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rubeo
Avid Contributor III
May 6, 2020
Answered

Multichannel PCM on Arc

Are you really not supporting multichannel PCM on the newly announced Arc?

Why? It’s not a licensing issue this time.

It seems like there is always something missing with your home theater products.

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    Ditte
    DitteAnswer
    November 10, 2020

    Hi all,

    We hear you. With a software update today, Arc now supports multi-channel LPCM, bringing new immersive sound experiences for gaming, Blu-ray discs, and more. To get support for multi-channel LPCM on Arc, download the latest Sonos S2 update from the app store and then update your system in the Sonos S2 app. After updating the app, go to Settings > System > System Updates > Check for Updates.

    All the best,

    Ditte

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    mattnunn1985
    Avid Contributor I
    November 12, 2020

    Now the update is out for the Sonos Arc, I want to make sure I’m getting the best audio.

    Playing Atmos content seems to work fantastic now. I am very happy with the sound from the Arc, Sub and 2 Ones.

    When I play videos that have 5.1 audio, my Sonos app reports Multichannel PCM 7.1. Is this a problem as from what I understand my setup is not 7.1 (for reference, I am using an Apple TV 4K, LG GX, Sonos Arc, Sub and 2 Ones)?

    Cheers.

    jesse c
    Contributor I
    November 12, 2020

    The Arc should be down-mixing 7.1 to 5.1 for non-Atmos streams that are actually sending 7.1 channels, and should be following the Atmos instructions for where Atmos streams.
    I’m guessing that most things will have nothing on those side center channels though, so I’d think it should be fine.

      Naekyr
      Enthusiast II
      November 14, 2020

      Ah ok, if you only play games then LPCM is probably the way to go (there might be games with Dolby Atmos, but I’m not a big gamer myself anymore). I think the “let my receiver decode audio” is only for Bluray playback isn’t it? But I would disable that as well, if you only play games. 

       

      Very few games support Atmos, but every game supports LPCM

      SONOS ARC | SONOS Sub | SONOS Play 1 x 2 | LG C9 OLED | PS5 | RTX3090 Gaming PC | Sennheiser GSP600 Headset | Audio Pro T8L Desktop Monitors
      Naekyr
      Enthusiast II
      November 14, 2020

      The Arc should be down-mixing 7.1 to 5.1 for non-Atmos streams that are actually sending 7.1 channels, and should be following the Atmos instructions for where Atmos streams.
      I’m guessing that most things will have nothing on those side center channels though, so I’d think it should be fine.

       

      It’s not - I’ve done some testing and the Arc is currently not downmixing

      SONOS ARC | SONOS Sub | SONOS Play 1 x 2 | LG C9 OLED | PS5 | RTX3090 Gaming PC | Sennheiser GSP600 Headset | Audio Pro T8L Desktop Monitors
        jesse c
        Contributor I
        November 14, 2020

        Well that’s frustrating

        Whistler
        Enthusiast II
        November 14, 2020

        Now the update is out for the Sonos Arc, I want to make sure I’m getting the best audio.

        Playing Atmos content seems to work fantastic now. I am very happy with the sound from the Arc, Sub and 2 Ones.

        When I play videos that have 5.1 audio, my Sonos app reports Multichannel PCM 7.1. Is this a problem as from what I understand my setup is not 7.1 (for reference, I am using an Apple TV 4K, LG GX, Sonos Arc, Sub and 2 Ones)?

        Cheers.

        I have the exact same setup and I am wondering the same. I use Infuse to play Blu-ray rips with DTS-HD streams. Infuse converts the audio to LPCM, but even a DTS-HD 5.1 stream is displayed as Linear PCM 7.1. I noticed the center channel (voice) is playing out of the rears when playing Ed Sheeran Jumping For Goalposts. Maybe something wrong with the channels?

          FishyD
          Lyricist III
          February 9, 2021

           

           

          That’s a negative on the PS5 sadly. If I select LPCM the PS5 will default to 7.1 and will not let me change the channel layout, it’s either Dolby Digital 5.1 or 7.1 LPCM

          On the PS5: settings - sound - Audio Output - HDMI Device Type : AV Amplifier. This is the key setting. It will unlock the ability to set the number of channels to 5.1 and adjust speaker positions. With this setup, I am getting Linear PCM 5.1 with my Sonos 5.1.2 setup. For some reason the PS4 and PS5 interpret an Arc 5.1.2 setup as 7.1. Same number of channels perhaps? 

          FishyD
          Lyricist III
          February 9, 2021

          This is how I’ve got it setup:

           

          LG CX: HDMI in Bitstream (I tried PCM too, makes no difference since the passthrough on the audio out may make this selection irrelevant anyways?). EARC on. Audio Out passthrough.

           

          PS4: HDMI audio. Linear PCM. 
           

          Sonos app reports in getting Multichannel PCM 7.1. However it sounds off. Surround and certain environmental effects are very quiet but certain other sounds like dialogue or gunfire in a game right in front from center channel is very loud. It’s almost like it is missing certain channels or something. I’ve gone back to DD 5.1 which sounds great. Change PS4 output to Bitsream (Dolby) to get DD 5.1 which sounds much better balanced to me with the surround effect. 

          Unless you have a genuine 7.1 setup (now even sure there is such a thing with Sonos) the PS4 is incorrectly identifying your 5.1.2 setup as 7.1 so you have dead spots in your sound field. The same thing happened to me. I swapped to DD on the PS4 and it correctly went to 5.1, like you said. Ran that until I got a PS5. On the PS5 if you set HDMI device type to TV Amplifier, you can force the PS5 to output 5.1 and LPCM sounds great. 

          FishyD
          Lyricist III
          February 9, 2021

          Now the update is out for the Sonos Arc, I want to make sure I’m getting the best audio.

          Playing Atmos content seems to work fantastic now. I am very happy with the sound from the Arc, Sub and 2 Ones.

          When I play videos that have 5.1 audio, my Sonos app reports Multichannel PCM 7.1. Is this a problem as from what I understand my setup is not 7.1 (for reference, I am using an Apple TV 4K, LG GX, Sonos Arc, Sub and 2 Ones)?

          Cheers.

          I have the identical setup except for a Sony tv (HDMI 2.1). With my PS5, I have to manually force it to output 5.1. However, my AppleTV 4K recognized my 5.1.2 setup perfectly; Atmos, 5.1 etc. Download the AppleTV app “Surround Speaker Check” and run through the 5.1 test. Is your Sonos app showing LPCM 5.1? If it’s still showing 7.1, maybe it is the Apple TV? On Apple TV: settings - video and audio - audio format: is change format off and Dolby Atmos on? What video is showing up as 7.1 for you? I’ll test it on my setup. 

          ledzep1
          Headliner II
          February 9, 2021

          The sonos app reporting 7.1 multichannel, I thought was a bug with Sonos ARC?

          All my devices that that should be 5.1 say 7.1 on the sonos app.

           

          My xbox series x,  if set to uncompressed 5.1 outputs as multichannel 7.1 according to sonos app.

          My oppo 203 is exactly the same.

          As is my apple tv 4k for any 5.1 content that it sends as LPCM outputs as 7.1

           

          Is Sonos still working on a fix, thought I read something a while back that they were aware?

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