I don't think I have explained he first question well.

This morning I fired up the Montage with the determination that I should be able to play the instrument in its multitimbral glory on this traditional day of sanctity.

I lay down the initial midi part (CFX+ fm). I'm happy. There are an additional 3 available parts I can assign.

To be clear, the "CFX + FM EP" Performance uses five Parts (1-5), meaning there are 11 PARTS available that you can assign!!! The Montage is sixteen Part multi-timbral - therefore if you use 5 PARTS to record a multi-Part sound, you are left with 11 single Parts that you can add.

There are several ways to view PARTS 9-16:
_ Hold [SHIFT] + [PERFORMANCE CONTROL] the button will flash during viewing the 9-16 Parts
_ If you press the [PART CONTROL] button, this turns the first two rows of right front panel buttons to PART SELECT [1]-[16] buttons. Press them directly to select your Part 1-16.
_ From the main PERFORMANCE (HOME) screen, touch "MIXING" in the first column to view the Montage's digital mixer. You can select to view PARTS 1-8 plus the AUDIO INPUTS or you can select to view all internal synth Parts 1-16. The view can be toggled from a box in the lower left of the mixer.

I assign an acoustic piano which fills the additional 3 parts. My problem is that now every other part I assign in the performance plays the initial midi data intended for the CFX paino. If as suggested I switch off 'Kbd Ctrl' on either the current part (accoustic paino) that I am playing or the first assigned instrument (CFX) then no sounds are heard. They are in effect muted and when I switch 'Kbd Ctrl' back on both instruments follow the original midi pattern I had played.

Again, you've misunderstood a couple of basic fundamentals of working with MONTAGE. First, if you wish to record and playback on multiple MIDI Channels, the MIDI I/O mode should be set "Multi". This is set in [UTILITY] > "Settings" > "Advanced" > MIDI I/O = Multi.

The KBD CTRL has to do with which Parts are under simultaneous control from the keyboard. Naturally when you initially played "CFX + FM EP" there were five green KBD CTRL icons. You've finished playing/recording that - turn them OFF. Light them for the new three Parts 6, 7 and 8... Now Parts 6, 7 and 8 are under your keyboard's control... It's that simple (and that complex).

Explanation
You have already selected one MULTI-Part Performance (CFX + FM EP) to play. This multi Part sound used five Parts, meaning, as I stated above, you have eleven single Parts to add additional instrument sounds. You've opted to play a second multi Part sound, okay, there should only be three green KBD CTRL buttons lit when you are playing it. (Unusual but, nothing prevents you from doing this... But you may find that you do not have the same control over these three new Parts as you would if you were playing them in their original location. (More on that later).

Not sure why in your example, you need a second acoustic piano, but the instrument you select, is really not important... What is important to understand is what KBD CTRL means. It is designed so you can play/control more than one Part slot at a time. In actual fact, you are wishing to play an eight Part multi-Part sound where Parts 1-4 are the CFX acoustic piano, Part 5 is the FM electric piano, and Parts 6-8 are a different acoustic piano... Those are your Multi-Parts. You need to program that as a single entity so that you Super Knob assignments are included. I'm not exactly sure why you would need a second acoustic piano but this would be a better approach to setting up... because you simply need to "control" all eight Parts as a single entity.

Then you could perform this single 8 Part sound as you require. You'll need to figure out what and when each different piano is to be playing -if you don't need them to play the exact same thing (layered). In order to have them play something different you will need to control which Parts are active.

But once you recorded your dual acoustic + FM electric instrument, you will still have eight more Parts available for Single Part sounds, 9-16.
But say you want to record a third or even a fourth Multi Part sound, you can by using the EXCHANGE function... But let's not go there just yet. I think you first have to clearly get what KBD CTRL is about, and how multiple Part sounds work with controllers. It is completely different from simply layering sounds on the same MIDI Channel.

You can (very much like in the Motif series) setup a multi Part Performance (there it was a maximum of four XF Parts) to record simultaneously, now it's eight PART. And you can add single Parts for the others. Now you can record eight Parts simultaneously and can add eight single Parts.

But since you're using a DAW, why not simply render as audio, your "CFX + FM EP" track. Then go back to Montage and add your other Multi Part Performance. At least until you master programming 8 Part Performances featuring three separate instrument sounds together, a better way to work is treat them and record them separately. If you just combine two multi Part Performances without a full understanding of what you are inheriting and not inheriting in terms of controllers, it can get confusing... I would recommend a different workflow.

I think it may be some problem in my setup. Is there an option on the Montage that could mean the individual parts are not treated like separate instruments and instead are automatically combined to create single performances. If so I guess I'm asking how do I turn that off. I think I'm having routing issues.

Again, typically, you can have one Multi Part Performance that is under KBD CTRL, it can be as few as two and as many as eight Parts. If you want to "merge" a second multi Part Performance, best know what the implications of that means to your ability to control them.

From what you describe you need to create a custom Performance that has the CFX acoustic (Parts 1-4) when the Super Knob is down, an FM EP (Part 5) when the Super Knob is turned up, and perhaps using a SCENE to work Mutes for you to brings in that second acoustic piano(?) that comes in and plays from Part 6-8). Then you can use Parts 9-16 as Single Part instruments.

Does the second multi Part sound you are merging use the Super Knob? Have you added control over these new three Parts so that they make sense with the five existing Parts? Or are you not respecting the multi Part control programming? (Very likely, you are not because you are unaware of what was originally programmed in that second merged Piano... This can mean you can inherit some unexpected things when you move a controller, or you might be missing some control assignments... in fact your "merged" multi Part may not behave the same as it does when it is played by itself... Just sayin'

Thanks BM, This is a lot of info! I will get my teeth into the above later and let you know how I get on.

The next series of articles will be Snorkeler level (stuff everyone should know) about building PERFORMANCES and using them in LIVE SETS. It can get complex, but only when you inherit some programming unknowingly... Or conversely, don't inherit some programming that you thought would come along. But once you get used to the different starting points, it's fairly smooth sailing.

Anyway, let us know.

It is plug and play, which doesn't have to mean you have to be mindless to use it. It simply means you have to find the level at which you float.

The connection is easy... One USB cable takes the place of 38 standard signal cables. Even those technically challenged can wire the USB connection.

For those technically challenged it defaults to a simple stereo record setup.
If the flexibility of the 32-in/6-out busing system is freightening, you don't have to go there. There is plenty to play with just using the regular stereo inputs and outputs.