Hi ​@Wulbo 

Welcome to the Sonos Community!

Sorry to hear of this issue you are having with the audio and picture from your Windows 11 machine being out of sync.

Not only do I have an Arc Ultra, but I also have my PC connected to my TV and have Atmos working (on Windows 10), but I have not noticed a sync issue (when playing games - the Windows Sound configuration screen where you can click on individual speakers to hear one play is a bit slow). Notice that I said “noticed” - I have been playing the sedate Farming Simulator 22 recently, and something tells me it’s not the best game to determine this with.

It looks like you just gave me an excuse to start playing games when at work…

OK, so I just tested this by getting Indiana Jones to punch a wooden box a few times - I can’t perceive any delay.

As it is the TV’s job to keep the audio and picture in-sync, I recommend that you unplug the TV from power for at least a couple of minutes, as doing so will force it’s software to restart in a way that standby does not achieve.

It’s probably also worth ensuring your GPU drivers are up-to-date, just in case. I’m not familiar with AMD GPUs, but the audio driver for nVidia GPUs is included with the graphics driver.

Finally, please try a reboot/restart (note that a Restart from within Windows is going to actually restart the kernel of the Operating System, where as Shutdown just saves it’s present state to be reloaded at power-on) of Windows.

I hope this helps.

Hi Corry, thanks for the response. I’ve tried everything u said there but no luck, it’s still out of sync . I don’t have EARC I’ve only got an ARC port, do u think that could have anything to do with it? When I turn atmos off on the pc everything is synced up perfectly.

Hi ​@Wulbo 

Ah! I do think so, yes.

Dolby Atmos can be delivered as compressed Dolby Digital + (Atmos) audio, or as uncompressed Dolby MAT. The latter requires eARC.

Although I could not find anything to confirm it with a quick search, I think Windows will most likely deliver uncompressed Dolby MAT as I know the game consoles do, and Dolby MAT is “easier” for a game/computer to deliver, due to it’s object-based, rather than channel based, mapping system, with little extra overhead.

Do you actually get surround sound? Is “Atmos” reported in the Sonos app while playing? If so, it sounds like the computer might be generating Dolby MAT and then converting it to another format, introducing the delay. This would surprise me, however - I would have thought you’d be more likely to just get stereo or silence.

I hope this helps.

Yeah when atmos is turned on in w11 I do get atmos but it sounds about 250 milliseconds off. When I turn atmos off in w11 I get stereo but it’s in sync.

Hi ​@Wulbo 

Well, if your TV does not have eARC, then your Beam must be receiving Dolby Digital + (Atmos) which your PC may refer to as EAC-3. My assumption is that there is a conversion (transcoding) going on, and that will take a little time.

One option might be to try and force the TV to do the conversion instead (tasks done in hardware are quicker than those done in software), but if it does not have eARC, it may not support Atmos. Worth trying, however - please ensure that your TV’s digital audio output format is set to Auto in it’s Sound settings, or to Dolby Digital + if Auto doesn’t do it.

No guarantees, but this is your best chance, I think, short of getting a new TV or an Arcana to provide eARC (only a TV is supported, to be clear).

I hope this helps.