Origins and early development
A number of heavy metal genres have developed since the emergence of heavy metal (often shortened to metal) during the late 1960s and early 1970s. At times, heavy metal genres may overlap or are difficult to distinguish, but they can be identified by a number of traits. They may differ in terms of instrumentation, tempo, song structure, vocal style, lyrics, guitar playing style, and drumming style, and so on.
Evolution or diversification
Alternative metal is a style of heavy metal and alternative rock which emerged in the mid-1980s and gained popularity in the early 1990s. Alternative metal usually combines heavy metal with influences from genres like alternative rock, and in some cases, other genres not normally associated with metal as well. One of the main characteristics of alternative metal and its subgenres are heavily downtuned, mid-paced "chug"-like guitar riffs. Alternative metal bands are also often characterized by melodic vocals, unconventional sounds within other heavy metal genres, unconventional song structures, and sometimes experimental approaches to heavy music.
Funk metal is essentially a fusion of heavy metal and funk. It started off in the late eighties as a subgenre of alternative metal and was heavily influenced by bands such as Red Hot Chili Peppers and Fishbone. The biggest regional scene during funk metal's prime was San Francisco.
Nu metal, also known as aggro metal, is a fusion genre that blends alternative metal and groove metal elements with other styles, including grunge, industrial, funk and hip hop.
Cultural or musical significance
Many of the early alternative metal bands originated from Los Angeles. Prominent bands in this genre include Soundgarden, Alice in Chains, Faith No More, Helmet, Life of Agony, Rollins Band and Tool. More modern bands include Breaking Benjamin, Chevelle, Godsmack and System of a Down.
