Rebuilding a 1990s MIDI Studio

Retro MIDI Engineering

This is a work log for the MIDI studio I have been assembling: the star topology rigs you used to see in 1992, rebuilt with one modern addition — a headless Debian box that acts as sequencer, SysEx librarian, video capture station and MIDI-over-IP endpoint.

The rig

  • MIDI fabric: MOTU Timepiece II, 8 in / 8 out, configured from the front panel (more on that below)
  • Sequencers: Atari STE running Cubase, Amiga 500 running OctaMED, and the Debian box running Qtractor
  • Sound modules: E-mu Ultra Proteus, Roland JV-2080, Roland SC-88 Pro
  • Audio: everything sums into a Yamaha IMX644 line mixer
  • Controller: an Arturia MiniLab hanging off the Debian box

The Debian box reaches the MOTU through a Roland UM-1SX USB MIDI interface, and it also records the Amiga’s PAL composite output through one of those ubiquitous MacroSilicon USB capture sticks.

What the Debian box actually does

This is the interesting part — the boring, cheap Linux box turned out to be the most capable machine in the room:

  • Qtractor sequences the rack; Yoshimi plays the MiniLab locally.
  • amidi / aplaymidi drive raw SysEx: mode switches, identity probes, bank dumps. The port syntax gotcha is worth knowing: amidi wants raw devices (hw:4,0,0) while aplaymidi wants sequencer ports (32:0).
  • rtpmidid advertises the whole rig over RTP-MIDI/Bonjour so a Mac (or anything else on the network) can join the MIDI fabric.
  • ffmpeg records the Amiga at 720x576 PAL from the capture stick.

The SC-88 Pro as an MT-32

The SC-88 Pro has a hidden-in-plain-sight “System Mode Set” SysEx that re-maps the whole module to the MT-32’s sound set. Three bytes of payload and a Roland checksum:

F0 41 10 42 12 00 00 7F 00 02 7F F7

After that, the classic public-domain MT-32 game soundtracks (Space Quest 1, King’s Quest V, Leisure Suit Larry 1, Silpheed, Laura Bow 2, Conquests of the Longbow, Willy Beamish) play straight off the disk:

amidi -p hw:4,0,0 -s sysex/sc88pro-mt32-mode.syx
sleep 3
aplaymidi -p 32:0 media/kq5mt/kq5mt.mid

It is a partial emulation — custom timbre banks from .SYX files are approximated rather than loaded — but it is remarkably convincing.

Lessons from the MOTU Timepiece II

  • The factory default routes each input only to its same-numbered output, which makes a cross-patched rig look completely dead.
  • Routing is front-panel only. The reverse-engineered MTP AV SysEx routing commands found online do nothing on a plain Timepiece II.
  • The DATA DUMP window transmits the unit’s state to output cable 8 and the computer port only — fine for archiving, awkward for verification.

Status and next steps

The Debian ⇄ SC-88 Pro path is verified end to end, including SysEx round trips. The JV-2080 is not yet receiving MIDI (cabling under investigation), the Ultra Proteus is cabled but untested, and the Amiga and Atari are waiting on their MOTU ports. The full SysEx reference for the Ultra Proteus — including the plan for playing it like a knobby synth through its Midimap system — is in the project docs.

Everything is documented in the projects/retro-midi-studio/ directory of this site’s monorepo — wiring diagrams, per-device notes, the SysEx library and the soundtrack playback workflow.