From its emergence in the early 1970s, heavy metal evolved into the collective of interrelated strands recognised as metal today. It is an extensive and ever-growing network that includes, amongst others, classic metal, thrash metal, black metal, death metal, melodic death metal, folk metal, symphonic metal, grindcore, metalcore, deathcore, nu metal, doom metal, progressive metal, industrial metal, gothic metal and djent. Whereas the nomenclature and boundaries are somewhat arbitrary, those strands are united by the common espousal of specific musical practices and performance techniques contributed by key bands and performers over the last five decades. It is a process that seems to fall naturally into three stages, which will be explored in this chapter: formation, expansion and fusion.

Formation

Many of the core features of metal to date first emerged in the early live performances and studio album tracks of Black Sabbath.¹ Hailing from Aston (Birmingham, UK) in the industrial heartlands of England, vocalist Ozzy Osbourne, guitarist Tony Iommi, bassist Geezer Butler and drummer Bill Ward took inspiration from the occult-centred writings of Dennis Wheatly and the Hammer horror film series, espoused the name Black Sabbath and created a lyrical and musical world that was in every way as dark, morbid and other-worldly as the cinematic and literary genres that inspired it. Lyrics not only engaged with the arcane world of gothic horror, paganism and fantasy but also displayed a growing interest in anti-war and anti-patriarchal rhetoric. It was an influential approach that inspired album art, dress codes, band names (Cradle of Filth, Deicide, The Haunted, System of a Down) and a wide range of lyrical interpretations² from Iron Maiden’s macabre ‘Hallowed be Thy Name’ (1982) to Metallica’s nightmarish ‘Enter Sandman’ (1991), Sepultura’s polemic ‘Refuse/Resist’ (1993) and the Satanic atheism of Opeth’s ‘The Grand Conjuration’ (2005). It was an approach best summed up by Osbourne when he said: ‘For us the whole hippy thing was bullshit. The only flower you saw in Aston was on a gravestone. So we thought, let’s scare the whole f**king planet with music.’³

Musically, Black Sabbath expressed that notion through a number of different compositional and performance-related strategies, all of which became central to the sound of heavy metal. Arguably, the most immediate of those were the band’s aggressive performance techniques and extreme levels of amplifier volume.⁴ Although a process initiated in the work of 1960s rock bands such as The Who and The Jimi Hendrix Experience,⁵ Black Sabbath took it further by combining high-output distortion with a particularly brutal form of attack that seemed to mirror the architecturally decimated and industrial post-war environment from which they emerged.⁶ Those muscular riffs were underpinned by Bill Ward’s powerful and innovative drumming style, which paid scant regard to the established timekeeping and backbeat-focused⁷ traditions of rock drumming and, instead, adopted an approach that often closely integrated with the shape of the compositions. For example, on the recordings ‘Black Sabbath’ and ‘Iron Man’ (both 1970), Ward’s drumming emphatically traces the rhythmic contours of the guitar parts to intensify the visceral punch of those riffs. When Ward does incorporate backbeat-type features, it is much more to do with riff propulsion and symphony rather than timekeeping and dancing. That innovative approach redefined the role of the metal drummer, something more fully illustrated further on.

A guitar-specific metal characteristic to emerge at the same time was that of down-tuning, a tuning method where the standard pitch of a guitar is lowered in nominated increments of half steps or, more correctly, semitones. Down-tuning is not specific to metal, but when combined with brutal performance techniques and high-gain tones, it forms a context that is peculiar to metal. Tony Iommi first adopted that practice because of an unfortunate machine shop accident in which he lost the tips of his fretting hand middle and ring fingers. He did so initially to make playing more comfortable – slacker strings are more pliable and softer on the fingers. However, having seemingly discovered the inherent darkness of timbre that results from such low-pitched guitar strings, especially when combined with the loud, high-gain amplifier output and brutal performance style discussed earlier in this section, the band eagerly incorporated that practice into the fabric of their signature sound.

