Hi all,

I’m new to Sonos Community and just bought the Arc as my first product since it had Atmos support and good reviews. I’m a general noob when it comes to these things. 
 

However I’m not sure how to get Atmos to actually run. My Sonos app shows the audio as just Dolby Digital 5.1 no matter what I do.  It never shows Atmos playing. 
I’m running an LG CX and the Sonos ARC over eArc. I have audio set to go through hdmi out(which is the Sonos ARC) and all 4 of the  HDMI’s audio outputs are set to bitstream. My setup is Sonos Arc by itself no Sub or surround speakers. 
 

Was trying to Watch Jack Ryan on Amazon Prime Video via FireTV stick 4k. 
 

The TV show supports ATMOS and so does the fire tv and the prime video app and my LG CX TV even has native Dolby Atmos decoding and supports passthrough. It even shows audio outputting as Atmos on the Prime TV show.  
 

I know that Atmos format itself is a container and streaming services use Dolby digital plus as the track. So my question is, why is my sonos app showing the audio stream as dolby digital 5.1 when the tv show says it’s outputting dolby atmos. It should atleast show Dolby digital plus if not atmos outright on the app. I’m not sure where it’s failing the chain.

The Community’s help will be greatly appreciated. Thanks so much.