What are the speaker placements for 7.1 HT setup?

Go to Dolby's web site, and they explain the various set-ups for 5.1, 6.1, 7.1, and PLII.
www.dolby.com

Kee_tan,

7.1 will provide a more enveloping surround environment than 5.1. I personally found it significantly better.

A 6.1 speaker array is not a good choice. A single rear speaker is subject to front-to-back reversals and doesn't spread the rear surround information across the rear of the room.

For 7.1, the Dolby web site should show side speakers at plus & minus 90 degrees; i.e., side speakers directly to the side of the listening area (not behind and not in front). Rear speakers should be plus & minus 150 degrees. You may want to experiment with side speaker location if there are multiple rows of seating.

The size of the room per se is not an issue for 7.1, but layout within the room can be. My room is only 13' x 17' x 9.5', but my listening position is such that my rear speakers are behind me. There can be situations when 7.1 is not easy to implement; e.g., if your seating is flush against the back wall and cannot be moved forward to provide some space behind.

Unfortunately, the MX-134 only has DPLII, not DPLIIx, according to the McIntosh web site. You should have DPLIIx or Logic7 to take full advantage of a 7.1 speaker layout. Can you get an MX-135 instead of the MX-134?

Thanks
Bruce

Bruceomega,
My apology, some of your acronyms have eluded my
understanding. I must confess I'm a complete beginner
in HT. What is DLPII and DLPIIx? Are the differences
significant enough to yield my purchase of the MX-134
a plunder? Could be my interpretation, but I'm reading
the matter as MX-134 can only deliver pseudo 7.1?

You'll do well enough with just Dolby Prologic II, go into dolby's web site and if you have any doubt come back here.

..."Go to Dolby's web site, and they explain the various set-ups for 5.1, 6.1, 7.1, and PLII.
www.dolby.com"
Teonyc

This is not bad starting advice, as a good point of reference and suggestions. However, to be true, each setup/room is different, and there's A LOT OF VARIABLES TO CONSIDER! If you don't know what you're doing, you'll be getting hodge-podge sound from all your speakers. Placment is a balance of getting a properly scaled soundtage perspective, and simultaneously getting basically "flat frequency response"(and even response) from all the speakers! Anything else will give you lackluster performance for certain!(what everyone ends up with doing it themes, themselves sadly..I know Basically, as I've been doing this for years for a living)
All the other variables will then need to be considered, like proper toe-in, "aim", and acoustics considerations.
Basically, you're better off(especially since you spent all that money on gear) haveing someone consult you for best. Otherwise, spend years learning and studying, tinkering and tweaking. Bottom line, much more info is needed to recommend for ANY ROOM/SETUP!
Telling someone to stick your speakers at such and such a distance or location in your room is all relative. Also, each speaker is different, and reacts differently in the room. It all must be considered, as the room/setup/acoustics/tweeking/etc, all add up to easily 2/3's of the performance...no joke!
You spent hard on the gear...I suggest considering spending even wiser on the more critical setup/acoustics proceduress if you want anything remotely resembling world class sound!
Yes, equip makers would love you to think that simply buying gear is the answer to world class sound...seasoned audio experts know different. And you'd be amazed at how many (guy's especially) people think they can buy some fancy gear, stick it in a room, and think they have the best sound!...they're wrong....most end up with poor sound, I garantee it, sadly.
As for your gear choices, your gear is fine. You could alwasy tinker with power sources and wires and such. But otherwise that's good stuff. However, like most, the speakers really should be chosen first, as they're the most important in the gear. You then should match gear to match! That's correct normally. But, it's all workable if need be. Good luck