The chorus unit on your Woovebox allows for thickening up a sound, or even add an "overflying fighter jet"-like quality to a sound.
9/A1/Ch.SP controls the speed with which the chorus bounces between 10/A2/Ch.t1 chorus time1 and 11/A3/Ch.t2 chorus time 2.
There are two modes for the chorus slectable via 12/A4/Ch.AL; a Juno-like stereo chorus that thickens the sound, or a "phaser"-like sound (comb filter) that subtracts a time-offset version of the original signal.