title: Play one instance of AVAudioPlayer in the background
body: <p>I have several instances of AVAudioPlayer in my app (in separate classes). I have added multi-tasking capabilities to one instance but all audio now plays in the background. I added the 'App plays audio' key to my plist and:</p>
  
  <pre><code>    [[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayback error:nil];
  [[AVAudioSession sharedInstance] setActive: YES error: nil];
  </code></pre>
  
  <p>to my class. How can I target this code to only 1 instance of AVAudioPlayer?</p>