Sonos just plays what it is sent.

It is the Apple TV or the YT app that is doing this (obviously Sonos have no idea you changed the channel) - what are the audio settings on the ATV? Does YT have any settings?

The interesting thing is the Sonos IS being sent 5.1 and decoding 2.0 (confirmed using the status for nerds and Sonos verified this using the logs). 

Audio settings at ATV is set to Atmos if available (limited setting here) and YTTV set to 5.1. I’ve also experimented with the TV settings and same problem (although it might be PCM 2.0 vs. Dolby 2.0 on initial launch of YTTV app).

What channel does actually have 5.1 sound? I’m happy to test that out, but I also don’t think this is a Sonos issue. Even if stats for nerds show 5.1, it just shows that the YouTube video has 5.1 but not necessarily that the ATV also sends that to the Arc. 

All the local channels in my area (ABC, NBC, CBS, FOX), most news and sports networks have 5.1. Another note, I didn’t have this problem with a Sony receiver (ATV connected to receiver, receiver to TV) and it seems to work without the issue using the YTTV app on the TV.

Appreciate any assistance!

Ok, I’ll have a look but not sure I can get these channels since I’m based in Europe. Also it’s a bit surprising these channels would have 5.1 sounds, that’s not really common for news channels. For sports it’s different of course but I’m sure I cannot get these here in Europe due to geo restrictions. 

Understood and thank you. 

So I have tested ABC and NBC now and both don’t give me any 5.1 sound at all, the Sonos app always shows Stereo PCM (which I would expect as mentioned earlier). It’s still a bit odd though since you seem to get 5.1 sound. I have also tested a channel that has 5.1 movie trailers and that works as expected and 5.1 sound is played immediately.

So it’s a bit of a mystery to me and I don’t think I can help much to be honest, but I wouldn’t expect any 5.1 sounds from news channels anyway so I’m wondering if there is some kind of transcoding going on and either the ATV or the TV do something with the sound.

As I recall, the local affiliate for CBS in Austin, Texas was sending my system a 5.1 Dolby Digital signal during the pre-season games for the Dallas Cowboys. Unfortunately, the network feed they were being handed was a stereo feed. This caused a lot of oddities in my sound, with Sonos appropriately reporting it was receiving 5.1, but the playback was in stereo only, and somewhat muffled and frankly almost unlistenable. But it wasn’t Sonos at fault, it was the station, sending a stereo signal across a 5.1 carrier. All other sources, both on my Apple TV and DirectTV (at the time) functioned perfectly. 

Hi ​@mattob 

Welcome to the Sonos Community!

Sorry to hear of this issue you are having with receiving stereo audio when playing YouTube content through your Apple TV to your Arc Ultra.

We were able to reproduce this issue in our own testing and it seems that the Arc Ultra is just playing what is handed to it - the cause of the issue lies elsewhere, as the TV is outputting stereo audio.

I recommend you contact Apple for further support.

I hope this helps.

Hi ​@Corry P - Thanks for reproducing the issue. When I spoke w/ the tech support staff via a consultation, it was confirmed 5.1 was being sent to the Arc Ultra for our tests. One note, It’s YouTube TV (vs. YouTube) is the topic. The Sonos rep also mentioned Sonos would contact Apple as well.

Many thanks.

I don’t have any experience with YouTube TV, but all of my experience with YouTube directly is that they reduce the uploaded content to stereo, and strip any 5.1 content along the way. Contrary to what a lot of the videos claim. So anything that I ‘watch’ from YouTube is assumed to be stereo (and I’ve not looked at what Sonos gets from my TV anymore..if it’s from YouTube, it is always stereo). Apple TV is my source, for what it’s worth. Apple TV does not ‘upscale’ the content to 5.1 or Atmos. 

Hi ​@Airgetlam 

With a YouTube Premium account, you can get videos that have 5.1 surround sound. I don’t know if YT support anything better than plain old Dolby Digital, however.

While it is mostly pay-per-view movies that have surround sound, some of the channel testing videos do have surround - not that we recommend using them to test with, of course.

With unpaid-for YouTube, I think it is indeed all in stereo.