One of the most frequently misunderstood genres of popular music, heavy metal traces its origins back to the late 1960s, as the hippie movement began to burn out and hard/acid rock bands began to proliferate, bringing with them a new, hard-edged style of guitar playing. For instance, many consider The Beatles' "Helter Skelter" the first heavy metal song while the electric guitar legend, Jimi Hendrix, is credited as a major inspiration with the story that a supposed music magazine article described his music as "like bars of metal raining down on the stage."
The genre was truly born when an obscure little English band known as Black Sabbath fused this sound like raunchy, aggressive blues routines on their 1970 self-titled album. The band's morbid Crapsack World imagery and Tony Iommi's signature aggressive guitar riffs became wildly popular with young people on both sides of the Atlantic, much to the consternation of their parents and the newly un-hip '60s "flower generation". Despite the controversy (which would persist and mutate into different forms as heavy metal itself evolved), Black Sabbath enjoyed brisk album sales and a sizable fanbase.
If Black Sabbath was the Ur Example of heavy metal, Judas Priest and Deep Purple were certainly the Trope Codifiers. They provided a faster, smarter variation on Black Sabbath's crushing riffwork, mixing razor sharp riffs, agile leads, and the earliest examples of the dramatic, high-pitched vocals and searing "Metal Scream" that would become almost synonymous with metal in the mid-to-late 1980s. Fast-paced burners like "Highway Star", "Tyrant", and "Exciter" stripped away Black Sabbath's blues baggage, providing a sound that was nothing short of revolutionary. Unfortunately, it turned out to be too revolutionary for the conservative '70s rock scene and heavy metal enjoyed limited mainstream success at this time.
The source of the name "heavy metal" is, like most things to do with metal, hotly debated. Those who prefer a more "high culture" or "respectable" inspiration point to characters called "the Heavy Metal Kid" and "Heavy Metal People" in works by William S. Burroughs. Lowerbrow types often point to the line "heavy metal thunder" in the proto-metal hit "Born To Be Wild" by Steppenwolf. More generally, the word "heavy" had been used for a long time among hippies to mean "serious" or "depressing", and some people point as well to the group of often-toxic chemical elements known as "heavy metals" in chemistry.
Heavy metal largely fell under the radar in the late 1970s as Black Sabbath began to fall apart at the seams and the new sensation of punk music, providing much of the aggression of heavy metal in a rawer, stripped-down package to appeal to a music-buying public sick of the theatrics of Progressive Rock. However, the success of British punk bands was providing fresh inspiration to a new generation of metal musicians, who blended the gritty, street-smart anger of punk with the drama and bombast of heavy metal. In late 1979, the New Wave of British Heavy Metal (NWOBHM) exploded onto the British music scene, bringing with it new bands like Motorhead and Iron Maiden that were faster than Priest, louder than Sabbath, and angrier than The Sex Pistols. The collapse of the original punk scene brought even more wind into heavy metal's sails and metal bands began springing up, not only in the UK, but all over America and Europe, and as the genre's success grew, three very different movements were coalescing within a once more-or-less unified genre.
The first movement came from when punk rock's own offspring, the nastier, noisier, more aggressive "hardcore punk", trickled down into a metal scene already amped-up on punk rock rage. Many within the metal scene decided to beat them at their own game and turn it Up to Eleven. British band Venom's 1981 album Welcome to Hell was perhaps the first prominent fruit of the budding extreme metal subculture. Blisteringly fast, stupendously aggressive, and unabashedly offensive with its lurid Satanic imagery and violent themes, Welcome to Hell was perhaps the most aggressive album ever published at the time, and became a lightning rod for controversy from people who claimed that it was subversive, Satanic, and encouraged all manner of social ills. This, of course, only made it more popular with rebellious youth. European "Speed Metal" bands began to one-up each other in aggression, creating a massive metal arms race of chainsaw guitar riffs, frenetic drumming, and new vocal styles that mutated the high-pitched wail that had now become the definitive metal voice into nearly incomprehensible shrieking and gibbering. These early extreme metal albums were raw, uncompromising, and hostile, attracting a small but loyal following of hardcore fans, but were too unpolished and off-putting to crack the larger music world.
