[H1Supreme]

Depends on how you want to utilize it. If you want to connect it to a computer as a MIDI device, you'll have to use an Rpi4 or one of the Pi Zero's. The Pi's < 4 can't go into "gadget mode". I bought a new v4 for this exact reason.

The RtMidi library is probably your best bet for getting started. I found the ALSA library to suit my workflow a bit better, but the setup is pretty obtuse. RtMidi is much more user friendly in that regard.

Also, look into implementing the Ableton Link library. It runs over your network, and is honestly astounding how well it sync's devices.

[woudsma]

Ideally I'd sync it with Ableton's clock. I'm using Ableton only for tempo and multitrack recording. Maybe this is achievable without the RPi being a MIDI device? Sending messages over the network, like GuitarEffects which uses WebSockets. My RPi 2 doesn't support gadget mode (I should probably start looking for a RPi 4).

I'm currently using an Elektron Digitakt to sequence my analog gear - it's great - but unfortunately the DT is limited to 8 MIDI tracks with only 1 LFO per MIDI track to automate MIDI CC data. I'd love a Cirklon Sequentix but the waitlist is just too long (3 years atm, arghh).

I wonder if I can hook up something like a Midiface 16x16 (https://miditech.de/en/portfolio/midiface-16x16/) to the RPi. The Midiface is Class Compliant so maybe the RPi can use it natively..(?) I'm a bit worried about performance though.

Thanks for your suggestions, I'm going to look into them!

[riceart]

Can you readily get an rpi4 anywhere?

The Odroid C4 you can actually get is an alternative with 4 USB ports and an OTG that is gadget capable. Unlike older models, mainline Linux support is decent.