PS4 Pro outputting PCM via LG CX shows Multichannel PCM 7.1 for Sonos Arc, but rear surrounds have no audio
I have the Arc, Sub, and Sonos 1 in a surround setup, connected to an LG CX via eArc. Previously I had the PS4 outputting Bitstream (Dolby), and Sonos reported Dolby Digital 5.1.
The fix that added LPCM to Sonos Arc recently went live, so I updated PS4 Pro to output PCM, and the HDMI input on the TV to PCM. (The output remained Passthrough). After doing this, the System Status page for Sonos shows Multichannel PCM 7.1.
However, I now get no rear surround audio in games like Assassin’s Creed Valhalla. (It’s not faint, there’s really none.) I get the full surround experience if I change it back to getting Dolby Digital 5.1. On the PS4 Home screen, I do get sound from the rears in PCM 7.1, albeit very faintly, compared to Dolby Digital 5.1.
Does Sonos not downmix the extra channels properly? It’s kinda bad that a higher fidelity signal sounds worse.
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Hi @billiejoe87
Apologies for any confusion, but Sonos staff get trained in Sonos products, networking troubleshooting and Home Theatre troubleshooting (but only from the perspective of Sonos devices). What we don’t get is training on is the capabilities of all TV models on the market, nor XBox, PlayStation or every other kind of input device’s technical capabilities.
I interpreted the original post as an issue with 7.1 LPCM coming from the PS4, and the experience not being great. As we don’t currently support 7.1 LPCM, I suggested that this is likely to be the problem.
If you have a different kind of stream coming from an input device, and your LG TV converts that to 7.1 LPCM without being asked (and in fact converts all stream types to LPCM) then that clearly has nothing to do with Sonos, and I truly don’t know what you can do to prevent it, other than checking for TV updates and contacting LG if that doesn’t help - we have no internal documentation referring to this issue with help there for me to relay to you.
Once we support 7.1 LPCM on the Arc, I presume that this will no longer be an issue, assuming the TV does what it’s not supposed to do properly.
In the meantime, if you disable eARC on your LG TV, that will prevent it from outputting 7.1 LPCM and instead give you the same feed encapsulated within MAT or DD+, which the Arc will play without issue.
That’s ok @Corry P, I understand you guys are doing your best and appreciate your willingness to help. The issue is the LG OLED is one of the highest selling premium TV’s worldwide, and given the Sonos ARC is a premium sound bar designed for eARC TV’s, it is a big issue. LG Support have unfortunately over the years proven themselves to be beyond useless, so that’s likely why a lot of people are likely hoping Sonos can put pressure on them.
What happens is the LG TV has 2 main eARC modes that send multichannel audio. One is called “Auto” and the other “Passthrough”. It makes sense that a person would use passthrough on the TV to send through exactly what audio a device is sending the TV, through to the Sonos ARC. However this unfortunately results in any LPCM audio being sent as 7.1 regardless of whether it is LPCM 5.1 or 7.1. Other formats such as Dolby Digital and Atmos are unaffected and work properly, other than the Apple TV which seems to send everything other than Atmos as LPCM if it detects a TV or soundbar that supports LPCM.
The main problem with everything being sent as LPCM 7.1 is you end up with quiet audio and sound effects missing or coming from wrong speakers. I have no idea whether LG TV’s are just sending all LPCM audio in an LPCM 7.1 container and since Sonos doesn’t know what to do with LPCM 7.1, the issue is happening.
You can however change your LG to the “Auto” eARC mode I mentioned above which causes the TV to not send LPCM at all while still sending Dolby Digital and Atmos correctly. In this mode, all LPCM content is downconverted to Stereo which means the Sonos processes it properly. Since the Apple TV doesn’t see an LPCM compatible device, it sends audio via Dolby 5.1 and Atmos which comes out correctly. The main issue of course is that for gaming, devices like the Nintendo Switch don’t support Dolby and therefore you are stuck with Stereo. The PS4 and PS5 also have delays with Dolby Digital and many people prefer use LPCM as a result which will also just be in stereo using this mode.
