I have a new Toshiba HDTV and when scanning the channels from Comcast to pick up the digital subchannels (88-1, 92-11 etc) the audio disappeared after about 10 minutes and has not returned. I have the cable split, one side direct to TV and the other into a HD cable box. The direct to TV is where I did the scan. Is this Comcast's way of forcing you to get their box to get HD and other digital channels? I have the HD box so it's not a big deal but I was curious as to why the audio suddenly disappeared on the subchannels while the other regular channels are fine.