Maurice Martenot a Cellist and radio Telegraphist, met the Russian designer of the Theremin, Leon Termen in 1923, this meeting lead him to design an instrument based on Termens ideas, the first model, the “Ondes-Martenot” was patented on the 2nd of April 1928 under the name “Perfectionnements aux instruments de musique électriques” (improvements to electronic music instruments). His aim was to produce a versatile electronic instrument that was immediately familiar to orchestral musicians. The first versions bore little resemblance to the later production models: consisteing of two table mounted units controlled by a performer who manipulated a string atached to a finger ring (using the bodies capacitance to control the sound characteristics in a manner very similar to the Theremin) this device was later incorporated as a fingerboard strip above the keyboard. Later versions used a standard keyboard.
The Ondes-Martenot became the first succesfull electronic instrument and the only one of its generation that is still used by orchestras today, Martenot himself became, 20 years after its invention, a professor at the Paris Conservatoire teaching lessons in the Ondes-Martenot.
The Ondes-Martenot’s success was the Theremins loss, although both used the vacuum tube oscillator as a sound source and were both monophonic, where the Theremin had a sliding scale and no fixed preset notes the Ondes-Martenot had a keyboard and a strip control for glissando and vibrato and an appearance that was familiar to any keyboard player.
The instrument also had a bank of expression keys that allowed the player to change the timbre and character of the sounds. A later (1938) version of the instrument featured microtonal tuning as specified by the Hindu poet Rabindranath Tagore and the musician Alain Danielou.
The Ondes-Martenot was quickly accepted and eventually had a wide repetoire, works were written for the instrument by composers such as Edgard Varèse, Olivier Messian (The “Turangalîla Symphonie” and “Trois Petites Liturgies de la Presence Divine” amongst others ),Darius Milhaud , Arthur Honegger, Maurice Jarre, Jolivet and Koechlin.