I have chosen the latter “Auto” option personally as I would rather have stereo sound when something sends LPCM, than end up with audio coming out of the wrong channels. It however is an extremely annoying problem to have with high end equipment and one of the reasons I am returning my LG G1 for a Sony A90J as I’m not expecting the Sonos patch to fix it, the way a lot of other users seem to be.
Hi @billiejoe87
Did any Sonos staff link to this thread in relation to the LG TV outputting 7.1 erroneously? If so, please let me know where.
This is a community forum and if community members, or indeed random visitors to the site, mistakenly link this thread as a complete explanation of a different issue, there’s not a lot we can do about it other than to start censoring posts (which we’re not going to do, and could only do here, not in other forums).
As 7.1 LPCM was mentioned here in relation to the Sonos Arc, and the Arc doesn’t currently support 7.1 LPCM, I reported exactly this here - I saw no need to dive any further into the issue. I did not mention LG TVs erroneously converting codecs, nor did I suggest that an update to Sonos would fix it. I simply said 7.1 LPCM is not supported on the Arc, but will be soon. At no point in the original post did the author indicate that the PS4 was outputting 5.1 LPCM while the TV was outputting 7.1. In fact, the author’s second post (first reply) brought up the “downmixing of 7.1 on Arc” subject, which is what I was replying directly to.
In addition, once the Arc does support 7.1 LCPM, I can’t see this being an issue any more - unless LG TVs are not converting to 7.1 properly (which is not something we can reliably determine before the Arc supports it). So, our update may well make the LG issue irrelevant for Arc owners, in which case waiting for the Arc update may actually be the best path forward.
Thank you Corry
Hi @billiejoe87
I certainly can see where the confusion set in. Thanks for bringing it to my attention.
Yes - If I am ever referring to a reply rather than the initial thread, I’ll likely tag the person I’m replying to, and quote their post.
I did start my post with “Hi All” due to the recent activity, but my post was in reference to the initial post. Clearly, saying “Hi All” didn’t help clarify things.
Having said that, I also thought that I was responding to the LG bug posts as well, as our fix should make it irrelevant, as mentioned in my last post.
Hi @ledzep1 & @Shadylane
At present, we have no time scale to share, I’m afraid.
Same problem with
Sonos Beam gen 2
LG G1
we get multichannel 7.1 instead of 5.1 in pass through mode
I’m really bummed to see that technology in 2021 continues to not play nice together. I appreciate sonos trying to solve this problem by offering downmixing but LG should be the ones to blame here imo. I just purchased the C1 and I absolutely love this TV and my arc setup but it’s disheartening seeing this issue.
@Corry P is there any update to this with regard to the feature being worked on? I understand there might not a release window yet but it’d be nice to get confirmation that this is something that is still being worked on, considering more buyers will be picking up TVs like the C1 over the holidays. Thanks.
I have resurrected a few threads on the subjects to keep the possible issue highlighted and to show how poor sonos support has been on giving updated feedback on any progress, they did say they were working/testing this a long while back.
I'm not sure intentionally cross posting on a forum is a very good idea.
So yeah for PS5 it’s showing PCM 5.1 ( not Dolby as I said in my previous post) but can also confirm that Apple TV 4K is still showing 7.1.
I’ve tested 5.1 output on PS5 for about 5 mins, no dropouts on Beam 2 / LG CX, latest software.
TL:DR, it looks like LPCM 7.1 is downmixed incorrectly with side channels coming out the rear and rear channels not coming out at all. Back to Dolby Bitstream it is. (And back to having to switch modes between Atmos and non-Atmos on Apple TV 4k too.) Sigh.
I know Sonos doesn’t do ETAs, but can we at least get an official acknowledgement of this problem?
can you make the PS4 output lpcm 5.?
When I first started the ps5 it was set to “TV sound” lpcm 7.1 and while the number of channels can be changed it was greyed out. I changed the output type to “AV Receiver” and then it let me change the channel to 5.1. After doing that I confirmed in the Sonos app that the Arc was getting “Multichannel 5.1”. After doing this the sound output is correct.
