Abstract: A parametric audio equalizer has linear frequency response controls for bass, middle and treble frequency ranges arranged in a line according to the frequency ranges, and linear amplitude controls arranged perpendicularly to the corresponding frequency response selection controls, with a bandwidth selector for the middle range located below the middle range amplitude control. Simple graphic indicia of frequency responses appear near the corresponding controls. A summing circuit combines the input signal with signals on + and - inputs coupled to a variable Q and frequency bandpass filter.