Multichannel PCM 5.1 dropping out since 14.10 update


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Anyone else experiencing the same issue? Multichannel PCM 5.1 blanks out for a second every 1-2 minutes. I don’t think it’s a bandwidth issue as it works flawlessly with Multichannel PCM 7.1 (thorough test) and Dolby TrueHD Atmos (quick test). And it may have been caused by the Sonos 14.10 update. Setup is PS5→ LG C1→ Beam 2 (via earc).

 

2 weeks ago before the 14.10 update, I watched a bluray film wherein I had my PS5 transcode the DTS-HD MA 5.1 audio to Multichannel PCM 5.1 (as the C1 does not support DTS) and had no issues. Earlier today, I played a bluray film for the first time in 2 weeks and I encountered consistent audio dropouts every 1-2 minutes. It had the same setup where DTS-HD MA 5.1 → Multichannel PCM 5.1. I tested other bluray discs including the one I watched 2 weeks ago and they all now have the same issue.

 

Curiously, I’ve been gaming heavily on my PS5 the past two 2 weeks and haven’t had any audio issues. Then I realized that I’ve been using Multichannel PCM 7.1 when gaming on my PS5. So I made some changes under the PS5 sound settings to make it output Multichannel PCM 5.1 instead. Lo and behold, I am now getting the same consistent dropouts in games and even on the PS5 main menu.

 

I think it’s due to the Sonos 14.10 update as that’s the only firmware update I’ve done in the last 2 weeks. No PS5 update, no LG C1 update. Well actually while I was composing this post, I received and applied the latest LG C1 firmware update and I still have the same issue.


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The dropout duration is almost exactly 1 second, which leaves 38.8 seconds of sound (crudely measured by recording onto my computer). If my assumptions (LPCM signal is 24-bit/channel, a full channel is wasted on LFE) and calculations are correct then probably still co-incidence that this is close to the region of 32MB of data:

2^25 Bytes / 6 channels / 3 bytes / 48KHz = 38.836 seconds

 

 

Support have raised a case. I also decided to time the audio drops, I thought they were random but today I measured them as a regular 39.8 seconds apart.

PCM Multichannel began cutting out again, now on Sonos v14.16 still LG v03.33.11. I tried toggling all the settings I tried previously (I didn’t see “Dolby Multichannel PCM 5.1” this time, only stereo) and disabling CEC on the sources but the drop outs persisted.

I then factory reset the C1, but that did not clear the issue either, so I then generated diagnostic #997513791. 

If you have tried the various things mentioned in this thread and it’s repeatable, then it is suggested earlier by Staff, to get in touch with the Sonos technical support team directly, so they can perhaps look into the matter. I would perhaps give them a call and see if that leads to the issue being resolved with your TV/Devices.

PCM Multichannel began cutting out again, now on Sonos v14.16 still LG v03.33.11. I tried toggling all the settings I tried previously (I didn’t see “Dolby Multichannel PCM 5.1” this time, only stereo) and disabling CEC on the sources but the drop outs persisted.

I then factory reset the C1, but that did not clear the issue either, so I then generated diagnostic #997513791. 

I can confirm that I am having the same issues on my LG C1 Oled with beam gen 2. The only audio file that I have cut outs with is PCM multichannel 5.1, when playing blu rays on my Sony X700 blu ray player. All other formats work fine, including Atmos. Neither Sonos support or LG support have been able to help. Really frustrating as obviously a lot of blu rays have 5.1 tracks on them and I would rather not have to watch them with standard stereo pcm which sounds as bad as the TV speakers. (Hyperbole). 

My 5.1 dropouts seem to have gone, none for at least 12 hours of music/films/games. Sadly I cannot attribute a single setting to the behaviour change. I decided to test removing the (wireless) surrounds  which did not fix the dropouts, so I added them back to the Beam 2. Then

  • Toggled “Sound Mode Share” out of curiosity (as it was mentioned in another thread) - didn’t notice any obvious change
  • Changed “passthrough” to “auto” - this changed the Beam input type from “Multichannel PCM 5.1” to “Dolby Multichannel PCM 5.1” (whatever that’s meant to be - I’m guessing MAT?). This format however had no dropouts for 10 minutes or so, so I flipped back to “passthrough”, but I don’t remember if the dropouts returned at this point :(

my colleague spotted some issues happening on the CEC network and suggests you factory reset your TV

  • Before factory resetting the TV as my next step (it’s not my main TV so not very inconvenient) I thought I’d try manually switching the devices on from standby instead of using CEC.

