In October 1969, Black Sabbath recorded their debut album in a single day-long session at London’s Regent Sounds Studio. Especially when compared with the affordances of today’s digital music production technology, the conditions were rudimentary: the studio had a four-track tape machine that allowed drums, bass and guitar to be tracked, then a separate guide vocal or second guitar, which were later merged to make space for vocals or additional guitar parts. Importantly though, these limitations did not, in any way, obscure the core ingredients for what was to become ‘the sound of metal’. The heavily distorted guitars were recorded at excruciatingly loud levels and double-tracked to fill out both sides of the stereo field and create a wall of sound. The bass guitar was distorted – uncommon for the time – and primarily followed the guitar riffs to give them weight and heaviness. Whereas contemporary hard rock bands recorded multiple guitar parts to embellish melodies or play counterparts, Black Sabbath’s arrangements and production approach aimed at maximising heaviness through sonic weight.

Though considered a fundamental quality of the music, it is unclear what exactly ‘heaviness’ is, not least because of its ambiguous, context-specific and subjective nature. According to Harris M. Berger, metal ‘history is most often summed up by metalheads as a progressive quest for ever-heavier music. A rich and complex concept differentially interpreted across scenes, “heavy” refers to a variety of textural, structural, and affective aspects of musical sound and is crucial for any understanding of metal’.¹ There are indications that this quest for heaviness began with the birth of metal. Tony Iommi reflected in his autobiography that where Led Zeppelin relied on powering drums, Black Sabbath focused on a ‘massive guitar and bass wall of sound’, aiming to ‘out-heavy Led Zeppelin’.² Francis Rossi, frontman of Status Quo, pointed out that in competition for heaviness in the early 1970s, no other band but Sabbath achieved such a thunderous and weighty sound.³ Little has changed in the more than fifty years of metal music; bands still claim that their latest record is heavier than anything they have released before, seeing increased heaviness as a signifier of improvement and proof of not having sold out.

Heaviness seems to be a combination of compositional elements, performative features and sonic characteristics. Structural aspects, most of all perceived tempo and pitch, are essential contributing parts. Their realisation through performance is equally important, as only powerful playing and tight ensemble synchronisation create the individual and collective sounds perceived as heavy. In recorded form and on the live stage, technological mediation has increasingly helped metal artists in their enduring quest for greater heaviness. The decisive role of technology becomes apparent when comparing metal releases from different periods. While songs and performances have certainly changed, the quality and aesthetics of the produced sound have significantly altered metal’s sonic signature.

This chapter gives a historical overview of the development of heaviness on metal records by tracing how specific releases set standards or trends in metal music production. It focuses on early heavy metal, the thrash metal movement in the 1980s and the beginning of extreme metal in the early 1990s, concluding with an outlook of contemporary and future production aesthetics.

Early Heavy Metal

The production possibilities for Black Sabbath’s debut album were limited by both the recording technology of the time and engineers unfamiliar with the new, heavy aesthetic. But recording technology evolved rapidly and satisfied the consumers’ growing hunger for heavier sounds. Most recording professionals had to learn how to harness ever-evolving production tools to effectively produce the increasingly more extreme forms of metal, which required different approaches than rock music. Partly due to the general willingness to engage with the relevant challenges and to explore, new metal-specific production approaches developed quickly.

Black Sabbath’s second album, Paranoid (1970), was already produced with 24 tracks and more studio time, allowing greater freedom to craft the band’s heaviness aesthetic. On their third album, Master of Reality (1971), the band emphasised sonic weight by tuning the guitars and bass down by three semitones for ‘Into the Void’, and in the process, laid the foundations for an often-default subsequent trend.

Other now-iconic metal bands also contributed to the advance of heaviness through pioneering performance and production styles on their influential releases in the 1970s and 1980s: British acts Judas Priest, Motörhead and Venom, to name a few. Although the distinction between hard rock and heavy metal was blurred in the 1970s, a specific metal aesthetic began to formulate. The grim and doomy atmosphere of Black Sabbath and the guitar/vocal virtuosity of Deep Purple and Judas Priest combined provided a performance template for many aspiring metal bands. Elsewhere Motörhead and Venom somewhat tore up or at least heavily revised this formula, and in the process, provided inspiration for thrash and extreme metal.

Bands, engineers and producers experimented with new forms of expression. A major step towards a heavier aesthetic was enabled by introducing two kick drums or double kick pedals on a single kick. Although jazz drummers and rockers like Cream, The Who and Rush had already experimented with this approach in the 1950s and 1960s, respectively, metal increasingly built its aesthetic around fast kick drum subdivisions. As exemplified on their second album, Overkill (1979), Motörhead drummer Phil Taylor was one of the earliest metal performers to fully exploit this technique. According to Overkill’s engineer Trevor Hallesy, ten of the 24 available tracks were used for drums, and the double kick was deemed important enough to be recorded with two microphones so that other essential instruments like the snare had to be captured with one microphone only.⁴ The additional weight from the more prominent kick drum performance was particularly well-suited to the quest for greater heaviness. Evidence that the kick’s role was rapidly growing is provided by engineer Tony Platt, who remembered the drum microphone setup for Motörhead’s Another Perfect Day (1983). Pre-empting the modern practice of layering different kick drum microphones to control the high-end click, mid-frequency thump and sub-bass power, a valve microphone was blended with standard dynamic kick microphones to capture the sub-frequencies in a manner that reproduced the impact of moving air.⁵

Triggering, a technique allowing to add samples to the drum sound for more punch, was already available in the 1980s, before recording became digital. Studio reports on bands like Judas Priest and Motörhead nevertheless suggest that producers and bands avoided triggering drums and instead aimed to improve drum performance and recording quality. Whether ethical considerations prevented them from employing sampling technique is uncertain. According to producer Chris Tsangarides, and regardless of ethical considerations, numerous Judas Priest albums prior to Painkiller (1990) relied in part on programmed drums.⁶ Such precise half-programmed drumming preceded the quantised drum sound that became common in the 2000s.

While the kick drum was generally gaining importance, one band experimented with the snare drum: Venom. For metal journalist Joel McIver, Venom drummer Tony Bray (Abaddon) invented thrash metal by doubling the speed of the snare, featured first in ‘The Witching Hour’ on Venom’s debut Welcome to Hell (1981): ‘It’s that snare drum pattern which is the essence of thrash metal … Abaddon’s drum part … was much faster than the usual rock and metal drum patterns, and now typifies the basis of all extreme metal.’⁷ This release marked the beginning of a race for faster performances, soon to be exploited by thrash bands from the US (Metallica, Slayer, Exodus) and Europe (Kreator, Sodom, Destruction), and an increase in heaviness.

As for the bass, Judas Priest and Motörhead continued Black Sabbath’s tradition of supporting the guitar, an aesthetic still prevalent in many modern metal productions. Lemmy Kilmister of Motörhead played his bass through guitar amplifiers with the treble turned up and the bass removed, much to the frustration of the band’s engineers and producers. As Trevor Hallesy remembers: ‘My bottom-end challenge came more from the bass drums than the bass really because Lemmy’s playing is more of a guitar-playing style than a bass-playing style – you have to use the drums for bottom end. So if you listen to Motörhead, the bass drums are really pounding away there and the bass is almost another guitar part.’⁸ Ryan Dorn similarly pointed out that even the guitars had more bottom-end than the bass.⁹ This was not much different with Judas Priest. As Tom Allom remembered: ‘I used to say they were the band with no bass player, as the bass kind of followed all of the parts of the guitar. It was the fatness of the guitar sound that I liked most about those Priest albums.’¹⁰ The engineers and producers of both bands found creative ways of dealing with this problem. On Motörhead’s Another Perfect Day (1983), Tony Platt split the bass signal to be recorded with different microphones through guitar and bass amplifiers to blend the instrument’s low-end with the distorted sound of the guitar amplifier.¹¹ This technique has become standard in contemporary metal production. Judas Priest with producer Tsangarides employed a similar strategy on Painkiller (1990), but instead of mixing two amplifiers, they doubled the bass parts with a Moog synthesiser to receive the pick attack from the bass guitar and the low-end from the synthesiser.¹²

Guitars continued to be the backbone of metal in the 1970s and 1980s. Engineering practice hardly changed aside from the fact that higher track counts allowed two microphones, one for low-end and one for clarity and presence. Recording one guitar each for the left and right channels remained common. Some productions added ambience microphones (Judas Priest’s Painkiller, 1990)¹³ or short delay effects (Motörhead’s Another Perfect Day, 1983)¹⁴ to thicken the guitars.

Thrash Metal

Thrash metal’s emergence and proliferation in the 1980s complemented the development of metal music’s heaviness, with artists from the newly formed sub-genre not only competing for heaviness, as was the case in the 1970s, but now also for speed. Metallica’s debut, Kill ‘Em All (1983), marked a significant increase in speed, far surpassing the previous standards set by Motörhead. Tom Warrior of Celtic Frost noted that the new US-American thrash metal bands ‘had a much more clinical approach to heaviness. Whereas the British bands had this publike aura around them, the Americans just sounded like heavy machines’.¹⁵ Performances became faster and tighter and thus more effective, supported by new affordances in production technology. While the debuts of most thrash bands were raw, energetic and passionate, subsequent albums increasingly exploited overdubs recorded to a click track, alongside tape editing and punch-ins to craft clinically precise performances that were, from Metallica producer Flemming Rasmussen’s perspective, almost ‘computer-accurate’.¹⁶ Partly due to metal artists now seeing their album’s production aesthetics as an integral part of their art, metal music’s overall production standards increased considerably.

In favour of a more direct and aggressive sound, an important departure from the earlier rock aesthetic was the decreased reliance on recorded or synthetic ambience. Eschewing reverb for an improved sense of clarity, Slayer’s Reign in Blood (1986), as just one example, translated the band’s aggressive style far better than their previous two albums.¹⁷ Here it can be noted that, due to the fast performances (the album features ten songs delivered within 29 minutes), there was limited ‘space’ for ambience to exist and expire within, and the same can be said of slower low-frequency wavelengths. According to metal journalist Ian Christe, it was the ‘first time that Slayer’s sharp speed … was not dampened by muffled, dime-store production values’.¹⁸ Metallica’s transition to a dry and direct sound began with their second record, Ride the Lightning (1984), and culminated on their fourth album … And Justice for All (1988). Although the latter album divided some fans due to its extremely dry and clinical sound, the record, and especially its dry drum aesthetic, was highly influential. Producer Rasmussen noted that no room microphones at all were used, and neither was reverb added in the mix.¹⁹

Drum samples were seldom employed in the major productions of the 1980s and early 1990s. They were not used on Metallica’s first four albums nor on early records of other influential bands like Pantera,²⁰ at least according to claims of the respective engineers and producers.

