Are the Ones connected to the Beam as surrounds? Are you watching 5.1 content or stereo content? With some stereo content, the audio will not be very noticeable from the surrounds.

You can also adjust the surround levels for TV audio in the Sonos app if you want them to play louder.

FYI…

What should be playing out of those channels?

Audio that is already mixed into 5.1 channels will play from each channel as intended. Most audio comes out of the front channels, especially dialogue and the audio for what action is happening on screen.

If the source you’re playing isn’t in 5.1 already, your Sonos home theater speakers will perform an audio up-mix of the stereo signal to create a simulated surround sound. This means you’ll still hear most audio out of the front channels, but the rear left and right speakers will play what we determine to be ambient audio. This is most obvious in action scenes and with movies that have intense soundtracks.