Some are getting it to work. Maybe set the Bluray player to bitstream and let all the devices sort it out.

https://en.community.sonos.com/home-theater-228993/lpcm-and-4k-blu-ray-players-6850675?postid=16488025#post16488025

I’ve got the same setup. Can’t get it to work either for DTS blurays. Have run out of settings to try on 820 and C9. Nintendo switch and PS4 gaming is fine and outputs LPCM 5.1/7.1. 

Same for me. I have a LG C9 and Sonos Arc with 2 one sls. I can get multi channel from my PC, PS4 and PS5; I set the the Sonos Arc to Passthrough, the devices to LPCM and the app shows that I amn receivng 5.1 channels. However. my Panasonic UB820 shows as PCM stereo when I set the DTS to PCM. I’ve tried leaving everything unplugged overnight and tried other settings but no joy.    

I also have the same setup. Instead of losing more hair, I finally gave up and purchased the Sony UBPX700, which also has Dolby Atmos and Dolby Vision.  It’s very inexpensive and it works. I am now getting LPCM 5.1/7.1 when playing DTS discs.  Until the issue is fixed, I will use the Panasonic for Dolby encoded discs and the Sony for DTS encoded discs.

I think I found the solution.  The player and the Sonos app are showing 2 channel, but I’m getting surround.  Try it and let me know your thoughts.

My set up:

TV: LG C9 

Player: Panasonic UB820

Sonos: Arc, Gen 3 Sub, One SL x 2

Audio settings on the UB820

Digital Audio Output - DTS: PCM

Downmix: Surround Encoded

Audio Settings on LGC9

HDMI ARC

Digital Sound: Passthrough 

eARC: On

One thing to check is what type of DTS track you are trying to play. I was checking the 420 specs and it can't decode DTS:X only bitstream it. It can decode DTS-HD tracks. The 820 will be same I'd expect.

I have a LG CX with Sonos arc and 2 ones as surround and a UB820

Watching Tenet last night I couldn’t get anything other than 2.0 to show on the Sonos app despite fiddling with the Panasonic and LG settings (connected via eArc) so infuriating. I had some sound coming from surrounds but all dialogue from the arc so I assume this was 2.0 

Have you set the DTS setting on the UB820 to PCM?

Yep tried both still shows stereo pcm 2.0 on the app 

DTS must be set to PCM. Also, try turning off Secondary Audio.

Set your TV to these settings:

1. Turn on SIMPLINK. This can be done by:
   1. Following the directions during your TV’s first-time setup process.
   2. Heading to All Settings -> Connection -> Device Connection Settings
2. Change your Sound Out to HDMI ARC
3. Go to All Settings -> Sound -> Additional Settings and turn on eARC.
4. Under All Settings -> Sound -> Additional Settings -> Digital Sound Out select “Pass Through”

I have tried setting everything to Bitstream, no dice.

No joy, indeed.

This is news to me… can anyone else confirm that the UBP-X700 passes LPCM 5.1 from DTS sources?

I can definitely hear sound occasionally from the rears depending on which settings I select on the C9 and UB820, but it’s just not… right. Way too much coming from the center only, it’s definitely not 5.1 surround.

Similarly, I can confirm that the Apple TV 4k (5th gen) passes multichannel 5.1 PCM for me no problem, in fact it defaults to 5.1 PCM for non-Atmos sources now.

This is a great point, thank you for this. After doing some research, indeed the UB820 supports decoding for everything up to and including DTS-HD MA, but DTS:X (and Atmos) is bitstream only. I checked and all of the DTS discs that I’ve tried so far have been DTS:X, so I tried a DTS-HD disc hoping that it might pass 5.1 PCM properly and… nope. Still PCM 2.0.

I’m beginning to think that this is more of a UB820 problem than an Arc problem, because with any DTS/DTS-HD/DTS-HD MA/DTS:X source I’m seeing PCM 2.0 output listed under Playback Information. Is the UB820 unable to pass multichannel PCM? Or is there some sort of EDID/CEC mismatch that is leading it to think that multichannel PCM is not supported on the C9 and/or Arc? At present, in my testing, it isn’t even sending 5.1 PCM... so the blame doesn’t seem to lie with the Arc (yet).

