Using mt32-pi with a hardware sequencer

[atoktoto]

I want to use mt32-pi as a synthesizer with a hardware midi sequencer.
Is there a way to configure the instruments accessible on each midi channel? As I understand there is a default configuration but can I overwrite it by editing a configuration file, using buttons or sending CC# values using rotary encoders on the sequencer?

[dwhinham]

I'm not sure what kind of sequencer you have, but you can use standard MIDI Program Change messages to configure the instruments available on each channel just like regular synth modules. Can your sequencer send those?

There is no way to set the startup instruments via config file at the moment, but you could easily create a .MID file that "sets up" mt32-pi with the instruments you want and play it before triggering the sequencer. You can also use custom SysEx messages to swap between MT-32 and SoundFont synthesizers; some MIDI controllers can be programmed to send these, or again, you can embed them into a MIDI file.

[atoktoto]

Thank you for your answer. The sequencer is: Arturia Keystep Pro and surprisingly its not capable of sending MIDI Program Change / Bank Change messages. It also does not pass them through.

I'm thinking about adding another box between the sequencer and mt32-pi but this makes it a little bit of a messy setup even if I skip the MIDI breakout stuff on the input.

[atoktoto]

Maybe I can use the i2c protocol used by MiSTer?

[dwhinham]

That is a very unfortunate limitation of the Arturia; some of the very cheapest MIDI controllers can send a PC with a button or combination.

The MiSTer protocol is extremely basic; you can't use it for PCs (or MIDI messages in general). It is a simple status register that reflects the user's synth/ROM preferences. MIDI is still done the usual way via UART on the MiSTer.

As an alternative to wiring things up, the next version of mt32-pi will support MIDI over the network (wifi/ethernet). You could send PCs easily using a computer and rtpMIDI on Windows/macOS built-in network MIDI/rtpmidid on Linux.

You can try a development build (e.g. https://github.com/dwhinham/mt32-pi/actions/runs/811150192) but I have not had any time to write documentation yet.

[atoktoto]

That is one amazing update you have there :D I'm still waiting for my raspberry. This might be the solution for me. I can use TouchDAW on Android to select the program.

Just to make sure, can it receive MIDI over USB and WiFi at the same time?

[dwhinham]

Yes, TouchDAW should work - though I think you'll still need a PC in the middle to act as the session host - mt32-pi can only be a "participant" at the moment.

Though you can use the network MIDI at the same time as USB/GPIO, yes. But if you are sending mixtures of note on/off events or parameters from both, you could end up with a mess as the messages could get interleaved, so you need to be careful.