Reverse Audio Online: Play Sound Backwards
Play audio backwards in your browser. Exact sample-order reversal with anti-click edge smoothing, per channel or whole file.
Reversing audio is a pure reordering: sample N swaps with sample N-from-the-end and nothing else about the signal changes, no filter, no resampler, the sample values themselves are untouched, only their order changes. Reverse the result again and you get the original back exactly. The practical wrinkle is the edges: most recordings end on a decaying tail, so the reversed file starts at the loudest point of that tail, and an abrupt first sample clicks on playback. The edge-smoothing toggle applies a 10 ms micro-fade to each end of every reversed channel: too short to hear as a fade, long enough to remove the click. Turn it off when you need the mathematically exact reversal, for example to reverse a file, process it elsewhere, and reverse it back. The channel modes reverse just the left or right side while the other plays forward, the classic trick for backwards-reverb swells on one side of the stereo field.
How to Use It
- Upload your audio file and wait for the local preview to load.
- Adjust the settings: Choose which channels to reverse and leave the 10 ms edge smoothing on unless you need a sample-exact reversal.
- Download the result: Download the processed file directly to your device.
Controls and Options
Keep Both channels for the full backwards effect. Switch to Left only or Right only to put a reversed texture on one side of the stereo field, and turn off edge smoothing only when you plan to reverse the file back to the original.
Formats and Output
Input: MP3, WAV, M4A, AAC, OGG, FLAC. Whatever audio your browser can decode. Output: 16-bit WAV, so the reversed audio is not re-compressed.
Frequently Asked Questions
Does reversing change the sound quality?
No. Reversal is a pure reordering of samples. The backwards file contains the same sample values as the source, just in the opposite order, so there is no filtering, no resampling, and no generation loss in the samples themselves. The export is 16-bit WAV, so nothing is re-compressed either.
If I reverse a reversed file, do I get my original back?
Yes, exactly. Reversal is its own inverse. With edge smoothing turned off, reversing twice reproduces the original signal sample-for-sample. With smoothing on, the 10 ms faded edges are the only difference.
Why does the reversed file start with a loud swell?
Because most recordings end on a decaying tail. A ring-out, a reverb, a crash cymbal. Reversed, that decay becomes a crescendo at the very start of the file. That swell is the sound people usually want from this effect; the edge smoothing only removes the single-sample click at the boundary, not the swell.
What are the left-only and right-only modes for?
Creative stereo effects. Reversing one channel while the other plays forward puts a backwards texture on one side of the stereo field against the normal performance on the other. On a mono file there is only one channel, so any mode reverses it; the result panel reports which channels were actually reversed.
Which formats can I reverse, and why is the output WAV?
Input is whatever your browser can decode. Commonly MP3, WAV, M4A/AAC, OGG, and FLAC. Output is 16-bit WAV because encoding to MP3 again would add a second generation of lossy compression to audio that the reversal itself left untouched.
Is my audio uploaded anywhere?
Supported audio content is not uploaded for processing. Reading, reversing, and export run in your browser; site analytics and the assistant are separate.