Quad Lim is the limiter version of Quad Comp, which, according to the limiting principle, has a fixed, infinity-to-1 ratio. Time constants and makeup gain are user definable for increased control. As with Quad Comp you can adjust the slope of the filters that split the frequency bands, so that dynamics control is broader or sharper, depending on your needs.
As for the Quad Comp the quality and transparency of the filters used for the band splitting was particularly important so that no artifacts or ringing are generated at the crossover points.
As an additional layer of control, Quad Lim features a master brickwall limiter post multi-band processing that can be engaged to avoid overshoots. Being of the brickwall type this limiter makes sure the program cannot go past the 0 dBFS level no matter how the gain of the previous bands is set. By judiciously setting the gain structure of the band-limiters and master brickwall maximum loudness without distortion can be achieved.
This processor is incredibly handy as a finishing mastering tool on the stereo bus of your mix; by applying limiter only on selected parts of the audio spectrum and only when the level of that band overcomes the set threshold a double effect is achieved: frequency conscious dynamic control. This will allow the perfect EQ balance of a mix that wasn't properly right, particularly in situations where the program material can drastically change over time, like live recordings.