I'm not sure what Bill's goals are. The BK-9 lacks built-in speakers. If it's truly a room-sized gig, then a BK-5 or E-A7 could be the answer. But with only 12 watts of amplification and no built-in subwoofer, for anything larger he would need an external amp anyway. As you pointed out, the BK-9 is remarkably light for a semi-pro action 76-key synth.