Dolby Atmos codecs on Sonos Arc

Hi @takriel.

Thanks for reaching out and welcome to the community! Let me check it for you.

Dolby Atmos can do two types of surround sound signals: 

• Dolby TrueHD

• Dolby Digital Plus (DD+)

Most Dolby Atmos audio can be played through HDMI-ARC using the Dolby Digital Plus (DD+) codec. HDMI-eARC is required to play lossless Dolby Atmos audio using the Dolby TrueHD codec.

HDMI eARC supports the latest, high-bitrate audio formats such as Dolby Atmos, Dolby Digital Plus, and Dolby TrueHD.

ARC and eARC are protocols responsible for sending audio over an HDMI cable to home theater sound systems like Sonos Arc.

Arc uses the Enhanced Audio Return Channel (eARC) next-gen version of ARC implemented in HDMI 2.1.

The main benefit of eARC is greater bandwidth and speed, which enables hi-res audio formats like Dolby Atmos.

You may see this support article to learn more about getting Dolby Atmos on your Sonos Arc.

If you have any questions,  feel free to reach out.

You didn’t even answer his question.  What’s the deal with getting differing Dolby signals?  If I set to auto Sonus app says “Dolby Atmos,”.  Setting to pass through shows Dolby Atmos (DD+)

which is the correct/best setting to use?

Keep the TV set to passthrough. Dolby Atmos via Dolby Digital Plus is what you should be getting from Netflix.

It is my understanding that Dolby digital plus is lossy, Dolby Atmos is supposed to be superior

@Ggnore Netflix (and other streaming services) only carry the lossy form of Dolby Atmos via Dolby Digital Plus. There is too much audio data to stream the lossless form of Dolby Atmos through streaming services. If you want lossless Dolby Atmos via Dolby TrueHD, you need to get a Blu-ray player.

I understand that, so is it a bug that when I have passthrough set to auto it just displays Dolby Atmos, and not Dolby Atmos DD+?

With the Auto setting, I think your TV might be detecting the highest quality audio the Sonos Arc can output and converting whatever audio signal it receives up to a “Dolby Atmos” signal even though it may or may not actually be Dolby Atmos. TCLs with Roku TV and newer Roku Ultras do a similar conversion. Just set your LG TV to Passthrough and you are good to go.

That’s hilarious that they just gave him a canned response.  Not even close to answering his question.

-JR

Is Sonos ever going to chime in here?

@Ggnore Did you see my response above? The LG is probably automatically converting incoming audio to the best format supported by the Arc. You don’t want the TV to do this conversion so don’t use this setting.