Yeah, I agree with Steve and as I stated before, that separation is important, which is why I placed the speakers in his layout where I did.
That said, putting the surrounds in the rear corners puts them in the same plane as the rear overheads. That just won't work well. Nice idea though from a "where can I stash these speakers" perspective.
Keep in mind that any immersive setup still relies heavily on a solid base 5.1 or 7.1 setup. In a 5.1 setup, the surrounds are on the sides, not the rear, and while the seating area is pretty far to the back, you really don't want the surrounds in a 5.1 setup (which should be the base that you build off of, or a 7.1 if going that route) behind the listening area. Most 5.1 soundtracks are created to just go to the side of the listener, and not behind them. That is where 7.1 comes in. Sound mixers wanted to take the surround experience even further by giving sound behind the listener, without losing the long standing side surround sound.
In my diagram above, the side surrounds are actually in front of the standard Dolby spec as well, but this has been experimented with countless times over at AVS for years now - having side surrounds in front of the listening area when there are either rear surrounds (like in a 7.1 setup) or other speakers further back, like the overhead Atmos speakers, and people have raved about it. It also allows for greater separation between all of those speakers, filling in the audio "gaps" in the room more, and letting the receiver/processor handle the sound placement.
Again, my diagram edits were based off of using only native Atmos/DTS:X content or one of their upmixers.
None of it is ideal, but that is the space that we are working with, and it will still be a great experience.
I still stand by my "monopole only" stance (I went from four QS8s for surround duty to four on-wall M3s when moving to Atmos and love it), but like Steve indicated, he loves it with his QS8s and "to spec or not" you really will have a great sounding room with speakers filling those gaps, and I am certainly not going to fault someone for liking quadpole speakers (about as far away from spec as you can get, LOL) in an Atmos setup if they like it.
Your room isn't as great as a purpose built space for audio, but your room also serves multiple purposes, and will have a cozy feel to it even when not watching movies.
So now you have even more to think about. Steve brings some new thoughts for you to the table.
Lots to think of.