Although Black Sabbath’s first two albums were recorded with the guitars tuned to standard pitch, all live performances during that time were in E flat standard, which is one semitone lower. From the release of their third album, Master of Reality (1971), they not only committed to recording with the guitars down-tuned but also expanded the concept by dropping the pitch three semitones to C sharp standard for certain tracks, as in, for example, ‘Children of the Grave’ (1971), ‘Under the Sun’ (1972) and ‘Symptom of the Universe’ (1975). Although not all metal bands followed Black Sabbath’s example by adopting, centralising and privileging down-tuning methods, most have, and that ubiquity is abundantly evident across the metal collective, a point more fully illustrated further on.

Synonymous with down-tuned heavy metal riffing is the power chord,⁸ a key performative and compositional tool that, according to metal mythology, also originated as a direct corollary of Tony Iommi’s accident. Unable to play barre chords in the conventional way following that life-changing incident, Iommi took to fretting just the two lowest notes of a regular barre chord using his unaffected index and little fingers, and the result was a simple two-note chord, five notes apart – a spacing known in musical terms as a perfect 5th.⁹ He moved those two-note shapes up and down the fretboard to iterate the chord changes, and et voila, the power chord sequences of heavy metal were born. By composing riffs from sequences of 5ths, Iommi had invoked an age-old medieval device known as organum, something that went out of fashion many centuries ago but now repurposed as part of Black Sabbath’s agenda to, as noted earlier in this section, ‘scare the whole f**king planet with music’ – unholy transgression indeed.

Equally important to the compositional processes of Black Sabbath, and of heavy metal thereafter, are monophonic phrases and motifs which work in tandem with power chords to provide the essential riff-centred core of metal’s instrumental skeletal framework. It is an approach that highlights the conspicuous and notable absence of traditional chord progressions in metal, a remarkable phenomenon that emerged from Iommi’s subversive approach to harmony, and one of the most striking features of the genre. Whereas it is recognised that metal bands make occasional or novel use of traditional harmonic movement, those instances, with the exception of fusions such as folk metal,¹⁰ are aberrant within the wider context of their repertoires. Similarly, the eschewal, or down-playing, of pentatonic and blues stylisations in favour of modal syntax is equally striking. This, too, is a characteristic that originated in the early work of Black Sabbath, where the judicial privileging of specific medieval church modes¹¹ significantly contributed to articulations of the arcane and other-worldly aesthetics of their lyrical subjects. More specifically, they drew on the Aeolian, Dorian and Mixolydian modes to evoke gothic ambience and the rather eery-sounding Locrian mode to express fear, discomfort and discord.

For example, within the Locrian mode is found the tritone, a musical device known colloquially as Diabolus in Musica (‘the devil in the music’). In ‘Black Sabbath’ (1970), the ominous ‘figure in black’ is made terrifying by the prominent reiteration of tritones. Those tritones are also multiplied across the texture of the music being heard in the guitar riffs, bass lines and tortured vocal parts of Osbourne. An equally distinctive feature of the Locrian mode is the very piquant flat 2nd,¹² a musical interval that dominates much of ‘The Wizard’ (1970) from the same album. In other places, flat 2nds are iterated in sequences to produce tense chromatic lines such as those found in ‘War Pigs’ (1970). From within the many creative configurations of those discordant musical devices emerged an unusual ‘angular’ style of writing that became the cornerstone, not only of Black Sabbath’s own signature sound but of the whole, sonic edifice of metal itself, a ubiquity too monolithic to summarise here but represented by tracks as wide-ranging as Metallica’s ‘Enter Sandman’ (1991), Pantera’s ‘Walk’ (1992), Machine Head’s ‘Old’ (1994), Drowning Pool’s ‘Bodies’ (2001), Rammstein’s ‘Sonne’ (2001), Lamb of God’s ‘Laid to Rest’ (2004), DevilDriver’s ‘Hold Back the Day’ (2005), Amon Amarth’s ‘Free Will Sacrifice’ (2008), Slipknot’s ‘Psychosocial’ (2008) and Judas Priest’s ‘Necromancer’ (2018).

