ondes Martenot
An early electronic instrument using a keyboard and a sliding ring to produce expressive, wavering tones.
In Depth
Invented in 1928 by French cellist Maurice Martenot, the ondes Martenot produces sound through vacuum tube oscillators controlled by a keyboard and a sliding metal ring worn on the finger. The ring, attached to a wire running along the keyboard, allows continuous pitch control similar to a theremin but with the visual reference of piano keys. Multiple loudspeakers, including one with a resonating gong, create its distinctive timbre. Olivier Messiaen championed the instrument, writing for it in his monumental Turangalîla-Symphonie (1948) and Fête des belles eaux (1937) for six ondes Martenot. The instrument also appears in works by Honegger, Milhaud, and Varèse, and has been used extensively in film scores. Radiohead guitarist Jonny Greenwood has brought renewed attention to the instrument, using it both in the band and in his film scores.
Only around 300 ondes Martenot were ever built, and surviving instruments are maintained by a small group of dedicated technicians in France.