Meanwhile, thousands of miles away in southern California, a clique of like-minded musicians were working on a curious fusion of socially conscious street punk and the more melodic, intellectual strains of NWOBHM as a second wave of social upheaval began to sweep America in the first half of The Eighties. The seeds of what would become thrash metal were being sown with provocative, often sarcastic lyrics, a rigid, driving sense of rhythm, and extensive use of palm-muting, which was used to create long, choppy, often highly intricate staccato passages with a crunching, almost mechanical sound. This new sound had much of the aggression of European extreme metal (which was still several years away from achieving significant recognition in the US) but a much higher standard of musicianship and a more social, political bent (which would become Flanderized in the later 80s into what some called "CNN thrash").
Metallica were the first thrashers out of the gates with their 1983 debut Kill 'em All. The distinctive guitar styles of James Hetfield and Dave Mustaine (who, although already departed from the band, arguably had far more impact on Metallica's early style than his replacement Kirk Hammett) and tougher, more masculine imagery of the band themselves were a hit, and they were quickly joined on the scene by not just other thrash founders like Exodus, but dozens of followers like Megadeth (masterminded by an enraged Dave Mustaine trying to one-up Metallica), Testament, Slayer, and others. The thrash movement spread across the America but truly found second homes in New York, where Anthrax and Overkill infused an extra dose of punk elements to create a pounding, crowd-pleasing "mosh" rhythm and acerbic Deadpan Snarker attitude, and in Germany, where it intermingled with European extreme metal to fuse the best of both worlds, springing bands such as Kreator, Sodom, Tankard and Destruction.
At the same time, the mainstream music business had gotten wise to the burgeoning success of heavy metal and were busy making a more accessible, radio-friendly version, infusing metal elements into glam and arena rock to create a form of music that has at different times and places been called "glam metal", "pop metal", "Eighties metal" (a serious misnomer as there were plenty of other forms of metal at the time), "Hair Metal", and other more unflattering terms. Glam metal featured a bouncy, dance-friendly beat with an exaggerated echoey "gated" snare tone (just think "Eighties drums" and you'll get the general idea), a mixture of aggressive distortion and sugary mainstream-friendly guitar work, a scaled-back, more rockish variant of the Metal Scream, and a sleazy Hotter and Sexier image with androgynous musicians in highly sexualized outfits, raunchy lyrics that often centered around prostitution, sex, drugs, and L.A./Vegas nightlife. While reviled by the core metal faithful from its very inception, glam metal became outrageously popular, and many "vanilla" heavy metal bands like Def Leppard, Tygers of Pan Tang, and, most infamously, Judas Priest, jumped on the bandwagon after the diversification of the metal genre took the wind out of NWOBHM's sails.
The period between 1985-1990 is widely considered the golden age of heavy metal and was the zenith of the genre's popularity and influence and filled with many of the genre's most esteemed classics, but even in these heady years the forces that would create heavy metal's downfall were beginning to manifest. As the Eighties progressed, the formerly quite distinct divide between American and European metal blurred and the various strains of metal began to hybridize. In continental Europe, the "vanilla" heavy metal had taken a different path from that in the US, becoming more and more refined and intellectual in nature as a contrast against the raw fury of extreme metal, which was by now starting to congeal into a cohesive scene that would one day be known as black metal. While this "power metal" had analogues in American bands like Queensrÿche and Manowar, it was far more popular in Europe, where bands like Iron Maiden (not a power metal band itself, but the first significant "thinking man's" metal band and the most important progenitor of power metal) Helloween, Yngwie Malmsteen's Rising Force, and others were wowing metal fans with high-flying instrumental theatrics and escapist, fantasy-oriented lyrics. Power metal and progressive rock, which was now losing the bad reputation it had acquired in the 1970s, spawned a host of new "white-collar" American power metal bands like Queensryche, Fates Warning, and Crimson Glory.
