I just purchased a DP554441 Sanyo tv. I had surround sound on my Vizio last time, so I connected it the same on this TV. The sound plays through the speakers however I am unable to adjust the sound. The receiver just has a volume knob to turn it up and down. I know there is some setting that I am missing and cannot locate it in the Audio settings. Can someone help? Do i need to plug in the red/white plugs into my DVR box?