Hi

Review page 24 of the Sony UBP X800 manual for BD audio settings. 
 

Note: Page 24 is how it appeared in the online PDF version. The page in the actual manual may differ slightly.

You need a TV with HDMI eARC to get Dolby TrueHD/Dolby Atmos audio from Blu-ray or UHD discs. I’m pretty sure your TV only has HDMI ARC.

Thank you very much for your replies!

AjTrek1, I looked at the Sony manual and tried tweaking some settings but I still can’t get Dolby TrueHD through my Blu-ray player.

GuitarSuperstar, you are absolutely right that my television doesn’t have HDMI eARC, so that cancels out Dolby Atmos. The strange thing is the Sonos app tells me my Apple TV films are playing in Dolby Atmos. I did think that Dolby TrueHD would be able to play via my player though, but I suppose not.  

Thank you again.

No, it doesn’t rule out Dolby Atmos. There are two ‘types’ of Dolby Atmos, compressed and uncompressed. Uncompressed requires eARC, and carries more channels (which are actually ignored by Sonos), amongst other things, and compressed, which can be encoded in a Dolby Digital Plus signal, which is ‘small’ enough in bandwidth to be carried across HDMI ARC.

If you’re able to feed your TV a Dolby Digital Plus signal, rather than a Dolby TrueHD signal, it is entirely possible that the TV would be able to pass that Atmos signal encoded in Dolby Digital Plus to your Sonos Beam. 

When you say “Apple TV” are you referring to the Apple TV media device or the Apple TV+ app?

Dolby Atmos audio is carried through three different audio codecs: Dolby TrueHD, Dolby Digital Plus, and Dolby MAT.

Dolby TrueHD and Dolby MAT Atmos requires HDMI eARC because they are higher resolution audio codecs. You see TrueHD mainly with Blu-rays and Dolby MAT on the Apple TV 4K and latest Xbox consoles.

Dolby Digital Plus Atmos is lower resolution and only requires HDMI ARC. DD+ is primarily used with streaming apps. You are getting Dolby Digital Plus Atmos from the Apple TV+ app.

FYI… Prime Video has very limited Atmos content. Test the Jack Ryan series, The Tomorrow War, Carnival Row, or Suspiria.

Thank you Airgetlam and GuitarSuperstar for your knowledgable answers. I must be getting Dolby Digital Plus Atmos via the AppleTV app. I’ll make sure the next television I buy has HDMI eARC so I can listen to Dolby TrueHD and Dolby Atmos via Blu-ray. Regardless, the bar sounds brilliant, so I’m happy with it for now.