Connecting Google Chromecast to Projector and Sonos Beam

  • 23 April 2022
  • 2 replies

Hi All,

Really could do with your help, have given up multiple times, but want to give it one last try before i ditch the Beam (1st gen).

I’ve got an Optoma P2 Projector, which has HDMI and Optical Output. The P2 support Dolby Digital 2.0 (HDMI ARC and Optical Output support Dolby Digital and Dolby Digital Plus pass through).

We stream from the Google Chromecast to the P2 projector, but have never (for 2 years) been able to get audio to the Sonos Beam and have had to settle for the projector speakers.

I’ve tried an audio extractor (Input = Chrome Cast HDMI, Output = HDMI video to P2 and Optical to Beam via the supplied HDMI to Optical cable) but haven’t had any luck.

Have also tried routing the audio from the P2 project direct into the Beam, I’ve noticed the optical output on both the extractor and the P2 have the red light, but am perplexed why I am not getting any sound.

Is there something within the Projector, the Speakers or Chromecast I’ve missed?


This topic has been closed for further comments. You can use the search bar to find a similar topic, or create a new one by clicking Create Topic at the top of the page.

2 replies

Thanks Bruce.

I took your advice and plugged the chromecast direct into the Beam and no audio came out. I suspect the chromecast doesnt output the right format.

Will give the Apple Tv (2nd gen) a try and see if the optical and hdmi direct from the Apple Tv to the P2 Projector and Beam Soundbar works.

The P2 only permits Bitrate and PCM config, no other sound settings. I’ve tried with both the ARC and non-ARC HDMI port.

The Google Chromecast with Google Tv support Dolby Digital, Dolby Digital Plus, and Dolby Atmos.


It would be a help if you were to provide links to the manuals for these various devices. I’m struggling to look them all up in order to understand their capabilities. 

The Optoma cinemaX P2 does, according to the product page, have ARC. I’d be doing any testing for now by connecting the Sonos provided HDMI cable between that ARC port and the Beam. If your using another cable, it’s possible that it’s an older HDMI version that doesn’t support ARC. 

My guess, at this moment, is the signal being passed via Chromecast to the projector is not in a format that the Sonos can read, so something other than Dolby Digital (likely DTS, but it’s odd to assume that everything being sent is in that format). There might be audio settings that need to be fiddled with, in both the projector, and the signal sending device to make sure what type of audio signal is being sent. I’d be really tempted to temporarily connect another source to one of the other HDMI ports on the projector to really see if it’s a Chromecast issue, like a simple DVD player.

If both the projector and the audio extractor device have red lights when on, that’s a pretty good indicator that their working, if they’re not sending a signal to the Sonos adapter that plugs in to the Beam, it is a good secondary indicator that the audio format being sent to the projector is not able to be passed properly, which again suggests something higher than Dolby Digital, which is at the bandwidth limit for optical transmission. 

Can you just play music on the Beam, by using the Sonos controller, without dealing with the video?

Have you tried contacting Sonos Support directly?