Add a single slapback echo or repeating delay. Adjust delay time, feedback, wet mix and output trim live, then preview a WAV with an automatic, custom or trimmed tail.
Your content stays on your device Free, with no account
Give sound a second life. Shape the repeats. Local audio · no uploads
No file selected.
Up to 128 MiB per file; decoded audio up to 256 MiB (about 23 min mono / 11½ min stereo). Formats depend on your browser's decoder. Working audio and WAV exports use 48 kHz.
Choose audio to begin. Nothing plays automatically.
Source waveform
No audio loaded
Your waveform will appear here.
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Load audio to choose a section.
Click the waveform to seek the source; use Play/Pause, exact time or jump controls. Delay, feedback, mix and trim change live. This source audition stops at the source end; create the WAV to hear its complete selected tail. Seeking or resuming resets echo history.
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Playback stopped.
Echo & delay settings
Change settings while playing to hear echo live. Uncheck to compare original audio; exports always use the selected effect.
Time before the first echo. Working delay is rounded to the nearest sample. Changing delay during playback can briefly bend pitch while it settles.
How much of each echo feeds the next. 0% gives one repeat; higher feedback produces more repeats. Limited to 85% for stability.
0% is original audio before output trim; 100% is echo only. Dry/wet is a linear crossfade. Echo-only audio starts after the delay.
Applies to both dry and echo output. Repeats can build up and clip: lower trim as needed. No automatic limiter or normalization.
Auto includes the first repeat below −60 dB relative to the first echo, capped at 20 seconds. It is a repeat-decay estimate, not a measured silence threshold.
The output ends exactly at this limit; remaining echoes are cut without an automatic fade. Zero wet mix disables appended tails.
Quick sliders pause for exact values finer than their steps; your entered value stays usable. Presets also set output trim and tail mode.
Planned output durationChoose audioDelay and tail details appear here.
The original file stays unchanged.
Listening volume affects monitoring only. Source and result use the same duration; listening volume does not affect export.
Input up to 128 MiB; source and output float audio each have a 256 MiB limit. Appended tails may exceed the output budget for a large source. Live source audition has no appended tail; the actual WAV player includes it.
ACTUAL ECHO WAV
Hear and download the result
Create a WAV to preview the actual adjusted file.
48 kHz · 16-bit PCM WAV · original channel count. Independent stereo delay lines use shared settings; no ping-pong routing or automatic tempo sync. Feedback is retained internally without hard clipping; final PCM clipping is counted. No automatic normalization or limiter. Tags/artwork are omitted. Tail limits cut off remaining echo without a fade. Settings changes clear exports; Stop terminates the local worker.
A FEW SIMPLE STEPS
How to use Echo / Delay
Choose or drop audio, or try the sample. Wait for filename, size and ready status.
Choose a preset or set delay, feedback, wet mix and output trim. Choose automatic tail, a custom tail up to 20 seconds, or trimming at the source end.
Press Play preview and adjust controls live over the source section. Seek with the waveform or transport controls; bypass to compare original audio.
Create the echoed WAV, hear the complete actual output including the selected tail, then download it. Changes invalidate old exports.
PRIVATE BY DESIGN
Why use this tool?
Your audio is never uploaded to any server. Decoding, echo processing, playback and WAV encoding run entirely in your browser using self-hosted code. The original file stays unchanged, with no account or audio history.
Tool inputs stay in your browser. Only your theme preference is saved on this device.
A few things worth knowing
How do delay, feedback and wet mix work?
Delay sets the time before the first echo, rounded to the nearest 48 kHz sample. Feedback feeds each echo into the next: 0% gives one repeat; higher values create more repeats. Wet mix is a linear crossfade: 0% is original audio before trim and 100% is echo only, starting after the delay. Stereo channels use independent delay lines with the same settings; no ping-pong routing is added.
Which tail options are available?
Auto estimates repeats until the first one below −60 dB relative to the first echo, capped at 20 extra seconds. It is not a measured silence detector; cap/trim/manual limits can cut audible repeats without a fade. Manual adds 0–20 seconds, or Trim keeps original duration. Zero wet mix disables appended tails. Output duration and tail length are displayed before export.
Can I hear the tail during live preview?
The live source audition stops at the end of the source section. Create the WAV and use its actual output player to hear the complete chosen tail. Delay, feedback, mix and trim update live within the source audition without restarting. Live changes are smoothed; changing delay can briefly bend pitch. Export applies current fixed settings, not a history of live knob movements.
What happens when I seek or resume?
The source player starts a fresh delay line at the chosen position, so previous echo history is not reconstructed. That can sound different from the full-file export around the seek/start boundary. The actual generated WAV contains the complete processed history and has its own seeking controls.
Why can echo-only audio be silent?
With 100% wet mix, sound appears only after the delay. If the delay is longer than the clip and the tail is trimmed, there may be no echo within the output. Keep a tail or reduce wet mix/delay. No automatic loudness compensation or normalization is added; output trim affects dry and wet sound, while listening volume affects monitoring only.
Can repeats cause clipping?
Yes. Feedback is bounded to 0–85% for stability, but echoes can add up beyond the PCM range. Feedback remains unclipped internally; final out-of-range output samples are hard clipped and counted. Reduce output trim, feedback or wet mix. There is no automatic limiter. Stop, edit, clear or replacement terminates the local export worker and invalidates old results.
What are the limits?
Delay 20–2,000 ms, feedback 0–85%, wet mix 0–100%, trim −24 to +6 dB and tail up to 20 seconds. One mono/stereo source up to 128 MiB, decoded at 48 kHz within a 256 MiB float budget. Output has its own 256 MiB float budget, including tail; large sources may need a shorter/trimmed tail. Device memory can impose lower limits. Live AudioWorklet needs HTTPS or localhost and a supported browser. Export is 48 kHz 16-bit PCM WAV; tags/artwork are omitted.
