Waveforms

An oscillator repeats a shape hundreds of times a second. How fast it repeats is the pitch. What the shape looks like decides the timbre — because every non-sine shape is secretly a stack of sine waves called harmonics.

A sine has no harmonics: soft, round, a little flute-like. A triangle adds a few odd harmonics that fade quickly — mellow. A square has every odd harmonic — hollow, woody, think clarinet or chiptune. A saw has every harmonic, odd and even — the brightest, buzziest, most filter-friendly shape.

Subtractive synthesis starts bright and removes what you do not want. A saw gives the filter the most material to carve, which is why so many basses, leads and pads begin there.

Pulse width matters too: narrowing a square into a thin pulse changes its harmonic recipe and makes it nasal. Slowly sweeping the width (PWM) gives that classic chorus-like shimmer.