Alongside the development of drum recording, editing and processing techniques, guitar engineering progressed significantly, itself becoming an art form. Thrash metal built an entire style around fast palm-muted guitar lines, resulting in a production requirement that adequately captured these fast and precise performances and translated them with the optimum balance between sonic weight and clarity. Rasmussen recalled the guitar tracking for ‘One’ on Metallica’s … And Justice for All (1988) one of the most ‘produced’ metal guitar sounds of the 1980s: ‘The guys were in a layering mode, aiming for perfection … By the end of the song there were six or eight rhythm guitars, played by James [Hetfield] on different amps with different sounds on top of each other. However, he was so tight that this just sounded like one big wall of guitars.’²¹ In some respects, though, the guitars were not too different from earlier productions. They were still double-tracked, one left and one right, and they were in standard tuning; 1980s thrash bands seldom employed down-tuning. Rare examples of alternative tunings include Slayer’s ‘Hell Awaits’ (1985) and Metallica’s ‘The Thing That Should Not Be’ (1986), tuned down one and two semitones, respectively. Referencing the link between down-tuning and perceived heaviness concerning Metallica’s ‘The Thing That Should Not Be’, metal journalist Joel McIver compared Metallica’s Master of Puppets (1986) and Slayer’s Reign in Blood (1986) as follows:

It was not until their fifth album, Metallica (1991), that Metallica began consistently tuning down a semitone to increase heaviness through sonic weight.

Nevertheless, as in earlier metal productions, the bass guitar continued to stand in the shadow of the electric guitar, with the prime example being Metallica’s … And Justice for All (1988). The bass is all but inaudible on the album, and, as the band admitted themselves, this was linked to the passing of original bassist Cliff Burton.²³ The supporting role of the bass is nonetheless emblematic of metal productions, featuring a wall of guitars and dry, punchy drums at the expense of low-end thickness. Whether due to their grief or other factors, this popular record inspired subsequent bands to prioritise drums and guitars over the bass.

Metal productions in the 1980s were a playground for experimentation; bands devoted themselves to exploring the opposite extremes of meticulously produced and overly raw aesthetics. What stirred the metal community in 1991 was Metallica’s self-titled record, also known as the ‘Black Album’. Its slick, commercial and, to some, ‘overproduced’ aesthetic alienated many metal fans but nevertheless was highly influential.²⁴ Notwithstanding that the songs were less extreme – slower, simpler and more melodic – metal journalists have described Metallica as the ‘album of heaviness’²⁵ that continued to ‘push heavy metal further into new realms’ while maintaining the genetic code of heaviness.²⁶ Under the new direction of Bob Rock, former Mötley Crüe and Bon Jovi producer, Metallica explored the limits of what was possible in production. With a view to achieving production perfection, the studio time for each Metallica album significantly increased from several weeks for Ride the Lightning (1984) to nine months for the ‘Black Album’ (1991).²⁷ The latter was the first album the band recorded live with additional overdubs, which did not keep the band from meticulously crafting and tweaking the sounds and performances.

The increased popularity of other music genres like hip hop in the early 1990s prompted rock and metal productions to strengthen their bottom-end to stay competitive and continue their quest for heaviness. Hired largely as a result of Mötley Crüe’s drum sound on Dr. Feelgood (1989),²⁸ Bob Rock went to great lengths with Lars Ulrich’s drum production on Metallica (1991). Almost contrary to the dryness featured on … And Justice for All (1988), a fully three-dimensional drum sound was sought, exemplified by the kick, snare and toms being amplified through an audio system in a large room and with the resulting ambience recorded and blended with the directly captured sound.²⁹ This approach resembles the modern way of producing metal with parallel dynamic range compression and controlled reverberation added to the drum mix. According to engineer Randy Straub, parallel compression is

As with previous Mötley Crüe productions, drum samples implemented via a digital delay unit enhanced the drum sound, with Rock revealing an intention to ‘give as much weight to the drums as possible’.³¹ For maximising the kick’s bottom-end, a blanket tunnel with microphones enclosed within the tunnel was set up to capture the sub-sonic energy physically felt by the listener – a now-common technique in metal production.

Since ‘weight’ was the ultimate goal for the production, Rock convinced Metallica to tune down their guitars, an effect best heard in ‘Sad but True’. Notably, the bass has improved audibility compared to previous Metallica records, contributing to the heavy impression of the ‘Black Album’. Achieving a balance between powerful drums, solid bass and punchy guitars was a technical challenge, Rock admitted. The drums and bass needed heavy compression, but not the guitars. The solution was to compress the entire mix but bypass the guitars to maintain punch, directness and intelligibility.³² In other respects, Rock continued the excessive engineering practice Metallica had adopted. Increasing the number of guitar tracks to three, with an additional one for the stereo centre, enhanced the density of the guitar wall. To fully realise this aesthetic, Rock employed

As Rock explained, most rock productions aimed to capture the sound of a guitar played through an amplifier with one or two microphones to blend different tones and build a wall of sound.

The commercial aesthetic of Metallica (1991), with its catchy songs and slick production, was broadly criticised by fans. Bob Rock nonetheless inspired many metal producers of the 1990s and 2000s, showcasing the art form that metal music production has become; it spans technical sophistication and artistic craftsmanship, emblematising the high production quality expected in contemporary metal. Followers include producers Colin Richardson and Andy Sneap, who were instrumental in shaping the sound of extreme metal.

Extreme Metal

The transition from thrash and speed metal to other extreme subgenres, such as death metal, grindcore and black metal, was fluid. Death metal emerged in the mid to late-1980s and marked a significant increase in heaviness. Artists kept the fast pace of thrash metal but continued the formula of Venom and Slayer by featuring the double kick drum more prominently and making the ‘blast beat’ with fast snare hits a regular rhythmic element of their music. Guitars and bass were tuned down to add sonic weight, accompanied by grunting or growling vocal styles that emphasised depth in contrast to the sung vocal tenor of heavy metal or the screams and roars of thrash metal.

Death metal took a different course in the USA than in Europe. Both metal cultures had distinct production styles influenced by particular recording studios, engineers and producers who started to specialise in extreme metal. Several US studios became known for their focus on death metal production. The most well-known facility, Morrisound studio in Tampa, Florida, was centred around producer Scott Burns, attracting many bands from Florida and beyond. Musically, Morrisound is known for recording bands featuring technically demanding structures, including Death, Morbid Angel, Cannibal Corpse, Deicide, Obituary and Malevolent Creation.³⁴ Such highly technical performances are regularly described as ‘brutal’. The lack of melodic elements, seemingly chaotic and unpredictable structures, fast double kick parts, sudden tempo changes and breaks, and rhythmically pronounced guitar riffs reinforce this impression.³⁵ Guitars in Floridan death metal tended not to be tuned as low as in other death metal, which can be explained by the technical nature of playing – very fast picking, especially tremolo-picking, can be challenging with increasingly lower tunings – as well as the challenges of tuning, plus definition and intelligibility that come with it. The precise performances translated well through Scott Burns’ engineering style that placed clarity before sonic weight so that the production aesthetic can be described as ‘clean’ and ‘clear’, despite the focus on ‘brutality’. Fitting examples of early Morrisound productions that defined the aesthetic include Death’s Scream Bloody Gore (1987), Morbid Angel’s Altars of Madness (1988), Obituary’s Slowly We Rot (1989) and Cannibal Corpse’s Eaten Back to Life (1990). The high production standard at Morrisound gave death metal a professional sound, which gained international attention, making the Tampa signature widely known and gathering many followers.³⁶

Slightly later, European death metal was forming most famously in Sweden, specifically in Stockholm, with Tomas Skogsberg’s Sunlight Studios as the centre of the scene and sound. The music emerging there was influenced by the punk-inspired German speed metal of bands like Kreator, Sodom and Destruction. With its sloppy, distorted, raw and less defined sound, Swedish death metal markedly differed from US death metal.³⁷ Entombed’s album Left Hand Path, released in 1990, is generally considered to have defined the Stockholm sound.³⁸ The most characteristic element of the Stockholm signature is the guitar tone. By tuning their guitars down five semitones, Swedish bands popularised a tuning that was to become standard in extreme metal. More concerned with groove than technical complexity, the bands produced at Sunlight Studios favoured a highly distorted and muddy guitar tone over the tight sounds known from Morrisound productions, making ‘rawness’ and ‘fat heaviness’ emblematic of Swedish death metal.³⁹ The tone, reminiscent of a chainsaw,⁴⁰ was a combination of the ‘buzzsaw’ sound of the Boss HM-2 overdrive and the ‘non-buzzsaw’ sound of the Boss DS-1 pedal.⁴¹ The HM-2 with all buttons turned to the maximum is recognised as the trademark of the Stockholm sound. It produced a mid-frequency-heavy sound, in stark contrast to the scooped, mid-lacking guitar sound on Morrisound productions, for a full, dense and heavy impression that influenced the coming metal in much the same way as the US competition. Other early releases produced at Sunlight Studios include Tiamat’s Sumerian Cry (1990) and Carnage’s Dark Recollections (1990). Subsequently, a new, melodic death metal sound began to form in Gothenburg, built around Fredrik Nordström’s Studio Fredman. Although less extreme due to melodic elements, folk influences and a cleaner production style,⁴² key releases such as At the Gates’ Slaughter of the Soul (1995), Dark Tranquillity’s The Gallery (1995) and In Flames’ The Jester Race (1996) influenced many bands as well as engineers and producers by showing them how well a death metal production could work by balancing Tampa’s precision with Stockholm’s fatness.

In the evolution of heaviness, another phenomenon should not be missed: the grindcore sound of British bands like Napalm Death and Carcass. Napalm Death’s first two releases, Scum (1987) and From Enslavement to Obliteration (1988), made their mark on the international death metal scene with their extremely fast songs and blast beats, inspiring other bands to play faster.⁴³ Carcass were founded by Napalm Death runaway Bill Steer, who can be credited with tuning the guitar five semitones lower to achieve a heavier tone, a practice that would soon spread and inspire Swedish death metal guitarists like those of the bands discussed before.⁴⁴ In an interview, Carcass guitarist Mike Hickey admitted that this tuning ‘isn’t the most practical tuning in the world, but it’s probably the heaviest’, while Steer stressed the ‘crushing’ sound, but as well its challenges:

Carcass first delved into grindcore before releasing their most successful album, Heartwork (1993), which metal journalist Ian Christe described as ‘the Metallica Black Album of death metal [… and] a meticulously constructed masterpiece’.⁴⁶ Like many releases of the British extreme metal label Earache, Heartwork was produced by one of the most influential extreme metal producers of the 1990s, Colin Richardson. Following Bob Rock’s tradition, the production approach was similarly sophisticated to that of Metallica’s ‘Black Album’. Improving on established engineering approaches, Heartwork set the bar for production quality in extreme metal for years to come. The album’s engineer, Keith Andrews, shared production trivia on various online message boards, giving rare insights into the production. For the drum sound, the production team experimented with the new affordances of digital technology, converting kick and snare hits to MIDI signals in the computer. Only the kick sound was eventually reinforced by an audio sample. Their experimentation still marked the beginning of an increasing preoccupation with drum enhancement, stressing its significance in metal production.

