I would check your TVs audio settings and remove any additional processing it may be adding in.  You want the audio to just pass through.  

No settings to allow audio pass through unfortunately. Bitstream or PCM my only options.

Changing the audio output to stereo uncompressed on the xbox resolves the lag issue but sounds much worse.

Would a HDMI splitter with audio pass through solve the issue? I’m hoping this would bypass the TV and remove the delay but I’m not 100% that will work.

To make sure we are clear, you’ve looked at the audio settings on both your TV and xbox?

No, this won’t work.  The audio Sonos needs is coming from the ARC/eARC (Audio Return Channel) which actually flows backwards from the normal flow of video and audio on an HDMI cable.  Additionally the only thing that can generate an ARC/eARC signal is a TV or the HD Fury Arcana.

There absolutely have been cases where TVs introduce a delay in the audio, and you can’t really get around it unless you bypass the TV by using Arcana.  I can’t say for sure that’s what’s happening here.  It’s also possible that xbox series x is the problem, but that is unlikely as I don’t recall any other cases where it was the cause of a delay. Bitstream should be the proper setting, and was for my xbox one s with a Samsung TV and Arcana with an Arc or Beam.  

That’s correct. I’ve attached some pictures of the settings for reference. After some reading it seems a lot of Xbox users have experienced audio delay when using bitstream out.

Did you have to purchase the Arcana too? It feels like I either need that or a TV upgrade which isn’t ideal after spending £450 on the soundbar.

Thanks for your help by the way it’s much appreciated.

I have one setup with an xbox, samsung TV (ARC), and beam gen 1, no arcana.  Works fine without delay, but I obviously don’t have atmos.  I want to say my settings are a little different then yours, but I’m working from memory, and I do not have the exact same model TV and xbox as you.  If I remember, I’ll try and have a look later tonight.

On a second setup, I have an xbox, samsung TV, Arcana, and Sonos Arc.  Arcana was needed to get atmos out of the xbox and blu ray disks in the xbox.  My TV is not eARC.   I wouldn’t need it if I had an eARC TV, but I probably would have gotten it anyway as it simplifies the setup and has some video improvements as well.

Others, please chime in..

I’m having the same issue and the only fix is to use Stereo Uncompressed from the Xbox. It’s such a shame as when Atmos is switched on it sounds incredible but the delay is nearly 500ms+.

I have the Beam 2, Xbox Series X and the Samsung UE43TU 4K TV. I’m using the Beam over Optical Audio (which doesn’t allow passthrough but still seems to be more in sync than eARC). It’s a real shame because I am not using the Atmos on the Beam at all because it’s just unusable currently on XBox. It’s out on other apps too but I can fix that manually. 

Having done some reading, it seems like the Series X is the problem and those who have both Series X and PS5 don’t have the issue with their PS. Will it ever be resolved? It’s such a new console you’d think MS would be all over it but doesn’t seem to be the case. I’ll be keeping an eye on it but I won’t be holding my breath for a fix any time soon – will have to just stick to Stereo Uncompressed.