Play a movie in 5.1 on Netflix while you change the Digital Output Audio Format setting.

That’s the problem, Netflix won’t let me. Netflix apparently does not detect dolby equipment and won’t show dolby 5.1 in the selection menu. I know it did when I still had my ‘old’ stereo attached. I am now considering to hook up my old stereo to confirm that the selection for dolby 5.1 will re-appear. Or maybe attaching the ARC with the optical adapter iso the HDMI to see if that makes any difference. 

As long as I can’t select dolby 5.1 input, I can’t verify wether the problem is with the input or some strange miscommunication between my Samsung and my ARC (which is wat it points to now).

I have been on the phone with Samsung yesterday, but they could not offer a solution, except considering bying a newer tv, even though my TV has 2.1 HDMI and it all should work. I will reach out to Sonos later this week to see if they can help me.

Is the Sonos Arc’s HDMI cable plugged into the port marked HDMI ARC on the TV? It probably needs to be. That might make a difference. 

Yes, it is. Otherwise the TV would not recognise the speaker at all. 

Okay. To be clear from your posts, you’re playing built-in apps from the TV itself, rather than from an external device like an Apple TV box or Firestick? 

When trying to change the Digital Output Audio Format, are you actually playing Netflix content that definitely is in Dolby 5.1 rather than just being on the Netflix menu screen when trying? This may be what you said, but I’m not 100% clear from the earlier post. 

If so then when you go to Settings - Sound - Expert Settings - Digital Output Audio Format, you’re only being presented with PCM as a non-greyed option, correct?

A couple of shots in the dark but:

Settings - General - External Device Manager - HDMI UHD Color, is this set to ON for the HDMI ARC input? It largely refers to UHD picture signals of course but would be worth ensuring is on to maximise the data transfer so the TV knows that HDMI can handle it. 

Settings - General - External Device Manager - Anynet+ (HDMI-CEC) - is this set to ON? 

As I said, may not of use but just looking at all options…

Hey Rhonny,

Sorry for late reply. Thanks for taking the time.

I checked all the settings. What it looks like is that the TV does not see the ARC as a surround capable system and therefore Netflix does not see that either. In the Netflix sound-and-subtitle selection menu on my computer I can select surround 5.1, but in the Netflix app on the TV I cannot. The option is just not there. I could with my previous sound set (regular Yamaha receiver with 5 speakers).

So the 'smart’ systems are a little to smart for my good, as there are no options to overrule them. There's only one thing I haven't tried yet and that is to see if there's a firmware upgrade for my TV. If that's not possible or when it does not bring a solution to my problem, I am left with no other option than to buy another TV (I can no longer return the ARC and I don't want to anyway).

It will not be a Samsung.

Good luck. I have a more recent Samsung with an Arc. Works fine!!!