Installed PAX on iMac running OS X 10.8.4. Started World of Warcraft in evening and was unable to hear any audio. Tried to correct, but unable to fix. Finally, uninstalled PAX using CleanApp and audio returned. Was seeing message in system logs at WoW startup from coreaudio saying audio inactive. Those messages did not occur once PAX removed.
My WoW audio works fine over Parallels Access. Playback: all options checked except "Sound in Background", "Enable Reverb", "Headphone Mode" (but those work if they are checked anyway) Sound Quality: High Game sound Output: System Default (or you can try explicitly setting this to "Parallels Virtual Audio Adapter"). Sound Channels: High (64) Use Hardware: checked Volume: 100%