Configuring them as a surround sound system will make them all one room and you never need to configure anything again.  

First, setup the Arc Ultra: https://support.sonos.com/en-us/article/set-up-your-sonos-arc-ultra

Then setup the Amp, adding the Amp to your existing system: https://support.sonos.com/en-us/article/set-up-your-sonos-amp

Then add the Amp as surrounds: https://support.sonos.com/en-us/article/add-surround-speakers-to-a-sonos-home-theater

Then setup the Sub and add it to your Home Theater room: https://support.sonos.com/en-us/article/set-up-your-sonos-sub

Thank you. I will give this a try tomorrow.

jgatie-

I followed the instructions provided and have landed on a system that looks like this:

• Room: TV Room
• Products: Arc Ultra; Amp (as surrounds); Sub 4
• TV connected to Arc Ultra via HDMI.

I get in-ceiling speakers working seamlessly with music; however, not getting sound from them when TV is the source. Have I missed something or is there an easy way to add the in-ceiling speakers when watching TV?

Thanks again.

The TV has to be configured for Dolby Digital output (often called “Bitstream” or “Passthrough”).  Then you must be playing a DD or Atmos source file. On my 2023 Samsung, I have it set to “Auto” and “Passthrough” under Audio > Advanced Settings.

Note:  Surrounds for TV will be very different from surrounds for music streaming from the Sonos app.  Surrounds for TV give atmospherics and/or directional effects and will not be playing at all times.  Surrounds for music just repeat the stereo R/L channels. 

Also note:  For sources, choose something like Disney+ to test Atmos.  Other sources require an upgrade (Netflix, Max, Prime) for Atmos.  Avoid YouTube videos to test audio.  Even if they are marked Dolby Digital or Atmos, they are really 2.0 stereo because YouTube converts all free videos to stereo to save space.

Many thanks for the advice.

I have the same problem, but an older Playbase as Center, L,R, a Sub 2, and A new Amp just purchased from Best Buy, compatible with ceiling surround speakers.  For example, I can separate my Amp with connected speakers and play music on them from Amazon Prime.  I never hear anything from my surround speakers when I add the Amp to my Theatre System.  When playing my television, the source would begin at Netflix, Amazon Prime, Disney, etc., go to my television over the Internet, from the TV to my Playbase via a fiber optic cable.  The output on television is set to Dolby Surround.  I assume the Playbase isn’t sending the rear surround signal to the Amp, as the Sub (2) works fine. I have tried all wired, then changed to wi-fi while leaving the Ethernet connected, no difference. Did you ever receive a response from support?  I am not sure what happened to Sonos support, but unfortunately, it isn’t exactly what it once was. I have spent hours and gotten nowhere, explaining the same things repeatedly. 

I don’t think the Playbase supports Amp for surrounds. 
 

When you try to Add Surrounds, is the Amp an option?

Yes.  

I stand corrected! 
 

When you stream music from Spotify, Amazon or other source do the rear speakers play sound?

Are you sure the Playbase is receiving a DD signal? Not all programs are transmitted in more than stereo/DD 2.0

Edited to add:

If you select the room, what is shown as the input signal format - it’s to the far right of the “SPDIF” data? 

When I was using the test Movies using Amazon Streaming, it stated, “Dolby Digital 5.1.” If I switch from Amazon streaming to watching a podcast or the news on YouTube, it is Dolby Digital 2.0.  I don’t need surround sound on the news or podcasts, and I don’t think YouTube broadcasts in “Dolby Digital 5.1” 

Most YouTube videos are changed to stereo, for storage space considerations by YouTube. My understanding is that it’s only the TV subscription provides potential ‘larger’ files. Anything uploaded by a common ‘user’ is suspect. I don’t think they really know, I suspect it is explained in the user agreement, which of course, no one reads. 
 

Some things on regular YouTube such as 

Are in 5.1.  More things on YouTube TV are in 5.1, but it varies.  Things you would expect on Amazon, such as Movies, are in Dolby 5.1.

In my experience, even the videos marked as DD 5.1 or Atmos are downgraded to 2.0 PCM.  There are very few (if any) on the free subscription YouTube that are actually 5.1 or Atmos, even when marked as such.

Within YouTube, if I change from a typical video, I can see my Sonos iPhone app audio signal change on my screen from Dolby Digital 2.0 to Dolby Digital 5.1.  After giving up on support and playing with different combinations, Dolby Digital 5.1 is now working with my Play base, Sub (Version 2), and latest iteration AMP, running the rear surround channels.

Playbase

Connection

An Ethernet cable, wired to your router, is required to allow Wi-Fi to be disabled.

Disable Wi-Fi

Enable Wi-Fi   

Amp

Connection

An Ethernet cable, wired to your router, is required to allow Wi-Fi to be disabled. 

Disable Wi-Fi

Enable Wi-Fi   

Sub (Version 2)

Connection

An Ethernet cable, wired to your router, is required to allow Wi-Fi to be disabled. 

Disable Wi-Fi

Enable Wi-Fi   

​@Scott Gibbons When I watch the YouTube video you link I get this:

This person seems to have had the same issue that you are reporting, but was able to resolve it by changing settings within their television. See Sonos case below.

app shows stereo pcm / 2.0, but using eARC and surrounds

Hi

I have a sonos Arc and 2 Sonos one SL as surrounds 

The app says its playing stereo pcm and in the settings that the arc is receiving stereo 2.0

However, I'm running a brand new 55 inch LG oled TV and the arc is connected via a eARC hdmi cable.

The app shows that the audio is set to surround and the rear speakers are working.

But when I stream dolby atmos from Disney plus the app still says its receiving stereo

So ... I have connected it properly, I'm streaming dolby atmos, the TV is running the audio out correctly to the arc sound bar, the rear speakers are connected correctly, the app shows the sound mode is set to surround,  but on the about my system and the player on the app it says clearly its running stereo pcm…

How do I get this set up to run atmos?!?!

Pinned reply

Hi buddy,

Its a cx series LG OLED

However, after some exploring I found there were some additional setting in the tv's advanced sound settings that had not activated,  ... I changed them to dolby digital plus and pass through and it seems to have worked!

Full atmos and also 5.1 on other services 

Job done…

Tbh,  I wouldn't have worked it out if I hadn't been reading for round in these forums.

Thanks chaps

Moderator edit: removed picture showing personally identifiable information and increased legibility by removing platform metadata and adding link to thread.