Expansion

As much as those tracks embody and perpetuate the compositional methods, brutal performance practices and lyrical themes initiated by Black Sabbath, clearly, there are a whole range of additional stylisations evident in those recordings that reveal a significant post-Sabbath expansion of metal coding. Such features include new performance practices such as vocal growling, guitar tremolo picking, drumming double kicks and blast beats, complex twin-guitar textures and significant advancements in sound technology. The inception of that process occurred during the latter half of the 1970s within the so-called New Wave of British Heavy Metal (NWOBHM).¹³ It was a movement spearheaded by bands such as Iron Maiden, Judas Priest, Venom and Motörhead, who each built on select elements of Black Sabbath’s unique coding to forge novel, metal-influenced identities. However, it was during the 1980s and 1990s that the techniques and lineaments noted earlier in this section synchronised with those earlier innovations to form the full range of metal coding recognised today.

One of the most notable developments of that formative period was an expansion of Bill Ward’s integrated and orchestral approach to drumming, along with an elevation of the metal drummer to that of a highly specialised erudite technician. It was a process marked by the introduction, advancement and adoption of a range of new techniques, including double kick or double bass pedalling. This stylisation became the norm in many strands of the heavy metal collective and involves the use of two separate bass drum pedals to create fast and intricate mechanistic patterns that both propel the music and, often, synchronise with the guitar parts in a profuse assortment of configurations. Examples include Slayer’s ‘Raining Blood’ (1986), Machine Head’s ‘Davidian’ (1994), Strapping Young Lad’s ‘Love?’ (2005), Grand Magus’ ‘Kingslayer’ (2005), Ensiferum’s ‘In My Sword I Trust’ (2012) and In Flames’s ‘Burn’ (2019).

It was, in fact, Bill Ward who first indicated the future heavy metal context of double kicks in a brief passage of thundering double bass work, starting at 3:08, on ‘Into the Void’ (1971). Ward took his cue from the work of Louis Bellson, a drummer famed for his use of double kicks with the Duke Ellington band during the 1950s (for example, ‘Skin Deep’, 1952). Ian Paice of Deep Purple also pointed the way in ‘Fireball’ (1970), a recording that significantly influenced Judas Priest’s ‘Exciter’ (1978) and Motörhead’s ‘Overkill’ (1979), both of which were important landmarks in the evolution of metal drumming. Rob Hunter of Raven developed an even greater intensity of speed and drive on tracks such as ‘Tyrant of the Airways’ (1981); however, it was Dave Lombardo of Slayer whose catalytic development of that technique, for example, in Slayer’s ‘Haunting the Chapel’ (1984), led more directly to the complex refinements and almost complete ubiquity found in metal today.

A second widespread development in metal drumming was the emergence of the blast beat, a single stick roll or rapid alternation of bass and snare drum – essentially, a fast backbeat or polka beat – synchronised with cymbals. The true blast beat seems to have first emerged in the mid-1980s with tracks such as ‘Milk’ (1985) by Stormtroopers of Death, but it was Motörhead who initiated the exponential acceleration of the backbeat tempo on recordings such as ‘Ace of Spades’ (1980). United Kingdom’s hardcore punk innovators, Discharge, intensified that trend (for example, ‘The Blood Runs Red’, 1982), a process mirrored in the United States in the work of San Francisco’s Dead Kennedys on their 1981 album In God We Trust, Inc. Those recordings were highly influential on bands such as Slayer and Metallica, key instigators of thrash metal. However, the most extreme form of blast beat is more readily associated with Napalm Death and the early grindcore movement,¹⁴ where the superfast backbeat patterns of hardcore morphed into what was, essentially, a stylised arhythmic and non-metric blast of sonic violence. By the early 1990s, the blast beat, and its numerous variants, had evolved into a discrete and metronomically precise musical technique requiring astonishing levels of stamina and virtuosic skill, much like double kicks. More importantly, those stylisations became essential components in many strands of the metal collective, exemplified by such tracks as At the Gates’ ‘The Red in the Sky Is Ours’ (1990), Cradle of Filth’s ‘Mother of Abominations’ (2004), As I Lay Dying’s ‘Comfort Betrays’ (2007) and Napalm Death’s ‘F**k the Factoid’ (2020).

