The problem is that when compiling with ARC you need to make sure to keep a reference to instances that you want to keep alive as the compiler will automatically fix "unbalanced"
alloc by inserting
release calls (at least conceptually, read Mikes Ash blog post for more details). You can solve this by assigning the instance to a property or a instance variable.
In Phlibbo case the code will be transformed into:
NSString* recorderFilePath = [NSString stringWithFormat:@"%@/MySound.mp3", [NSHomeDirectory() stringByAppendingPathComponent:@"Documents"]];
AVAudioPlayer *audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:[NSURL fileURLWithPath:recorderFilePath] error:nil];
audioPlayer.numberOfLoops = 1;
[audioPlayer release]; // inserted by ARC
AVAudioPlayer it will stop playing immediately as it gets deallocated when no reference is left.
I haven't used ARC myself and have just read about it briefly. Please comment on my answer if you know more about this and I will update it with more information.
More ARC information:
Transitioning to ARC Release Notes
LLVM Automatic Reference Counting