The 'reverb tail' of a drum sound panned to A will be audible out of B, so you should not use a reverb program.

Sounds panned to C&D will be audible through A&B if the PAN 3 and PAN 4 parameters are not set to 'OFF'.

If you wish to process the C&D panned sounds, use the PARALLEL effects algorithm.

Steve Martin
Ward Music Ltd.