Hi @Mark farragher 

Welcome to the Sonos Community!

Lip Sync may rely on the exact model numbers, and the exact software versions on them, so it is difficult for anyone to say “this will work” or “this will not work”. Especially when three devices are involved. What I can tell you is that LG OLED lip sync issues that have been discovered have been reproduced on multiple brands of soundbars. This issue was only seen with standard Dolby Digital sound tracks. The fact that this works on your Playbar without issue suggests you won’t have any problems with the Arc (though it is a different physical interface, so I can’t be completely sure).

As you are in the EU, you will have a 100 day Money Back Guarantee return period on the Arc. This means if you do have any lip-sync issues, you will have plenty of time to try various settings, ask for and receive help here or from our support team, and if you can’t resolve it you can simply return the Arc - we pay for all shipping costs, so the most doing this will cost you is your time.

Keeping the video and audio in sync is the TV’s job - only it knows how long the picture will take to render, and the audio should be delayed by the same amount. Your brother’s Arc will be playing audio as soon as it gets it, so I recommend he look in the direction of TV firmware updates and trying alternate sources, if available (use the Netflix app on the TV instead of the one on Sky Q, for example). If your brother has not been in touch with our technical support team, I recommend he do so.

I hope this helps.

Thanks very much I’ll try this and let you know

thanks

mark