Multichannel PCM 5.1 dropping out since 14.10 update



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After a movie and an hour of switch gaming no drop outs so far with the new firmware 

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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.

I re-wired my sacrificial Amazon Basics “HDMI with ethernet cable”. Pins 1-12 (3xTMDS data and TMDS clock) are now “open circuit” and pins 13-19 (HEAC/eARC, DDC, HP, 5V) and shield are connected (I finally found my HDMI cable tester as per photo). Behaves the same as the reversed optical cable which means that the active components  (e.g. I2C buffers) inside the optical cable can be eliminated from contributing to the workaround.

My guess is that the TV is losing TMDS clock sync, although there is apparently some control data sent over the TMDS lines too. Either way, you’ve isolated the issue even further, and not only, as you say, should Sonos know the cause already, they could have offered a workaround months ago by defeating their TMDS signal (it’s still not enough evidence to attribute an actual bug to either/both the TV/Beam2).

So, @Corry P - feature request please: a switch to disable the B-roll video stream on the Beam 2 until a full fix is implemented. It’s not like it does anything useful anyway, a “now playing” screen would have been much better use of the video output.

 

I can confirm that the sound cut outs are not there with the Sonos Arc on my LG C1.

On the main page I go to param of (input/ouput)

And I got settings screen: 

 

Thank you for taking the time to show, it’s greatly appreciated. All done and I’ll test it tomorrow! :)

@Fskies Really awesome! Followed the steps you indicated and the problem is solved for the moment (fingers crossed!). Thank you very much for sharing!

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Firestick works FLAWLESSLY. No drop outs, 5.1, 7.1, Atmos all work great.

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.

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 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.

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Hi @RANDUSR23296 

I’m not sure a feature would be added to mitigate an issue that we’re not yet sure is for us to resolve, but that’s not for me to decide. To make a request, however, you’ll need to start a new topic thread with the request in it - please feel free to do so.

It’s never impossible to be a Sonos bug, by any stretch. Just unlikely. But if it were a Sonos bug, there’d likely be thousands upon thousands (relatively speaking) posts about it. 

Sonos is essentially a “dumb” device, at the end of a long chain of things. All it does is play what it’s handed, in whatever form it can, and reports back to the CEC computer on the TV a small amount of data (what type of device it is, what formats it can play, and volume info, as near as I can tell). Sure, it has those things you mention, but if they work elsewhere (for instance, on my TVs, and most other folks installations), then they should work essentially the same everywhere. 

More often than not, the issue tends to be upstream. More so before CEC became a standard, since optical, used on the PLAYBAR and PLAYBASE, was a one way transmission, but still. There’s just not that much going on in the Sonos products. 

Which is why, in the preponderance of posts I make (check me on that, look at many of my posts), I do suggest a diagnostic and a call to Sonos. Just to be sure if it is a Sonos issue, and if it is indeed a Sonos issue, providing the engineering team hard data to look at. All of the engineers I’ve worked with in the last 40 years have wanted hard data, not anecdotal data, otherwise they return quickly with a “it works on my machine” response. 

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There have been calls to support and diagnostics sent in the thread. We have all reset TVs and Beam, changed cables, settings... As far as I know there is no clear answer as to what the problem is or if it is at Sonos or LG side. 

There are multiple posts here and in Reddit about this issue but there is never going to be thousands because it requires a quite specific combination of hardware and settings: Beam + LG CX and above + LPCM Multichannel 5.1 output. It is even possible that many people that have the issue just changed to Dolby if allowed by the affected device to solve it... But this is just a workaround and not always possible...

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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. 

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If you want the issue to reappear again try unplugging and plugging again the beam2/arc from the mains. I have done this for the night multiple times when there was no issue only to find it had returned following morning.

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To be clear I changed the cable between my Apple TV and the LG CX, not the cable to the Beam. I used the stock cable supplied with the PS5 and it has continued to work fine last night and today. The original cable was the Belkin high speed one that Apple sell and recommend for ATV4K. 

I’m fairly certain that I’ve seen the issue with just a single HDMI device connected (PS5 or Bluray) but that doesn’t mean the action of you changing the ATV cable hasn’t triggered a refresh of some cached HDMI handshake value in the TV - possibly @Fskies saw a similar thing when removing/re-adding the beam from the LG menu.

@ste_ms - Out of interest which HDMI ports do you have assigned to the PS5 and which to the ATV? To date I’ve been assuming they behave the same, but maybe some LG C1s have some buggy ports, I don’t recall if I’ve seen the behaviour on both HDMI1 and HDMI3 (I don’t use HDMI4 yet as it’s wall facing and I now have TV on a slim bracket).

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Looks like no fix in 15.2, disappointing as I hoped this would be the one. 

That is disappointing. At least my workaround is still working (see my previous posts if you haven’t already), so I’m happy enough that it will no longer cause me issues. I’ll still follow this for a proper fix though.

For anyone interested, this is a the cable I’m using which fixed the problem for me. 
https://www.amazon.co.uk/dp/B09YPR5SD4

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Looks like no fix in 15.2, disappointing as I hoped this would be the one. 

After 8 months, Sonos still don't know if it's even their bug...

Would be one thing if they can confidently proclaim it isn’t theirs. But to still be clueless after almost 9 months? Bravo. I’m not expecting anything from Sonos anymore. Just biding my time until the next upgrade.

Anyway HDMI1 still works for me and I turn off my power strip 2-3 times a week. I’ve only skimmed recent posts -- does a way one cable disable/downgrade HDMI-CEC? I’ve actually ran out of ports so I use an HDMI switcher on HDMI1 where I connect all devices that regularly use PCM 5.1. I guess that’s another option people may consider.

