title: Simple way change pitch with AVAudioPlayer?
body: <p>I want to use AVAudioRecorder to record a sound, and AVAudioPlayer to play it back, at a different pitch.</p>
  
  <p>I've tried changing the rate property of the audio player, which plays the sound faster or slower, but doesn't change the pitch.  Is there another way to accomplish this?  Can I, for example, record at 22kHz and playback at 44kHz?  I tried changing the player's audio settings but they're read-only.  Am I missing something simple? </p>
  
  <p>I've looked at different sound libraries, but I would just like a simple hack if there is one.</p>
  
  <p>Thanks!</p>