title: is it possible to change the playback pitch of an audioqueue
body: <p>This is supposed to be possible on Mac OS X by overwriting the sample rate in the AudioStreamBasicDescription then create a new output queue.</p>
  
  <p>I've been able to retrieve the default sample rate and write a new one (ie. replace 44100 with 48000) but this is not resulting in any pitch change in the output signal.</p>
  
  <pre><code>err = AudioFileGetProperty(mAudioFile, kAudioFilePropertyDataFormat, &amp;size, &amp;mDataFormat);
          if (err != noErr)
              NSLog(@"Couldn't determine the audio file format");
          Float64 mySampleRate = mDataFormat.mSampleRate; //the initial rate
          if (inRate != 1) {
  //write a new value
              mDataFormat.mSampleRate = inRate;
              //then 
  err = AudioQueueNewOutput etc.
  </code></pre>
  
  <p>Any suggestions would be greatly appreciated. </p>