LG 60UH6035 > Apple TV 4K > Arc : No Atmos

Hi @Forstal,

Welcome to the Sonos community and thanks for reaching out to us. Let me share some information to help you out. 

The Sonos Arc can play Dolby Atmos audio. ARC and eARC are protocols responsible for sending audio over an HDMI cable to home theater sound systems like Sonos Arc. Sonos Arc must be connected to HDMI ARC or HDMI eARC to play any Dolby Atmos content. Not all TVs have HDMI ARC or HDMI eARC, so check your TV’s user manual to see which HDMI connections you have. Your TV must be Dolby Atmos compatible.

Getting Dolby Atmos audio can also depend on the physical source device playing the content and the format or output must be set to one of our supported home theater audio formats. Some TV and movie streaming services now support Dolby Atmos. Please note that even if a service supports Dolby Atmos, some shows and movies may not have Dolby Atmos audio. Check with your streaming service provider to see if they support Dolby Atmos.

Hope this helps. We can wait for suggestions and feedback from our Sonos community members, they might provide their inputs about this. If you need help with any other information, please be sure to let us know.

On your Apple TV 4K, go to Settings > Video and Audio and select Audio Format. Under Immersive Audio, check that Dolby Atmos is ON.

You might also try a different HDMI cable for your Apple TV.

There is also a very good possibility that your TV cannot pass through Dolby Atmos audio.

Before you purchase a new TV, have you considered the HDFury Arcana? It allows your Apple TV to bypass your TV’s HDMI ARC port and send audio directly to the Sonos Arc. https://hdfury.com/product/4k-arcana-18gbps/

I addressed most of that, except for your statement about tv Atmos compatibility.

As far as I understand, any TV that is HDMI 1.4 compliant can pass a DolbyDigital 7.1 stream (aka DD+), without regard to the package its carrying, and Atmos object data is treated the same as anything else in the stream by the 1.4 compliant circuit. The only thing I’m aware of affected by transfer via 1.4 is closed-captioning, which is a function of the CC decoder looking for a substream that doesn’t exist in a standard 1.4 compliant stream.

Since this is the internet I’m sure someone will correct me if this is wrong...

If this TV were not 1.4 compliant, I’d agree with you about the pass-through. As far as the cable, its a MonoP 15428 - 18GB/s, which is HDMI 2.0 spec. I know that with that in place my aTV 4K reports all HDMI tests passed, and my aTV works at its top capability.

There is no setting in my Apple TV 4k for Immersive Audio. Other people have reported this missing as well, and Apple’s only advice is “If you don't see Immersive Audio and Dolby Atmos as an option, you might need to change how your home entertainment system is set up.” and there’s no further explanation. I have an aTV 4K hooked to my LG display via standard HDMI, and the Arc is attached to an HDMI ARC port, which is exactly what Sonos tells me to do.

I looked at the Arcana, but frankly if I have to spend $200 plus shipping on a box that is back-ordered with no guarantee on shipping, it seems I should just get a new TV. There’s a 70”  Vizio available thats fully buzzword compliant, and it has 3 HDMI ports including eARC, which ends the whole problem.

I switched the HDMI cable out to a brand new 18GB cable and re-ran the HDMI test in the Apple TV 4k. After three minutes it reported “Your HDMI connection has improved”.

I figured that was it, so I started an Atmos movie on Disney + and checked my Sonos app - still showing Dolby Digital 5.1, and after the movie was over the title card no longer showed Atmos.

I considered the Arcana, again, but I’ve decided against it. It has a single input, so what do I do when I switch to a Blu-ray? Switch cables? Add an HDMI switch?

This is getting too complicated for something that should be easy.

If you purchased the Arcana and wanted to connect multiple devices to it, you would need to purchase an HDMI switch. This is my setup:

Your aTV is two generations older than mine - so is your tv. The newest thing you have there is the Arcana and the Sonos…. how are you getting Atmos now?

I get Dolby Digital Plus/Dolby Atmos from Disney+, VUDU, and Apple TV+ from my Roku Ultra.

I get Dolby TrueHD/Dolby Atmos and multichannel PCM from Blu-rays and UHD discs on my Panasonic UB820 Blu-ray player. I also can get Dolby Digital Plus/Dolby Atmos from the built-in Netflix app from the UB820 too.

Because my TV is from 2013, I wouldn’t be able to get any of this without the Arcana.

Sorry I was just focusing on the Apple TV. I know nothing about Roku.

Doing it your way would end up costing an extra $300 and add a few more connections to the rats nest under my TV.

There is no reason why my TV would be causing the problem so I think there is something wrong here, either with the aTV or the Sonos. I wish Sonos had put a pass-thru HDMI port on the Arc instead of us having to go through contortions to make things work.

I’ve been searching the web for info on “Apple TV 4k immersive audio doesn’t work” and similar terms, and I just get people who quote the single Apple support doc or link to it. One guy said that only the newest TVs would work because “Apple used a high bandwidth form of Atmos”, so I guess he never read the technical specs on it  - its spelled out pretty clearly that the Atmos is carried by DD+, not TrueHD, so its the compressed Atmos. Again, it shouldn’t be a problem on an HDMI 1.4 connection.

AppleTV uses high bandwidth for ATMOS and you need HDMI eARC for this. HDMI ARC will only support up to Dolby Digital Plus.

Dolby Digital Plus can support compressed ATMOS, but AppleTV will only pass Dolby Digital 5.1 via HDMI ARC.

I only have HDMI ARC and I have never seen the immersive sound option on my AppleTV 4K, this is because the TV and AppleTV are negotiating the connection and AppleTV sends 5.1 as it does not detect HDMI eARC.

options are the Arcana or a new TV that supports HDMI eARC