The synth voice
Pulse width and sync
Two ways to change a tone's colour without a filter.
Pulse width
Narrow the pulse and listen as harmonics drop out.
Try it
- Hear the square at 50%
- Narrow the pulse below 20%
- Let an LFO move the width
Two classic ways to change an oscillator's colour without a filter: narrowing a pulse, and syncing one oscillator to another.
At 50% the pulse is a square. Narrow it and the sound thins and turns reedy, as different harmonics drop out.
A pulse of width w cancels every harmonic n where n × w is a whole number. At 50% that is every even harmonic: the square. At 25%, every fourth harmonic goes.
Moving the width with a slow LFO (pulse-width modulation) gives the chorus-like movement of many classic string and pad patches.
Hard sync
One oscillator restarts another: the tone moves, the note stays.
Try it
- Play the synced sound
- Sweep the synced oscillator
One oscillator is forced to restart its cycle every time another one does. Sweep the second one's pitch and a new peak in the tone moves, while the note stays put.
Practice and check: 10 questions
Answer from memory. It is what makes it stick.