Every car interior produces at least one sharp peak or dip in the frequency response that results in highly unnatural sound reduction. But the exact frequency and its level of intensity depends on unpredictable factors such as the size and volume of the interior, type of material used for the interior (i.e. cloth, leather, vinyl), whether a window is open, or how many passengers are onboard.

Because of these variables, even a multiband graphic equalizer will not be able to control a particular frequency without unnecessarily affecting others. The listener is therefore faced with either unwanted alterations of frequencies or having unnatural peaks and dips, which might result in boomy bass, muddied vocal ranges, or harsh treble responses.

The purpose of the 4 paragraphic frequency bands built into the CEQ-783 is to allow you to tune the basic frequencies in order to correct problems in car responses. Once brought into focus, the problem frequencies can then be attenuated or boosted. Precise control is therefore possible over the entire frequency range.