Sonos 12.0.5 Update: Delivers Dolby Atmos to Arc with AppleTV

Shouldn’t that be the other way around DD+ Atmos works on all devices built-in and attached to say an LG C9 TV which has eARC pass-through and support that codec along with the ARC? It’s the multichannel LPCM codec that has not worked from the beginning, which is the default format of ATV. 
 

I have always understood (believed) that the compressed DD+ Atmos to always have worked on ATV 4K with ARC, or if anyone is using ATV 4HD they should always have been getting DD 5.1 - providing these codecs were set in the ATV device audio settings. It was just the multichannel LPCM (uncompressed) Atmos that was not working using Dolby MAT (which actually is sent compressed but is uncompressed by the Receiver)… at least that’s always been my understanding.

Anyhow the ‘Audio-In display in the Sonos S2 App ‘About my Sonos’ is not too helpful as it just mentions Dolby Atmos - there is no hint at whether that Atmos format is Dolby (MAT) (uncompressed) or DD+ Atmos (compressed). I suspect it’s the latter and the reason I say that, is if anyone has Apple TV4 HD (not the 4K device) and they set the ‘Change Audio’ setting to off they will likely find that Atmos movies on Netflix (example 6 Underground) is missing audio channels - you may find the dialogue spoken is not coming through. Whereas if you change the audio to ON and select either Dolby Digital 5.1 or PCM codec, then the movie audio will work with either of those codecs.. inferring that LPCM is still not supported (perhaps?). That’s the only way I can think to test it, but if anyone has any further suggestions…

Anyhow I hope that may assist to find the answer here.

@Ken_Griffiths , if your TV communicates to Apple TV 4K that it accepts multichannel LPCM, then that’s what it will output. Since LG TVs do this, Apple TV 4k outputs atmos as LPCM mat, and not DDP. 
Nothing in 12.0.5 has changed any behavior in this regard. 

Is there any release notes for 12.0.5?

It would be nice to know what they have fixed or added.

It’s not currently working here for me.👍

I think sonos staff would have stepped in and said something about this (perhaps?) - earlier comments from staff in another thread in the community, did seem to suggest it might take a while, with any testing etc. 

I’m curiously confused with all of the above.

@AjTrek1 Now you have the Atmos Logo in the Sonos App from ATV, I think what is a more important question is how much of a difference the Atmos logo adds the sound experience vs previous DD 5.1 through the Arc? Personally, so far, I have been underwhelmed with Atmos content, the best content I have heard (seen?) has been the Dolby Atmos demos downloaded from Dolby site, but I think this tricks you with the visual effects.

Does atmos as LPCM mat sounds better than DDP?

Depends on the source. If your Atmos is from any streaming service (netflix, apple tv +, etc.) then there is no difference. The streaming services send compressed Atmos (DDP), and Apple TV converts it to LPCM mat. 
 

If your source has trueHD sound (e.g. from Plex) then LPCM, being uncompressed, may sound better. 

Thanks for your reply just one question I have nvidia shield pro and I get atmos true hd using plex will it sound same if I use apple tv 4k with plex true hd source after lpcm update?

Truehd without Atmos = same on either ATV or shield, using plex

Truehd with Atmos = currently with ATV you will lose Atmos. 

Would someone be able to explain to me why the temporary fix would not be as simple as turning off eARC, and setting the TV to auto.  In reading these threads, and trying to process with my limited knowledge, it seems that with the above settings, ATV would then downgrade to DD+ and everything should work fine.  

I have tried this and still do not receive any sound.  I apologize if this has already been discussed, but I am still trying to wrap my head around how some with LG tv’s are getting sound and other are not.  I am sure it must have to do with different models and firmware, but someone much smarter than I am is going to explain it better than I am.