Multichannel PCM 5.1 dropping out since 14.10 update

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Maybe try using an audio extractor instead and bypass the LG TV altogether. Here are some ‘example’ extractors I’ve seen mentioned in the community here and elsewhere, but I do suggest you research them before any decision to purchase.

I can’t see any reason why such devices would not solve your issue. I actually use one myself on a TV that has no eARC port.

HDFury Arcana

Feintech VAX04101 (I have this device)

OREI HDA-931 or OREI HDA-935



Thank you for the links I will do some reading on these products. Not sure if using one of these will affect the performance of my game consoles for example, HDMI 2.1 features.


I recently purchased the optical HDMI cable that @MJW75 suggested in a previous post. It works perfectly, I have had no dropouts in the last week so definitely recommend anyone with this issue to use this cable. 

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For those that aren’t aware, I posted a work around a few months back. Everyone who has reported trying it has confirmed it works. I’ve not had an issue since doing this. 

You need a one way optical HDMI 2.1 cable between the Beam and the TV with the TV at the source end of the cable. This will stop the drop outs. CEC will still work. The only missing feature are the images (screen saver?) sent from the Beam to the TV - which is a pointless feature anyway. These cables are not expensive. The one I bought from Amazon UK was £17 (about $20). If you want more info, read from my post on page 11 onwards. 

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Beam 2, One, and Sub 3 with LG CX

I feel like we can't narrow down what hardware is causing this issue. It could be Sonos or LG.

If I remember the posts on this thread correctly, on the Sonos side it seems limited to Beam 2 reporting issues with the C1, and now CX. Several users have reported no issues with the Sonos Arc (it’s a frustrating name to search amongst ARC, eARC and Arcana...).

Does anyone have an eArc soundbar from another manufacturer they could test with 5.1 pcm?

I may be able to run a brief test on an eARC enabled AVR soon, although if I don’t hear the dropouts that won’t prove much.

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So after an inordinate amount of time and effort trying to solve this I think I might have fixed it with…a new HDMI cable

after trying every variation of settings, resets, earc on/off, and cable testing through the Apple TV (which reported no issue) I tested my PS5 with 5.1 (as reported it defaults to 7.1 in soundbar mode and this worked fine) and did not have the same issue. I then swapped the cables between PS5 and ATV and seemingly no more dropouts on the ATV.

I’m absolutely baffled how the cable can carry Atmos, 7.1 fine but couldn’t do 5.1 - I wonder if a certain pin in the cable is in use that otherwise isn’t with other sound formats?


I need to keep testing as it may come back but for now I wanted to let people know in case I can save them the same frustration I’ve had the last few weeks.



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Ok let's say mixed results.  Got the cable all hooked up and then popped a disk in that I knew I had the issue with.  Sonos app shows multi channel 5.1 pcm and seemed to play ok, no sound drops. Then we've watched netflix, 4k Atmos and that played fine which was expected.  Now we went back to watching the disk again and there was no sound at all from the main film.  The menu had background music but nothing when watching the film.  Did a full power off and back on and managed to get some sound but now Sonos is only saying stereo pcm.   Confused 

I believe this is a different issue. I get this too occasionally - always after switching HDMI input.

Anyone else get this?

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A1 and C1 are set to passthrough. Beam 2 will accept “Dolby Multichannel LPCM 5.1” if set to auto, but I think this is the PCM in MAT (bridged by the TV) so not triggering the dropouts either.

This is because setting it to “Auto” in effect limits the TV. It becomes like the Optical/ARC TVs of old where it can only receive Stereo PCM and uses Dolby for multichannel. Stereo PCM is outputted as such however the TV unpacks AC3 and repacks it into Dolby PCM 5.1 before sending to the soundbar.

With “Auto”, I’m guessing the Apple recognizes that the TV cannot do multichannel PCM so the Apple already sends audio as DD/AC3 even if you had set “change audio format” to off. Tested this before with a PS5 where using DD output results to Dolby PCM 5.1 while all PCM formats (2.0, 5.1, 7.1) only result to PCM 2.0. So sadly this can’t be used as a workaround. Just set to / test for “Passthrough”.


Why the hell are we trying to do Sonos’ work for them here?

Totally agree. Haven’t troubleshot this issue for a long time just sharing my previous findings. But I’m not exactly being altruistic. If an industrious user wants to find a fix / workaround, I’ll benefit as well. Or if this thread can increase awareness and complaints, maybe Sonos will finally get off their lazy bum.

