Lee,
First check the manual to see what controllers or system exclusive it takes to do all you want. Don't know about the ones you have, but some of the Novation MIDI controller kbds do support sending of Sys. Exclusive.

Why not do it the way I have...mount the controller under the Audya..VERY close with the Audya keys hanging over a bit just like the Organs used to do it. It is cool!
You actually want the Audya to set on the MIDI controller (use rubber pads) and will need to support the rear of Audya somehow.

If you do it right you may love it.
Use the MIDI controller just for lower and maye upper 2 or 3 (I'm speaking Yamaha terms here). Then, the left of split on the MIDI controller is LH voice including chords (probably still have the Audya LH working as well) to the righ of split...you have your second voice sound by just playing the lower keyboard anytime you want.

Use all the normal Audya controls not any of the ones on the MIDI controler (except maybe pitch & Mod wheels).
You could also have a MIDI setup in the Audya & controller for Piano, Vibes set of percussion etc on entire lower.

Just a thought...and I have done it on T2 and PA2...so it does work.

Lee S.

[This message has been edited by leeboy (edited 09-13-2010).]