Whilst metal drummers were busily fashioning such distinctive new characteristics, their fellow guitarists were equally industrious in developing their own range of new stylisations. Such developments included the adaptation of a long-established folk guitar technique known as tremolo picking, a method involving rapid alternation of the plectrum to achieve a peculiar type of sustain. It was 1960s surf guitarists like Dick Dale who first remodelled that quaint folk technique within a rock context on tracks such as ‘Misirlou’ (1962). In metal, however, tremolo picking received a radical makeover, becoming a genre-specific technique used to both intensify aggression and mirror the double kick rhythms of the drummers. In this way, guitars and drum kit work in symphonic unison to accentuate the impact of the riffs. Examples include Slayer’s ‘War Ensemble’ (1990), Cradle of Filth’s ‘Cthulu Dawn’ (2000), As I Lay Dying’s ‘The Sound of Truth’ (2007) and Amon Amarth’s ‘Live Without Regrets’ (2011).

One further way in which guitarists contributed to the development of metal during this second stage of evolution was through the creative ontogeny of twin-guitar work. At the forefront of this initiative were Iron Maiden and Judas Priest who, building on the innovative 1970s work of Wishbone Ash and Thin Lizzy,¹⁵ designed complex harmonic and contrapuntal¹⁶ textures for twin guitars that merged effectively with their own unique take on the other-worldly/anti-war lyrical themes and modal syntax initiated by Black Sabbath.¹⁷ Examples include Iron Maiden’s ‘Hallowed Be Thy Name’ (1982) and ‘The Trooper’ (1983), along with Judas Priest’s ‘Tyrant’ (1976) and ‘Exciter’ (1978). It was an approach that suited heavy metal’s proclivity for complex design,¹⁸ both in formal structure and in textural detail,¹⁹ a trend widely embraced throughout the metal collective and illustrated by a wide range of examples, including Metallica’s ‘One’ (1988), Megadeth’s ‘Hanger 18’ (1990), In Flames’ ‘The Jester’s Dance’ (1996), Machine Head’s ‘Slanderous’ (2006), Cradle of Filth’s ‘Nymphetamine Fix’ (2004), Slipknot’s ‘Vendetta’ (2008), Týr’s ‘Hold the Heathen Hammer High’ (2009), Amon Amarth’s ‘First Kill’ (2016) and Carcass’ ‘The Living Dead at the Manchester Morgue’ (2020).

Guitarists’ innovations were also driven by the desire to find ever-increasing extremes of down-tuning and distortion too. Whereas Black Sabbath had frequently down-tuned to C sharp standard, others, led by bands such as Carcass (for example, Reek of Putrefaction, 1988) and At the Gates (for example, The Red in the Sky Is Ours, 1992), took that principle further, lowering the pitch a huge five semitones to B standard. Since then, both C and B standard have become common across the metal collective. Additionally, many guitarists adopted ‘dropped-tuning’ – standard tuning (at standard pitch or any of the down-tuned equivalents), with the sixth string tuned one whole step lower. The string spacing between the sixth and fifth string in this method allows a power chord to be performed using a short barre with just one finger and, therefore, a faster and more efficient method of iterating that key metal device. Examples include Pantera’s ‘Walk’ (1992) (dropped D) and Disturbed’s ‘Down with the Sickness’ (2000) (dropped C). At the same time, guitarists eagerly pursued greater refinements of tone and power to drive those power chords, riffs and solos. Electronics developed accordingly with amplifiers and effects pedals emerging that could simulate highly saturated distortion, something amply illustrated in the previous examples.

One of the more radical developments of post-1970s metal was the emergence of new vocal techniques, particularly in the rabid screams and death growls that both originated on and are synonymous with the underground extreme metal scene. It was a process that began with Venom and Motörhead who, in a departure from the expected norm of tuneful intonation, engaged with a more raucous and monotone approach to vocalising in numbers such as Motörhead’s ‘Jailbait’ (1980) and Venom’s ‘Black Metal’ (1982). The vocals of Slayer and Death in the early 1980s intensified and broadened that approach pre-empting the wide range of rabid vocal stylisations that came to dominate much of the metal scene thereafter. That range encompasses all levels of pitch, from deep, guttural death growls through mid-range frenzied rasps to theatrical high-pitched screams.

