Sony surround sound hookup
In short, the answer is: Hook up all three to each other. I have a Samsung DLP HDTV, and I was trying to hook up a Sony DAV-HDX500 home-theater system and a Comcast HD set-top box, but I found that the Sony user guide is helpful only for setting up the speakers. Most of what it had to say about HDMI and getting the TV sound or cable sound to go through the speaker system was wrong (or, at least, it didn't work for me). So, here's what I did. I connected Component video cables (Y/Pb/Pr out) from the Cable box to the TV (Y/Pb/Pr in), audio cables from the Cable box (audio out) to the Sony system ("SAT/Cable" audio in), and an HDMI cable from the Sony system (HDMI out) to the TV (HDMI in). This allows me to 1) watch DVDs with surround sound through the TV's HDMI source (when the "DVD" format is selected on the Sony system), 2) watch cable with surround sound through the TV's Component source (when the "SAT/Cable" format is selected on the Sony system), and 3) watch cable WITHOUT the surround sound, as I did before I ever had the Sony system. One item of note: When watching a non-HD channel with the surrond sound on, the audio is slightly out of synch with the video; thankfully, there's no such problem on HD channels. Anyway, I hope this helps. It drove me crazy for two days straight!