monome

"freeze frame audio" / spectral processing via fft and jitter (now if i could only understand it better... :p)
http://www.mitpressjournals.org/doi/abs/10.1162/comj.2008.32.3.87

since you posted the NI tutorials, here's a collection of basic filter design stuff for reaktor:

http://www.nireaktor.com/tag/filter-design/

includes the basic biquad, some WDF stuff, a formant filter, zero delay feedback, oversampling, and iterative filters.

the zero delay feedback and iterative tutorials are based off of vadim zavalishin's work at the NI site. i've done my best to dumb the math down to a high school level.

for high quality oscillators, i cannot recommend this document enough:

http://courses.cs.washington.edu/courses/cse490s/11au/Readings/Digital_Sound_Generation_1.pdf

crazy crazy stuffs

Wow, that's amazing. I didn't know, there's so much more available for free! Whoooooo, that's a lot to read...
Thanks for sharing!

currently reading "designing audio effect plugins in c++

here is the site for the book http://www.willpirkle.com/ which includes rackAFX plugin development environment (vst or au).

set up for a windows environment, but can make au . maybe a place to test ideas.

list of dsp stuff here

https://docs.google.com/document/d/1EwGqmNTPpaDPKmubltbxDrCj_Ia96HVTA398ymDq0D8/edit?usp=sharing&pli=1

oh and this makes FT make a bit more sense

http://www.r-bloggers.com/the-fourier-transform-explained-in-one-sentence/

Some pseudo-random thoughts:

There are a couple books on digital filters, check out "Digital Filters" by RW Hamming. (Yes, *the* Hamming of Hamming Window, Hamming Code, etc.) It's a Dover book so it's pretty cheap (~$12 US), and then there's my favorite, "Digital Filters for Everyone" by Rusty Allred. If you have a Kindle and Prime, you can check it out like a library book too.

Other cool books include "Musical Applications of Microprocessors" by Hal Chamberlin, "Digital Signal Processing 101: Everything you need to know to get started" by Michael Parker, and "A Digital Signal Processing Primer: With Applications to Digital Audio and Computer Music" by Ken Steiglitz. If you want a little more "engineer-like" book, a lot of people at my day job recommend "Understanding Digital Signal Processing" by Richard G. Lyons. It's easier to start with than the Oppenheim and Schafer stuff...

I almost hate to mention this next one because of the price, but if you really want to get a good handle on the compsci side of DSP (what does "MAC" really mean?), check out "Digital Signal Processing: A Computer Science Perspective" by Jonathan Stein.

There's a fun book on making a synthesizer in software, called "Basic Synth" with a corresponding web site: http://basicsynth.com/

Check out the Princeton Soundlab too (home of ChucK, Sndtools and Tapestrea):
http://soundlab.cs.princeton.edu/

For other source code, did anyone mention Pure Data, Supercollider and Csound? What about Sonic Birth? Zynaddsubfx? And how about the Bristol synthesizer emulations on SourceForge?

Oh, and my favorite of all, Electronotes. Anything and everything you might want to know about analog synthesis and a lot of digital stuff too...

:D

Ooh, new favorite book: Musimathics Volume 2 by Gareth Loy. Includes a nice section on imaginary and complex numbers...

@Doug, thanks for the excellent tip. The bookstore only had volume 1, and I'm a third of the way through -- picking up volume 2 tomorrow.

Miller Puckette's Theory and Technique of Electronic Music

http://msp.ucsd.edu/techniques.htm

Also available as a book.

http://katjaas.nl/
this site might be interesting ('might' as it's way over my head... you'll know).
fft, complex numbers, etc.
pd and c programming.