Meet the Theremin

The Theremin was invented in 1919 by a Russian physicist named Lev Termen (his name was later changed to Leon Theremin). Today, this marvelous instrument is once again in the musical spotlight.
Besides looking like no other instrument, the Theremin is unique in that it is played without being touched. Two antennas protrude from the Theremin - one controlling pitch, and the other controlling volume. As a hand approaches the vertical antenna, the pitch gets higher. Approaching the horizontal antenna makes the volume softer. Because there is no physical contact with the instrument, playing the Theremin requires precise skill and perfect pitch.

In the early 1920's, Leon Theremin came to the United States to promote his invention. He was given a studio to work in, and he trained several musicians to help bring the Theremin into the public eye. Then, in 1938, Leon Theremin was taken back to the Soviet Union by force, leaving behind his studio, friends, business, and his wife. After a stay in a prison camp, Leon Theremin reportedly worked for the KGB designing among other things, the "bug" and methods for cleaning up noisy audio recordings.

The Theremin in Music & Film

Originally, the Theremin was intended to replace entire orchestras with its "music from the ether." While that never quite happened, it has been used in many recordings over the years. During the 60's and 70's, bands such as Lothar and the Hand People, the Bonzo Doo Dah Dog Band, and Led Zeppelin brought the Theremin into the public eye for a short time. Then, the Theremin slipped back into obscurity until the recent revival of the 1990s. Today, lots of bands use theremins, though few in a musical context.
The spooky sound of the Theremin was used in several movie soundtracks during the 1950's and 1960's. It provided background mood music for such sci-fi classics as The Day the Earth Stood Still and It Came From Outer Space, as well as thrillers such as Spellbound and The Lost Weekend.
In 1993, Steven M. Martin produced a documentary entitled Theremin: An Electronic Odyssey. This incredible film provides an in-depth look into the history of the instrument and its inventor. The film features rare footage and interviews with music industry legends such as Robert Moog, Todd Rundgren, and Brian Wilson as well as Prof. Leon Theremin himself!

What say Wikipedia ?

The Theremin is one of the earliest electronic musical instruments, and the first musical instrument played without being touched (originally pronounced [ˈteremin] but often anglicized as IPA: ˈθɛrəmɪn, theramin, or thereminvox, it is also known as an aetherphone.) It was invented by Russian inventor Lev Theremin (Russian: Лев Сергеевич Термен) in 1919,[citation needed]. The controlling section is usually two metal antennas to sense the position of the player's hands. These control audio oscillator(s) for frequency with one hand, and volume with the other. The electric signals from the Theremin are amplified and sent to a loudspeaker. The Theremin is a quintephone.
To play, the player moves his hands around the antennas, controlling frequency (pitch) and amplitude (volume). The Theremin is associated with "alien", surreal, and eerie-sounding portamento, glissando, tremolo, and vibrato sounds, due to its use in film soundtracks such as Spellbound, The Lost Weekend, Ed Wood, Mars Attacks! (together with Ondes-Martenot and pre-recorded Theremin samples) and The Day the Earth Stood Still. Theremins are also used in art music (especially avant-garde and 20th century "new music") and in popular music genres such as rock and pop. John Otway regularly uses a Theremin in his performances, Jean Michel Jarre also used it on his album Oxygene.

Other electronic instruments, such as the Ondes-Martenot also use two heterodyning oscillators, but the Ondes-Martenot is touched while played.

The Theremin was originally the product of Russian government-sponsored research into proximity sensors. The instrument was invented by a young Russian physicist named Lev Sergeivich Termen (known in the West as Léon Theremin) in 1919, after the outbreak of the Russian civil war. After positive reviews at Moscow electronics conferences, Theremin demonstrated the device to Bolshevik leader Vladimir Lenin. Lenin was so impressed with the device that he began taking lessons in playing it, commissioned six hundred of the instruments for distribution throughout the Soviet Union, and sent Theremin on a trip around the world to demonstrate the latest Soviet technology and the invention of electronic music. After a lengthy tour of Europe, during which time he demonstrated his invention to packed houses, Theremin found his way to America, where he patented his invention in 1928. Subsequently, Theremin granted commercial production rights to RCA.
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. In 1938, Theremin left the United States, though the circumstances related to his departure are in dispute. Many accounts claim he was taken from his New York City apartment by Soviet agents, returned to the USSR and made to work in a sharashka. However, Albert Glinsky's 2000 biography Theremin: Ether Music and Espionage suggests he fled to escape crushing personal debts, and was subsequently caught up in Stalin's political purges. In any case, Theremin did not return to the United States until 1991.

A modern Moog theremin

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. However, a niche interest in the Theremin persisted, mostly among electronics enthusiasts and kit-building hobbyists. One of these electronics enthusiasts, Robert Moog, began building theremins in the 1950s, while he was a high-school student. Moog subsequently published a number of articles about building theremins, and sold Theremin kits which were intended to be assembled by the customer. Moog credited what he learned from the experience as leading directly to his groundbreaking synthesizer, the Minimoog.

