ABSTRACT
In a sense, any audio effect could be considered a filter in that every effect performs mathematical operations on the input signal that produce some change in the content. This chapter, however, is concerned with effects based on the canonical types of filters defined in Chapter 3: low-pass, high-pass, band-pass, peaking/ notch, shelving, and allpass filters. The effects that fall into this category are equalizers, a broad class of effects that adjust the frequency balance of the input audio signal; wah-wah, a musical effect typically used on guitar that is based on a peaking filter; and the phaser, an effect based on allpass filters that produces a sweeping, spacious sound similar to the flanger (Chapter 2).