Edit: That said, I’ve said all I wanted to say and shared everything I could. So I’ll probably go back to lurking while waiting for a good deal on a Beam replacement lol.

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Just got a beam (gen 2) and two one Sl. 

Having this exact issue when Audio is set to (5.1) on ps5 and Nintendo switch. 

Very frustrating after spending 600 on a new set up. 

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Does it stay like this on hdmi 3 / 4 after power cycling?
What happens if you change back the cable? And then back again?

I doubt it’s the cable because I’ve tried multiple cables and all had these problems.

Did you try a one way optical HDMI cable?

Leaving the optical HDMI cable installed and the Apple TV on HDMI 3, I power cycled everything. Tested for 30 mins (I know that isn’t long), but no issues. I power cycled everything again leaving everything off for 10 mins. It still worked when it powered back on.

I then power cycled again and changed to the original supplied Sonos HDMI cable between the TV and Beam Gen 2. The issue came back straight away. Power cycled again and the issue is still there.

I just put the optical cable back in and it seems to work again.

I’ll concede that it could be something else, but what I can say is that in my testing it consistently doesn’t work with the regular HDMI cable and consistently does work with the optical HDMI cable. I’ll keep the optical cable plugged in and the Apple TV on HDMI 3 and will update here in a few more days.

If anyone with this issue has a one way optical HDMI cable, please can you try and replicate my findings. Alternatively, they can be bought relatively cheaply on Amazon.

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Same problem here…

Beam Gen2, Sub Mini, 2 x One SL
HDMI 1: Apple TV (Gen2)
HDMI 2: Beam 
HDMI 3: PS5 (currently set to 7.1., for no dropouts…)
HDMI 4: Switch (annoying dropouts… sometimes even NO sound)

My Apple TV is connected with an HDMI CEC Blocker. But i am using mostly the TV Apps. 
Playing around with connections and power cycles and suddenly it was working.
PCM 5.1 was running without issues for about 6-7 weeks.

After a Sonos Update dropouts again…
Trying around with power cycles, Ethernet/wifi connections, settings and unplugged HDMI 1.
Working again with no dropouts.

Sonos Update yesterday… Dropouts…

HDMI 1 has the same dropouts! Not only HDMI 3/4.
In the Sonos App „PCM 5.1.“ is disappearing for very short moment when the dropout accurs. 

Only stable but not acceptable „workaround“: don`t use Apple TV, PS5 7.1 Mode, Switch Stereo Mode.

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Just got a beam (gen 2) and two one Sl. 

Having this exact issue when Audio is set to (5.1) on ps5 and Nintendo switch. 

Very frustrating after spending 600 on a new set up. 


Yeah it’s unfortunate and very frustrating. Over the past few months I tried replacing it with other soundbar systems, and while one or two did sound better that included a sub at a similar price, they all dealt with there own issues. Ones that I found more egregious than this hiccup the Sonos has.

The only other bug I’ve experienced with the Beam over 2 years was playing Resistance: Fall of Man on PS3, terrible audio distortion for some reason (I tested on other systems and they didn’t have this issue with the game). Otherwise it’s great. I do eventually want to replace this system with a full on receiver and dedicated speakers.

I don’t like recommending stepping up to the ARC to avoid this issue because I really believe Sonos should fix this on the Beam, but I’d consider if I were you. Otherwise if you want to go all out, build your own system with a receiver! :)

The Beam is overall really good for a soundbar. They NEED to fix this issue but hopefully you can use HDMI port 1 or the cable workaround discussed a few comments above here if you decide to stick with the Beam.

Yeah, this is also a matter of trust. It’s difficult to recommend spending more money on Sonos after the level of neglect that they’ve shown here. Say you upgrade to an Arc (or Arc 2/Beam 3) and you encounter an issue particular to your use case, what then? Things could even work well at first, but we are just a bad firmware update away from being screwed. Sonos needs to demonstrate that they will not abandon their customers.

I suggest going for a full refund if you can. If not or if you’re into the Sonos ecosystem, use the HDMI 1 or cable workaround as suggested. We are nearing the 1 year anniversary of this thread and still no official response from Sonos.

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Beam 2 + LG G2 + PS5. Exact same issue with the audio dropping every few seconds, only when PS5 is set to AV Amplifier 5.1 LPCM.

After so many people here complained on the exact same issue I really don’t understand why Sonos is having such a hard time replicating it. All it takes is an LG TV and a Beam 2 with some 5.1 LPCM track.

