Flange is an audio effect caused by mixing the original audio with a copy that is delayed by a varying amount that cycles over time. The frequency of the copy is also offset by an amount related to the delay. Chorus uses a larger delay, to make one voice or instrument sound like many.
The default settings for the Flange & Chorus effect are for flange. To create a chorus result, use values something like the following: 40 for Voice Separation Time (or higher for a greater chorus result), 4 for Voices, 0.1 for Modulation Rate, 50% for Modulation Depth, and 90 for Voice Phase Change, with Stereo Voices selected.
Voice Separation Time The time in milliseconds that separates each voice. Each voice is a delayed version of the original sound. Use values of 6 or lower for flange, and higher values for chorus.
Voices The number of voices in the processed (wet) audio.
Modulation Rate The rate in Hz at which the modulation cycles.
Modulation Depth The amount of modulation.
Voice Phase Change The modulation phase difference in degrees between each subsequent voice. Divide 360 by the number of voices to find the optimum value.
Invert Phase Inverts the phase of the processed (wet) audio, emphasizing more of the high frequencies; not inverting the phase emphasizes more of the low frequencies.
Stereo Voices Alternates assignment of voices to one of the two channels so that the first voice appears in the left channel, the second in the right channel, the third in the left, and so on. To hear stereo voices, preview or render in stereo.
Dry Out, Wet Out The amounts of the original (dry) sound and delayed (wet) sound in the final output. Values of 50% are commonly used.