Likely the content is in stereo, which your TV then sends to the Sonos as is, rather than being in Dolby Digital 5.1. 

Thanks. I don't recall this occuring before. And for content... When I was watching the 4K Peacock NBC channel for the Arsenal game, all of the sound came from the Arc. So does that mean it's the App in general causing this? Because I feel that specific content should output correctly. 

No, if the Arsenal game was broadcast in stereo, not Dolby Digital, you wouldn’t get anything from the sub or the surrounds. The Sonos app (technically the speakers, the app is merely a remote control) doesn’t up-rez content. You can look at your controller to see what signal it is receiving. There also could have been a change in your TV’s settings, might be worth double checking that it’s set to ‘pass through’ or as close as the TV you own is allowed to not change the audio signal. 

The app still says Dolby digital plus when watching on YouTube or YTTV. I'll check my TV settings again but didn't notice any change yesterday. 

So switched to YouTube TV on Firestick and my rears work. App says Dolby Digital Plus 5.1. 

Says the same thing when I'm on PS5 and YoutubeTV but sound is only coming from Arc. 

Seems like a PS5 App issue...I guess

Maybe I just don't understand. But on the Sonos App when playing YouTube or YTTV or Peacock on PS5, it says Dolby Digital + 5.1 but the sound is only coming from the Arc. Sports,  cartoons, The Office you name it. 

But I can switch right over to my Firestick and play the same live content and get sound from my rear speakers. Still shows Dolby Digital+ 5.1

The PS5 issue is new. Was it true 5.1 coming from those shows...probably not but the Sonos app shows it is.

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