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ledzep1
Headliner II
November 16, 2020

Dolby 5.1 content outputting as multichannel PCM 7.1 (since LPCM update)

Hi

Thought I would create this thread as a few have reported this issue in the lpcm update threads that are marked as solved so perhaps best to keep it separate.

Issue:

Before the LPCM update last week my sonos arc would receive atmos and Dolby digital 5.1 from the Apple tv 4k box, audio settings were set to the default AUTO-Atmos available.

My LG CX is capable of passing LPCM.

 

Now since the LPCM update with the above settings I still get atmos from apps such as netflix, apple tv + on the apple 4k box, but any content in dolby 5.1 is now outputting as multichannel PCM 7.1, 7.1 being the issue, it should be outputting as multichannel PCM 5.1

 

I have seen similar posts with this issue on the same device and other devices as well.

 

Thank you 

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    Ken_Griffiths
    Ken_Griffiths
    November 19, 2020

    So what happens if you set your TV to DD5.1?

    I have not looked to try, I know there is an auto setting but then that stops me getting full fat atmos from my oppo203.

    Also, have you considered powering off (not standby) the Apple TV4K and the LG TV for a few minutes and then first power-on the TV and set it’s HDMI-2 eARC port to ‘pass-through’ and then power on the Apple TV4K to see if that fixes the issue.

      ledzep1Author
      Headliner II
      November 19, 2020

      ‘ I just would like it to output correctly’

      By ‘it’ do you mean the Arc and by ‘output’ do you mean play?

       

      Yes sorry, I want the ARC to play multichannel pcm 5.1, for me its “outputting multichannel pcm 7.1. 

        ledzep1Author
        Headliner II
        November 19, 2020

        So what happens if you set your TV to DD5.1?

        I have not looked to try, I know there is an auto setting but then that stops me getting full fat atmos from my oppo203.

        Also, have you considered powering off (not standby) the Apple TV4K and the LG TV for a few minutes and then first power-on the TV and set it’s HDMI-2 eARC port to ‘pass-through’ and then power on the Apple TV4K to see if that fixes the issue.

         

        Well I did power it all off the other week, but I will give it a go, although I dont seem to be the only one with this issue, so Im not hopeful it will solve the issue, but thank you for the suggestion.

        Ken_Griffiths
        Ken_Griffiths
        November 19, 2020

        ledzep1,
        I see this in the ‘About my Sonos System’ for the Arc when playing an ATV Netflix DD5.1 source, but it’s an LG C9 TV and an Apple 4HD (not 4K) (just set to ‘Auto’ audio out). So not sure if that is what you’re looking to see as your output/input? I’d expect the ATV 4K to output the same audio, but note I am running the latest ‘public beta’ of Apple’s tvOS software.

         

        John B
        November 19, 2020

        ‘ I just would like it to output correctly’

        By ‘it’ do you mean the Arc and by ‘output’ do you mean play?

         

        Yes sorry, I want the ARC to play multichannel pcm 5.1, for me its “outputting multichannel pcm 7.1. 

        I think it is playing what you are sending it, so the solution is to send it PCM5.1.

        ledzep1Author
        Headliner II
        November 19, 2020

        ledzep1,
        I see this in the ‘About my Sonos System’ for the Arc when playing an ATV Netflix DD5.1 source, but it’s an LG C9 TV and an Apple 4HD (not 4K) (just set to ‘Auto’ audio out). So not sure if that is what you’re looking to see as your output/input? I’d expect the ATV 4K to output the same audio, but note I am running the latest ‘public beta’ of Apple’s tvOS software.

         

        Tried your suggestion still same, in fact I can get multichannel pcm 5.1 if I change my LG cx audio output to AUTO instead of passthrough, but that’s not ideal because I need passthrough for full fat atmos.

        So I think the issue is the cx perhaps , but not sure.

        Ken_Griffiths
        Ken_Griffiths
        November 19, 2020

        ledzep1,


        The A/V source from ATV4 that I was playing to get that audio output shown was a TV series called ‘The Fall’ S01E01, if that also assists?

        John B
        November 19, 2020

        @ledzep1 .  It may be that there is no single set of settings for various sources that will always deliver the format you want to the Arc.  If there is, i suspect it doesn’t involve ‘bitstream’ for the TV audio output.

        The Arc isn’t going to process the audio, it is going to play what you send it (or nothing), IMO.

        Ken_Griffiths
        Ken_Griffiths
        November 19, 2020

        Just to add, my LG HDMI eARC port is definitely set to pass-through - as you can perhaps just make out in the attached screenshot, hopefully?
         

        I would try the ‘powering off’ suggestion,  I mentioned earlier as it might just resolve the handshake. Maybe power off the ARC completely too.

          ledzep1Author
          Headliner II
          November 19, 2020

          Well take the Apple TV 4K for example on auto audio settings it sends atmos where available or LPCM, so any Dolby 5.1 content will play on the arc as multichannel channel pcm 5.1.

          But for me it’s playing as multichannel pcm 7.1 

          I don’t know what else to say really, it’s been said by others as well so I will leave it there and hope someone from Sonos will be able to tell me what the issue is.

           

          @Ken_Griffiths thank you I did try power off, but no luck, it seems to be an issue with cx or later models of LG I think, anyone else with cx have same issue?

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