AVAudioPlayer gives no sound output

I have imported audio toolbox and avfoundation to my class and added the frameworks to my project and am using this code to play a sound:

- (void)playSound:(NSString *)name withExtension:(NSString *)extension
{
    NSURL* soundUrl = [NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:name ofType:extension]]; 
    AVAudioPlayer *audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:soundUrl error:nil];
    audioPlayer.delegate = self;
    audioPlayer.volume = 1.0;
    [audioPlayer play];
}

I call it like this:

[self playSound:@"wrong" withExtension:@"wav"];

However I get zero sound.