The Ducker module is a dynamic processor that lowers (or ducks) the level of one audio signal based upon the level of a second audio signal. A typical application is paging over background music: A ducker senses the presence of audio from a paging microphone and triggers a reduction in the output level of the music signal for the duration of the page signal. It restores the original level once the page message is over. Definition Source
In the DSP schematic, drag and drop a Ducker DSP module. You will notice a Priority Input on the module. The Priority Input acts as a trigger. The signal feeding into the Priority Input will adjust how much the Ducker module will affect the level.
Threshold: The minimum level in decibels (dB) at which the module is triggered.
Depth: The number of decibels (dB) the audio level will be lowered.
Attack: The time it takes for the module to respond once threshold level is reached.
Hold time: The time the module holds before releasing the effect.
Release: The time it takes for the audio level to go back to the original, unaffected volume.
Attenuation: The amount of reduction that is applied to the source.