This wasn’t an issue with my LG C9 btw. Seems like Sonos doesn’t like LG and LG doesn’t like Sonos back.

Ok so, it seems like, hopefully, I managed to fix the problem. I disabled “QuickStart+” in the TV menu, played around back and forth with some of the audio settings for a few minutes (bitstream->pcm and back, passthrough->auto and back, eARC on and off etc. multiple times) then set my PS5 to AV amplifier mode with 5.1 channels and while leaving it on and browsing the web for more info on the problem I noticed that there are no more drops in the sound (the PS5 was on the sound menu for some 15 minutes while it was idle). I found it odd so I went ahead and played a game for several hours, making sure it’s on 5.1 channels mode with LPCM, and there were no more sound drops. I then also noticed that I was not using the Sonos hdmi cable provided with the soundbar but some generic hdmi cable (because the Sonos one was too short). I went ahead and tried replacing it with the Sonos cable just for good measure as I’ve read it’s higher quality. Since then several days have passed and I’ve had no more drops. I don’t know if QuickStart+ was the culprit, or fiddling around with the settings helped, or perhaps it was even the cable, so I know it sounds a little bit like voodoo, but all of these steps together fixed the problem for me, at least so far.

Might be worth a shot for you guys too! Let me know if it helped anyone.

This this!! Thank you! I turned off QuckiStart+ and no more drop out is pcm 5.1 I tested the apple tv nintendo switch and PS5 multiple hours with games movies and tv shows

I had to look up what QuickStart+ even was, but I can see how this might be cause, possible apps running in the background trying to take control of the audio output stream at regular intervals, but they only understand 5.1, so don’t impact an HDMI 7.1 stream? Reboots/setting changes may force some background apps to stop, and exhibiting different behaviour?

Also, if owners are switching off QS+ for other reasons, might explain the reduced number of reports of this problem.

However, I just checked and my QS+ was already disabled even though I hear the dropouts...

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When I’m on my ps5 and audio is playing, I turn on my Apple TV (without switching to its source) and the moment it turns on, the audio cuts, just as it does regularly. It returns moments later.

I can repeat this behaviour, as you say it does sound exactly like the regular audio drops. I pulled the power on the ATV a few seconds after the PCM 5.1 dropped on the active HDMI port. There were 3  short audio drops whilst the ATV booted and then the next scheduled dropped occurred at 59 seconds. I’ll try with the A1 next time I have access to the HDMI ports.

Also, I managed to trap the bug into a single HDMI port. Further to observing the PS5 was bugged and the ATV wasn’t, I then repeatedly swapped the HDMI cables between ports 1 and 3 at the TV end. It didn’t matter which device was playing on port 3, it was the bugged one. HDMI 1 also continued without dropouts, regardless if the source device was PS5 or the apple TV. Suggests the C1 isn’t blameless?

C1 firmware updated to 3.34.70, no change in audio drops. 

I also sacrificed a “high speed with ethernet” HDMI cable and cut what I think is pin 13 (CEC), but whilst the HDMI 2 video is intact, and I’m now able to de-activate CEC (the remote also stays working), the TV doesn’t engage either eARC or ARC and audio is limited to the TV speaker. I cut the red wire - maybe I should have cut blue 😬

What you’re saying is interesting. For me the ATV is on HDMI 1 and I don’t have sound drops (although it’s usually playing Atmos or stereo content), and the Switch is on HDMI 3 and the PS5 on HDMI 4.

Perhaps it’s HDMI 3 and 4 only which are bugged…

Anyway it’s looking like something with some kind of device polling every 59 seconds.

The problem has always been my ATV on HDMI3, the PS5 on HDMI1 is fine. I had previously moved the ATV to HDMI4 but that never fixed it.

Perhaps the HDMI sockets are split into 2 banks somehow with the Beam being on the HDMI 1 and 2 ‘bank’ due to ARC being HDMI2? Then perhaps it is some kind of interrupt from the 3/4 bank that is causing the issue? I still can’t work out why the Arc would be unaffected though

This is my best guess as well.

It has gotten noticeably worse since the last few updates too.

I bought the cable from amazon singapore and will be testing as well.

One of the previous posts mentioned this issue occurs particularly when the device is connected to either of ports 3 or 4 on the back on a LG C2/G2. 


I tried using post 1 with my Nintendo Switch set to ‘surround sound’ (LPCM5.1) and it seemed to work for at least half an hour. 


