OneTaskBy Tim King · Updated
Add Echo to Audio Online
Delay Effect for MP3 and Voice in Plain, Dark Tape or Ping-Pong Stereo
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How the Echo And Delay works
Use this to add echo to audio online with delay and feedback. Repeat a sound after a set gap, feed some of it back for a fading trail of echoes, and blend it with the original. Choose a plain digital repeat, a darkening tape-style echo or a ping-pong bounce between left and right. Preview and export in your browser; nothing is uploaded.
Add echo to audio online: what it does and why
Delay is the simplest time effect: the signal is stored for a set number of milliseconds and played again. Feed part of the output back into the input and the repeat repeats, each time quieter, producing the trailing echoes of a canyon or a dub mix. Three controls cover almost everything.
Delay time. The gap between the original and its first repeat. Under 30 ms the ear hears thickening rather than a separate echo; 80 to 150 ms is a slapback, the rockabilly and early-Elvis vocal sound; 250 to 500 ms is a distinct echo that suits speech and guitar; beyond that the repeats become rhythmic events of their own. To lock the echo to a song's tempo, divide 60,000 by the beats per minute for one beat in milliseconds, then halve or quarter it.
Feedback. How much of the echo is fed back to make the next one. Zero gives a single repeat. Forty percent gives four or five audible repeats fading away naturally. Above eighty the trail goes on for many seconds; the control stops at ninety-five to prevent an infinite, ever-louder loop. The stats panel estimates the number of audible repeats and the length of the tail, and the output file is extended to fit it.
Mix. The balance between dry and echoed signal. Twenty to thirty percent keeps the echoes behind the original so speech stays clear; fifty is equal and obviously effected; a hundred is echoes only, useful for layering later.
Styles. Plain repeats the signal exactly. Tape adds a low-pass filter in the feedback path so each repeat is darker than the last, the way tape echoes lost high frequencies with every pass — it sits behind a mix more gently than a clean digital repeat. Ping-pong sends the first echo to the left, the next to the right and so on, which is striking on headphones and turns a mono source into a wide stereo one.
Stereo output. The output is always stereo, even from a mono source, so ping-pong has somewhere to bounce. A stereo source keeps its image and the echoes follow it.
FAQ
How do I make the echo match the song's tempo?
Divide 60,000 by the tempo in beats per minute to get one beat in milliseconds — 120 bpm gives 500 ms. Use that for a quarter-note echo, half it for eighths, or multiply by 0.75 for a dotted eighth, the classic U2 rhythm.
Why does the file get longer?
The echoes continue after the last sound in the source. The page adds enough time for them to fade below audibility so the file does not end in an abrupt cut. If you want the original length, trim the result afterwards.
What is the difference between echo and reverb?
Echo is a small number of distinct, spaced repeats; reverb is thousands of reflections too dense to hear individually, blurring into a wash. Echo suggests a canyon or a tape machine; reverb suggests a room. Delay time above about 80 ms is heard as echo, below it as thickening.
Can I use it on a voice recording?
Yes. A short slapback of 100 ms with low feedback and a fifteen percent mix adds presence to a spoken voice without harming intelligibility. Longer echoes on speech quickly become confusing, so keep feedback and mix low unless the effect is the point.
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