There may be a solution that gets 99% to home base, depending on your inputs/outputs on the HDTV & Cable box. Which make and model do you have for both? Regarding Bob's comment, I don't believe HDCP comes into play here since you don't need to pass anything back from the HDTV from what I can tell.
That Sony is not ideal unfortunately since it lacks the inputs/outputs you require. What might work in my scenario below may be slightly complicated, but worth a try. Anyway, the silliest thing for me is seeing that it offers HDMI but does not play back any high definition content(?) If you are within the return period, I would consider swapping it for an Onkyo HTIB system with better support for what you are trying to accomplish. This would cost $250-350 ballpark. An example @ Amazon would be the Onkyo HT S3500.
This is how I propose you connect everything, short of knowing your exact cable box model & HDTV info. If you can adjust/assign the input/output settings on all devices correctly, it should work. The cable box may require you to manually enter which audio connection you are using. Here's a reference for you regarding your Xbox 360 and how it should be connected:
Xbox 360 (HDMI out) --> (HDMI in) HDTV
"" "" (S/PDIF out) --> (S/PDIF in) Sony DAV...
HD Cable box (Component video out-RGB)--> (Component video in) HDTV
"" "" (Digital coaxial out) --> (Digital coaxial in) Sony DAV...
Sony DAV (HDMI out) --> (HDMI in) HDTV
Let me know if you need any assistance once you get it connected.
Hi everybody, I just recently purchased a Sony DVD Home Theater System that includes the receiver, 1 center speaker, 2 front speakers, 2 rear speakers, and a subwoofer. The system is the Sony DAV HDZ278. It sounds very good in my 10 X 10 room, but I just have a problem getting Dolby Digital 5.1 Sound. The system itself is a DVD player with HDMI, Component, and RCA outputs, and it also has a digital optical input. I plugged the HDMI cable from my receiver to my tv, and I have a digital optical plugged from my receiver to my tv. The digital optical cable gives me sound for my Xbox 360, cable box, etc. However, when I play DVD's on the receiver I get dolby digital 5.1 sound, it even says so on the display. When I play anything else aside from the DVD player, it says Dolby Pro Logic II on the display of the receiver. So when I play my Xbox 360 or watch tv on my HD Cable box it only shows Dolby Pro Logic II sound. I have tried several games on the Xbox 360, so its not the game's fault. ANy suggestions from anyone on how to get Dolby Digital 5.1 Sound for everything I play?