I have a brand new LG 50 plasma and a Bravia Sony surround sound system as well as a Cox Cable HD DVR box. I currently have it connected as such: HDMI from Bravia Sony System direct into TV HDMI from Cable box to TV Opitical cable from Cable box to TV I get wonderful surround sound when I play a DVD but there is absolutely no sound when I just want to watch TV. What am I doing wrong?

You may have to set the input value on the bravia for optical on the input from the cable box. sometimes there is more than one way for a particular input to receive an audio signal, you may have rca(red and white), a black or orange rca type for digital, and then the optical. i would suspect you have to tell the bravia how the sound is inputed into the bravia. also , just a thought.... on the cable box there should be a volume control on the front of the box........ make sure the cable box volume is ALL the way up (it is the preamp volume).