title: How to play sounds in locked mode on iPhone
body: <p>Everybody knows the standard procedure to keep your app alive, after the user pressed the lock button (silent sound).
  If I start a sound with AVAudioPlayer (before the iphone is locked), the sound plays till it's end (after locking). The app is still running. If I try to start another sound while the iPhone is locked, it will never get played. All the other things work as well but the sound doesn't.</p>
  
  <p>How can I play a sound while the iphone is locked?</p>