Is the Beam muted/silent in the controller app, or is the TV muted/silent? What device do you use to turn on the TV (some things, like Harmony remotes, set a volume when you turn on a device)

Hi, no it’s not muted in the App, and the tv hasn’t been put on silent. 

How is your Beam connected to the TV? Based on your answer, my guess is there’s a handshake on CEC that’s breaking between the TV and the Beam, assuming it’s connected via HDMI (ARC, part of CEC).

Might be worth a couple of precautionary steps. First, check to see if there’s a new firmware for your TV, and if so, install it. Second, unplug the TV and the Beam from power for 3 minutes, then plug in the TV first, give it 2 minutes to boot up, then plug the Beam back in to power, and see if that resolves the issue.

However, if it doesn’t, the next time the volume is “off” when you turn on the TV, submit a system diagnostic , and call Sonos Support to discuss it.

There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution.

When you speak directly to the phone folks, they have tools at their disposal that will allow them to give you advice specific to your Sonos system and network.

The challenge is, if the issue is the TV not sending an appropriate signal through the HDMI cable, there’s not much Sonos can do about that, and you’ll end up needing to deal with the TV’s manufacturer.