Filter Design Using Second-Order Peaking and Shelving Sections
Jonathan S. Abel, David P. Berners · University of Michigan Library Repository · 2004
A method for designing audio filters is developed based on the observation that second-order peaking and shelving filters can be made nearly self-similar on a log magnitude scale with respect to peak and shelf gain changes.By cascading such second-order sections, filters are formed which may be fit to dB magnitude characteristics via linear least-squares techniques.A graphic equalizer interpolating prescribed band gains is presented, along with a filter minimizing the Barkweighted mean square dB difference between modeled and desired transfer function magnitudes.It is noted that using second-order sections parameterized by transition frequency and gain provides a natural mechanism for slewing and interpolation between tabulated designs.