Going to try this Amazon.com: Lindy HDMI CEC Less Adapter, Female to Male (41232): Computers & Accessories

And if that doesn’t work then this  Amazon.com: HDFury Arcana: Electronics

Confirmed the HD Fury Arcana resolves the issue 100% so it’s definitely an issue with the lossy encoding of atmos over Dolby digital plus pass through over hdmi arc instead of eArc to the sonos arc. Likely some edge case between how Netflix encodes atmos and how LG and other manufactures pass through over ARC.

The Arcana splits the hdmi signal, sends audio to the Sonos Arc over hdmi eArc and video to the Lg over hdmi arc. I still have volume controls but now I also have upscaling, reliable atmos, and the ability to force HDR. Love it. Expensive, but worth it overall 

Still having this issue with my Sonos Arc + Samsung QE65QN95A + Nvidia Shield Pro 2019.

Sonos has concluded that the issue is with Nvidia Shield and the way this device is sending the audio signal from Plex over HDMI. Tried different framerate settings and tried the Refresh Rate app. But still no solution. Some much time spent troubleshooting. Really starting to regret buying the Arc..

I have an intermittent problem where occasionally the sound drops out for a second and then resumes. I have an Arc, two One SLs and a Sub. My diagnostic report is 1648205849. Thanks. MLS

Hi @MLS11 

Does all sound cut out in the room, or is it individual speakers that cut out?

First, I recommend you unplug the Arc, the Sub, the Surrounds and the TV from power. Once the TV has been off for 30 seconds, plug it and the Arc back in. Please wait until the Arc has a solid white light before plugging in the rest of the speakers.

If you have a WiFi access point (or router) in the same room, please configure it to only use one 5GHz channel, rather than it being set to Auto.

Thanks.

I have the same issue people here have cited. Freaking annoying as I'm in over 2k on my living room audio setup. The beam worked fine on my Samsung TV but the Arc cuts out every 15 minutes or so. 

Hi @CranjisMcB 

If you’ve tried rebooting the TV by unplugging it for a minute or two, I recommend you get in touch with our technical support team, who have tools at their disposal that will allow them to give you advice specific to your Sonos system and what it reports.

I am also experiencing this issue. 
 

diagnostic report number. 674104049
 

Hi @plundie 

Have you rebooted your TV by unplugging it from power for 3 minutes? If not, I recommend you do so.

It looks like rebooting your router will also do some good, but not specifically for TV audio.

If rebooting the TV doesn’t help, I recommend you try disabling CEC on the other device connected to the TV.

I hope this helps.

Although this issue exists on far more manufacturers products like my Hisense L9G….

New Sonos customer who had audio drop outs. My advice is to not overlook the basics…

The ARC is installed at the bottom of my TV (Sanus mount), and my TV is mounted to the wall with a full motion Sanus mount.

I tried so many things to fix the drop out, but decided to try a new HDMI cable. Fixed!

The Sanus full motion TV mount must’ve pinched the eARC HDMI cable when I was pushing the TV close to the wall.

I would never have believed that this was the problem. Man, was I relieved because I had poor luck with Sonos telephone support and was ready to return the whole system.

Hi, I’m having the same issue. It keeps disconnecting and defaulting to TV speaker. Please help.

@Noelzemail 

Have you tried the suggestions mentioned earlier in this thread, such as changing cables, switching off HDMI-CEC on each of the peripherals connected to the TV’s other HDMI ports?

If so, then perhaps contact Sonos Support via this LINK.

I won’t be buying Sonos again. Spent so much money on kit and my arc keeps cutting out

 Samsung and Sonos firmware updated yet and can’t even watch some freeview channels 

sonos support said to use the optical cable this was fine for a while but audio keeps cutting out. Wi-Fi is all ok in my house no problems there 

Avoid Sonos and Samsung at all costs 

The WiFi isn’t necessarily going to be relevant if you’re talking about the audio input from the TV, as that’s a cable connection - either Optical or HDMI.

I would check the TV settings and note with optical-audio, some codecs may not work, such as Dolby MAT/Atmos, so perhaps keep that in mind.

I would certainly ensure the Samsung TV is running on the latest firmware, as that may prove to be helpful too and consider trying a different cable/adapter, if you’re able to do that?

There’s still the option to speak with Sonos Support Staff too. You can always contact/chat to them via this LINK.

First thing I'd do is change the HDMI cable.  It's the only thing in both the HDMI-ARC and optical path.

same Issue Here. I Have Sony A80J , I cant watch any Movie with Atmos sound. 
 

What source App are you using? If it’s Netflix, then ensure you have their (higher level) premium subscription and that Dolby Atmos is shown near to the title of the TV/Show - Also what is the current audio output that’s showing on the now playing screen in the Sonos App when you’re playing any Atmos source?

@Nickkettt 

You perhaps may also find this thread helpful …

Thanks for answer. Not my issue. I see “Atmos” in the app. Also I have the same issue with the AppleTv . 

But the Cutting Off are anointed, I hope Sonos fix this. 

Yes. I have the Netflix  premium Suscripcion.
I see “Atmos” in the Sonos App when I play movies with Atmos sound. Is not the issue, I have Cutting off when its play movies. 
 

Thanks for answer! And I hope Sonos fix this issue. 

Have you tried switching the HDMI port from eARC to Arc to see if that solves your issue?

I had this problem about a month ago, and I went through the suggestions mentioned here, and then purchased 8K HDMI cables to ensure I have everything needed to run smoothly, and the sound cut out again last night watching HMO Max through ATV.  The movie was 5.1, although I thought it was a known issue with Atmos.  

Hopefully there is a fix coming soon, because the suggestion of unplugging all electronics is not a solution.

I have recently got the sonos arc

And it has been perfect for about 2 weeks

And i am now having this issue of the odd stop out for a few seconds quite regularly

Diagnostic report:

1347903807

Took me months to figure it out, but I have the answer!!!!!!

go to Amazon, buy the $11 cec-less hdmi adapter. I bought this one. BlueRigger 4K HDMI CEC Less... https://www.amazon.ca/dp/B07BFL8TM8?ref=ppx_pop_mob_ap_share
 

it’s perfect now. My wife no longer hates me.