Nothing shatters the illusion of life faster than loose, lagging mouth movement. In traditional 2D animation, aligning mouth phonemes directly with audio waveform spikes creates an uncanny sluggishness.
### Why Sound Lags Behind Sight
Light travels faster than sound. Psychologically, human viewers expect to see mouth articulation begin 1 to 2 frames (40–80 milliseconds at 24 FPS) before acoustic sound reaches the ear.
### Impact Hit Synchronization
Unlike dialogue, physical impacts—such as punches, sword clangs, or door slams—must connect on the exact frame of the audio hit, with squash and screen shake firing immediately on frame +1.
### Plan Your Scenes in Pre-Production
Use our [Storyboard Planner](/tools/storyboard-planner/) to block voice cues and sound effects alongside shot timings.