Peter, don't use the Yamaha mono sum output..Try the left and right outputs into your Roland amp [2 channels]..I think you will hear a difference..

Fran,

I tried doing what you suggested, still sounds tinny to me.
Playing this keyboard with the Bose L1 sounded pretty good, but the piano still wasn't right for me and it's a little pricey.

Ian,

I'm going to check out your suggestion using two smaller speakers. I didn't think it would work because of the size of the speakers, but maybe I'm wrong.
Do you use a PSR3000 with your Yamaha set up?

Donny,

That little Mackie looks interesting. I'll check that out too.

Thanks guys for you imput.

Peter