For the last month or so I have been getting erratic volume fluctuations on my Sony XBR 1 TV connected to cablevision through a SA 4200HD box. Most HD stations (700 series channels) have very low volume even when TV volume is set to max. There is volume increase when a commercial comes on and it goes low again for the program. I have the TV also hooked up directly to incomming cable(without the box) and the TV has massive volume. Whe played through the box, The other channels (2-13 and the 300series) has volume that varies from low to normal depending on the channel and whether it is a program or commercial. Called cablevision and they checked that audio setting was "narrow". Is my problem the box or the TV? How can I check?