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

Corry P
Userlevel 7
Badge +18

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.

 

 

"Common sense is the collection of prejudices acquired by age eighteen." - Albert Einstein

62 replies

Corry P
Userlevel 7
Badge +18

Hi @exchgr 

Thanks for the update - glad to hear you got things working properly.

"Common sense is the collection of prejudices acquired by age eighteen." - Albert Einstein
E

Just for information, I don't have problems of wrong audio channels, but with lg C1, arc, sub gen 3 and two one as surround the “source also consistently shows as “multichannel 7.1” problem is completely solved with Apple TV 4K 3rd generation (2022) in fact now always shows "multichannel 5.1" when the track is in that format

Confirming that upgrading from a 2nd gen to a 3rd gen Apple TV 4K fixed all my multichannel PCM 7.1 mapping issues. Now the Sonos app shows multichannel PCM 5.1 for 5.1 content, and everything is mapped correctly. So this issue definitely lies with the 2nd gen Apple TV 4K. Since the two generations run the same tvOS, I’m assuming this is a hardware issue in the 2nd gen.

G

I started having problems with sound playing from the wrong channel sometime over the summer.  Have LG G2 (latest firmware), Apple TV(latest os), xbox - and sonos arc, sonsos one and sub.  It seems to happen quite often after using the apple tv youtube app - not sure if that means anything - or maybe it is just noticed more due to watching lots of youtube, heh (doesn’t happen in youtube, but seems to trigger it in other apps like plex, netflix, etc).’

Anyway, I tried the fix listed here - setting the digital audio from ‘auto’ to ‘pass through’ and that seems to have fixed the problem, so thanks!

 

Corry P
Userlevel 7
Badge +18

Hi @exchgr 

Thanks! I don’t know if yours is quite the situation my colleague was looking for when he asked me to open this thread, but I will pass your report over to him nonetheless - it’s fairly close!

"Common sense is the collection of prejudices acquired by age eighteen." - Albert Einstein
E

This is a Sonos community board. I’d be terribly surprised if any developers, including Sonos developers, are ‘lurking’. 

I am happy, however, as an owner of several Apple TVs myself, that you’ve reported the issue to Apple,

Corry P works for Sonos and specifically solicited this feedback from the community in the original post.

Airgetlam

This is a Sonos community board. I’d be terribly surprised if any developers, including Sonos developers, are ‘lurking’. 

I am happy, however, as an owner of several Apple TVs myself, that you’ve reported the issue to Apple,

Bruce
E

Speaking to the original question, I do have problems with mismapped channels. I think I’ve narrowed the issue down to the Apple TV 4K 2021. It’s the only source device experiencing the issue. The issue is that each front channel seems to come out of all front speakers at the same time, and each rear channel seems to come out of both rear speakers at the same time. I’ve also submitted this issue to Apple, FB13404270, in case any Apple devs are lurking. Since this only seems to happen with Apple TV, I don't think it’s a problem with Sonos, but I’m posting here just in case.

My setup:

Apple TV 4k 2021 → HDMI → LG CX 55” → HDMI eARC → Sonos Beam Gen 2 + 2x One SL as 5.0 surround

Configuration:

Apple TV:
Audio Output: Receiver Speakers
Audio Format: Auto, Atmos Available (Change Format: Off)
Audio Mode: Auto

LG CX:
Sound Out: HDMI ARC
HDMI Input Audio Format: Bitstream
Digital Sound Out: Pass Through
eARC: on

---

Your LG TV model number: LG CX 55”

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: Apple TV 4K 2021, Netflix Test Patterns: https://www.netflix.com/watch/80164785 (see here to show it in the Apple TV Netflix app: https://www.tomsguide.com/how-to/how-to-use-the-netflix-test-screens)

Models of any other HDMI devices connected to the TV (if applicable): Nintendo Switch, PS5, which are off during testing but independently map channels correctly

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.: 2109599949

Corry P
Userlevel 7
Badge +18

Hi @JakeG 

There seems to be a discrepancy between the format reported and the format actually being delivered.

We can see that it is because of this that the channels are getting downmixed to the incorrect outputs. That's why FC (Front Centre) and LFE (Sub/Low Frequency Effect) get rendered to RRC (Rear Right Channel) and RLC (Rear Left Channel) (which we downmix to LS/RS) resulting in the dialogue coming from the surrounds.

