When Sonos dialogue does not match the picture, first determine whether the sound is early or late. Adding audio delay can help early audio but cannot bring late audio forward.
Run a controlled check
Choose a scene with a clear view of someone speaking and note whether you hear the syllable before or after the mouth moves. Repeat with a TV app and an external source, if available. Write down which input is affected. A problem limited to one input is a reason to investigate that input before replacing the soundbar.
Decide what to change
Sonos’s troubleshooting guide separates audio ahead of video from audio behind video. If sound is early, try a small TV Dialog Sync adjustment and replay the same scene. If sound is late, check the TV and source settings described in the guide instead of adding delay. Record the original setting so you can undo any change that makes other sources worse.
Worked example
Example: if a streaming app on the TV is in sync but a console shows delayed sound, leave the TV-wide delay alone while you diagnose the console. If both sources show early sound, note the original setting, test one adjustment, and confirm it works on both before keeping it.
Documentation and next step
See the manufacturer’s instructions for supported settings and model requirements. For a related setup decision, see sonos atmos signal format before hdmi upgrade.
