PS4 Pro outputting PCM via LG CX shows Multichannel PCM 7.1 for Sonos Arc, but rear surrounds have no audio


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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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I really strongly believe that Sonos is unintentionally misleading us with their supposed fix for this issue.

Sonos will add downconversion for LPCM 7.1 to LPCM 5.1, however I think the issue with LG TV’s incorrectly sending all LPCM audio as LPCM 7.1 won’t be fixed as it’s an LG problem. The LG’s wrongly send all LPCM as LPCM 7.1 even if it’s only LPCM 5.1 audio.

I really hope I’m wrong, but I feel Sonos announcement that the issue was on their own end has made everyone not put pressure on LG to fix their own issue with incorrectly sending the wrong audio. As someone else here said, if you use a HDFury device or a Sony TV the issue goes away.

 

Well said.

 

I have tried contacting LG about the issue but 1st line support don’t seem to grasp what the issue is I’m trying to explain to them, and reply to my emails with some nonsense unrelated to the issue.

This was why I recently asked Sonos support on here if they could help and contact LG to try and get the issue resolved, at the end of the day it might be an LG issue, but sound still comes out a Sonos speaker. 

I find it sad that Sonos seem to wash their hands of issues if it’s not related to their devices, despite that device being in the chain and playing a big part in the actual issue.

Which is why I believe Sonos could help us solve the issue by contacting LG as well to highlight the issue to them with a bit more weight behind it, (being sonos and all).

Is it really asking much for Sonos to contact LG and make them aware of the issue for all LG owners that own the Sonos Arc?

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Hi @billiejoe87 

I really strongly believe that Sonos is unintentionally misleading us with their supposed fix for this issue.

Sonos will add downconversion for LPCM 7.1 to LPCM 5.1, however I think the issue with LG TV’s incorrectly sending all LPCM audio as LPCM 7.1 won’t be fixed as it’s an LG problem. The LG’s wrongly send all LPCM as LPCM 7.1 even if it’s only LPCM 5.1 audio.

I really hope I’m wrong, but I feel Sonos announcement that the issue was on their own end has made everyone not put pressure on LG to fix their own issue with incorrectly sending the wrong audio. As someone else here said, if you use a HDFury device or a Sony TV the issue goes away. 

To be clear, I was addressing the original post, in which PCM was being selected as the output format on the source device.

If your LG TV is converting another format to 7.1 LPCM without being told to, then that is indeed an issue with the TV.

Is it really asking much for Sonos to contact LG and make them aware of the issue for all LG owners that own the Sonos Arc?

No, but it would not count as much as numerous LG TV owners getting in touch and doing the same. If we were to inform them (and perhaps we have already), but there wasn’t a significant volume of LG customers getting in touch with LG about the same issue, they wouldn’t take it as a priority. Customer contact volume is the only thing that will drive them assign the problem with a higher priority. I therefore recommend that you do get in touch with LG.

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Hi @billiejoe87 

I really strongly believe that Sonos is unintentionally misleading us with their supposed fix for this issue.

Sonos will add downconversion for LPCM 7.1 to LPCM 5.1, however I think the issue with LG TV’s incorrectly sending all LPCM audio as LPCM 7.1 won’t be fixed as it’s an LG problem. The LG’s wrongly send all LPCM as LPCM 7.1 even if it’s only LPCM 5.1 audio.

I really hope I’m wrong, but I feel Sonos announcement that the issue was on their own end has made everyone not put pressure on LG to fix their own issue with incorrectly sending the wrong audio. As someone else here said, if you use a HDFury device or a Sony TV the issue goes away. 

To be clear, I was addressing the original post, in which PCM was being selected as the output format on the source device.

If your LG TV is converting another format to 7.1 LPCM without being told to, then that is indeed an issue with the TV.

Is it really asking much for Sonos to contact LG and make them aware of the issue for all LG owners that own the Sonos Arc?

No, but it would not count as much as numerous LG TV owners getting in touch and doing the same. If we were to inform them (and perhaps we have already), but there wasn’t a significant volume of LG customers getting in touch with LG about the same issue, they wouldn’t take it as a priority. Customer contact volume is the only thing that will drive them assign the problem with a higher priority. I therefore recommend that you do get in touch with LG.

 

LG TV’s seem to be sending all LPCM 5.1 content as 7.1.

The easiest way to test this is using a Nintendo Switch which only ever sends 5.1 and seeing the Sonos App still shows 7.1. If you use a Sony TV or HDFury it shows correctly as 5.1.

I understand you guys are busy and doing your best, but you haven’t been clear about these issues, considering LG TV’s are amongst the most popular TV’s out there. Everyone having issues and being told by you guys a fix is coming to down convert 7.1 is going to likely be disappointed when your fix doesn’t do what you guys are promising.

Does anyone at Sonos own an LG OLED from the last couple of years? It would help if you could find out whether it’s a bug on your own or LG’s end, considering I haven’t read a lot about this bug with any other sound bars.

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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.

 

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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.

