Sound processing

[vanilla]

Hi there,
I am working on sound processing and I wanted to implement some of my ideas on rockbox and check does they work. What I am trying to do is filtering recorded sounds according to few new algorythms I am testing. Is there some part of source code in rockbox that I could use as a example?
Thanks in advance.

[saratoga]

What do you want to implement exactly?  For effects on things like decoded audio or live recorded audio, a plugin might be the best place to start:

http://git.rockbox.org/?p=rockbox.git;a=tree;f=apps/plugins

Take a look at the fft and oscilloscope plugins for example.