If I switch from a performance with multiple parts to another with fewer parts then when I edit the performance I can still see the extra parts from the first performance when I page through them. Is this the intended behaviour? It's very confusing to see data that isn't actually being used.

That sounds correct... the *selected* Performance will sound when you play the keys, its data will only occupy Part slots where it has data. The previous data still in the unused slots remains in the buffer.

In spite of what you are expecting (?) this behavior sounds completely normal. When you switch to “FM Marimba” (1 Part), the Parts of “FM Wave Dreams” that are not directly occupied by your new selection remain in the Part slot Buffer... inactive.

It will always be true... if you wish to add a Part to “FM Marimba” (or any Performance) you must first tap the “+” icon on the Home screen. This operation is called “Merge”... and it literally attaches a set of Part parameters — it creates an active Part slot.

“FM Marimba” being a Single Part program only carries data for a single Part, in this case Part #1. The data packet for a single Part Performance is smaller than a Performance with more Parts. It simply has no data and therefore no reason to disturb the unused buffers. It simply occupies the Part slot(s) it requires.

When you tap ”+” on the Performance Home screen, this act clears that temporary Buffer and literally, adds an active set of parameters. This allows you to reconfigure that slot with your new selection’s settings.

While each Performance has 16 potential Parts, the system does not store the data in those empty slots as apart of the Performance. It only uses the *active* Parts - it only archives the *active* data. To activate a Part you must start from Home by “+” adding it, first.

Extra Credit: Where does the parameter data go?
Each of the 16 Parts has an edit buffer for A/B type edit/compare, and there is a recall buffer where the last edit (previous) that you performed remains, in tact. This system, allows you great flexibility when editing and creating your own data. Not only is the original data of the active Part available, the entire previously edited Part is recallable. You needn’t concern yourself with unused settings —they are inactive.

When using a Part slot to control an external device Out via MIDI, you must first activate the Part slot, tap ”+” to Add a set of Part parameters... then if you want to dedicate this Part slot as *external” you must turn the INT SW (Internal Switch) to Off, and select a MIDI Transmit Channel to Output from that Part slot, now referred to as a “Zone”. Point being: the way to active a slot is always “+” on the Performance Home screen... this literally adds whatever you do with that slot to the data package - otherwise the system efficiently does not include it in its ‘footprint’. (It has nothing to overwrite it, and no need to disturb it).

Exprected Behaviour
1. Any parts not included in the performance should be cleared to 'No Assign' state.

Inactive (unused) data, should be of no concern... to clear it always:
Tap ”+” to add a Part slot.
Doing this adds the data of the Part slot you select — called “Performance Merge” — you are literally appending the selection onto the current Performance.

Hope that helps. Thanks for the question.

Thanks for the detailed reply, especially the extra credit info. 😀

To me "switching" a Performance means performing an action that will clear out everything in the edit buffer and replace it with a new Performance. So there would be no residue left over from the 1st Performance before the "switch".

One way to switch would be to press a different slot in live set to "switch" performances. You'd see nothing "left over" after the switch unless, certainly, the two Performances were saved with related data in the PART slots.

... or if you press [PERFORMANCE] (HOME) - just as a paranoid step to place your MODX in a known state - then press [CATEGORY SEARCH] and select a new Performance. This would replace the entire Performance with a new one.

I've got a feeling you're not doing what I would call "switching" Performances if you see residue. Performance merge or PART replace would both have the kind of behavior you mention - but neither is what I'd consider to be "switching".

I gave detailed reproduction steps. But just as another test:

1. Turn on your MODX. The default performance on mine is still set to CFX + FM Piano (or something like that)
2. Go to [LIVE SET]
3. Select "FM Marimba" from the FM presets page.
4. Hit [EXIT]
5. Edit Part 1 (the only part).
6. Select Part 2 and it is still set to "FM Piano". But it's not part of the performance.

I gave a detailed explanation. Here it is again...

“CFX + FM EP 2” = occupies 2 Parts: CFX acoustic in Part 1, FM EP in Part 2.
You recall “FM Marimba” = 1 Part

That one Part occupies just 1 Part slot, therefore any data occupying Parts 2 through 16 is inactive.
The “FM Marimba” needs to activate just one slot, slot #1.

If a “+” occupies the slot, that slot is like yesterday’s lesson on the blackboard... it is old news, inactive,
The “+” that appears on the HOME screen deactivates all data in that slot... there is only one way to overwrite what remains in that deactivated slot, and that is to tap “+” to merge a new program into it, or choose another Performance that needs that slot.

A Performance can contain as few as one and as many as 16 Parts. When you change Performances it occupies the number of slots equal to the number of programmed Parts... all unoccupied slots are deactivated by the system and are headed by the “+” icon... signifying that the current Performance has no meaningful data for that slot.

Bad Mister, no need to explain further. I understood your initial response. I was responding to Jason above.

Oh. I see.