If you mean you’re using the Sonos optical-HDMI dongle there’s no way the Arc could ‘take over’. The TV wouldn’t know the Arc was there at all. Optical is unidirectional.

No, just tried setting the TV to optical out to see if it would stop the Arc forcing connection back to itself over the eARC connection. Even for optical out (without anything attached to the optical port), the Arc forces connection back to itself after 2-3 seconds 

What happens if you turn off the ARC/eARC function in the TV’s settings? Does it still revert?

And is that actually a different setting than turning on the optical output, or are they essentially one and the same? 

Yep all settings that change ARC/eARC revert including changing to Optical. For instance, when setting the HDMI-CEC to disable, two or three seconds later it forces itself back on (with a notification of “Simplink On”. When disabling eARC from memory its the same behaviour.

Ideally I dont want to be disabling eARC for Dolby Atmos for when watching movies etc - just want the Sonos to stop forcing the connection back to itself, or better yet a way to disable/turn off the Arc in software without physically removing the power or HDMI cable...

Hi

These instructions (that work  ) are for a LG Model 55NANO90UNA.

LG menus change slightly in appearance between models (I have 3 LG’s) but for the most part can be easily navigated. I use my Bluetooth Headphones in the bedroom for obvious reasons at night when I can’t sleep and don’t want to move to my media room.

1. First register your Bluetooth (BT) Headphones as a Device on your LG (Step 2)
2. Go to All Settings > Sound > Sound Out > BT > Device List (3 dots/lines) 
3. Place BT Headphones in Pairing Mode > Select Search > Register BT Headphones as a Device
4. Go to Connections > Device Connections > Turn Off SimpLink (CEC) *
5. Go to Sound > Sound Out > HDMI > Bluetooth
6. Enjoy your BT Headphones

 * SimpLink (CEC) will auto-turn on when you switch back to HDMI in Sound Menu

Note: When viewing content via AppleTV 4K (physical box) with AirPods Pro or AirPods Max the above steps aren’t required. Just switch to HDMI input for the AppleTV 4K and connect AirPods Pro or AirPods Max in Apple Menu. After the first connection subsequent connections are automatic when in range.

FWIW, it’s not Sonos that is ‘forcing’ the change, it’s the way ARC (part of CEC) is written. All Sonos does is publish the fact that it’s a speaker and what formats it can deal with to the hub, which is the TV set. It has no “control” there. All of that is handled by the circuitry in the TV set. 

Many thanks, i’ll give it a crack soon but from when I tried this, at Step 4, the TV just keeps switching back the CEC back on (Simplink On) even when switched off. This could be an issue with the way the G1 (OLED65G1PUA) is handling the eARC connection...

Interesting, I have raised a case with LG and they’ve sent my feedback to their Software Bug/Firmware team so waiting on feedback and troubleshooting with their engineers. Fingers crossed its something that can be solved. 

I have the identical issue. I'm following with interest. Thanks!  

Here are my experiences with OLED65CXPUA and ARC. I too have the same intermittent issue with Bluetooth headphones disconnecting after a few seconds and reverting back to eARC (ARC). I can resolve the issue by unplugging the TV for about a minute or by turning off SIMPLINK as previously described. I didn’t have to re-pair my headphones for this to work. As indicated, SIMPLINK will turn itself back on when the TV is powered off/on.

As a side note, I found that if I turned the TV off while connected to my headphones, it would revert back to eARC/ARC on the next TV start-up. If you disconnect the headphones while the TV is on, it will revert to internal speakers and you have to manually switch back to eARC/ARC.

this is not a tv issue!  this is 100% a sonos issue with HDMI eArc connectivity.  sonos needs to take accountability with this issue and fix the problem.  i install tvs and sonos for a living and have this problem with multiple brands of tvs with any sonos plugged into tvs with hdmi eARc/ARc.  the only work around that i have found that works is to use the optic adaptor.  you then need to ensure the sound on the soundbar is turned down to down low so you can use the bluetooth headphones with this.  obviously not an ideal work around as it doesn’t allow dolby atmos.  COME ON SONOS!!!!!!!YOU ARE BETTER THAN THIS!!!!FIX THIS PROBLEM!!!!!!!!!