Unfortunately i no longer have a PS4 to test but hopefully it has the same options.
Ive also got a PC and Nintendo Switch. The Switch asked me if I'd like 5.1 or 7.1 so I selected 5.1. The PC was a little tricky, on the PC I can output Lpcm or Atmos but it was defaulting to 7.1.2 or 7.1 for both - I found an option in Windows that let me disabled the SR and LR channel so now the PC outputs 5.1.2 or 5.1 only
For those having issues with the LG CX outputting MultiChannel 7.1 to the Sonos ARC, have you tried changing the sound output to Auto instead of passthrough? This fixed the issue and changed it to Multichannel 5.1 for me.
I have the Arc, Sub, and Sonos 1 in a surround setup, connected to an LG CX via eArc. Previously I had the PS4 outputting Bitstream (Dolby), and Sonos reported Dolby Digital 5.1.
The fix that added LPCM to Sonos Arc recently went live, so I updated PS4 Pro to output PCM, and the HDMI input on the TV to PCM. (The output remained Passthrough). After doing this, the System Status page for Sonos shows Multichannel PCM 7.1.
However, I now get no rear surround audio in games like Assassin’s Creed Valhalla. (It’s not faint, there’s really none.) I get the full surround experience if I change it back to getting Dolby Digital 5.1. On the PS4 Home screen, I do get sound from the rears in PCM 7.1, albeit very faintly, compared to Dolby Digital 5.1.
Does Sonos not downmix the extra channels properly? It’s kinda bad that a higher fidelity signal sounds worse.
It’s counterintuitive but leave the PS4 Pro/PS5 on PCM and change the HDMI Input on the TV to bitstream and the output to Auto. This fixed the issue for me.
For those having issues with the LG CX outputting MultiChannel 7.1 to the Sonos ARC, have you tried changing the sound output to Auto instead of passthrough? This fixed the issue and changed it to Multichannel 5.1 for me.
Changing it to Auto changes the output to Dolby Multi-channel PCM 5.1, which is not the same as Multichannel PCM (LPCM) as far as I know.
For those having issues with the LG CX outputting MultiChannel 7.1 to the Sonos ARC, have you tried changing the sound output to Auto instead of passthrough? This fixed the issue and changed it to Multichannel 5.1 for me.
Changing it to Auto changes the output to Dolby Multi-channel PCM 5.1, which is not the same as Multichannel PCM (LPCM) as far as I know.
It shows in the Sonos App as Multichannel PCM 5.1 when playing Dolby 5.1 content and shows as Dolby Atmos when playing Atmos content (Not DD+ Atmos). From my understanding this is what you would expect to see, since Sonos doesn’t do 7.1.
Ok that is nice, unfortunately not in my case. I’m using an Apple TV 4K and not a PS4 so perhaps there is a difference there. Have to do some more experimenting.
For those having issues with the LG CX outputting MultiChannel 7.1 to the Sonos ARC, have you tried changing the sound output to Auto instead of passthrough? This fixed the issue and changed it to Multichannel 5.1 for me.
Changing it to Auto changes the output to Dolby Multi-channel PCM 5.1, which is not the same as Multichannel PCM (LPCM) as far as I know.
It shows in the Sonos App as Multichannel PCM 5.1 when playing Dolby 5.1 content and shows as Dolby Atmos when playing Atmos content (Not DD+ Atmos). From my understanding this is what you would expect to see, since Sonos doesn’t do 7.1.
Ok that is nice, unfortunately not in my case. I’m using an Apple TV 4K and not a PS4 so perhaps there is a difference there. Have to do some more experimenting.
I’m using an Apple TV 4K as well at the moment on an LG CX and getting these results. I’ve left the Apple TV on Auto, Atmos Available for Audio and I have set HDMI Input Audio on the TV to Bitstream and Audio Output to Auto. It’s really weird how so many of us are getting different results.
