2015 Vizio with no Dolby only bitstream with surround

One of those two is likely Dolby Digital. How do you have your Beam connected to the TV? What source are you playing, something over the air, or from a cable box, or from a DVD player? What do you see when you look in the Sonos Controller's settings area, under "About My Sonos"? There should be an area that lists your Beam, and in that section, it should include a line that says "Audio In" and then lists something like "Stereo" or "Dolby Digital"

The beam is connected via HDMI to the ARC on the TV.
Below is the audio in.
On the TV there is no Dolby option only bitstream.
Is there a setting on the cable box that can be changed?
---------------------------------
Beam: TV Room
Audio In: Stereo
WM:

The beam works fine but there is no sound on the 2 play 1s.

Yes, there absolutely should be audio settings on the cable box. Check with your cable provider in order to figure ou where that would be, I've been a DirecTV customer so long that I don't think I've touched a cable box in years.

You're probably getting a very tiny amount of sound out of the surrounds, when the Beam gets a simple stereo signal, it acts like a Dolby Pro Logic signal and figures out a very small amount of surround to send to them. You could turn them up in the controller really loud to hear it better, but I'd advise against it, as once we can get you with a true Dolby Digital signal from the cable box, it will likely be fine with the current settings.

I;m trying to figure out how old this Vizio is that I'm sitting in front of...but when I go to the Menu, and then select Audio, the settings I have are: TV speakers off, Surround Sound Off, Volume Leveling On, (skipping a couple) Volume Control External, Digital Audio Out Bitstream, Analog Audio Out Fixed.

But I do agree that it's most likley that the signal that your cable box is providing to the TV via HDMI is in stereo, not Dolby Digital. That's what I'd be looking at first.

Oh, the model number I happen to have is a M701d-A3, if that helps you at all. I don't see a date on it, but it was a gift from a friend, I didn't buy it myself, but it's around the same vintage as yours.

Thank you Bruce!

The Sonos tech support threw me off by stating the surround wouldn't work since there was no Dolby output on the TV. I didn't realize bitstream was sufficient and only the mode by which it is transmitted (I guess they didn't either?).

The surround does work if music comes out of the tv but not for normal dialog shows. No surround while watching the news let's say. Even the TV music isn't a very good surround quality. Volume must be high.

Thanks for the setting info. I had surround: on. That may have been an issue too.

Cable was already set for Dolby.

How much the surrounds process is completely dependent on the station and what they are transmitting. It will vary wildly from nothing to a lot

Ah! That makes sense now.