Audio Reverser

What reversing does to a sound

Reversing plays the samples back in the opposite order, last to first. It is a lossless operation in the mathematical sense — no information is discarded — but it changes the character of a sound completely, because almost every natural sound has an asymmetric envelope. A piano note starts with a sharp hammer strike and decays slowly. Reversed, it swells from nothing into an abrupt stop, which is why reversed instruments sound so distinctively unnatural.

Reverb reverses too, and that is where most of the interest lies. Forward, reverb trails behind a sound. Backward, it rushes in ahead of it. That pre-echo effect is the basis of the reversed-cymbal swell used to lead into a chorus, and of a great deal of ambient and psychedelic production.

What people use it for

• Transitions — a reversed cymbal or vocal phrase makes a natural build into the next section of a track.
• Sound design — reversing a door slam, a match strike or a splash produces something recognisable but unplaceable, which is exactly what you want for effects.
• Checking a lyric — reversing a passage to hear what a mumbled line actually is, which works better than repeated forward listening surprisingly often.
• Practice — musicians sometimes reverse a phrase to learn it from the other direction, which forces attention onto intervals rather than muscle memory.

Reversing part of a file

This tool reverses the whole file. To reverse just a section, cut that section out with the MP3 Cutter first, reverse the result here, then put it back where you want it with the Audio Joiner. It is three steps rather than one, but it keeps each tool doing a single job and the intermediate files are exact if you keep them in WAV or FLAC.

Export in a lossless format if the reversed clip is going into further production. Reversal is applied on the server when you export and the uploaded file is deleted as soon as the download finishes.