Yes extremely weird. What is your source? I’m playing a blu-ray rip with DTS-HD 5.1 with Infuse. But I get the same with all Non-Atmos content from Netflix. I get Atmos with Netflix Atmos content. Below is what I get with audio output on Auto
I am having this same issue on the PS5. I tried selecting the PS5 option of connecting to an AV receiver and using a 5.1 setup but I am still missing audio channels. Anyone know what the exact issue is?
Strange, I need to double check my settings but off the top of my head my LG OLED is set to passthrough and PS5 set to Output Type: AV Amplifier, Audio Type: LPCM, Channel setup: 5.1
Ive also got a PC and Nintendo Switch. The Switch asked me if I'd like 5.1 or 7.1 so I selected 5.1. The PC was a little tricky, on the PC I can output Lpcm or Atmos but it was defaulting to 7.1.2 or 7.1 for both - I found an option in Windows that let me disabled the SR and LR channel so now the PC outputs 5.1.2 or 5.1 only
I’ve seen you mention this, but no-one else (Myself included) has been able to do it. The Nintendo Switch only gives an option for TV Sound Output of Surround, Auto or Stereo. You cannot choose 5.1 or 7.1 on the Switch.
If you somehow know a way, please teach the rest of us.
LG CX and PS5 with Sonos Arc here. I’m using the settings below and getting some pretty solid sound with Dolby Multichannel PCM 5.1. So far any other setting results in Stereo PCM 2.0 and sounds worse. I know it’s not LPCM, but so far I can’t get anything else to work.
LG CX:
HDMI Input Audio Format: Bitstream
Digital Sound Out: Auto
PS5:
Audio Format (Priority): Bitstream (Dolby)
HDMI Device Type: AV Ampoifier
Number of Channels: 5.1ch
Update from Sonos’ CEO on Twitter that they’re working on it:
Brilliant, this fixed along with the drop outs fixed will be all I want for Christmas
I have a different “issue” I’m not sure it’s an issue I never had the LPCM 7.1 but mine always reports 5.1 multichannel on the PS4 and when I turn a character around like in resident evil 2 remake and there’s water dropping it’s coming out from all channels, BUT on the settings on the TV the LG C9 I have the output to Bitstream, if I put to PCM I only get PCM 2.0 on the PS4….it’s weird if my TV is set to bitstream I can set everything to hdmi and PCM on the PS4 and get 5.1 audio I never got any option for 7.1, which is correct, but it changes it to 2.0 if I select PCM on the TV settings no matter if I set it to auto or passthrough I have the same thing
I have a different “issue” I’m not sure it’s an issue I never had the LPCM 7.1 but mine always reports 5.1 multichannel on the PS4 and when I turn a character around like in resident evil 2 remake and there’s water dropping it’s coming out from all channels, BUT on the settings on the TV the LG C9 I have the output to Bitstream, if I put to PCM I only get PCM 2.0 on the PS4….it’s weird if my TV is set to bitstream I can set everything to hdmi and PCM on the PS4 and get 5.1 audio I never got any option for 7.1, which is correct, but it changes it to 2.0 if I select PCM on the TV settings no matter if I set it to auto or passthrough I have the same thing
do you have any other games to test? With water the sound can sometimes come out all around you if that's what the developer intended, especially if the source of water is from a roof/fixture/waterfall that's above your characters head in the game. For example when it's a waterfall like in uncharted 4 you'll notice the sound everywhere if you stand close to the waterfall but if you stand far a enough away you only hear the sound based on your direction to the waterfall
as for bitstream and pcm, use bitstream - as confusing as the names are, pcm is for 2.0 sound and bitstream is for higher quality surround audio
I thought Multichannel PCM or LPCM was the better audio quality and that’s the new codec Sonos supports or maybe LPCM is different….as for the water it was coming specifically from a window and would only play on the channel I was facing that’s how I tested it, and yeah I tested it with horizon zero dawn and the last of us 2 to name a few
Still no LPCM improvement on my CX with the latest 03.21.09 fw gents
Still no LPCM improvement on my CX with the latest 03.21.09 fw gents