The ondes Martenot, invented by Maurice Martenot, uses a keyboard and a sliding wire to control electronic pitch.
Maurice Martenot, a French cellist and radio operator, introduced the instrument in 1928. It generates electronic tones and gives the performer several ways to control pitch and expression. A conventional keyboard provides discrete notes, while a ring attached to a wire allows continuous gliding between pitches. A touch-sensitive control can shape dynamics and articulation.
The ondes Martenot became one of the earliest electronic instruments to enter serious concert music. Its expressive, voice-like sound appears in works by composers including Olivier Messiaen, who used it extensively in pieces such as the Turangalîla-Symphonie. Different speakers and resonators can further alter its color, including the distinctive resonating strings associated with some models.
It is often confused with the theremin because both can produce electronic glissandos. The theremin is played without physical contact using the performer's hands near antennas, whereas the ondes Martenot offers a keyboard and a physical wire interface.