I have a Sonos Arc and UB820, and I get multi-channel LPCM audio playing through my Arc from ALL of my DTS-HD Master Audio Blu-ray discs. More than likely, the problem is your TV, HDMI cable, or TV settings.

To be clear, I mean the Playback Information menu on the UB820, not the Sonos app. I can see the DTS-HD soundtrack (or DTS:X or whatever it may be..) and the output is always showing PCM 2.0, so the issue appears to be on the UB820 side rather than the Arc. Since multichannel PCM is working well with other devices mentioned upthread (PS4, PS5, PC, ATV 4k), this does seem to isolate the UB820 rather than the Arc.

It is not a UB820 problem. See my post above.

So far you are the only person who seems to have this working properly. Which TV make/model are you running? Would you mind sharing your exact settings on the UB820 and your TV?

I have a seven-year-old Panasonic ST60 plasma with HDMI ARC only. So I added the HD Fury Arcana device between my TV and the Arc that acts as an eARC connection.

Digital Audio Output settings on the UB820:

• Dolby Audio: Bitstream
• DTS/DTS-HD: PCM
• Secondary Audio: Off

Yep, we’ve all got DTS/DTS-HD set to “PCM” and Secondary Audio set to “Off”. Still PCM 2.0. Sounds to me like the HD Fury Arcana is doing a better job with the handshakes, because the same settings on the UB820 are not working properly with the C9 via eARC. Have you been able to get multichannel PCM for any discs encoded DTS:X?

I just tested my Ex Machina Blu-ray and set the audio to DTS:X. The Sonos app says Multichannel PCM 7.1 and the UB820 says PCM 7.1.

I have the same issue.

I have the LG C9

Got the Arc last week

and got the UB820 today.

Have tried everything but can only get PCM 2.0 output.

UB20 set to output DTS as PCM

TV HDMI is set to Bitstream (tried PCM too); Sound output is set to eArc and pass through.

I’m not an expert at this but reading elsewhere I understand, the Arc needs to be able to receive a LPCM signal for multi channel surround, as opposed to PCM (which is 2.0 channel only?)

Can the UB820 definitely do multi channel LPCM?

There is a difference between PCM and LPCM, but both can carry 5.1 or 7.1 channels. Since GuitarSuperstar is getting PCM 5.1 or 7.1 from the UB820 as described above, then it sounds like a handshaking issue to me since the only difference between our set-ups and settings is the HD Fury Arcana...

Thanks for all your suggestions! I have a LG CX, so therefore cannot be the TV! HDMI cable has never produced any issues so i don’t think its that either so it HAS to be something relating to the settings.

Panasonic settings:

All audio settings are set to Bitstream with the exception of DTS which is set to PCM as you suggest. Secondary audio is turned off. I also have surround sound encoded or whatever it is enabled, i presume this is correct?

TV settings:

Output HDMI ARC (Automatic)

Digital Sound: Passthrough 

eARC: On

Thinking out loud - if people are getting multi channel LPCM using Switch/PS4 etc with the C9 and Arc, then doesn’t that mean the issue must be with UB820 or the type of PCM the UN820 is sending out?

If I get the chance I will try this using a Samsung tv in the other room. I think it has ARC (not eARC) but hoping I’ll at least be able to see if UB820 is sending 5.1 PCM or if it’s still 2.0

I spoke to Sonos support this morning and they think LG is to blame, pointing me to this article

LG CX DTS Incompatability

Wouldn't be surprised. Everyone is looking to streaming which has pretty much become Dolby ? Sony is still  supporting DTS I believe.

If the UB820 is set to convert the DTS audio to PCM before it passes through the LG to the Arc, then the DTS incompatibility problem with the LG TV shouldn’t be an issue.