Hi Tim

I think you really need to check out the following link at buy.com for the Yamaha YST MS50. It is marked down to a measley $36.49 after rebate.

If you type MS50 into search here at SynthZone, you'll see all the guys talking about how much they are enjoying theirs and how big a room and how many people in the audience it will cover.

I see Richard Peck even has two sets and loves the sound. He also has a unique system for set up. The two smaller speakers are mounted on top of his sub woofer with velcro. So no need to mess around with attaching those brackets to the keyboard itself.
http://www.buy.com/retail/product.asp?sku=10270535&loc=1989

Best
Scott Langholff