Wah

A foot-operated filter pedal that sweeps a resonant peak up and down the frequency spectrum, producing the vocal, crying sound basic to funk and rock.

It is a bandpass filter with a strong resonance at the cutoff, moved by a treadle rather than by the playing, and the position of the pedal is the parameter: heel down gives a dark, muffled tone and toe down a bright, nasal one. Because it works on the signal before distortion in most setups, where it sits in the chain changes its character considerably, particularly with fuzz. Some wahs are auto-triggered by playing dynamics instead.

Example: a wah parked in one position and held there through a riff gives a fixed, vocal midrange colour rather than a sweep.

Wah

See also