industrial rock artists generally employ the basic rock instrumentation of electric guitars, drums and bass and pair it with white noise blasts, electronic music gear (synthesizers, sequencers, samplers and drum machines). guitars are commonly heavily distorted or otherwise effected. bass guitars and drums may be played live, or be replaced by electronic musical instruments or computers. the early fusions of industrial music and rock were practiced by a handful of post-punk groups, including chrome, killing joke, swans, big black, and foetus. nine inch nails popularized industrial rock in the us with the release of "pretty hate machine" and "the downward spiral". industrial metal evolved from the scene, and is practiced by groups such as ministry, godflesh, and fear factory.