Sonos Arc wall mount: How to fit outlet and low-voltage behind the mount?

As to the depth of the Arc below the TV, this would seem to depend upon upon how far the TV and how thick it is, off of the wall.  I plan to mount a very thin LG 65” GX model at only 0.8” off wall above the Arc.  Is there a suggested distance below such a setup?  I would imagine a table such as if the front surface of the flat panel is 3” off the wall, the Arc should be 4” below, if the front surface is 2” off the wall, then the Arc should be 3” etc.  The 4” recommended spacing below the flat angel in the documentation is devoid of detail.

In my new construction design, I want the soundbar to be just below the LG flat panel, and wi th only 0.8” depth of the GX flat panel, I don’t believe it will impede the upward firing drivers for Atmos?

Best demo below and recommended 4”. My Sony 65” X950G is pretty flush considering, and the extra 2” made a hell of a difference. Atmos drivers need care 

I’m sure it’s not the ideal solution, but you could use a raceway to hide the wires.  I’ve done that with the Beam and was fairly happy with the way it turned out, after painting to match the wall.  

And keeping the Arc significantly below the TV is not just about the up firing speakers, but accessing the controls on the top.

If the back surface mounting side the Arc was co-planar with the front surface of the flat panel (with a .8” spacer behind the Arc). Would the Arc need to be below the flat panel by 4” still?  I’m looking for some laws of physics explanation as to the actual dimension variability.  My goal is to clean up the look of the wall by not having a gap between the flat panel and Arc (I know this is subjective as to what looks ‘good’)

I have a great installer.

Things were going perfectly ‘till we tried to plug in the extra short C7 cable. The standard male will not allow a flush install. Way to go Sonos! 
 

So, jury-rigged for now, with C7 with flat male on its way. 

( For future search-ers on this topic, audiophilia published a follow-up thread here: https://en.community.sonos.com/home-theater-228993/arc-pro-install-after-three-months-6847482 )

I’d like to have the soundbar as close to the TV as possible for aesthetic -- tying to keep the fireplace wall as clean as possible -- sort of have the flat panel and soundbar as one unit.  The 4” spec is still confusing me as to if it is a spec for spatial separatation in general from the screen or purely to insure that the soundbar up-firing speakers are not physically impeded from firing into the ceiling for the full Atmos effect.  Here is a side view of what I thinking of doing with a metal shelf (since there is a fireplace below ~18”) that would have the Arc have a free ‘view’ of the ceiling to fire against for Atmos effects.

Heat management is also a question...any opinions by the group on this concept?

The shelf will be non-combustible (debating this if best to be metal or something (a composite) that doesn’t itself get hot like a hot plate even though it is deflecting the heat away from the flat-panel in so doing).  I have 18” between the fireplace and the bottom of the bracket/shelf.  The shelf will be the same dimension as the Arc.  The flatpanel will be LG GX 65” which is 0.8” thick off the wall when mounted flush.

Thanks all for the constructive feedback!

[All below IMO of course]  I think audiophilia’s cautionary response to your first message above is true in his/her case, but mis-explained.  The position is important, but more for overall room and seating position; that 4” vertical helped was likely due to where the audience’s ears were placed!  Two things at work: (1) On-axis sound from the forward-firing drivers to the audience’s ears, and (2) the reflection angle for side & up-firing drivers which should in theory also go straight to the ears.

You might find the YouTube video from Peter Pee where he actually checks the up-firing angle and calculates reflection, then measure your own ceiling height and sofa offset.  You could shim the shelf to get it close to optimum but that messes with the direct sound angle too.  I would rather get the main direct sound aimed at your head(s) and let the other channels fall where they may.  Yes, the sound is expanding from a point source, so it’s not like people will be totally missing out if you don’t, but off-axis the timbre changes.  (As a verification that this matters, consider the many center-channel speakers in L/C/R home cinema systems which have threaded screw feet to tilt the speaker.)  I think good sound is worth more than a clean fireplace wall, if it were my own installation.  Center of screen just below seated eye level, and speaker aimed slightly up.  Yeah, I know this isn’t what you have drawn, and it cannot be.  Even with the horizontal gas-insert style you have drawn, it’s still too high.  Bummer.

As to the heat issue, well, see my flames (ha) above and put the TV elsewhere!  Seriously, though: Conduction, radiation, convection.  Detail the firebox wall to prevent all three from affecting your screen, which is probably more at issue than the Arc.  Convection: you could put an HVAC outlet in the ceiling centered over the fireplace?  Radiation: maybe chrome-plate or polished stainless shelf instead of black anodized?  Conduction: switch to one of those chimney-less gas fireplaces?  Not bloody likely…  Just fix the details behind the drywall, since you’re intent on mounting the screen flat/flush.

Tracker,

Thanks -- it is a combination of constraints and compromises.  

The fireplace is a gas/chimney-less (self venting style).. so I am less concerned about heat from within the chimney as there is none.  It does seem that the 4” spec is written with an assumption that the screen is at seated eye - level which will never be the case in any fireplace install.  I have another more proper madia room in this condo that will be much easier to accommodate (and I will).   It is the ‘above fireplace’ install that many people unfortunately have to do for their great room to ‘work’ that I am trying to solve and in doing so, hopefully help out a lot of other people.  Many people don’t even think about the heat issue...simply put the flat panel above the fireplace where it fits.  Atmos is another new feature that adds some constraints.  It will never be perfect!

I’ll look for that YouTube -- thanks for the pointer/suggestion