Not specifically musical, but beautiful hacking nevertheless...
How to generate exactly the frequencies you want!
The file format of the step mod explained!
Cartidge Expansion spec, OS disassemblies, disk format, etc. Plus parameters and commands for the Ensoniq Mirage and Sysex implementation, and reverse-engineered schematics, etc.
More technical info than you can believe about these synthesizers.
All the technical info we can get on the Ensoniq ASR-X!!!
Technology Vulturing the MOTU MIDI Time Piece. An interesting page.
Modified, Enhanced Lexicon JamMan software!
Okay, not exactly hacking, but still extremely useful and hard-to-find info. Sysex and MIDI implementation for Korg Poly-800
Hacking the Peavey SP (Coming Soon!)