Chorus

Applies chorus effect to the selected part of an audio file.

Parameter	Description
Delay Rate	Rate of delay. Varies from 0 (there isn't delay) to 100 (delay is 20 ms).
Mix Depth	The dry is the volume of the input signal and the wet is the volume of the delayed signal, in percent. Varies from 0 to 100. If Mix Depth = 0 result signal isn't contain delayed signal. If Mix Depth = 100 result signal isn't contain input signal. Other values of Mix Depth are combination of the dry and the wet (wet = 100 - dry).
Feed Back Gain	Feed Back Gain sets how much delay is feed back to the input. Varies from 0 to 100.
Sweep Depth	The sweep depth determines how wide the sweep is in terms of delay time, in percent. Varies from 0 (no effect) to 100 (maximal effect).
Sweep Rate	This parameter refers to the frequency of flanging. Varies from 0 to 100, in percent.
Sweep Phase	Phase of delay, in radian.

Tip:

See also: Apply a Special Effect or Filter
The Chorus differs from the Flanger in only a couple of ways. One difference is the amount of delay that is used. The delay times in a Chorus are larger than in a Flanger, usually somewhere between 20 ms. and 30 ms. (the Flanger's delay usually ranges from 1 ms. to 10 ms.) This longer delay doesn't produce the characteristic sweeping sound of the Flanger. The Chorus also differs from the Flanger in that there is generally no feedback used.
For more information about chorus effect see: http://www.harmony-central.com/Effects/Articles/Chorus/