title: Detect blow in Mic and do something
body: <p>i found this <a href="http://www.mobileorchard.com/tutorial-detecting-when-a-user-blows-into-the-mic/" rel="noreferrer">tutorial</a> , and it's good , but doesn't work for me ! </p>
  
  <p>here is the code : </p>
  
  <pre><code>- (void)listenForBlow:(NSTimer *)timer {
      [recorder updateMeters];
  
      const double ALPHA = 0.05;
      double peakPowerForChannel = pow(10, (0.05 * [recorder peakPowerForChannel:0]));
      lowPassResults = ALPHA * peakPowerForChannel + (1.0 - ALPHA) * lowPassResults;
  
      if (lowPassResults &gt; 0.95)
          NSLog(@"Mic blow detected");
   //change the background color e.g !
  }
  </code></pre>
  
  <p>in the console show me the nslog reseult like this  (without any bowling !):</p>
  
  <pre><code>2010-04-11 23:32:27.935 MicBlow[2358:207] Mic blow detected
  2010-04-11 23:32:27.965 MicBlow[2358:207] Mic blow detected
  2010-04-11 23:32:27.995 MicBlow[2358:207] Mic blow detected
  2010-04-11 23:32:28.026 MicBlow[2358:207] Mic blow detected
  2010-04-11 23:32:28.055 MicBlow[2358:207] Mic blow detected
  2010-04-11 23:32:28.086 MicBlow[2358:207] Mic blow detected
  2010-04-11 23:32:28.115 MicBlow[2358:207] Mic blow detected
  2010-04-11 23:32:28.145 MicBlow[2358:207] Mic blow detected
  2010-04-11 23:32:28.175 MicBlow[2358:207] Mic blow detected
  2010-04-11 23:32:28.205 MicBlow[2358:207] Mic blow detected
  2010-04-11 23:32:28.236 MicBlow[2358:207] Mic blow detected
  </code></pre>
  
  <p>i change this value : </p>
  
  <pre><code> if (lowPassResults &lt; 0.95)
  </code></pre>
  
  <p>to </p>
  
  <pre><code>if (lowPassResults &gt; 0.95)
  </code></pre>
  
  <p>so it seems work ! but doesn't chage anything , again if i put the background changing code the , my code change background but without any bowling !! 
  what's the problem ?</p>