Reverse Audio

Reverse Audio is a free online tool that plays any audio file backwards. Upload the audio, listen to it reversed right away, compare it with the original and download the reversed audio as a WAV file.

Your file is never uploaded anywhere: it is read, reversed and played inside your own browser.

How to use this online tool?

1. Upload the audio file you want to reverse.
2. Press play on the "Reversed audio" player to hear it backwards.
3. Press play on the "Original audio" player whenever you want to compare it with the original.
4. Click anywhere on a waveform to jump to that point of the audio.
5. Click "Download" to save the reversed audio as a WAV file.

What can you use it for?

• Creating reverse sound effects, like the reversed cymbal or the reversed piano note that swells up into a beat.
• Making eerie and ghostly voices for videos, games and haunted house soundtracks.
• Searching for hidden messages, the famous backmasking that some songs are said to carry when played backwards.
• Playing the reverse singing game: record a phrase, reverse it, try to imitate the reversed audio, then reverse your imitation and see how close it gets to the original.
• Checking palindromes, words and phrases that sound (almost) the same forwards and backwards.
• Exploring sounds in a different way: speech, music and noises all reveal new textures when played backwards.

How is the audio reversed?

A digital audio file is a long list of numbers, called samples, each one telling how far the speaker should be pushed at a given instant. A CD quality recording has 44,100 of them per second for each channel. Reversing the audio simply means reading that list from the last sample to the first one. Every channel is reversed at the same time, so a stereo recording keeps the left on the left and the right on the right.

Nothing else changes: the duration, the pitch and the volume of the reversed audio are exactly the same as the original. What changes is the shape of each sound in time. A piano note normally starts with a sharp attack and fades out slowly; played backwards it fades in slowly and stops abruptly, which is the typical "sucking" sound of reversed audio. For the same reason, if the original file ends with a few seconds of silence, the reversed one starts with that silence.

Which files can I use?

Anything your browser is able to play: MP3, WAV, OGG, M4A, AAC, FLAC, WebM, Opus and so on. The tool decodes the file with your browser's own audio decoder, so the exact list depends on the browser you are using. The result is always saved as a WAV file, which is uncompressed: it keeps the full quality, but it is considerably bigger than an MP3 of the same audio.

Is my audio uploaded to a server?

No. This tool has no server side at all. Your file is read by the browser, decoded by the browser, reversed by the browser and saved by the browser. It never leaves your computer, which also means the tool keeps working if you lose your connection after the page has loaded.