I have degree in computer science but I owe a large part of what I understand about physics and electronics to my speaker building hobby. I highly recommend getting into the physics of sound. It’s actually pretty simple and will teach you how waves behave in general.
I don't think I'll be building speakers anytime soon though, but I'm still very much interested in the details of psychoacoustics and sound reproduction.
I'm very interested in the Arduino based pre amp. Do you have a page with your design that I can study? I was thinking about maybe integrating a Lightspeed Attenuator.
Most of all, I'd like the pre amp to automatically turn on the power amp (currently a Gainclone) when a signal starts coming in from the connected Airport Express.
Here's another arduino-based pre-amp. This one includes relay-based stepped attenuators and input selectors. The pcbs are all available as well as the schematics in case you just want to use it as a base for your own project.
http://www.cs.helsinki.fi/u/ljlukkar/labsub/
I’m currently working on a Arduino based pre amp that hosts a rest api for remote controlling: http://tinypic.com/r/15yvj2g/8 http://tinypic.com/r/11vmhld/8 http://tinypic.com/r/jrzfk5/8