title: system sound on iphone not playing
body: <p>I want to play a system sound but I don't hear anything:</p>
  
  <pre><code>- (void) play_system_sound
  {
      NSLog(@"Play system sound");
  
      SystemSoundID soundID;
      NSString *path = [[NSBundle bundleWithIdentifier:@"com.apple.UIKit"] pathForResource:@"Tock" ofType:@"aiff"];
      NSLog(@"path = %@", path );
      AudioServicesCreateSystemSoundID((__bridge CFURLRef)[NSURL fileURLWithPath:path], &amp;soundID);
      AudioServicesPlaySystemSound(soundID);
      AudioServicesDisposeSystemSoundID(soundID);
      NSLog(@"Play system sound DONE");
  }
  </code></pre>
  
  <p>I don't hear anything. What am I doing wrong?</p>