Difference between revisions 601667459 and 640298596 on enwiki

{{merge from|Equalizer (communications)|discuss=Talk:Equalization#Equalization_organization|date=January 2013}}⏎
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{{about|electronic compensation for systems' uneven frequency responses|equalization particularly as used in sound recording and reproduction|Equalization (audio)}}
{{other uses|Equalization (disambiguation)}}⏎
{{merge from|Equalizer (communications)|discuss=Talk:Equalization#Equalization_organization|date=January 2013}}

'''Equalization''' (British: '''equalisation''') is the process of adjusting the balance between [[frequency]] components within an electronic [[Signal (electronics)|signal]]. The most well known use of equalization is in [[sound recording and reproduction]] but there are many other applications in electronics and telecommunications. The circuit or equipment used to achieve equalization is called an equalizer.  These devices strengthen (''boost'') or weaken (''cut'') the energy of specific frequency [[Frequency range|bands]].  

In telecommunications, equalizers are used to render the [[frequency response]]—for instance of a telephone line—''flat'' from end-to-end. When a [[communication channel|channel]] has been "equalized" the [[frequency domain]] attributes of the signal at the input are faithfully reproduced at the output. Telephones, [[DSL]] lines and television cables use equalizers to prepare data signals for transmission.

(contracted; show full)n of the center frequency (in [[Hertz|Hz]]), adjustment of the [[Q factor|Q]] which determines the sharpness of the [[Bandwidth (signal processing)|bandwidth]], and the level or gain control which determines how much those frequencies are boosted or cut relative to frequencies much above or below the center frequency selected. In a ''semi-parametric'' equalizer there is no control for the bandwidth (it is preset by the designer) or is only selected between two presets using a switch.{{c
nitation needed|date=January 2013}} In a ''quasi-parametric'' equalizer, the bandwidth is depending on the gain level. With rising gain, the bandwidth gets wider.{{cnitation needed|date=January 2013}}

A [[graphic equalizer]] also implements second-order filter functions in a more user-friendly manner, but with somewhat less flexibility. This equipment is based on a bank of [[Filter bank|filters]] covering the audio spectrum in up to 30 frequency bands. Each second-order filter has a fixed center frequency and [[Q factor|Q]], but an adjustable level. The user can raise or lower each slider in order to visually approximate a "graph" of the intended frequency response.

(contracted; show full)*[[Electronic filter]]
*[[Adaptive equalizer]]
*[[Loudness compensation]]
*[[Weighting filter]]

==References==
{{Reflist}}

<div class="references-small">{{refbegin}}
:*Glen Ballou, "Filters and equalizers", ''Handbook for Sound Engineers'', Fourth edition, Focal Press, 2008 ISBN 0-240-80969-6.
</div>{{refend}}

==External links==
{{Wiktionary|equalisation|equalization}}
*[http://www.audiocheck.net/engineertraining_bands_difficult.php Discriminating EQ frequencies by ear]
*[http://www.sengpielaudio.com/calculator-bandwidth.htm Calculator: bandwidth per octave ''<math>N</math>'' to quality factor ''<math>Q</math>'' and back]
*[http://www.idc.ul.ie/idcwiki/index.php/Equalisation EQ Condensed Overview]
*[http://www.wikirecording.org/EQ WikiRecording's Guide to Equalization]
*[http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt Audio EQ Cookbook]

{{Music technology}}

[[Category:Audio effects]]
[[Category:Linear filters]]
[[Category:Tone, EQ and filter]]