This chapter shows you how to directly access the audio hardware to
produce sounds. The major topics in this chapter are:

   *  A brief overview of how a computer produces sound.

   *  How to produce simple steady and changing sounds and more
      complex ones.

   *  How to use the audio channels for special effects, wiring them
      for stereo sound if desired, or using one channel to modulate
      another.

   *  How to produce quality sound within the system limitations.

A section at the end of the chapter gives you values to use for creating
musical notes on the equal-tempered musical scale.

This chapter is not a tutorial on computer sound synthesis; a thorough
description of creating sound on a computer would require a far longer
document.  The purpose here is to point the way and show you how to use
the Amiga's features. Computer sound production is fun but complex, and it
usually requires a great deal of trial and error on the part of the
user -- you use the instructions to create some sound and play it back,
readjust the parameters and play it again, and so on.

The following works are recommended for more information on
creating music with computers:

   *  Wayne A. Bateman, Introduction to Computer Music
      (New York: John Wiley and Sons, 1980).

   *  Hal Chamberlain, Musical Applications of Microprocessors
      (Rochelle Park, New Jersey:  Hayden, 1980).

 Introducing Sound Generation      Using Direct (Non-DMA) Audio Output 
 Forming and Playing a Sound       The Equal-tempered Musical Scale 
 Producing Complex Sounds          Decibel Values for Volume Ranges 
 Producing High-quality Sound      The Audio State Machine