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gcsg1
Contributor I
July 25, 2020
Answered

LG C8 and Sonos Arc always showing as stereo 2.0.

Hi, I’ve recently set up my Sonos Arc, I have an LG C8, I know I won’t get true Atmos due to only using the arc port as the C8 doesn’t have earc 

 

i tried Netflix and Disney+ programmes but everything on the Sonos app suggested the Arc is in Stereo 2.0

 

Ive tried changing the TV to Auto and Digital Plus, but neither seem to make a difference 

 

has anyone else experienced this?

 

thanks

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    mpflAnswer
    Lyricist I
    July 30, 2020

    I have an LG C8 with an Arc as well. In the C8 Sound settings you can set the HDMI ARC output to be either Auto or PCM. I’ve found that it will only output Stereo 2.0 when set to PCM. Auto provides a proper surround stream.

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    jthomas009
    July 29, 2020

    @gcsg1

    You are most likely in the same boat as the rest of LG TV owners who bought a Sonos Arc.  What year LG do you have?  You don’t need eARC for DD+ Atmos.  It works also via hdmi arc on LG atmos enabled TVs (year 2017) as DD+ and shows up in the Sonos app as Dolby Atmos.   I have one and it works.  For TrueHD etc you need eArc.   Streaming services are using DD+ according to more knowledgeable posters.

    But I also have a 2020 LG model as do many others with eArc and apparently they have released a firmware update that messes up lpcm and the Sonos arc doesn’t support lpcm yet but it is promised.  There are multiple threads on this. The Sonos Arc lpcm update was also confirmed by a Sonos Moderator that it is in development.

    Sorry it is not better news.

      gcsg1Author
      Contributor I
      July 29, 2020

      Hi thanks for the reply

      Its a 2018 model 

      I'll just have to wait and see what happens then

      I just wanted to make sure it wasn't me orca setting i could change

      Cheers

      controlav
      controlav
      Lead Maestro
      July 29, 2020

      diagnostic, You have the Sonos Arc and no other Sonos devices. As the diagnostic indicated, it is only showing a 2.0 signal being captured since there are no Sonos Sub and Sonos surrounds speakers bonded to it. the Sonos Arc would only be able to interpret a 2.0 signal even if you are watching Dolby Digital 5.1 since there are no other speakers that would interpret the data from the TV.

      I don’t agree with this statement at all. If you feed a 5.1 signal into a Sonos HT device, the system will say it is a 5.1 signal regardless of whether surround speakers are connected or not.

      The usual reason for a 2.0 signal instead of 5.1 is TVs blocking pass-through over optical, which can usually be fixed with an EDID manager.

      Author of the leading independent Sonos apps for Android, MacOS, iOS, Windows and Xbox.
      mpflAnswer
      Lyricist I
      July 30, 2020

      I have an LG C8 with an Arc as well. In the C8 Sound settings you can set the HDMI ARC output to be either Auto or PCM. I’ve found that it will only output Stereo 2.0 when set to PCM. Auto provides a proper surround stream.

        gcsg1Author
        Contributor I
        July 30, 2020

        Hi @Lyricist I

        thanks for the advise, I didn’t realise there was another setting under the HDMI arc, it was set to PCM, so changed it to Auto and it’s fixed the issue

        cheers

          Paul A
          Paul A
          Retired Sonos Staff
          July 30, 2020

          Hi @gcsg1.

          Thanks for the feedback and immediate response.

          We’re glad to hear everything is now working based on your expectation.

          Please do not hesitate to reach out if you still have further questions or concerns. We are always here to help.

          Thanks,

          Help others find useful content by clicking the like button and selecting the best answer to your question
          Harlen
          Lyricist I
          October 20, 2020

          I have an LG C8 with an Arc as well. In the C8 Sound settings you can set the HDMI ARC output to be either Auto or PCM. I’ve found that it will only output Stereo 2.0 when set to PCM. Auto provides a proper surround stream.

          That fixed it on my OLED55C8PTA thanks!  After setting to auto, when viewing in the Sonos app it now says Dolby Atmos is being used. I had actually looked at that setting which was set to PCM but didn’t change it because I thought given there was only one choice it wouldn’t make a difference, but it did. Was also getting very worried the C8 wouldn’t work because I read that LG provided a firmware fix for the C9 and eARC, and there was no mention of C8s.

            Paul A
            Paul A
            Retired Sonos Staff
            October 20, 2020

            Hi @Harlen.

            Welcome to the Sonos community and thanks for your feedback.

            We’re glad to hear everything is now working based on your expectation. I do hope you continue to love and enjoy your Sonos.

            Please do not hesitate to reach out or create a topic if you still have further questions or concerns. We are always here to help.

            Thanks,

            Help others find useful content by clicking the like button and selecting the best answer to your question
            ReDrUm
            Lyricist III
            November 15, 2020

            I just had an issue where my LG OLED E7 which has been working perfectly with my Arc with Atmos (DD+) since I got the Arc, suddenly refused to go higher than DD+ 2.0 from any source (Netflix, Amazon, Disney+, Apple+).

            No idea why, but the solution was to simply reboot the Arc (unplug/replug).

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