How to Overlap Audio Files Online — Layer Music, Voice and Effects (Free)
Layer two or more audio files so they play at the same time: music under a voiceover, effects over a podcast, a beat under vocals. Drag each track into place, set its volume, export MP3, AAC, WAV or OGG.
The 60-second version
Open Overlap Audio Files (it’s the same mixer as Mix Audio), add your files (each becomes its own track), drag the tracks along the timeline to where each should start, lower the music under the voice, and click Process. Two tracks at once are free with no watermark; paid plans can stack as many as they like.
Overlap, mix, or join? Pick the right job
Three jobs sound alike but aren’t:
- Overlap / mix — tracks play at the same time: music under a voiceover, a beat under vocals, sound effects over a podcast. That’s Mix Audio.
- Join — tracks play one after another: podcast segments, audiobook chapters, a playlist in one file. That’s Audio Joiner.
- Trim — keep only part of one track. That’s Cut Audio, and it’s often the step before a good overlap.
Most people who search for “overlap audio” want the first one.
Step by step
- Add your files. Each one drops in as its own track. MP3, WAV, AAC, FLAC, OGG and M4A all work.
- Line them up. Drag a track along the timeline to set when it comes in: start the music a few seconds before the voice for an intro, or drop an effect exactly on a word.
- Trim and balance. Pull a track’s edge handles to trim it, and set each track’s volume on its own. A voice usually needs to sit clearly above the music; start with the music low and raise it until it’s just audible under the speech.
- Preview. The live waveform lets you hear the layered mix before you export.
- Export. MP3, AAC, WAV or OGG in your browser; FLAC on our servers.
Each track keeps the volume you give it. Many mixers divide the level by the number of tracks, which would drop two layered tracks to half volume each; this one doesn’t.
How long is the result?
As long as the longest track, counted from where it sits on the timeline. A 10-second effect dropped at 2:00 into a 3-minute song gives a 3-minute file; drop the same effect at 2:55 and the file runs to 3:05.
Tips for a clean mix
- Voice over music: keep the voice the loudest thing in the mix. Your ear gets used to a loud music bed while you edit, so trust a second listen the next day more than the first.
- No ducking yet: the mixer doesn’t lower the music automatically while someone talks. You can get close by trimming the music into pieces that only play in the pauses, or by keeping it low throughout.
- Export format: WAV if the mix is going back into an editor (no extra compression), MP3 or AAC for sharing. Mixing files that are already MP3 and exporting to MP3 again compresses twice, which you can hear on cymbals and speech.
- Need a music bed? The free music library has royalty-free tracks you can drop in as a layer, and Sound Effects has whooshes, hits and risers.
Which tool for which job
| Job | Tool |
|---|---|
| Podcast with an intro and outro under the voice | Mix Audio, 3 tracks |
| Vocals over an instrumental | Overlap Audio Files, 2 tracks |
| Game audio plus commentary | Overlap Audio Files, 2 tracks |
| Voice over an ambient loop | Mix Audio, 2 tracks |
| Songs back to back in one file | Audio Joiner |
In other languages
FAQ
Is it free? Layering two tracks at once is free with no watermark, and it runs in your browser, so your files stay on your device. Three or more tracks at once need a paid plan.
What formats work? In: MP3, WAV, AAC, FLAC, OGG and M4A. Out: MP3, AAC, WAV and OGG, plus FLAC on our servers.
Can I put audio over a video instead? Yes, but that’s a different tool: Add Music to Video keeps the video and lays a track under or over its sound.
Can I hear it before exporting? Yes. The preview plays the layered mix in your browser before you export.