Reading some of these posts I have one thought to add:

It's all very noble to worry about what the audience hears but IMHO the most important audience is the player. I have to enjoy what I hear and get the most direct benefit from the sound... that's a lot of why I play. I'm not going to get hung up on whether that couple on the back of the room are getting the full benefit of the stereo separation. Often I go further by combining the internal speakers of my keyboard with my Motion Sound KP-200s behind me for a full surround-sound experience. The audience gets an acceptably good sound and a happy performer on stage.

Stereo 4 life.