In my case, I singing through a Digitech Vocalist VR and firing that into the keyboard's Line-In. Then everything comes out of the keyboard's right and left outputs and goes into channels #1 and #2 of the Bose. Both channels are set at #57 presets, which works well with the PSR-3000 and Tyros.

Be sure to set the volumes per the instruction manual--this is very important and provides you with the best quality sounds. As for the remote, I set both the high and mid at approximately the 2 O'Clock position and the bass at the 12 O'Clock position on both channels. The main volume control rarely gets above the 10 O'clock position.

Good Luck,

Gary