How do I add sound effects to a Kling, Veo or Seedance video?

Finish the edit, then add sound to the whole cut. Kling, Veo and Seedance make audio separately for every clip, so a stitched film can change room at every cut. Upload the finished cut to a sound design tool like Effct, which places ambience, effects, whooshes and impacts in sync across the video, each on its own clip.

Why not just use the sound the clips came with?

For a single shot, you often can. All three tools now make sound with the picture. Google's Veo 3.1 makes clips of 4, 6 or 8 seconds with sound generation built in (Vertex AI docs). Kling 3.0 makes clips of up to 15 seconds with native audio. Seedance 2.5 makes up to 30 seconds of audio and video in a single pass (ByteDance Seed). Inside one generation, the sound usually fits the picture and lands in sync.

The trouble starts when you cut generations together. Unless you extend from the previous clip or give the model reference audio, each clip's sound is made on its own. Two shots of the same street can come back with different traffic, a different hum, music in one and nothing in the next. On screen it's one street. On the soundtrack it's two.

The sound also arrives mixed into the clip, so keeping the footsteps while losing the background takes extra work. And nobody spotted the film as a whole. The cut from the alley to the rooftop gets whatever each clip happened to make, instead of a whoosh or an impact chosen for that moment.

How do I add sound effects to a whole AI film?

This is the pass a sound editor would make. It works in Premiere Pro, Resolve, CapCut or any editor with a few audio tracks.

1. Lock the edit. Sound follows picture. Every trim after this moves your hits off their frames.
2. Decide what stays from the clips. Keep any generated dialogue you want. Mute or pull down the rest of the native audio so it doesn't fight what you add.
3. Lay ambience by place. Run one continuous bed under every shot in the same location, and change it only when the scene moves. Crossfade over a few frames at each change so it doesn't click.
4. Spot the actions. Watch for anything on screen that would make a sound: footsteps, doors, cloth, cars, a glass set down. Sync each one to the frame of contact.
5. Add design sounds where the edit needs a push. A whoosh into a fast cut, an impact on a hit or a title, a riser before a reveal. A few well-placed hits feel cinematic. One on every cut feels like a parody trailer.
6. Mix. Ambience sits low and steady. Actions sit where you'd hear them in the room. Design hits come forward for a moment, then get out of the way. Leave space for music and voiceover if you're adding them.
7. Export in layers. Keep ambience, actions and design as separate files so you can rebalance them against music later.

Steps 3 to 5 are where the hours go: finding each sound in a library, then nudging it onto the right frame, dozens of times per film.

Can a tool do the first pass for me?

Yes. Effct does the spotting, placing and first mix from your upload, then hands you the result as clips you can change.

1. Upload the finished cut. MP4, MOV, AVI, MKV or WEBM. A project covers up to 20 minutes; longer videos are split into 20-minute projects.
2. Effct analyzes the picture frame by frame. It places three layers from its library of team-recorded and CC0 sounds: ambience, actions (footsteps, doors, cloth, cars) and design sounds (whooshes, impacts, risers). It places them in sync and mixes them.
3. Review and make your calls. Every sound is its own clip. Drag a clip to move it, drag its edges to trim it, or choose Regenerate to hear new options. Add a sound by describing it and Effct finds a match in its library. The up and down arrow keys change a clip's volume in 2 dB steps, Category Levels set the level of ambience, actions and design (with mute and solo), and Delete removes a clip.
4. Export. The export follows the mix you hear in the editor.

Spend your review time on the scene changes and your biggest cuts. That's where your taste matters most.

Should I keep the clips' own audio?

Keep it when the clips carry something you can't replace: a line of generated dialogue, a lip-synced performance, or a sound the model got exactly right. Drop it when it's mostly background, because mismatched beds are what make a stitched film sound stitched.

In Effct, Include existing audio on New Project brings the video's existing audio into the project on paid plans. It's on by default; untick it and Effct builds the sound design without it. The free trial always leaves it out. Effct doesn't make dialogue, so if your film needs speech, it has to come from your clips or a separate recording.

What about a single clip?

If you're posting one 8-second shot, the native audio may be all you need. Generate it again until the sound fits, or try Kling's Video-to-Audio tool, which analyzes the movement in a clip and makes matching sound (Kling's guide). Designing the whole cut pays off from the second clip on, once the sound has to carry across cuts.

How do I get stems out?

The video tools hand you each clip with its sound already mixed in. To work in layers, rebuild the sound design on separate tracks, by hand or with Effct. Effct exports by plan:

• QuickTime (.mov) with the full mix: every paid plan, from Starter at $12 a month.
• WAV stems, one per sound category: Creator ($29 a month) and up.
• AAF for Premiere Pro and other editors: Pro ($49 a month) and up.

See plans and minutes.

Can I do this inside Premiere Pro?

Yes, if you cut in Premiere Pro 25.6 or later and have a paid plan. The panel works from one video clip, so export the finished cut as a single file and make a sequence from it with New Sequence From Clip. Then in the Effct panel click Load Sequence, then Add Sound Design. The clips land on new audio tracks, and the files go into an "Effct Audio" bin. Get the panel on Adobe Exchange.

What Effct does and doesn't do

Effct places and mixes sound design (ambience, actions and design sounds) from its library of recorded sounds. It doesn't make music.

Try it free on your own video: Effct sound-designs the first 30 seconds of one video, previewed in the editor. No credit card.

Last updated October 2026.