title: how to fix Ubuntu no audio for applications?
body: <p>Problem break down:</p>
  
  <p>both system speakers and a another set of speakers appear in sound GUI.</p>
  
  <p>both pass the test audio test.</p>
  
  <p>system sound is null until I adjust volume on keyboard then system audio will play when volume is adjusted with mouse.</p>
  
  <p>problem started after successfully playing a movie using HDMI to a tv. </p>
  
  <p>I have tried restarting ALSA and pulseaudio. </p>
  
  <p>Problem appears to fix itself randomly after a few days. </p>
  
  <p>There maybe a connection between the problem and switching audio output device as the problem came back once I performed a restart with headphones plugged in.</p>
  
  <p>Any Ideas ?</p>