Multichannel PCM 5.1 dropping out since 14.10 update



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

My dropout frequency has also change now to every 59.8 seconds, but the drop remains approximately 1 second. The only relevant thing that I’m aware has changed (other than the dog destroying the TV remote) is Sonos firmware, now on 14.18 (without the grey dots in the app).

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The dropouts are back again, completely randomly.

Turned on the TV and they’re suddenly back after several weeks that they were gone.

Nobody cares apparently.

Neither Sonos nor LG got back to me even after contacting support multiple times.

This was my first and last Sonos product.

Completely embarrassing service and support.

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5.1 PCM started to work fine with PS5 and LG CX 3 days ago. It worked perfectly for two days, 3-4 hours of gameplay each day and no cutouts at all, until I had to cut power from all three devices, and now the issue is back again. I wonder what did I do to make it work for 2 days?

EDIT: I just read this thread a bit more and realized that the same happened to a lot of people before, but then the issue came back again. Sigh...

Thanks for taking the time to post the new data point. It seems that LG C3 chipset isn't drastically different to C1/C2.

Indeed, power cycling the Beam2 should re-instate the dropouts immediately.

Sorry, maybe I was unclear. I have an LG CX, not a C3. 

Ah, got it. Sorry, I misread your post. It was @Retcon with the C3, I should have scrolled up to double check before replying.

Awesome. I'll try it myself today. 

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Sounds like it’s an issue in the TV set somewhere. Sonos plays whatever it’s handed. 

Couldn't possibly be a Sonos bug, right? Despite the Beam 2 having internal audio buffers for lip sync, true play, multi-room, and having CEC control and HDMI handshakes and considerable DSP. Could be in the C1 too from the experiences posted, but let’s try to remain objective and keep the apologist rhetoric to the first page of these threads?

Edit: That being said I noticed there is a new LG C1 firmware released (03.33.26) which I have yet to install, will report back if this changes the behaviour of the dropouts

I applied the update and I still have the issue. I think I read somewhere that HDMI-CEC might be broken. I'm going to try restarting everything and see if that helps. I can't disable CEC on the TV while the Beam is plugged in.

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Interesting reading those papers about eARC - the ITE paper states that TMDS signalling is limited to 4/8/16 channels. Perhaps that’s why everything was 7.1 (8 channels)?

if the new ATV4K has moved to FRL signalling then perhaps that’s why it now outputs 5.1. Possibly the PS5 has also switched to FRL signalling hence the fix to 5.1 that came a few firmwares ago.

is FRL the culprit somehow? 

 

I've tried a few video modes now but can't get ATV4K Gen 3 to use FRL, it's always TMDS. I doubt FRL is in there, the bandwidth isn't needed for the video modes Gen 3 supports. Apple must have changed something else more fundamental between Gens 2 and 3.

Not sure if the ATV is aware of the Beam 2 during the handshakes, or if the LG just reports it'll accept audio formats that it knows it can "pass through” based on the eARC capabilities received from the Beam2. I did also test that Gen 1 incorrectly negotiates 7.1 with my eARC AVR in place of the Beam2 on the C1, but does get 5.1 correct on the A1

Coming to this late but wanna add my experience here. LG G2, Beam Gen 2 via e-Arc, 4K Firestick in HDMI 1, PS5 in 3 and Nintendo Switch in 4.

Firestick works FLAWLESSLY. No drop outs, 5.1, 7.1, Atmos all work great. PS5 works perfectly when playing games, but trying to watch a Blu Ray is a lottery whether it will play (only after TV hardware reset) drop out intermittently (sometimes not coming back at all) or just no sound from the off. Nintendo Switch audio drops out for a second every couple of minutes.

With the Blu Ray issue being fixed by a TV hard reset I initially thought it might be a TV issue, but I used a SONY soundbar via e-Arc before with absolutely no issues. I thought the Sonos would be an upgrade but this issue is making me strongly consider returning it. This is not budget equipment, I shouldn’t have to lose my evenings trying to get it to work properly…

I was just in a chat with Sonos support, who said to purchase a CEC-less HDMI cable to fix this issue. Which is ridiculous as everything was working fine for me until recently. I’ve noticed that the HDMI 1 port on my LG CX isn’t affected by this bug, it’s only HDMI ports 3 and 4 but if I switch the HDMI cables then HDMI 1 is affected. 

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So a few months ago we had confirmation that Sonos were investigating this issue - can we get an update @Corry P?

I remember about the same time somebody had a response from Sonos saying that they were committed to resolving the issue - did that person ever get a follow up from Sonos support?

This issue is so widespread on sonos reddit  and here that i cannot recommend buying sonos if u have a ps5 and lg tv. The bug has been around for 6 months. I too have this issue and none of the fixes will stop the dropouts.

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So a few months ago we had confirmation that Sonos were investigating this issue - can we get an update @Corry P?

I remember about the same time somebody had a response from Sonos saying that they were committed to resolving the issue - did that person ever get a follow up from Sonos support?

 

I was that person and no nobody ever contacted me back.

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So a few months ago we had confirmation that Sonos were investigating this issue - can we get an update @Corry P?

I remember about the same time somebody had a response from Sonos saying that they were committed to resolving the issue - did that person ever get a follow up from Sonos support?

 

I was that person and no nobody ever contacted me back.

Well the Sonos mod did say “Please don't expect an immediate resolution” on the pinned response from 2.5 months ago. And this thread is nearing its 1 year anniversary. Wonder what the word “immediate” means in Sonos Time™?

