apple tv 4k + sonos arc + samsung serif

No Just Auto without atmos :(

?

One thing you didn’t answer about the Apple TV settings. I said: 

“In Audio Format, go to Change Format and select Off.

This should then give you the option Immersive Audio, where you can set Dolby Atmos to On.”

Were you actually presented with the option set Dolby Atmos to ‘On’?

Its just auto there is no immersive audio it’s not showing 

I just found the answer on Apple’s site.

For Dolby Atmos, your Apple TV 4K needs to be plugged into a TV with an HDMI eARC port - unfortunately an HDMI ARC port will not cope with the bandwidth required for the sort of Dolby Atmos used by Apple TV. 

So what you are getting from your Chromecast must be a lower bandwidth Dolby Atmos, which your HDMI ARC port can cope with. 

Sorry it’s not better news but after all that, you can’t have Dolby Atmos on the 2019 Serif...

Ok thanks for helping 

Do you have any other solution like for example a receiver or dongle or anything else 

If you want to use something other than the Apple TV for Atmos, as you only have HDMI-ARC, you’ll need a player/dongle that uses Dolby Digital Plus for its Dolby Atmos, according to this article.

https://support.sonos.com/en-gb/article/listen-to-dolby-atmos-on-sonos

I think the latest Fire Sticks use Dolby TrueHD for its Atmos, so that isn’t going to work either. Not sure about the Roku stick.

But you said Chromecast and your TV’s built-in apps give you Atmos - so why not just use those? Unless I am misunderstanding your question. 

Yup that’s right I can use the built in apps or chrome cast  but I prefer using apple tv because of Apple ecosystem 

I know what you mean. I wouldn’t want to not be using my Apple TV for overall experience. At some point you’d need to get a new TV unfortunately to get Dolby Atmos from it on your Arc…