Reverse sound

Sound designers reverse audio because a decay played backwards is a swell. A crash cymbal becomes a rising tension bed. A door slam becomes a vacuum inhale. This page is for those files: short effects, foley, and one-shots, not full albums. The editor is the same Web Audio reverse as the rest of the site.

How a reversed sound behaves

Percussive sounds store most of their energy at the start. After reverse, that energy sits at the end, so the clip starts quietly and explodes. Ambient beds do the opposite if they fade in. Reverb tails turn into pre-verb, which is why reversed vocals in 1980s records feel like they arrive before the word.

If you need that pre-verb on a dry recording, reverse the take, add reverb, bounce, reverse again. That chain is two passes through this page plus a reverb plugin in the middle, or one pass in a DAW. This page only does the reverse step.

Steps

1. Upload a WAV from a library or an MP3 bounce.
2. Play the reversed preview.
3. Check the start and end for clicks. Hard trims in the source become clicks after reverse.
4. Download the WAV and drop it on a timeline.

Preview speeds (0.5x–2x) are for audition. They are not printed into the download. Print speed changes in your editor if you need them.

Library hygiene

Name the export so you do not confuse it with the dry shot (whoosh_reverse.wav). Keep the original. Reversing twice should restore the original shape, but the tool applies a short fade at the edges to reduce clicks, so a round trip is not bit-identical.

For a cartoon rewind button, rewind sound effect covers the extra layers people expect. For musical instruments, reverse singing is the better guide.

Formats

WAV and FLAC keep the transient. MP3 is fine for a sketch. M4A from a phone video is usually the soundtrack plus noise; extract if you only want the effect. See WAV reverser and MP3 reverser for format-specific notes.

Building a reverse swell from a one-shot

Start with a crash, a noise burst, or a vocal “ah” with a long tail. Reverse. The new file should start near silence and grow. If it starts with a bump, the original had noise or a DC offset at the end of the region. Trim the original tail in an editor, re-export, reverse again.

Layer the reversed swell under a forward crash so the swell leads the hit. Line up the reversed file’s end with the crash attack. That alignment is why people reverse cymbals in the first place.

For whooshes, reverse a recording of cloth or traffic, then high-pass in an editor. This page will not EQ. It only flips time.

Foley that does not reverse well

Footsteps become strange suction cups. Keyboard clicks become chirps. Gunshots become odd breaths then a thud at the end. Those can still be useful as alien textures, but they will not read as the original object. Test at 1x before you commit a whole library pass.

Dialogue as “sound” (crowd beds) reverses into unintelligible wash, which is sometimes what you want under a montage. Keep it low in the mix; reversed speech in a crowd can still throw out a recognizable name.

Zero-crossing and clicks

If the source region was cut in the middle of a waveform, reverse puts that open cut at the other end. You hear a tick. Fix: recut on a zero crossing before upload, or accept the tick and fade in the editor after download. The built-in edge fade reduces some of this but will not save a brutal mid-wave crop.

Game and film delivery

Deliver reversed SFX as WAV at the session sample rate, usually 48 kHz. If the browser decoded a 44.1 kHz MP3, resample in the DAW rather than hoping the web export guessed your timeline. Name files with _rev so a sound supervisor can find them.

For a UI rewind control, do not stop at a plain reverse. Designers stack reverse + pitch envelope + tape noise. Start with this reverse, then rewind sound effect for the rest of the recipe. Keep dry and reversed versions in the same folder so a mixer can A/B without guessing names.

Field recording

A reversed field recording is often more useful than a reversed studio one-shot. Wind, rooms, and traffic already contain long tails. Reverse a 10 second bed and you get a strange inhale that still reads as a place. Crop the loudest event (a horn, a shout) off the original end before you reverse, or that event becomes a new attack. Do not publish identifiable voices from a public space without a reason that survives your own ethics pass. The tool will reverse them either way.