Your problem is unrelated to the HDMI connection not being eARC, your eARC cable is in the right place.

What audio settings are on the Apple TV? Needs to be at least DD 5.1.

I assume the Frame is set to not use its built-in speakers.

Hi @controlav thanks for your reply. The audio settings on the Apple TV are set to Auto and it says “Dolby Atmos available”. Frame is set to output sound to eArc / receiver (Sonos Beam). 

ATV settings sounds good. Could just be yet another Frame bug, but I had assumed Samsung had fixed all of those by now. rtings.com doesn’t list anything too weird for this Frame. I am assuming you are using HDMI port 3 for the eARC connection.

Yes, the eArc connect works fine for TV played content, like the native Netflix app on the TV itself - when I play from that (or any other native TV app) the audio plays correctly and the Sonos app shows Atmos or 5.1 accordingly. The problem is when I play anything from the Apple TV app - it invariable results in Stereo PCM audio showing on the Sonos app. So frustrating after spending so much on this set up.

Hang on, you are talking about the Apple TV app, or a physical Apple TV? If the latter then yes, that is much more likely to not work than any built-in apps as it requires the EDID handshake to work correctly between the ATV and your TV.

Another thought: HDMI cable to Apple TV. EDID signalling is a bit weird, an old cable may well not work. Make sure its a modern cable.

On the TV settings, make sure HDMI eARC mode is set to Auto and the Digital Output Audio Format is set to Dolby Digital Plus.

On the Apple TV’s audio settings, set Change Format to Off and set Dolby Atmos to On under Immersive Audio. The alternative option is setting Change Format to On and setting the Audio Format to Dolby Digital.

I have the same setup as OP. Samsung Frame 55” 2021, Apple TV 4K (2017), Sonos Beam gen 2 (2021), 2x Sonos One SL as rear speakers, but no Sub. ATV connected to TV with a brand new high speed HDMI cable. Sonos Beam connected with the HDMI cable that comes with the Beam.

Sometimes there is no sound at all, most of the time there is sound, but the Sonos apps says “Stereo PCM” when played content from ATV apps. Samsung Frame Apps are working without any problems with Dolby and Dolby Atmos.

If I set ATV audio settings to “change format: off” the Sonos app says “Stereo PCM”. If I change it to “change format: on, dolby digital” Atmos is turned off.

And I know another guy with the same setup with the same problems. I didn’t expect these problems as I thought this is a pretty common/mainstream hardware setup. Conclusion: Use the Samsung Apps and turn ATV off, despite the better apps and performance.

@MikeLieser Can you post a screenshot of your current TV audio settings?

Sure. 

Apple TV 4K 2017 (A1842, tvOS: 15.2 - newest) Audio Format Settings:
Change Format: Off
Dolby Atmos: On

Samsung Frame 55” 2021 (Firmware: 1805 - newest) Sound Settings:
Sound Output: Receiver (HDMI-eARC)
HDMI eARC-Mode: Auto
Digital Output Audio Format: Auto
Dolby Atmos Compatibility: On

You wrote: “On the TV settings, make sure HDMI eARC mode is set to Auto and the Digital Output Audio Format is set to Dolby Digital Plus.”

But Dolby Digital Plus ist not available in this menu for me. Just PCM, Auto, and Pass-Through. The settings are looking fine to me, as Auto should just work in my opinion and the TV apps are all working fine together with the Beam. And I tested all combinations of settings and without success.

I have the exact same problem with my newest model frame and Apple TV.  Setup is perfect.  I can get my Dolbyatmos from appletv to play well through my beam, but cannot get regular 5.1 content to play.  Video is shown but no audio and sonos app shows no signal.   This is with pass-through enabled and all appletv settings optimized.  
 

if I use settings “change audio” to 5.1 on appletv then then all content plays fine in 5.1 but I lose atmos.
 

seems like I can’t have BOTH Atmos and 5.1 content playing well with standard settings on appletv and Frame.  Very frustrating  
 

If that is any help with your diagnostic, I’m having the opposite issue with my setup. I have an Apple TV 4K connected to a Samsung QN90A, itself connected through earc to a Sonos Beam first gen (doesn’t support Atmos). When I play atmos content on Apple TV, sound only works intermittently, if at all. I had to change the audio setting to re-encode all audio to 5.1. With re-encoding, audio plays fine, but sound isn’t as rich as when no encoding is occurring. It seems to be a known issue, there are a few threads about this on Apple forums and reddit. The problem seems to affect users regardless of the soundbar/audio setup they have, so the problem is more likely to be between Apple and Samsung. I have yet to find a fix for this.

I actually landed here when wondering if upgrading to the Beam 2 would help, but seems that might not be the case.

Hi,

I have exactly the same issue with my Sonos Beam Gen2, TCL TV (eARC) and my Apple TV.

Atmos is working like a charm on Netflix, Disney+… but as soon as the content is 5.1, Apple TV pushes PCM stereo to the Beam.

I need to disable Atmos and force 5.1 on Apple TV in order to have 5.1 on Sonos.

Did you find a fix?