OneTaskBy Tim King · Updated
Audio Looper
Seamless Loop Maker for Audio, Repeat a Clip With Crossfaded Joins
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How the Audio Looper works
This audio looper repeats any section of a track. Drop a file in, drag on the waveform to pick the section you want to loop, set how many times it should repeat and how long the crossfade at each join should be, then preview and export. The stats show the resulting length before you commit. The looping is done in this tab and the file is never uploaded.
Audio looper: what to know first
A loop is a short clip played end to end many times. It is the basis of most electronic music, of ambient beds for video, and of every hold-music track that ever existed. The hard part is not the repetition but the join: unless the clip ends at exactly the level and phase it starts at, each repeat clicks or thumps. The crossfade here solves that.
Choosing the section. Drag across the waveform to select the region to repeat, or leave it at the whole file. For a musical loop the section should be a whole number of bars, starting on a downbeat. The readout under the waveform gives the selection length to the hundredth of a second; at 120 beats per minute a bar is exactly two seconds, so check the maths against your tempo. The Audio Trimmer is the same waveform with finer readouts if you want to prepare the clip first.
How the crossfade works. Each repeat starts before the previous one has finished, by the crossfade length, and the two overlap with one fading out while the other fades in. A short crossfade of ten to thirty milliseconds removes clicks without being audible. A longer one, a few hundred milliseconds, smooths out loops of ambient sound like rain, engine noise or crowd murmur where there is no rhythm to preserve. Set it to zero for a hard butt join if your clip is already cut at zero crossings.
Length. Because the repeats overlap, the total length is the clip length times the repeat count minus one crossfade per join. The stats panel works this out for you. Five hundred repeats of a one-bar loop is a long file — the memory guidance of roughly an hour of stereo still applies to the output.
Uses. Extend a short sample of room tone to cover a whole scene; turn a two-bar drum break into a four-minute backing track; make a test tone that runs for an hour; build background ambience for a game. Anything the browser can decode can be looped, and the result exports as WAV or MP3.
FAQ
How do I make the loop seamless?
Select a region that starts and ends at similar points in the sound, then use a crossfade of twenty milliseconds or more. For rhythmic material, keep the crossfade short and get the bar length right; for textures, use a long crossfade and the exact length matters less.
Why does the total length not equal the clip length times repeats?
Because each join overlaps by the crossfade length. Four repeats with three joins and a 100 ms crossfade is 300 ms shorter than four clips end to end. Set the crossfade to zero for exact multiples.
Can I loop only part of the file and keep the rest?
This tool exports the looped section on its own. To place the loop back into a longer file, export it, then join it with the other sections using the Audio Joiner.
Is there a maximum number of repeats?
Five hundred. The practical limit is memory: the output is held uncompressed at about ten megabytes per stereo minute, so keep the total length under an hour or so.
See also: all Audio tools, Images, Video & Screen, PDF, SVG, Simulations & Screensavers, Generative Art, Chart Makers, 3D Model Viewers, Drawing Pads, Mockups & 3D Making, Diagram Makers, 3D Science, Tracker Music.
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