I used to play with hardware MIDI devices - at first without a PC (just a Q80 sequencer as the "hub") and then with a PC. MIDI isn't technically tied to a medi

I used to play with hardware MIDI devices - at first without a PC (just a Q80 sequencer as the "hub") and then with a PC. MIDI isn't technically tied to a medium, but the only notion of addressing are MIDI channels (at least the classic v1 from the 80s) - you can target messages to any channel 1-16. It's up to you to set your devices to listen on the right channels. For example: If you have a keyboard set to transmit on channel 5, and two modules listening on channel 5, they'll both play when you press a key on your keyboard. Classic MIDI with the DIN plugs was a RS-232 wire protocol - devices typically had an IN, OUT and often a THRU port to forward all received MIDIs (some forwarded everything out of the OUT port). Latency was a problem with the older devices, but there were "MIDI hubs" that fixed that, and when computers started getting MIDI hardware (Atari ST had it built-in, and ISA MIDI cards for the PC were a thing), it got better. So as long as devices are connected via some serial-like communication method and can forward to each other, MIDI will work over it if all the devices involved can use it. I'm not too familiar with everything Bluetooth but I know that Bluetooth virtual serial/COM ports are a thing. MIDI speeds are low (33Kbit/sec). Classic MIDI will work just fine over that, without any additional engineering, as long as all nodes agree to send and receive MIDI over it.