I have never been able to pass LPCM 5.1 7.1 from the Panasonic 820 through my LG CX to Sonos ARC. only PCM 2.0. Thanks to someone else’s post in this community, I found the very affordable $150 Sony X700/M player w/ great IQ BTW will pass LCPM 5.1/7.1 from the player through the LG CX TV and to my Sonos Arc for my DTS: HD only blu-rays. It was too late for me to return the Panasonic, so I use the Panasonic 820 for all my Dolby Atmos blu-rays discs HDMI 3 and the Sony player for DTS only blu-rays HDMI 4. 

FYI - LG have just released an update for the CX (04.40.10) which appears to (mostly) resolve this issue. 

Before, I only got stereo PCM passthrough from the 820 for DTS discs - and had to get the HDFury Dr HDMI 4K and code with a custom EDID to get the full LPCM 5.1/7.1.

However - with the new LG update I can get LPCM 7.1 passthrough without the need for the additional Dr HDMI 4K device. For some reason, the Sonos app is still saying that it’s LPCM 7.1 (rather than LPCM 5.1) - but I guess this shouldn’t be a problem since the ARC is now able to downmix from 7.1 to 5.1 correctly.

N.B. - if I set my Xbox Series X to uncompressed 5.1, the Sonos app now says LPCM 5.1 (before it said LPCM 7.1) so I know it can work as it’s meant to! It must mean that there’s still something not quite right in the interface between the LG CX and the UB820 to cause the UB820 to put out 7.1 instead of 5.1 - but as I said, at this point it doesn’t really matter as what we hear should be the same anyway.

It would be great to hear if this works for anyone else who had the same issue with the LG CX and the UB820! 

I can confirm your findings on latest 4.40.10 firmware for CX. With my particular devices I never had a problem passing LPCM, but I always got multichannel pcm 7.1

Xbox series X when set to uncompressed 5.1 now correctly states multichannel pcm 5.1 (before it said 7.1)

My Apple TV 4K still says multichannel pcm 7.1 for all 5.1 content though.

So there has been fixes, but its weird that some devices still report differently.

@Woj  / @ledzep1

Hello. Are you already running on Sonos 14.10? If you have time, can I please ask for you to set your Xbox to uncompressed 5.1 and have it run for like 2-5 mins and see if you encounter audio dropouts? Just ensure that the Sonos app reads the audio format as “Multichannel PCM 5.1” the entire time.

Reason I’m asking is I’m having issues post-14.10 where Multichannel PCM 5.1 drops out once every 1-2 minutes. I’ve tested on PS5/PC→ LG C1→ Beam 2 (so could be a me / beam only problem). PC set to Dolby Atmos for Home Theatre reads on the app as Dolby Atmos (MAT) with no dropouts. PC and PS5 set to LPCM 7.1 ch reads on the app as Multichannel PCM 7.1 with no dropouts. However, PC and PS5 set to LPCM 5.1 ch reads on the app as Multichannel PCM 5.1 with the aforementioned dropouts.

So this only happens when the Sonos is receiving the Multichannel PCM 5.1 format. I came across this issue while using my PS5 as a bluray player where I transcode DTS-HD MA 5.1 to LPCM 5.1. 2 weeks ago, a couple of days before the Sonos 14.10 update, I was able to watch a bluray at Multichannel PCM 5.1 without any issue. Then yesterday, I tried watching another film and encountered the dropouts. The only difference with my setups is the Sonos has since updated to 14.10 so I’m inclined to believe that it’s the culprit.

If this is too off-topic, perhaps you can send me a PM for your response. Thank you. 

My setup is Sonos Arc (14.10 firmware) + LG CX (04.40.10 firmware) + Panasonic 820. After updating to those firmwares the Sonos app is now saying Multichannel PCM 7.1 (and the sound output sounds multichannel now too). My audio settings on the CX and 820 are set to their respective defults. Glad to be able to finally use my equipment fully.

Just installed the update on my LG C1 ( v 03.33.11), and I still have the now famous issue with DTS and Stereo PCM on Panasonic UB820.

Seems that the last update solved the problem on LG C9 and CXseries but not on C1 and C2 :-( 

The good news is that this update show that the issue is on LG side and/or can be fixed by LG… on products that still receive updates (considering the fact that a new firmware update for the UB820 will probably never happen, it’s a good news).

Just hope that a future new firmware update will solve the issue on LG C1 and C2 series.

For the price of an ARC and an a Arcana your are not far off a Sony HT-A7000 and no issues at all. Hard choice to make..

There’s a comparison of those two soundbars here from rtings.com…

https://www.rtings.com/soundbar/tools/compare/sonos-arc-vs-sony-ht-a7000/13760/27046?usage=8767&threshold=0.10

It’s not really the point here, considering the fact that the issue we’re talking about is due to the Panasonic UB820 coupled with a LG C9 / CX / C1 / C2.

There’s no debate here about the choice between an Arc or another product ;-) 

I’ve just checked my C9 and UB820 and still receive PCM Stereo rather than PCM Multi channel (I get LPCM multi channel for my PC and PS5). Is anyone now receiving PCM Multi channel rather than stereo when playing DTS HD MA blu rays/4ks through their player?

Mixed feeling about it. It seems that the last LG update has solved the issue in some cases, as for @movie_monster for ex, but the issue is still here for others, like me.

It’s clearly a problem between LG Oled TVs and Panasonic UB820 player; has changing the player (for a Sony X800-M2 or an LG UBK90 for ex) will immediatly solve the problem, as changing the tv (tested on a Sony 55A90J on my side).

