If it’s LG WebOS, then perhaps goto the TV ‘settings/connection/hdmi device settings’ and switch off Simplink and you should then (hopefully) be able to switch inputs away from HDMI-ARC to another option in the sound-out list.

Actually I did it, but after a few sec HDMI-CEC fuction switch back on as well, so I really frustrated, because this would be the solution but do the same thing as the sound settings. Would it be an LG Tv bug?

You could try to turn eArc off first.

I have the LG C9 TV and it only switches back to the HDMI-ARC/eARC port if I do not disable ‘Simplink’ - if I disable Simplink first, then I can switch to any other output such as TV speakers, headphones, Bluetooth etc. If your TV isn’t doing that, then perhaps contact LG support and see what they say, but it’s working okay here.

Ken thx. I got the right answer from you. I believe it should work properly and yes could be the problem with my TV, cuz it has no make sense that the HDMI-CEC function turn on automatically if I turn it off.

Really appreciate your answer and time  

Hi fejo89, did you find a solution to your problem? Same issue here and it gets so frustrating I am planning to return the Sonos Arc system. I would prefer finding a satisfactory workaround other than unplugging the hdmi eARC, which is what Sonos support suggested to me.

This is driving me completely bonkers.  Not only does it prevent me from using bluetooth headphones without turning off or disconnecting the Arc but it also fudges the video handshake with my XBox making me go into the menu to turn off simplink every time only for it to re-enable itself seconds later.  So much for communication standards.

I seem to remember eARC must be turned of to keep Simplink turned off.

Isn’t eARC necessary for Atmos? Seems to defeat the purpose of purchasing a high end soundbar if that’s the solution. Appreciate the response.  

Yes eARC is necessary for Atmos. I also have this problem with an LG G2 TV. Its so incredibly frustrating. I feel like Sonos needs to talk to LG to get this sorted out. This problem has plagued me for over a year.

eARC is not necessary for Atmos.  You can get Atmos from Dolby Digital+, which 95% of the streaming sites and/or streaming devices use, and it is available over HDMI-ARC.   The only devices/media which require eARC are Apple TV and Blu-Ray discs.

Sorry I should have been more clear, eARC is required for bitstreaming Atmos in full quality, not the inferior version used by streaming sites etc. 

I think ‘inferior’ is a judgement call. How many speakers does the average person have? The ‘compressed’ version has all the necessary channels for 99% of home installations, including Sonos. 

Subjective adjectives aside, I stand by my correction.

I have the unfortunate combo of LG C3, Apple TV, Arc, and XBox.  I’ve given up on easily switching between these devices or using Bluetooth headphones from the TV despite it running GeForce Now quite well.  I’m going to order an 8k HDMI switch to remove the Arc from the system during some scenarios as taking 15 minutes to go through the menu and restart dance makes getting ready for a gaming session a bit maddening.  

You should have said 'lossy' compressed but yeah sure.

There’s certainly no indication in the Wikipedia article about the Dolby Digital Plus version of Atmos being lossy. What’s your source?