Were you able to get Dolby Atmos audio from the Chromecast from Disney+, Netflix, Apple TV+, and TIDAL when you were using the Arcana with the Panasonic TV? If so, you should still be able to get the same audio using the projector. You might try performing a factory reset of the Arcana.

That’s right - I was able to get Dolby Atmos audio from the Chromecast from Disney+, Netflix, Apple TV+, and TIDAL when using the Arcana with the Panasonic TV. I have tried a factory reset to default settings and even updated the firmware to 0.86. I am just hesitant about buying a new streamer or TV as they may not solve the problem. 

Not sure if this will do anything, but have you tried setting the TV ARC Routing setting to OFF on the Arcana under the Audio OLED menu? You may have to unplug the projector and Arcana from power for about 30 seconds after you adjust this setting.

Thank you for the suggestion. I will give it a try and give you an update. I think I have tried the setting but may not have systematically unplugged and powered off the devices.

Anytime you change a setting on the Arcana, you need to power cycle the Arcana and projector. If you didn’t do this after each time you adjusted the Scaler setting or when you performed the factory reset, you might want to try those settings again followed by a power cycle.

Noted. I have systematically tried the following combination of settings however they all yielded stereo pcm on Prime (Jack Ryan) and Apple TV+ (Swan Song):

1. TV ARC routing off, Scaling Auto, Audio eARC only
2. TV ARC routing on, Scaling 1080p 12b HDR, Audio eARC only
3. TV ARC routing on, Scaling 1080p 12b SD, Audio eARC only
4. TV ARC routing off, Scaling 1080p 12b HDR, Audio eARC only
5. TV ARC routing off, Scaling 1080p 12b SD, Audio eARC only
6. TV ARC routing off, Scaling 1080p 12b HDR, Audio eARC+Display
7. TV ARC routing off, Scaling 1080p 12b SD, Audio eARC+Display

I was wondering whether it could be anything to do with my projector HDMI not having ARC or that there is no mention of Dolby Digital in the manual (https://www.viewsonicglobal.com/public/products_download/user_guide/Projector/PA503XE/PA5%20series_UG_ENG.pdf?pass). The native resolution is 1024x768 but it supports Full HD (1920x1080). Because when going through the Sonos App TV setup I would sometimes see Audio Output not connected although I am able to get audio through the speakers.

This is hard to understand.  You are bypassing the projector for audio as you were for the TV, so it should not matter at all what the audio possibilities of the projector are.  This makes me wonder if you really are bypassing the projector. although I can’t think how.  You definitely have video sources going to the Arcana input, Arcana eARC out to the Arc, and Arcana HDMI out to the projector?

I cannot offer much logic for the following two suggestions, but they may just yield some useful clues:

1. Disconnect the HDMI to the projector, so you just have audio.  Or even power off the projector completely
2. Turn off CEC

No worries. I gave those two suggestions a try but the issue still remains. 

Can you confirm what input(s) you have connected to the Arcana?  Is a switch involved?

The Google Chromecast with Google TV is directly connected to the Arcana with no switch involved 

It is possible that you have already seen this thread

and I know you have experimented with some of the scaling settings. But it appears that the Chromecast device and Arcana don't get on very well, at least not with a projector involved. You may be able to cure this by more experimentation with the scalar settings. 

Even if you succeed then that may not work for all apps

I think you may be better off getting a different streaming device such as a Fire Stick 4K.

Thanks for sharing the post and suggestion. It really seems to be the case that it is the combination of a projector and the Chromecast that is giving rise to this problem.

Thought that I might also share that after doing a full factory reset of all devices, including the Chromecast, I encountered the error shown in the picture when connecting the Arcana to the projector. I did a full power cycle of all devices and ended up getting Atmos. But it was short lived because after turning off the devices for the night I am not getting any sound.

I guess it is safer to just get a new TV or streaming device. Much appreciate all for your help and time :)

Occasionally my ARCANA gets its nickers tied in a knot and nothing makes sense. A factory reset of ARCANA while nothing is connected fixes this.

Hi,

Same problems as other but just want your opinion. 
 

Have a Panasonic Plasma TV with Arc output. A Google Chromecast Gen 3 and a Sonos Beam Gen 2. 
I use the chromecast to cast mainly Netflix from my IPhone but only get PCM stereo in the Sonos. I have read several threads but are wondering if the Arcana Will help to get atmos with the same setup?

Or if i could do anything else to make it work?

I’m using a cheap LG that does not support eARC, with ARCANA and Chromcast E9L29Y. Atmos is fine on ARC.

Bought the Arcana and the new GCTV but waiting for both should arrive next week. So fingers crossed