A ducking delay is one that changes the volume of the actual repeats in response to your playing: While you are playing, the echoes are quieter, and when you stop, they get louder. ... This dynamic use of delay allowed control over the volume of the echoes that didn't exist outside of a recording studio.

What is a ducked delay?

A ducking delay is a technique that is a very widely used in almost all areas of music and audio production. Essentially, it is a delay effect that uses the power of side-chaining to create interesting effects such as applying the delay only when there is no audio signal present on the track.

What is ducking in recording?

Ducking temporarily lowers, or “ducks,” the volume level of a specified audio signal anytime a second specified audio signal is present. In live sound, ducking is commonly used to lower background music anytime a person speaks, then raises it when that person finishes speaking, as in the emcee example above.