Skip to main content
majelbstoat
Contributor I
November 14, 2020

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.

    This topic has been closed for further comments. You can use the search bar to find a similar topic, or create a new one by clicking Create Topic at the top of the page.

    127 replies

    Show previous replies
    ledzep1
    Headliner II
    June 14, 2021

    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.

    jackuiowa
    Lyricist III
    June 14, 2021

    Crazy as it should be an easy fix I would hope

    Corry P
    Corry P
    Sonos Staff
    June 14, 2021

    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.

     

    "Common sense is the collection of prejudices acquired by age eighteen." - Albert Einstein
      jackuiowa
      Lyricist III
      June 14, 2021

      Thank you Corry

        billiejoe87
        Chromatic Producer I
        June 14, 2021

        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.

        1 x Arc, 1 x Beam Gen 2, 1 x Amp, 2 x Sonos In Ceiling Speakers, 2 x Sub, 4 x Sonos Ones, 2 x Sonos Era 100, 5 x Symfonisk Lamp (Gen 2)
        Corry P
        Corry P
        Sonos Staff
        June 14, 2021

        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.

        "Common sense is the collection of prejudices acquired by age eighteen." - Albert Einstein
          Kannamathr
          Lyricist I
          June 16, 2021

          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. 

          billiejoe87
          Chromatic Producer I
          June 16, 2021

          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.

          1 x Arc, 1 x Beam Gen 2, 1 x Amp, 2 x Sonos In Ceiling Speakers, 2 x Sub, 4 x Sonos Ones, 2 x Sonos Era 100, 5 x Symfonisk Lamp (Gen 2)
          Kannamathr
          Lyricist I
          June 16, 2021

          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 :(

          billiejoe87
          Chromatic Producer I
          June 16, 2021

          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.

          1 x Arc, 1 x Beam Gen 2, 1 x Amp, 2 x Sonos In Ceiling Speakers, 2 x Sub, 4 x Sonos Ones, 2 x Sonos Era 100, 5 x Symfonisk Lamp (Gen 2)
          Show more replies
          Terms & ConditionsAccessibility statement