
Legacy Ducker in MainStage
Ducking is a common technique used in radio and television broadcasting. When the DJ or announcer speaks while music is playing, the music level is automatically reduced. When the announcement has finished, the music is automatically raised to its original volume level. Ducker provides a simple means of achieving this result with existing recordings. It does not work in real time.
If you’re new to using plug-ins in MainStage, see Add and remove plug-ins in MainStage.
Note: For technical reasons, Ducker can be inserted only in output and aux channel strips.

Ducker parameters
Ducking checkbox: Turn ducking on or off.
Amount slider and field: Set the amount of volume reduction of the music mix channel strip—in effect, the output signal.
Threshold slider and field: Set the lowest level that a side chain signal must reach before the music mix output level is reduced (by the value set with the Amount slider). If the side chain signal level doesn’t reach the threshold, the music mix channel strip volume is not affected.
Attack slider and field: Control how quickly the volume is reduced. If you want the music mix signal to be gently faded out, set this slider to a high value. The Attack value also controls whether or not the signal level is reduced before the threshold is reached. The earlier this occurs, the more latency is introduced.
Note: Ducker does not work with live (real-time) ducking signals. The ducking signal must be an existing recording. MainStage needs to analyze the signal level before it is played back to predefine the point where ducking begins.
Hold slider and field: Define the length of time that the music mix channel strip volume is reduced. This control prevents a chattering effect that can be caused by a rapidly changing side chain level. If the side chain level hovers around the threshold value rather than clearly exceeding or falling short of it, set the Hold parameter to a high value to compensate for any rapid volume reductions.
Release slider and field: Control how quickly the volume returns to the original level. Set it to a high value if you want the music mix to slowly fade up after the announcement.
Lookahead checkbox: Turn on to make sure that Ducker reads the incoming signal before processing. This results in no latency—it is primarily intended for slower computers.
Use the Ducker plug-in
In MainStage, insert Ducker into an aux channel strip.
Assign all channel strip outputs that are supposed to “duck” (dynamically lower the volume of the mix) to a bus—the aux channel strip chosen in step 1.
In the Ducker plug-in window header, choose the bus that carries the ducking (vocal) signal from the Side Chain pop-up menu.
Note: Unlike all other side chain-capable plug-ins, the Ducker side chain is mixed with the output signal after passing through the plug-in. This ensures that the ducking side chain signal—the voiceover—is heard at the output.
Adjust the Ducker parameters.