Topic: [Apple II] Electric Duet
So if you've ever looked into Apple II matters, you've probably heard of Electric Duet. If not, check this vid for a little introduction. As you can see, just two tone channels with variable duty. Nothing special at all. Except that the program is from 1981, predating multichannel Spectrum beeper music by several years. It might actually be the first use of the "pulse interleaving" technique.
As I recently did a track using Electric Duet, I got curious and wanted to learn more. A friendly soul then pointed me to this place:
which contains a great write-up by the program's author, Paul Lutus, as well as the engine source code. A read I can certainly recommend!
On a side note, Electric Duet's GUI is surprisingly tracker-like. Especially so considering the "sheet music" type editors where all the hype back then, and real trackers didn't appear until many years later. Very fascinating.