How to create a backwards audio effect online — free
- Step 1Bounce or export the stem you want reversed — Export the element — a cymbal hit, a vocal phrase, a pad — from your DAW, ideally as WAV or FLAC so the reversal stays lossless. Then drop that single file onto the reverser.
- Step 2Confirm the stem details — The file card shows sample rate, channels, and duration. Stems are usually short, so the free-tier 30-minute / 50 MB limits are rarely a concern for individual elements.
- Step 3Press Run Reverse — FFmpeg WASM runs
-af areverseand re-encodes to the stem's format with the matching codec (pcm_s16lefor WAV,flacfor FLAC). No options to set. - Step 4Audition the reversed stem — The result card embeds a player. Listen for the reversed envelope — the natural decay now becomes an attack, which is exactly what makes reverse cymbals and risers work.
- Step 5Download and drop it back on the timeline — Save
stem-reversed.<ext>and import it into your DAW. Line up the reversed element's new transient (formerly its tail) with the target downbeat. - Step 6For reverse-reverb, run a second pass — Reverse the stem, add reverb in your DAW on the reversed version, then bring that wet file back here and reverse again. The result is reverb that swells into the note instead of trailing after it.
Backwards-effect cookbook (technique map)
Common production effects and how the reverser fits each one. Reverb and EQ steps stay in your DAW.
| Effect | How reversal is used | Tip |
|---|---|---|
| Reverse cymbal / crash riser | Reverse a cymbal/crash WAV so its decay becomes a build-up | Align the reversed peak (was the tail) on the downbeat |
| Reverse-reverb vocal swell | Reverse dry vocal → add reverb in DAW → reverse again | Two passes here, reverb in the DAW between them |
| Backwards pad / texture | Reverse a sustained pad for an evolving, sucking-in texture | Add fade-in-out to taper edges |
| Tape-stop flip | Reverse a phrase, then slow it with tempo-changer | Combine with pitch dip for the tape feel |
| Reverse vocal chop FX | Trim a syllable, reverse it, drop it as an ear-candy hit | Use audio-trimmer for the chop |
Quality and limits for stems
Format outcome and tier caps relevant to production stems.
| Stem format | Reversal quality | Free-tier cap |
|---|---|---|
| WAV | Lossless (exact mirror) | 50 MB / 30 min |
| FLAC | Lossless (exact mirror) | 50 MB / 30 min |
| MP3 bounce | One lossy re-encode | 50 MB / 30 min |
| M4A / AAC | One lossy re-encode | 50 MB / 30 min |
Cookbook
Production recipes for the backwards effect. The command shown is the WASM invocation; you just press Run.
Reverse cymbal into a downbeat
Reverse a crash WAV so its long decay becomes a swell that resolves on beat 1. Keep it WAV for lossless quality.
Input : crash.wav Run : ffmpeg -i crash.wav -af areverse -c:a pcm_s16le out.wav Output: crash-reversed.wav (place its peak on the downbeat)
Reverse-reverb vocal swell (3-pass)
The signature swell-into-the-word effect. The reverser handles passes 1 and 3; the reverb is your DAW's job in pass 2.
1. audio-reverser vocal.wav -> vocal-reversed.wav 2. (DAW) reverb on vocal-reversed.wav -> wet.wav 3. audio-reverser wet.wav -> wet-reversed.wav Now the reverb builds UP into each word, then snaps to the dry note.
Backwards riser from a pad
Reverse a sustained pad and taper its edges to make a clean riser into a section.
Step 1 audio-reverser pad.flac -> pad-reversed.flac (lossless) Step 2 fade-in-out -> short fade on each end (/audio-tools/fade-in-out) Step 3 drop before the drop; its rising energy leads the section
Reverse vocal chop ear-candy
Cut a single syllable, reverse it, and use it as a transition hit.
Step 1 audio-trimmer -> syllable.wav (/audio-tools/audio-trimmer) Step 2 audio-reverser -> syllable-reversed.wav Step 3 optionally pitch-shifter for a tuned FX (/audio-tools/pitch-shifter)
Tape-stop flip
Reverse a phrase then slow it for a backwards tape-stop feel.
Step 1 audio-reverser phrase.wav -> phrase-reversed.wav Step 2 tempo-changer to ~70% -> slowed (/audio-tools/tempo-changer) (Add a downward pitch ramp in your DAW for the classic tape sag.)
Edge cases and what actually happens
Reversed cymbal peak doesn't land on the beat
AlignmentReversal moves the loudest moment (the original attack) to the very end. Line up the reversed file's new peak — which was the original's decay tail — with your downbeat. Nudge in your DAW; the tool does not time-align for you.
