Source waveform sets harmonic complexity in a ladder from sine (pure) to noise (harsh)

The choice of oscillator waveform sets the baseline harmonic content before any filtering. The ladder from fewest to most harmonics runs: sine (one partial, pure/hollow) → triangle (odd harmonics, soft) → square/pulse (odd harmonics, woody/hollow) → sawtooth (all harmonics, bright/full/buzzy) → noise (all frequencies, harsh/airy). More harmonics equals richer or harsher. Filtering removes harmonics from this baseline while FM and saturation add them. Choosing the starting waveform is therefore the first harmonic decision in voice design: a dark, warm voice starts with a sine or triangle; a bright, aggressive voice starts with a saw.

Examples

A sine at 220Hz sounds hollow and pure. A square wave sounds woody because it carries only odd harmonics. A saw sounds bright and buzzy because it carries all harmonics.

Assessment

Order sine, saw, square, triangle, noise from fewest to most harmonics. For each, name one musical use where that harmonic content is appropriate.