Mike, you beat me to it. I was about to post on Marty's technique.
Each instrumentalist has a single C9 on his/her music stand that in sequenced to the beat track of his overall sequence for that particular song, so the live musicians stay on track with the sequenced display lights.
He has been doing live music on weekends during his display season at least going back as far as 2004 that I am aware of..
A great way to sync live music to sequenced lighting!