The album’s guitar sound required considerable effort, as Steer wished for a bass-heavy yet defined tone. Inspired by the common kick drum engineering approach of blending low-end signal and high-end capture, the production team assembled two standard Marshall guitar cabinets into an oversized enclosure for the loudspeakers to increase the low-end content of the guitar signal. Later, oversized guitar cabinets from manufacturers like Mesa Boogie became popular in metal to provide a similarly deep sound. For the amplifier itself, the Peavey 5150 model was finally chosen after days of testing and combining different devices. Released shortly before the recording took place, the 5150 offered significant distortion capabilities and had a distinct character. An overdrive pedal was added to the signal chain to tighten up the oversized cabinet’s flabby response. This was achieved by setting the pedal – often an Ibanez Tube Screamer, or similar – relatively flat from the perspective of gain, tone and level, which still allowed the three stages of high-pass-filtering contained in the pedal to have the desired effect. The combination of 5150 amplifier (or newer versions of this model) and overdrive pedal affords a heavy tone with high definition at extremely low tunings and, therefore, remains a common setup of extreme metal bands even today. Metallica’s productions inspired the production team to blend the 5150 with several Marshall amplifiers for a denser texture; this technique has become an established approach in metal guitar engineering. Furthermore, instead of two guitars as typical of earlier metal, four guitar performances were recorded to enhance the wall of sound, establishing a new, enduring trend in many metal genres: quad-tracked guitars.

An alternative form of European extreme metal emerged in the late 1980s and early 1990s, most notably in Scandinavia, and became known as black metal. Ideological differences aside, black metal was clearly at odds with death metal, which professionalised production to pursue greater heaviness. Black metal artists felt that heaviness had reached its limits within the sonic confines of death metal, motivating them to go the opposite way by deliberately emphasising a lo-fi aesthetic, echoing the early releases of Venom and Bathory.⁴⁷ This sound, an alternative form of heaviness, became popular and has influenced bands to this day. Black metal’s contributions to production and mainstream notions of heaviness were perhaps modest compared to those of the bands, producers and engineers described in this chapter. Notwithstanding that black metal merges and overlaps with other forms of extreme metal, it still exists in parallel with other contemporary metal that values high-quality production.

Conclusion

Metal music has changed a great deal in its more than fifty-year history. Technological advances and the professionalisation of production have accompanied and enabled the genre’s ideological quest for ever-greater heaviness. Many of the techniques discussed have endured as standardised approaches in contemporary metal production. Production was incrementally brought to the fore, facilitating the music’s core elements and qualities, in turn increasingly informing composition and performance. This development is reflected in many ‘hyper-qualities’, such as hyper-perfect performances and hyper-real sound staging. Digital audio workstations with ever more powerful editing and quantisation capabilities allowed productions to become faster, more technical and yet more precise. Hyper-compression made releases louder, partly contributing to the so-called ‘loudness war’. Partly enabled by extended-range guitars with seven, eight or nine strings, advanced amplification technology and extreme audio processing tools and techniques, tunings were increasingly lowered, giving rise to entirely new metal subgenres like djent. The consequence of this development was that the commonplace practice in the 1980s – the live recording of basic tracks – practically vanished. Nowadays, drums are often recorded last and quantised to a grid or entirely replaced by programmed performances, and likewise, bass parts are sometimes programmed. Further complicated by decreasing budgets, the quest for greater heaviness demands performance precision and extremity beyond what is humanly possible.

This chapter examines the lived experiences of UK-based record producers with notable credits in the metal genre:

• Romesh Dodangoda (Cardiff, UK): Bring Me the Horizon/Motörhead/Sylosis

• Mike Exeter (Birmingham, UK): Black Sabbath/Judas Priest/Cradle of Filth

• Tom Allom (London, UK): Black Sabbath/Judas Priest/Def Leppard

• Martyn Ford (Newport, UK): Skindred/Slipknot/Bullet for My Valentine

• Russ Russell (Northampton, UK): Dimmu Borgir/Napalm Death/SikTh

• Dave Chang (Reading, UK): Electric Wizard/Earthtone9/Orange Goblin

• Oz Craggs (Folkestone, UK): Feed The Rhino/Polar/Dead Harts

Interviews were conducted in 2014 to explore technology as a lens through which we can ask how knowledge is known rather than what is known. Importantly, the interviews prioritised asking participants how technology has influenced the experience of making recorded metal music.¹ The main impetus was to develop a deeper understanding of technological influence and the experience of using technology as part of their creative process. The intention was not to construct a production methodology for metal music but to use these lived experiences to explore the tensions caused by expectations and anticipations of the use of technology in the recording studio. The producers were asked to make sense of the music they work with and how it is defined by the objects (technology) that surround it, as well as their relationships with artists and recording studio occupants and the musical and metaphorical semantics of record production.

For these communities, production is understood to be an everyday activity.² This activity is situated within a life-world (recording studio) and enabled by a contextual influence (technology). Jonathan Smith et al. suggest that to be phenomenological, we must ‘attend to the taken-for-granted experience of [an activity]’.³ By asking record producers to consider the way in which they conduct their everyday activities, the small decisions that they may take for granted, or the techniques that they rarely think twice about, we can start building a more holistic view of the impact of technology on record production and the development of the sound of recorded metal.

The Recording Studio

The recording studio should be understood as a space in which music and unique technologies meet. It is a world that provides the opportunity to create systems and technologies from the activity that is contained within it. The space itself is unashamedly technological, transforming sound waves produced inside it, designed to create new artificial waveforms that could not be formed elsewhere.⁴ Music technology has the potential to act neutrally and purely facilitate production, but it can also be seen to no longer be neutral through repeated use and developed practices, collating a number of social-cultural meanings. The recording studio is not passive in the act of making music; it is a world that encourages unique cultural (musical) phenomena.

In Nature of Technology,⁵ W. Brian Arthur defines technology as singular, plural and collective. Singular technology ‘originates as a new concept’⁶ and internalises development. Plural technology develops its constituent parts and practices (installing new parts into a computer, for example) and becomes plural by building around phenomena. In a collective sense, technology ‘encompasses the entire collection of devices and engineering practices available to a culture’,⁷ uses natural phenomena and develops through multiple technologies working together. Phenomena here are the acoustic variables (sounds) that music production technology exploits. The act of exploitation validates objects as technological, and the recording studio is a technological space because it affords creativity. The recording studio therefore demonstrates technological plurality: multiple groups of technologies and people that work together to capture acoustic energy and transform it into electrical energy, and back again. It affords the capture of a performance; it is a tool affording the documentation of cultural phenomena. It is a space for communities to interact with technological objects that tend to only exist in those spaces, influenced by socio-cultural applications of technology.

Over the last century, the primary act of performing music in the recording studio has changed dramatically in response to various technological and socio-cultural practices.⁸ As these practices have evolved, production technology has become an integral part of all levels of music-making and is readily available to all musicians, professional or amateur. Personal computing affords musicians the ability to document their creativity away from recording studios outside of the temples of sound that have housed music production for the majority of the twentieth century.⁹ Performers, songwriters and instrumentalists cross the threshold into music production with relative ease and understand how to recreate unique sonic aesthetics¹⁰ whilst also employing the technology of studio production live on stage and in rehearsal rooms. Artists now expect more from recording studios and the people and technology that occupy them, forcing movement away from capturing whole performances to constructing them.

Because of these shifts, record producers have a very different role to play in the production of recorded music. They are not only facilitators of technical processes but creative overseers of unique projects that can encompass music-making over remote distances, time zones, multiple personnel and multiple socio-cultural influences. The relationship these producers have with the process has been dramatically changed by technology and has begun to normalise new approaches to making music in the studio environment. For example, contemporary recorded metal normalises performance-enhancing processes as a form of technological plurality rather than the singular documentation of performances.¹¹ It is the intersection of practice and the expectations of both technology and communities surrounding metal music that warrants a phenomenological analysis of metal music production.

Technological Ideologies

Significant literature surrounding the complex nature of contemporary metal recordings details how recordings are constructed from a technical perspective,¹² in-depth examinations of geographical and stylistic traits within productions,¹³ and the analysis of discrete trends in the use of specific technology.¹⁴ The producers who make up the sample of this chapter identified with all of the themes in the current literature but also a number of key descriptors that encapsulate the audible phenomena of metal music: impact; energy; precision; extremity. Historically, these audible phenomena are highly important to our understanding of the genre’s technological narrative. Proto-metal artists drew inspiration from the sounds of the British blues scene in the 1960s and artists like Little Richard, Chuck Berry and The Kinks, incorporating cover versions into their live performances.¹⁵ The ability to record isolated instruments on multitrack tape changed the way in which metal artists thought about the sonic qualities of the artists they drew inspiration from, including the subtleties and nuances (or indeed the lack of dynamic subtlety) in drum performances, the ability to drive valve guitar amplifiers into high levels of harmonic saturation, and the movement away from direct injection recording.¹⁶ Metal’s audible phenomena were created as performative interpretations collided with new technological possibilities.

