance between the performer and the instrument in the order of 0.01 picofarads produces a full octave of frequency shift.

In the earliest theremins, the radio frequency plate current of the oscillator is picked up by another winding and used to power the filament of another diode-connected triode, which thus acts as a variable conductance element changing the output amplitude.

[27] Other concert composers who have written for theremin include Bohuslav Martinů,[28] Percy Grainger,[28] Christian Wolff,[28] Joseph Schillinger,[28] Moritz Eggert,[29] Iraida Yusupova,[29] Jorge Antunes,[28] Vladimir Komarov,[28] Anis Fuleihan,[30][31] and Fazıl Say.

[34] Maverick composer Percy Grainger chose to use ensembles of four or six theremins (in preference to a string quartet) for his two earliest experimental Free Music compositions (1935–1937) because of the instrument's complete 'gliding' freedom of pitch.

[35][36] Musician Jean-Michel Jarre used the instrument in his concerts Oxygène in Moscow in 1997 and Space of Freedom[37] in Gdańsk in 2005, providing also a short history of Leon Theremin's life.

The five-piece Spaghetti Western Orchestra use a theremin as a replacement for Edda Dell'Orso's vocals in their interpretation of Ennio Morricone's "Once Upon a Time in the West".

[43] The theremin concerto "Dancefloor With Pulsing" by the French composer Regis Campo was written for Carolina Eyck and premiered with the Brussels Philharmonic in 2018.

[48] In response to requests by the band, Moog Music began producing its own brand of ribbon-controlled instruments which would mimic the sound of a theremin.

[51] Tesla guitarist Frank Hannon used a theremin in the band's song "Edison's Medicine" from the 1991 album Psychotic Supper.

[54][55] Although credited with a "Thereman" [sic] on the track "Mysterons" from the album Dummy, Portishead actually used a monophonic synthesizer to achieve theremin-like effects, as confirmed by Adrian Utley, who is credited as playing the instrument;[56] on the songs "Half Day Closing", "Humming", "The Rip", and "Machine Gun" he has actually used a custom-made theremin.

[58] When Simon and Garfunkel performed their song "The Boxer" during a concert at Madison Square Garden in December 2003, they utilized a theremin.

While the theremin was not widely used in classical music performances, the instrument found great success in many motion pictures, notably, Spellbound, The Red House, The Lost Weekend (all three of which were written by Miklós Rózsa, the composer who pioneered the use of the instrument in Hollywood scores), The Spiral Staircase, Rocketship X-M, The Day the Earth Stood Still, The Thing from Another World, Castle in the Air, and The Ten Commandments.

More recent appearances in film scores include Monster House, Ed Wood, The Machinist[62] and The Electrical Life of Louis Wain[63] (2021), (last three featuring Lydia Kavina), as well as First Man (2018).

A theremin was not used for the soundtrack of Forbidden Planet, for which Bebe and Louis Barron built disposable oscillator circuits and a ring modulator to create the electronic tonalities used in the film.

[69] The First Theremin Concert for Extraterrestrials was the world's first musical METI broadcast dispatched from the Evpatoria deep-space communications complex in Crimea,[80] and was sent seven years before NASA's Across the Universe message.