PSR SX900 owner here, Hammond sounds are just so-so. I'd like to add either a Roland VR-09B or a Hammond XK1. Not being a MIDI smart person, can either one of these keyboards be hooked up so their sound comes through the PSR speakers? I have no desire to bring the Roland/Hammond sounds down to the PSR keyboard; I'd like to be able to jump up to the new keyboard at any old time. I know I can do it if I use my PA, but I'm talking about using it at home without the PA.