So if the Apple TV sends 7.1 MPCM, and the TV isn't passing it through correctly (some kind of mapping bug), it comes out of the LG signalled as 7.1 but it's only 6 channels instead of 8, and in the wrong order.

We believe using the following settings will fix things for you, as they have worked in our own (limited) testing:

I hope this helps.

"Common sense is the collection of prejudices acquired by age eighteen." - Albert Einstein
Corry P
Userlevel 7
Badge +18

Hi @JakeG 

Thanks for that report - I have passed the details to a colleague.

"Common sense is the collection of prejudices acquired by age eighteen." - Albert Einstein
J

LG C2 2022

Netflix via Apple TV 4K (first gen)

Sex Education: S2E7

Apple TV into HDMI 1, HDMI 2 eARC out into Beam Gen2

Diagnostic: 2018107307

issue: front and rear channels swapped in playback

Corry P
Userlevel 7
Badge +18

Hi @MJW75 

It’s a different issue, but not one that you should have to put up with.

The next time this happens, please submit a support diagnostic while it is happening and before trying to fix it. Once complete, record the number given then do what you need to do to resolve the issue. Then, when convenient, I recommend you get in touch with our technical support team who have tools at their disposal that will allow them to give you advice specific to your Sonos system and what it reports - give them the diagnostic number and they will be able to see what was happening at the time.

I hope this helps.

"Common sense is the collection of prejudices acquired by age eighteen." - Albert Einstein
M
Userlevel 3
Badge +1

I’m not sure if this is the same thing. I have a Beam Gen 2 and a Sub Mini running off a ATV 4k 3rd Gen and an LG C2. Sometimes the Beam will play surround channels only with no centre (vocals). I usually need to reboot everything to get it working again. This isn’t just with 7.1 audio though. 

Airgetlam

Unfortunately, that data you’ve provided doesn’t really help track the issue. What you should do is submit a system diagnostic within 10 minutes of experiencing this problem, and call Sonos Support to discuss it.

There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution.

When you speak directly to the phone folks, they have tools at their disposal that will allow them to give you advice specific to your Sonos system and network.

 

Bruce
M

Hi, fairly new to the Sonos experience here. I have an issue similar to what you mention. Channels occasionally swap, often center channel swaps to rear. Sometimes no sound at all. This usually occurs when a new signal is “introduced” - if I change TV channel, change Netflix or Hulu programs or even sometimes when a commercial pops on. It’s resolvable by backing out of whatever I’m watching, switching to something else, then going back. I’d say this happens 20-25% of the time, which doesn’t sound like a lot, but it’s pretty annoying. 
Anyway, here’s my setup:

LG G2 65”

AppleTV 4K

Sonos Arc, Sub, 2 surrounds. 
 

thanks,

Dave

Corry P
Userlevel 7
Badge +18

Hi @ajdz859 

I created this topic over a year ago to determine once and for all whether anyone was experiencing channel mis-mapping or not, as there had been some inconclusive chat at the time. No-one reported having the issue at the time, and as with all discussions here on the community forum, it was in reference to the mainline software version only. It seems there was no such issue, so there was nothing to resolve.

However, your mention of Beta was a red flag - not only is all discussion of Beta banned from this forum, it being a direct contravention of the agreement you made when signing up to the Beta programme, but you are using software that essentially wasn’t asked about - Beta software is expected to be different. So, while your subject may seem on-topic for this thread, the fact that you are using Beta software makes you off-topic for this entire site, which overrules you being on-topic for this thread.

I do realise I came in rather heavy-handed in replying to you, but I stand by my wanting to immediately emphasise that discussion of Beta is not permitted here. So, apologies for any offense taken at my tone, but I was trying to protect you from being censored and possibly barred from the site - depending on what you said next.

I hope this clears it up.

"Common sense is the collection of prejudices acquired by age eighteen." - Albert Einstein
A

@Corry P your response is confusing and frankly, unnecessarily dismissive of the relevant topic of THIS thread. Are you suggesting that the LG TV issue is resolved? Your initial feedback point is well taken, but overlooks that I have pointed out that I'm experiencing the sound channel mapping issue which is on topic for this thread.

Corry P
Userlevel 7
Badge +18

Hi @ajdz859 

Not only is Beta software irrelevant to any discussions here on the forum, it is also against the forum rules. Please don’t discuss Beta experiences here.

