Audio joiner
Add two or more audio files, put them in order with the arrow buttons, set a crossfade if you want the end of one track to blend into the next, and download a single WAV. The files are decoded and joined in your browser.
Runs in your browser: nothing you enter is sent anywhere.
How to use it
- Choose several audio files, or add them one batch after another.
- Move them into the order you want with the arrows; remove any you do not need.
- Set a Crossfade in seconds, or leave 0 for a plain join.
- Press Join files, listen to the preview and download the WAV.
How it works
Each file is decoded by the browser into raw samples at 44.1 kHz. The samples are placed one after another into a new buffer; with a crossfade, the overlapping part is mixed with gains that rise from 0 to 1 for the new file and fall from 1 to 0 for the old one, so they always add up to 1. The buffer is then written as a 16-bit PCM WAV file. Nothing leaves your device. The tool joins at most 20 files and up to 10 minutes of audio.
Worked example
A 60 s file and a 40 s file with a 2 s crossfade give a 98 s result: 60 + 40 minus the 2 s overlap. Without crossfade it would be 100 s.
Tips
- A crossfade of 1 to 3 seconds suits music; for speech use 0 or a very short one.
- Join files that were recorded at similar loudness, or the level will jump at the junction.
Frequently asked questions
Which files can I add?
Any audio your browser can decode. That usually means MP3, WAV, M4A/AAC, OGG and often FLAC; the exact list depends on the browser. A file that cannot be decoded is reported and skipped.
What does the crossfade do?
The end of one file fades out while the start of the next fades in over the number of seconds you set, so the junction is shortened by that time. It is limited to half the length of the shorter file. With 0 the files are simply placed one after another.
Why is the result a WAV?
WAV is uncompressed 16-bit audio, which can be written exactly in the browser. It is large: about 10 MB per minute for stereo at 44.1 kHz. Use the audio converter if you need a compressed format.
What happens to files with different sample rates or channels?
Every file is resampled to 44.1 kHz when decoded. If one file is mono and another is stereo, the mono one is copied to both channels.