[Tom Wilson7]

I bought an LG 43UJ630V TV and a Samsung HW-K450 soundbar 2 weeks ago.
When connected to the soundbar (either digital optical or HDMI ARC), they are in sync.
When left on for around 2 hours though, I'll start noticing the lips are not correctly syncing up with the words.
By the 3-4 hour mark being left on, it's atrocious.
I expect to have to have to set the av sync initially, but changing it every hour as it slowly drifts out of sync - this is clearly a technical fault.
When I plug the soundbar directly into my Sky box (set-top box) there are no issues of drifting audio sync.
Changing settings, updating firmware, using different wires, nothing makes a jot of difference unfortunately.

I determined the problem was with the processing of the digital output audio signal in the TV's internals.
I returned my TV for a replacement, and bought a new sound bar to go with it - an LG SH4D 2.1 - figuring that the samsung soundbar may have been incompatible.
Yesterday I set it all up, but found after 3-4 hours of being left on, the audio was wildly out of sync again.



In this example I set the audio so it would output via digital output and internal speakers. The latency between the 2 is so bad you can't even call it echo. This demonstrates how badly out of sync the soundbar output gets compared to the internal speaker.
Remember - this is my second 43UJ630V and a different soundbar, and yet the problem returned in exactly the same way.
After recording that video I tried connecting my Samsung soundbar instead and it was exactly the same.

There is clearly a fault with this model or the entire UJ630V range.
I hope it can be fixed in a firmware update.
Ignoring momentarily the fault, and the countless hours and stress this has caused - I rather like this model. I'd prefer to fix it instead of sending it back for a refund.

I don't understand why I cannot find anyone else reporting the same problems. When I spoke to LG a week ago describing the problem, they told me a fault like this hadn't been reported before... But I've proven beyond a doubt that the problem is there, and probably afflicts a great number of people.
I've emailed LG but I'm sure they'll just fob me off again. I plan to give them a ring later, but again, I'm not sure what good this will do.

I've diagnosed the problem, and I cannot be the only one experiencing this problem. It is probably addressable in a firmware update if I can bring it LG's attention.
Any help or suggestions would be appreciated.

[Preemptive]

There is clearly a fault with this model or the entire UJ630V range.
I hope it can be fixed in a firmware update.
Ignoring momentarily the fault, and the countless hours and stress this has caused - I rather like this model. I'd prefer to fix it instead of sending it back for a refund.

I don't understand why I cannot find anyone else reporting the same problems. When I spoke to LG a week ago describing the problem, they told me a fault like this hadn't been reported before... But I've proven beyond a doubt that the problem is there, and probably afflicts a great number of people.
I've emailed LG but I'm sure they'll just fob me off again. I plan to give them a ring later, but again, I'm not sure what good this will do.

I've diagnosed the problem, and I cannot be the only one experiencing this problem. It is probably addressable in a firmware update if I can bring it LG's attention.
Any help or suggestions would be appreciated.

You state that this is clearly a fault with the entire range, but also that you cannot find another example reported on the web. Such an obvious fault would be... well, obvious! If common, I'd expect a recall or swift firmware update. A 'soak test' is when a unit is left on for many hours to see what faults develop over time. I don't know what LG's testing routine is, but I find it hard to believe such an intrinsic fault would slip through - especially with their own soundbar.

So the sound from the internal speakers stays in Sync, but the sound bar drifts out? I'd expect a sync error to be consistent rather than drifting. Does it continually worsen or stop at a certain offset?

If we assume that it's not a fault in the whole range and that if uncommon, it's unlikely to also affect a new set and sound bar, then what else has stayed the same in your setup? Could it be the way you are setting the sync? Have you tried a source other than the Skybox? Like Freeview, a DVD or digital file? As you say, it seems like a processing error, but perhaps the source of the error is from the source or it's setup? (or the way the TV is set to process it)

My best guess is to look at the parts of the system that haven't changed and swap them out - sources, settings (in all units), perhaps connections... The really weird thing is the drift in sync.

You maybe right that all these TVs have the same fault, but sync errors that appear in a couple of hours are really obvious - I'd expect you to be seeing a lot of this on the web if it was so common.