LG TV Lip Sync / Audio Delay With a Soundbar: Fix

Lip-sync delay on an LG OLED (C3/C4/G4 and similar) with a soundbar is a settings fix, not a gear problem. Two things cause nearly all of it: the soundbar adds processing delay the TV doesn't know about, and LG's TruMotion picture processing adds picture lag. LG gives you a direct AV Sync Adjustment slider for the first, and turning off the second handles the rest.

Fix it

1. Use LG's AV Sync Adjustment. Settings (gear) > All Settings > Sound > Additional Settings > AV Sync Adjustment. Watch a talking head (news anchor) and slide until the lips match. This is the primary LG fix when the soundbar's audio trails the picture.
2. Adjust on the soundbar too if needed. Many soundbars (LG, Sonos, Samsung, Sony) have their own Audio Delay / Lip Sync setting in their app or remote — use it if the TV slider can't pull it far enough.
3. Turn off TruMotion. Picture > Advanced Settings > Clarity > TruMotion = Off (or use Game Optimizer / Filmmaker mode). TruMotion adds picture-processing lag that throws audio ahead of video — switching it off often fixes sync on its own.
4. Set the right audio output mode. Sound > Sound Out > HDMI (eARC). Make sure it's pointed at the soundbar over eARC, and that Simplink (CEC) is on. If the soundbar goes silent rather than just out of sync, that's a different fault — see LG soundbar no audio over ARC/eARC.

If sync still drifts

• Format latency: decoding Atmos/DTS adds delay vs. PCM. If sync only drifts on certain content, set Sound > Sound Out > Additional > Digital Sound Out to PCM to test.
• Marginal eARC link: an unstable eARC connection re-handshakes and shifts sync. Use a certified Ultra High Speed cable on the eARC port. If you're not sure your setup needs eARC over plain ARC, the ARC vs eARC differences explainer covers what each carries.
• Power-cycle the TV and soundbar (unplug 30+ seconds, soundbar first) to clear a one-off misaligned handshake.

FAQ

Where's the lip-sync setting on an LG TV? Settings > All Settings > Sound > Additional Settings > AV Sync Adjustment. Slide it while watching someone talk until lips and audio match.

Audio is ahead of the picture, not behind. That's usually TruMotion adding picture lag. Turn TruMotion off (or use Filmmaker/Game mode), then fine-tune with AV Sync Adjustment.

The TV slider isn't enough. Use the soundbar's own Audio Delay setting too — the two adjustments stack.

It drifts only on some shows. That's audio-format decode latency. Test with Digital Sound Out set to PCM, and make sure the eARC cable is certified and solid.