Unison

In music, unison means several players on the same note. Synths borrowed the word for stacking copies of one sound. It works like detune with more copies: where detune sets two oscillators a few cents apart, a unison section plays several copies of each note and spreads their pitches across a detune range.

A unison section usually has three controls:

• Voices: how many copies play per note. Two or three sound thick; seven sound like a wall.
• Detune: how far apart the copies are pitched. Too little and it sounds like one saw, too much and a held chord goes out of tune.
• Spread (also Width or Stereo): how far the copies are panned left and right.

The best-known unison sound is the supersaw. Roland’s JP-8000, from the late 1990s, had a waveform by that name that resembles seven sawtooth waves detuned against each other, and it became a signature sound of trance. On a synth with unison, a saw wave at 7 voices, detune about a quarter of the way up and spread near full gets close.

On an analog polysynth, a unison mode often puts all the synth’s voices on a single note for a huge mono lead, so you can only play one note at a time. On software synths the cost is processing power: 7-voice unison on a four-note chord runs 28 oscillators at once, which makes it a good first thing to turn down when a project starts to crackle.

Keep the lowest bass layer out of wide unison, since heavily spread copies can cancel on a mono speaker. How to make a synth sound bigger walks through a full supersaw build, and the house pluck in how to make a pluck synth can use 5 to 7 unison voices.