EQualizer The part of an audio mixer or separate audio system component that adjust the tonal quality of an audio signal by breaking it up into individual frequencies / filters, or groups of frequencies. The user can cut or boost the level of these frequencies or groups, thus changing the tone of the original sound. There are two major sub-categories: Graphic: Also known as "1/3-octave" or "31-band". The K/T DN360 is a standard. Parametric: Usually 4-band, four selectable frequency ranges of adjustable width, "Q". Often also includes hi-cut and low-pass (hi-pass and low-cut) filters.