GALLERY: South by Southwest 2011

Sometimes simply referred to as “the ’90s wah,” the Dunlop Cry Baby BB535 first emerged in 1994 in the wake of the early-’90s grunge and alternative rock movement, which revitalized interest in an effect that felt somewhat dated by the previous decade.

But beginning with Slash's 1987 “Sweet Child o’ Mine” solo, and Mike McCready’s 1991 solos on Pearl Jam’s “Alive” and “Black,” the wah’s classic timbre blasted triumphantly on rock radio. Meanwhile, a new generation of heavy ax iconoclasts—Tool’s Adam Jones, Soundgarden’s Kim Thayil, Alice in Chains’ Jerry Cantrell, and Pantera’s Dimebag Darrell among them—were exploiting the wah for even darker, more menacing textures on drop-D riffs and raucous lead lines.