title: Detect activity level of microphone in flex
body: <p>I have to detect avtivityLevel of microphone in Flex. I am using the activityLevel property of Microphone class but as I found out it always return -1 even if I have done Microphone.getMicrophone().
  To detect activity level we have to set microphone.setLoopback = true;</p>
  
  <p>Does anybody know how to do this without using loop back as I do not want to hear my sound back just monitor the activity level</p>
  
  <p>Thanks</p>