7.1 reciever w/ 5.1 speaker set-up

I rambled on a bit, so I have placed the main question in bold text...

Alright, I really want to get the Sony STR-DG820 for these reasons:

1. HDMI: It's 1080p compliant (as is my LCD and Blu-ray player). There are two cheaper model receivers (STR-DG520 & STR-DG720), but they do not appear to be 1080p.

2. It supports Dolby TrueHD Decoding & DTS-HD Decoding...along with others...

3. My wife said I could have it!

Now, I have one issue and one issue only. I cannot add two more speakers to the back of the room. A 7.1 speaker set-up is not an option due to furniture placement and wife issues with too many speakers.

I am under the impression that the two additional rear speakers in a 7.1 set-up...actually spit out the same audio as the only two rear speakers in a 5.1 set-up. Basically, that in a 7.1 set-up...all four rear speakers output the same exact audio. Is this correct? If so...I will be a very happy man because I can get this receiver and my speaker set-up won't give me issues. I don't mind only have the two rear speakers and maybe I can add them in later.

The only thing that I will have that will not work with this reciever is my sub I guess. The one I have now is not powered. It just has speaker wire running out the back that I put into the spring loaded contraptions for L & R on the back of my current receiver. It looks like the STR-DG820 just has some kind of line out for the sub. I'm assuming this is standard for powered subs. I'll just have to find one that won't make my wife freak out.

Thank for any help you can provide.

Thanks for the help...

Oh, and about the sub. I remembered that I have another one which is actually powered. It was given to me after only being used for a few months. I never had any need for it until now. It is a JBL SUB160:

It has eight connections for speaker wire (4 out & 4 in). These are labeled as "High Level".
It has a section of connections labeled "Line Level In". They are LFE, and then a red & white connection labeled L & R.
It has a Auto/On switch
A subwoofer level dial
A power switch
and finally a power cord labeled as AC 120 V-60Hz, 250 Watts.

My first guess would be that the Audio Out for sub woofer section on the back of the STR-DG820 would lead to the LFE Line Level In on the sub itself....yes?

It looks like this sub might have been part of a speaker package...I'm trying to figure out which one so I can get the manual for hookup info.

Edit: I found a manual for two similar subs. The connections are identical on the back. The manual explains that I need to connect the LFE output connection on the back to the sub itself to the LFE input connection on the receiver. This sounds fine, but I do not have an "LFE" on the receiver. Is the LFE connection on the Sony STR-DG820 actually "Audio Out Sub Woofer?





If so...that would solve all my issues.

Also, what type of cable would be used to connect the two?

Thank you very much! You've been very helpful and answered all of my questions. I think I'm good to go now.