Has anyone else had a similar experience to this with other LPCM5.1 devices?


I’m curious about whether I need the cable or need to just permanently switch the inputs. Also if anyone know what might be special about ports 1 & 2 on an LGC2 TV that would be useful (considering all 4 ports are labelled as 4k 120Hz HDMI 2.1 ports).

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I read somewhere that some features are still bi-directional on optical HDMI but thought I’d try it anyway. I can’t explain why it is working for me and not you. Just to check - you put the cable between the TV and Beam right, with the TV at the source end of the cable? Not between the source and the TV. 

I had the source end of the optical cable on the beam, other end in TV HDMI2. So I swapped the ends over (source in TV HDMI2 other into the Beam) and so there was no Sonos video displayed on HDMI2 (as now the cable is in reverse) however eARC was functioning and the dropouts ceased.

...Until I rebooted the beam and there were mini dropouts every 5 seconds. Pulling the optical cable out the beam didn’t clear them, but rebooting the TV did, and the 59s drops didn’t return either.

Reverting eARC to the Sonos provided HDMI cable also reverted the 59s dropouts

I wonder what the minimum set of connected pins is required to make eARC work but not necessarily any other HDMI feature. What might the embedded optical cable transceiver chipsets be telling the TV and/or Sonos when connected in reverse?

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Seeing as there are no new replies I think this still hasn’t been fixed?


we have bought a Samsung wh-q930c for the bedroom (also lg c1) and there’s no issue on that system at all. 

using the optical hdmi still fixes the problem luckily. But lately the screen has been flickering black for 4 seconds before coming back on, as if earc is reapplying.

Also have some audio delay issues on live TV lately; only on Dolby digital streams. Channels that use PCM work just fine, but I think thisnactually is an LG issue since the Samsung had the same thing. 

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Of course if this isn’t actually a Sonos issue, they are free come out and issue an official statement. After all, it’s been 9 months since this has been reported.

I keep getting marketing emails for the Era speakers and just laugh each time as I doubt I will ever buy another Sonos product again after this.

Does anybody have any ideas about getting this picked up elsewhere, maybe the Verge or Peter Pee? Email to Patrick Spence? Does he still reply on Twitter?

I messaged Peter and he responded, but has his Beam connected to a different TV, so would need to move things around a bit to try and replicate the issue. He suggested trying a different cable for these sort of issues (which I had already tried). Fair play to him for at least responding though. 

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Nice one. It is good that you could replicate this.

So whatever the Beam is sending to the TV to cause the drop outs is something that would go down the optical part. I guess that could narrow it down, but I’d guess Sonos already knows what the issue is. Either way, if this workaround works for the long haul, it is good enough for me.


But what do I lose if I just move the Sonos Beam to HDMI 3 or 4 and lose the eArc. Does that just mean I can’t talk to my TV?! 

The audio return is on HDMI 2 only. You can’t connect it to any other port. The optical cable should fix the issues for you though. 

Can also confirm that this “fix” worked. Thanks!

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So after seeing the Verge story about the audio popping issue being fixed I wondered whether this ever got resolved. I can’t easily swap my cable out but may try it seeing as there have been a few firmware updates for the LG CX recently, as well as the Beam obviously.


Anybody still monitoring this?


I guess everyone already gave in and bought the one way cable lol. As for my case, I am still experiencing periodic dropouts on HDMI1 so I think it’s still not yet fixed. Sonos did mention that they specifically addressed an issue with Dolby MAT Atmos.

Remember, Sonos denied the Atmos pop issue for years until that The Verge article came out. Then all of a sudden Sonos investigated and fixed a “non-existent” issue that was previously “caused by your TV / PC / Console / Bluray player / HDMI cable / CEC / Atmos / anything but Sonos’ product.” It would take a The Verge article-level of miracle to get Sonos to fix this issue.

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I think the fact that the mods are not engaging with this thread anymore is telling. I think Sonos have reproduced the issue and so don’t need any more diagnostics or support calls coming in.

At this point they either don’t know how long a fix will take, or how it can be done and hence don’t want to set expectations, or they know it’s unfixable and are hoping this just dies away in time.


Downloaded new update from Korea LG website and updated it from USB. For the moment, it seems the problem is finally solved!! Will see how it goes the upcoming days… Fingers crossed!

Same problem here since Sonos v14 update with LG C1. Really frustrating :(


In my case, I have 1 second cutoff every exactly 59 seconds.


Can confirm drop outs still happen on 15.4. 🙄