==== Rhythm and tempo ====

The rhythm in metal songs is emphatic, with deliberate stresses. Weinstein observes that the wide array of sonic effects available to metal drummers enables the "rhythmic pattern to take on a complexity within its elemental drive and insistency."In many heavy metal songs, the main groove is characterized by short, two-note or three-note rhythmic figures—generally made up of [8th] or [16th] notes. These rhythmic figures are usually performed with a staccato attack created by using a palm-muted technique on the rhythm guitar."Master of Rhythm: The Importance of Tone and Right-hand Technique," ''Guitar Legends'', April 1997, p. 99

Brief, abrupt, and detached rhythmic cells are joined into rhythmic phrases with a distinctive, often jerky texture. These phrases are used to create rhythmic accompaniment and melodic figures called [[riff]]s, which help to establish thematic [[Hook (music)|hooks]]. Heavy metal songs also use longer rhythmic figures such as [[whole note]]- or dotted quarter note-length chords in slow-tempo [[power ballad]]s. The tempos in early heavy metal music tended to be "slow, even ponderous." By the late 1970s, however, metal bands were employing a wide variety of tempos. In the 2000s, metal tempos range from slow ballad tempos (quarter note = 60 [[beats per minute]]) to extremely fast [[blast beat]] tempos (quarter note = 350 beats per minute).



Underground metal: 1980s, 1990s, and 2000s

Many subgenres of heavy metal developed outside of the commercial mainstream during the 1980s. Several attempts have been made to map the complex world of underground metal, most notably by the editors of Allmusic, as well as critic Garry Sharpe-Young. Sharpe-Young's multivolume metal encyclopedia separates the underground into five major categories: thrash metal, death metal, black metal, power metal, and the related subgenres of doom and gothic metal.