title: how to play background music while recording voice?
body: <p>friends</p>
  
  <p>Now I'm developing iPhone Recorder App.</p>
  
  <p>I can easily record my voice with sample code.</p>
  
  <p>I want to record background music with my voice.</p>
  
  <p>For example,When I click "Record" button,background music plays
  Then I sing a song.</p>
  
  <p>In this case,I should record background music  with my voice.</p>
  
  <p>But,If I did like that,I can't record anything.</p>
  
  <p>What's wrong?</p>
  
  <p>To do this,what should I do?</p>
  
  <p>Please help me..</p>
  
  <p>Thanks.</p>