inSync reader S.C. asks: "Is there some way my drummer can control the sequencer tempo while playing live?"

If the drummer is required to set the tempo, a sequencer with TAP SYNC (a.k.a. Tap Tempo) can be used. The drummer can set the tempo by tapping on the button and then can follow the sequence as normal. Some sequencers are able to listen to the output of a kick or snare drum channel and derive a tempo from that in real time. The problem with that is the drummer has to be almost as solid as the machine. Any abrupt deviation in tempo could cause a train wreck because the sequencer may not be able to respond as "musically" as a real musician. Furthermore, the input to the sequencer has to be rock solid and the sensitivity set perfectly in order to prevent false triggers and other anomalies from confusing the sequencer. Aphex used to make a box called a Studio Clock that did this conversion fairly well and would output MIDI clock (see WFTD archive MIDI Clock) to any sequencer.

Still the best way is to have the drummer lock in to a click track (4 beats of count-in is usually sufficient) through either the drum monitor or headphones and play with the click and sequence during playback. You really want to have the drummer getting a full mix of the sequence so he isn't thrown off by that guitarist who is falling behind the beat or the singer that just started the second verse 8 bars too late.