Hi

The following is not based in science. Just gleamed from my years of experience with TV’s dating back to when a 27 inch CRT TV was home theater size.

Nice looking space BTW!

The average seating for and average adult (5.5ft  to 6 Ft - male/female) places the viewer at approximately 36 inch eye level above the floor. Smallest TV size today for home theater should be 55 inches. So my suggestion is 36 inches above floor level and maybe an inch more for each 10 inches of TV size. Therefore your recommended height from floor would be 38 inches. That’s room enough to mount a sound bar below.

Viewing distance from the screen should be where one does not have to tilt their head up (or down) nor move their eyes side to side to view the entire screen.

The only possible issue I see in your diagram is the dark chair to the left which may interfere with other viewers. Of course the person seated there will probably have a difficult viewing Angle.  

Others I’m sure will have their opinions to offer 

Note: I have a 65 inch LG OLED mounted 37 inches above floor with Arc setting on a equipment cabinet 2 inches below the TV. Viewing distance is 9 ft from TV.

One other thing to consider is if you want people standing in the kitchen to be able to see the full TV image while people are sitting on the coach.  No heads in the way.  I suspect 36-38 inches won’t be an issue, but you might want to measure it out just to be sure.  You could mark a line on the wall where you think the bottom of the TV is, having the tallest family member sit on the couch, and then see if a typical adult can see the line you drew from the kitchen.

https://www.avsforum.com/threads/how-high-to-mount-samsung-75%E2%80%9D-frame-tv-with-sonos-arc.3216870/

I disagree with the 50 inch suggestion on AVS.  Yes those standing in the kitchen will be looking down slightly, but at that distance, it’s a pretty small angle, smaller than the angle from couch to wall.  Plus, looking downward is a bit less effort than upward.

Also, you are likely going to have a lot of glare on the TV from the windows, more so than the TV mounted above the fireplace.  I’d be looking at blinds/shades/shutters/draps for those windows.

Thank you for all the replies. The TV is about 38” tall so if it was mounted at 50” center line it would put the bottom at 31” from the ground and 19” above the trim. I don’t think I would want it any lower because if the sound sound bar is added it would only be 10” or so off the trim. 
 

@AjTrek1 Were you thinking the bottom of the tv should be 38” from the floor?

@groundedchevy 

Yes, sorry I didn’t make that better understood. You might check out the Arc mounting options at the link 
Below.

https://www.sonos.com/en-us/shop/accessories/speaker-mounts

Sonos also recommends a minimum distance of 4 inches between the bottom of the TV and the top of the Arc (when Arc is wall mounted). Using my suggestion of 38 inches between the bottom of your TV and floor with a distance of 4 inches between the TV and the Arc places the bottom of the Arc at 30 inches above floor level. Coincidentally, the Arc would be at relatively the same distance above floor level if it were placed on top of an entertainment cabinet ( average height of 29 inches).

I wanted to thank everyone for the help. I took @AjTrek1 advice and mounted the bottom of the TV at 38”. Im overall really happy with it in the space. We hosted football and it didn’t matter if you were sitting or standing everyone had a good view. If this was a sit down only room the tv would be too high for me. My favorite viewing level is my eyes to be in the middle of the screen. In this room it would have looked off balance and weird. I’ll post pictures once I move the electrical behind the wall and the house gets cleaned up from the move.

The Arc isn’t going to work. The frame TV is so slim the sound bar sticking off the wall isn’t going to look right. My plan is switch to in-wall speakers. I haven’t done a ton of research yet but it appears to me Sonos doesn’t offer a surround sound in-wall system that doesn’t use a sound bar. Let me know if you have any insights on an in-wall setup. 

Hi

Glad everything worked out.

Sonos does not make an in-wall speaker system that will deliver Dolby Atmos sound. For that matter I don’t think any speaker manufacturer does at least not in the manner you envision.

It would require an Amp capable of decoding Dolby Atmos and also would require multiple speakers across the front (3) and others overhead and in the rear. 

The best you could achieve using a Sonos Amp to power two in-wall front speakers (Left/Right) and either Sonos in-wall or in-Ceiling speakers as rears (requires a 2nd Sonos Amp) is Dolby Digital 4.0 or 4.1 using a sub. In lieu of in-wall or In ceiling speakers Sonos Ones (x2), Sonos Ones/SL (x2) or Fives (x2) can be used as free standing speakers not requiring an Amp.

The center channel would not be dedicated as is with the Arc; but would be a Phantom Center created by the front left and right speakers.

I hope this helps