Collaborate with other modders to make Synthesia the way you want it.
Always the latest versions: [ colors.xml | ui.xml ]
Read the Getting Started topic to learn how important it is to MERGE YOUR CHANGES every time you download a new dev preview.
Mac has a MIDI "loop back" driver built in: the IAC Driver. That should be able to solve the problem the same way that Gregor showed on the Windows side.