Auto channel on the Elektron boxes is their technique for controlling MIDI input and passing it on to whichever of the tracks is currently selected on the machine. So, in my example, if the S37 sends MIDI data on channel 9 and the Octatrack’s auto channel is channel 9, the Octatrack will pass this data on to whichever of the eight tracks is currently selected. This way, you can play any of the eight tracks from the S37 keyboard simply by selecting the applicable track on the OT.

Regarding the use of channel 9 in your set up, I recommended in my post that you switch off the MIDI channels for the individual tracks on your AR to begin with, on the assumption that you will use the internal sequencer of the AR to trigger its sounds.

With the settings I listed (AUDIO NOTE IN = ‘On’), the OT will receive MIDI notes from the S37. I suggested that you set both TRANSPORT RECEIVE and CLOCK RECEIVE to ‘off’ because the OT will be the master in the system.