These audible phenomena tend to be determined by a dominant commercial ideology¹⁷ that has the potential to influence the choices made by record producers, who are expected to create the sound the artist (and often audience) envisions, as well as achieve audible intelligibility within the final production.¹⁸ This ideology is expressed in a number of ways but often returns to the way technology can (or does) act deterministically during the production process.¹⁹ Artists seem to embrace this determinism and accept it as a primary feature of the creative process. One of the interviewed professionals, Martyn Ford, suggested this is a unique problem with contemporary metal music as it exists in the recorded format: ‘The most overlooked thing in metal or rock is the song … By having a great production, you can almost get away with existing as a band.’ This is not just a technological issue. At the heart of what Ford claims is a suggestion that metal music is made in ways that disassociate the musicality of the work from the audible phenomena; if a record sounds good, it must be good. The prevalence of online resources²⁰ that are dedicated to metal production tips and guides, as well as the close links that metal musicians have with the contemporary studio environment, has changed the role of the producer in the minds of the artist and audience, and indeed the importance of production in the making of a record. Technology has allowed musicians to become producers in their own right, as they can now visualise more of the process of making records, changing the way in which they are consumed. If Ford is right in his assumption, then the same could be said for how audiences are now experiencing recordings. Are they listening to the song or the sound of the song? The other participants raised this same issue in slightly different ways, suggesting that technology has influenced the way metal records are made:

The genre’s sound has changed over time, no matter the similarities in musical or stylistic approaches, but it seems that the producers who are making it are at odds with the use of technology. The technological advances give the perception that using technology is critical in a genre-specific capacity and affords the explicit audible phenomena of recorded metal in the twenty-first century. The producers themselves seem to want to use it as little as possible, or at least in the least noticeable ways. However, they know that audiences and artists now expect certain things from recordings. Ford suggests that one of those things is precision, particularly in relation to timing and quantised performances²¹:

The likening to machine only further implies the influence of technology on the audible and semantic phenomena surrounding metal production. The technological expectations that align with contemporary audible phenomena, namely: bass guitar distortion, brightness and heaviness of guitar timbres, and kick-drum sampling²² start to support a view that production methods have become homogenised.²³ Oz Craggs draws on the idea that this homogeneity is explicitly linked to the idea of commercial ideologies:

Heaviness becomes a conglomerate of these expectations and homogenous practices. As the outcome of these contemporary audible phenomena, it is linked intrinsically to the development of genre-specific production aesthetics that become more acute over time, and heaviness becomes a signifier of quality. As with Ford’s assumption, if a record sounds heavier (i.e., it has more of the audible phenomena audiences expect), it is a better record. This is demonstrated in an early interview with Black Sabbath singer Ozzy Osbourne prior to the release of 1971’s Master of Reality:

This technological ideology demonstrates that recorded metal music embodies constant performative and sonic development through evermore overt showcases of energy, extremity, impact, precision and speed. These performative qualities have been prompted by technology that affords the ability to deal with, and create, heaviness more efficiently.

Forging the Sound of Metal

To understand how these technologically informed ideologies are established, it is important to trace the history of the technological decisions being made and the resulting audible phenomena, which began arguably in 1969 at Regent Sounds Studio on Denmark Street in London, UK. Now the location of a guitar shop, the small basement recording studio was the site of a short recording session for a band that needed to record demos after attracting record label interest. That band returned later that year to record their first full-length album, which was released on 13 February 1970. The band was Black Sabbath, and the recording engineer was Tom Allom. Allom was interviewed to explore his role as recording engineer on the first three Black Sabbath records under producer Roger Bain and as producer for artists such as Judas Priest and Def Leppard. Black Sabbath (1970) was mostly recorded live over the course of a single day using Regent Sounds’ limited technological setup:

Whilst the simplicity of this type of setup is to be expected of the time, it emphasises that the genre’s sonic foundations were not dissimilar to any other recording made in the late 1960s and early 1970s; there was nothing remarkable about the technology used. Artists would record live, together in one room with some acoustic separation. These sessions would have captured multiple versions of full takes of songs, with the producer deciding which was the best performance. For Allom, using this technology was a test of his ability to work within its limitations.²⁵ He highlighted that ‘the final mixes of the first Sabbath album … were mixing a fifth-generation 4-track’. It meant that additional parts would be layered on top of the selected performance, thus creating some of the first signs of the audible phenomena we recognise now, primarily double-tracked rhythm guitar parts.

This shift begins to make recording multiple passes part of the production methodology of metal music. It makes the process non-linear, and non-linear production practices are increasingly evident in the way contemporary producers work. Some of the participants highlighted that the heaviness that audiences now expect is created when employing these non-linear or fragmented production practices:

Craggs suggests that it just is not acceptable to make a record without intervention, whilst Ford suggests that because of the acceptance of non-linear production practices, some artists have adopted that into their writing and rehearsal approach: ‘A lot of bands have never even played the song together. A lot of metal bands tend to do it that way these days’. This could be seen as removing a sense of creativity. For Allom, when working on some of the archetypal metal recordings, working in creative ways to fulfil artistic intention and swerving technical restrictions created new genre-specific audible phenomena: overdriven double-tracked guitar rhythms; the prominent bass guitar; drums that fill the extremes of the stereo space. Technological development that afforded new sounds and approaches embedded technology at the heart of metal music production. The earliest examples of recordings to exhibit these phenomena align with some of the earliest widespread availability of multitrack technology (four or eight tracks) in smaller recording studios.²⁶ Most interesting is that early metal artists were not using the technology in the more experimental ways that their contemporaries were outside of the genre.²⁷ There is little to suggest, by critically listening to early records by Black Sabbath or Coven, that the decisions made were meant to imitate the progressive sounds heard on records by The Beatles or Pink Floyd. Allom explained the practical impact of increased track count at Regent Sounds:

Whilst limited compared with the affordances of contemporary recording technology, Allom was clearly excited by the possibilities the extra tape machine afforded.²⁸ Ford affirms the ways in which technological affordances present new opportunities for producers:

As an example of the space created and the resulting impact that each element of the mix has, ‘Hand of Doom’ from Black Sabbath’s Paranoid (1970) features wide-panned, double-tracked overdriven rhythm guitar parts throughout. Not only does this create a dense and powerful guitar sound, but it allows the individual drum elements space to punctuate the mix (03:40–04:00). Without the ability to record individual elements of the instruments in detail, this sound would not have been created easily in the analogue domain. Allom’s ability to control spatial imaging and overdub guitar riffs begins to set up a series of expectations that inform the construction – rather than the live capture – of contemporary metal recordings, putting ‘the emphasis on carefully adding and shaping sounds is fundamental to the record’s aesthetic quality’.²⁹ One of the drivers of recorded metal’s unique production practices can also be its social consumption. It is driven by the live experience and the sound of a band in a venue, whether on stage or in the audience. Artists typically rehearse in practice rooms at loud volumes preparing for the sound they will have on stage, and recordings are often produced to sound ‘mimetic of that form of large-scale space’.³⁰ The ability to orchestrate the position of the band in a recording with a sense of size and scale is key to creating the audible power of metal productions.

Fragmented Productions

These formative metal recordings not only allowed artists and producers to establish the audible phenomena of metal music, but they began to dictate some of the performative qualities that proliferate contemporary recordings. Allom further emphasises ‘tightness’ as a musical aesthetic that was key to the sounds achieved at Regent Sounds:

This points directly to the established production methodologies that have been developed for contemporary metal music. Performances that are virtuosic and create impact through precise musical synchronicity are integral to production of intelligible and impactful metal music.³¹ These types of performances present one of the most challenging aspects of the genre’s production and the element that contemporary technology often aims to create simple solutions for. These performances often rely on technology to be able to isolate minute detail and correct dynamic or temporal issues. The most isolated these edits or alterations become, the more fragmented and non-linear the production becomes. Fragmentation, particularly linked to multitrack technology, moves production further away from live performance and closer to total isolation and construction of individual instrumental parts that may have never even been played in the same acoustic space.³² Typically, metal music exists decreasingly as a live phenomenon in the recording studio because of decreasing recording budgets and the increasing cost to maintain physical recording studios. The level of control now afforded by multitrack technology has promoted a movement away from using acoustic space to create the vast majority of contemporary metal recordings. Ford highlights this, drawing on his experience of playing with metal dub artist Skindred:

Ford laments that the desire to make records this way has dissipated. He recognises that it will typically come down to cost and the availability of spaces that would accommodate this type of production style. There is much written about the changing finances of the music industry, and it would be safe to assume that bands in the genre are not going to be commanding the types of budgets that would afford them the use of studios to make records in these ways. There are, of course, exceptions, but on the whole, the experience of the producers interviewed is fairly modest when discussing budgetary influences on the scope of records they make:

Mark Mynett’s work on the production of contemporary metal music³³ supports the views expressed by the participants, recognising that record producers and engineers are often charged with creating an experience rather than capturing a performance that is the experience itself. It assumes that producers and artists alike are pre-empting the use of particular technological processes. The monumental shift away from recording performances of pieces of music has distinct advantages (e.g., performative inconsistencies are reduced, and records are made at significantly reduced cost) and disadvantages (e.g., homogenised production of dynamics and rigidity of mechanically edited performances).

Conclusion

The development of music technology has led to the dominant technological ideology that has been embraced by the participants, some more willingly than others, as part of the service they provide to artists. Tension between how technology is used and the perception of its use when producing metal music strengthens the case that contemporary music production has become increasingly fragmented and now constructs musical performances that adhere to idealistic representations. For metal music, these representations align with qualities such as extremity and precision, impact and energy. The dilemma that metal producers face is how they comply with the technologically influenced ideologies and how they assimilate them into their own practice. Recorded metal is now a separate entity from the live instance of the same music, as it is often influenced by a number of expectations and pressures. The interviewees highlighted how the uses of technology and a changing record industry have led to the establishment of accepted ideals for metal production, ideals that producers often feel obliged to provide.³⁴ Russ Russell surmised that technological development could only influence music to a finite point before it causes a problem:

The idea here is that perhaps technology has influenced the production of metal music to a pinnacle point, hence why homogenous production practices have been assimilated without resistance. This then presents an ethical dilemma that all producers face: how much do they let technology influence their approach and the recordings they make? It could be the case that music technology has advanced to a point that it removes the creative choices that informed many of the early, archetypal recordings made by the likes of Allom. It could also be that technology has restricted this creativity so that metal records cannot be made independently from the canon of contemporary metal productions. It seems appropriate to return to Arthur’s Nature of Technology. Arthur suggests that bodies of technology ‘give rise to the characteristic industries of an era’.³⁵ Metal music production has been defined by technological development, and the experience of the participants affirms that contemporary metal music production could indeed be described as a characteristic industry, an industry of accepted ideals afforded by creative technological exploration that has been assimilated into the practice of contemporary record producers. This has resulted in the prominence of technologically reinforced performance practices and an increasing dependency on technology to produce metal music.

A couple of decades ago, it would have been regarded as non-academic to pursue research, which involved not only being closely associated with a given field but also doing the activities within that field as a member of the studied community. The scholar was expected to be a respectful outsider and ensure that their presence did not alter the phenomenon they observed. It would not have been considered ethnography if the investigator acknowledged that their presence, decisions and personage were to be branded upon the outcome. The assumption was that the author should act like a camera and not assume the role of a film director. Their duty was to observe anything and everything in the form of thick description, audio-visual documentation or analysis, using one or a selection of the habitual tools of social sciences. In one of the core textbooks of ethnomusicology, Helen Myers admits that ‘the act of anthropological observation is obtrusive, inevitably altering the behaviour of the observed’.¹

Practice-led research, the method used in this chapter, proclaims to do almost the opposite. This method, at times, formulated with slightly different wordings, such as practice-based research, practice as research or artistic research, lends itself useful when researching any discipline that involves creativity or artistic expression. In her research, Lyle Skains puts forth that pursuing art as research does not only offer insights into art and the practice of art as it occurs, but can shed new and unexpected light on a range of topics, including cognition, discourse, psychology, history, culture and sociology.² In this sense, practice-led research is ‘a targeted combination of autoethnomethodology, reflection applied to cognitive composition and creativity models, and post-textual media-specific analysis of the creative artefacts’ akin to similar methods used for medicine and engineering’.³ Accordingly, the creative process is both artistic and analytical: practice-led research is thus reminiscent of a hard-sciences researcher working in their laboratory. However, within humanities, perhaps due to the quest of presenting the research outcomes in a more ‘scientific’ sense and having as many shared attributes with hard sciences as possible, the use of practice-led research is relatively new.

