Sonos ARC + LG 75UK6570PUB Inconsistent Atmos

Hi @BASONOS, sorry for the late response, thank you for reaching out and welcome to the community.

Since you’re using the LG WebOS apps, we should consider the streaming service.

Netflix has a handful of selected has Dolby Atmos. If you’re not getting Dolby Atmos for Netflix, I would recommend getting in touch with LG is the built-in Netflix app has a firmware update.

You can also check Netflix for the selected titles with Dolby Atmos.

For the ATV 4k, Dolby Atmos is supported  but it will depend on the content if it supports Atmos.

You can refer to this article for more details. 

I have an LG OLED B8.  Not familiar with your model, but sounds like it is Dolby Atmos capable with HDMI ARC connection.  I am getting DD+ from ATV4K.  When I first got my Sonos arc I wasn’t getting DD+ and had never tried my LG native apps.  I discovered my Tv was out of date on the firmware.  That allowed me to get ATV4K DD+.

but heads up in advance… using Netflix through ATV4K, as you mentioned I get a better picture, but I also get an uncorrectable lip sync which is very annoying.  I should note the lip sync is only when receiving the Dolby Atmos signal. It is fine for 5.1. The lip sync almost (if not all) all LG owners have.
 

so now I am using the LG native Netflix.  I get DD+, without lip sync issues and have had to adjust some picture settings (gamma and brightness) to bring the picture to a bit of a better quality.

Thanks for your reply. Do you have eARC? 

I’ve upgraded to the latest firmware so I should be good there.

I had never used the native apps before the ARC. I’m getting DD not DD+ from the ATV4K but I’m getting Dolby Vision.

On the native Netflix app I can get DD+ no Atmos no Dolby Vision. 
 

I’m only getting Atmos from Disney+ and Amazon so I know it’s capable of working. I just can’t figure out how to make it happen with any other sources. 

I did notice a little lip sync lag with Atmos using the Amazon WebOS app. I set the TV dialog sync to +1 which seemed to take care of the problem. 
 

Do you mind sharing your ATV4K + LG settings? Did you chance any default settings to get Atmos to work through the ATV4K??

Thanks again!

Thanks for your reply.

All firmware is up to date. LG tv, ATV4K, and apps.

I’ve checked with content that I’m sure has Atmos like “The Irishman” and it streams DD 5.1 from the ATV4K.

Thanks for the link to the article. I’ve already read through that several times and I’m still lost...

No eARC here,I have an ARC connection.  I only get DD+.  Don’t forget that DD+ is Dolby Atmos, it is lossy version, not trueHD.

when you are receiving DD+ you should see this Dolby Atmos symbol on your Sonos app.  Also below is my settings 

Hi @BASONOS, since other services are working with Dolby Atmos. 

I would recommend getting in touch with either LG or Netflix for support.

Even though, TV’s firmware is up to date there might be some updates with the built-in apps or upcoming updates.

It’s similar to a phone's Operating System, there are updates for the OS and there are updates for the apps.

If you have other concerns, just reach out.