Then I noticed the dropouts had gone on “Multichannel PCM 5.1”. I then toggled CEC control on the source devices and the drop outs haven’t come back even when using CEC to standby/powerup .

I’ll try to isolate the steps above if the dropouts return, but I can see why the problem is not wide spread, seems to be a temporary state involving the C1/Beam2, possibly cleared by either the auto/passthrough setting or CEC order.

Ah, I see. I didn’t realise multichannel LPCM required eARC.

That hadn’t occurred to me either until I tried it, or that the Amp was just ARC. 

 

I’m a little confused as to how the fault could be with the TV though if it’s set to just passthrough the bitstream?

Presumably the TV shreds the HDMI data stream from the console/bluray and only copies the audio stream to the eARC HDMI port. There’s enough software there for a memory leak or an exception to disrupt the process inside the TV, we know the Beam 2 is reporting the stream drying up. From reading other threads and forums it seems LG have had a difficult time stabilising multichannel LPCM, especially on the 9/X models. Having said that, it doesn’t rule out the Beam provoking the TV into quitting sending data. Would be interesting to know if the diagnostics had shown any kind of handshake during the recovery of the audio drop outs.

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Ah, I see. I didn’t realise multichannel LPCM required eARC.

I’m a little confused as to how the fault could be with the TV though if it’s set to just passthrough the bitstream?

I’m seeing the same issue (Panasonic DP-UB450EB (LPCM) -> LG C1 (eARC) -> Beam2+Symfonisk) when transcoding 5.1 DTS discs in the player. No drops for 7.1 encoded discs. Repeatable switching between 5.1 and 7.1 LPCM on a games console. Occasionally 5.1 LPCM just doesn’t work at all. I tried swapping the Beam for an Amp as per Jay's thread, but of course the Amp is only ARC and therefore no multichannel LPCM to test with.

Frustrating that because LG are being stingy with their codecs (I get it), working around just hits a bug instead. Remains to be proven if this is in LG (v03.33.11) or Sonos (v14.14) or just user error on my part. It’s a narrow use case but it does mean some of my discs will currently only playback (without drops) in down mixed stereo.

Trying to run through this test case though made me think of a couple of gripes where Hifi meets Home Theatre in the same room: 

  • It would be nice to see eARC codecs, some kind of centre speaker configuration and non-Sonance Trueplay on the Amp, which sounded great with standalone speaker frequency range and the wider sound stage.
  • A line in on the soundbars/rears would be convenient for giving legacy components an input into the Sonos ecosystem. Seems odd, expensive and cluttered to need Amp/Speakers or headless port in the same room as a Beam/rears. I understand both the Amp’s and 5’s line in becomes non-operational when configured as rears.  
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@throwawaybeam2 

Yesterday I had finally some time to troubleshoot this. I ended up unplugging the LG to perform a full restart, the PS5 and the Beam2. After that I have been playing with the PS5 for more than one hour with PCM 5.1 as audio output  and I haven’t had a single dropout. Worth trying...

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It seems they fix one thing and break another, I'm looking to replace the Playbar and it's not an ARC straight fight which is unfortunate due to having the Sub etc already.

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I have no issues with my Arc either, but that’s also not connected to an LG TV, I have a Sony TV. I could hook up my Apple TV to the Arcana/Beam, maybe I can reproduce the issue with that but I don’t think so. Unfortunately I don’t have a PS5, if anyone knows where I can get one, let me know 😀. 

I have an Apple TV-4HD with LG C9 TV and Arc, surrounds & sub and it’s set to default - to output 5.1 multichannel LPCM.

I played the movie ‘6 underground’ from Netflix for 30 minutes or so, just as a test …and that’s all working okay without any audio dropouts.

 

What settings do you have set on your c9 for audio?

These are my LG C9 TV Audio Settings…

  • Sound -> HDMI ARC (Digital Sound Out = Pass-Through / eARC = ‘ON’)
  • Sound -> Additional Settings (DTV Audio = Auto) / HDMI input format = Bitstream for all HDMI ports.
  • Connection -> HDMI Device Settings (Auto Device Detection = ‘ON’ / Simplink = ‘ON’ / Auto Power Sync = ‘ON’)
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I have an Apple TV-4HD with LG C9 TV and Arc, surrounds & sub and it’s set to default - to output 5.1 multichannel LPCM.

I played the movie ‘6 underground’ from Netflix for 30 minutes or so, just as a test …and that’s all working okay without any audio dropouts.

 

What settings do you have set on your c9 for audio?

