A shelving filter that exhibits an adjustable transition band is derived from a cascade of second order infinite impulse response shelving filters. Two of three parameters, i.e. shelving level, transition slope and transition bandwidth, can be freely adjusted in order to describe the design specifications. The accuracy of the resulting response depends on the deployed number of biquads per octave. If this is set too small, deviations in level and bandwidth as well as a rippled slope can occur. The shelving filter cascade might be used in applications, that require a fractional-order slope in a certain bandwidth, such as for sound reinforcement system equalization, sound field synthesis and audio production.
Authors: Frank Schultz (Institute of Communications Engineering, University of Rostock, Germany), Nara Hahn (Institute of Communications Engineering, University of Rostock, Germany) and Sascha Spors (Institute of Communications Engineering, University of Rostock, Germany)