What is the ideal distance off a back wall for the M80?
How about the LFR?
I'm pretty sure my equipment will stay upfront and center and I ideally I'd have 3' behind the cabinet.
This leaves a less than ideal distance between the back wall and rear surround channels.

It depends on the rest of the room.

7.5' vaulted x 14 x 19 with a 5' deep x 30" wide closet centered behind the sweet spot.
2 x 7.1 with 2 subs.
Or

9' flat ceiling x 16 x 21 no damn closet.

Mc Gruber....

... the final frontier ...
::que music::

In other words its almost impossible to plan a room around speaker placement.

In other words, that's the wrong approach unless you're an acoustical engineer with a large budget and the right software. Remember it's not just room size to consider, it's furniture, materials, wall treatments, etc.

I would say that 99.9% of people with home theatres, even dedicated ones, work with what they have. If they're good at it, they tweak it as they go along, moving speakers until it sounds good.

That said, with the right speakers and only a bit of tweaking, it still sounds pretty damn good, eh? Call that 80% (I've been watching a lot of Star Trek, where they quantify unquantifiable things with percentages). Hell, even in my living room, which is an actual living room with people and things moving around in it all the time and extremely non-optimal placement of the center, it sounds pretty damn good (65.2%, Captain!)

"Damn it Jim. I'm a doctor not an acoustical engineer..... with a large budget..... and the right software."

Without delving into the technical that I can't speak to because I don't play either of the above on TV...

Step 1. Sart with the M80s about 2 to 4 inches from the back wall so the rear ports have some room for rear 'portification.' Some tonality, mostly in the bass area, will change slightly as they get closer/further from the wall. There are no rules, just experimentation.

Step 2. Play with a little bit of toe-in until things sound nice wherever you sit. Ignore where everybody else sits or you will start down a long road of never ending adjustment. Enjoy!!!

Step 3. Start worrying about what others hear or otherwise decide to move something and stumble down the never ending, icy road of adjustment. Wave to the rest of us.

Step 4. Remember that your receiver does automatic EQ analysis. Run that and be happy again.

Step 5. Wonder if you moved your speakers slightly and re-ran the auto-setup on your receiver, would it sound better? Do that. Find yourself back on the endless road. Wave to Brian who is driving home with his 23rd speaker for his "wall of sound".

I must admit, it does sound very good now. Is it perfect? No, always room for improvement, but I think I've squeezed out about all I'm going to get from this arrangement, so I'm finally satisfied. Except for a future subwoofer upgrade.

Ever wonder how much better it could/would sound with M60/M80s to go with that VP160?

That was the delima. There was no room for these.

It's just you and your cats there must be room, you can always walk around the speaker to get to the hall etc.

Nope. No room. They'd have to be under the Tv and raise the TV, which I don't want to do, stick out too far and be too close together. In some other place maybe, but not here. The sound as is still amazes me. Multiple M22's together sound much better than just a pair. And the single Vp160 adds depth, with the Ep350 adding bass. It's all good.

Old thread renewal...
With Atmos here Brian is ahead of all of us speaker wise.
Rereading some old posts. Can't believe some of the crap I made you read. Lol.