General discussion

LG 43UJ630V - Audio latency gets worse the longer TV is on

I have an LG 43UJ630V connected to a Samsung HW-K450. The firmware is up to date.

At first glance, the issue would appear to originate from the soundbar, but I'm almost certain the fault is with the TV and the way it processes & delivers the output signal to the HDMI ARC and digital optical outlets.

Here are my symptoms:

When the TV is turned on, the audio sync is excellent. No AV settings needed, no delay on the soundbar. Perfect.
However, over the course of a few hours the audio slowly begins to go out of sync. It gets worse and worse, until I'm forced to take action because it's so intolerably bad.
When it gets this way, AV sync settings for some reason cannot fix it. If I set the delay on the soundbar, it may temporarily correct it, but because the audio latency goes up and down over time, it's not a permanent fix by any measure.

When the soundbar is turned off and it defaults to the internal speakers, the delay seems to disappear.
I could leave the soundbar disconnected for 10 minutes, but as soon as I reconnect it, the issue returns.

However!!! - If I leave the soundbar connected and simply turn off the TV and back on again, the issue is resolved... until it slowly returns an hour or so later.
This would suggest the soundbar is not at fault here - the LG TV is.

Watching TV the last few days has not been a relaxing way to unwind at the end of the day. It's a chore, headache-inducing and incredibly frustrating.
I'm 99% sure the issue is with LG's product, and am encouraged by seeing so many others post about similar issues regarding the audio sync.
I haven't come across a single case though like mine, whereby the audio drifts slowly out of sync over the course of hours.

I've tried turning off all the potentially intensive/processor-hungry picture settings, forcing PCM output and everything else practically.
My guess is it might be resolvable with a firmware update, considering the success of a recent firmware update which resolved a similar issue for a different range of LG models, but how long should I wait until I give up and send it back?

Any advice or ideas are welcome.

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Reply to: LG 43UJ630V - Audio latency gets worse the longer TV is on
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I think you have to work this statement.

"delivers the output signal to the HDMI ARC and digital optical outlets."

That should be "or" and not "and".

HDMI ARC is full of misfires and flaming posts on the web. Optical should be fine so try it without the HDMI to the 450.

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Re: I think you have to work this statement.

It went out of sync again last night - and although I've tried it multiple times before with no improvement - switching from ARC to optical appeared to fix it this time.
I'll keep it connected via optical cable and wait to see if it goes out of sync again tonight.

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Still goes out of sync...

Just wanted to confirm that the digital optical output also goes out of sync.
It's useless.
It's probably a firmware related issue but there's no fix coming it seems. LG haven't replied to my emails explaining the problem either.
It's staggering that this issue exists in the first place with so many products, how could they not have realised?

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The plot thickens!

Last night I plugged my Sky Box into the soundbar via digital optical, while I watched the picture signal via the Sky's RF Out as an analogue channel, thereby reducing the TV's functionality to a glorified monitor.
There's no other way to connect the sky box to the TV unfortunately, as it's an old model with only scart and composite output, so I have to use this very unusual method of programming it as an analogue channel (C68), and herein may lie the problem, more on this later...

The sound was a little bit out, about -75ms, but you would expect the visual data to take a little longer to get to the screen with this unusual setup.
It appeared not to drift out of sync for a good 4 to 5 hours.
Great. This confirmed that the problem does indeed lie with the TV, or so I thought...

I drifted off at about 10/11 and woke up at midnight. The TV was off, it must have an inbuilt sleep timer if there's no interaction for a long period of time.
While the TV was in standby, the sound was still coming out the soundbar because it was connected to the Sky Box.
Remember, the TV at this point is functioning much like a glorified PC monitor.
When I switched the TV back on, the sound and picture were out of sync by about 500ms.
I was completely flummoxed, and am still.
I thought I had deduced the problem lay at the TV's external output, but I wasn't even using the TV's HDMI ARC or digital optical outputs, so maybe this isn't the case... unless this new symptom I've described is something different, which I can't dismiss either.

Now I have no idea where the blame lies.

