From the ALSA wiki

Advanced Linux Sound Architecture

This is an unofficial Wiki about the freely available ALSA sound architecture which provides low level Audio and MIDI functionality to the Linux operating system. Read the introduction and about page for more information about this site and visit the official ALSA Project site for additional information.

Driver Matrix

An alphabetically sorted list of all available drivers.

Installation

Issues dealing with installing and setting up ALSA for the first time.

Usage

Operational usage notes for ALSA, tools, utilities and applications.

Advanced

How to compile ALSA from source code and documentation for developers.

Troubleshooting

Help when dealing with ALSA problems.

Miscellaneous

Links to offsite documentation and specialized Linux distributions.