Disclosed are a determination method and apparatus for pre-set set parameters of an audio equalizer (AEQ), which are used for reducing an overflow phenomenon of fixed-point arithmetic output of all levels of second-order infinite impulse response (IIR) filters while frequency response amplitude curves of an AEQ remain unchanged, and reducing non-linear distortion, thus reducing total harmonic distortion (THD) of an AEQ system. The determination method for pre-set set parameters of an AEQ comprises: determining a first frequency point set by utilizing frequency response amplitude curves of an AEQ; adjusting the frequency response of frequency response amplitude curves of all levels of second-order IIR filters at a frequency point in the first frequency point set, so that the frequency response of the frequency response amplitude curves of all the levels of second-order IIR filters at the frequency point in the first frequency point set satisfies a pre-set condition; and adjusting a first parameter set and a second parameter set according to the adjusting variable of the frequency response amplitude curves of all the levels of second-order IIR filters, and determining the adjusted first parameter set and the adjusted second parameter set as pre-set set parameters of the AEQ.

An apparatus includes a plurality of delay elements, a plurality of multipliers and an accumulator to form a biquad stage; and a precision logic circuit. The biquad stage includes feedback paths; at least one feedback path has an adjustable bit precision; and the precision logic is adapted to regulate the bit precision of the feedback path(s) based at least in part on at least one parameter that is associated with the biquad stage.