Filters are used to emphasize or suppress frequencies in an audio signal, resulting in a change in the tonal color of the audio.
MainStage 3 contains a variety of advanced filter-based effects that you can use to creatively modify your audio. These effects are most often used to radically alter the frequency spectrum of a sound or mix.
Note: Equalizers (EQs) are special types of filters. They are not usually used as “effects” per se, but as tools to refine the frequency spectrum of a sound or mix. See Equalizers overview.