Filter morphing for audio signal processing

The coefficient encoding scheme called “ARMAdillo” for a second order direct form digital filter was previously proposed. We examine the behavior of a second order digital filter, whose coefficients are encoded using the ARMAdillo scheme, when it morphs from one frame to another. We restrict our discussion to biquadratic parametric equalizers and shelving filters. Results show that using encoded coefficients, the morphing performance of a parametric equalizer or shelving filter is far superior to the non-encoded case