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Corry P
Corry P
Sonos Staff
April 11, 2022

Please read if you have encountered issues with 7.1 LPCM playback on Sonos via an LG TV

Hi,

We want to gather some details from people experiencing issues with playback of 7.1 LPCM audio streams on a Sonos Arc or Beam (Generation 2), via an LG television set. Specifically, when channels are playing from the wrong speakers - for example, but not limited to, if you hear dialogue only coming from the rear speakers, consistently.

If you have experienced this channel mis-mapping, please provide, in this thread, the following details:

Your LG TV model number

Your media source device name and model number or TV app that the issue was noticed on, and the name of the movie/show that was affected

Models of any other HDMI devices connected to the TV (if applicable)

The confirmation number of a Sonos system diagnostic submitted while the affected media was playing and 7.1 LPCM was reported in the Sonos app.

Thank you for your assistance.

 

 

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    75 replies

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    Corry P
    Corry PAuthor
    Sonos Staff
    January 24, 2024

    Hi @hitmaker77 

    My colleague reported finding the same issue on occasion when testing with the latest revision of Apple TV hardware (Gen 3).

    He mentioned that he found that the easiest way to force a renegotiation between the devices is to disable eARC in the TV’s settings, then re-enable - it should be easier than having to start different media.

    I hope this helps.

    "Common sense is the collection of prejudices acquired by age eighteen." - Albert Einstein
      hitmaker77
      Lyricist III
      January 24, 2024

      Thank you.

       

      So is it a special Apple TV (handshake) problem with no chance of a solution from Sonos side?

       

      It is not a very big problem because it does not happen very often.

      Corry P
      Corry PAuthor
      Sonos Staff
      January 24, 2024

      Hi @hitmaker77 

      It seems that way, yes - if a renegotiation between devices helps, then something went wrong with the negotiation in the first place, presumably. I’ve only heard of such reports from LG owners, however, so it may not wholly be Apple’s issue to address. I really don’t know enough about it to say anything for sure here.

      "Common sense is the collection of prejudices acquired by age eighteen." - Albert Einstein
        RangerDog
        RangerDog
        Producer I
        February 29, 2024

        Solved with money spent!

        So this issue has been annoying me for months since I added the Beam 2 to my system which includes a subwoofer and Play One rear speakers. My TV is an 75” LG 75QNED85AQA and an Apple TV Model A2169, e.g. 2nd generation.

         

        As with many others, Dolby Atmos worked well when included in the media with all the proper check boxes. But reverting to non-Atmos media the Sonos app said Multichannel 7.1 PCM and many sounds, including speech, were muted. My solution was to go back to the Apple settings and change the sound output from “Atmos available” to “Dolby 5.1” which would then work fine but removed Atmos until I again changed the setting. As you can guess, going back and forth with the setting was annoying and sometimes forgotten, but at least it provided satisfactory results when done.

         

        I read in this forum (Sorry to whomever’s idea this was originally but I don’t know the proper attribution.) that the issue was the Apple TV Gen 2 lacking HDMI 2.1 capability, something included in the Gen 3. It seemed to make sense to me.

         

        First I made sure to acquire newer updated and certified HDMI 2.1 cables. Adding them to the Apple TV Gen 2 changed nothing. Then I bought an Apple TV Gen 3. VOILA! Now the Apple TV Gen 3 stays in the “Atmos available” mode and the app tells me (and my ears agree) when the media has 2 channels (Stereo PCM), 5 channels (Multichannel 5.1 PCM) or Atmos (Dolby Atmos).

        With both the ATV Gen 2 and Gen 3 I played quite a bit with the settings. Whether I put the LG TV setting on “pass-through” audio or “auto” the results did not change for any media I played.

         

        Essentially, the fix in my case was to get the newer Apple TV module. (And also being sure my HDMI cables were up to snuff.)

        There does seem to be one bonus: The faster chip in the new ATV improves switching services with differing resolutions. It also seems to produce a better, brighter, clearer image on both lower and high resolution videos. I have no numbers for this but the first time I turned on the TV with everything hooked up, a little “Wow!” was set off in the back of my head. (You know, where the brain interprets the signal from the eyes.)

         

        So I agree with those saying the problem is in the Apple TV and that Apple “fixed” it by offering (at a price) a newer model. Not only did that work for me, it seems pretty typical of how Apple does things. They make great stuff but you gotta pay for it. (Oh, Sonos does that too!)

          hitmaker77
          Lyricist III
          March 1, 2024

          @RangerDog 

           

          I have had these problems with the newest Apple TV.

          But I keep my fingeres crossed that one of the newest Apple TV updates has solved the problem.

           

          I’m not sure, because it has happed to me only one or two times a month.

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