Is the soundbar going out of sync?
Is the TV's external audio output going out of sync?
Is the TV's picture (visuals) going out of sync?
Or maybe there's something up with the way that the TV processes analogue signals (Sky RF Out) that causes this problem. That said, when I switch over to one of the inbuilt Freeview channels ( we have an aerial input as well going through the Sky box), the problem persists. Considering my unusual setup, maybe this is why nobody else has experienced the problem. It may indeed be a firmware related issue with the TV, and I may be the only person to have reported it because who uses analogue nowadays?
I need to conduct more tests with the inbuilt Freeview. Maybe watching the Sky signal too long causes it to go out of sync, and the Freeview channels don't restore sync, but don't make it any worse. I mainly watch recorded shows on Sky+ so I can't test this easily unfortunately.

It is very notable and not to be ignored, that the av sync when plugged into the Sky box didn't drift over the course of about 6 hours (not to my eyes anyway). Usually by then I would've had to have turned off and on the TV on 2 occasions to restore sync.
So the issue I experienced last night may be a separate thing.
Still, I can't quite get my head around why that happened last night.

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just one word for that


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More Tests...

I have a really sh*tty scart converter (terrible quality picture and sound), so I can hook up the old sky box via HDMI.
I'm currently conducting a test whereby I have the soundbar connected to the sky box (digital optical) and the picture via the converter as an HDMI input, but I've set the sound settings on the TV to output through the soundbar AND the builtin speakers.
Initially, I've set the soundbar's audio sync settings so that it's perfectly in sync with the builtin speakers.
By my theory - if the audio from the soundbar starts to go out of sync (which will be easily detectable as it'll sound like echo), then the soundbar is definitely at fault. Otherwise, I'm back to suspecting the TV/sky signal is at fault.
I will report back with the results.

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Further developments...

The internal speakers and soundbar have been perfectly in sync with each other all day, the picture on the TV however appears to have drifted out of sync a little bit. Only subtly, but still quite noticeable.

As strange as it sounds, I think all of this may be down to my unusual method of audio+visual delivery - via the Sky's RF Out as an analogue TV channel - and a problem in the way it's processed by the TV.
I believe I've chanced across a very rare & undetected bug in the hardware/firmware.
The TV must be calculating the visual timing incorrectly when it's given an analogue signal to process.
There's just no other way to explain all the symptoms I've experienced so far in a single theory.
Maybe a simple rounding error means the audio and visual buffers slowly go out of sync... Something like that.
I would estimate at least 99% of people don't pick up any analogue signals so have never experienced this bug.

My unusual setup is only a temporary measure until we get Sky Q, but it's still a couple weeks away so I've ordered a multi-directional Scart to AV cable. It should arrive tomorrow or the following day, then I can finally connect the sky box to the TV in a reasonably standard way. Maybe that will resolve the issue once and for all.

If only had listed it correctly as having AV input capability, it may have saved me an awful lot of bother (and £10 for an absolutely crap scart to HDMI converter)

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It's hard for me to pick out what components are in play.

If you have some OLD SKY TV BOX then that is just what it is. I may be mis-reading you but without HDMI it's going to be AWFUL and BROKEN.

I do not expect it to work or find any maker willing to fix that.

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Re: It's hard for me to pick out what components are in play

There's no good reason why the audio and visuals would go out of sync.
Saying 'it's old' just isn't good enough.
If it has an analogue tuner, I'd expect it to work correctly.

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I don't expect it to work right.

If you feel it should work, then get to the makers and demand they fix their stuff. But anything 5 or more years old, they usually ignore folk. I did not write this was right, just it is like this.

Sometimes you get a client that gets upset when old gear won't work with the new stuff. Best to nod and let them rant. Eventually they get what's going on and change up to parts that work together.

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2nd try. It's hard for me to pick out what components are

"It's hard for me to pick out what components are in play."

I should have asked for a clean new reply with "just the facts."

We know that many convertors work and others introduce new issues. If you tell me the Sky box ANALOG output to the TV loses sync then you told me it's the Sky box.

What happens if we remove the Sky box?

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Replacement TV has same fault with different soundbars...

It turns out I was correct in my diagnosis.

New LG 43UJ630V + new LG soundbar connected to TV via digital optical = the exact same problem.
When I switch the audio setting to digital output & internal speakers, you can observe just how terribly out of sync it can get:

Apologies for the crap example to demonstrate the problem, but I can assure you the internal speaker output was more or less correctly in sync with the picture, while the soundbar output is almost a whole second late.

