Contributor I

Answered

LPCM ETA for Arc?

206 replies
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LG has released a firmware upgrade for the B9/C9/E9 supporting multichannel PCM passthrough. This is great except Arc doesn’t support it yet.

Because of this new update, my Apple TV decides it should use LPCM instead of Dolby Digital 5.1 with Atmos enabled resulting in only 2.0 audio for non Atmos content. The current only workaround is to disable Atmos and enable it when you want to watch an Atmos file. Very frustrating as the previous firmware had no issue.

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DitteAnswer

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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Naekyr

Enthusiast II

After doing a lot of testing on the playstation 5 and my PC, I would suggest you DO NOT use LPCM 7.1

Make sure you force all your devices into LPCM 5.1

If you run 7.1, you will find that the Arc gets mixed up and outputs Surround channels out the wrong speaker or outputs no sound at all

Below I’ve included a visual diagram of this.

If you enable 7.1 LPCM you will find that SR and SL sound is outputted in the RR and RL speakers and the RR and RL sound is not played at all. L, C, R and Sub audio is correct.

Sonos will need to release another update to tell devices that only 5.1 LPCM is available, because some devices just default to 7.1 on the new update and some users may not realise they should change it to 5.1

F

Funkalicious

Lyricist I

I forced my PS5 to output to receiver as 5.1 but I still miss audio channels (Assassins Creed Valhalla is a good test because dialogue disappears if missing channels). Is there anything I need to change on the ARC side?

W

Whistler

Enthusiast II

My setup is Sonos Arc, sub and 2 play:1’s + LG CX + Apple TV 4K. I have the LG set to HDMI bitstream and Passthrough. Apple TV is set to best available. The new Multichannel PCM seems to be working by looking at the About page in the Sonos App, but it shows Multichannel PCM 7.1, while this setup is still 5.1. Should it not show Multichannel PCM 5.1? The results is the channels are not being output from the correct speaker. Using a Surround Channel Test app on the Apple TV shows the channels all wrong, while before it was all good.

N

Naekyr

Enthusiast II

My setup is Sonos Arc, sub and 2 play:1’s + LG CX + Apple TV 4K. I have the LG set to HDMI bitstream and Passthrough. Apple TV is set to best available. The new Multichannel PCM seems to be working by looking at the About page in the Sonos App, but it shows Multichannel PCM 7.1, while this setup is still 5.1. Should it not show Multichannel PCM 5.1? The results is the channels are not being output from the correct speaker. Using a Surround Channel Test app on the Apple TV shows the channels all wrong, while before it was all good.

Yes it should be using 5.1

My guess is that the update Sonos released has a bug or an oversight. I’m sure they’ll update it and after the update one of two things will happen. 1) It will default to 5.1 or 2) It will still show 7.1 and Sonos will implement proper 7.1 to 5.1 downmixing.

I’m leaning towards the 1st option being the more likely outcome

L

ledzep1

Headliner II

Only just noticed this but any Dolby 5.1 content via my Apple TV 4K box is outputting in multichannel pcm 7.1?

Anyone else.

Lg cx setting all set to bitstream/ passthrough eARC on.

N

Naekyr

Enthusiast II

Only just noticed this but any Dolby 5.1 content via my Apple TV 4K box is outputting in multichannel pcm 7.1?

Anyone else.

Lg cx setting all set to bitstream/ passthrough eARC on.

I don’t have an apple box to test, but if there is an option in the settings on the apple box to change the channel configuration to 5.1, then use that. 7.1 does not currently work correctly

This is such a random bug/issue as well. It implies that Sonos somehow never came across this issue during their testing but how lol?

L

ledzep1

Headliner II

Only just noticed this but any Dolby 5.1 content via my Apple TV 4K box is outputting in multichannel pcm 7.1?

Anyone else.

Lg cx setting all set to bitstream/ passthrough eARC on.

I don’t have an apple box to test, but if there is an option in the settings on the apple box to change the channel configuration to 5.1, then use that. 7.1 does not currently work correctly

This is such a random bug/issue as well. It implies that Sonos somehow never came across this issue during their testing but how lol?

Actually just checking Apple audio settings and I have it set as auto/ atmos available and it says audio will be decoded and sent to my equipment as uncompressed multichannel LPCM.

So looks like it’s doing as it should but as you say a bug currently with 7.1 side of things.

Can anyone confirm that Dolby 5.1 on Apple box should be outputting as multichannel LPCM though?

S

ssjken

Trending Lyricist I

My Nintendo switch (on LG CX) is also outputting Multichannel LpCM 7.1 instead of 5.1. However, when I do the test tones, I can still hear all of them correctly. Anyone else running into this as well?

N

Naekyr

Enthusiast II

My Nintendo switch (on LG CX) is also outputting Multichannel LpCM 7.1 instead of 5.1. However, when I do the test tones, I can still hear all of them correctly. Anyone else running into this as well?

you could just change it to 5.1, I have a switch and it can easily be changed if required

L

ledzep1

Headliner II

My setup is Sonos Arc, sub and 2 play:1’s + LG CX + Apple TV 4K. I have the LG set to HDMI bitstream and Passthrough. Apple TV is set to best available. The new Multichannel PCM seems to be working by looking at the About page in the Sonos App, but it shows Multichannel PCM 7.1, while this setup is still 5.1. Should it not show Multichannel PCM 5.1? The results is the channels are not being output from the correct speaker. Using a Surround Channel Test app on the Apple TV shows the channels all wrong, while before it was all good.

Same here all Dolby 5.1 outputs as multichannel pcm 7.1, it should be 5.1, hopefully Sonos release a quick fix.

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