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


Userlevel 7
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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.

 

 


73 replies

Userlevel 7
Badge +18

Hi All,

We feel it’s worth pointing out that, from a technical standpoint, there’s nothing wrong with LG sending a 6 channel stream via an 8 channel mapping - nothing is lost, and all channels appear to be playing from the correct speakers. We don’t view this as a fault that needs to be fixed, just a more unusual choice made by LG in this case.

When Sonos is given the opportunity to do the decoding, however, we will apply a gain boost to increase the volume, which is why DTS or DD will sound louder than LPCM. LG’s converting to LPCM may well be an attempt on their side to homogenise the volumes across various sources and compression types.

In the end, it’s really up to you, the end users, and what you prefer to listen to.

It does seem strange to me that the Passthrough setting on the TV does not seem to actually passthrough - this still might be something you’ll find worth reporting to them.

I hope this clears things up.

Userlevel 3
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It does seem strange to me that the Passthrough setting on the TV does not seem to actually passthrough - this still might be something you’ll find worth reporting to them.

It would be useful if Sonos could also report this to LG as I expect there would be a much higher chance of them actually looking into it and ultimately it would be to your benefit to have this resolved assuming LG TVs default to this behaviour with their new models going forward - less questions and support calls etc.

I’d think the opposite. There’s no financial relationship between the two companies, so I would expect LG to listen more to people who have actually spent money with LG, rather than some random third party providing a competing product to their own sound bars. 

Badge +1

Hi All,

We feel it’s worth pointing out that, from a technical standpoint, there’s nothing wrong with LG sending a 6 channel stream via an 8 channel mapping - nothing is lost, and all channels appear to be playing from the correct speakers. We don’t view this as a fault that needs to be fixed, just a more unusual choice made by LG in this case.

When Sonos is given the opportunity to do the decoding, however, we will apply a gain boost to increase the volume, which is why DTS or DD will sound louder than LPCM. LG’s converting to LPCM may well be an attempt on their side to homogenise the volumes across various sources and compression types.

In the end, it’s really up to you, the end users, and what you prefer to listen to.

It does seem strange to me that the Passthrough setting on the TV does not seem to actually passthrough - this still might be something you’ll find worth reporting to them.

I hope this clears things up.

 

There’s some weird things going on with Passthrough for sure. If I set it to Auto, my Xbox won’t give the options for Uncompressed 5.1 and 7.1. If set to Passthrough, the options are available again.

I’m guessing it’s just best to leave it set to Auto instead of Passthrough if it isn’t doing what it’s supposed to.

LPCM 7.1 and 5.1 with ATV4K and LG TV Mis-directed channels Issue - Revisited

Old thread, but I just recently added rear surrounds (Ikea Bookshelfs) to my LG C1/Sonos Arc SL/ATV4K (2021) set up, and have since had multiple occasions where the sound from the ATV4K 5.1 source (being Prime, Netflix, and AppleTV+) is coming out the wrong channel - the main dialogue comes from the one or the other rear surround instead of the Arc SL). It is intermittent, but does keep happening.  The channel mis-assignment can be “fixed” in the moment by power-cycling (unplugging) the LG TV.  The ATV4K source also consistently shows as “multichannel 7.1” in the Sonos app, when it is of course a 5.1 PCM feed from the ATV.  I have the audio settings for the LG C1 set to “bitstream”, “enable eArc”, and “passthrough” and ATV4K set to “Atmos/Auto”. When the source is from apps on the TV itself, “multichannel 5.1” displays correctly in the Sonos app, and there is no channel mis-assignment.

I know that this is an LG/Apple issue, and not a Sonos issue, but I am raising it here now because @corryp sought evidence of this “wrong channel” behaviour, and it did not appear anyone reading the forum at that time was experiencing it. I took a diagnostic when it happened today (main dialogue from right rear speaker) – watching Netflix via the ATV4k – number 538943573. No need to post “so what is your question?” - i don’t have one - this is fyi for Sonos.

Userlevel 1

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

Badge +1

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

 

Seriously? I have my CX and ATV4K 2nd Gen and of course still have the 7.1 issue on it. If you had the previous version and were getting 7.1, did you happen to notice an audio difference at all now that the new model shows proper 5.1?

I don’t have the misaligned audio issues with my full setup at all.

Userlevel 1

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

 

Seriously? I have my CX and ATV4K 2nd Gen and of course still have the 7.1 issue on it. If you had the previous version and were getting 7.1, did you happen to notice an audio difference at all now that the new model shows proper 5.1?

I don’t have the misaligned audio issues with my full setup at all.

no, I didn't notice any audio difference, simply now the writing on the Sonos app is the right one. 
I had the previous Apple TV (2021) and I too was affected by the 7.1 bug instead of 5.1 read on the app, all resolved with Apple TV(2022)

Badge +1

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

 

Seriously? I have my CX and ATV4K 2nd Gen and of course still have the 7.1 issue on it. If you had the previous version and were getting 7.1, did you happen to notice an audio difference at all now that the new model shows proper 5.1?

I don’t have the misaligned audio issues with my full setup at all.

no, I didn't notice any audio difference, simply now the writing on the Sonos app is the right one. 
I had the previous Apple TV (2021) and I too was affected by the 7.1 bug instead of 5.1 read on the app, all resolved with Apple TV(2022)


Strange, wonder what it’s doing different compared to the previous version.

Userlevel 3
Badge +2

I can confirm, went from 2021 to 2022 model and 5.1 shows correctly. However that now means I get the problem of sound dropouts on MPCM 5.1 signals reported elsewhere in this forum 

Apple tvOS 16.2 didn’t solved the issue and tvOS 22 from LG CS 2022 neither. Happy new year :(

I can confirm, went from 2021 to 2022 model and 5.1 shows correctly. However that now means I get the problem of sound dropouts on MPCM 5.1 signals reported elsewhere in this forum 

Hi, could you do me a small favor and verify something for me? I have the same issues with the 2021 ATV4K (2ndgen) and I’d like to be completely sure the that the 2022 ATV will solve my issues before I upgrade. Could you please play some 5.1 content on your Apple TV and go into the LG settings → general → channels (or whatever the english translation for that menu point is, should be the 3rd under general) → channel search (it’s the 1st menu point in that submenu) and now press “1” on your LG remote for 5 times: this will open the HDMI diagnostics, now navigate to DVI/HDMI status and expand that part, now you will see a new screen with a “general” subsection at the top left corner, here it will now say either PCM 8ch (if it’s still bugged) or (I pray to god) PCM 6ch. Would be really nice if someone with the newest ATV4K and LG CX/C1/CS/C2 could verify this for me (also “passthrough” should be selected in the audio settings instead of “auto”)!

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

 

 

Userlevel 1

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

Apple TV 2022 and LG C1 

passthrough enabled


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…

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


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!

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.

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?

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.

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.

@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.

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.

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

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.

 

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