So, there’s a bunch of things I would be doing to check this. First, I’d stick a pair of headphones in that jack in order to confirm that there’s actually sound coming out of it. Ah, I’ve got it backwards. You’ve got RCA jacks on the projector, going to the 3.5mm input on the PLAY:5. So it may take a little more effort, but you really should check the output from the projector to ensure it is sending a signal.



I’d check the settings on the Chromecast to ensure it is set only to stereo, since a 3.5mm jack is only stereo, and can’t handle any of the higher versions of audio.



Assuming that there is sound coming through that jack out of the projector, I would then be checking all of the line in settings on the PLAY;5, as detailed in the Line in FAQ here:



https://support.sonos.com/s/article/1080



Honestly, I would probably use another device to feed the line in for testing, like a tape player, etc.

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Thanks for the response! Double checked everything and ended up picking up an hdmi to hdmi + audio which did the trick. If anyone runs into this thread with the same problem from what I can tell this is an issue with epson projectors but you can get the $25 hdmi to hdmi + audio on amazon and this will fix the problem.

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