Sidechain processing uses the level of one audio signal (the "key" or "trigger") to control a dynamics processor on a different signal. The most common use is sidechain compression, where a kick drum triggers compression on a bass or pad, creating the classic "pumping" effect.
Common uses in game audio:
- Ducking — automatically lowering music when dialogue plays
- Sound design — using one sound's envelope to shape another
- Mix clarity — ensuring important sounds cut through
Most DAWs and middleware engines support sidechain routing. In Wwise, this is achieved through ducking profiles and bus-level sidechaining.