I've been trying to setup a modest surround sound setup based on the above tv but am unable to tell whether the built-in sub-woofer is working or not. Using the audio test on the 'Reign of Fire' DVD THX setup I get a test tone from all the speakers except the sub-woofer. The sound levels of the speakers have a slide control (on screen) but the sub-woofer only has a Low/Normal/Full setting. So I don't know if the sub-woofer is working, very quiet, switched off somewhere or what. Anyone have this tv and sussed it? I have sub-woofers on my PC's and the my previous tv/dvd used an old 5.1 Dolby (Cambridge Soundworks) setup so I'm sort of expecting a bit more oooomph.