How do i play multiple audio files simultaneously using AudioQueue?

Question

I've basically gutted what I don't need from the "Speakhere" sample app and I'm left with something I can use to play audio files. I converted wav files to aiff and then renamed the aiff to caf (Just in case this matters). I even tried shortening the files to 10 seconds long, but no difference. I am able to play files singly, but am unable to play more than one file at the same time. When I try to play multiple files, the first one plays correctly but the second will play a horrible long beeping sound. Sounds almost like a buzzer and sometimes will sound like a high pitched beep. My code has all the audio components like the speakhere app (AudioQueueObject, AudioPlayer, AudioViewController). I've changed the AudioViewController to be just my "AudioController" class where when I initialize, I pass in the name of the file and it replaces this line of code:
CFStringRef fileString = (CFStringRef) [NSString stringWithFormat: @"%@/Recording.caf", self.recordingDirectory];
with this:
CFStringRef fileString = (CFStringRef) [NSString stringWithFormat: fileName, self.recordingDirectory];
Any suggestions? I've been yanking my hair out trying to figure this out and I simply can't. I'm about ready to pull an "Office Space" but instead of beating up a printer, I'm going to destroy my macbook.
*NOTE: I have only tried this in the simulator, but I'm assuming it will do this on the real thing so I haven't bothered to try.

Answer 1

Unless I'm mistaken, you need one AudioQueue object for each audio file you want to play. In one of my apps, I basically copied the code provided in the [AudioQueue programming guide|http://developer.apple.com/iphone/library/documentation/MusicAudio/Concep tual/AudioQueueProgrammingGuide/AQPlayback/chapter4_section_1.html#//appleref/doc/uid/TP40005343-CH3-SW1] and made a wrapper object for playback. So then you can do something like this:
MyAudioManager *manager1 = [[MyAudioManager alloc] initWithFile:@"file1.caf"];
[manager1 play];
MyAudioManager *manager2 = [[MyAudioManager alloc] initWithFile:@"file2.caf"];
[manager2 play];
// etc...
If you want to play short files (~10s or less), you can use the simpler AudioServices functions along with SystemSoundID's. It will work fine if you have playback from AudioQueue and AudioServices at the same time.