 

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Hi @billiejoe87 

“Passthrough”, by it’s very definition, is untouched by the device that’s passing the audio through. If this is not what happens (and it really sounds like it isn’t), then I presume there is a coding error in the TV’s interface so the wrong setting is passed to the audio-handling routines, or an error in those routines themselves.

It is unfortunate.

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Hi @billiejoe87 

“Passthrough”, by it’s very definition, is untouched by the device that’s passing the audio through. If this is not what happens (and it really sounds like it isn’t), then I presume there is a coding error in the TV’s interface so the wrong setting is passed to the audio-handling routines, or an error in those routines themselves.

It is unfortunate.

Exactly. I think LG owners need to be aware of this, so they stop expecting the Sonos patch to fix it. I have had an LG CX and G1 which both did this and the reports are universal about it online. The biggest issue is coming from who people expect are going to fix it.

It might help if you guys could communicate that there are 2 different issues here and that your fix will not help issues where the TV is sending 5.1 audio as 7.1.

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Hi @billiejoe87 

I completely get your point, but I cannot communicate an issue that we aren’t officially aware of, especially if the issue is on a partner’s hardware.

Wow this is super discouraging.  Not annoyed with Sonos but with LG for ignoring the issue.

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Hi @billiejoe87 

I completely get your point, but I cannot communicate an issue that we aren’t officially aware of, especially if the issue is on a partner’s hardware.

With all due respect, this issue has been talked about in multiple threads on here and from what I’ve read elsewhere, people were re-directed to this thread. This has led people to believe the fix was coming from Sonos.

Have a look at this thread which is one amongst a few. It discusses exactly what I’m talking about with LG TV’s: 

 

When the 2nd biggest TV maker in the world and manufacturer of the most premium TV’s on the market doesn’t support your product properly, it isn’t going to end well. Especially when there are people all over other forums linking here as evidence it was going to be fixed and who held onto the Sonos ARC’s under the promise there was a fix coming.

 

I think Sonos owe it to the community to get hold of one of these TV’s and work out who’s end the problem is on, as I haven’t seen this same issue with other eARC soundbars and LG TV’s. Or at minimum, make it very clear in this thread (using a stickied post) advising people to contact LG as the issue is not a Sonos one. Something similar to what you guys did with the old LG Lip Sync issue threads.

 

Right now, you are in the unenviable position of potentially accidentally misleading people for months about an upcoming fix for an issue which is unfortunately out of your control to fix, and this thread is what people in many other forums are linking to as evidence that the issue is a Sonos one and not LG.

 

I say this, as I have mentioned in a few forums the issue not being caused by Sonos, and almost always get linked back here to tell me I’m wrong, and you guys are fixing it! LG support have even used it to tell one guy on AVForums that the issue is a Sonos one due to this thread! LG clearly have no intention of fixing anything, as the LG CX which was last years TV suffered with the same issue and still isn’t fixed.

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Hi @billiejoe87 

I really strongly believe that Sonos is unintentionally misleading us with their supposed fix for this issue.

Sonos will add downconversion for LPCM 7.1 to LPCM 5.1, however I think the issue with LG TV’s incorrectly sending all LPCM audio as LPCM 7.1 won’t be fixed as it’s an LG problem. The LG’s wrongly send all LPCM as LPCM 7.1 even if it’s only LPCM 5.1 audio.

I really hope I’m wrong, but I feel Sonos announcement that the issue was on their own end has made everyone not put pressure on LG to fix their own issue with incorrectly sending the wrong audio. As someone else here said, if you use a HDFury device or a Sony TV the issue goes away. 

To be clear, I was addressing the original post, in which PCM was being selected as the output format on the source device.

If your LG TV is converting another format to 7.1 LPCM without being told to, then that is indeed an issue with the TV.

Is it really asking much for Sonos to contact LG and make them aware of the issue for all LG owners that own the Sonos Arc?

No, but it would not count as much as numerous LG TV owners getting in touch and doing the same. If we were to inform them (and perhaps we have already), but there wasn’t a significant volume of LG customers getting in touch with LG about the same issue, they wouldn’t take it as a priority. Customer contact volume is the only thing that will drive them assign the problem with a higher priority. I therefore recommend that you do get in touch with LG.


I agree, but as I said LG 1st line support are beyond useless, I have contacted them numerous times and get some obscure response not at all to do with the issue I told them about, how are we supposed to get it fixed if they don’t have a clue. 
 

That is why I was hoping Sonos would have a better line of contact to LG to help get the issue across.

I understand it’s not really Sonos job to do this though.

It looks like we will just have to live with it.

Crazy as it should be an easy fix I would hope

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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

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Hi @Corry P, I must admit on my quick look over the forum, I can so far only see other users linking here, not Sonos staff.

