At a glance
| Input | Any audio the browser can open, several files at once |
|---|---|
| Output | One MP3 or WAV |
| Where it runs | Entirely in your browser — no file is uploaded to a server |
| Price | Free, with no account and no sign-up |
| Offline | Works with no connection after the first visit |
Different sources rarely match
Files recorded at different times are usually at different volumes, and joining them produces something a listener has to keep adjusting. Levelling them before joining matters more than any other single step.
Sample rates differ too — 44.1kHz for music, 48kHz for video audio, sometimes 16kHz for voice recordings. They are resampled to a common rate here, because a mismatch otherwise plays at the wrong speed.
Crossfades and gaps
A hard join between two tracks is abrupt and, if either ends mid-waveform, audibly clicks. A short crossfade — half a second is plenty — removes both problems.
For an audiobook or a podcast assembled from segments, a brief silence between parts reads as a paragraph break and is worth more than a seamless join.
Frequently asked questions
Why do the volumes jump between tracks?
They were recorded at different levels. Level them before joining — it makes more difference to the result than anything else.
Do the files need to be the same format?
No. Different formats and sample rates are decoded and resampled to a common rate, which is what stops a mismatch playing at the wrong speed.
Should I add a crossfade?
For music, yes — half a second removes the click and the abruptness. For spoken segments, a short silence usually reads better.
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