The architecture of three auditory filters: (a) a roex filter with parallel tip and tail filters (parameters: tl, tu, pl, pu, Gmax, and frat); (b) a compressive gammachirp filter with cascaded tail and tip filters (parameters: b1, c1, b2, c2, and frat); and (c) a compressive gammachirp filter with parallel tip and tail filters (parameters: b1, c1, b2, c2, Gmax, and frat). In each case, the level at the output of the tail filter determines the characteristics of the level-dependent tip filter.