Hi @Aznman66 

Go to settings > System > Room where Beam is located > Volume Limiter. Make sure it is turned off...although the Volume Limiter should have the opposite effect of what you are experiencing and prevent the volume from being raised period. Try toggling the switch on/off a few times for good measure to make sure nothing was crossed in the Sonos software. 

Also in the same area make sure that TV Auto play is on. You might check the EQ for loudness although that shouldn’t have any effect on your issue.

Assuming all is correct with the Beam check your sound settings in the TV menu. There may be something in there that can help.

You can also try setting up the Beam again with your TV.

Which Sonos device are you using? Which TV? How are they connected?

I have the Beam and my TV is a LG OLED55B9P. Its connected through the Optical Digital Audio Out

Then I have no idea. The volume over optical is determined entirely by the Beam, which is determined entirely by the Sonos app, unless you have given Spotify Direct control over it. The TV has no way of controlling optical volume. You are not powering down the Beam itself are you? Hope not.

I don’t have Spotify or any other music streaming service. I just have my music library on my desktop.

And no,  I don’t believe I’m powering down the Sonos. When I turn off the TV, the sonos speakers still have their lights on.

Just curious, are you seeing the volume adjust in the Sonos App?… perhaps try this:

Power on the TV and then open the Sonos App and select the Beams Room from the ‘System/Rooms’ tab so it shows in the ‘now playing’ screen and then set the TV volume to say 50%.

When you then power off the TV, see if the volume slider in the Sonos App changes. If it doesn’t, then power on the TV again, to see if the volume slider changes this time.

If at any point you see the volume change, then take a Sonos diagnostic report and post the reference back here for the staff to perhaps take a look.

I suspect it won’t be the TV or Sonos device making this volume adjustment, but perhaps a device app that’s sometimes connected to the Beam, something like Spotify perhaps, but let’s see what happens with the suggested test above.

If all is okay with the test, I would perhaps switch off the options for ‘Hardware Control’ and ‘Lock Screen Controls’ that you will find in "Settings/System/App Preferences” just for a few days - to then see if that stops the issue occurring.

It’s odd, I added Sonos to my desktop to my desktop in order to access my music library and it seemed to help temporarily. If I turn the TV off and on right away, the volume returns. But if I leave the TV off for several hours, the volume defaults to zero and I have to turn it up again.

Turning the TV off and on did not move the volume slider on my phone app. I’ve turned off the Hardware Control and Lock Screen controls and will see what happens

So with the Hardware Control and Lock Screen controls turned off, I turned the TV off and back on after 30 seconds and the volume was fine.

However, when i turned the TV off (left the cable boz on) and turned it on after an hour, the volume was back to 0. I’m at a loss to explain this

So it looks like the issue is ‘perhaps’ connected to the cable TV box, but to be sure, when you get a chance, perhaps do a bit more testing by removing its HDMI cable from the TV and if the problem goes away, then you may choose to switch off the cable box HDMI-CEC control, or if that’s not possible within its settings, then you could insert a CEC-LESS adapter to see if that sorts the problem.

Example of CEC-LESS Adapter