Have you ever used a stereo chorus on a bass sound and ended up with a muddy bottom end swimming all over the place? Bass Chorus can avoid that problem by separating the bass and treble frequencies, where you set the cutoff frequency. The effect is only applied to the treble portion, which is then mixed back with the bass for output.
It's not just a chorus - it's a true thru-zero flanger. It's not just for bass - it's flexible and full-featured. It can create a huge, wide bass sound without sacrificing punch and focus.