Thanks! And it does help, partly....what I'm really looking for is the ability to have, say, a string or organ sound on the Nord, and to pull that up on slider 1 to layer with the Px's piano sound, over the whole range of the keyboard. If I turn the generator out to OFF, I can play the Nord but obviously not the Px's piano. Another wrinkle seems to be that, while I can raise or lower the volume of the Nord with the slider configured in this way, when I pull the slider all the way down (000) I still hear output from the Nord, albeit lower in volume. Any ideas?