The term equaliser - we’ll use the abbreviated form ‘EQ’ from hereon - originates in telephony where it was used to compensate for the tonal side effects of early phone systems. On a modern day mixer, EQ is designed to alter the tonal quality of any audio passing through, whether it is a traditional analogue console or a computer-based mixing system. EQ alters the sound, either by applying gain (or ‘boost’) to the signal over the selected frequency range, or by applying ‘cut’ and instead reducing the level of frequencies within the specified band. The amount of boost or cut is usually scaled in decibels (dB).
