Whatever the format required by your development environment, it will help you to be able to convert to and from the usual audio formats, such as a .wav format.  You may have to write a simple .C program or Matlab routine to do this, or you can use an off-the-shelf audio editor, which will also allow you to examine audio files. Programs for doing this are inexpensive and easy to find.  On the PC, candidates include Adobe Audition http://www.adobe.com/products/audition/.    One multi-platform shareware editor is Audacity http://audacity.sourceforge.net/; a Google search will turn up others.  Matlab, Labview, and similar programs can also be used for this purpose.  There are more sophisticated audio editing programs, such as Steinberg Cubase http://www.steinberg.net/983_1.html, but they are overkill for most debugging purposes.  With such an editor you want to be able to:

• read files from disk and write files to disk in a variety of formats (including the one required by your debugging environment)
• zoom in to the level of an individual sample
• modify an individual sample
• read out the value of an individual sample
• scale parts of the waveform
• view spectral plots
• cut, copy, and paste waveforms
• listen to sounds
• and finally, generate test waveforms.

At an early stage in the development process, set up a passthrough test.  The development system should be able to pass a signal unchanged from the input to the output.  One version of such a test involves sending a known signal, like a sine wave, to an A/D converter on a prototype development board, and examining the D/A output on an oscilloscope while listening to a speaker. 

Figure 1. With no audio processing in place, an audio device should pass a signal through undamaged.

Ideally another version of this test involves injecting a digital signal after any analog-to-digital converter, and recovering a digital signal before any digital-to-analog converter. 

Figure 2. Ideally a signal can be read from disk and injected into the development
system, then picked up from the development system and stored to disk.

Any processing modules get dropped between these test points