How to sync sound effects to your cuts

1. Find the frame of the action. Step through the shot one frame at a time around the moment and stop on the first frame of contact: the heel touching the floor, the door meeting its frame, the first frame of the new shot. In CapCut, the arrow keys move the playhead one frame.
2. Mark it. Drop a marker on that frame so you can find it again and snap to it: M in Premiere Pro and in DaVinci Resolve, and the Add marker tool in CapCut. Mark every hit in a sequence before you place any sound.
3. Turn snapping on. Snapping makes a dragged clip jump to markers and the playhead. Press S in Premiere Pro (Snap in Timeline) or N in DaVinci Resolve; CapCut calls it Auto Snapping.
4. Line up the peak, not the start. Most sound files begin with a little silence or a build, so the start of the file is rarely the moment of impact. Find the loudest point of the waveform and put that on the marker. In the Resolve Sound Library, a Sync Point does this for you.
5. Nudge by single frames. Move the clip one frame at a time until it feels right: Alt+Left or Alt+Right on Windows and Cmd+Left or Cmd+Right on Mac in Premiere Pro, comma and period in DaVinci Resolve. Add Shift to move five frames in either editor.
6. Let the sound lead or follow the cut. Ambience often works best starting a little before the new shot (a J cut) or carrying past it (an L cut). Unlink the audio from the video to offset it: turn off Linked Selection in Premiere Pro, or hold Option (Alt on Windows) to select only the audio in DaVinci Resolve.
7. Fade and level it. Fade the tail so the sound does not end on a click, crossfade sounds that overlap, and keep each hit under the dialogue around it with volume keyframes. Then play the passage back at full speed: sync that looks right frame by frame can still feel early or late in motion.

Most hits belong exactly on the frame of contact. A few habits from film sound are worth knowing:

• Impacts and footsteps go on the contact frame. A step that is a few frames late makes the character look like they float.
• Whooshes should peak on the cut or the fastest frame of the motion, so their build starts before it.
• Reactions (a laugh, a gasp, a crowd cheer) come a beat after the event, because people react after they see.
• Distant events like fireworks or thunder can land a little after the flash, as they would in life.

When a cut and an action fall close together, favor the cut: viewers feel a sound that is off the edit more than one that is off a small movement.

Placing dozens of footsteps or hits by hand takes time. Sonilo can generate sound effects from the video itself, timed to what happens on screen, so most hits arrive close to their frames and you only fine tune. For single sounds, the free library has thousands of short hits, whooshes and footsteps: 10 free MP3 downloads a month with an account and credit to Sonilo, or unlimited MP3 and WAV on a paid plan.

Any WAV or MP3 works in your editor. Three ways to get one from Sonilo:

• Download it free. The sound effects library has thousands of sounds by category. A free Sonilo account downloads 10 a month as MP3, for videos on your own social channels, monetized ones included, credited “Sound effects by Sonilo” with a link. Paid plans download without limit, in WAV too, for client work and paid ads, with no credit. Take the WAV if you will edit or layer it.
• Describe it. If the library does not have the exact sound, describe it (the material, the action, how it ends) and the sound effects generator makes it in seconds. New accounts get free credits.
• Start from the video. Upload the clip and Sonilo generates sound effects timed to what happens on screen, so most of the placement in the steps above is done before the file reaches your timeline.

Commercial use of audio you generate on Sonilo needs Pro or above; library sound effects download free with an account for your own channels, with credit, and paid plans add client work and paid ads. See licensing for the details.