Might I suggest adding something to your project description that acknowledges this. I didn't see any mention of ADTPro or David Schmidt on the linked page or the github repository.
David Schmidt has contributed a lot of free software to the Apple II community over the years and, IMHO, deserves recognition for his work by those that build upon it.
The C code that encodes the audio is listed in the dependencies section [1], and ADTPro is freely acknowledged there. However, I'm more than happy to add some reference to the post because I think you're right.
EDIT: Aaaaaand acknowledgement pushed into post. Cheers.
Thanks very much for the acknowledgement. Your project looks like a lot of fun - very cool use of audio. And of course Lisp rocks. Another audio-based project is the Apple Disk Server - loading games directly to the Apple via cassette port:
http://asciiexpress.net/diskserver/readme.html
David Schmidt has contributed a lot of free software to the Apple II community over the years and, IMHO, deserves recognition for his work by those that build upon it.