This chapter is constructed around the mainly diachronic story of the Turkish metal band Listana. Metanarrative, used in the title, is a term developed by Jean Francois Lyotard to denote a grand narrative that seeks to connect separate events in a timeline to plausibly explain phenomena, such as social contexts and experiences.⁴ A metanarrative must be grounded in the context of universal truth, similar to a causal chain, explaining and organising knowledge. In the context of the present chapter, metanarrative describes a ‘self-directed form of ethnomethodology’⁵ encompassing field notes, audio-visual material, formal and informal input of the involved parties and the musical products created to constitute the basis for analysing the creative process. The documentation is thus intertwined with the process itself, enabling a deep, subjective record of the entire procedure. Scholars who map out practice-led research as a method seem to agree upon not considering subjectivity as a problem. In this chapter, the intention is not to artificially elevate the band experience to the theory level by abstracting it or forcing generalisations. Instead, it gives a first-person account of a female-fronted metal band in Turkey.

Listana’s Formative Period

Listana was founded in 2011 as a five-piece female-fronted metal band in Istanbul, Turkey, by amateur musicians who sought to develop their musical skills through exact covers. The initial aim was to perform known bands’ music as close to the original as possible before turning to compose original songs. Despite being marginalised as a female-fronted band in the male-dominated metal music industry, Listana managed to survive the emerging phase, achieving the level of supporting international metal artists at domestic festivals and abroad in a relatively short time. Experiencing both setbacks and support, like many new metal bands, it became part of the vibrant Turkish metal scene Pierre Hecker describes.⁶

Initially, Listana performed the symphonic metal subgenre, common for female-fronted bands. Later, the band revised its playlist to form and occupy a niche of its own by turning to progressive metal, a technically demanding subgenre that is not very common or in demand in Turkey. Refraining from stereotypical themes of metal music, such as anger, violence, masculinity and promiscuousness, inevitably branded Listana also as an alternative metal band. Embracing being ‘progressive’, the band went on to create original music featuring daring harmonic effects, novel textures and odd time signatures. Despite drawbacks, such as frequent lineup changes, lack of experience in terms of producing and promoting original music, mediocre equipment and meagre stage experience, it was always possible to find gig opportunities and play to full venues.

Conflicts from Musical Socialisation

Having interviewed many metal performers with global careers, such as Zakk Wylde and Jordan Rudess, as well as some of the most prominent Turkish protagonists of the metal scene like Murat Ilkan during my research, I feel entitled to generalise that, unless they happened to grow up in a particularly musical environment (musicking parents, for example), most metal musicians pick up their instruments around the time they are in junior high school and start their musical career in their mid-teens. On the contrary, my exposure to metal music came at a later point in my life, when I was drawn to symphonic metal as a listener through its well-documented connection to classical music. I did not have any interest in performing metal until I received the offer to join Listana as a keyboardist and backing vocalist.

Unlike the other five members of Listana, I had no experience in amplified music at all, so I was much less skilled in the studio than my new colleagues. As a trained pianist and composer according to the Western Conservatory system, I never worked with musicians from diverse backgrounds. My musical experience consisted of classical music performances: solo piano, chamber music, accompaniment, acapella singing. Assuming that my newfound colleagues would have had at least some kind of musical education, I expected procedures I was familiar with through these settings. However, unexpectedly for me, adaptation and advancement became a difficult issue for everyone. Unfamiliar terms such as ‘riff’, ‘groove’ or ‘guitar tone’ seemed to belong to the genre we strove to perform, but I did not have any contextual grasp on them, my colleagues could not verbally define these to my satisfaction, and internet sources were in disagreement on their exact meaning. I was unable to communicate my knowledge, intentions or opinions through the musical jargon I was proficient with. Worst of all, I had limited skill and understanding of my new instrument: I had no notion at all of sound design or keyboard programming. Consequently, I was not able to use my entry-level Roland synthesiser to much effect, even though my keyboard technique was much more advanced than the parts I was required to play.

All in all, I found out that the expectations and performance standards of metal music differed from classical music. For instance, meticulousness and clarity were drowned in the noise during studio sessions at times, but colleagues did not seem to mind as long as the flow was not affected. I worked closely with the band’s semi-professional guitarist, who picked up the instrument at thirteen but never had any tutorage. Since both of us were required to play antiphonal, parallel or even unison solos, I constantly attempted to teach him music theory, notation and the ‘correct’ jargon, such as not calling lower strings ‘upper’ strings because they are vertically at a higher position. Yet, he did not show any significant interest, being content and successful with his mnemonatic and tactile musicianship; some issues of musical communication were thus forever left unresolved.

Reflections

When the problems described earlier affected my musical satisfaction, I felt it necessary to reflect on the reasons and began to analyse the experience. In Philip Bohlman’s words: ‘Thinking – or even rethinking – music … is at the base an attempt to claim and control music as one’s own.’⁷ Thinking along the lines, ‘I have the longest and most comprehensive musical training, so I should have the authority on musical decisions’ or ‘it is my bandmates’ shortcoming if they do not understand when I speak about third-degree modulations or thematic transformation’, did not solve any problems. It was a revelation to discover that performing metal, thus learning another genre’s performance practices, was a means to indulge in the pleasures of escapism for me. I was venturing into the realm of the musical ‘Other’,⁸ behaving like many classically trained musicians, enjoying the popular music experience but without adopting it or declaring it an integral part of my musical identity out of unacknowledged subconscious contempt. Even though I was devoting ample time and resources to learning conventions and performance practices, I was still the superior, justified ‘Self’, who was presumably able to direct the musical experience in the manner I was taught during my studies. In short, I failed to understand ‘one of the pillars of rock ideology: opposition to authority and discipline, and, by extension for musicians, opposition to a structured approach to the learning of music’.⁹

I needed to break with this attitude and accept that I had deficiencies and still things to learn in order to progress. For one, I discovered that I was completely insensitive to what popular musicians refer to as ‘sound’, and I only perceived the music through its quantitative parameters like pitch, rhythm or harmony. My approach was, in fact, very Adornian because I was seeking music’s meaning and significance exclusively in its formal characteristics, notated or otherwise prescriptive, instead of the elusive and mysterious ‘vibe’ my bandmates sought. They seemed to respect my knowledge but did not evaluate the rehearsal techniques or aims I offered as useful or efficient: I was simply not metalhead enough for guiding a metal band, in their opinion. From their rebellious stance, the rigour and discipline of my classical training rendered me stiff.

As my experience grew, I came to understand that it is actually those elements between the notes that are making the music ‘metal’. To a mind, which is programmed to use prescriptive Western notation to produce music, it is hard to accept the reversal of this idea. In the limited sense, notation gets to be used in metal music; it is an inadequate, descriptive tool. The idiomatic, instinctive ‘licks’ of the guitars, unwritten rules of composing bass and drums parts, timbral quality and treatment of scalar or modal material outside the conventional rules governing classical music are habitually captured by recordings. The composer and performer often being the same individual reinforces these characteristic properties to an extent few instrumentalists and composers of the Western musical canon, such as Chopin, ever achieve. Yet, again resulting from the seeming inadequacy and incompatibility of notation, if one is not skilled in treating a recording as a learning source, even an accurate transcription would not guarantee an authentic performance.

Becoming a Metal Musician

No study on metal music composition describes it as a standard procedure. Besides participant observation, I was able to gain some insight into how metal musicians and bands create music through interviews with professional metal musicians. It is unproven but potentially true that the stereotypical metal musician uses the ear more than the eye to create music. I eventually encountered a metal songwriter, who exclusively composes using Western staff notation and distributes this material among his band members, but new, original music arises from ‘jamming’ together for most bands. Michele Biasutti’s work depicts a similar process, the compositional procedures of an Italian progressive rock band.¹⁰ Biasutti analyses videotaped data to categorise his findings into five themes: context definition, experimenting, constructing, playing and evaluating. He uses an adaptation of the comparative ethnographic method to calculate how much time is spent on which respective compositional activity.

Returning to the microcosm of my own band, I can state that no Listana song was composed by the same band members in the same manner and employing the same procedure. Each song unfolded differently and took different amounts of time to write. Of the released numbers, the easiest to compose, ‘Elveda’ (2013), took only a few days, whereas some numbers, such as ‘Persona non Grata’ (2014), took a very long time, spanning a few months and undergoing drastic changes. As an active participant of the compositional sessions, I did not have the chance to employ similar data collection or analysis means as Biasutti did, who warns ‘when actions are driven by the researcher, the participants are not free to express all possible behaviors’.¹¹ I have observed that it took Listana about a year to bring a piece from scratch to the recording phase, but this time requirement varies considerably between metal musicians and bands.

Once a band’s endeavours reach the recording phase, its existence is confirmed. A ‘demo recording’ is an initial, usually technically flawed, sound or video recording that establishes the band’s existence: the first outlet of a band to its potential audience. Without a demo, a venue would not let a band perform, as its musical inadequacy could cause them to lose their customers and even damage their inventory of sound or stage equipment. Therefore, as soon as a garage band decrees itself ready, its members attempt to record their output. Recording together in such a manner is called a ‘rush’ session and is seldom a flawless, immaculate affair. The recorded song could be a cover, especially if the band intended to perform at a venue or plan to attract a social media audience that would place them in the metal oeuvre due to their similarity to existing bands. Recording is a challenge for any band, be it in the relatively comfortable environment of a home studio or a fully equipped professional studio, where time and expertise must be paid for. Usually, less proficient musicians can only focus on their own instruments when jamming or gigging, without paying much attention to what the others are doing or how the ensemble sounds together; recording is therefore essential as a self-evaluation tool as well.

During Listana’s existence, there have been innumerable recording sessions, some fruitful, others not. At the onset of the band, none of the members had enough proficiency with studio technologies or even minimum equipment to record at home, so even the earliest demo recordings had to be outsourced. From home studios with poor equipment to high-end studios where the hourly rent would be hundreds of liras, Listana explored many music production settings, gaining valuable insights. As the band members had day jobs, there were the financial means to hire professional studio staff and use proper equipment, but this did not ensure that a decent product emerged or that the resulting recording proved usable. Often, older recordings were discarded in favour of a newer recording that was meant to fix the flaws of the previous one. Another reason Listana’s earlier recordings had to be discarded is that the band had to change vocalists four times in its initial two and a half years. If the replaced member had been an instrumentalist, the recording could have still been used with the permission of the former and current member, but there is no way to redeem or alter a finished recording with vocals short of re-recording. To avoid such issues in the future and to align the musical mastermind and the ‘front’ of the band, I was eventually ‘promoted’ by my fellow band members to be the band’s lead singer as well as the keyboardist. For some time, to acquire live performances, we recruited a second keyboardist while I was using a keytar on the front stage.

