Patent ID: 8687822

Claim:
A filtering system for equalizing a loudspeaker system including a loudspeaker driven by an audio input signal comprising: an output for driving the loudspeaker, a single pole filtering section having at least two minimum phase single pole filters having corner frequencies for dividing the audio input signal into controllable frequency bands and having a gain stage for each frequency band, said gain stages having gain stage outputs which are summed to provide a single output for said single pole filtering section, wherein overall shaping of the frequency response of the audio input signal is achieved by setting the corner frequencies of the single pole filters and the gain of the gain stages of said single pole filtering section, and a parametric filtering section having at least one symmetric minimum phase second order parametric filter for providing correction for narrow band second order resonances, that exist in the environment of a particular application, said parametric filtering section being provided in conjunction with the overall shaping function of said single pole filtering section, wherein overall shaping of the frequency response of the audio input signal with correction for narrow band second order resonance is produced at the output of the filtering system with a composite complex frequency response having minimum phase.