You however, I believe added to the confusion by posting this earlier in this thread: https://en.community.sonos.com/home-theater-228993/ps4-pro-outputting-pcm-via-lg-cx-shows-multichannel-pcm-7-1-for-sonos-arc-but-rear-surrounds-have-no-audio-6850771?postid=16528488#post16528488

Your post was after a string of messages in this thread including the following 2, along with being almost directly after Ledzep asked for a follow up from Sonos about the problem:

https://en.community.sonos.com/home-theater-228993/ps4-pro-outputting-pcm-via-lg-cx-shows-multichannel-pcm-7-1-for-sonos-arc-but-rear-surrounds-have-no-audio-6850771?postid=16516418#post16516418

https://en.community.sonos.com/home-theater-228993/ps4-pro-outputting-pcm-via-lg-cx-shows-multichannel-pcm-7-1-for-sonos-arc-but-rear-surrounds-have-no-audio-6850771?postid=16516779#post16516779

Hopefully you can see where the confusion set in. As you didn’t quote anyone in particular in your message, I assume now you were replying to the title of the thread, but originally it looked like you were responding to the question about the LG bug.

Let’s hope that like you said, your own update helps with the LG bug anyway. For me I’m moving to the Sony A90J anyway, as I know that works well right now.

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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.

Just so y’all know, my Sony Bravia A80J has the same issue with outputting LPCM 7.1 to the Arc. So this isn’t isolated to LG.. Sony OLEDs use LG panels, but the rest of the TV is almost entirely different hardware. Sounds to me like eARC and the Sonos Arc just don’t cooperate as well as they’re meant to. 

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Just so y’all know, my Sony Bravia A80J has the same issue with outputting LPCM 7.1 to the Arc. So this isn’t isolated to LG.. Sony OLEDs use LG panels, but the rest of the TV is almost entirely different hardware. Sounds to me like eARC and the Sonos Arc just don’t cooperate as well as they’re meant to. 

This is not entirely correct. Use a Nintendo Switch which actually outputs LPCM 5.1 and tell me what you see in the Sonos App when using a Sony TV.

 

The PS5 will output LPCM 7.1 by default, but other devices which actually output 5.1 shouldn’t have the issue with Sony TV’s while they do on LG ones.

Just so y’all know, my Sony Bravia A80J has the same issue with outputting LPCM 7.1 to the Arc. So this isn’t isolated to LG.. Sony OLEDs use LG panels, but the rest of the TV is almost entirely different hardware. Sounds to me like eARC and the Sonos Arc just don’t cooperate as well as they’re meant to. 

This is not entirely correct. Use a Nintendo Switch which actually outputs LPCM 5.1 and tell me what you see in the Sonos App when using a Sony TV.

 

The PS5 will output LPCM 7.1 by default, but other devices which actually output 5.1 shouldn’t have the issue with Sony TV’s while they do on LG ones.

ah, gotcha - so LGs are incorrectly mixing all PCM to 7.1. Sorry for only skimming the thread. Just tested with my Switch and it says “Dolby Digital 5.1”. Regardless, the core problem appears to be with the advertised supported codecs via eARC passthrough on the Arc. I have this issue with LPCM on PS5, and with audio codecs set to auto on my Apple TV. I have to disable automatic codecs and force to DD5.1, which means I get no Atmos! Dunno how the MVP for LPCM didn’t include 7.1 downmixing :(

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Just so y’all know, my Sony Bravia A80J has the same issue with outputting LPCM 7.1 to the Arc. So this isn’t isolated to LG.. Sony OLEDs use LG panels, but the rest of the TV is almost entirely different hardware. Sounds to me like eARC and the Sonos Arc just don’t cooperate as well as they’re meant to. 

This is not entirely correct. Use a Nintendo Switch which actually outputs LPCM 5.1 and tell me what you see in the Sonos App when using a Sony TV.

 

The PS5 will output LPCM 7.1 by default, but other devices which actually output 5.1 shouldn’t have the issue with Sony TV’s while they do on LG ones.

ah, gotcha - so LGs are incorrectly mixing all PCM to 7.1. Sorry for only skimming the thread. Just tested with my Switch and it says “Dolby Digital 5.1”. Regardless, the core problem appears to be with the advertised supported codecs via eARC passthrough on the Arc. I have this issue with LPCM on PS5, and with audio codecs set to auto on my Apple TV. I have to disable automatic codecs and force to DD5.1, which means I get no Atmos! Dunno how the MVP for LPCM didn’t include 7.1 downmixing :(

No worries.

Yeah the Sonos Arc definitely has an issue downgrading actual 7.1 audio to 5.1 which is what Sonos is working on.

LG TV’s however convert all audio including actual 5.1 signals from devices like the Nintendo Switch to 7.1 which is a whole other issue. Hopefully the new fix from Sonos addresses the LG issue as well.

As of right now, I’d be much more confident if I had a Sony TV of the issue being sorted though, as they are just passing through what they are receiving.

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Fix coming when?

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Fix coming when?

Reportedly the July update.

Based on prior software updates, possibly mid-month on a Tuesday.

An update rolled out today for app and speakers, no clue what it does though

With no listed release notes, it would just be bug fixes. 

From reddit:

 

PS5 audio under LPCM is now outputted as Dolby digital plus 5.1 . They fixed the low volume when selecting LPCM LINEAR. Great job Sonos!

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