It’s clearly not something you want happening, however, so I recommend you feed this back to the Beta team - though it sounds like you have already. Thanks.

"Common sense is the collection of prejudices acquired by age eighteen." - Albert Einstein
A

I experience this. I'm also in a beta software test now so this is cross-posted there.

 

1. Watching a series of episodes (Netflix and Amazon prime video, sometimes the audio for a new episode plays from wrong channel. Dialog from rear right, back left has background music, arc sound bar has traditionally surround audio.
2. Stopping episode and then resuming fixes the mix
3.
4.

Tell us what happened:
tv model LG OLED65C2AUA
Watching via apple tv 4k
Sonos arc connected via eARC
Experienced watching episodes of "I think you should leave" on Netflix and "Oh Cook!" On Amazon.

S
Userlevel 1
Badge +1


It’s definitely 6 CH, just checked;

 

GENERAL

HDMI3, HPD: HIGH, 5V : HIGH, R×Sense : HIGH 3840×2160P @ 23.97Hz RGB 8BIT NODATA PCM 6Ch 48000HZ

HDMI Mode : HDMI, HDR Type : SDR

 

 

Than you both very much! This has plagued me for so long now that I’m willing to spend the money and just buy a new Apple TV…

Just beware of the sound drops with 5.1 signals if you have a beam

Thanks for the heads up, we have a Sonos Arc 5.1 Setup, I hope everything will be fine!

 

Did you end up upgrading after all?

L
Userlevel 5
Badge +11


It’s definitely 6 CH, just checked;

 

GENERAL

HDMI3, HPD: HIGH, 5V : HIGH, R×Sense : HIGH 3840×2160P @ 23.97Hz RGB 8BIT NODATA PCM 6Ch 48000HZ

HDMI Mode : HDMI, HDR Type : SDR

 

 

Than you both very much! This has plagued me for so long now that I’m willing to spend the money and just buy a new Apple TV…

 

Hi

May are ask what your issue was?

I have multichannel pcm 7.1 via my 2021 Apple TV as well, but never found it to be an issue, I do get multichannel pcm 5.1 via my PS5, so it seems to be device dependent.

Do you just want a new 2022 Apple TV so it displays 5.1 correctly or is there an actual sound issue?

 

I thought this one got put to bed a while ago and there was any sound issues as such.

B


It’s definitely 6 CH, just checked;

 

GENERAL

HDMI3, HPD: HIGH, 5V : HIGH, R×Sense : HIGH 3840×2160P @ 23.97Hz RGB 8BIT NODATA PCM 6Ch 48000HZ

HDMI Mode : HDMI, HDR Type : SDR

 

 

Than you both very much! This has plagued me for so long now that I’m willing to spend the money and just buy a new Apple TV…

Just beware of the sound drops with 5.1 signals if you have a beam

Thanks for the heads up, we have a Sonos Arc 5.1 Setup, I hope everything will be fine!

S
Userlevel 3
Badge +2


It’s definitely 6 CH, just checked;

 

GENERAL

HDMI3, HPD: HIGH, 5V : HIGH, R×Sense : HIGH 3840×2160P @ 23.97Hz RGB 8BIT NODATA PCM 6Ch 48000HZ

HDMI Mode : HDMI, HDR Type : SDR

 

 

Than you both very much! This has plagued me for so long now that I’m willing to spend the money and just buy a new Apple TV…

Just beware of the sound drops with 5.1 signals if you have a beam

B


It’s definitely 6 CH, just checked;

 

GENERAL

HDMI3, HPD: HIGH, 5V : HIGH, R×Sense : HIGH 3840×2160P @ 23.97Hz RGB 8BIT NODATA PCM 6Ch 48000HZ

HDMI Mode : HDMI, HDR Type : SDR

 

 

Than you both very much! This has plagued me for so long now that I’m willing to spend the money and just buy a new Apple TV…

E
Userlevel 1

I also just checked and it says pcm 6Ch 48000Hz
 

Apple TV 2022 and LG C1 

passthrough enabled

S
Userlevel 3
Badge +2


It’s definitely 6 CH, just checked;

 

GENERAL

HDMI3, HPD: HIGH, 5V : HIGH, R×Sense : HIGH 3840×2160P @ 23.97Hz RGB 8BIT NODATA PCM 6Ch 48000HZ

HDMI Mode : HDMI, HDR Type : SDR

 

 

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