Ondes Martenot

Left, the phase φ between the two oscillators, going round once per cycle of the note; its speed, Δ − K sin φ, is drawn around the circle. The pull slows it on one side and hurries it on the other, so a strong pull at a low note lingers and snaps round. Right, one cycle of what the drawer's timbres make of it, slowed down.

Each loudspeaker that is on, as the lines it rings at: the springs' modes (below the transition F_C they crowd toward it), the tam-tam's modes, denser the higher they go, and the palme's 24 strings, two chromatic octaves. A harmonic of the note that lands near a line sets it ringing.

A slide along the ribbon bends every harmonic together. With the diffuseurs on, lines stay behind after each note: the tam-tam's halo, the springs' chirps, the palme's strings.