How to use Audio Merger
- 1Add two or more audio files — they load as separate clips
- 2Reorder them with the up and down controls
- 3Trim each clip's start and end, and set its volume, without leaving the page
- 4Set the junction between any pair: a crossfade of any length and curve, or a gap of silence
- 5Play the merged waveform to check the joins, then export
What Audio Merger does
Joining audio is only trivial when the files already fit together. In practice they rarely do: two recordings made on different days differ in level, tracks butted end to end produce an abrupt seam, and a compilation with no space between pieces sounds relentless. The interesting part of merging is not the concatenation, it is what happens at each junction.
So the junction is treated as a real thing here rather than an afterthought. Between every pair of clips you can set a crossfade of any length, choose the curve it follows, or insert a measured silence instead. The merged result is drawn as a single waveform and plays as one track, so each join can be heard in context before you commit to it.
When to use it
- A continuous mix
- Overlapping each track with the next by a few seconds turns a playlist into a set. Equal-power crossfades keep the perceived loudness steady through the overlap rather than dipping in the middle.
- An interview recorded in parts
- Sessions recorded across several files rejoin with a short gap where the break was. Per-clip volume corrects for a microphone that was moved between takes.
- An audiobook or lecture series
- Chapters merge into one file with a consistent pause between them, which is far easier to navigate on a phone than a folder of separate tracks.
- Layering an intro over music
- Trim each clip to the part you want, set the levels so neither buries the other, and cross the junction with an overlap rather than a hard cut.
Audio Merger settings explained
- Clip order
- Clips merge top to bottom. The up and down controls move one position at a time, and the merged waveform redraws after each move so you can see the new arrangement before playing it.
- Crossfade
- The length of the overlap between two clips, set per junction rather than globally. A second or two suits music; speech usually wants far less or none, because overlapping words are hard to follow.
- Equal power
- The default curve. Fades follow a curve that holds the combined loudness constant through the overlap. This is the correct choice for music, where a linear fade produces an audible dip in the middle.
- Linear
- A straight-line fade. Slightly quieter through the middle of the overlap because two uncorrelated signals at half amplitude do not sum to full loudness, but predictable and fine for speech.
- Hard cut
- No overlap at all — the next clip begins where the previous one ends. Right when the material already ends cleanly, or when any blending would sound wrong.
- Gap
- A measured silence inserted at a junction instead of an overlap. Useful for chapter breaks and between separate pieces, where an overlap would be inappropriate.
- Per-clip trim and volume
- Each clip carries its own in and out points, gain in decibels, and fades. Levels are matched here rather than by editing the source files, so nothing on your device is modified.
Which junction to use
| Junction | Loudness through the join | Best for |
|---|---|---|
| Equal power | Constant | Music, continuous mixes |
| Linear | Dips slightly in the middle | Speech, predictable fades |
| Hard cut | Unchanged | Material that already ends cleanly |
| Gap | Silence | Chapters, tracks, separate pieces |
Limits and what to expect
- 20 tracks per project, 150 MB per file and 400 MB across the whole project.
- All clips are held decoded in memory at once, so a long project consumes far more RAM than the file sizes suggest.
- Clips are mixed to a common sample rate and channel layout; multi-channel surround is folded down.
- A crossfade cannot be longer than the shorter of the two clips it joins.
- Exporting to anything other than MP3 or WAV downloads a ~32 MB engine once, then caches it.
Troubleshooting
- The volume dips in the middle of a crossfade
- That is the signature of a linear curve: two uncorrelated signals at half amplitude sum to less than full loudness. Switch that junction to equal power, which compensates for exactly this.
- One clip is much louder than the others
- Set that clip's gain in decibels rather than re-exporting the source. Around −3 dB is a noticeable reduction and −6 dB is roughly half the perceived loudness.
- The join still sounds abrupt
- A crossfade cannot hide a mismatch in background noise. If two recordings have different room tone, the change is audible however long the overlap. Lengthening the crossfade helps a little; matching the source recordings helps more.
- The project became slow or ran out of memory
- Every clip is stored as uncompressed samples, so an hour of stereo is several hundred megabytes regardless of the compressed size. Merge in two passes — combine half, export, then merge the results.
Your files and your privacy
Every clip is decoded, mixed and exported inside the browser tab using your device's own audio engine. No file is uploaded, no intermediate mix is written to a server, and the preview you hear is played from the same in-memory buffer that will be exported. Closing the tab discards everything.
What to use next
FAQ
How do I merge audio files without a gap between them?
Set that junction to Hard cut, which places the next clip exactly where the previous one ends with no overlap and no silence. If you would rather the two blend, a crossfade of even half a second removes the seam while keeping them effectively continuous.
What is the difference between equal power and linear crossfades?
Both fade one clip down while the other comes up, but along different curves. A linear fade dips in perceived loudness through the middle, because two uncorrelated signals at half amplitude do not sum back to full. Equal power uses a curve that compensates, keeping loudness steady — which is why it is the default for music.
Can I merge files of different formats?
Yes. Every clip is decoded to raw samples first, so an MP3, a WAV and an M4A can be combined in one project. They are mixed to a common sample rate and channel layout, and you choose the output format at export.
How many files can I combine?
Up to 20 tracks within 400 MB. Because decoded audio is held uncompressed, memory is the real constraint — a few long recordings will reach it well before twenty short ones do.
Will merging reduce the audio quality?
The mixing itself is done at full precision and loses nothing. Quality is decided by the export format: WAV or FLAC preserve the mix exactly, while MP3 or AAC re-encode it. If the sources were already lossy, the export is a second generation regardless.
Can I change the order after adding files?
Yes, at any point before exporting. The up and down controls reorder clips, and the merged waveform and preview rebuild immediately so you can hear the new arrangement.