Type of equalizer that allows the user to adjust a signal’s frequency response with complete choice over how to break up the signal and adjust it using amplitude, center frequency and bandwidth. qualizers adjust frequency response by changing the amplitude of a signal at a certain point thus changing the loudness of the signal at that point. This can be used to boost a signal that sags or loses output over a certain frequency band or bring down a signal that is too powerful over a certain frequency band with the end result being a flat (or flatter) frequency response (a flat frequency response being a desirable trait meaning the audio system is not attenuating or boosting the signal where it should not). When a signal is equalized, its amplitude is changed at some center frequency and over some range or band of frequencies on either side of the center. n a graphic equalizer the center frequencies and associated bands are fixed with only the amplitude adjustable. A parametric equalizer allows the user to select the center frequency and bandwidth to be affected by an amplitude adjustment. In this way, the parametric equalizer offers the maximum amount of flexibility and customizability versus a graphic equalizer. Generally, a graphic equalizer is adjustable at a large number of frequencies (as many as 30 center frequencies) to allow fairly precise control over the frequency response while a parametric equalizer only adjusts a few areas of the frequency, which are carefully chosen.