I AM LOOKING AT ZENITH ZHX-313 HOME THEATER AND WANT TO USE IT WITH
HDTV. ZENITH HAS ONLY (1) COMPOSITE VIDEO/AUDIO CONNECTION. WILL THAT
PROCESS DOLBY 5.1 FROM THE TV? OR WILL IT JUST BE PLAIN STEREO?

Howdy grego495-ga,

From the specification sheet for the ZHX-313 from the Zenith website, we can
see that the home theater system in question has, among other capabilities,
Dolby Digital 5.1 channel decoding.
http://www.zenith.com/sub_prod/downloads_pdf/ZHX-313.pdf

As you, quite correctly point out, the system has a composite left and right
audio inputs.  The ZHX-313 will take a Dolby 5.1 signal from that input and
process it just fine.

This all depends on the source of your input carrying a Dolby 5.1 signal, so
the real question actually is whether your television source carries a Dolby
5.1 signal.  If it is cable or one of the "little dishes," then chances are
your source does carry a 5.1 signal.

Even though it is on the increase, a large percentage of media just doesn't
have Dolby 5.1 audio as well, so don't be surprised if the Dolby Prologic II
and DTS capabilities of the ZHX-313 come into play.  These are other ways
that all of the speakers get used.

Since you mention using this system within an HDTV environment, I would
suggest you increase your budget and get a system that has at least component
and digital inputs.  As you know, the ZHX-313 has neither, so I don't think
you will be satisfied with the ZHX-313 in a HDTV situation.

Here are some other systems to consider.

Yamaha YHT-270
http://esupport.sony.com/US/perl/model-documents.pl?mdl=HTDDW900&region_id=1
http://www.yamaha.com/yec/products/productdetail.html?CNTID=200509&CTID=5000800&ATRID=1000&DETYP=ATTRIBUTE

Sony HT-DDW900
http://www.jr.com/JRProductPage.process?Product_Id=4109401&JRSource=googlebase.datafeed.SON+HTDDW900

Please note that the Sony has HDMI input/outputs, which is even better for
HDTV systems.

You will notice that neither of the above have VHS or DVD capabilities, as
I would recommend you get a separate box for that.

If you need any clarification, please feel free to ask.


Search strategy:

Google search on: home theater in a box HDTV
://www.google.com/search?q=home+theater+in+a+box+HDTV

Google search on: home theater in a box HDMI
://www.google.com/search?q=home+theater+in+a+box+HDMI

Personal experience of having upgraded my own sound and video systems several
times over the past 12 years.

Looking Forward, denco-ga - Google Answers Researcher