I can confirm that all sync issues have been resolved by switching to the Sony ht-st5000...bye bye Arc. Clearly the direct audio route is the only option to avoid sync issues between the sky q and the LG oled. 
Shame the Arc didn’t work as it was a good one box solution...just had to make sure the Sony subwoofer is hidden.

So, you did have sync issues, I take it. I am not familiar with that sound system but I guess you connect everything to it and then send the picture to the TV set?

Has anyone tried the C8 / E8:s built-in Netflix app with the new Sonos Arc playbar? Any sound delay with Atmos? Also when playing atmos content from the USB-input, any delay?

I have an LG E8 (arc only) and will only use it with the native netflix app+USB content, and not sure if the Arc would work with that or not for atmos without lipsync issues.. 

No (current) noticeable lipsync issues from builtin Apps with Arc on my Series 8 (DD 2.0, DD5.1 DD+ & ATMOS). Some ‘just about’ tolerable issues with ATV4k, but I use builtin Apps mostly.

Thanks, thats reassuring - I might just go for it then! I will have to blind buy it though, no way to test it in my country. Are you happy with the sound? Do you get a decent atmos effect from Netflix stuff?

I don’t think you will get a ‘decent’ Atmos effect from any soundbar. The dolby demos may trick you visually into hearing things ‘around’ you from soundbar, don’t set your expectations too high for Atmos from a soundbar, and you wont be disappointed. With Sub, I’m happy with sound for movies, but even when I’m happy, I could be happier :)

Heres an update. Bought the Arc and have had for about more than a month. Frankly it underwhelms coming from a Vizio 36512-F6 which had Atmos, but rears and a sub too. It does sound good, but at this price point it’s a disappointment. I have Apple TV → C8 —> Arc. The S2 app reports I’m getting atmos. Works on D+, Netflix, and Apple content. 
 

My living room setup is not optimal for Arc’s side speakers. But the worst issue is the lip sync audio delay. When I first set it up I noticed a very minor sound delay. Disappointing, but I probably would have forgotten about it. But over time the delay gets worse. Can’t isolate why, but the sync is off by maybe a second. Unwatchable. Restarting Apple TV or just the offending app usually returns to default minimal delay. No adjustment on C8 or ATV (very few available) improves this. 

i see posts saying you can’t get atmos in this setup, others that there’s no sync issue, and still others say the sync issues are across TVs and even with eARC. Not sure what to think. I’m waiting for contact from Sonos support. Right now I’m thinking of returning it. Tremendously disappointed. 

Hello everyone, first post on this forum, but I have been battling trying to get Atmos working on various devices for probably 3 years now.

It started with a Vizio 65 of some sort, ARC, and a Samsung HW-K950.  Atmos worked, but there was an incompatibility between the Vizio and Samsung where the audio would “hollow out” periodically.

So, I went to an LG OLED C8 and an Apple TV 4k and an Samsung HW-Q90R and get pretty consistent Atmos if its available, but the sound’s never awesome; the sub on Q90R now sounds like its dying and becoming raspy and its not 2 years old yet.

Why do I mention this on the Sonos forum?  After reading several threads here along the vein of ‘will Atmos work’, I cancelled my Arc, One SL pair and Gen3 sub order because this sounds like more of the same that I have battled over the years.

I was under the impression that Sonos would have these things worked out, but it really looks like they’ve hung their hats on eARC and that’s a battle I’m not going to fight.

I see where people have claimed to get ATV4K → LG C8 → ARC → Sonos Arc and get Atmos, but they are either underwhelmed/uncertain they’re getting real Atmos or experience audio lip sync issues.

I am here on the hope that multiple someone(s) can confirm that ATV4K - LG C8 - ARC - Sonos ARC actually produce a trouble-free experience, though I assumed the grass was greener on the Sonos side of the fence and it seems it isn’t, unless I want to augment the 2k Sonos theater setup with another 4k eARC-capable TV.

Either way, thank you forum members from saving me a ton of buyer’s remorse after pulling my hair out over a 3rd year trying to get decent Atmos sound!