There seem to be a lot of threads and conflicting pieces of information out there and looking to share what I know and get input from others. 

For convention. Arc refers to the Sonos device and ARC to the protocol (they couldn’t have picked a more confusion name). 

My TV is a Samsung Series 6. Nothing too fancy but a great device and has ARC but not eARC. I know there are many out there with similar setups. 

I have an ATV 4K going —> HDMI 1 on the TV. I have the TV ARC going —> Sonos Arc. 

With just the one input on the Arc I don’t see any other way to configure this. 

I have the full UHD subscription in Netflix. I’ve tried a few films that I’m told have Atmos but I don’t see that showing in the Sonos app. 

I’ve been told by some experts that ATV 4K can’t send this info (regardless if it’s Netflix or any other source) over ARC to the next device. As such, basically I can not expect any Atmos with my setup. 

I’ve also read many posts explaining that people are getting Atmos over ATV 4K into a Sonos Arc without eARC. Given that the Arc only has the one input, I have to assume a similar setup to mine. 

So that’s what I know. Love for others to weigh in and help. I’m hopeful that this can be a thread that future enthusiasts can turn to for help as well. 

Finally, a small oddity. When browsing the Netflix catalog, I have never seen the Atmos logo. I’ve seen 5.1, UHD, Dolby vision and others, but not Atmos. Most recently I tried episode 1 of season 3 of stranger things, having been told it has an Atmos track. Maybe I’m having a separate issue at source, rather than in my configuration.