The instrument in the corner of the room

The Ondes Martenot is not a synthesizer, and the fastest way to make it sound like one is to patch it like one. This recipe assembles the four objects that make up the actual instrument — voice, key, and a loudspeaker with a body — and then spends most of its length on the part that is not a setting at all: what your two hands do.

Everything measured here is borrowed from the instrument that is not a synthesizer and loudspeakers you can play, which in turn cite the circuit paper (Najnudel, Hélie, Roze & Boutin, IEEE/ACM TASLP 28, 2020) and the intensity-key measurement (Quartier et al., Acta Acustica 101(2), 2015).

The chain

[ribbon signal] ──▶ tap.ondes~ ──▶ tap.palme~ ──▶ out
[key signal]    ──▶     ▲              (or tap.metallique~)

Two signals in, one instrument out. That is the whole rig, and the temptation to put things between the stages should be resisted until you have played it as it stands — the voice and the diffuseur were designed to be adjacent, and every stage you insert is a stage the real instrument does not have.

The voice

Start there and change exactly one thing at a time, because most of these are citations rather than tastes and the object will tell you when you have left the instrument behind.

The two that are genuinely yours: keyplacement 1 moves the key in front of the valves, so hard presses get dirty as well as loud — worth about 0.09 of total harmonic content at a half-press, and it is the single change that most makes the object feel like a synthesizer rather than an ondes. polarity -1 flips which side of the waveform the preamplifier bends, worth about 0.12. Try both; keep whichever suits the piece.

depth below 1 is the cheapest real timbre move in the object. At 0.4 the envelope never closes and the tone thins toward a sinusoid — the closest thing here to a "register", and it is a physical mismatch between two oscillators rather than an invented control.

The hands

This is the recipe.

The ribbon is linear in semitones, because the circuit paper's Eq. 7 makes it so. That single fact is why an ondes glissando sounds like an ondes glissando: a hand moving at constant speed produces a constant-rate glide, not the accelerating swoop a linear-in-Hz control gives you. So drive ribbon with something that moves linearly in semitones over time:

line~ 0. 36. 4000   ──▶ tap.ondes~ left inlet

Three octaves in four seconds, and it will sound even the whole way. Build your phrases the same way — line~ or a slow sig~ ramp per note, never a quantized step unless you specifically want the instrument to sound wrong. Nothing here rounds to a semitone, and that is deliberate.

The key is the dynamics, and it starts silent. Roughly the bottom 45 % of the travel makes no sound at all. That is the key's own first phase, the elastic strip bending before it reaches the powder bag, and it is why the instrument attacks so sharply: the whole 50 dB lives in the 4.5 mm right after the silence. Practically:

• Drive key from a pedal, a fader, or a line~ — anything continuous.
• Expect nothing below about 0.45. If you want the note to speak the instant your controller leaves zero, rescale: scale 0. 1. 0.45 1.. Do that only if you want to give up the attack, because that dead travel is what lets you place an entrance to the millisecond.
• The curve steepens through the middle and flattens at the top. Crescendos therefore want a decelerating controller move, not a linear one — which is exactly the feedback a player's finger gets from the real spring.

Play them together. The ribbon without the key is a test tone; the key without the ribbon is a volume pedal. The instrument is the two hands, and ondes_ribbon.wav in the render set exists to demonstrate what that sounds like when both are moving.

The loudspeaker, which is an instrument too

tap.palme~ is the default answer. Twelve strings on a board, and they sustain what the voice has already stopped playing:

tuning 1 puts the harmonic series on the root instead: the board then answers only what belongs to that key, which turns a chromatic line into something that blooms on some notes and stays dry on others. Use it when the piece really is in one key, and hear it as a compositional decision rather than a preset.

Watch the level. Twelve resonant loops add up, and a driven board can be a great deal louder than what went into it — level is there for that, and it is the one control on these objects you will need to touch first.

tap.metallique~ is the other cabinet: eight plate modes rather than twelve strings, so it colours instead of harmonizing. @pitch 180 @decay 6 @tilt 0.8 @brightness 1. @mix 50 is the gong. Push drive to 3 with asymmetry 0.5 and the distortion happens before the plate, because that is where the transducer is — a distorted waveform ringing a gong, not a distorted gong. It is not subtle and it is the most distinctive sound in the family.

What each ingredient buys, in order

1. tap.ondes~ with both hands moving. Everything else is optional. A static ribbon and a static key is a demo, not an instrument.
2. The diffuseur. The voice alone is thin on purpose — it is a valve preamplifier output, and it was never meant to be heard without a body after it.
3. depth. The one timbre control that costs nothing and is physical.
4. keyplacement / polarity. Real, measured, and yours to choose.
5. power. Measured at 0.003 of total harmonic content. Last.

When to leave the recipe

• You want the waveform registers. The real instrument has switchable timbres — creux, gambe, nasillard and the rest. They are not here, and they are not here on purpose: no source obtained describes their filter shapes, and inventing them is the one thing these objects will not do. If you need those colours, put a filter after tap.ondes~ and call it your filter, not Martenot's.
• You want polyphony. The instrument is monophonic and so is this. Two tap.ondes~ in parallel is a duet, not a chord — which is how ondes ensembles actually worked, so it is not a bad answer.
• You want the diffuseurs on something else. Take them. A guitar into tap.palme~ is the best argument for shipping them standalone, and nothing about them needs the voice in front.
• You want tap.triode~ on its own. It is a published valve stage and it works on anything: @tube 2 @stage 2 @drive 6 is the 2A3 power stage used for something it was never in this instrument for.