How to Add Music to a Video on iPhone

The fastest way to add music to a video on iPhone is to add the track in iMovie, then duck it under the voice rather than leaving both at the same level. Here's the full sequence, and the audio work worth doing before you touch a music track at all.

Add music to a video on iPhone with iMovie

Bring your clip into an iMovie project, then use Add Media to add a sound track. A song from your library, or an audio file dropped in from elsewhere. From there it's a balance problem: the music needs to sit under whatever is being said, not compete with it. Placing the track is the easy part; getting the level right against the voice already in the clip is where most edits go wrong.

Getting the voice to survive under the track

The most common failure isn't picking the wrong song. It's a mix where the voice and the music occupy the same frequency range and cancel each other out, so the words become effort to follow without ever being obviously inaudible. Ducking the music down under the spoken parts, deliberately rather than by ear alone, and checking the result on a phone's built-in speaker rather than headphones, is what keeps the voice intelligible once the track is playing underneath it. A mix that sounds balanced on headphones or studio monitors often collapses on a phone speaker, which has far less low end to hide a busy track behind.

The order matters as much as the level. Layering music under a voice that's still noisy or full of pauses means you're now balancing two problems at once. The noise fights the music for the same frequency space, and every gap in the speech becomes an obvious dip in the mix. Sorting the voice out first turns music into a one-step job instead of a repeated one.

Do the voice work first

Montaj doesn't add music, that part still happens in iMovie or wherever you're pulling the track from, and there's no sound library or music picker inside the app. What Montaj takes care of is everything around the voice: transcribing it on your device, generating word-by-word subtitles, removing dead air, and cleaning up background noise, all before the music ever gets layered in. A clean, noise-free voice track is easier to mix music under than a noisy one, which makes this the step worth doing first. Once the voice is right, adding music to a video on iPhone in iMovie is a much shorter job.