One of my favorite rack mount synths is the Roland MKS-70. A 12-voice DCO polysynth made in 1986-1989 that is update-able with Frederic Vecoven’s mods. It’s basically the same as a Roland JX-10 Super JX which has been been used on countless soundtracks including Twin Peaks.
Lately, I’ve been obsessively trying to figure out how best to send MIDI control change information to the synth’s parameters. I’ve done this successfully with sysex, and with the learn function of a BCR-2000 knob box, but now I’m trying to put the newer CC message functionality of the Vecoven firmware (v.3.15) to use. My goal is to create a template in supercollider to access all of the synths parameters, so that I can easily access them to generate random patches, and to sequence parameter changes. In the process I’ve been learning the deeper side of MIDI as implemented in commercially produced hardware – including MSB Most significant bit, LSB Least significant bit, NRPN Non-registered parameter number – and beefing up a bit on sysex and Pbinds.
Thankfully, I have some heads helping me out on the Supercollider Users forum:
https://www.listarc.bham.ac.uk/lists/sc-users/msg63961.html
*Along the way, I came across a forum post where someone posted the MIDI spec – keep that around for your reference.