How can I use the VB-101's stereo out?
The VB-101's stereo out allows you several things:
1) The Spatial effect allows for turning mono input into stereo output sound, so you can gain in spatial presence. This is notably quite pleasant for playing with headphones.
2) It is possible to get processed sound out on one side, and non-processed sound out on the other, for later use.
3) Even with mono out and the same signal on both sides, the double output allows you to feed two circuits — typically one for FOH and one for monitoring.
4) Finally, the VB-101's firmware Version 3 allows for double stereo miking, which allows you to simulate simultaneous stereo miking of two cabs with two mics.