There are a few threads regarding phase issue with keyboards through the PAS in Stereo.

Yamaha corrected this issue with the CP series by including a mono Piano. I guess the output summing for the keyboard isn't electronically correct. And Yamaha did view it as enough of an issue to rectify it on the Sample level. The T3 NOT having the same further goes to prove Yamaha's difficulty in viewing these Keyboards as actually used out side the home....LOL http://bose.infopop.cc/eve/forums/a/tpc/f/6806048934/m/9976080565 http://bose.infopop.cc/eve/forums/a/tpc/f/8766055944/m/6951046942?r=6951046942