Equalization (audio)

This article is about frequency-dependent processing of audio signals. For other uses, see Equalization (disambiguation).

A stereo graphic equalizer. For the left and right bands of the sound content, there are a series of vertical faders, which can be used to boost or cut specific frequency ranges. This equalizer is set to a smiley face curve, in which the mid-range sound frequencies are cut.
Equalizers are also made in compact pedal-style effect units for use by electric guitarists. This pedal is a parametric equalizer.

Equalization, or simply EQ, in sound recording and reproduction is the process of adjusting the volume of different frequency bands within an audio signal. The circuit or equipment used to achieve this is called an equalizer.[1][2]

Most hi-fi equipment uses relatively simple filters to make bass and treble adjustments. Graphic and parametric equalizers have much more flexibility in tailoring the frequency content of an audio signal. Broadcast and recording studios use sophisticated equalizers capable of much more detailed adjustments, such as eliminating unwanted sounds or making certain instruments or voices more prominent. Because of this ability, they can be aptly described as "frequency-specific volume knobs."[3]: 73 

Equalizers are used in recording and radio studios, production control rooms, and live sound reinforcement and in instrument amplifiers, such as guitar amplifiers, to correct or adjust the response of microphones, instrument pickups, loudspeakers, and hall acoustics.[2] Equalization may also be used to eliminate or reduce unwanted sounds (e.g., low-frequency hum coming from a guitar amplifier), make certain instruments or voices more (or less) prominent, enhance particular aspects of an instrument's tone, or combat feedback (howling) in a public address system.[1][2] Equalizers are also used in music production to adjust the timbre of individual instruments and voices by adjusting their frequency content and to fit individual instruments within the overall frequency spectrum of the mix.[3]: 73–74 

  1. ^ a b Strong, Jeff (2005). PC Recording Studios for Dummies. Wiley. p. 25. ISBN 9780764577079.
  2. ^ a b c Louie, Gary; White, Glenn (2005). The Audio Dictionary. University of Washington Press. p. 140. ISBN 9780295984988.
  3. ^ a b Hodgson, Jay (2010). Understanding Records. Bloomsbury Publishing USA. ISBN 978-1-4411-5607-5.