eARC problems with LG CX (Beam and Arc)

Hi @JM L., thanks for reaching out to the Sonos community and letting us know about your concern. May I ask, have you performed the steps we provided in this thread? If after doing all the steps and the issue is not resolved, it would be best to contact our support team for more in-depth troubleshooting steps. Please do not hesitate to reach out if you have further questions or concerns. We are always happy to help out.

Hello, I am having the same issue- Sonos ARC with LG 65oledCX. Original cable seems to work fine, but either lg or sonos is dropping hdmi arc connection by using different hdmi cable. I got plenty of hdmi 2.1 cables and somehow they aint working. I was wondering if sonos is restricting usage of other cables...

Following an incident involving a friend's toddler and his toys, my 4k TV now features a bright white illuminated crack across the screen.

As such I am currently in the market for a new TV and I want to make sure its fully compatible with my Arc and the rest of my Sonos array. 

The LG CX series seems to be the most likely contender based on price and features.

Can anyone confirm whether these TVs now have Atmos pass-through? (I have a HD Fury Arcana but prefer to not need it).

@DuranDoranMartell The LG CX is equipped with HDMI eARC and supports Dolby Atmos pass through.

@contractcooker - did you find a solution to your issue? I have an LG CX with the Arc and also noticed a signal drop from time to time. It’s a minor annoyance and switching off eARC isn’t really a workaround as you lose Atmos and the Arc doesn’t have any extra HDMI inputs for me to plug devices into directly.

What I did find was either a quick tv reboot or switching the audio source to internal then back to Arc solved it for me. I’d prefer a more permanent solution but this works until LG or Sonos release an update.

I’m having a problem with a new A/V system.

The sub and surrounds disconnect from the SONOS ARC when the TV is turned on.  If I power cycle the SONOS ARC the surrounds and sub reconnect most of the time sometimes I have to power cycle all the Sonos components. I also get the surrounds and sub to reconnect by turning off the TV and waiting about 10 minutes.  But as soon as the TV is turned back on they disconnect.

I only have this problem when using the HDMI eARC connection.  If I use the optical adapter the sub and surrounds don’t disconnect but I don’t have volume control and can’t use all the features of the SONOS ARC.

I’ve tried every fix listed on this site, none of them fixed the problem.  Also everything worked fine until I got updated by both LG and SONOS so I don’t know who broke the system.

OLED77CXAUA Firmware ver 03.23.15

SONOS ARC Firmware ver 13.2

SONOS ONE SL Firmware ver 13.2

SONOS SUB Firmware ver 13.2

Anyone have a fix out there?

That sucks. A few things I can suggest, although it’s pure speculation from my part. Can you try connecting all the Sonos speakers via ethernet, as well as the tv? 

I’m also on that firmware on my 65” CX and my Arc. I know there’s a beta LG firmware that's out for Dolby Vision gaming (probably among other things). You can try contacting LG for access to it. I’m also not sure if you can manually download an older firmware to go back a version so you can test - but might be worth checking out?

I made a mistake in my last post, the ARC does discount from the SUB and ONE SL’s when the TV is turned on and it’s using the optical port.  It just needs to set overnight with the TV off and when the TV is turned on it disconnects from the SUB and ONE SL’s.  The ARC continues to work otherwise and when the TV is turned off it reconnects to the SUB and ONE SL’s.  I can also get it to reconnect by power cycling all the SONOS components.  I’m using the IOS Sonos APP to monitor the ARC.  I’ve tried wired and wireless modes, it’s not an RF interference problem because I can get the system working by cycling power on all the SONOS components after the TV is on. Once it’s working it stays up until the TV is turned off for a couple hours and then turned back on.  Everything is pointing to a firmware bug in the SONOS components.

Is there a way to back up the firmware version on the SONOS components?

QuiXilver do you have a Sonos ARC connected to your LG CX?  Are you having problems with it?

Yeah I just bought the Sonos Arc a few weeks ago (my first Sonos product). And yes, it is connected to my CX via hdmi arc. I enabled eARC on the tv and set the digital sound out to Pass through. I've had minor issues:

• Netflix on the tv app sometimes stops outputting sound but it's only happened between episodes as opposed to randomly while an episode is playing. It appears the Sonos loses the hdmi arc signal. If I change the source to internal then back to hdmi arc it solves it. Or a reboot of the tv also helps.

• The same happened to my Xbox Series X once and if I remember correctly the same solution helped

• More confusing is my PS5. Sound stopped all of a sudden after me not changing a thing. I had to set the sound format from lpcm to dolby for it to work. But a better solution to keep lpcm was to set the hdmi audio in on the tv to pcm from Bitstream. 

But mine are minute compared to yours. I had a similar issue with a samsung hw-k950 soundbar some years ago. Rears and sub would disconnect from the main bar. I think mine was interference though hence my suggestion of wiring your setup.

I know it's a long shot but if you don't get answers from Sonos here, try reaching out to a youtuber Peter Pee or Jonah Mathes. They've done some great reviews on Sonos products. Peter’s is very in depth and I feel if anyone can help, it'll be him. I really hope you come right.