Cradle of Filth vocalist Daniel Davey, aka Dani Filth, impressively covers the whole gamut of those stylisations, often within the confines of a single composition, something evidenced on ‘Cruelty Brought Thee Orchids’ (1998). Similarly, but in a less theatrical setting, Angela Gossow, in her time with Arch Enemy, not only helped establish the strong tradition of female growlers on the scene today but also developed a remarkably wide range of pitch in her brutal live and recorded performances. Others have chosen to specialise in one range or another. Johan Hegg (Amon Amarth), Mikael Åkerfeldt (Opeth) and Glen Benton (Deicide) favour low-pitched death growls, whilst vocalists such as Randy Blythe (Lamb of God), Corey Taylor (Slipknot and Stone Sour) and Rob Flynn (Machine Head) are noted for their mastery of ferocious mid-range snarls.

Of course, not all metal vocalists have embraced the idiomatic trend for the growled, snarled and screamed, preferring, instead, to engage with a more traditional and melodic approach, one that both perpetuates and enhances the vocal histrionics initiated by Rob Halford (Judas Priest) and Bruce Dickinson (Iron Maiden). Notable proponents of this approach are Joakim Brodèn (Sabaton), Janne Christoffersson (Grand Magus) and Heri Joensen (Týr). Also important in contributing to the same tradition are the many prominent female vocalists of the metal collective, a roster that includes Tarja Turunen (solo artist and ex-Nightwish), Floor Jansen (Nightwish and After Forever), Liv Kristine (Leaves’ Eyes and various metal collaborations), Sarah Jane Ferridge, aka Sarah Jezebel Deva (Cradle of Filth collaborations), Cristina Scabbia (Lacuna Coil) and Doro Pesch (solo artist).

Fusion

By the early 1990s, then, the core coding of metal was established and, although the future trajectory would see ever-increasing levels of complexity and sophistication applied to those established codes (as in mathcore and djent, for example), metal, thereafter, would evolve by means of fusion or hybridisation. It was a process that occurred on two levels. Firstly, by the fusion of contrasting stylisations from within metal itself and, secondly, by the incorporation of elements taken from pop, folk, classical and other forms of music normally considered incongruous with metal.²⁰ In this way, bands were able to establish novel identities within the metal scene and explore new ways of evolving the metal genre. It is important to note that there was considerable overlap in the dual processes of expansion and fusion.

Given the bifurcation of vocal techniques that occurred during the second stage of metal’s development, it was natural that metal musicians would seek to combine those highly contrasting techniques, something educed by Los Angeles band Fear Factory in their pioneering work in the early 1990s. Their vocalist, Burton C. Bell, developed a style that moved easily between juxtaposed sections of growled/screamed vocals and melodic singing, almost as if it were two different singers. It was an approach prefaced on their early recordings but more fully realised on their 1995 album Demanufacture. From the mid-1990s, notable outfits such as System of a Down and Slipknot grew that trend to become commonplace within the metalcore and melodic metalcore scene of the 2000s, a movement further developed and represented by such bands as Machine Head, Trivium and Bullet for My Valentine. Whilst those artists adopted the same episodic approach as Fear Factory, others have been more creative. For example, As I Lay Dying, on the track ‘I Never Wanted’ (2007), used three vocalists in a more integrated and contrapuntal way by combining growled/snarled vocals simultaneously with melodic singing and traditional two-part harmonies in an effective three-part ensemble that smoothly transitions between numerous textures and colours.

A more heterogeneous fusion of idioms occurs in the diverse world of nu metal, where elements of metal, hip-hop, industrial, funk and pop coalesce in a range of permutations and unique metal makeovers.²¹ Korn were one of the earliest progenitors of that concept, but it was Limp Bizkit who, through their incorporation of funk grooves, hip-hop rapping and DJ scratching, helped shape the more commercial approach often associated with that style. The band’s 1999 award-winning single ‘Break Stuff’, for example, gives the Diabolus in Musica guitar riff of the verse sections a funky makeover in its supporting role to Fred Durst’s stylised rap technique – an incongruous, yet effective and unique contribution to the ever-expanding family of metal idioms. Linkin Park further exploited the commercial potential of that concept on their albums Hybrid Theory (2000) and Meteora (2003). Those recordings spawned a number of singles that blended elements of metal, pop, industrial and hip-hop into a unique metal-focused style with widespread global appeal. In ‘Numb’ (2003), for example, a creative counterpoint of rapping and strongly emotive vocal melodies weave through a rhythmic flow of highly contrasting dynamics and industrial keyboard sounds to deliver what may best be described as a metal-centric ballad. Even where Linkin Park focus more on the metal elements, as in their 2000 release ‘One Step Closer’, gentle melodic and rap vocal techniques temper the presence of rabid vocals, dropped-tuning, high-gain distortion, Black Sabbath-influenced angular syntax and prominent Locrian discords.

