The Amiga has four hardware audio channels - two of the channels produce
audio output from the left audio connector, and two from the right.  These
channels can be used in many ways. You can combine a right and a left
channel for stereo sound, use a single channel, or play a different sound
through each of the channels to create four-part harmony.

 About Amiga Audio 
 Audio Device Commands and Functions 
 Device Interface 
 A Simple Audio Example 
 Audio Allocation and Arbitration 
 Allocation and Arbitration Commands 
 Hardware Control Commands 
 Double Buffered Sound Example 
 Additional Information on the Audio Device