title: Trying to understand AVAudioPlayer and audio level metering
body: <p>I'm trying to understand AVAudioPlayer and audio level metering. What I have below is an object "AudioPlayer" that is playing a short audio sound. Now I want to output the power of this sound (decibels). Somehow I don't think I'm doing this right. </p>
  
  <pre><code>        audioPlayer.meteringEnabled = YES;
          [audioPlayer play];
          int channels = audioPlayer.numberOfChannels;
          [audioPlayer updateMeters];
          for (int i=0; i&lt;channels; i++) {
              //Log the peak and average power
              NSLog(@"%d %0.2f %0.2f", i, [audioPlayer peakPowerForChannel:0],[audioPlayer averagePowerForChannel:0]);
  </code></pre>
  
  <p>The NSLog output of this is
  0 -160.00 -160.00
  1 -160.00 -160.00</p>
  
  <p>Now according to Apple "A return value of 0 dB indicates full scale, or maximum power; a return value of -160 dB indicates minimum power" So does this mean this sound is at minimum power? I don't think this is true because the audio snippet is a fairly loud sound. I think I'm missing something here, any clarification would be appreciated.  </p>