Thrash metal also felt the influence of power metal. Thrash had always had a technical, "musician's music" streak with its penchant for lengthy compositions like Metallica's "The Four Horsemen" and Exodus' "Deliver Us to Evil" and noodly "shred" guitar solos, but a new wave of "technical thrash" or "tech thrash" bands took this to an extreme. Bands like Forbidden, Toxik, Watchtower, Coroner, and Heathen reveled in multilayered compositions and tricky, jagged rhythms, and even the more mainstream elements of the subgenre got in on the act--Metallica's 1986 and '88 albums Master of Puppets and ...And Justice For All had songs that approached the ten-minute mark and Dave Mustaine recruited a succession of guitarists from the highly musician-oriented fusion jazz scene (most notably neoclassical virtuoso Marty Friedman) for Megadeth, their practiced chops providing a striking contrast to his wild and creative leads. Two- and three-guitar bands proliferated as guitarists throughout the metal scene reveled in playing off each other and "dueling" with elaborate solo passages.
The extreme-influenced, harsh, German strain of thrash metal was now also taking root in America, and a number of bands in California and Florida were putting a violent new twist on it. The new "death metal" scene resembled thrash but was clearly not thrash, with heavily down-tuned, percussive, hammering riffs, a fixation with gruesome, horror movie-like violence, and the harsh screaming of ordinary extreme metal further mutated in gurgling, monstrous growling noises. The impact of Possessed's Seven Churches and Death's Scream Bloody Gore was felt on both sides of the Atlantic, signaling a new wave of extreme metal as death metal took the US metal faithful by storm and Europeans, especially in Sweden, put out their own variations on the genre.
As the metal hardcore continued their campaign of one-upmanship, Glam Metal was now one-upping everyone on the charts, with singles by bands like Def Leppard and Motley Crue shooting to the top of radio playlists and selling millions of records to a mainstream largely ignored by the "true" metal bands. But this success came with a downside--glam metal's sleazy "sex, drugs, and rock and roll" image had become The Theme Park Version of heavy metal, a stereotype that was beginning to overrun the whole genre in the eye of the general public, and many were becoming discontented with the glamour and glitz of the L.A. glam scene. The media labeled them as a bad influence, fickle, style-conscious youth began to see them as posers, and most of their contemporaries were becoming either too esoteric or too extreme to appeal to the average consumer, leaving no ready replacement. As The Eighties turned into The Nineties, even as the record industry were drunk on the genre's success and former bad boys Metallica came within a hair's breadth of taking home a Grammy award, the scene suddenly collapsed.
By 1990, the writing was on the wall--the genre was already oversaturated with a raft of subgenres and thousands upon thousands of bands, but the genre's momentum kept it going until Nirvana released their album Nevermind in 1991. Suddenly the youth of the Nineties had found their icon, which not only reflected the angsty new cultural zeitgeist, but seemed simpler and more "authentic" than the glam scene which had now become the face of heavy metal to most people and weren't as unapologetically anti-mainstream and inaccessible as thrash and power metal. The grunge movement soared to prominence in the music scene with the same sort of overwhelming force as punk in the late 1970s and, ironically, heavy metal itself in 1979-81, many of the metal acts that were signed to major music labels were betrayed by their own publishers and sidelined in favor of hip new alternative rock bands. Some metal bands, most notably Metallica with their self-titled "black album" and glam-cum-power-cum-thrash metallers Pantera, who abruptly broke all ties with their past and advanced a stripped-down, testosterone-heavy "groove metal" with 1990's Cowboys from hell, managed to achieve commercial success during this time. Still more heavy metal bands, faced with the choice of abandoning their scene or being buried, simply quit. By 1993, heavy metal was being used as a punch line on Beavis and Butthead and the genre seemed dead.
