Sonos Beam constantly switching on LG 55 between external speaker and TV every 5 seconds

Have you got other components (cable/satellite box, games console etc)that also have HDMI CEC functionality? I had the same problem but went through turned if off in all of them (they all call it something different- it isn’t the most helpful standard..), disconnected all bar one (so I had a picture and sound) and then the Sonos set up worked.

Have slowly reconnected and so far so good! (Samsung TV, not convinced the Nintendo Switch will play nicely, and the Xbox one X loves booting up whenever the remote is touched - but that is a different prob).

Hope that helps a little.

I have an apple tv gen 4, a harmon kardon av receiver, a tivo box for antenna, a samsung blue ray, all running through HDMI Spltter system and it worked fine until I added the Beam. I had to move it all to HDMI 2 on the LG TV because the HDMI ARC input was HDMI 1. I changed all the remote macros to use HDMI 2 for the other things and the Beam is exclusively connected to the HDMI 1 ARC input.

I'll try to see if any of the other components have CEC activated. I think the blue ray player does.

I would check whether the splitter has a button for ARC as well - some do. Often a splitter helps as it takes out some of the complexity in the various signals, but obviously not in this case. Your set up does sound slightly odd to (a very amateur) me. My Beam has replaced an AV receiver which I got rid of about a year ago along with many wires and speakers. From a distance why you would have an av receiver and beam is not clear (and the HDMI splitter just adds to the mystery) - I suspect you might be able to simplify things.

Thanks. Yeah, I am ready to yank the other components but have an entire house wired with speakers in the walls. Probably just need to breakdown and disconnect them.

Good luck. Make sure the Beam works before doing anything drastic!!!

Make sure the Beam has the latest software update. I temporarily connected the Beam to my router using an ethernet cable. After the software update of everything in the house, I disconnected the ethernet and went on using WIFI. The whole thing set up in minutes using the HDMI ARC port on my Samsung TV.