UPDATED: These steps work with MacOS Catalina 10.15.2: 1. Download and compile midi_patchbay from here: https://github.com/notahat/midi_patchbay 2. Download and compile SIDPlayer 4.2, with TK's modified ASID code here: https://github.com/mselin/sidplay4-asidmod 3. If you're a N00B like me, you'll need to create a developer ID with Apple and substitute this for the DevID in the code, as well as the team name, in order for builds to work. This might be obvious for a real developer,