A common approach shared by nu metal bands such as Linkin Park and Limp Bizkit is a proclivity for the verse/chorus-style formatting found in much pop music, a tendency also evident, perhaps surprisingly, in the more guitar-centric circles of nu metal. For example, Drowning Pool’s 2001 mosh pit favourite, ‘Bodies’, is not only verse/chorus/middle-8-led, but a strongly anthemic crowd-pleaser too. However, the prominence of metal syntax, timbres and vocal techniques eclipse any genuflections towards pop stylisations, an approach similarly encountered, for example, in Papa Roach’s ‘Last Resort’ (2000) and ‘Between Angels and Insects’ (2000), and also Five Finger Death Punch’s ‘Jekyll and Hyde’ (2015) and ‘Sham Pain’ (2018).

For many metal musicians, romantic notions of bygone eras, traditional folklore and indigenous cultural practices have inspired a plethora of folk metal crossovers. This concept has been particularly strong in Western Europe and Scandinavia, where a proclivity for Celtic folk melody easily aligns with the modal syntax and medieval aesthetics already established in mainstream metal.²² Within those numerous configurations, there are varying emphases placed on the folk elements. For example, in the so-called Viking metal of Nordic bands Amon Amarth and Ensiferum, lyrics and visual imagery are highly significant and hold parity with the modal-centric musical elements. Amon Amarth’s 2016 hymnal anthem ‘The Way of Vikings’ praises the glorious might and bravery of the Viking warrior with noble and majestic folk melodies, archaic harmony, death growl vocals and other extreme metal characterisations. A similar approach marks Ensiferum’s 2012 track ‘In My Sword I Trust’. There, the rabid vocals and stirring synthesised choral lines give way to a rousing esprit de corps refrain, calling brothers to arms with triumphal melodic leaps. Finntroll celebrate their Finnish roots in a more playful way. Their 2004 track ‘Fiskarens Fiende’, for example, both parodies and subverts the Finnish folk dance known as ‘humppa’. The song is underpinned by archetypal walking ‘oompah’ bass lines and (simulated) accordion parts of the humppa and overlaid with creepy-sounding Locrian motifs, rabid vocals, down-tuned, distorted guitars and double kicks to complete the quirky caricature.

Others have focused more on the incorporation of actual traditional instruments and performance techniques as a way of hybridising folk and metal. For example, Danish band Svartsot, building on the earlier work of England’s Skyclad and Ireland’s Cruachan, successfully combine metal stylisations such as death growl vocals, double kicks and distorted, down-tuned guitar riffs with traditional Celtic instruments such as the Irish whistle, Aeolian pipes and Bodhran. On Svartsot’s 2007 track ‘Gravollet’, for example, the instrumental modal themes are shared equally between metal guitar and Irish whistle, and the spirit of a traditional ceilidh dance is clearly invoked by the skipping pseudo-bodhran rhythms of the opening and the polyrhythmic hemiola cadences of each section. Whilst fellow Scandinavian bands Turisas and Korpiklaani have followed a similar trajectory, the Scottish pirate metal band Alestorm have accommodated an even wider range of acoustic instruments in the creation of their rather quirky and subversive take on folk metal. Such instrumentation has not only included passages for fiddle, accordion and tin whistle but also for trombone, trumpet and vibraslap, a rich timbral pallet evidenced across their output, including their 2014 album Sunset on the Golden Age.

