Sound cutting in and out on Sonos Arc after playing Dolby Atmos content on Apple TV 4K


Sound cutting in and out on my Sonos Arc after playing Dolby Atmos content on Apple TV 4K 

I’ve had my Sonos Arc and Sub Gen 3 for about two weeks now and I’m very satisfied with the sound quality, but I’m having some very annoying issues with audio cutting in and out… 
I have the latest LG OLED TV, a LG GX (same as the CX, just wall mounted). The only two boxes I have hooked up to my TV is an Apple TV 4K and a PS4 Pro, but I’m having sound issues on my Apple TV.
Before I explain the problem, yes, I’ve pretty much done all the troubleshooting I can do. Plug everything in and out, check that the cables is properly connected, updated everything, the Arc, TV and Apple TV, everything should be up to date as I’m writing this post. 

 

Okay, so here’s the issue, with a half ish solution. 

My issue: 
If I play any content that supports Dolby Atmos on iTunes, Apple TV+, Netflix etc. and try to play some music through the Apple Music app or watch any video on YouTube on my Apple TV after that, the audio cuts in and out every other second. This even happens after playing a Dolby Atmos movie on iTunes and when I go back to the movie menu, the audio starts to cut in and out. It doesn't help to turn the TV and Apple TV on and off and it doesn't help to just restart the Apple TV itself. 

 

The half ish solution:

The only fix that I found that worked, is to play a movie that is in 5.1 after playing Dolby Atmos supported content. If I do that and then go into Apple Music or YouTube, the audio is fine and it doesn't cut in and out every other second. 

 

The issue: 
So it seem like the Arc might have an issue going from Dolby Atmos straight over to stereo sound. But going from Dolby Atmos to 5.1 or from 5.1 to stereo works just fine.
It work perfectly the other way around, from stereo to 5.1 or Dolby Atmos. The only thing I hear then is a little loud zippering or buzzing sound, but I guess that’s just because the Arc is switching the sound receiving signal? If that zippering / buzzing sound shouldn't happen, let me know. 

 

The funny part: 

Here’s the the funny part though, if I play something in Dolby Atmos on my Apple TV and after that play a YouTube video on the built-in YouTube app on the TV, the audio is fine. Same if I AirPlay music to the Arc. So I’m a little unsure if there’s something that has to be fixed from Sonos’s end or Apple’s? 

I’m seeing a lot of people on here tags @Ryan A  and @Kyle A, so I’m gonna do that too, seeing as they come up with a lot of good answers. 

If anyone else has had similar issues, let me know.


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110 replies

Hello, I’m writing from Colombia.  I have the same problem. LG CX + Apple TV 4K + Sonos ARC + 2 Sonos one LS. LG firmware 03.11.30 no updates 

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Hello, I’m writing from Colombia.  I have the same problem. LG CX + Apple TV 4K + Sonos ARC + 2 Sonos one LS. LG firmware 03.11.30 no updates 

Can you get the new 3.21.09 firmware, that seems to have fixed the issue you have, not had the issue since installing this firmware on my cx, but did only install it yesterday.

Although this new firmware does dim HDR game mode, and LG have said they will be fixing that in another firmware in the coming weeks, so if you game on the CX you might want to wait for the next firmware. 

It is fixed with the new Netflix app on AppleTV released 1/19/2021.

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I am trying to watch appletv via HDFury Arcana from Roku .     When I am in the settings for AppleTV there is no choice to change audio output.  So it’s silent.

any ideas?

 

Userlevel 7

I am trying to watch appletv via HDFury Arcana from Roku .     When I am in the settings for AppleTV there is no choice to change audio output.  So it’s silent.

any ideas?

 

To clarify, are you using the Apple TV+ app on a Roku device? If so, what are the audio settings on your Roku set to? What specific Roku device are you using?

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I have a Roku Streaming Stick + which is meant to supply sound in Atmos

The audio setting on the Roku is Auto DD+.  I get sound from all the other apps except AppleTV

I read elsewhere to change the audio in Apple tv app itself but that is not an option 

 

Any ideas

 

 

Userlevel 7

@Tudor Does your Arcana have the latest firmware installed?

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So went to Roku audio settings.  Audio was already on auto DD+, But the HDMI was on auto.  I changed this to DD+, DTS and then I got great sound

Thanks for pointing me in the right direction

 

Userlevel 7

@Tudor Glad you got it working. FYI, the Arc doesn’t support DTS audio so you can have the HDMI setting on DD+ and it should work too.

Confirmed the HD Fury Arcana resolves the issue 100% so it’s definitely an issue with the lossy encoding of Atmos over Dolby digital plus pass through over HDMI arc instead of eArc to the Sonos arc. Likely some edge case between how Netflix encodes Atmos and how LG and other manufactures pass through over ARC.

 

The Arcana splits the HDMI signal, sends audio to the Sonos Arc over HDMI eArc and video to the Display over HDMI arc. I still have volume controls but now I also have upscaling, reliable Atmos, and the ability to force HDR. Love it. Expensive, but worth it overall. 

 

Technically speaking, Sonos might be able to program the arc to handle this edge case. Not necessarily on them to do this though.