Right now, they only play * waves (using Web Audio API)
* frequency: frequency in Hz
* type: "sine", "square", "triangle", "sawtooth"
* end: "linear" for linear fade over length, "exponential" for exponential fade over length, anything else for the wave to stop abruptly after length (fades start immediately)
* length: duration of the sound
Laetitia (O-01-67)