doesn't it depend on the synth you are using? when i was sending midi to an outside roland synthesizer the reverb was generated by the synth in response to the signal from BIAB and currently the soft synth i am using responds to the midi message from BIAB or RB using the reverb capability within the synth itself.

just as BIAB makes no sound itself - simply sending the midi info to the synth - it has no reverb capability apart from sending midi reverb instructions to the synth.

what synth are you using?