Free Online Audio Merger
Add up to 20 files, arrange them, choose a transition between each pair of tracks and download a single WAV file. Everything is processed in your browser.
What Can You Do with the Audio Joiner & Mixer?
- Join files end to end: with No transition, each file starts exactly where the previous one ends. This suits podcast segments, lecture parts and voice takes.
- Choose a transition for every joint: each pair of tracks has its own setting, so one change can be a simple fade and the next a long blend. Eight ready-made transitions are included.
- Build your own transition: Customize opens the three layers a DJ works with: the volume curve, the EQ (when the bass changes over) and filter sweeps.
- Hear each transition on its own: Listen plays from a few seconds before the joint, so you don’t have to play the whole mix to check one change.
- Change the order: move tracks up or down in the list or remove them; the result is rebuilt each time.
The Transitions
| Transition | What happens | Good for |
|---|---|---|
| No transition | The next track starts exactly where the previous one ends | Speech, podcast segments, gapless albums |
| Smooth fade | One track fades out while the next fades in, at constant loudness | Songs with different tempos; any music |
| Warm fade | A smooth fade in which the bass changes over in the middle, so the two bass lines never clash | Pop, rock and soul tracks with strong bass |
| Full blend | Both tracks play at full level; the bass swaps from one to the other in the middle | Dance tracks with the same tempo |
| 3-band blend | Highs, mids and bass change over one after another | Long, gradual blends |
| Build-up | The next track opens up through a low-pass filter while the old one thins out; the bass swaps at the end | Building tension before a drop or chorus |
| Filter wash | The old track sinks behind a low-pass filter as the new one emerges from it | Soft changes between calm tracks |
| Dissolve | The new track fades in thin and fills out; the old one thins out and fades away | Ambient and melodic music |
| Drop | The new track fades in underneath, then the old one is cut at the end | A hard change on a strong beat |
Which Transition and Length Should You Use?
For speech, use No transition, so no words overlap. For songs that have nothing in common, a Smooth fade of 4 to 8 seconds is the safe choice. Blends in which both tracks play at full level work when the tracks have the same tempo; with a length of 16 or 32 seconds they sound like a DJ mix. An overlap is never longer than half of the shorter track. The curves behind the fades are explained in Linear vs. Logarithmic Fades.
Tips for a Mix That Flows
This tool does not change the tempo of your tracks or line up their beats, so the choice of tracks matters. Long blends sound best when neighboring tracks have tempos within a few BPM of each other and keys that go together. You can find the tempo and key of each track with the BPM & Key Analyzer and check which keys are compatible with the Camelot Wheel; How to Pick Songs Like a DJ explains how to put a set in order. When tempos differ a lot, use a short Smooth fade instead of a blend.
Who Is It For?
Podcasters assembling an intro, an interview and an outro, teachers combining lesson recordings, and musicians or fitness instructors building a continuous mix. If you want music to play underneath a voice rather than after it, use the Auto-Ducker instead.