The Limiter is a dynamics processing tool and used to reduce the dynamic range of audio. This essentially means reducing the difference in volume between the quietest and loudest audio signals. Limiters are commonly used in the final mastering process of a song but are also great tools to control dynamics on individual audio tracks.
Use to set the amount of audio signal volume sent into the threshold and limiting stage.
Set to determine where in the dynamic range limiting will be applied. Lower the threshold to apply more reduction of the dynamic range.
Release time controls for how long limiting is applied after a signal reaches the threshold. Another way to describe it is that it controls how fast the signal recovers after hitting the threshold.
The post gain knob scales the volume back up again after limiting has been applied.