Expected reverb but got a dry reversed file
By designThe reverser does not add reverb — it only reverses. Reverse-reverb is a three-pass technique with the reverb applied in your DAW between the two reversal passes. The tool faithfully handles both reversal passes.
Reversing an MP3 bounce instead of a WAV stem
Expected (lossy)If you bounce the stem to MP3 first, reversal re-encodes lossily (one generation). For production, bounce stems to WAV or FLAC so the reversal stays lossless and clean in the chain.
Output sample rate matches the stem, not the project
PreservedReversal preserves the input sample rate exactly — it does not resample to your project rate. Bounce the stem at your project's rate (e.g. 48 kHz) so the reversed file drops in without a sample-rate conversion. Use sample-rate-converter if you need to change it.
Stereo image seems mirrored after reversal
PreservedChannels are preserved — L stays L, R stays R; only the time axis flips. If the image feels different, it is because the stereo *movement* now plays in reverse, not because channels were swapped.
Tried to reverse multiple stems at once
Single file onlyThe reverser is single-file. Reverse each stem separately. To reverse a printed mix of several stems together, render them to one file first or use audio-merger.
Want it reversed AND in a different format
By designOutput format equals input format. Reverse the WAV stem (lossless), then convert with a sibling converter such as wav-to-flac or wav-to-mp3 afterwards.
Clicks at the edges of the reversed clip
Edit hygieneA non-zero-crossing cut can click when reversed because the former end becomes the start. Add a tiny fade with fade-in-out or trim to a zero crossing with audio-trimmer before reversing.
Frequently asked questions
Is the backwards effect lossless on my stems?
For WAV and FLAC stems, yes. Reversal is an exact sample-by-sample mirror, and the re-encode uses a lossless codec (pcm_s16le for WAV, flac for FLAC), so the reversed stem is bit-equivalent to a manually reversed original. Only lossy sources (MP3, M4A, OGG, Opus) incur a re-encode generation. Bounce stems to WAV/FLAC for production work.
How do I make a reverse-reverb swell?
It is a three-pass technique. (1) Reverse the dry stem here. (2) In your DAW, apply reverb to the reversed file. (3) Reverse that wet result here again. The reverb then swells up into the note instead of trailing after it. This tool handles passes 1 and 3; the reverb step stays in your DAW because the reverser does not add reverb.
Does reversal keep my stem's sample rate?
Yes — sample rate, bit depth context, channel count, and duration are all preserved. Reversal only reorders samples. Bounce the stem at your project's rate (e.g. 48 kHz) so the reversed file drops straight back on the timeline. Use sample-rate-converter if you need a different rate.
Will reversing change the stereo image or channels?
No channel swap occurs — left stays left, right stays right. Only the time direction flips, so any panning automation or stereo movement now plays in reverse, which is usually the desired creative result.
Can I reverse just one syllable or hit?
Yes — trim it out first with audio-trimmer, then reverse the short clip. Reversal always acts on the whole file you give it, so isolate the element first.
Are my unreleased stems uploaded anywhere?
No. Reversal runs in your browser via FFmpeg 8.1 WebAssembly. Stems are processed locally and never transmitted, which is essential for unreleased material and client work.
Can I combine reversal with pitch or tempo changes?
Yes, in steps. Reverse here, then use pitch-shifter for tuned reverse FX or tempo-changer / time-stretcher for tape-stop and slowdown effects. Each tool runs one transform; chain them in the order you want.
Why does my reversed cymbal click at the start?
The original tail becomes the new start, and if that point isn't at a zero crossing it can click. Add a very short fade with fade-in-out, or trim to a zero crossing before reversing.
Can I reverse multiple stems in one go?
No — the reverser processes one file per run. Reverse each stem individually. To reverse a combined element, merge first with audio-merger and reverse the single result.
Does it change the output format of my stem?
No — it keeps the input format. A WAV stem comes back as WAV. If you want the reversed stem in another format, convert afterwards with a sibling converter like wav-to-flac.
How long can a stem be?
Up to 30 minutes / 50 MB on the free tier — far more than any single stem usually needs. Pro raises it to 120 minutes / 200 MB for long printed sections or full reversed mixes.
Does reversing add latency or change duration?
No. The reversed file has exactly the same duration as the original; reversal only flips sample order. There is no added silence or latency.
Privacy first
Every JAD Audio tool runs entirely in your browser via FFmpeg (WebAssembly) and RNNoise. Your audio files never leave your device — verified by zero outbound network requests during processing.