Originally Posted by Manchild
You are correct insofar as that if the mixers themselves had a better setup (e.g. 11.2) they would have a greater palette to create their experience if you will. However, we know they don't today (by and large) and as such we as consumers (and more directly the equipment manufacturers) utilizing this equipment are basically saying "well we know how you'd want it to sound if you had these cool stuff". Maybe that's accurate, maybe it isn't...who knows; but what I do know is that if I play it in the original source format (properly EQed and the like of course) it should be almost exactly what the mixer heard and said "that's what I want my movie/show to sound like".
I guess my point was that there's a (theoretical) difference between reproducing their intent and reproducing what they heard in their mixing room
Which of those each of us prefer to reproduce in our own setup is, as you mentioned, our own choice of course.
On a bit of a tangent - I seem to remember a discussion around here from a few years ago(?) about how movie theaters typically can't produce low bass (below 35Hz or something like that), purely because of physical limitations (needing to fill a movie theater with authoritative bass below 35Hz would simply take too much power for the average theater.) I seem to also remember (i could be wrong of course) some people in the know to comment that a good number of mixing stages cannot really go down to the low numbers that are routinely thrown around here when discussing subwoofer performance in our own setups. So some of the people here have a more capable subwoofer setup than some mixing stages and theaters. Does that mean that those setups are not accurate or desirable?
From a purist point of view, if you take it to the extreme, you'd really want to have speakers and subwoofers with the same characteristics as those of the mixing stage used for the particular movie you're watching. That becomes largely impractical of course!
As to the accuracy of 6.1/7.1 vs 5.1, i look at it this way:
In my setup i have 3 identical speakers across the front. When i sit in the sweet spot, i cannot tell a difference between when i turn my center channel on or off (in my AVR of course, so that it can properly reroute the center channel info to the FL & FR speakers.) It has happened more than once when i was tweaking my setup that i encountered the situation where i thought my center channel was on and it turned out it wasn't! When sitting in the sweet spot, sounds that are supposed to be centered seem to come from the center of the image whether my CC is enabled or not. But as soon as i move to a seat that's to the side of the sweet spot, things change: Without the center channel, sounds that are supposed to be anchored to the center now shift left or right relative to the image, depending on where i sit. With the center channel enabled the sounds stay anchored to the center of the screen. I think we would all agree that the center channel helps to create a more accurate reproduction of the intent of the mix in that case.
I see the extra surround rear channels in the same way. If you have just 1 listening position that's in the perfect spot, you should not need the rear channels to image sounds in the rear center; the SL & SR speakers should be able to do that just like the FL & FR speakers are able to do it without the front center speaker. However, once you move to a seat to the side of the sweet spot, you have the same problem described earlier for the front stage without a center channel speaker. With the extra rear speaker(s), the sounds that are supposed to be somewhere in the rear are placed closer to the correct spot regardless of seating position. So depending on your situation, more speakers may enable you to more accurately reproduce the intent and what the mixer heard.
As we all know, this hobby is an exercise of making acceptable compromises