Greetings,
As I understand it, the Akai APC40 MkII uses MIDI CH 1-9, and that for LED feedback, a velocity value is sent back to the controller on the same channel / note that triggers the MIDI Shortcut.
I was messing around with my MIDI Fighter 3D which I have set to start at MIDI CH 10. When I create a MIDI Shortcut and send a velocity value back out, it is also triggering LEDs on the APC40.
MIDI Fighter: CH 10, Note D#2 with the shortcut sending data out
APC40: CH 1, Note D#2 is reacting to that outbound feedback data, meant to be on CH 10.
Kendall