I think you have a typo or two in your original question - but understand the gist of it.

Quick and dirty:

If you are always using Part 1 and Part 2 on your MODX as slaves to the MX - then you could have a Performance with the volume/level of Parts 1&2 to be at zero so you cannot hear anything from MODX even though technically these two Parts are still being commanded by MX to play.

Not-so-quick Not-so-dirty:

There's not a way to change the input MIDI channel on MODX -unless- you use single-channel or hybrid modes. In this case, you have a bit more flexibility since Parts 1-8 (with keyboard control=ON) can be set to a single MIDI receive channel (send too - but it's MIDI receive that is of consequence here).

In which case, you would use Zone Master + Part Zone to force your MODX out of single or hybrid mode for some Performances and some Performances you would not have any Part Zone set which would have your single or hybrid mode work (in other words, not defeated).

In all cases, you would have Zone Master turned on.

This would be handled in one of two ways:

1) MX sends, to MODX, on MIDI channel that is NOT 1 or 2. Say it ONLY sends on 8. And your single/hybrid-channel mode MIDI send/receive channel is set to 8. Then you would want your MODX to not defeat single/hybrid mode when the MX is controlling MODX Part(s) and you would want to defeat single/hybrid mode when you do not want MX to control MODX Part(s)

or

2) MX send, to MODX, on MIDI channels 1 and or 2. When you want to "disconnect" the MODX from MX's MIDI - you make sure single/hybrid mode is NOT defeated and set the MIDI send/receive channel for single (or hybrid) mode to something other than 1 or 2. Set it to 8 for example. Then, on MX - configure to always send on 8. Again, MODX is set to single or hybrid mode. The send/receive channel in this example is 8. When I want to "disconnect" MODX from MX - I would make sure that at least one Part on MODX has Part Zone control turned on. This defeats the single or hybrid mode and sets the keyboard to multi-channel mode. Now Part 1 will MIDI receive on MIDI channel 1 and Part 2 will MIDI receive on MIDI channel 2. Since your MX is configured to send on Part 8 - neither of these Parts will be commanded by MX to sound.

Thanks for your reply
I try to say it as clearly as possible. I use the MX as master and the MODX as slave. MX Midi OUT -> MODX Midi IN

In MODX I make all performances. In some songs I want to use the MX as master and in others I don't. I have to turn this on or off globally now on the MX or MODX. My question is can you also do this as a performance parameter in the MODX

In other words, I want to know if I can specify from the MODX whether Part 1 and 2 can be played from the MX or not.

“MODX as slave” - doesn’t get to determine anything.
If MODX is master it can determine what happens in MX (as slave).
If MX is “master” (the keys you are physically playing) then it is in control - it does not have an official Master Keyboard mode, like the “Zone Master” function found in the MODX.

It is still very unclear (for me) the way you are writing this. Try adding the model numbers and perhaps a reason why you are setting up this way - it makes it clearer… for example, if the MX you have is the MX88 it immediately becomes clear why you would want to physically play on those keys, versus a MODX6 or MODX7.

But if your MX is a 49 or 61, and your MODX is an 8, you can see why one would want to provide a completely different solution… and those are not the only scenarios. Give us a reason why the MX (which does not have a Master Keyboard function) is being used as a system ‘master’.

Please refer to which set of keys you physically want play…
Do you ever want to physically play the MODX keys, or are you always going to physically play on the MX keys?

In other words, I want to know if I can specify from the MODX whether Part 1 and 2 can be played from the MX or not.

I can read this sentence many times and still not understand what you are asking… both synths have a Part 1 and a Part 2

Thank you for replying again,

I own a MODX7 and a MX61 🙂
In my new band she plays the very old song - I will Survival - by Gloria Gaynor. I want to set the sounds as follows.

The MODX7: Split with left Piano and right split strings.
The MX61: Only Brass

In my current setup with the MX61 as Master I play on the MX61 the Brass (from the MODX7 Parts 1 and 2) . On the MODX I play the piano (part 3) and the strings (part 4). So all sounds come from the MODX7 as one Performance. The master volume on the MX61 is set to 0.

This all works okay. The problem arises when I don't want to use the MX61 as a master for a next song, but want to use the sounds of the MX61 itself. So both synthesizers separately. Playing on their own tone generator. When I switch performance the MX61 is still set to play the part 1 and part 2 from the MODX7 and the volume is still set to 0.

My question is, if it is possible to control midi from a performance instead globally from the utilty menu.

Excuse my ignorance and thank you for your patience, but this is very new to me. And I'm trying my best english. I am Dutch :p

I tried something what could work but do not know it is the best solution.
I kept the MX61 as Master.

On the MODX I tested a performance with three parts. I can play part 1 and 2 on the MODX7 and part 3 on the MX61 using Part Select and then channel 3. Only one part at the time. On the MODX7 is Keyboard Control for part 3 set to off.

I did also a test with part 1 and 2 on the MX61. Then I can layer and split the to parts. On the MODX7 Keyboard Control = off for both parts.

The disadvantage is that I cannot use the sounds of the MX61. I have set LocalCtrl=off