Hi.  I have seen it stated on other threads that the Beam takes an HDMI-ARC feed, which is not the same as HDMI.  I have no personal expertise on that, but it might explain your problem.

Does your switch have a digital optical out connection?  If so then you might try that with the optical to HDMI-ARC converter supplied with the Beam.

(I am assuming that you have an HDMI switch / audio extractor rather than an HDMI splitter.)

Is the PS4 your only source?

I’d concur with John B. Unless your splitter has the ability to create an HDMI-ARC signal, something genarrly reserved for the electronics in the display device, and not part of the source signal, you won’t get anything from the HDMI signal to the Beam. 

In your case, I’d give stripping consideration to an HDMI switch which also provides an optical output for the audio stream, and use that to connect to the adapter that came with the Beam, which will then convert the signal to HDMI-ARC. A relatively inexpensive solution.

Why would you need to split audio to the Beam and video to the TV? Or does your TV not have HDMI-ARC?

He has a projector. Most projectors do not have the electronics in them to support HDMI-ARC.

Thank you John B and Airgetlam!  I really appreciate your time and input here. This was faster and more comprehensive than the Sonos help. I’ve ordered an HDMI splitter with an optical output. I’ll be sure to let ya know if it works out!

Yes, please do.

Hi bmoore002

Did you get this to work in the end?

I’ve also got a PS4 + projector + Beam and used an HDMI audio extractor to send the audio signal to the Beam via optical using the supplied adaptor but can only get Stereo, not 5.1. so wanted to know if you’re able to get 5.1 with your setup?

Is your PS4 set to DolbyDigital?

Yes it is but the Sonos app still says I’m getting ‘Stereo 2.0’ 

the audio extractor I’m using is here:

Neoteck HDMI Audio Extractor HDMI... https://www.amazon.co.uk/dp/B01J9ZVPZK?ref=ppx_pop_mob_ap_share