Why is the sound out of sync with the picture on my TV?

Every stage that touches the picture adds delay: the set's own processing, upscaling, motion handling, and anything a connected box does before passing it on. Sound goes through far less. The mismatch is small enough to be invisible on some material and maddening on close-up dialogue, and it appears most often the week a soundbar arrives, because the sound has been rerouted while the picture path has not changed.

Step by step

1. Establish whether it affects everything or one source.Check a broadcast channel, a streaming app on the television itself, and a connected box. If only one is out, the fault is in that source or that input rather than in the television as a whole.
2. Turn off the heavy picture processing.Motion smoothing and noise reduction both hold frames back to do their work, which is exactly what creates the delay. Switching to a cinema or filmmaker preset often fixes lip sync as a side effect.
3. Find the audio delay control on the television.In the sound settings, usually called audio delay, lip sync or AV sync, measured in milliseconds. Adjust it while watching someone talking in close-up, which is the most sensitive test material there is.
4. Check the soundbar for its own delay setting.Many soundbars have one too. Adjust at one end only — correcting at both ends leaves you chasing the fault back and forth without ever landing on it.
5. Try a different connection between television and soundbar.If it is badly out over optical, try ARC, or the other way round. Some combinations of set and bar simply handle the timing better one way than the other.
6. Restart both, in the right order.Turn everything off at the socket, wait thirty seconds, then power the television and the soundbar back on. Sync faults sometimes appear after a source change and clear with a proper restart.
7. Accept the limits of wireless sound.Bluetooth speakers and headphones add delay because the audio has to be compressed, transmitted and decoded. Some televisions offer a compensation setting, but a Bluetooth link will rarely be perfect for watching people speak.

Tips

• Dialogue in close-up is the only reliable test. Music, action and voice-over will all look fine when the sync is noticeably wrong.
• If it drifts progressively worse through a programme rather than being a constant offset, that is a streaming or source problem rather than a settings one — restart the app or the box.
• Note the delay value you settled on. Some sets forget it after an update, and knowing the number turns a rediagnosis into a ten-second fix.

Common mistakes

• Adjusting the delay on both the TV and the soundbar — Two corrections fight each other and you can no longer tell which one is doing what. Set one to zero and adjust the other.
• Assuming a new soundbar is faulty — The bar has not changed the picture path at all. It has simply revealed a delay the internal speakers were hiding because they were on the same timing as the panel.

If it doesn't work

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