All the commands that you can give to the audio device should be sent by
calling the beginio() function.  this differs from other amiga devices
which generally use sendio() or doio().  you should not use sendio() or
DoIO() with the audio device because these functions clear some special
flags used by the audio device; this might cause audio to work incorrectly
under certain circumstances.  To be safe, you should always use BeginIO()
with the audio device.