Hello, all. I’m trying to remotely switch which instrument/kit plays on a track by recalling different Scenes from an external sequencer, using the CCs listed in the official MIDI CC reference table (CC82/85 = Scene, CC83/84 = Previous/Next scene). I’ve run into two behaviors I can’t fully explain and wanted to check if others have seen the same.
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OP-XY (firmware version: 1.1.33
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External sequencer: OXI One MK2, connected via TRS
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Testing done entirely in Arrange mode (not Song mode)
Issue 1 — CC85 (Scene, immediate) value-to-scene mapping shifts depending on total scene count
Per the official reference table, CC85 is documented as a fixed 0-based index (value 0 = Scene 1, value 1 = Scene 2, etc.), independent of how many scenes exist.
In practice, across three separate tests (adding one scene/instrument at a time, N = total scenes at time of test), the actual mapping I observed consistently follows:
CC85 value = (Scene number − 2) mod N
| N | Value 0 | Value 1 | Value 2 | Value 3 | Value 4 |
|---|---|---|---|---|---|
| 3 | Scene 2 | Scene 3 | Scene 1 | — | — |
| 4 | Scene 2 | Scene 3 | Scene 4 | Scene 1 | — |
| 5 | Scene 2 | Scene 3 | Scene 4 | Scene 5 | Scene 1 |
12/12 data points across three scene counts matched this formula exactly. This means any fixed value-to-scene mapping breaks every time a scene is added or removed — not ideal for a live/performance workflow driven entirely by an external sequencer.
Reproduction steps:
- Build Scene 1 (e.g. drums), select it (Shift + accidental key 1).
- Build Scene 2 (e.g. synth key), select it (Shift + 2).
- Build Scene 3 (e.g. synth bass), select it (Shift + 3).
- From an external sequencer, send CC85 with values 0, 1, 2 in turn and note which scene/instrument plays.
- Add a 4th and 5th scene the same way and repeat.
Issue 2 — CC83/84 (Previous/Next scene) don’t seem to latch; the scene reverts unless the CC value is held
Separately, I tried using CC83 (Previous scene) / CC84 (Next scene) instead, since they don’t depend on scene count. These didn’t appear to do anything while OP-XY was in Arrange mode — possibly because, per user reports elsewhere, the physical Plus/Minus buttons this CC pair likely mirrors only function in Song mode, not Arrange mode.
When I did get a response from these CCs, the scene change only held for as long as the CC value stayed non-zero — sending a single “spike” (e.g. 127 then immediately back to 0) reverted to the previous scene almost immediately, rather than latching until the next explicit change. I haven’t been able to confirm from the documentation whether this is intended (momentary) behavior or something else.
Questions:
- Has anyone else observed the scene-count-dependent offset with CC85?
- Do CC83/84 require Song mode specifically, and if so, do they behave the same way (latching vs momentary) there as CC85 does in Arrange mode?
- Is there a more reliable way to remotely address a specific Scene by number from an external sequencer, without depending on total scene count?