I gig with a single Motion Sound KT-80 (was $399 when I bought it, it's up to $575 or so now....go figure). It's 100 watts and has been fine for events with up to 100-150 people so far. I've used it with my PSR-630, then the 2000, and now the 3000, and the sound is excellent, to my ears. It's 30 pounds and very easy to transport.