So a specific handshake issue between UB820 and LG Oled TVs seems to be the explanation; meaning that we need Panasonic and/or LG to update their firmware to definitly resolve this problem.

For information, I had an open ticket with Panasonic support since couple of weeks, with lot of Q&A by email with their support agents, who where in contact with internal software engineers (at some point I have gave them the link and it seems that they have read this topic).

Here is their final conclusion :

« The factory has been notified. Their point of view is that the problem is with the TV, not with UB820: The recorders do not have EDID. The TVs have EDID and update the audio part with the EDID of the Sonos sound bars. If the problem disappeared by converting the EDID of the TV with a special device, the EDID is "corrected" to conform to the HDMI standard. »

So, for Panasonic, the issue is on LG side.

By the way, this point from Panasonic support team may interest @GuitarSuperstar , who was deeply involved in this topic at some point

I’m confused : I bought an LG UBK90 to replace my Panasonic UB820 in order to be able to play my DTS BluRay disc in 5.1 PCM through my LG C1 and my Sonos Arc…

… and my DVD and BluRay DTS tracks are still playing in 2.0 PCM.

My UBK90 is set in Multi-Channel PCM, then I try to set the tv in bitstream and PCM but I still obtain Stereo PCM as a result.

Did I miss something ??

Be sure the TV settings are set to this:

HDMI Input Audio Format - Bitstream

Digital Sound Output - Passthrough

eARC Support - On

Hey all,

Has anyone yet got round the issue of DTS being unsupported when you have eARC turned on?

I have a B9 (which supports DTS), but the only way I can get DTS is either turning off eARC, or changing Secondary Audio (on the blu ray player) to On - but then that removes Atmos for those discs.

Funnily enough, when I switch the audio to play through the TV, it all works fine. So maybe the issue is partly on Sonos’s side too?

Do I have any other options apart from toggling eARC on/off every time?

EDIT: Also, I tried it with another Blu ray player, and still had the same issue. So I’m not convinced this is a handshake issue with the TV and Blu ray player - I think there’s a separate issue happening.

A new day ! 

For the first time ever…I am now able to pass through Multichannel/LPCM 7.1 from the Panasonic 820K  playing a 4K UHD DTS:HD disc through the LG CX TV to my Sonos Arc 🤩🤩

Something changed via recent firmware probably with the LG CX TV since the  Panasonic 820K has not received a firmware update in some time.

With the LG CX TV sound set to “pass through” I now see Multichannel PCM 7.1 when playing both of these 4K UHD DTS: HD discs on my Sonos App:

"Jurassic World Dominion"4K UHD DTS:HD

"The Revenant" 4K UHD DTS:HD

Previously I would only see PCM 2.0 pass through the LG CX TV with these DTS discs played on the Panasonic 820K player. 

Alas, no joy from my Panasonic 820 + LG C9 55”. I did update to the latest software today, and if what Panasonic says is right, then this is still a LG issue. I thought I saw someone with a B9 got DTS 5.1/7.1 to work, but maybe I read that wrong (just with eArc off). I do see that CX machines are working, so perhaps LG did not want to go back so many versions for fixes.

So, HD Fury still in the stack for me! Oh well. No complaints though since it does work.

(Also, separately, no issues with Xbox Series X streaming 5.1 or Atmos though the C9 to the Sonos Arc. That seems fine and while I don’t the Atmos test really shows off the imaging, it does track to position correctly.)

Forgive me if I’m misunderstanding your post as I haven’t read this entire thread but I have the LG C9 OLED and I get both DTS 5.1 and MC LPCM 5.1 to pass-through the TV, but I don’t have the Panasonic 820. I’m just using an old PlayStation 3 (slim). Is it DTS you’re trying to pass through?

TV firmware here is 05.30.11 (WebOS 4.5)

You've probably already checked this 100 times… but just in case something was reset at some point:

TV set to:  Sound = Passthrough 

820 Digital Audio Output set to: Bitstream, Bitstream, Off 

Yep, B9 works like a charm, but only if you turn eARC off. It’s a right pain having to keep toggling it back and forwards.

I have tried it with other Panasonic Blu Ray players though and have the same issue, and when I dug into it further I have a sneaky suspicion that something’s not right on Sonos side either. But I’ve not got round to going through support with them about it.

Some interesting comments from Sonos support today when I contacted them:

“Based on the diagnostic when the eARC is on the format of the audio being received by the Arc is Unsupported DTS4 when the eARC is off it transcodes to DTS.”

“Based on checking this Blu-ray player is not included in the list that we have that transcodes the audio format. This is not expected behavior and it requires further investigation.”

They want me to call the support line next week to delve into it further. Hopefully we can get more information on what’s going wrong.

So after speaking with Sonos over the phone, and doing diagnostics, they basically are saying that all/most of Blu Ray DTS is a version of DTS called ‘DTS4’, which Sonos don’t actually support.

And the reason I get it when eARC is turned off is because my TV then converts DTS 4 to DTS.

In case this is derailing this thread (which is more about C9 and the lack of DTS at all), I’ve made a new thread about DTS 4 - 

If you’re in a similar situation to me, and having to toggle eARC on/off to get DTS, please feel free to get involved in this thread.

I have the LG C9 TV and it passes-through the supported DTS 5.1 and for other unsupported formats like DTS-X/HQ, I simply switch/use the Mc-LPCM codec on the sending device.

Are you using the UB820 player? I know there’s a way to downgrade DTS-HD to DTS, but it does the same with Dolby too if you turn it on, so you lose Atmos and the like.

I mean, I can also get DTS 5.1 when I turn eARC off, but it’s a pain having to keep switching it every time (and remembering to switch it back on after you’ve watched a movie).