The general characteristics of heavy metal is loud distorted guitars, dense bass, thumping drums and fast vocals. Unlike other hard rock, it focuses less on syncopation and more on powerful force.
One of the main components of heavy metal music is the concept of the guitar. A number of bands feature multiple musicians playing the instrument. In addition, guitars generally play a similar role to that of the lead singer.
A number of subgenres exist within the confines of heavy metal music. The most notable of these categories are thrash metal, death metal, power metal, black metal, doom metal and gothic metal. A metal-rap fusion style known as "nu metal" developed during the 1990s.
Much of the style of the genre came from heavily distorted music of the 1960s. Acid rock band of the 1970s perfected the style and it became popularized in the 1980s with a number of MTV bands and a growing underground market.
Early bands of the genre include Led Zeppelin and Black Sabbath. Bands that helped popularize heavy metal include Motley Crue, Ratt and Quiet Riot. Some of the most successful include Poison, Guns N' Roses, Def Leppard, Metallica and Slayer.