For local metal artists, being on the stage of large-scale events is a rare occurrence. Metal artists, who must invest much time and capital to acquire their skills, equipment and networking, seldom make any money from gigging in Turkey. Metal clubs in Turkey usually have their selection of bands-in-residence that play covers of their regular customers’ favourite music. These bands are formed by professional musicians, expected to play every week on their designated day, for a previously agreed fee per performance, split among band members, independent of the revenue of that particular day. Very few of these house bands have their own compositions or follow the same path as original bands that seek to establish themselves as metal artists on the domestic and international music market. Therefore, metal clubs that have live stages hardly ever hire new bands with an original discography. Since the supply is greater than the demand, most metal musicians must call their performances ‘concerts with free entrance’, where the expected outcome is exposure, beer and fun, rather than a professional opportunity for which they would receive some payment in money.

During the time it was actively performing, Listana was a conspicuous band because of the female lead and technically demanding music it sought to perform, which was rarely, if ever, attempted by cover bands. In the first half of the 2010s, the band gigged very often: besides a lively club scene, there were also open-air metal festivals in Turkey in that period. The average live club performance lasted around an hour, but there were also shorter appearances, such as at university festivals, which typically had a stage time of half an hour, including changeover and sound check. For a few months, the band even performed weekly in DoRock Taksim, the largest live metal club in Turkey, as a paid house band that performs a two-hour program – a very competitive gig. Listana even made it to the big stage to support international bands, such as Orphaned Land, Dark Tranquillity, Sonata Arctica and Theatres des Vampires, among others. A major achievement was to perform abroad in Ukraine in the summer of 2013, supporting Overkill, Artillery and Dying Fetus. For an emerging band, an invitation to a festival meant that they would have to pay their travel and accommodation expenses themselves; such event organisations only have the budget to fully reimburse headliners and co-headliners. There is even a concept called ‘buy-in’, which means that a new band paying a certain sum might get a slot to perform at a festival or open for a more established band on tour. Major European festivals claim to shun this practice; I have witnessed the organisers of Hellfest state that a non-proficient band is not allowed on any of the festival’s nine stages, and no sum of money can change that.

Performing Live

Most studies detailing the experience of live metal concerts are from the viewpoint of a spectator present among the audience or backstage. When considered from the performer’s perspective onstage, there is next to no research available. I only encountered one other metal music scholar with a research design similar to my own: Jasmine Shadrack, who reports her experiences in black metal.¹² Acquiring the expertise to perform any music for an audience is a difficult task and more demanding with some music genres than others. For metal, the rules are clear: a performer must move and look representative enough on stage to communicate with and animate their audience. Inevitably, the focus is divided between performing well enough and interacting with the audience, verbally and nonverbally. Shadrack summarises: ‘Make no mistake, if you are in a metal band, remaining static whilst you perform negates the performance itself. The physicality, endurance and focus required to ensure precise playing whilst head-banging for example, takes practice.’¹³ No matter how much one practises on their own or with the band in the studio environment, genuine stage familiarity can only be acquired on stage in front of a real audience.

It was fortunate that I came to the front stage after being on the keyboards for two and a half years, which taught me how to connect with the audience to some extent. Learning to sing properly is no different from learning a new instrument, and it took me a long time to gain a semblance of confidence again. The audience walking in and out of the venue during performances, approaching to listen or going out for a smoke or chat, was not much of a concern for me before, but after I assumed the role of the vocalist, it often made me feel insecure. I kept asking myself if they were fleeing from my poor performance. The after-show adulations that I became used to in those first years of my metal musicianship were now replaced with some audience members avoiding eye contact with me or even ignoring me altogether, sometimes extending into anonymous derogatory comments on social media after shows. There would always be people charmed by my unusual voice, but I keep having detesters to this day.

A general procedure of a Listana concert was to arrive with equipment at the venue, sometimes several hours before the performance if we were the opening band, set up the rig, perform, disassemble our own gear and abandon the stage for a changeover. Although the stage mood resulted in extraordinary iconography in the form of photos and videos, there was not a single concert where everyone claimed to have been able to hear themselves and everyone else sufficiently and clearly, and where everything went smoothly. Performing meant all kinds of mishaps happening; very rarely everyone in the band would be satisfied with the outcome and leave the stage exhausted but satisfied.

Regardless of the genre they play, musicians have less time to devote to practise when they have day jobs. Lack of mental discipline, physical stamina or practice time compromises performing a distinctly virtuosic subgenre of metal through long playlists. During Listana performances, as with many other metal bands, we had instances of drummers rushing tempos that caused unclear passages or wrong entries in the case of instrumentalists. Irrespective of how much individual practice went into them, technically challenging parts sometimes became muddy with stage excitement.

When there are shortcomings among the internal factors that constitute the band’s sound, ‘outside’ factors gain visibility beyond control, putting the outcome at risk. A band needs at least one person with an appropriately trained ear, who must be proficient in determining if the guitar and keyboard are properly compressed to not mask each other in the sonic spectrum, but this is often not the case, Listana being no exception. Without sufficient aural awareness, there is simply no guarantee that even the most advanced equipment would deliver the desired results. Let alone hiring a professionally trained live sound engineer, few venues take on the expense of dedicated staff operating the audio console for underground metal bands performing gigs. Therefore, the musical outcome is seldom the intended balance in terms of the mix.

Status and Gender Experiences

For Auguste Comte, music is the most social of all arts.¹⁴ In the case of metal music, since it has a close and well-defined community, this statement rings even more true. Most metalheads I have made acquaintances with during my fieldwork decided to interact with me after learning about my band and performer status. My status as a researcher did not win them over, especially if they already had some dissatisfaction about their education or professional life. Some informants I attempted to interact with found it offensive that I was researching something like metal music, which is sacred to them, thus devaluing it. Fortunately, most of my informants made clear that I deserved their input since I was a metal musician as well as a researcher. In their eyes, my ‘fakeness’ and ‘being a poser’ was redeemed by the fact that I was performing metal.

As a musician and researcher, I disregarded the gender inequality in metal music as much as possible. There are two ‘allowed’ dress codes for a female metal figure: either to assume an utterly gender-neutral or even masculine dress code, or a hyperfeminine dress code.¹⁵ According to the subgenre performed, variations of these two basic templates are possible. I was not comfortable with masculine or gender-neutral attire, nor did I wish to draw attention to my sexuality, so I always targeted a middle ground of femininity in my stage costumes. Neither Listana members nor other metal musicians we performed with treated me differently for being a woman: what mattered was music, not privileged chivalric treatment. The audience was another issue, though: there was no way to avoid the male gaze, which ranged from fervent admiration to outright misogyny. Although I refused to acknowledge it, I represented the ‘Other’ in some audience members’ eyes: an anomaly, tolerated at best.

The initial two-year phase when I was solely the keyboardist, working hard on my live sets and performance skills, spared me from the negative end of this spectrum, but assuming the lead with a less-than-ready voice foregrounded my gender in the worst possible way. In Shadrack’s words, I was bold enough to occupy a male space in an overtly male genre.¹⁶ Considering that Listana performed progressive metal songs and most of these pieces are written for male voices, the initial reaction to my vocal performance was anything but favourable. We had performed some of those same numbers with our previous vocalists, but they were all more experienced singers than me, so the sexism they faced had a different nuance from what they told of their experiences. For me, the accusation was a gendered one: I was a poor vocalist who thought I could make up for my lack of talent by being an attractive woman and ‘enthraling’ my band members.

Interestingly, the strongest discouragement came from other women, who sometimes were not even musicians themselves or had projects in earlier stages than Listana. My interpretation is that the space for women is quite narrow in metal music performance, and competition is inevitable. From these female detesters’ perspective, it is utterly unfair that I get to ‘reign’ on the stage, performing with more than adequate musicians and commanding their respect despite my obvious shortcomings. The men were another matter: for some, there is always the attraction, and the flaws in my performance thus serve as a pretext to approach me. For others, it is sacrilege that a woman, who happens to be an inexperienced singer, is offending their musical senses by daring to perform progressive metal numbers. Undeniably, I had much encouragement from within the band, partially stemming from the members’ exasperation about the conflicts and problems we experienced with the four vocalists we tried. It is a cause of remorse for me that they had to endure the blows from the audience together with me; the process has been an eye-opener and led every band member to question musicianship and social pressure associated with metal.

Releasing an Album

The fertile environment and vibrancy of the Turkish metal scene meant that Listana could experience the thrill and driving motivation of an emerging band, similar to the accounts of comparable international bands. To consolidate this rising trend, an album was needed to be released: the presence of a solid recording of original music meant that Listana would be perceived as having enough identity and skill for large-scale events. However, such a band whose output was quite far from the Turkish mainstream had next to no chance of finding a local label willing to make a commitment in terms of promotion and digital distribution. Without the necessary know-how and connections to seek an international label, the decision was made to digitally release the Listana album Unveiled in 2013 as an indie band. Such an enterprise would have been immensely difficult without intermediaries just a decade ago, but online distribution companies such as CD Baby are now available to provide an artist’s track with the UPC/EAN code, which is a validation for use on the internet. It is thus possible to legally release an act’s output across the planet on a limited budget.

What is seldom mentioned in this bargain is that, without a proper marketing allowance, the visibility of any such release would be extremely limited. There is more than six centuries’ worth in time of available music in streaming services worldwide. According to Daniel Sanchez, 99 per cent of all music streaming on Spotify and Apple Music comes from the top 10 per cent of songs. Less than 1 per cent of streams accounts for music other than what is popular, according to charts and sales graphics.¹⁷ In essence, only those with the financial means to market a release by advertising on streaming platforms acquire visibility. Rather than implementing solutions for this discrepancy, music streaming platforms like Spotify and Apple Music admit to making money from advertising indie artists. Thus, listeners are put under the illusion of freely choosing what new music they would consume. The total production costs of Listana’s 2013 release, with its recording, mixing, mastering, promotion photography, artwork design, music video production and digital publishing costs, were roughly 1,200 times higher than all the revenue from the released music.

Conclusion

In conclusion, the metal band experience enriched me both as a musician and a scholar: the most important revelation is that the procedure itself is sometimes even more important than the product. Listana had to remain dormant for some years now due to the pressures of academic career, family obligations and the declining economic situation in Turkey. However, if a project is close to one’s heart, it can never be too far from the mind. I plan to resume both the work and the dream, armed with more skill and knowledge this time, of documenting the glocal and global metal music industry from within by doing practice-led research within the field.

