Not only did Opcode produce excellent MIDI software for the Macintosh but they also made the some of the best MIDI interfaces for the Mac to ever exist. It all started with the Opcode MIDIMAC back in 1986 and went on from there.
Atari had the MIDI power in the 80s, but it was definitely the Mac's territory in the 1990s. I still miss it.
All the Opcode Studio manuals listed below are in PDF format. I am still searching for a PDF version of the Opcode Studio 3 user manual. If you have access to this file, please contact me.
All the OMS manuals listed below are in PDF format.
The Opcode Galaxy manual listed below is in PDF format.
All the Vision and Studio Vision manuals listed below are in PDF format.
The AudioMedia and AudioMedia II cards from Digidesign were hardware audio recording and playback cards for the Macintosh II platform. The were NuBus cards (96 pin Texas Instrument design) and were therefore limited to Macs with available NuBus slots.
Opcode's greatest contribution to the MIDI world was probably the Opcode MIDI System, a.k.a OMS (which was later renamed the Open Music System). OMS was a set of system software for the classic MacOS that managed MIDI routing and processing.
Opcode made MIDI and later audio software for the Macintosh platform in the late 80's and the 90's. Eventually they did release their MIDI sequencing app Vision for Windows as well, but their primary focus was always the Mac.