What specific UHD disc are you testing? What UHD player are you using? Do you have a premium Netflix subscription? If so, make sure the streaming quality in your Netflix account settings is set to High or Auto. Can you post photos of your TV’s HDMI and audio settings?

UHD - Sony X800M2 with 4k LOTR

Yes I have a premium subscription with Netflix for 4K HDR and Atmos Content.

Atm no I cannot post photo’s for the TV I am at work, the HDMI settings are Enhanced, Prioritize Audio Performance, and Dolby Digital Plus Output.

I should add - I tried already every combination of TV and UHD settings recommended online for the purpose of putting DD+ out through the ARC.  Had it so UHD handled the mix, no luck.  Had it so TV handled the mix, no luck.  Right now it’s configured that it sends the signal to the Sonos ARC now for it to work out the mix, no luck.  I also tried swapping my 18gbs cable to the ARC on the TV to the Sonos Arc, no luck.

Be sure Digital Audio Output is set to Auto and BD Secondary Audio is turned off on your UHD player.

I also don’t think the LOTR UHD has a DD+ track. It has a Dolby Atmos and Dolby TrueHD track. Since your TV is not equipped with eARC, the UHD player plays the core Dolby TrueHD track as Dolby Digital 5.1.

Your TV’s native Netflix app should be able to play DD+ and Atmos audio. The native Amazon Video app should also be able to play DD+. That’s what makes me think there must be a TV setting that needs to be adjusted. When you get home, send your settings and I’ll be happy to give you more feedback.

Those are my current settings.

Atmos TRUE HD for my TV is mixed down to DD+ (Atmos Lossy) on my TV, confirmed this in TV Info Panel when playing the UHD.  

Also confirmed on the most recent patch of my TV, that DD+ (Atmos Lossy) is passed through the standard ARC Port.  Pre-patch, DD+ was passed through ARC regardless of Atmos.

The only place it doesn’t say DD+ is in Sonos App.

EDIT** Regardless to how the UHD is handling, why when I play Altered Carbon on Netflix which is an Atmos track, on my TV is converted to DD+ (Atmos Lossy), TV info Panel on Netflix app (and for UHD) says Dolby Digital Plus 5.1 --- why doesn’t Sonos say Dolby Digitial Plus.

Send me your TV settings when you get home. We’ll focus on getting DD+/Atmos to work on Netflix first. Whether or not your TV can downmix a Dolby TrueHD track to DD+ from a UHD disc will be determined later.

Also, do you have any other Blu-ray or UHD discs? Some actually have a DD+ track (usually in another language). If you have one of these discs, it could come in handy for testing purposes.

Don’t mind the setup, just moved in - waiting for mounts.

So in the audio output I have 3 options-

Auto 1 - Send audio to device (unchanged)

Auto 2 - Send audio to device, after multi-channel mix

#3 - Send PCM only

I’ve tried both 1 and 2.

With the sonos sound system attached, I really am only given options that would be to detect a Sony Surround System, modify for Dolby Digital or Plus, and PCM Volume’s.

Did you say there is an HDMI setting? Can you set it to Enhanced?

Have you checked the Streaming Quality settings in your Netflix account?

Have you tried unplugging the TV and Arc from power for about a minute?

HDMI setting is set to enhanced

Streaming Quality only getting 1080p atm with current internet speeds (20d/1u)

I have not tried rebooting the ARC.

I will do a full TV reboot (system reboot, not just the restart) and rebooting the ARC by unplugging it.

I just got my couch today, as we were responding to one another - so about the mount my one’s on the wall and re-tune.  So will do this later and likely let you know tomorrow.

TY so far for input - if you think of anything else let me know! I’ll post tomorrow if any change.

The inability to stream 4K from Netflix could be the culprit. I believe DD+/Atmos is only streamed with 4K content.

Also, if you want to get lossless Dolby TrueHD/Dolby Atmos audio from UHD and Blu-ray discs, you should consider getting the HDFury Arcana. It allows the UHD player to bypass your TV’s limitations and send audio directly to the Arc. I have one and it works great.

https://www.hdfury.com/product/4k-arcana-18gbps/

Oh I have my eye on the HD-Fury, I just bought a house though - So most of my money has gone to appliances, and tools for the yard.  The arc was my one gift to myself.

In time I’ll get the arcana device, or a new TV.  We’ll see :)

It would explain the Netflix / Prime issue I see.

It doesn’t explain the downmix to DD+ from TrueHD though, then to no DD+ to the speakers.  Realistically I may be sniveling over DD+.

DD+ would be better heard in 7+ systems due to channel expansion, with likely minimal impact to sound over my 5.1 setup.  That is when comparing DD to DD+, the compression difference is probably so slight that I’d have to really listen for it - which would detract from what I’m watching anyways.

Just got my answer on a separate forum about the UHD Player, and it’s sad.

So apparently my TV does downmix the TrueHD to DD+ (atmos lossy).  However, due to limitations on processing in my TV, it DOES NOT passthrough DD+ that it down converted - It only passes on native DD+.  This again due to the amount of power it takes to down mix, then send through ARC is not sufficient without serious sound sync issues - only hope here is for a patch that optimizes this some how.

So for my UHD setup, I would need the HD Furry or a whole different sound system with an Amp that support TrueHD and then speakers that are compatible with the amp. 

As I love Sonos, I don’t intend to buy a whole new system - have a number of these speakers throughout my home.  When I do upgrade my surround, it’ll be after I build a mini theater into my spare room attached to the garage - and it will be a money soak on a very serious system.

So, tldr - TV isn’t powerful enough to downmix + passthrough ARC and you are likely correct about the DD+ from Netflix requiring a certain bandwidth.  As Netflix / Prime send a DD+ (Atmos Lossy) - as you know, streaming and compression.  So it technically is native from Netflix, which is how other people with my TV in the forums are getting a compressed form of Atmos from a streaming service.

Maybe my UHD player will release a patch to downmix before the TV, so it technically is DD+ native source - one day.

I wouldn’t be too concerned about the difference between DD and DD+. Like you said, the difference is minimal. But if I were you, I would definitely boost your internet speed so you can take full advantage of your Netflix premium subscription. And I would start saving some money and get the HDFury Arcana so you can experience Dolby TrueHD/Atmos from UHD and Blu-ray discs. Lossless audio really does sound phenomenal on the Arc. And with Sonos’ latest firmware update that allows you to adjust the height channel levels, lossless Dolby Atmos from the Arc sounds even more amazing. I would imagine LOTR in HDR or Dolby Vision with lossless Dolby Atmos would be a pretty awesome experience.

@GuitarSuperstar 

Confirmed Atmos was working in HBO, DD+ working in Peacock, looks like DD+/Atmos not working in Netflix… likely due to bandwidth.  This all started working after I completed a hard reboot of my TV - I saw in my Sync settings that it still believed the Sonos Beam was plugged in.

Right now the arcana is just not an option for me.  Be some time before I drop more ‘fun’ money on my entertainment system.  By the time I can, I’ll either be in the market for a new TV or there will be a wider array of eARC intermediary devices with better pricing options.