If you are a metal fan, the chances are that you will also play a musical instrument, or perhaps several instruments. However, for readers without any formal musical training, the word timbre might still not be familiar, although musicians are likely to have a well-developed sense of timbre without realising it. So, what is timbre, and why does it matter in metal music? When asked to describe a sound, a musician might use a combination of direct or metaphorical language: ‘the bass is woolly’, ‘the kick drum needs more punch’, ‘the guitar is very harsh’.¹ This kind of descriptive vocabulary can present an obstacle for people who want to measure or manipulate sonic perceptual characteristics, such as musicians looking for a certain sound, producers responding to a client description, or engineers designing tools like equalisation or distortion algorithms. Essentially, the language of timbre is a way to communicate with others about the sound we hear. This extends beyond performance or recording and includes describing our experience of listening to music. For example, production critiques often fall instinctively under the purview of timbral analysis.

This chapter first introduces timbre from a formal point of view and reviews some specific metal-centred timbral studies from literature. Next, we look at the use of technology to meter timbral attributes. Finally, the chapter reflects on the ability to implement a machine learning system, a type of data-driven learning that falls under the umbrella of artificial intelligence, in music production tasks, which has borne fruit in automated mastering and mixing in recent years.² This chapter gives a brief overview of how these ideas work and how they might speculatively be implemented in the context of metal music and timbre, particularly with examples looking at convolution and tone matching.

Defining Timbre (‘Then’)

Listeners often struggle to describe their experience of music to others in a meaningful way. What do adjectives like ‘warm’, ‘punchy’ or ‘heavy’ really mean, and how can listeners, musicians and producers exploit this knowledge? To get a handle on timbre, we need to set a few definitions. The American Standards Association (ASA) defines timbre as ‘that attribute of sensation, in terms of which a listener can judge that two sounds having the same loudness and pitch are dissimilar’.³ This definition can be considered a difficult starting point, as it does not define what timbre is but rather what it is not. To illustrate this difficulty, we can consider unpitched or environmental sounds that would, according to the ASA definition, have no timbre. A more satisfactory definition is commonly given as ‘the sensation on whereby a listener can judge that two sounds are dissimilar using other criteria than pitch, loudness or duration’.⁴

Tone colour and sound quality are terms that might be used synonymously with timbre. However, tone colour can imply that the spectral properties of the sound are solely responsible for its timbre, contradictory to research specifying the importance of temporal acoustic correlates with relation to the perception of timbre.⁵ What this tells us is that timbre is a psycho-acoustic attribute. This means it is a perceptual parameter, something which is slightly different for each of us, but which has underlying acoustic contributing factors that can be quantified.

Fans of metal music are, in fact, particularly well trained for timbral analysis, as they will have a sense of what ‘heavy’ means and be familiar with at least three categories of instrumental timbral attributes: distorted guitar tones, screaming vocals, and polished closely microphoned and/or triggered drum sounds.

Metal Specific Timbral Attributes (‘Now’)

Let us consider our metal-specific timbral attributes in more detail. We might consider an ontological pyramid containing our descriptors, perhaps with ‘heavy’ at the top of the pyramid, as it pertains to individual instrumentation, the overall mix, lyrical content, and indeed the semantic whole of a performance. Below this, we might see our flavours of distortion, both for bass and guitar, perhaps then broken into smaller descriptors like ‘bright’, ‘dirty’ or ‘chuggy’. Similarly, the second layer might feature other instruments, with a category for drums having sub-categories that include descriptors like ‘punchy’. Perhaps the most unique and challenging of this second layer will be our category for vocals. There are very few genres of music with as much variety of timbre in their vocal delivery. To illustrate this, imagine a line of lyrics being delivered at the same pitch, loudness and spatial placement, but by different vocalists. Let us take Chris Barnes, the original vocalist of the death metal band Cannibal Corpse. The third layer of the pyramid might now include timbral descriptors like ‘growly’ or ‘death grunt’. We might imagine a rather different vocal timbre if Barnes was replaced by, for example, Till Lindemann from the German industrial metal band Rammstein. Lindemann has a larger range than Barnes, and in German musicology, there is even a word for the type of spoken-word singing style he employs with Rammstein, Sprechgesang, literally spoken singing and not limited to the world of metal. For example, in the operatic idiom, it would be perfectly acceptable to mark a passage as Sprechgesang for singers. But in the metal world, we might fill our third layer of the timbral pyramid for Lindemann with descriptors like ‘breathy’ or ‘raspy’. The vocal sound we hear in this case is a combination of several factors, including Lindemann’s own performance, but also very much reliant on sound engineering and music production techniques. Closely microphoned vocals lend particular timbral properties, as does the use of dynamic range reduction, also known as compression. We also have, and often use colloquially, a generic timbral descriptor when considering metal vocals: ‘clean’. In genres like metalcore, for example, vocalists might switch between a clean and a dirty style. These examples illustrate how psycho-acousticians borrow descriptors analogously from other domains, with ‘clean’ being semantically at the opposite end of a bipolar scale to ‘dirty’.

‘Heaviness’ sits at the top of our pyramid of metal timbre. We all have an idea of what it means, and it pervades each of the lower levels of timbral attributes and their constituent descriptors. In the last fifteen years, we have started to see serious attempts by scholars and practitioners in qualifying and quantifying what we mean by this. We find across the literature qualities related to denser or distorted guitar timbres, perceived rhythmic difficulty,⁶ and multiple combinations of perceptual and acoustic correlates.⁷ The mechanism of distortion itself is quite well-known: additional harmonic overtones are added (perhaps with some inharmonic or noisy content) in particular ratios, which are akin to the physical sensation of distortion a listener might experience if their auditory mechanism was overloaded by a very loud sound in the real world. By rights, distortion should be a bad thing in sound engineering, and many technical training devices exist, which seek to teach the listener to identify and remove unwanted distortion. But in metal timbres, the key distinction is between wanted and unwanted distortion. Because of a technical focus by the sound engineering community on the latter, there are acoustic methods for describing distortion, both linear and non-linear types. As such, we can see that distortion is an acoustic parameter first and foremost, but it, in fact, has timbral descriptors that we might anchor to it, for example, ‘clean’ or ‘dirty’ as mentioned above, but also including ‘crunch’. The difference between acoustic shape and type of distortion is of particular interest to metal, as the non-linear distortion found in overdriven tube amplifiers has a markedly different perceived response in listeners to linear distortion.⁸ There are also studies suggesting that musicians and non-musicians have different responses to distorted timbres.⁹

By contrast to the favourable type of distortion, the drums in a metal performance are typically preferred to be ‘clean’, or other descriptors we might expect, such as ‘punchy’ or ‘clicky’. There are always exceptions. Industrial metal, for example, has made creative use of distorted drums over the years. In modern metal drum sounds, we see a different lens passed over the timbre, then, that of realism and performance augmentation, whether it be through close microphone techniques or, more commonly, drum replacement and sample triggering strategies. For a detailed overview of the process of fine-tuning metal drums at the point of production, the interested reader might visit Mark Mynett’s articles for Sound on Sound magazine,¹⁰ which lift the curtain on these processes.

Applying Timbre in Performance and Production (‘Next’)

There are times when the lens of history allows us to see how timbre can be as fickle as fashion. In the mid-1990s, technology had sufficiently evolved to the point of being able to shape the production aesthetics of metal, giving rise to a new sub-genre: nu metal. Ross Robinson was arguably its most successful producer and had a distinctive sound characterised by a series of timbral attributes: detuned guitars or a ‘ticky’ bass sound. The first Korn record, Korn (1994), for all these trappings, is still a remarkably dynamic record, so much so that it features on recognised mastering engineer Bob Katz’s shortlist for records deserving of praise in the face of the loudness war. Thus, we might consider a place somewhere in our timbral pyramid for the attribute set, which corresponds to specific sub-genres in metal. It has useful applications for listeners in terms of classifying their own choices of music and thus finding or recommending new music they might like. But beyond this, many examples are possible, taking advantage of recent advances in processing power and availability of digital signal processing, for example, digital convolution and the availability of machine learning techniques.

Proposing an AI Approach

One such example would be to propose tools that would allow us to harness what we know about metal-specific timbral features in our own music-making activities – whether as a performer, producer or simply a listener – using an artificial intelligence (AI) or machine learning approach. One example of a machine learning model would be a supervised learning algorithm. In our metal example, we could extract acoustic features from a dataset, for example, spectral centroid, which is correlated with bright guitar tones. We mark up the relative timbral descriptors for our example tones. The algorithm then seeks to discover how much of each acoustic feature there is in the brightest of tones and applies this as a weighting to each feature in the dataset. We now have a marked-up dataset of guitar tones with a series of weighted features contributing to specific timbral descriptors. Imagine now that instead of having traditional equalisation controls on your guitar amp (e.g., bass, middle, treble), you now have ‘brightness’, ‘sharpness’, ‘heaviness’ and other timbral descriptors of your choosing, trained on a dataset of metal tones that you enjoy.

Over a recorded audio mix, this tool might allow you to meter timbral qualities in your mix versus that of a reference mix that you, or a client, particularly enjoy. In fact, automatic mixing is one such example of which machine learning has already made great strides towards, and the LANDR platform uses exactly this technology in the world of music mastering.¹¹ Historically, an engineer or producer might spend many tedious hours automating a volume fader of a particular source – typically the lead vocal – to make sure that it sat correctly in the balance throughout a song. This can be a time-consuming process if done by hand, but it can be automated, freeing the engineer up for more creatively challenging, and ultimately enjoyable, work on the rest of the mix.

Beyond this, we might imagine future work combining machine learning for parameter control with the power of digital convolution going beyond tone matching and amplifier profiling and instead facilitating the creation of entirely new timbres. This process owes a lot to morphing,¹² in which a new timbre is created combining particular timbral attributes from two source sounds. It is, of course, impossible to predict what creative people will do with new tools once they become available. We can see historical examples of creative use of misused technology: the distortion created with electric guitar amplification was originally created by misuse of the amplification chain; equalisation that can now be used to carefully craft mixes, individual instrumental and vocal timbres was originally a tool to correct problems in the frequency response caused by telephony; sampling that in the metal world has given us consistent – perhaps overly consistent – kick drums, more or less gave rise to an entire genre in the shape of hip-hop music.

Feature-based Comparison as a Machine Learning Classifier

The following section provides a walk-through or ‘thought exercise’ as to how the ideas and techniques discussed earlier in this chapter might manifest in novel audio signal processing algorithms. It is important to emphasise that, at the time of writing, the idea illustrated here is somewhere between the realms of what we know now is possible and science fiction.

