I was also wondering what that knob was used for. The same glue that got my *** stuck to my chair, by accident got on that knob. I can hear music and movies just fine, I just can't hear a word my wife is saying. The last thing that I thought she said was "Get your butt up, and turn that down!" But who would ask such a stupid question, so I blew her off. I am still here in my chair with the music cranked up, I am not sure where my wife is? Mabey if I could of heard anything she said, I would..................OH who cares!! Turn it up, and get me a beer!!!!