Merge audio
What Merge audio actually does
Joining files is an ordering job, and most joiners treat the order as whatever the file picker handed over. This page puts every file on one timeline at one shared amplitude scale, so a track that is quieter than the rest is visible before anything is rendered, and the order is moved with buttons rather than only by dragging. A crossfade overlaps each join, which makes the result shorter than the sum of the parts by one overlap per join; the page states the length the settings predict and then, after the render, the length the finished file actually has.
How to use it
- Choose two or more files. Each one is decoded in this tab and drawn as a track on the shared timeline.
- Move tracks up and down until the order is the one you want, and set a crossfade if the joins should overlap.
- Join them, then compare the predicted length against the length read back from the produced file.
Useful for
- Assemble interview segments or takes into one continuous recording.
- Build a continuous set from separate tracks with a crossfade at each change.
- Concatenate chapters into a single long file for a player that has no queue.
Limits worth knowing
- A crossfade at or past the whole length of the shortest file is refused by name, because the overlap would consume that file entirely and the result would be shorter than the inputs.
- Every input is converted to a common sample rate and channel count before joining, taking the highest of each, so a mono file in a stereo set is upmixed.
- Trimming inside a track belongs to the trim tool; this page joins whole files.
Questions people ask
Are the files uploaded?
No. Decoding, drawing and joining all happen in this tab. The audio engine is fetched once and cached.
Why is the result shorter than the sum of the files?
A crossfade overlaps the end of one file with the start of the next, so each join gives up that much time. With no crossfade the result is the exact sum.
Can the order be changed after adding files?
Yes. Each track has up and down controls, and the timeline redraws in the new order.