Give it the layers a commercial mixer would. A steady ambience bed under each location, sync sounds for every product action (caps, pours, clicks, engine starts) and a few design hits on cuts and the logo reveal, all sitting under the voiceover and music. Deliver stems so the final mix can be balanced against both.

Why does my AI ad sound unfinished?

Every clip has sound. The spot doesn't. Several video models now generate audio with each shot: Veo 3.1, for example, generates 4- to 8-second clips with audio always on. Each clip's track is mixed on its own, so a 30-second spot cut from them changes room at every edit. The product sounds are whatever the model chose for that shot, and you end up with one mixed track per clip and nothing you can balance under a voiceover.

That native audio is useful for a single shot or a rough cut. A commercial needs its sound designed across the whole spot, so the edit plays as one piece.

What sounds does a product shot need?

The product is the hero, so it gets the closest, cleanest sounds in the spot. Spot every action the product makes, and every action a hand does to it:

Contact: the cap twist, the lid pop, a case clicking shut, a phone set down on a table.
Liquid and food: the pour, the fizz, ice in a glass, the crunch of a first bite.
Machines: the key fob chirp, the door thunk, the engine start, the button press.
Hands and cloth: a sleeve brushing past, a grip tightening on a bottle.

Commercial foley is bigger and closer than real life. A pour in a 30-second spot sounds as if the microphone sat inside the glass. Put each sound on the frame where the action happens, and clear away anything that competes with it. If the hero shot is a bottle opening, the room behind it should drop back for that moment.

How should the ambience work across cuts?

One bed per location. If the spot cuts between a kitchen and a street, the kitchen keeps the same room tone every time you come back to it, and the street keeps its traffic. Change the bed only when the place changes.

Keep it low and simple. Under a voiceover, ambience is there to tell the viewer where they are. A busy bed fights the voice for the same space in the midrange.

This is where stitched AI clips fall apart first, because each generated shot invents its own background. Muting the clips' own audio and laying one continuous bed per place fixes most of it.

Where do impacts go in a 30-second spot?

Fewer places than you think. As a starting point, plan three to five design hits in 30 seconds. Past that, none of them land. A typical map:

The first frame. Start on a sound: a sync hit on the first action, or a short whoosh into the first shot. The opening second has to earn the next one.
Cuts that move. A whoosh belongs on a whip pan, a product swipe or a fast push-in. On a plain cut, let the change of ambience do the work.
The reveal. The hero shot gets the biggest moment: a riser into it and an impact on the frame where it lands, then clean product sounds on top.
The logo or end card. One final hit or swell, timed with the music's last beat so the two don't fight. If the music already lands hard, leave the design out.

Put hits in the gaps between voiceover lines, never on a key word. And volume won't rescue a weak moment. For US television, the FCC's rules under the CALM Act hold a commercial's average volume to the level of the programs around it. Impact comes from contrast, so give the big hit a beat of quiet before it.

How do I leave room for the voiceover and music?

Build the sound design to sit underneath both. Keep beds quiet and steady under lines. Hold back design hits where the music has its own accents.

Most of all, keep the layers separate. When ambience, actions and design arrive as their own stems, whoever mixes the spot can pull the ambience down under a line, or mute the design during a music build, without touching the rest.

What do I hand the client?

It depends on who finishes the mix:

A review copy: a QuickTime with the full mix, so the client hears the spot as intended.
Stems: one WAV per sound category (ambience, actions, design), so the mixer can balance them against the voiceover and music.
An AAF: the multitrack timeline, for a mixer or editor working in Premiere Pro or another editing app.

Ask for the delivery spec before the final mix. Broadcasters, platforms and agencies set their own loudness targets and file formats.

How do I do this with Effct?

Effct does the first pass of the sound design across the whole spot. You make the calls.

Lock the cut and upload it. MP4, MOV, AVI, MKV or WEBM. Effct analyzes the picture frame by frame. On paid plans, Include existing audio on New Project is on by default; untick it to drop the clips' own sound.
Let Effct place the first pass. It places ambience for each location, action sounds for what happens on screen, and whooshes, impacts and risers on cuts and reveals. The sounds come from its library of team-recorded and CC0 recordings, placed in sync and mixed.
Fix the product moments. Every sound is its own clip. Drag a hit onto the exact frame, drag its edges to trim it, or choose Regenerate for new options. If a product sound is missing, add one by describing it ("soda can opening", "car key fob chirp") and Effct finds a match in its library.
Balance for the voice. Select a clip and press the up or down arrow to change its volume in 2 dB steps. Use Category Levels to pull the ambience down, or solo the design layer to count your hits.
Export. QuickTime with the mix on every paid plan, WAV stems on Creator ($29 a month) and up, and AAF on Pro ($49 a month) and up. Exports follow the mix you hear in the editor.

There's more on each editing step in how to edit the sounds Effct places, and on spots in particular on the commercial sound design page.

What Effct does and doesn't do

Effct places and mixes the sound design: ambience, actions and design sounds. It doesn't make music, and the voiceover usually comes from you or your client; the stems leave room for both.

Try it free on your own video: Effct sound-designs the first 30 seconds of one video, previewed in the editor. No credit card. The trial places ambience and design sounds; action sounds come with a paid plan.

Last updated October 2026.

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