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I have the impression that the issue goes away more often by itself, even if it comes back... Right now audio is ok for almost 2 days... Difficult to say if this is placebo or the latest updates changed something related to the issue...

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Just a heads up, an easy way to test this is with a switch. It only outputs 5.1 pcm surround sound (besides stereo & mono) as far as I know. It’ll sometimes work for a week, start dropping out , I’ll tinker, it’ll work again for a limited time. Sometimes only on one HDMI port, makes no sense.

After two days the issue returned unfortunately

The HDMI 1 workaround is not perfect as I’ve always gotten around one or two dropouts every hour with PCM 5.1. Perhaps you just haven’t noticed or you’re lucky that yours hasn’t bugged out yet.

Don’t know if it’s even an HDMI 1 workaround, tried the PS5 in HDMI 1 and it didn’t solve the issue. The Firestick just seems to deal with issues better than any other device. It’s by far what I’ve used most since I got the Beam so I think I would’ve noticed dropouts, but as you say it just might not have bugged out yet. I’ve also experienced some other weird quirks with it - If I have the Firestick set to “best audio possible” I get no sound when I set the Nintendo Switch to surround, full audio on stereo, but if I set the Firestick to PCM, I get surround on the Switch, but it regularly drops out. There was a brief moment where everything worked perfectly (Switch and PS5) if I disconnected the Firestick completely, but then that seemed to stop working too…

I also used a Sony earc soundbar with no issues before “upgrading” to the Beam. Since you have multiple devices that make use of PCM 5.1, I suggest that you either buy the fiber optic cable or simply return your Beam. Personally, I’d go with the latter as Sonos has already lost my trust. From what we’d seen from the Atmos pop (and this) issue , they’d just sweep things under the rug and deny any wrongdoing unless it has garnered widespread media attention.

I’m gonna try the cable as I get get one for £11 on Amazon in the UK, more out of curiosity than anything, but maintain that it’s unacceptable for a product to come with a cable and for me to still have to purchase one separately to get it to work properly. Was looking into alternatives if I do choose to refund and the closest comparable device seems to be the Bose 600, but the more I look into that the more I see pages and pages of people complaining that it doesn’t work properly with LG TVs! Starting to think my basic SONY soundbar worked so flawlessly because that’s all it was - just a decent soundbar, no bells or whistles. While I don’t think it is a TV issue, it seems that some of the blame has to lie with LG here - there are too many variables for this to simply be “the Beam can’t do 5.1”

 

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The issue had been gone for a while without me having to do anything, so I thought perhaps some update had fixed it. However today the TV received a software update and the issue returned immediately afterwards. I’m thinking software updates (as well as power outages) somehow “reset” the state of the tv, including reintroducing this bug.

Anyways, nothing I’ve tried so far worked.

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Hi all,

I’m having the same issues.

I’ve recently bought a Sony UBP-X700 4k Blu ray player. Up until now I’ve been using my PS5 but wanted to take advantage of the Dolby Vision and better quality from a 4K player.

However, any 4K disc that doesn’t output Dolby Atmos seems to have issues. It outputs the audio as Multichannel PCM 5.1 but every 20-30 seconds I get a momentary drop out of audio and sometimes no audio output at all. As I said Dolby Atmos plays fine.

My setup:

TV: LG C1

Sonos Beam 2

2x Ones as surround

Sub Gen 3

I had similar issues when first trying 4k discs on my PS5 but I bought a better HDMI cable and this seemed to fix the issue. I’ve done the same this time to no avail.

Any help would be greatly appreciated or if a fix is known.

thanks

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I just noticed that there is a new firmware for LG C1 and a new Sonos update, I won’t be home for a while so I can’t test, did it solve the dropouts by any chance ?

I don’t see a new update, was it 14.2? 

Seems odd that power cycling the Beam reverts to the dropouts, but does power cycling the TV? Is there some sort of HDMI negotiation that happens only when the Beam powers up versus pulling the HDMI cable?

It’s also odd that I can hot swap another eARC device but only the Beam has the dropouts, as if the the buggy state is in the Beam, or the LG is remembering devices that have previously negotiated on power up (or the two devices are just using somehow different flavours of PCM 5.1 on the wire, hard to tell just by trusting the status labels of the vendor’s apps).

I’ve only noticed when power cycling the beam - basically whenever there is a software update. Power cycling the TV often fixes it actually. 

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I also noticed a lot of discussions elsewhere. I have got another support call scheduled tomorrow and if I just get told to unplug and re plug again etc I’ll be tempted to try and get a refund under UK law. I had a playbar which was flawless but eARC has clearly been rushed and Sonos do not seem particularly bothered to try and use the resource of this community to resolve the issues 

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One thing I don’t understand though is why HDMI 1 is unaffected. While this may be an unpopular opinion, I think this fact suggests the problem may be the TV after all…..

Purely speculation, but maybe HDMI 1 and 2 share a bus on the board, and 3 and 4 share another. 3 and 4 are affected as they are on a different bus to the Beam Gen 2. So the signal from the Beam Gen 2 to the TV is normal, but the TV deals with it incorrectly on HDMI 3 and 4 or it has an issue passing it between busses. Again… this is purely speculation.

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I tried with different cables also, I am afraid it will come back ;) (hopefully not, in that case, could you let us know the name/model of cable please?) I would understand if you wouldn't want to do it but could you unplug and plug again the soundbard ? I fear the chances of the issue coming back just by doing that are pretty high...

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.

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Hi @ste_ms 

Unfortunately, I have no further information to share at this time.

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