Alternative pop/rock is a catch-all term for post-punk bands from the late 1980s to the early 1990s. Alternative rock encompasses a wide range of musical styles, from the sweet melodies of jangle-pop to the disturbing metallic grind of industrial, but they are all united by a common aesthetic: they all existed and operated outside of the mainstream. In some ways, alternative bands are divided into two waves, with Nirvana's unprecedented crossover success in 1991 serving as a dividing line. Throughout the 1980s, the majority of alternative bands were signed to independent labels; those who eventually signed to major labels, such as Hüsker Dü and the Replacements, didn't break through to the mainstream, allowing them to maintain their hip credentials. Alternative rock in the 1980s was even more diverse and fractured than mainstream rock; styles classified as alternative included roots rock, alternative dance, jangle-pop, post-hardcore punk, funk-metal, punk-pop, and experimental rock. After Nirvana's success in 1991, all of these genres entered the mainstream in some form or another, but their edges were sanded down because many of the new alternative bands were signed by major labels. As a result, '90s alternative rock often sounds more sanitised and homogeneous than its counterpart, especially since heavier material proved to have greater commercial appeal than alternative rock's quieter or quirkier elements. Most of these eccentric bands did not sign with major labels (those that did quickly vanished), preferring to stay on independent labels where they had more artistic freedom. The term "indie rock" was applied to these bands. Although the term had been around since the 1980s, it came to refer to bands that were dedicated to their own independent status, whether for musical or hipness reasons, in the 1990s.