Have you tried disabling eARC first and then disabling Simplink?

This is a function of CEC (Simplink), and not particular to Sonos. I’d second @GuitarSuperstar ‘s suggestion. 

I have the same issue. Is there any reason eARC actually needs CEC to work?

I have the same issue in my C2 and Sonos Arc setup.  I have tried to contact Sonos and LG but both couldn’t fix the issue. 

I have the same problem. Cannot not switch to any other audio out like Bluetooth headset without tv switching back to ARC about 2 sec later. Any update?

Turning the ARC autoplay off down not prevent this. 

Typo, I meant to say turning the Arc’s Autoplay off did not correct this. 
 

My work around has been to unplug the Arc’s HDMI plug then any other audio out selection will stick. 

I have been bugged with this for a very long time. My solution: go to settings > all settings > connection > device connection > disable auto device detection and simple link. This will enable you to choose another sound output source. This will work till you switch back to ARC source again. I use Sonos arc and had the problem of switching automatically to sonos arc. Now I can use my BT headphones when I want. Sadly this method has to be restarted every time you switch back to hdmi arc. Try and let know. If anyone else finds a different and stable fix please let me know. 

Glad to know I’m not the only person with this issue.  I keep praying for an LG or Sonos update to fix this.  Essentially I end up “fighting” with the TV.  The only way I can get things to work is just try over and over again-- either to a.) turn SIMPLINK off - it wants to turn back on or b.) change audio input to something besides HDMI ARC.  This happens literally every night when I want to use my bluetooth headphones on my optical connection...some nights I win the battle in a minute, sometimes I give up after a few minutes and end up just pulling out the eARC connection.
 

@GuitarSuperstar @Airgetlam How does one disable eARC?  (Even if I could do this it would only be temporary as I normally want it on, so I’d have to switch it back every time.)

@Weird Panda I’m not seeing the option for “Connection” on the LG settings.

If your TV is equipped with eARC, look for the eARC Support setting and switch it to OFF.

@GuitarSuperstar Found it at the bottom of the Advanced section of the sound menu.  Worked when I tried it last night.  Will see if it works in the future.  Still annoying to have to flip a separate option on and off but better than unplugging the Arc.

@GuitarSuperstar Back again.  eARC on or off apparently doesn’t make a difference.  Really would love Sonos or LG to fix this.

So I got the sequence to work for my LG C1

1. Go to Settings > All Settings > Sound > Advanced Settings and disable eARC Support
2. Next go to Settings > All Settings > General > Devices > HDMI Settings and disable SIMPLINK.

once you do this you can keep using TV Speakers or any other speakers including Sonos Arc. Make note that as soon as you select HDMI(ARC) device again, SIMPLINK will be auto enabled

Thanks, yes it works with my LG G3 and Sonos Arc also.

but it is really anoying to have to go back and disable those two settings every time I want tomlisten to Bluetooth headphones. Isn’t there any better way or fix for this? When Bluetooth is selected on the LG TV it should switch those two settings of automatically, for example…

This works, but I have problems “reversing” it when I want to use eARC + Sonos Arc again.  All the settings are done correctly (SIMPLINK does turn back on when you pick HDMI ARC wired input on LG, then you can enable eARC separately), but no sound comes out and the magic remote can’t control the Arc.  Only fix I found was to unplug/replug Arc.

How about adding an HDMI switch so you could click a button to connect/disconnect the TV and Arc? Just leave the second port unconnected.

Oof.  I mean, that might “work” but a) this should not require additional hardware, it should just function correctly and switch inputs and b) if I’m going to get up I could just disconnect/reconnect the Arc which also “works”.  I don’t know if this is Sonos’ fault or LG but they need to get their * together.

*Moderator Note: Modified in accordance with the Community Code of Conduct.*

Additionally, you can set SIMPLINK (HDMI-CEC) as a shortcut to the quick settings menu.

Hi,

I opened a ticket at LG. This is the feedback I received (translated via google from german to english):

My request:

Ladies and Gentlemen

I recently purchased an LG TV "OLED65C39LC". I use Simplink and have connected the TV to a Sonos ARC. Unfortunately, it is no longer possible to change the audio settings so that you can either use the TV's speakers or use a headset connected to the TV via Bluetooth.
 

I would like to continue to use the CEC function in conjunction with a Sonos ARC, as I normally use the Sonos ARC for audio output. In the evening, however, I would prefer to use a headset that is connected to the LG TV via Bluetooth.
 

Problem: Every time I switch to audio output “headset”, the TV resets the settings back to HDMI ARC (Sonos ARC) after 2-3 seconds. The problem has already been described by people in various forums and has existed for more than 3 years. I find it disappointing that a product like the OLED65C39LC also has this problem - even considering the very high price.
 

Deactivating the Simplink function is not a solution either! I don't understand why LG hasn't implemented the feature so that the audio settings that you set manually don't remain permanently configured.
 

I hope that LG finds a solution here and offers it to us customers.

The Feedback:

Dear Mr. *****,

Thank you very much for contacting LG Electronics Deutschland GmbH.
- Due to the CEC control, the HDMI-ARC connection is always prioritized and functions normally. I can't offer any solution other than interrupting HDMI.
 

A direct reply to this email is not possible. If you would like to contact us again, please open a new ticket using the contact form. If you have any further questions or suggestions, please feel free to contact us at any time.
 

Best regards

******