First, let us reiterate our goal: We imagine a technology that might apply acoustic measurement of specific features to describe the timbral attributes of a particular mix, perhaps in a sub-genre of metal, or with a desirable production characteristic – essentially, a well-mixed piece of music. Heaviness might be the goal, or clarity, or energy, or any number of timbral attributes that we enjoy in a song, album, artist or genre. We consider these as a hierarchical pyramid of idiom, with artists resting on a foundation of genre or sub-genre, and albums and songs on top of, or as divisions of, the artists’ sound.

Why do we need this technology? To assist the artist in realising a sonic goal for an album or song in the context of the genre. There are, of course, sonic characteristics that we might ascribe to any of the layers of the pyramid described previously, but that are difficult for anyone outside of highly skilled production or engineering to really achieve. To put this in the simplest layman’s terms: would it not be great if you could make your own recording sound exactly the way you want? This need not mean exactly like someone else’s recording – although matching equalisation, loudness or distorted guitar tones is a common task for the working recording engineer – but rather a platform that allows a vocalisable production quality to be achieved by an artist. Those of us who have experimented with recording our own music will know the frustration of ‘bad’ recording or poor production quality more generally. Indeed, metal music more widely requires excellent production in comparison to many other genres, such as garage rock, which prizes a ‘rough and ready’ production style. Metal requires careful manipulation of the frequency spectrum, an understanding of harmonic distortion, triggering and phase in multi-microphone drum kit situations, and a host of other technical and aesthetic production decisions. In short, producing good-sounding metal is difficult.

Technology might now assist us, as many of the elements of production mentioned above are nowadays computer processes that operate on specific acoustic parameters. However, that would only be useful to our wider audience if such technology can first perceive the necessary processing differences. Thus, our goal is initially in metering, or machine listening. This gives us three questions:

1. (1) What does our machine hear (source)?

2. (2) What is its goal (target or training material)?

3. (3) What processing might then be required to bridge the gap (action)?

Here, we have stepped into science fiction, although just barely, as the world of machine learning is advancing so quickly that even at the time of writing, we see this paradigm in deep fake news items.

For the purposes of this chapter, let us illustrate this with a real-world example of the first stage – what does our machine hear – which is entirely possible already. Indeed, we could train a classifier, in machine learning terms, to deal with endless examples in the same manner, essentially creating the first stage of our machine listener: a meter. For this, we use audio stems of the main instruments of ‘A Secret Kiss’ from British doom metal band My Dying Bride’s 2020 album Macabre Cabaret.¹³ We are particularly interested in the elements that our production aid might help with: the relationship between the timbre of the guitars, the bass,¹⁴ and the kick and remaining drum balance. We therefore analyse four stems: guitar, bass, kick drum and remaining drum mix.

Acoustic Feature Extraction

We extract the following features from each audio stem:

• Spectral centroid: A spectral ‘centre of gravity’ and commonly used psycho-acoustic parameter in music analysis (e.g., high-hats will have a higher spectral centroid than a kick drum), especially as a correlate for ‘brightness’.

• Spectral spread: The ‘instantaneous bandwidth’ of a spectrum, used as a metric for tonality, where if a pair of tones converge, the spread decreases (e.g., we might expect a smaller spectral spread for harmonic distortion than inharmonic or partial distortion on a guitar tone).

• Spectral skewness: A degree of symmetry around the spectral centre, also known as ‘spectral tilt’ in speech analysis, indicating the relative strength of harmonic and fundamental content (e.g., useful in the analysis of the amount of distortion on both guitar and bass stems). A positive skew indicates the fundamental is more dominant than the upper harmonics or tones. In our case, power chords are the most relevant.

• Spectral decrease: The measure of the decrease in a magnitude spectrum. This parameter is not often seen in speech analysis but is common in musical instrument recognition (e.g., if we want to discriminate between an analysis of drums in a stereo mix and features that are guitar-driven, we might expect a minimal decrease in guitar spectrum, with a much more dynamic result in the spectra of the drums).

• Spectral flux: A simple metric of the amount of change in the spectrum over time (e.g., how consistent is the spectrum in the stems or the finished master we are listening to. This is especially interesting if we are considering emulating multiband compression parameters).

• Spectral roll-off point: Like the spectral decrease, a marker of the bandwidth of a signal over the total energy, helpful for instrument separation and also common in music genre classification.

• Spectral crest: A ratio of the peaks to the mean average (e.g., to reveal the amount of creative, production-informed compression).

• mel spectrogram: A pitch-related plot.

• mel-frequency cepstral coefficient delta-delta: A speech-derived correlate, which shows the rate of change in the spectrum of the spectrum (e.g., useful for reducing complex spectra to their most relevant components).

We might consider training our model on many more acoustic parameters, but the list above gives features that might be most useful in the analysis of metal production timbres.

It is beyond the scope of this chapter to provide each figure but let us examine some types of visualisations and consider a simple example from our sample material.

Figures 6.1–6.5 show a few of the types of visualisation we can produce to help our understanding of the numerical properties, which acoustic feature extraction produces. Sound engineers will likely be familiar with two of these types of presentation: (1) visualisation in the time domain, with time on the X-axis (as we see in common digital audio workstations when a waveform of a sound signal is presented); (2) visualisation in the frequency domain, as in the mel-spectrograms, which show us amplitude (using the colour of the signal), time on the X-axis, and frequency on the Y-axis. As such a representation is 3D, we can rotate it as in the spectral skewness plot. In these figures, we can start to see immediate differences, as indeed we would hear them if we listened to the stems.

Figure 6.1 The spectral skew of the drum stems, rotated. It shows how the shape of the frequency content differs below the centroid in comparison to the mean. We can interpret this as being quite low-frequency-dominant, as might be expected from kick drums, but with a certain amount of time-varying, evenly distributed mid and high frequency content. Note the highs, in particular, remain very even and relatively smooth

(© Duncan Williams)

Figure 6.2 The mel-spectrogram of the kick drum. The interesting section at between 1.5 and 2 minutes is a section using a double pedal. Note that although there are marked amplitude differences, the frequency content of each instance of the kick (on the vertical axis) is markedly similar, suggesting multiband compression or triggering and a similar amount of reverb on each kick throughout the mix

(© Duncan Williams)

Figure 6.3 The spectral flux of the kick drum. Note there is limited spectral change, with a more marked drop in flux around the double pedal section

(© Duncan Williams)

Figure 6.4 The mel-spectrogram of the guitar stem. Note a much fuller spectrum compared to the kick stem, with rich harmonics above the fundamental frequency up to a scooped region at approximately 3 kHz, with little to no content above the ‘fizz’ of 7 kHz

(© Duncan Williams)

Figure 6.5 The spectral flux of the guitar stem compared to the relatively consistent spectral flux of the kick drum stems. This is a measure of change – how quickly the spectrum in each signal changes. Note the much greater variation in the guitar spectral flux, as opposed to the highly consistent measures from the drum stems

(© Duncan Williams)

The next step of the AI learning process would be to train our machine listener to recognise these feature changes in order to provide novel metering or even suggest parameter adjustments based on a set of training material, for example, any set of stems the artist enjoyed and wanted to emulate. Note that we are not suggesting that sound engineers should be made redundant or that the art of record production might be reduced to a sequence of algorithms. New music will always require creativity and artistic interpretation. However, we might envision tools to take away some of the tedious learning curve in music production tasks and facilitate more creativity.

To spare the reader a complete overview of machine learning in the analysis of a training set, we will provide the shortest possible example here: let us say we want to emulate a guitar sound from a stem and therefore train a meter on the parameters listed above. First, we need to train our meter by linking the acoustic features in various ratios to a dependent output variable, the timbral descriptor. We then try a new input, which is classified according to the same features. The difference between source (our new input) and target (our training material) gives a suggestion for changes in a number and ratio of acoustic features. For example, to raise the spectral centroid, we might have a suggestion for some boost in the upper-frequency EQ of the guitar. Our fully-realised system could then analyse the performance of this output in comparison to the input target (in machine learning terminology, this step is called validation), and adjust the suggestion according to ‘how far out’ it was (in machine learning terminology, this is the error function). We can see this type of classifier-optimisation problem in almost any example of machine learning. We end with a system that makes some recommendations in terms of audio production character, including EQ, dynamic range, harmonicity of distortion, amount of distortion, balance between harmonic distortion and fundamental frequency, spectral rate of change. All of those are measured from our acoustic analysis parameters. However, we are not bound by the suggestions. This is a jumping-off point, which might take the next generation of musicians in directions that are, at the time of writing, rather unimaginable, but no less exciting for it.

Conclusion

Psycho-acoustic research generally regards timbre as one of three perceptual attributes of sound along with loudness and pitch. This list of perceptual attributes can be expanded to include perceived duration, location and reverberant environment. These are essentially a series of cues about the spatial properties of the sound source or, in the case of a mix, placement of a sound source in one, two or three dimensions: width, depth and height. The range of perceptual descriptors included in timbre studies is reflected in their acoustic correlates and the lack of a unidirectional scale suitable for timbre. Subsequent research has endeavoured to quantify these interrelationships in an effort to move towards a robust measure of timbre, usually through a combination of acoustic analysis and perceptual testing. The acoustic correlates of timbral descriptors determined by these approaches include harmonicity, which is particularly relevant for the distorted guitar, and various combinations of amplitude envelope and spectral or spectro-temporal variation.

Metal has its own specific timbral descriptors, which are a combination of performance and technology, all of which can fall under a pyramid with ‘heavy’ encompassing each subsequent timbral attribute. Vocal performance styles like growling and screaming are almost uniquely found in metal, and much like the distortion used in guitar or bass, and the triggering and layering used in drum production techniques, the technology can be used to enact large metal-specific timbral variation at the point of recording, mixing or live reproduction. Some work has been done by researchers looking at these metal-specific descriptors in the same vein as work by earlier psycho-acousticians, who looked at correlates for other timbral and perceptual descriptors like loudness and pitch. In this work, we see that timbral attributes can be either acoustical or descriptive, and some descriptive terms have been shown to overlap or agree in terms of their acoustic correlates. The nomenclature is mostly universal, although a large number of labels and descriptors have not been acoustically quantified as yet.

Work to reduce the range of descriptors, perhaps down to those which are acoustically independent, and a subsequent set of those with acoustic overlap, would be useful for our ‘next’ ideas. Similarly, attributes with acoustic overlap, or indeed attributes, which appear to have contradictory acoustic correlates, would also require the ratio between their acoustic correlates to be quantified (timbre metering, matching and designing). In the ‘next’ ideas, we can imagine a combination of these approaches with the now-readily available level of machine learning techniques to provide tools for musicians and producers that will help with timbre: to match existing timbres (streamlining the search for a good guitar tone or emulating favourite tones) and, perhaps most excitingly, to craft new timbres.