home theater

You can only add two surround speakers to a Sonos home theater setup. So you would use a Sonos Amp to power the pair in the back and use as surrounds with the Arc. The front pair can either remain unused or you can get another Amp to power those speakers and use for streaming music on their own or grouped with the Arc/surround speakers setup. NOTE: You do NOT want to group the front speakers together with the Arc/surround speakers when playing TV audio from the Arc because it will result in a delay/echo effect.

that’s what I thought, thank you.

The problem with using the installed speakers as Surround channels is that then messes up Immersive audio if you are aiming to support Atmos!

Where are the installed speakers placed relative to your seating and is Atmos something you want to support?

SONOS is not designed to directly deal with this speaker arrangement. There are some options, each with positive and negative aspects.

• Ignore the second pair of speakers. Depending on their placement relative to your listening position, the second pair may distract from the surround effect. Surround speakers should not be located in front of the listener.
• Install a switch to disconnect the front ceiling speakers from AMP while watching TV. This will not mute ARC. You’ll need to setup and try this arrangement before deciding if this is good or bad. This is not the friendliest user experience.
• If ARC running along with the four ceiling speakers does not sound right, install a second AMP that will be used only for music and switch the ceiling speakers to this AMP for music listening. Again, not the friendliest user experience.
• Rather than fussing with a second AMP and the switching both pairs of ceiling speakers, you can switch one pair and use the controller App to somewhat adjust the relative Volume between front and rear. This is not a perfect scheme, your mileage will vary and, while avoiding the second AMP, there are still some user experience considerations.

The user experience considerations will affect each household differently. 

why would the in ceiling wired speakers connected to a Sonos amp mess up Dolby Atmos? The speakers I would use would be behind our heads in the ceiling. What would you suggest to support Atmos? Installing new speakers????

why would the in ceiling wired speakers connected to a Sonos amp mess up Dolby Atmos? The speakers I would use would be behind our heads in the ceiling. What would you suggest to support Atmos? Installing new speakers????

Are all four speakers located behind the listeners?

Essentially. There are two rows of seating and the speakers are in ceiling above each row. Based on everybody's feedback, I would activate the “2nd row” speakers as surround since we mostly sit in the front row. 

Immersive audio (Atmos) requires vertical separation between the ‘bed’ 5.1/7.1 speaker layer and the immersive overhead speakers, if your surround channels and immersive channels are all coming from the ceiling you can forget about any semblance of overhead effects.

Where you are using side or rear surround channels in an Atmos setup they have to be set at, or close to, your seated ear level.

Ahh makes sense. So to get the Atmos effect, I would need to put Sonos era speakers on stands at about head level (perhaps just behind and above the back of the chairs. Is that correct?