Hello. Try testing different sound settings on the TV.  E.g., Sound = pass through or Sound = Auto or something similar. If the content is truly Dolby Atmos, changing sound settings on the TV might help.  

What title movie are you playing on Netflix that is Dolby Atmos? I will check it on my system that is set up for streaming Dolby Atmos which I can confirm on my Sonos App. 

I have tried Auto and PCM but Passthrough is greyed out. Movie is 6 Underground.

Oh ! Thank you for the reminder. I have been waiting for that movie

I have my LG TV set to Digital Sound Out “pass-through” and can confirm Dolby Atmos streaming via Netflix App on my Apple TV 4K 2021 to the ARC. 

I also tested with the Netflix App on my LG CX TV--confirmed Dolby Atmos streaming to the ARC for that movie too. 

Is there some other setting on your TV that might be causing your pass-through option to be greyed-out? 

I found this with regards to Samsung TV: Based upon what I read here...you may need an external HDMI device like an Apple TV or some other device to be able to access pass-through. 

https://us.community.samsung.com/t5/QLED-and-The-Frame/Sound-passthrough-option-greyed-out-while-using-tv-apps/td-p/2163302

“That's how it is supposed to work. Passthrough is only when the source is an external HDMI device, the TV will passthrough the audio from that device to your soundbar or AV receiver. When using the apps, it's sending the sound directly from your TV, it's not acting as a "middleman". I get surround sound in the Netflix app with the Auto option, passthrough is greyed out because there is no HDMI source.”

@KishanPatel0804 I believe the Pass-Through setting is only supported when the source is from an external media device connected via HDMI. So if it’s greyed out, set Digital Output Audio Format to AUTO. Also set Dolby Atmos Compatibility to ON.

Do you have a premium Netflix account? Are you playing the original language audio track?

Log in to your Netflix account on the Netflix website on a web browser, and go to Account > Profile & Parental Controls > your profile > Playback settings. Set “Data usage per screen” to HIGH.

Thanks for the replies.

Would make sense passthrough is only for external devices as I have checked now and it is not greyed out on my virgin tv box. With passthrough on, and in the Netflix app on virgin box I am now getting Dolby Digital Plus 5.1 rather than Dolby Multichannel PCM 5.1. 

As @GuitarSuperstar said maybe my Netflix account doesn’t have the privileges for Dolby Atmos signal as it came free included in my virgin media package so it is the standard netflix package. I have tried changing netflix settings to high, to no avail. 

Dolby Atmos setting in Samsung settings is also turned on. 

Will have another play around with settings now

Have tried a Dolby atmos test video off the YouTube on app on virgin tv box, trying each of the Samsung  sound settings and they all play the video in Stereo PCM

A premium Netflix subscription is required to play Dolby Atmos audio. On the Netflix website under your Account, it will say what plan you are on under Plan Details.

Don’t test Dolby Atmos videos on YouTube. YouTube doesn’t support Dolby Atmos audio, and 99% of YouTube videos are only in stereo. There are some YouTube videos available in Dolby Digital Plus 5.1, but they are extremely rare.

Just checked and sorry you are correct,i have standard package which doesn’t include Atmos, just me being dumb.

Any other ideas how I can try testing dolby atmos signal?

Guessed that might have been the case for Youtube.

Go here: https://thedigitaltheater.com/dolby-trailers/

For the best compatibility, you want to download anything that says “Dolby Digital Plus 5.1 ATMOS”,  Put them on a thumb drive and play them from your TV’s USB port. 

And last time I checked, all YouTube content was in stereo, and not Dolby Atmos.  Or Dolby Digital, for that matter. 

If you have Prime Video, test the film The Tomorrow War or the Jack Ryan series.

You might be able to download these Dolby Atmos files onto a USB flash drive and plug it into your TV to play the files:

https://download.dolby.com/us/en/test-tones/dolby-test-tones_5_1_2.mp4

http://media.developer.dolby.com/Atmos/MP4/Universe_Fury2.mp4

http://media.developer.dolby.com/Atmos/MP4/shattered-3Mb.mp4

You can start a Amazon Music Unlimited free trial and play Dolby Atmos music directly from the Sonos app. Here are some good songs/albums to test:

“Rocket Man” - Elton John

“BOOM” -  Sevenn and Tiësto

“Riders on the Storm” - The Doors

Don’t Know Why (album) - Norah Jones

Automatic for the People 25th Anniversary Edition (album) - R.E.M.

The Future Bites (album) - Steven Wilson

John Williams in Vienna (album)

3-D The Catalogue (album) - Kraftwerk

There are some videos on YouTube available in 5.1 now. The 5.1 audio doesn’t sound great, but it’s good to see that YouTube is making progress with multichannel content.

I’m not sure 5.1 on YouTube is supported on all devices though. It works on my Roku Ultra and Apple TV 4K. NOTE: You may have to change the audio settings on the video:

Both of these videos play as “Dolby Digital Plus 5.1” for me.

Hi Everyone,  I’ve connected Sonos Arc to Samsung QN90C Neo Mini QLED eARC HDMI port.

In TV, Settings > Sound > Pass Through is greyed out. Dolby Atmos is also greyed out. I’ve gone through all the above comments and tried all the solutions. Still these settings are greyed out. What could be the reason?

I’ve played Jack Ryan from Amazon Prime Video which is in dolby atmos but it’s showing as “Dolby Multichannel PCM 5.1” in sonos app

All the other videos played in TV(Netflix/YT/Prime Video) are shown as “Stereo PCM"

I think i am using HDMI cable is HDMI 2.0. Is that the issue here? Do I need HDMI 2.1 cable?

For sound no cable above 1.4 spec is needed. If you are using the apps on your TV it is strange that you would get PCM because as far as I know all apps send out Dolby Digital. So the question arises what t(e sound settings on your TV currently are.

You need to be playing a 5.1 or Atmos source before you are able to change the TV setting to Pass Through.

Also, most YouTube videos are only available in stereo. And you need the “ad-free” paid subscription to Prime Video to get Atmos audio.