I don't think the MODX can do what I'm trying to do, but I figured I'd better run it by the experts here before I give up and post it as an Ideascale suggestion...
Normally in Multi mode, if you have anything loaded into Part 4 of a Performance, the keyboard will also transmit note events on channel 4, unless you have used the Zone settings to have that part transmit on some other channel and not transmit on channel 4. So far so good, yes?
Okay, so now I set up a 4-Part Performance with the appropriate Zone settings so that I hear no internal sound on Part 4, all I hear is an external sound Part 4 is triggering from my iPad. That works fine.
But if I switch to another Performance which has an internal sound set for Part 4, the iPad sound is still being triggered because, as mentioned above, an internal Part 4 sound will, by default, also send MIDI note events out on channel 4.
1) Edit all the Performances that have 4-Part sounds so that Part 4 is set to not send MIDI. That's not really practical, I want to be able to call up any sound at any time, and I don't want to have to manually edit every 4-Part Performance that came on the board. Also, I may want to do the same thing with Part 3, using another iPad sound, and maybe even sometimes Part 2, so it just becomes increasingly impractical.
2) Change the board from Multi mode to Single mode. Now the board will only transmit on channel 1, even when I have sounds on Parts 2, 3, and 4. All I have to do is make sure the iPad is not set to respond to MIDI channel 1. This is workable. Now I should be able to have Performances with *either* internal OR external sounds on Parts 2, 3, and 4, and switch between them as much as I want, and I will only hear the internal sounds when I only want to hear internal sounds, and external sounds only when I want to hear external sounds. BUT... I may also sometimes want to independently trigger a MODX sound from some other keyboard. For that to work, I need the board to be in Multi mode. I don't really want to give up that capability. So this solution has a pretty significant trade-off.
3) Put my iPad sound on some channel in the 9-16 range. Now I can be sure that no MODX Performance consisting of internal sounds will ever inadvertently trigger an external sound, since when it comes to internal sounds, MODX Performances are limited to parts/channels 1 through 8. So there will be no conflict as I switch back and forth between Performances that use any combination of Internal and External sounds. Seems perfect, right? BUT... as soon as I put even a single external sound on any part between 9 and 16, I lose seamless sound switching of the internal sounds, even if I'm only switching between what are, internally, single part sounds. That's a pretty unfortunate trade-off.
I guess what I'm looking for is for the board to be able to be set for Multi mode when it comes to receiving MIDI, but Single mode when it comes to sending MIDI. Or alteratively, some new setting that simply globally turns off transmission of MIDI notes on all Parts except when specifically enabled for a Part via the Zone Master function (which would be better, because it would free up all channels, even channel 1, which even Single mode wouldn't do). I don't suppose maybe there is such a setting and I missed it?
Is there any other way to accomplish my goal here? Or is this a job for Ideascale?