I am documenting a problem with setting up my Beam, to which I devoted half a day of my time and found two semi-satisfactory solutions.
Problem: When I attempt to connect my Beam to my Sony Bravia TV via the HDMI-ARC, the Sonos app says there is “interference” and that I should disconnect other home theater devices. The only other device I am connected to is my Arris cable box (Suddenlink) via HDMI so I unplug that, and the Beam connects to my TV. Then I plug the cable box back in. At that point, the Beam works, and volume can be controlled from the Sony remote. However, within a few minutes (or sooner than that, if I turn the TV off and back on) the TV starts kicking me out of the Beam and back to TV audio. Then the Beam needs to be set up again. Very frustrating.
Solution One (Sonos tech support): connect Beam via optical audio adapter instead of HDMI-ARC. This works and is stable… but the TV volume can only be controlled via the Sonos app, not via the TV remote. The TV happens to be in our guest house, and telling guests that they need the Sonos app in order to change the volume of the TV is not an attractive option.
Solution Two (web research, including one posting in the Sonos community, as endorsed by Sony tech support): connect TV to HDMI via an adapter that disables HDMI-CEC. The adapter I used was “Lindy HDMI CEC Less Adapter, Female to Male” purchased on Amazon; I’ve also read of people doing the same thing by disabling specific pins responsible for HDMI-CEC in the HDMI plug. The Beam works, and the Sony remote controls the Beam audio volume. However, the cable box won’t turn off via the Sony remote (it will turn ON). You need to use the cable remote to turn off the cable box. Not real convenient, but better than the first option.
Disclaimer: Maybe I’m missing some elegant and fully functional solution, or failed to understand what Sonos or Sony told me, but as a not-particularly-technical person, this is where I ended up.
Anyway I hope this is of help to someone.