Not all apps support 5.1 audio.

Keep the Change Format setting set to ON and Audio Format set to Dolby Digital.

Which apps are you currently getting Dolby Digital 5.1 audio? Which apps are you just getting stereo PCM?

Huh, so forcing the setting this time now shows it playing 5.1 (via the Sonos app) when watching Netflix, Disney+ and Prime Video…

But an episode of Big Mouth on Netflix advertised as 5.1 on the episode guide, showing as 5.1 in Sonos but nothing coming out of the surrounds :-(

Am I being daft or is that wrong?

If the Sonos app is displaying Dolby Digital 5.1, you are getting 5.1 audio.

Are you sure the surround speakers have been properly bonded to the Beam? Do you hear audio from the surround speakers from other shows/films in 5.1 on Netflix? It may just be that you are watching a front heavy scene with little to no surround audio. Forward to a scene with more action or the score playing in the background.

To echo some of what @GuitarSuperstar said, just because a show is “broadcast” in 5.1 doesn’t mean it actually *is* in 5.1.

Frequently, while living in Texas, the local CBS station would broadcast the Dallas Cowboys pregames on a 5.1 carrier, but the source itself was only stereo, and there was nothing actually coming from the center speaker, or the surrounds (or Sub, for that matter), due to the fact that the signal they had encoded in to 5.1 was just a stereo signal.

It is not overwhelming frequent, mind you, but as he states, it’s not impossible. That’s why I frequently suggest a program with significant usage of surround sound information, such as the Star Wars movies, or Saving Private Ryan’s starting sequence when they’re storming the beach. It’s just too common for standard TV to be just stereo encoded in a 5.1 signal. Most talking heads (news, etc) are generally recorded in stereo, and broadcast in 5.1, for instance.