Graphic Equalizers
A graphic equalizer is, as the name implies, an equalizer which uses a graphical layout to represent the changes made. It uses a series of sliders (usually vertical) which correspond to a set of fixed frequency bands. You raise or lower each slider to boost or lower (attenuate) the level of that frequency band.
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Graphic equalizers are commonly referred to by the number of bands (e.g. 51-band, 31-band) or by the frequency separation of each band expressed in octaves (e.g. 2/3 octave, 1/3 octave, 1/6 octave).