An advantage of creating specific Audio Busses for different types of sounds, is that you can create dynamic relationships between those Busses. One of the most common examples of this is called Ducking. Ducking is a way to make the Volume of one Audio Signal path change depending on the Volume of another Audio Signal path. A classic example of this is with radio DJs. When they talk into their microphone, the presence of signal on the microphone is used to automatically turn down the music so the DJ’s voice can more easily be heard. When the DJ stops talking, the music is automatically turned back up.
Ducking is a powerful feature in Game Audio and this feature, available on Audio Busses, is very easy to set up. In this case, you’ll duck the Volume of the atmo when there’s explosions in the game, to make space and let the explosions hit even harder. You start by choosing the Bus whose Audio Volume you want to use to control another Bus.
Click the Destructable Bus in the Master-Mixer Hierarchy.
Now you need to designate which Bus you want to control with the Destructables Bus.
In the Auto-ducking Tab, click Insert.
Expand the Master Audio Bus, select Atmo, and click OK.
You now need to indicate how the Volume of the atmo Bus will be affected when there is an Audio Signal on the Destructables Bus. The default Volume change is -6dBFS, which is where Volume changes begin to become clearly noticeable. You’ll exaggerate the Volume change just a bit more. (Pic01 Auto-ducking)
Set the Volume Property to -9dBFS.
There are other Properties such as Fade In and Fade Out that determine how much time passes between when a signal is detected on the Bus, and the act of modifying the Target Bus occurs. The Target column currently indicates that the Volume change is happening to the Voice Volume. With Voice Volume selected, Volume is subtracted from the Voice Volume Property of each of the Objects that contribute to the atmo Bus. With Bus Volume selected, the overall level is being ducked. (Pic02 Ducking Volume)