Quick answer
The Ondes Martenot are one of the first electronic musical instruments, invented by Maurice Martenot in 1928. They produce sound with electronic oscillators and are controlled with a keyboard and a sliding ring on a ribbon, giving continuous glissandi and a very expressive vibrato. Their ghostly, vocal timbre is a cousin of the theremin, but with far more precise tuning.
What are the Ondes Martenot?
The Ondes Martenot (French for “Martenot waves”) are a monophonic electronic instrument (one note at a time) invented by the French musician and engineer Maurice Martenot and unveiled in Paris in 1928. It is one of the absolute pioneers of electronic music, contemporary with the theremin (1920) and predating the synthesizers that would arrive decades later.
Unlike a piano or a guitar, where the sound comes from a string or a hammer, the Ondes Martenot generate sound with electronic oscillators (originally, vacuum tubes). That gives it a pure, continuous, “bodiless” timbre that is instantly recognisable: many describe it as a distant human voice or an otherworldly sound.
The instrument has been officially taught at the Paris Conservatoire since the mid-20th century, which explains why so many French scores include it. It is both a piece of technological history and a fully active concert instrument.
If you are fascinated by instruments that break the rules, the Ondes Martenot share that “charming rarity” with the theremin, the stylophone or the otamatone itself: expressive electronic instruments played in ways nothing else quite matches.
How it works: keyboard, ribbon and the intensity drawer
What makes the Ondes Martenot unique is its control system, played with both hands at once:
The keyboard and the ribbon (right hand)
The right hand has two ways to play. It can press a traditional keyboard (au clavier mode) that, additionally, is mounted so each key can be moved sideways to produce a natural vibrato with the finger. Or it can use the ribbon mode (au ruban): the player slides a metal ring (the bague) worn on the finger along a taut ribbon parallel to the keyboard, producing continuous glissandi with no steps, like a tuned siren.
The intensity key (left hand)
The left hand controls the touche d’intensité, a pressure-sensitive key in a small drawer on the left. It does not produce notes: it shapes the volume and attack of every sound in real time. Thanks to it, the player can make a note appear from nothing, swell, vibrate and fade with extraordinary dynamic control. This “breathing” of the sound is the big difference from the theremin.
The diffusers
Sound comes out through special loudspeakers (diffuseurs). The most famous is the Palme: a lyre-shaped diffuser with sympathetic strings that add a harmonic halo to the timbre. Others use a metal gong or a plate that adds natural reverberation. Switching diffusers completely changes the instrument’s colour.
Ondes Martenot vs theremin: what's the difference?
It is the inevitable comparison, since both were born in the 1920s and share that ethereal timbre. But they are played in very different ways:
| Aspect | Ondes Martenot | Theremin |
|---|---|---|
| Year | 1928 | 1920 |
| Pitch control | Keyboard + ring on ribbon | No contact (antennas) |
| Tuning precision | High | Very hard |
| Dynamics control | Intensity key | Volume antenna |
| Learning curve | Medium-high | High |
In short: the theremin is visually more spectacular (played in mid-air), but the Ondes Martenot offer far more control by combining a physical keyboard, a ribbon for glissandi and a dedicated dynamics key. If you want to start with an electronic instrument in this style without spending a fortune, read our theremin guide or discover the stylophone.
History: from 1928 to Radiohead
Maurice Martenot, a cellist and radio operator during World War I, was fascinated by the pure sounds of radio valves. That experience led him to design an instrument that combined the expressiveness of an acoustic instrument with the novelty of electronic sound. He patented it and unveiled it in 1928.
Composer Olivier Messiaen was its great champion: he gave it a central role in his monumental Turangalîla-Symphonie (1948), where the Ondes Martenot provide that soaring timbre that sweeps over the whole orchestra. Since then, dozens of 20th-century composers have written for the instrument.
Cinema also adopted it early: its “ghostly” timbre was perfect for the sci-fi and horror films of the 1950s and 1960s. And in the 21st century it has enjoyed a second youth thanks to Jonny Greenwood, guitarist of Radiohead, who has used it on the band’s records and in his film scores, bringing the instrument back into popular culture.
Can you play or buy one today?
Original instruments are extremely rare and expensive, essentially museum and collector’s pieces. That is why modern recreations have appeared:
- Physical replicas such as the Ondéa, which reproduce the keyboard, ribbon and intensity key with current electronics.
- Software emulations (VST/AU plugins) that recreate its sound for computer-based music production.
- Ribbon-style controllers and modern synthesizers with a touch strip that allow Martenot-style glissandi.
If what draws you is experimenting with an expressive electronic sound without spending much, there are far more accessible instruments to get started: the theremin, the stylophone or the wonderfully silly otamatone share that “quirky electronic instrument” spirit at a beginner-friendly price.
Frequently asked questions
What are the Ondes Martenot?
One of the first electronic instruments, invented by Maurice Martenot in 1928. They generate sound with electronic oscillators and are controlled with a keyboard and a sliding ring on a ribbon, giving glissandi and a very expressive vibrato.
How do they differ from the theremin?
The theremin is played without touching it, moving the hands near two antennas, and is very hard to tune. The Ondes Martenot have a keyboard and ribbon, so tuning is far more precise, plus a dedicated key for volume and attack control.
How are they played?
With both hands: the right presses the keyboard or slides the ring along the ribbon; the left shapes volume and attack with the intensity key. Special diffusers (like the Palme, with resonant strings) colour the timbre.
Where have they been used?
In classical music (Messiaen's Turangalîla-Symphonie), film scores and contemporary pop-rock, especially with Jonny Greenwood (Radiohead). They are taught at the Paris Conservatoire.
Can you buy one today?
Originals are museum pieces. Modern recreations exist (like the Ondéa) and software emulations. To start with an expressive, cheap electronic sound, the theremin, stylophone or otamatone are accessible alternatives.
Why do they sound so ghostly?
They combine pure electronic oscillators with very fine control of vibrato and dynamics, producing a continuous, vocal, sliding sound with no percussive attack. That's why sci-fi and horror cinema used it so much.