7 or 5 speakers

In response to Redwoodgarden, the only speakers I don't have are rear and the possible side ones. Decoder is a Lexicon DC1, main speakers Mirage M3si. Rear and side amps are Adcom GFA 535. Seating position is 16 feet from front wall, so about 12-13 feet from screen.

7.

With the stock decoding algorithms on 5.1 sources, you get a bit more immersion from the side + rear surrounds. THX-EX encoded source will put sounds arround, beside, and behind you. Your Lexicon will also enhance pans from the front to rear speakers. My upgrade from 5.1 to 7.1 with a Lexicon DC-1 was worthwhile.

As far as the sub:

Home theater bass requirements for reference level LFE playback are ludicrous. Few commercial sub-woofers will not reach 115dB @ 20Hz @ 10% distortion.

My HT room is approximately 13' x 19' x 9.5'. I originally had a 5.1 set up, and used two side speakers (tripoles) and no rears. I then expanded to a 7.1 set up by adding two (monpole) rear speakers. For me, the improvement in sourround envelopment with 7.1 was significant, so much so that I will never go back to 5.1.

I listen to everything in 7.1, independent of source. I use Logic 7 in a Lexicon MC-12 to generate 7.1 outputs from any source.

Recommend you search through AVS Forums for posts by Sanjay. He has articulated several times why a 5.1 set up (whether that means sides and no rears, or rears and no sides) cannot give the same surround envelopment as a 7.1 system.

Thanks
Bruce

Homer, it sounds like you are all set for 7.1 except for the surround speakers. You can get excellent surround speakers at a moderate price by concentrating on high quality midrange and tweeters. Don't worry about the bass; it's not that important for movie surround speakers. Forget Bose speakers; they don't have any detail.

I would still recommend a second sub and put both in corners. Most HT that I have seen have a loose boomy bass that turns me off cold. Placing the subs in corners make them produce sound that you feel in your chest.

Yep... I do believe 7.1 it is.... Thanks for the input.