CoreAudioで音楽を鳴らす

意外と簡単にできた。以下のようにAVAudioPlayerを使えばよい。mp3も再生できる。

        NSString* path = [[NSBundle mainBundle] pathForResource:@"sound" ofType:@"mp3"];
        NSURL* file = [NSURL URLWithString:path];
        self.audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:file error:nil];
        [self.audioPlayer prepareToPlay];
        [self.audioPlayer play];

参考：objective c - cocoa playing an mp3 - Stack Overflow