Metal/Heavy Metal grew quite naturally from the origin of rock music in the late sixties. Following the Hendrix era, bands such as Led Zeppelin, Black Sabbath and Alice Cooper were experimenting with heavily distorted guitar sounds and darker themes.
UK acts such as Iron Maiden and Motorhead added more of a punk ethos and during the 1980s, thrash metal was born. Artists such as Metallica, Slayer, Megadeth and Anthrax became titans of the genre. Since then, metal has expanded into further fields such as nu metal, death metal and black metal, with many fusion genres existing today.
In terms of musicality, metal is usually high tempo and in a minor key, featuring large drum fills, aggressive vocals and the occasional guitar solo. An iconic ‘riff’ in each song is paramount in metal, from iconic guitar lines in Metallica to huge breakdowns and dischords in modern hardcore. Scales used are primarily the pentatonic, natural and harmonic minor scales and are played with impressive accuracy up and down the fretboard.
Another common technique in modern metal guitar is tuning the guitar down two steps and then dropping the top string so the guitar tuning is CGCFAD (Drop C). Despite saying this, standard tuning and whole step tuning is commonly used by artists such as Metallica and Iron Maiden so make sure to adjust your tuning to best fit the song.
Many other guitar techniques are adopted in metal music such as dive-bombs (primarily from floyd-rose tremolo bridges) bends, hammer-ons, tapping and pinched harmonics.