chorus gain-in gain-out <delay decay speed depth -s|-t>

Chorus resembles an echo effect with a short delay, but whereas with echo the delay is constant, with chorus, it is varied using sinusoidal or triangular modulation. The modulation depth defines the range the modulated delay is played before or after the delay. Hence the delayed sound will sound slower or faster, that is the delayed sound tuned around the original one, like in a chorus where some vocals are slightly off key.

Each four-tuple parameter delay, decay, speed and depth gives the delay in milliseconds and the decay (relative to gain-in) with a modulation speed in Hz using depth in milliseconds. The modulation is either sinusoidal (-s) or triangular (-t). Gain-out is the volume of the output.

A typical delay is around 40ms to 60ms; the modulation speed is best near 0.25Hz and the modulation depth around 2ms. For example, a single delay:

chorus 0.7 0.9 55 0.4 0.25 2 -t

Two delays of the original samples:

chorus 0.6 0.9 50 0.4 0.25 2 -t 60 0.32 0.4 1.3 -s

A fuller sounding chorus (with three additional delays):

chorus 0.5 0.9 50 0.4 0.25 2 -t 60 0.32 0.4 2.3 -t 40 0.3 0.3 1.3 -s