This is with a different make and model of soundbar (LG SH4D 2.1) and a replacement TV (still LG 43UJ630V).
I plugged in the Samsung soundbar after recording the video above and the problem didn't resolve.
Also note with my replacement model I intentionally did not install the latest firmware to see if the problem may have been in the update (My previous LG 43UJ630V was up to date and had the same issue)

Assuming I've not stumbled across a rare fault twice (too unlikely to consider), the issue clearly lies with LG and this model/range of TVs, particularly the way the digital audio is processed and delivered via the outputs.

This is LG's page for the UJ630V range:
LG 43 LG ULTRA HD 4K TV | LG Electronics UK

It comes in 43", 49", 55", 60" & 65". I assume they contain very similar, if not identical internals, so I can assume the entire range is susceptible to this problem with external audio devices.

Also recall I have tried practically every audio / picture setting and it did not resolve the problem.

Considering the run-up to Christmas & the great price, I'll also assume that many people have bought this TV (or another model in the UJ630V range) with a soundbar and are experiencing the same problem right now.

What do I do now?
I'll be sure to get in contact with LG tomorrow, but this is nuts. It's almost a whole second out of sync!
How on earth was this problem not spotted earlier, and why do I appear to be the only one noticing and voicing this problem anywhere on the internet?
I've sufficiently proved that the problem is apparent across not just my TV, but countless others in theory.
I can't be the only one to have sent back a TV or soundbar due to this.

Christ, what an incompetent company.
I deserve compensation for the crap they've put me through.

Besides phoning or emailing LG, what should I do next? I'd love to hear some more suggestions.

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I have the same fault with a LG - 43UJ634V & Yamaha YSP1000

Did you get this resolved as I have the same fault with the optical output to my Yamaha YSP-1000 soundbar?
Sent the first TV back as it was assumed to be faulty, but replacement is exactly the same ; getting fed-up switching the TV off & on to re-sync the sound.....

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I just purchased a LG65SK900PUA 4K SUPER UHD on 9/01/18. I do not have a sound bar. I have the same problem, and as you said, it increases with time. I feel like I'm watching a really bad Godzilla movie. I am taking it back today after reading all of the problems that you and other people on this forum are having. I will NOT be buying another LG. My question is how long before LG fixes this issue? I have never had an LG before and I will never have another! I will also share it with everyone I know!! What a waste of our valuable time!!

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Same issue

I'm having the same issue. I've tried everything to no avail. So frustrating

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Me Too

Take it back! LG is a terrible company!

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Same sync issues - work around for us but no bluetooth

Used TV Optical from tv to soundbar and removed all Bluetooth devices from TV pairing list. Everything now back to staying in sync. Soundbar remote is set to TV. All sound now controlled through TV remote.

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So far so good.. LG audio sync

I've been having same issues with optical cable and with HDMI ARC. I've been cycling power on soundbar, change channel, change back, AV sync settings on Sound bar all to temporarily resolve as problem returns and worsens as time goes on (minutes, hours). This post inspired me to try a few things and found that setting the AV Sync Adjustment to Off on the TV -OR- setting AV Sync Adjustment to On and Bypass to ON seems to resolve..perfect for nearly an hour now.

LG - SK10Y Soundbar
Spectrum Cisco DVR
LG-UBK90 4K Player
All HDMI connections

HDMI ARC audio from TV to Soundbar

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So far so good (NOT).. LG audio sync Update...

The problem came back, but seems a little better. I have only noticed it with the Cisco cable box. Smart TV, 4K player not used as much, but haven't noticed.

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I have had the same problem for about 12 months. I will report it to LG, hopefully if enough people do, they will resolve it via an update. Unfortunately most people will just keep changing channel and returning for a temp fix, it gets frustrating when it needs doing every 5 minutes though!

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+1 here

This is boring... How long shall we wait until they fix it?
Please people if you find a workaround or if something worked for you, let us know.

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Brand new LG65SK8000PUA. Purchased two weeks ago on Black Friday. Sound/Picture sync problem as others have noted already. The longer without changing channels and remaining on one program the worse it gets until it is so noticeable it's difficult to watch ( within 10 minutes or so). Change channels, switch back, better short term and then same issue. Thanks to all that have posted. I'm returning set this morning and not buying another LG. Too bad...I like the picture and remote. Have a Polk Soundbar , and even think the sound direct from the set is decent. Can't live with the lag.

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Same issue with Sony

I have exactly the same issue with my Sony tv and soundbar. Drives me crazy. I suspect my cable box is involved since the problem is much less pronounced when I stream

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