Disklavier

Hi folks:

For those of us who don��t have a Yamaha amp and speaker set included/factory installed with our Pro pianos, I��m looking for clever suggestions for pumping out some real sound out of either the DKC-850 controller (2 options for audio out on the back) or out of the silent piano/headset control box on the Pro.   It seems that the output in either choice is a very weak signal.  Even hooked up to a set of M-Audio AV40 powered monitor speakers, it just can��t keep up with the monster sound of the C5 grand (even with the lid down).  

I could put a pre-amp inline, but all the additional wires and possible line interference just starts to make the piano look more like it��s part of a recording studio/computer room instead of a beautiful acoustic instrument �� in my living room.  Plus I��m hesitant to attach any additional equipment to the piano because of possible heat gain and sympathetic vibrations (Yamaha��s recommended MSP3 powered speakers are too big to fit under even a 6��7 grand).   

Anyone come up with a cool sounding/looking solution?  

Thanks!