Upload the clip
A vocal phrase, a crash, or a chord works best. Short clips are easier to place than whole tracks.
Free online tool
Reverse Reverb
Pre-Verb Generator — Make Reverb Swell Into the Sound
Upload audio and get the reverb tail arriving before each sound instead of after it — the swell producers build by hand in a DAW, done in one pass. Free, no signup, runs in your browser.
Free online toolNo signupWorks in browserMP3, WAV, FLAC, OGG supportedPrivate browser-based processing
Upload Audio
Drag and drop your audio here, or click to browse. Supports MP3, WAV, FLAC, OGG, and M4A input files.
Swell length 0.3–5.0s, reverb amount 0–100%
Presets: Vocal Swell, Riser, Cinematic, Subtle Lift
Preview, Download MP3, Download WAV
⏪ Want the audio itself backwards rather than just the reverb? That is the Reverse Audio tool.
Open Reverse Audio →How to Make Reverse Reverb
Set the swell length
This is how far ahead of the sound the reverb starts building. Two to three seconds suits most vocals.
Set the reverb amount
High for risers where the swell is the point; lower when the dry sound still has to carry the phrase.
Export and place it
The file gains the swell length as lead-in. Drag it in your editor so the swell resolves on the downbeat.
Best Reverse Reverb Settings
Swell length is the setting that decides what the effect is for. Reverb amount just decides how loudly it announces itself.
| Preset | Settings | When to Use |
|---|---|---|
| Vocal Swell | 2.0s · 60% wet | Lifts into a vocal line. The standard use, and the one most records use it for. |
| Riser | 3.5s · 80% wet | Builds into a drop or chorus. Place it so the swell ends exactly where the section starts. |
| Cinematic | 5.0s · 90% wet | A long rise for trailers and intros. Almost entirely swell, with the dry sound as the resolution. |
| Subtle Lift | 1.2s · 40% wet | Barely noticeable on its own — adds anticipation without announcing itself. |
Why Use This Reverse Reverb Tool?
The tail actually comes first
Not reverb with a reversed character — the swell genuinely precedes the sound, which is the whole point of pre-verb.
One pass, no bouncing
The DAW recipe is reverse, reverb, render, reverse back. Here it is a single render with nothing to re-import.
Lead-in handled for you
The export is extended by the swell length, so the build is never clipped off the front of the file.
Adjustable swell length
From a 0.3s lift to a 5s cinematic rise, previewed live before you commit.
No signup, no watermark
Use it in your browser and keep the full-length export.
Private processing
Your audio is processed on your device rather than uploaded to a server.
How a Sound Arrives Before Itself
Ordinary reverb is causal: a sound happens, and the room answers. Every reflection arrives after the thing that caused it, because that is how rooms work. Pre-verb breaks that, and the reason it feels dramatic is precisely that it cannot physically happen — your ear hears a space responding to something that has not occurred yet, so it reads the arrival as inevitable.
The studio method is a workaround for the physics. You flip the clip so the future becomes the past, let the reverb trail off normally in that flipped world, then flip everything back — and the trail is now a build. The mathematics is neater than the workflow: reversing both the input and the output of a reverb is the same as leaving the audio alone and reversing the reverb instead. That is what this tool does, which is why there is no bouncing and re-importing, and why the preview is exactly what you download.
One consequence is unavoidable and worth expecting: the swell needs somewhere to live, and that place is before your audio starts. The export is therefore longer than the file you uploaded by exactly the swell length you chose. That lead-in is the effect, not padding.
Placing the Swell So It Lands
A pre-verb that is not aligned to anything just sounds like a wash. The effect works when the swell resolves — when the peak of the build coincides with the moment you want to emphasise. In practice that means dragging the exported clip earlier in your timeline until the dry sound sits on the downbeat, letting the build occupy the bar before it.
For risers into a drop, the same rule applies with a longer swell: place it so the build ends exactly where the new section begins, not a beat after. For vocals, a phrase starting on a vowel gives the swell something smooth to resolve into — a hard consonant cuts the build off rather than completing it. And keep the untreated original in the mix underneath if you still need the words intelligible; the swell is an addition, not a replacement.
More Free Audio Tools
Reverse Audio
Play a whole track backwards — the other half of the reversing toolkit.
Slowed Reverb Generator
Ordinary reverb that trails after the sound, plus speed control.
Volume Booster
Level a swell against the rest of your mix without clipping.
8D Audio Converter
Spin the result around the listener's head for headphones.
Muffled Song Maker
Push a sound behind a wall instead of ahead of itself.
Reverse Reverb FAQ
What is reverse reverb?
Reverse reverb, often called pre-verb, is reverb that arrives before the sound instead of after it. Instead of a note ringing out into a room, the room builds up first and the note lands at the peak of it. It is one of the oldest tricks in record production and it is still the standard way to make a vocal line or a drop feel inevitable.
How is this different from just reversing audio?
Reversing plays the whole recording backwards — the words come out in the wrong order. Reverse reverb leaves the sound completely forwards and untouched; only the reverb around it is flipped. If you want the actual audio backwards, that is the reverse audio tool. If you want the sound normal with a swell leading into it, this is the one.
Why is my exported file longer than the original?
Because the swell has to happen before the first sound, and there is nowhere to put it inside the original length. The export is extended by exactly the swell length you set, so a 2-second swell adds 2 seconds of build at the front. That lead-in is the effect. Drag the clip earlier in your editor until the swell resolves where you want it.
How long should the swell be?
Two to three seconds covers most vocal work — long enough to feel deliberate, short enough not to smear the phrase before it. Four to five seconds turns it into a cinematic rise, which suits trailers, intros, and builds into a drop. Under about a second reads as a lift rather than a swell, which is useful when you want anticipation without anyone noticing why.
How do producers normally make this in a DAW?
Four steps: duplicate the clip, reverse it, print reverb onto the reversed version, then reverse the result back. Two details decide whether it works. You must render the reverb to audio before the second reversal, because a live plugin cannot be played backwards. And you must leave silence after the reversed clip so the tail has room to decay — that silence becomes the swell's lead-in when you flip it. This tool does the whole chain in one render.
What material works best for reverse reverb?
Anything with a clear beginning to build toward. Vocal phrases are the classic choice, and a phrase starting on a vowel gives the swell something smooth to resolve into. Crashes and cymbals make natural risers. Sustained chords work well for trailers. Dense, continuous material works least well, because there is no single moment for the swell to point at.
Which records use reverse reverb?
It has a long pedigree. Reverse echo appears on Led Zeppelin's "Whole Lotta Love" and Genesis's "Deep in the Motherlode," and the vocal on Metallica's "Fade to Black" is a well-known example. Who invented it is genuinely disputed — Jimmy Page claimed it for his Yardbirds work, and other accounts credit different producers working around the same time — so treat any confident single-origin story with suspicion.
Can I use reverse reverb on a whole song?
You can, but it rarely sounds good. Applied across a full mix every sound gets a swell, and they overlap into a continuous wash that blurs the rhythm. The effect works because it is an event — a build pointing at one moment. Use it on a clip, then place that clip against your untreated track rather than treating everything.