vault / music / synthesis.md
FM synthesis
One oscillator wobbles another’s pitch fast enough that you hear new partials instead of vibrato. The carrier sets the base pitch, the modulator sets the brightness, and the index sets how much: low index is a round tone, high index goes metallic. Failure symptoms: harsh and buzzy means too much index, mud means the modulator sits too low, thin means the ratio is too simple. Start at a 2:1 ratio with the index low, raise it until it gets interesting, then stop.