Operator Adjustable Full-bandwidth Audio Spectral Shifting Control with a Simple Listener Interface

A spectral response shifting method allows a listener to shift a system response to match their preferences. The method includes a lookup table of coefficients for a number of Infinite Impulse Response (IIR) filter or Finite Impulse Response (FIR) filter which are selected by the listener to shift the response either toward bass or towards treble. In one embodiment, 5th order IIR biquads filters are used at ½ dB increments from -6 dB to +6 dB. For example, when a listener selects the "more treble by 1 dB" setting, a set of coefficients is loaded providing -1 dB in bass cut at the lowest frequency of the audible spectrum (20 Hz) and +1 dB of treble boost at the highest frequency of the audible spectrum (20 kHz). The frequency response at all other points is defined by interpolating between the highest frequency (20 kHz) and the lowest frequency (20 Hz).