Since the release of the film Theremin: An Electronic Odyssey in 1994 (one year after the death of Léon Theremin), the instrument has enjoyed a resurgence in interest and has become more widely used by contemporary musicians. Even though many Theremin sounds can be approximated on many modern synthesizers, some musicians continue to appreciate the expressiveness, novelty and uniqueness of using an actual theremin. The film itself has garnered excellent reviews.

Today Moog Music, Dan Burns of soundslikeburns.com Chuck Collins of theremaniacs.com Wavefront Technologies and Kees Enkelaar manufacture performance-quality theremins. Theremin kit building remains popular with electronics buffs; kits are available from Moog Music, Theremaniacs, Harrison Instruments, PAiA Electronics, and Jaycar. On the other end of the scale, many low-end Theremins, some of which have only pitch control, are offered online and offline, sometimes advertised as toys.

Operating principles

A Theremin is unique among musical instruments in that it is performed without being touched by the operator. The musician stands in front of the instrument and moves his or her hands in the proximity of two metal antennas. The distance from one antenna determines frequency (pitch), and the distance from the other controls amplitude (volume). Most frequently, the right hand controls the pitch and the left controls the volume, although some performers reverse this arrangement. Additionally, some theremins use a volume dial and have only one antenna.
A Theremin uses the heterodyne principle to generate an audio signal. The instrument's circuitry includes two radio frequency oscillators. One oscillator operates at a fixed frequency. The other is a variable frequency oscillator, the frequency of which is controlled by the performer's distance from the frequency control antenna. The performer's hand acts as the grounded plate (the performer's body being the connection to ground) of a variable capacitor in an L-C (inductance-capacitance) circuit. The difference between the frequencies of the two oscillators at each moment generates a beat frequency in the audio frequency range, resulting in audio signals that are amplified and sent to a loudspeaker.
To control volume, the performer's hand acts as the grounded plate of another variable capacitor. In this case, the capacitor detunes another L-C circuit, which affects the amplifier circuit. The distance between the performer's hand and the volume control antenna determines the capacitor's value, which regulates the theremin's volume.

Performance technique

Easy to learn but notoriously difficult to master, Theremin performance presents two challenges: reliable control of the instrument's pitch with no guidance (no keys, valves, frets, or finger-board positions), and minimizing undesired portamento that is inherent in the instrument's microtonal design.
Pitch control is challenging because, like a violin or trombone, a Theremin generates tones of any pitch throughout its entire range, including those that lie between the conventional notes. In the case of some string instruments, the range is divided along the strings by use of length divisions . By contrast, in the case of the theremin, the entire range of pitches is controlled by the distance of the performer's hand or fingers to the pitch antenna in mid-air. Precise control of manual position coupled with an excellent sense of pitch is required, since the electromagnetic field around the antenna tends to change slowly over time, resulting in changing positions of individual pitches.
Also, the theremin's continuous range of pitches lends itself to glissando playing, which can be inappropriate to the piece being performed. Skilled performers, through rapid and exact hand movements, minimize undesired portamento and glissando to play individual notes and can even achieve staccato effects. Small and rapid movements of the hands can create tremolo or vibrato effects.

Although pitch is governed primarily by the distance of the performer's hand to the pitch antenna, most precision thereminists augment their playing techniques with a system called "aerial fingering", largely devised by Clara Rockmore and subsequently extended by Lydia Kavina. It employs specific hand and finger positions to alter slightly the amount of capacitance relative to the pitch antenna to produce small changes in tone quickly and in a manner that can be reliably reproduced.

An alternate and controversial "hands on" technique is called "angling" in which the pitch control hand is actually set on the top of the Theremin which violates the "no touch" creed of traditionalists. It employs changing the angle of the hand and fingers to alter the pitch and repositioning the hand if the pitch interval is too large for "angling". By touching the instrument, the effect on pitch of extraneous movement is dampened. This permits the use of steady pitches without vibrato and without remaining perfectly still.

Equally important in Theremin articulation is the use of the volume control antenna. Unlike touched instruments, where simply halting play or damping a resonator silences the instrument, the thereminist must "play the rests, as well as the notes", as Ms. Rockmore observes. Although volume technique is less developed than pitch technique, some thereminists have worked to extend it, especially Pamelia Kurstin's "walking bass" technique.

Skilled players who overcome these challenges by a precisely controlled combination of movements can achieve complex and expressive performances, and thus realize a theremin's potential.

Some thereminists in the avant-garde openly rebel against developing any formalized technique, viewing it as imposing traditional limitations on an instrument that is inherently free form. These players choose to develop their own highly personalized techniques. The question of the relative value of formal technique versus free form performances is hotly debated among thereminists. Theremin artist Anthony Ptak uses antenna interference in live performance.