Chorus

How a few milliseconds of modulated delay create width, and how rate and depth change what you hear.

Related

DelayBusElectric guitar

The question

Chorus sounds like width, so it is often filed as a space effect. It really works through a few milliseconds of time wobble, running a signal against a delayed copy and creating tiny differences in pitch and phase.

How it works

The input splits into a dry path and a copy delayed by 15 to 35 ms, with the delay time modulated by a 0.1 to 3 Hz LFO. A shorter delay raises pitch slightly and a longer one lowers it, and summing the two paths creates comb filtering. Multi-voice chorus uses several LFOs at different phases so the wobble is not uniform. More wet signal weakens the direct sound.

Settings and what you hear

Slow and shallow reads as double tracking, good on vocals and strings. Fast and deep approaches vibrato, and a piano starts to sound out of tune. Stereo mode splits the paths left and right for instant width; low frequencies spread apart unless they are kept mono.

What to listen for

Hold a long note on a clean electric guitar, first dry, then with chorus, and notice the slight pitch movement and the difference between sides. Move down to the low register and hear whether it starts to lose focus.

Common misconceptions

That chorus is reverb; that more voices mean more thickness; that heavy use on bass is safe without a mono check.

Sources

• Udo Zölzer, DAFX — Digital Audio Effects, modulation chapter — background checked, not quoted
• Sound On Sound, chorus and vibrato explained — typical rates and depths checked, not quoted

Used for fact-checking only; all prose is original.