Hi @Patrick,
I can’t say anything about the IAC-driver or Ableton, maybe this is helpful. but concerning to your 1. question:
As soon as you’ll specify and fire up a midi command in Sonic Pi, this will get send by default on all channels; you can restrict this to a specific channel (such as channel: 3). You can see this in the cue log window (if you don’t see that, go to “Preferences > Editor” and check “Show Cue Log”). Make sure you do see these messages and also: Check “Preferences > I/O > Midi Ports”; you should see Midi in/Midi out ports. If not, there is something wrong and Midi won’t work. This is - as far as I know - also where you should see the IAC-entry (I think that’s kind of a virtual midi device on Mac OSX (or are you on Windows??))
The cue messages will contain something like this (this is also the format to address a specific device)
# first part of midi cue message send to a hardware device recognised by Sonic Pi
/midi/arturia_beatstep_midi_1/3/1/
# if you send midi to specific devices you can also use wild
# cards if port/channel is not important
/midi/arturia_beatstep_midi_1/*/*/
# the general format is:
/midi/[device]/[port]/[channel]/
I think for a start it should be sufficient if you configured Ableton to listen to ‘Midi Through’ and then just send some Midi via Sonic Pi.
There is certainly much more to be said about this subject.
- Check out @robin.newman’s blog; he has worked quite a lot with Sonic Pi and Midi and documented lots of thinks in a very helpful way.
- Do also check this forum for e. g. “Midi” or “IAC”, as you will probably find more information about this (e. g. I found the afore-mentioned blog article about the IAC-driver via search here).
Hope, that helps a bit.
Cheers
Martin