Nothing will break if that’s what you mean. I’m surprised you still have sound from the Arc though. Does your Arc still get all sound options (5.1, Atmos etc.)?

Wouldn’t turning CEC off on the ATV or putting a CEC killer between ATV and TV have been a better option? Then you’d still have volume control, which is indeed a CEC function.

That’s what I thought but Isn’t hdmi control and hdmi Arc/eARC a separate thing?

I think ARC only tv would require HDMI CEC to be enabled to function, but with eARC, hdmi control is not a requirement, someone else may be able to confirm this.

I thought about a cec killer and may do that still.

My only experience is with HDMI-ARC, so eARC could indeed be functional without CEC.

Audio on HDMI and audio on HDMI-ARC/eARC use two separate sets of pins on the HDMI connector. CEC uses yet another pin. The SONOS ARC uses only the HDMI-ARC/eARC audio channel, ignoring the regular HDMI audio. And, of course, ARC uses the CEC pin.

Some TV’s will limit audio routing and formats if CEC is disabled. In this case a CEC blocker is more effective because CEC can still be enabled, but there is no CEC data that can be mishandled.

In general I find that CEC is a “cross your fingers and hope it works” deal. There are no ridged standards specifying exactly what should happen as CEC data is sent out or received. When it works, the idea is that when a disc is dropped into a DVD player, all of the other units will power up and correct inputs will be selected. My favorite little glitch is the 3:00am cable box update that ends with turning the cable box ON. At that time the other system units assume that the user wants to watch cable TV and they’ll power up too. I make a very deliberate effort to minimize Volume when I shut down for the day.

Thanks CEC disabled on my lg cx is working well with the Sonos so far so I will continue like this for now.