Symptoms
- Voices don't match mouth movements
- Delay gets worse the longer you watch
- Sync is fine on live TV but off on streaming apps
- Problem appears only with a soundbar or receiver connected
Likely causes
- CommonSoundbar or AV receiver audio processing delaySurround sound and enhancement modes add processing time that isn't matched to the video delay.
- CommonWeak network connection causing buffering catch-upWhen video buffers and audio doesn't, sync can drift.
- PossibleOutdated app or device softwareSync bugs are sometimes introduced and fixed in app updates.
- PossibleHDMI-ARC audio delay mismatchAudio return channel setups can introduce a small but noticeable lag.
- Less commonTV's own audio processing (noise reduction, etc.) adding delaySome picture/sound enhancement features add latency.
What to do
- Check your soundbar or receiver for an audio delay or 'lip sync' adjustment setting and tune it manually.
- Turn off surround sound enhancement or virtual surround modes temporarily to see if sync improves.
- Restart the streaming device and the sound system together.
- Check your internet speed, since a weak connection can cause the video to buffer while audio keeps playing.
- Update the streaming app and device software to the latest versions.
- Try switching from HDMI-ARC to an optical audio cable if your soundbar supports it, as a test.
- If sync issues happen only on one specific app, report it to that app's support as a known bug.
Tools and parts
Optical audio cableSearch: “optical audio cable TOSLINK”
When to call a pro
No professional repair needed; this is almost always a settings or software issue.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.