How is Google Assistant connected to your TV setup? Is your Samsung TV compatible with Google Assistant? Do you have a device like a Harmony Hub that you can control your TV with Google Assistant?

Have you installed the Google Home app and then set up your Google Assistant devices?

From Samsung:

• To change the volume, say "Okay Google, lower the volume on living room TV" or "Hey Google, volume up 10 on living room TV." You can also set the volume to a specific value, say "Hey Google, set the volume of living room TV to 50."

Hi,  thanks for the input.  I actually tried that but it doesn’t seem to work.  The volume doesn’t change nor do I see on the screen the volume adjusting like you normally would with the remote increasing or decreasing the Sonos optic connected volume.  Any thought on possible cause?

How exactly is Google Assistant connected to your TV setup? Is your Samsung TV compatible with Google Assistant? 

I have a google chrome connected to the Samsung tv.  

In your TV’s settings, is Anynet+ (CEC) turned on?

It is on

Are you 100% sure you can use Google Assistant to control the volume on your Samsung TV with just the Chromecast connected? I’ve done a little research and it seems like this isn’t possible with your setup.

Your Playbar is getting the sound from your TV via optical. There’s no way your TV can tell the Playbar to lower its volume (unlike with a Beam or Arc that will take commands from a TV by HDMI-CEC, or will even command a TV that way).

A possibility you may be to use a Google Nest Mini, that might tell the Plyabar via wifi to lower it’s volume. I do not own a Playbar, so I haven’t tried this.

Thanks for all the insight!  I’ve been using my google mini and it doesn’t work either.  
 

odd that the chrome cast can’t control the playbar being that’s it’s hooked up to the tv.  
 

which really leave a smart home setup lacking. 
 

i have a QN75Q60RAFXZA by the way.  Just before they offered google assist on Samsung tv models...

I can understand you would like this option, but I do not agree with you that it's odd the Chromecast can't control the volume on a Playbar. Normally volume on a soundbar is controlled via HDMI-CEC (impossible because the Playbar is connected to the TV via optical) or via ir (like a remote, but the Chromecast doesn’t do ir). So to me it's not odd at all -  it's just seems  impossible on the 2013 tech of the Playbar.

To explore the Nest Mini. Can you explain how you had it connected to the Playbar? I see no reason why it would not work to lower the volume on the Playbar - it does work like that on my son's Symfonisk. Could the Mini control the volume on the Playbar when it wasn’t playing TV sounds?

So I think sorted something out.  The google assist wasn’t connected on Sonos.  Now that that is done. I can control the volume BUT only the volume on chromecast controls.  Which means if the Sonos volume is at lvl. 5 and I say, “hey, google increase volume to 10” the volume on the chromecast would increase to the Max and display on the screen, “ Chromecast is at volume. Still too quite increase your TV volume”.
 

Note: at his point the volume would increase slightly.  The sound is coming from the playbar which means chromecast is using the playbar as expected being that it’s on optics but seems to be a secondary volume control vs the main control volume which at the moment the in my example the Sonos volume is still set at lvl. 5 and hasn’t changed.   
 

the chromecast is plugged into the TV’s HDMI

What if you would choose the Playbar as preferred player for the mini?

Hi @Kaster 

Welcome to the Sonos Community!

You can see commands that work with Google Assistant and Sonos on our Control Sonos with the Google Assistant page.

Note that you will need to address the Playbar’s room name and not the TV’s. If they are similar, you may want to rename one. If both are called Living Room, for example, I recommend you change the room name of the Playbar to “Playbar”.

Then, the command “Hey Google, turn it up in Playbar” should address the speaker rather than the TV, which is what you want. You can probably get away with saying “on” instead on “in”.

You could also call the TV “TV” instead of “Living Room TV”, and leave the Playbar named “Living Room”.

To rename a room in the Sonos app, select Settings » System » oroom name] »  room name] and type the new name.