From this excellent article:
This article intends to be educational. It hopes to provide the reader with a basic knowledge of sound and sound processing. Of course music is one of our concerns but all in all, it is just some noise among other less pleasant sounds.
First the physical concepts of sound are presented together with the way the human ear interprets them. Next, signals will be looked at, i.e. what sound becomes when it is recorded especially with modern digital devices like samplers or computers.
Last, up to date compressions techniques like mp3 or Ogg vorbis will be presented.
The topics discussed in this paper should be understandable by a large audience. The author tried hard to use “normal terminology” and particularly terminology known to musicians. A few mathematical formulas pop up here and there within images, but do not matter here (phew! what a relief…).