Although strongly Eurocentric, folk metal has developed globally too. For example, Israel’s Orphaned Land blend metal coding with Middle Eastern syntax and dance rhythms along with the incorporation of idiomatic instrumental and vocal traditions, a styling abundantly evident on All Is One (2013). Taiwanese band Chthonic have significantly impacted the global metal scene with an innovative fusion of Orient folk and black metal. This is expressed through the telling of ancient and recent Taiwanese history along with the incorporation of East Asian instrumentation such as the Chinese erhu and Japanese koto. Those elements are well exemplified throughout the 2011 album Takasago Army.

Classical music has provided metal musicians with alluring opportunities for assimilation from the start; Black Sabbath’s theatrical and structurally complex approach owes much to the world of Romantic-era music, and the layered tritones of ‘Black Sabbath’ (1970) itself were directly influenced by Gustav Holst’s ‘Mars’ from The Planets (1914).²³ The theatrical and pseudo-operatic vocal style of Rob Halford of Judas Priest, for example, on Stained Class (1978), further strengthened metal’s affiliation with classical music, an approach magnified in black metal where vocal histrionics combine with prominent orchestral and operatic keyboard sounds to significantly define the esoteric soundscapes of bands such as Cradle of Filth and Dimmu Borgir. However, it was in the work of Finland’s Nightwish where the most overt interpretation of symphonic metal emerged on albums such as Oceanborn (1998) and Wishmaster (2000). The appointment of trained opera singer Tara Turunen and prominent use of synthesised orchestral parts on those albums emphatically signalled the band’s intent to forge a classical/metal hybrid that was in every way as artistically grand in performance and composition as the symphonic muse that inspired it.

In a similar way, industrial references have been central to metal from the beginning, particularly in the mechanistic rhythms of the drum and guitar parts. Nevertheless, several artists have forged more discrete and genre-specific hybrids of industrial metal, including Fear Factory, Nine Inch Nails, Rob Zombie, Marilyn Manson and the German band Rammstein. In concert, Rammstein have staged a series of settings that play with themes of industrial desolation and deprivation redolent of the former German Democratic Republic from which they emerged. The extensive use of pyrotechnics has been central to those productions and seen guitarists breathing fire, flaming mic stands, a firework-shooting crossbow, burning metallic angel wings and flames from stage pyro canons that fire with all the searing intensity of an industrial blast furnace.

Rammstein are also synonymous with the emergence of dance metal,²⁴ a crossover style that combines metal with electronic dance music idioms such as techno and ambient. That fusion is most readily recognised in their 1997 MTV hit ‘Du Hast’, where a techno-style ‘four to the floor’ bass drum beat is overlaid with gated loops, sustained, ambient keyboard chords, robotic, space-age synth tones and high-gain, drop-tuned heavy metal guitar riffing. An even greater interest in hybrid experimentations is evidenced within the remainder of Rammstein’s extensive output, where a variety of unusual combinations may be found in addition to their industrial and dance metal offerings. For example, ‘Te Quiero Puta!’ (2005) combines brutal heavy metal riffing with pseudo-Tijuana brass, flamenco syntax and a quirky vocal contribution from Hispanic born Hollywood star Carmen Zapata. It is a spectacular and innovative fusion that generates intense discord by the simultaneous mix of Phrygian, Phrygian dominant²⁵ and Locrian elements whilst, at the same time, exuding playful and subversive humour.

The multi-hybrid style adopted by Rammstein foreshadows the most recent trends in metal, which take the concept of fusion to extreme levels, an approach spearheaded by Pittsburgh quintet Code Orange. Their 2020 album Underneath combines sound effects and samples with a huge range of metal stylisations and other related idioms. That pallet includes, amongst others, industrial, mathcore, thrash, grunge, electronica, ambient, metalcore, hardcore, djent, doom, sludge, black metal, death metal and progressive rock. It is an experimental and truly avant-garde approach that juxtaposes those highly contrasting stylisations in rapidly changing episodes to delineate a scrambled montage of sound that animates the subversive and often nightmarish content of their lyrics and videos.

As such, the work of Code Orange in 2020 reminds us that Black Sabbath’s original agenda, back in 1970, to ‘scare the whole f**king planet with music’, is just as relevant today as it was fifty years ago. Furthermore, whereas metal has widely diversified during the course of its evolution, it is the core coding established by Black Sabbath and other early innovators that continues to both unify and identify the current diverse world of heavy metal music.