I have an Apple TV-4HD with LG C9 TV and Arc, surrounds & sub and it’s set to default - to output 5.1 multichannel LPCM.

I played the movie ‘6 underground’ from Netflix for 30 minutes or so, just as a test …and that’s all working okay without any audio dropouts.

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My setup is Beam Gen. 2 → HD Fury Arcana and I tested with a Nvidia Shield and Kodi set to Multichannel PCM 5.1 Tested with. several movies and didn’t have any dropouts. Since kikeminchas also has an LG TV and can reproduce it, but ledzep1 can’t (unsure what TV they use), I’m not sure if it’s really the Beam or the LG TV. Maybe some more people will chime in soon. I reckon if this was a broader issue, we will hear soon. 

I use LG CX (latest 4.40.10 firmware) with sonos ARC not had any dropouts, so could be Beam specific.

If those haven't already tried I would do the good old turn it off and on procedure (TV and Soundbar)

Try a different HDMI lead 

Last resort perhaps try a reset on the TV and sonos.

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My setup is Beam Gen. 2 → HD Fury Arcana and I tested with a Nvidia Shield and Kodi set to Multichannel PCM 5.1 Tested with. several movies and didn’t have any dropouts. Since kikeminchas also has an LG TV and can reproduce it, but ledzep1 can’t (unsure what TV they use), I’m not sure if it’s really the Beam or the LG TV. Maybe some more people will chime in soon. I reckon if this was a broader issue, we will hear soon. 

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@Outburst 

As mentioned, I did an update on my LG TV after I have already discovered and replicated the issue. Pre-TV update, the only thing that changed is literally the Sonos 14.10 update. Post-TV update, issue still persists.

It would be helpful to others if you can share your actual setup. So far what appears to be “confirmed” is the audio dropouts occur ONLY on a Sonos Beam 2 running on 14.10 update while it is receiving the “Multichannel PCM 5.1” audio format. 


 

@Corry P

Not trying to be rude but do I really have to go through the extra trouble? You were already able to have a colleague look into my diagnostics multiple times. Can’t you simply pass the info off to your technical team?

While I really do appreciate your efforts so far (and I confess I am unaware of the full scope of your responsibilities), it is disappointing from a customer viewpoint to have someone hold your hand allthroughout only to be let go once you’re about to reach the finish line.

I was already able to narrow it down for Sonos and it is very quick and easy to reproduce. It is 100% reproducible. And with a corroboration from another user, it appears to be a legimitate issue. Even as your colleague tried to deflect the blame on the TV, you have to admit that the Sonos 14.10 update is the most logical culprit. To me, this  seems like something that should warrant the attention of Sonos, even without the prodding of their customers.


 

I may be being dramatic but it is what it is. I believe I’ve done my part as a member of the community. If Sonos does not want to take some initiative, I pass the baton to another troubled Sonos user who is willing to take it from here. I hope it gets fixed in a future update. If not, then this is something to keep in mind. Thank you and goodbye, everyone.

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I have no issues but I don’t have an LG TV. You mentioned an LG update, maybe that’s the reason? It sounds that the update included changes for sound.

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Hi @throwawaybeam2 

As I mentioned, the best way for troubleshooting to move forward is to reset the TV - if this does not resolve the problem, I recommend you get in touch with our technical support team who will create a case for you and be in a better position to assist you, moving forward. 

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 @ledzep1 

Thanks for responding. I assume you’re on Arc and if so then this could be a Beam 2 only as kikeminchas just came forward with the same issue on the Beam 2.


 

@kikeminchas

OMG THANK YOU! I didn’t want to to do a full factory reset on my TV (as per Corry P) but I was desperate enough to re-plug/re-register my HDMI devices and do an AV Reset on the TV. Figured this is as close as I can come to refreshing my AV settings without doing a full factory reset. I actually just finished setting up when I saw your response (spoiler - it didn’t work) so it’s truly a welcome surprise. I suppose the CX’s latest firmware update is perfect timing.

From your inputs, we can infer this is probably an issue with the Beam 2 on the 14.10 update. As I was able to use Multichannel PCM 5.1 with no issues before the 14.10 update. Let’s reach out to the Sonos staff and see if they can dig deeper and confirm the issue.


 

@Corry P 

Hello. As shared above, kikeminchas tested on a PS5 + LG CX + Beam 2 and was easily able to reproduce the Multichannel PCM 5.1 issue. So it’s not an isolated case.

