Head height, or ‘arguably‘ just very slightly below, is the ideal position.
 

Some folk use ceiling speakers as rear surrounds which, personally speaking, I don’t like, as I don’t like some parts of TV sound from above. I’m okay with ceiling, or high-up audio maybe as background music audio, or as part of atmos(pheric) TV surround sound, but not as front. or rear, audio.
 

Because of certain limitations in my own living room, my rear surrounds are about 6 to 8 inches below head height and I notice that the audio is coming from slightly below my seated position, so you will undoubtedly have the experience of the rear audio coming from above… the question is whether you can live with that and if it suits you, the aesthetics of the room and keeps other family members happy too.
 

Ideally though, head-height or thereabouts, when at your seated position, is most probably the best place to put them.
 

I’ve just realised too, that you are using the Arc as your front device, which supports Dolby Atmos, so that will be reflecting two front audio channels off your ceiling and so my thoughts are that putting your rear channels high aswell, might ‘muddy’ the intended sound stage as Atmos is there to immerse you in spherical 3D surround sound and placing the rear speakers high up behind you is likely to harm that intended listening experience. However the answer might be to somehow try these things and see what your own thoughts are.

Thanks.

That was my worry also.

I just picked up a new system and am going to mount the one sl’s at ~head height on the wall behind my sofa (its right up against the wall)- based on alot of the advice I’ve seen.

But one thing I’m pondering is when the one sl are mounted on the wall- will it matter much if the speakers are facing out perpendicular to the wall or should they be pointing inwards slightly?
I guess this will influence the decision on which wall mount I go for.

Am I overthinking this? 

I have the same question as @L44YEK .

Also if I choose to put the one SL’s on shelves/stands on both sides of my sofa. Do they need to face to the tv or to my ears? as my sofa is against the wall. Or is wall mounting preferable? Same question: do they need to face the TV or 90 degrees turned, to my ears in a straight line. 

Thank you,

This is what Dolby recommend. I’ve used a 5.1 setup as the example here:

https://www.dolby.com/about/support/guide/speaker-setup-guides/5.1-virtual-speakers-setup-guide/

@Ken_Griffiths As said in both posts, the sofa is right against the wall, so we cant use your link. 

Looking at pictures etc Sonos themselves seem to have speakers facing the TV, so in this case perpendicular to the wall behind the sofa.

I’ve decided I will wall mount (ear height when seating using a bracket that gives me the option to turn toward the central seat.
Saying that I think I will have them facing straight out from the wall most of the time.

ps the heigh I have chosen is based on the Sonos One Stands.

Hi @L44YEK.

Welcome, thank you for reaching out to Sonos Community, We appreciate your time and effort in posting your concern here in our community.

I hope this thread might give you an idea of setting up your Sonos arc placement.

Let us know if it works. If you need help with any other information, please be sure to let us know.