This might be mixing 101 but I've messed this up more than once. If/when you're routing to a mixer, make sure you are receiving the benefit of stereo from your piano by setting each channel to mono within the mixer and then setting the balance for each channel to left and to right appropriately. If not, you'll be getting mono left and mono right coming out of both speakers and it will sound like a mess which you might not notice. Move your mixer sliders up and down to confirm that the sound is still not sounding in both speakers with one channel (left or right) turned all the way down. I have this routing saved in my mixer, Tascam 32, but if I forget to reload it then the CP1 sounds very uninspiring and I may not know why. If you aren't using a mixer then you won't have this issue.