Synthesis · glossary
Waveform
Also called wave shape, sine wave, sawtooth wave, square wave, triangle wave
A waveform is the shape of a sound wave drawn over time; for a repeating wave, the shape of one cycle. On a synth it is the oscillator's basic shape, usually sine, triangle, sawtooth, square or pulse, and it decides which overtones a note carries and how loud each one is.
Draw a sound wave against time and the line you get is its waveform. On a synth the word usually means the oscillator’s shape, picked from a short menu or a slider. Each shape carries a different mix of harmonics, the quieter tones stacked above the note you play at whole-number multiples of its frequency, and that mix is why a sine and a saw on the same C3 sound nothing alike.
| Waveform | Harmonics | Sounds like |
|---|---|---|
| Sine | None | Pure, a soft whistle or hum |
| Triangle | Odd ones, fading fast | Soft, close to a flute |
| Sawtooth | All of them | Bright and buzzy |
| Square | Odd ones only | Hollow, like a low clarinet |
| Pulse | Depends on width | Thin and nasal when narrow |
The numbers make it concrete. Play A2 (110 Hz) on a sawtooth and it contains 110, 220, 330 and 440 Hz and on up, each harmonic quieter than the one below it. A square on the same note skips the even ones: 110, 330, 550, 770 Hz. Those missing harmonics are why the square sounds hollow next to the saw.
The waveform also decides what a filter has to work with. A low-pass filter can only take harmonics away, so a sine gives it nothing to remove and a saw or square gives it plenty. That is why classic synth brass and strings usually start on a sawtooth. Pulse waves have a width you can move while a note plays, covered under pulse width modulation.
In Gelato Synth, the Osc A page has a wave preview and a Shape slider that morphs from sine through triangle, saw and square to pulse, and a live oscilloscope draws the wave you hear. Synth waveforms explained goes through each shape and which to pick for bass, leads and pads.
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