Drone metal or drone doom is a style of heavy metal that melds the slow tempos and heaviness of doom metal with the long-duration tones of drone music. Drone metal is sometimes associated with post-metal or experimental metal. Characteristics Typically, the electric guitar is performed with a large amount of reverb or audio feedback while vocals may or may not be present. Songs often lack beat or rhythm in the traditional sense and are typically very long. The experience of a drone metal performance has been compared by novelist John Wray in The New York Times to listening to an Indian raga in the middle of an earthquake. Wray also states, "It's hard to imagine any music being heavier or, for that matter, very much slower." A pioneer band of drone metal called Sunn O))) has indicated a kinship with sound sculpture. Jan Tumlir indicates a "sustained infra-sound rumble of sub-bass—so-called brown noise". History Precursors Early guitar-produced drone effects go as far back as the krautrock (for example Cluster II by Cluster, 1972) and early noise rock / industrial music era (Metal Machine Music by Lou Reed, 1975; Stahlwerksynfonie by Die Krupps, 1981). 1990s Drone metal was first established by Earth, a group from Olympia, Washington, formed in 1989, which has been described as "minimalist post-grunge". Earth took inspiration from the sludge metal of Melvins and the minimalist music of La Monte Young, among other sources. Stephen O'Malley's group Burning Witch, formed five years later, also in Seattle, continued in this tradition, incorporating unusual vocals and bursts of audio feedback. The group initially recorded for the prominent powerviolence label Slap-a-Ham. O'Malley's subsequent group, Sunn O))), initially formed as a tribute to Earth, is most responsible for the contemporary prominence of the drone metal style. Godflesh is also a stated influence on many groups. Boris, from Tokyo, also developed a style of drone metal, parallel with the Seattle groups, as did Corrupted, from Osaka. 2000s Nadja (Toronto), Locrian (US), Jesu (UK), Black Boned Angel (Wellington, New Zealand), Khanate (New York City), Ocean (Portland, Maine), Growing (New York City), KTL (Washington/London), Ascend and Eagle Twin (USA), Teeth of Lions Rule the Divine (Nottingham, England), Conan (Liverpool, England) and Moss (Southampton, England) are prominent drone metal groups that formed in the early 21st century. Noise musicians, such as Kevin Drumm and Oren Ambarchi, have also worked in the style. Rhys Chatham's Essentialist project