No, it’s not a TV issue. Nor is it a Sonos issue. If you’re a TV installer, you should take a few minutes to familiarize yourself with the design specifications for CEC, and ask those who set up those specifications why they only permit a single sound ‘sink’ device at a time. Both the TV manufacturers and Sonos have designed their systems to that specification. 

FWIW, I have a LG CX 55” in the bedroom that will allow for SIMPLINK to be switched off and compliant with the SONOS BEAM GEN 2 and bose bt soundwear.
HOWEVER, the LG C1 65” in the living room is more proudy and refuses to give up control of the hdmi arc, and simplink will turn back on with seconds. So whatever change LG made between the CX - C1 is conflicting. Ive been in touch with LG, but tech level 1? dont seem to understand the problem and have referred me up the chain of command. Im not really sure if this is a SONOS or LG issue, but one solution that Im contemplating is buying a Nvidia Shield 2019 for the living room after using the 2019 Pro on the CX. (The cx is in my bedroom whereas the C1 is a living room thing). Im not entirely impressed with the WebOS UI anyways and I know google tv (shield) would be a better solution for both watching content, dolby atmo hdr vision upscaling etc, and the BT Headphone issue. 

In other words im willing to concede defeat.

I have a Samsung QLED with the same ARC CEC issue: The Sonos takes over from the Bluetooth headphones within 2-3 seconds.  The lame workaround I use is to unplug the HDMI cable from the  back of the Sonos bar and then pair the BT headphones. Works fine, but not the way it should.

I have the same problem using Sonos Arc (HDMI), LG OLED C1 TV, and Bose Q45 headphones. The only way for the headphone pairing to stick is to unplug the Arc and this is not the optimal solution. 

Did this ever get figured out? Just bought a G1 and ran into this and now am frustrated.

This is a common concern with any device, including Sonos, that uses CEC. CEC is a standard that ‘allows’ a single speaker ‘sink’. You’d have exactly the same issue with any other manufacturer’s speakers, if they use CEC. See https://en.wikipedia.org/wiki/Consumer_Electronics_Control for more information. 

As has been discussed in many threads, you may want to turn off CEC on your TV, which is the controlling hub for that system. Most people find that doing that still allows the use of the Sonos, and leaves the optical port active that they connect their headphones to. 

Just got an Arc for my LG G1 and can confirm this is still an issue.  Definitely a Sonos issue as I also tried the latest Samsung Q990 and LG sound bars and the Samsung and LG bars both allowed headphone use with no issues.  Same TV, same headphones, different sound bars, all using CEC but only Sonos had an issue with headphones.  

This is still an issue. 

The same issue on LG G2+Sonos Arc.  Disabling SympLink(HDMI-CEC) on TV auto enable it back in few seconds with connected Sonos arc by HDMI eArc. Tried with TV+PS5 only, disabled SympLink(HDMI-CEC) , no auto enabling for SympLink(HDMI-CEC) as expected. Looks like either Sonos  or LG firmware handle HDMI-CEC wrongly.

It's few years for the ISSUE, no explanation neither from Sonos, neither from LG - SHAME! 

Sonos sucks.  No reason it couldn’t write a software fix to work around this problem.  Sonos simply refuses to do so.  How easy to blame CEC, etc. Just take responsibility, Sonos, and offer a solution.

I have the same issue

The only way it worked on my LG TV was by turning OFF “SIMPLINK”, then connecting to BT or any other output.

See post: (1) Cannot use SONOS ARC and bluetooth headphones? : sonos (reddit.com)

Another suggestion (on the same post) that works as well is to connect the ARC to a smart plug so that you can turn the ARC ON or OFF as you please.

That used to work on older LG:s. It worked like that on my 5 year old TV, but it doesn’t on my C1. Now I have to unplug the Sonos Arc.

This is a nonsensical comment.  If you are plugging into the TV using optical, then you are plugging into the TV through optical, _not_ HDMI.  It works perfectly for me.