You cannot get Dolby Atmos audio with the Arc connected to the TV’s optical port. You need to connect the Arc directly to your TV’s HDMI ARC port.

And because your TV is a little bit older, there is a good chance that even with the Arc connected to your TV’s HDMI ARC port, your TV will still not be able to pass through Dolby Atmos audio via Dolby Digital Plus from the Netflix app.

When the Arc is playing Dolby Atmos audio, the Sonos app will clearly say “Dolby Atmos” after “Audio In:”.

Yep, that’s my thoughts exactly. 

the thing what upset me most is that I called the professional company and before I paid for Arc I asked them to check if my TV is compatible with Arc for Dolby Atmos. 

But they just tried to sold the product( 

thank you very much for reply! 

How do you watch Netflix? From your TV’s internal apps or from an external media device?

I watch from TV directly. 
 

oh!! Are you saying I can get Apple TV or other watching stick for Dolby Atmos?? But they would be connected in the normal USB port on my TV so I still don’t understand how they will deliver the DA sound(( 

If you use an external media device like an Apple TV 4K or Roku Ultra, you could get the HDFury Arcana that would allow those media devices to bypass your TV’s audio limitations and send Dolby Atmos audio directly to the Arc. I use the Arcana with my 8-year-old TV and Sonos Arc and it works great.

OMG! The angel sent you to me!!! 

I just read about HDFury Arcana and it’s awesome!! 
looks exactly what I am looking for! 
 

Just to be clear-I need to get both- Apple TV 4K box and HDFury Arcana box, right? And they will go together nicely with each other? 

Two thoughts;

1. buying the Arcana and an Apple TV is not far (pricewise) from buying an new TV with eARC - you could also consider that option
2. if you have been ill-advised by the company you bought the Arc from, you should be able to return it.

Oh.. that might the option also. 
I don’t know why I used to think that TVs are expensive. 
 

And with new eArc TV I don’t need to get Apple TV? 
 

the company from whom I got Sonos keep saying that I have a Dolby Atmos sound. ‍♀️‍♀️‍♀️
 

Clearly I need to escalate the issue to Customer Right support and it’s a lengthy process(((

A quick question to the lucky guys who have Dolby Atmos) 

Any changes to dialogue? Mostly in movies there are dialogues. 
Are you able to hear that one person on the left is 2 metres away from the person on the right or something like that? 
not the flat dialogue sound?

Yes, you need an external media device that supports Dolby Atmos audio, like an Apple TV 4K, to connect to the Arcana. The Arcana then connects to your TV and to the Arc. Be sure to get some good quality HDMI cables to connect everything. I am using these KabelDirekt cables: https://www.amazon.com/gp/product/B07CMF1VJZ/
 

Any changes to dialogue? Mostly in movies there are dialogues. 

Most of the dialogue will come from the center channel speakers on the Sonos Arc. If you have trouble hearing the dialogue, the Arc has a Speech Enhancement setting that will boost the audio frequencies associated with the human voice and a Night Sound mode that reduces the intensity of loud sounds while increasing the level of quieter sounds, making dialogue clearer. IMO, the Arc does a great job with dialogue.

One more thing… since the Arc uses two upward firing speakers to play the Dolby Atmos height channels and relies on bouncing audio off of your ceiling, don’t expect a dramatic height effect when watching Dolby Atmos movies. And if you have high or vaulted ceilings, expect the height effect to be even less pronounced or even non-existent.

Got it! 
Thank you very much for your help! 
now I left with decisions-get a new TV or get ATV and arcana or just leave as it is. Sonos is already improvement compared to my TV speaker.  

And yes, I am using speech improvement option and night mode on Sonos arc . Don’t know if it’s working or not