Noise-Rock is an outgrowth of punk rock, specifically the sort of punk that expressed youthful angst and exuberance through the glorious racket of amateurishly played electric guitars. Noise-rock, like its forerunner no wave, aims to be more abrasive, sometimes for comic effect and sometimes to make a statement, but always concentrating on the sheer power of the sound. While most noise-rock bands concentrate on the ear-shattering sounds that can be produced by distorted electric guitars, some also use electronic instrumentation, whether as percussion or to add to the overall cacophony. Some groups are more concerned than others about integrating their sonic explorations into song structures; pioneers Sonic Youth helped bring noise-rock to a wider alternative-rock audience when they began to incorporate melody into their droning sheets of sound. Sonic Youth produced a bevy of imitators, but not all noise-rock resembles their music -- '80s bands like the Swans and Big Black took a much darker, more threatening approach, and the Touch & Go label became a center for crazed, shock-oriented takes on the style in the late '80s and '90s. A certain theatrical sub-style of noise-rock, often described as "scuzz-rock" or with similar terms, uses the guitar noise to help create a dirty, decadent, repulsive atmosphere (bands like this include Royal Trux, Pussy Galore, the Dwarves, and the Butthole Surfers).