Why is the output file longer than the input?

The tail seconds extend the render so the last few delay repeats can ring out. Reduce the tail if you want a hard cut.

What feedback value causes runaway?

Above 90 percent the echoes grow instead of fade. The tool caps feedback at 95 percent to avoid infinite self-oscillation.

Not in this release — the current implementation uses a single mono delay line applied to each channel. Ping-pong is on the roadmap.

Add a classic delay or slapback echo to your audio. Control the delay time, feedback, and mix.

Drop an MP3 or WAV file here

or click to browse

Your audio never leaves your browser. The effect renders locally via the Web Audio API.