While the sample size is very limited, if we perform a simple process of elimination, it really seems that the Beam 2 on 14.10 is the culprit. kikeminchas tested on a PS5 while I tested not only on a PS5 also a PC. kikeminchas has a CX while I have a C1. Accdg to ledzep1 it works on the Arc and I can confirm that it worked on the Beam 2 prior to the 14.10 update. So all that is left is the Beam 2 running on the 14.10 update.

So again, I would like to ask if Sonos can test for it themselves and confirm if this is indeed an issue or not. This is very easy as in my experience this is reproducible 100% of the time. The engineers don’t even have the wait for very long as the very first dropout occurs with a couple of minutes (and recurs). I have already laid the steps to reproduce the issue. They could test it with a PC which is something they should have on hand.

In my opinion, given that it would literally take 5 minutes for Sonos to test for it, this is the best way to tackle this issue instead of requiring your customer to first perform a factory reset of their TV before moving forward. It is a massive inconvenience, especially if it does not end up solving the issue. I know it’s not exactly what you asked for, but FYI I had just re-plugged/re-registered my HDMI devices and performed an AV Reset on the TV. Figured this is as close as I can come to refreshing my AV settings without actually doing a full factory reset. And issue still remains.

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Hi, Beam2 user here + PS5 + LG CX. I can confirm the dropouts. I was using Dolby in the PS5 until yesterday since selecting PCM would output multichannel 7.1, even when selecting 5.1 in PS5 settings. This was confirmed to be just a LG CX issue mostly and even though supposedly the channels were correctly downmixed I never bothered to use PCM just in case. An update to LG CX couple of days ago fixed this and now selecting 5.1 in PS5 finally shows Multichannel 5.1 in sonos app. However by doing this you get audio dropouts every 1-2 minutes.

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Hi @throwawaybeam2 

 

As per your post in the other thread, Im on 14.10 already and have had my xbox set to uncompressed 5.1 for a while as well, only play games on xbox and have not noticed any dropouts. If I encounter any I will be sure to post here.

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Hi @Corry P 

Really appreciate all the support I’ve received so far even as we’ve not been able to achieve a satisfying conclusion. I am done with this for now as I’ve pretty much spent an entire day working on this. At this point, however, I am of strong belief that this is a weird bug caused by the 14.10 update.

I don’t know if I’m just unlucky or if this is actually an undiscovered issue affecting multiple users as it is not part of the common use case. If one has a Sonos Arc or a Beam 2 connected via earc, then they would most likely be using 1) Stereo or DD+/Atmos formats for streaming apps and 2) LPCM 7.1 or Dolby MAT Atmos for Gaming Console/PC usage. Why would one select 5.1 when they can select 7.1 or Atmos, right?

The only reason I discovered this to begin with is due to a very specific use case where my PS5 (as a bluray player) had to transcode my blurays’ DTS-HD MA 5.1 to LPCM 5.1 so I can enjoy multichannel and lossless playback. Unfortunately, for bluray playback, there is no way to force the PS5 to wrap it in LPCM 7.1 or to transcode to Dolby format instead so I’m guess I’ll be stuck without blurays for awhile. I can only hope that this gets fixed in a future update.

I suppose my final request of you is if you could please get in touch with your technical team and ask them to look once more into it. Even without a PS5, they could very easily test it using a Windows PC (w/c I’m pretty sure they should have) with the steps I’ve outlined above. Should only take 5 minutes to verify. And also, if you could leave the thread open in case somebody experiences the same issue and comes in. Thanks.


 

Hello fellow Beam 2 / Arc users,

Would like to ask for your help verifying if there are audio dropouts with Multichannel PCM 5.1 post Sonos 14.10 update. The weird issue appears to be for the LPCM 5.1 format ONLY! Even LPCM 7.1 works perfectly. 

If you have a PS5 or even a PC, you could try the steps I’ve outlined on my posts above. Just set your device to output 5.1 channels and if there’s indeed an issue, you should encounter an audio cutout within a minute or two. Make sure that your Sonos app reads the incoming audio format as Multichannel PCM 5.1. Thanks.

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Hi @throwawaybeam2 

I don’t disagree - the timing with the update is worthy of note and we did alter some Home Theatre functionality in said update (though I don’t know if any of it pertained to 5.1 PCM specifically and only - it seems unlikely). I’m certain, however, that a reset of the TV is the best way to get the troubleshooting process to move forward, at the very least, given what the engineer I spoke to told me about what was found in the diagnostics.

There is no way to roll-back the software (I don’t like to speak in absolutes because many things are technically possible, but to all intents and purposes it can’t be done).

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