LG C9 + Arc + UB820 / Multichannel PCM for DTS Blu-Ray discs


Userlevel 1

I’m running an LG C9 with a Panasonic UB820 Blu-ray player, Sonos Arc + Sub gen 3 + One SL surrounds. The lack of DTS support on the Arc has been frustrating for non Dolby encoded Blu-ray discs, so I have been eagerly awaiting the multichannel PCM update.

It’s finally arrived (thanks, Sonos!) and I tried playing a DTS encoded Blu-ray and… no dice. Still stereo PCM 2.0. Has anyone running a similar set-up managed to get 5.1 PCM output from the Arc?

The C9 supports eARC and multichannel PCM, I’m using 48gbps HDMI cables that support up to 8k60Hz, all of the devices are up to date, I have the C9 set to PCM with eArc enabled, DTS output set to PCM on the UB820… I’m really at a loss here. Any ideas or suggested settings?


290 replies

Badge +2

I just wanted to add a little more info here:
 

I have a C9, Sonos Arc and had the Panasonic 820. While many DTS UHD discs has a core lossy stream (Gladiator plays perfectly fine on my setup for example in lossy DTS 5.1), all releases from Arrow Video don't. Both Donnie Darko and Pitch Black only has a lossless DTS stream, and won't output any audio when playing the discs. The only option is to turn on PCM, but that only gives you 2.0 audio.
 

I returned my 820 and went with the Sony 800m2. Seems like the best option now. Or an Xbox. 

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! 

Userlevel 4
Badge +11

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.

Badge

@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.

Userlevel 1

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.

Userlevel 7
Badge +15

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..

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

Userlevel 1

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..

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?

Userlevel 1

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.

Userlevel 1

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.

Userlevel 1

[...]

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 😀

Userlevel 1

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 ??

 

 

Userlevel 7

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

Reply