Comments for sound chapter

The chapter seems great so far.  I haven't touched sound in oF before, but I was able to follow your chapter just fine. 

As far as covering openFrameworks vs covering DSP stuff, I think the balance you are striking seems solid.  There could maybe be a tiny bit more that peeks behind the scenes of openFrameworks to give the reader a sense of how oF interacts with the speakers/mic/sound card.  Those types of things aren't in the current oF documentation.  Also, any place where you felt like geeking out more about DSP or other advanced topics, I would throw in a link to other resources to check out (and maybe a short footnote).  That would turn your chapter more directly into a jumping off point for exploring sound processing and synthesis in oF.

I'm curious to see what the sound synthesis section shapes up to be.  Much of the chapter felt conceptual, but this section would be the part that would make me open up a new project and start playing around.