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Reverse audio.
Backwards, and nothing else changed.
Play any file back to front and download it lossless. The operation is trivial and the useful part is what it exposes: a reversed file puts the old ending at the new beginning, which is where a DC offset stops being inaudible and starts being a click on every play. So that gets measured.
Drop tracks to reverse
WAV, AIFF, FLAC, MP3 or M4A. Drop a whole folder’s worth — one set of settings is applied to all of them and they come back as a single archive. Nothing is uploaded; the page makes no network request.
The riser trick
Reverse the crash, land it on the one.
The most reliable build in dance music is a sound played backwards, and getting it right is entirely about where it ends.
A cymbal forwards is an attack followed by a decay: it hits hard and fades away. Reversed, it becomes a swell that grows out of nothing and stops dead — which is exactly the shape of anticipation. The reason it works is that the ear reads a rising envelope as approach and a sudden stop as arrival, so a reversed crash tells a room something is coming and then delivers it, without a single note of melodic information.
The whole effect lives in the timing, and specifically in the end rather than the start. A reverse riser that ends a beat before the drop leaves a hole; one that ends a beat after steps on it. It has to stop precisely where the next thing begins. That means you build it backwards from the landing point: decide the bar the drop lands on, work back the length of the riser, and start it there.
Which is why this pairs with the fade tool and the beats-to-time calculator more than it looks like it should. Reverse the sound here, work out how many seconds a two-bar riser is at your tempo, trim or fade the front so it grows from silence rather than starting abruptly, and you have something that will drop into an arrangement on the grid. The reversal is the easy part.
A permutation, not a process
Reversing rearranges the samples and changes nothing else. Every value in the file is still there, in the opposite order, which means the peak level is identical, the loudness is close to identical, and there is no quality cost of any kind. That is worth stating plainly because a lot of tools offer to normalise the result afterwards, which is selling you a fix for a problem that cannot exist.
The click that appears out of nowhere
A DC offset is a constant displacement in the waveform — instead of sitting around zero it sits around, say, +0.02. Forward, this is inaudible: it is not a sound, it is a shift, and it just quietly eats a little of your headroom. Reversed, the file now begins at that displaced value rather than at silence, so the speaker cone has to jump there the instant playback starts. That is a click, on every play, and it is baffling if you do not know what causes it. The tool measures the offset and says whether you have one.
What it is actually for
Reverse cymbals and reverse risers into a drop, which is the oldest trick in dance music and still the most effective — a crash reversed and timed to end exactly on the one is an entire transition's worth of tension for no effort. Reversed vocal tails and reverb swells work the same way. Beyond effects it is a genuinely useful analysis trick: an intro that is hard to hear the start of is often obvious backwards, because the ear picks up an attack far better than a decay.
What changes
What reversing does and does not do
Short list, because the answer to most of it is "nothing".
| Property | After reversing | Why |
|---|---|---|
| Peak level | Identical. | The same samples in the opposite order. The loudest one is still the loudest one. |
| Loudness | Essentially identical. | Loudness is an average over the whole file, and the set of values has not changed. Only the gating can shift it by a fraction of a unit. |
| Frequency content | Identical. | Reversal does not shift or filter anything. A spectrum of the forward and reversed file is the same picture. |
| Envelopes | Inverted, and this is the whole point. | Attacks become decays and decays become attacks. A crash becomes a swell; a reverb tail becomes a reverse reverb leading into the sound. |
| DC offset | Same size, new place. | A constant displacement stays constant. But it now sits at the start of the file rather than the end, which turns it from inaudible into a click on playback. |
| File size | Depends on the output format. | A reversed MP3 written as a 24-bit WAV is much larger, because it is lossless. The audio has not changed. |
If the tool reports a DC offset above about 0.001, run the result through the silence trimmer afterwards or high-pass it in your DAW at 20 Hz. Both remove the click; the high-pass is the more correct fix because it removes the offset rather than hiding it.
Frequently asked
Common questions
Can I reverse a whole folder at once?+
Yes. Drop as many files as you like and they queue, each with its own DC-offset reading, and they come back as one archive rather than as a pile of separate downloads. The audio preview only appears on a single-file run — twenty stacked players is noise.
Does my file get uploaded?+
No. The audio is decoded, reversed and written back out inside your browser tab, and the page makes no network request once it has loaded.
Does reversing reduce audio quality?+
Not at all. It is a reordering of the existing samples, so nothing is filtered, resampled or recalculated. The only place any change enters is writing the result back to a fixed bit depth at the end, and choosing 24-bit or 32-bit float removes even that consideration.
Why do I hear a click at the start of my reversed file?+
Almost certainly a DC offset. If the original file sits slightly off zero — which happens with some synths, some cheap converters and a lot of old transfers — the reversed version begins at that offset value instead of at silence, so playback starts with an instantaneous jump. The tool measures the offset and tells you if you have one. A very short fade in, or a 20 Hz high-pass, fixes it.
Do I need to normalise after reversing?+
No, and any tool suggesting you do is not being straight with you. The peak level of a reversed file is exactly the peak level of the original, because it is the same sample. If you want the file at a different level that is a normalising job in its own right, and it has nothing to do with the reversal.
How do I make a reverse riser that lands properly?+
Work backwards from the landing point rather than forwards from the start. Decide the exact beat the drop happens on, work out how long your riser needs to be — two bars is the usual, four for something bigger — and place it so it ends there. The beats-to-time calculator converts bars to seconds at your tempo. Then a short fade in on the front of the reversed sound stops it starting abruptly, which is what makes it grow out of the mix rather than appear in it.
Can I reverse just part of a track?+
Not directly here — this reverses the whole file. To reverse a section, use the looper to extract the part you want, then reverse the result. Two steps, and both are lossless so nothing degrades in between.
What can I use a reversed track for legally?+
The same things you could use the original for. Reversing is a transformation you are performing on a file you already have, and it changes nothing about who owns the music. Sampling somebody else's record backwards is exactly as much a clearance question as sampling it forwards.
Why is the output WAV or AIFF rather than MP3?+
Because a reversed file is nearly always going somewhere else — into a DAW, into a sampler, into an edit — and putting a lossy encode in the middle of that chain throws away quality for no benefit. Both output formats are lossless and both import everywhere. Make an MP3 at the end if you need one.
How big a file can I reverse?+
Up to 800 MB, about 75 minutes of 24-bit stereo. Reversing a whole set is possible if slightly unusual.
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