CEC still working. The only thing you seem to lose is the Sonos image when selecting HDMI 2 (which is pointless anyway). 

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Hi @ste_ms 

@Corry P just checking but if we’ve already been on to support do we already have a case or is there another process to follow?

If you’ve already been in touch, you will have an existing case. Certainly if you received an email afterwards.

Also
​​​​​@RANDUSR23296 has already raised a case as have others possibly, can you confirm if they are being looked at?

I can tell you nothing about someone else’s case.

You mentioned trying to reproduce the issue in an earlier post and then replied saying it was a CEC issue so presumably you were able to reproduce the problem and so maybe are already in a position to identify a fix or at least confirm it as an LG issue?

Not really. My colleague spotted something in the logs and recommended a TV reset. That customer refused to reset their TV and stopped replying - nothing came of it. I don’t think we’ve reproduced anything.

Sorry I can’t be of more help.

 

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Hi @throwawaybeam2 

Welcome to the Sonos Community!

As you have experimented and found this to be repeatable, I recommend you get in touch with our technical support team directly so they can take some diagnostics and gather information regarding this occurrence. Thank you. 

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Hi @throwawaybeam2 

Please recreate the issue and submit a support diagnostic, replying here with the number given. Thanks.

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Hi @throwawaybeam2 

Thanks for the diagnostic. The Beam is reporting underflow errors, meaning that the audio is being interrupted before it reaches the Beam. As this happens with two source devices, the source of the interruption is likely the TV itself, or the physical connection between the TV and the Beam.

If you haven’t done so already, please unplug the TV from power for at least 2 minutes. In the majority of cases, this simple step usually fixes such issues. I didn’t mention it before as you mentioned installing a TV software update - this would include the TV rebooting it’s software. Perhaps it’s the hardware that needs to restart instead.

If this doesn’t help, please swap the ends of the HDMI cable linking your Beam to the TV - put the end that’s currently in the TV into the Beam, and vice versa. Also, are you using the cable that was supplied with the Beam? If not, please do so. If so, please try another (HDMI 1.4 or better).

I hope this helps.

I don’t have an Xbox, but 5.1 multichannel LPCM audio is working okay for me albeit from an Apple TV 4HD connected to a slightly older LG C9 TV with Arc, surrounds & sub. No audio interruptions/dropouts. TV digital audio-out is set to ‘pass-through’, rather than ‘auto’ in the LG sound settings.

Maybe try toggling the TV audio-out settings and perhaps consider removing anything else connected to the other TV HDMI inputs (leaving just the Xbox & Arc connected) to see if that might make any difference. 

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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.

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When I wanted to order the cable recommended a month ago it was out of stock ,other options were quite expensive so I decided to try taping pins 10-12 with a sliver of tape as suggested by @RANDUSR23296 , see page 13 of this thread. HDMI2 does not show the Sonos screensaver anymore (no signal) and I haven't had any audio dropout anymore since 1 month ago. I have not noticed any adverse side effect. If you don't have the cable and/or can't find it you might want to give this a try (be careful though).

LG C2 and having pcm 5.1 dropouts from PS5 in HDMI 3 and 4. Moved PS5 to HDMI 1 so far no dropouts. Having contacted LG support bout this issue and this forum, I have had LG response:

"I am just getting in contact as our Technical Team has responded on file and have advised that there are no differences in the HDMI ports and so there should not be any reason as to why HDMI 3 and HDMI 4 would be different to HDMI 1. They have advised that we can book this in for a repair as this could be an issue with the HDMI 3 and 4 ports themselves."

So am now booked in for HDMI repair. 

Waste of time IMHO, your TV behaves exactly the same as any other LG TV of its model.

It works “as intended”, the problem is that the “as intended” is faulty.

It almost seems to infer that the LG Technical Team are aware of a hardware issue with that TV model. I would have the repair and just see what happens after that.

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Hi @OmriP & @mjsound 

I personally really don’t know much about it - I just found the information and shared it with you.

A search will reveal that many people with these particular TVs and all kinds of (non-Sonos) audio equipment experience the same. Here are three examples:

https://www.avforums.com/threads/lg-c1-oled48c16-issues-with-5-1-lpcm-over-earc.2422032/

https://www.reddit.com/r/LGOLED/comments/v9ly92/lg_c1_after_new_update_033006_uncompressed_51_and/

https://discussions.apple.com/thread/254122268

The issues also coincided with an LG firmware update for these particular models, and LG are actively seeking videos and other evidence from their customers in an effort to troubleshoot.

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Hi @throwawaybeam2 

A good test would be to play 5.1 PCM from the PC, but without the PS5 connected to the TV, and after a TV power cycle - if the issue doesn’t occur, then disabling the PS5’s CEC  options would be a good place to start, then try a CEC-less adaptor if that doesn’t help. Having said that, I’d still recommend trying the free option of a TV reset before spending any money.

If, however, the PC gets interruptions without the PS5 connected, then I recommend the reset of the TV.

If neither resetting the TV nor disconnecting the PS5 fixes the problem, it really would be best to get a case created by getting in touch with our technical support team via chat or email.

 

The point of this forum, as indicated by its title at the top of the page, is a ‘Community Forum’, and not a ‘Sonos Support’ Forum.

If you want to talk with Sonos Support directly, I would recommend that you call them, rather than relying on a forum moderator to act as a Support person.

If you’re to go to the bottom of this page, and click on ‘Contact us’, you’ll find instructions on how to do so,

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