In truth, the genre had come close to dying, but remnants of it had survived, especially in Europe, where glam metal and grunge had much less impact than in the US. Helloween rose from a second-tier speed/power metal act to a megahit with their Keeper of the Seven Keys duology, which focused on catchy vocal melodies, a more light-hearted Lighter and Softer attitude, and influences from synthesizer-heavy European pop music, spawning hundreds of imitators throughout The Nineties. Dream Theater created a modest but enduring fanbase by taking the progressive rock influences on power metal and running with them, merging metal and prog-rock into a unique new "progressive metal" sound that found a following with people who wanted something "smarter" than grunge. Their sophomore effort Images and Words sold 800,000 copies despite being released at the height of the grunge craze. Black Sabbath survived by ignoring most of the developments of the 80s and returning to the bluesy, stomping proto-heavy metal that had carried them through The Seventies, culminating in a brief resurgence of fame as they reunited with former frontman Ronnie James Dio for the 1992 album Dehumanizer, which is still highly regarded to this day. Death metal, a niche genre to begin with, maintained a small but devoted fanbase. And a group of musicians in Norway had turned the chaotic extreme metal scene into a coherent musical movement that would gain notoriety far beyond its small fanbase.
This new movement was called black metal, an evolution of the violent extreme metal bands of The Eighties that was fiercely independent, virulently anti-mainstream, and even more provocative than its antecedents. Many of them believed that metal was doomed the moment it courted the mainstream, and cultivated a sound that was as exclusive and "out there" as possible. With deliberately muddy production, extremely harsh soundscapes, and anti-Christian lyrics that ranged from God Is Evil to literal Satanism, black metal was the ultimate in cult fandoms (and some people have literally compared the early scene to a cult). While the movement was very small, often with album sales in triple digits, black metal musicians became most identified with a sort of cultural jihad against Christianity, with outrageous anti-religious statements, disturbing imagery featuring Satanic symbols, bondage gear, and ghoulish makeup, arsons and other attacks on churches and other Christian cultural sites, and identification with Norse mythology (whose association with Those Wacky Nazis was milked for all it was worth). The scene spread slowly but surely, first in Scandinavia and then worldwide, with black metal bands springing up in America, Eastern Europe, and even Japan.
The tide begin to turn for heavy metal as The Nineties gave way to the Turn of the Millennium. The resurgence of heavy metal had a
false start of sorts with "nu metal", which was not heavy metal at all, athough it was marketed as such is extremely controversial, to the point where arguments about its metal status even occur on this page. This Darker and Edgier spin on alternative rock/metal with its "chug" riffs and angst-ridden relationship themes was popular among teens and tweens from 1998 to around 2001, but never caught on the actual heavy metal community and was slapped with the derisive label "mallcore" by its detractors. However, it did show that the public had warmed up again to the idea of "metal" and that the genre could be viable again. With the dawn of the 2000s, heavy metal began to crystallize into a major scene once more as the Internet allowed metalheads across the world to come together and share their fandom. Many major metal bands of the "golden age" reunited or otherwise got a second wind, most notably Iron Maiden, who reunited with longtime singer Bruce Dickinson and released their comeback album Brave New World in 2000 to rave reviews. Judas Priest got back Rob Halford, Black Sabbath got back Ozzy (although that reunion never really went anywhere), and underground legends Jag Panzer started releasing albums again. Dream Theater was now leading a whole host of progressive metal bands that found great popularity in Europe and Japan. Power metal was becoming a sensation in northern Europe, with bands like Helloween, Stratovarius, and Sonata Arctica experiencing considerable success. The time was ripe for a comeback.
Around 2005, the genre took off like a rocket. The site Metal Archives, devoted to cataloguing every metal release ever made and providing a focus for the online metal community, gained widespread popularity and raised awareness of the older 80s subgenres. Rhythm games like Guitar Hero made guitar solos cool again, and modern metal bands like Dragon Force (video game) used their chops to enthrall a generation sick of Three Chords and the Truth. Even more metal reunions sprung up, and metal bands started breaking the top 50 on album charts in their opening weeks. By 2006, thrash metal was experiencing its first major wave of popularity in 15 years, with a raft of new "thrash revival" bands perpetuating the style in modern times. Since then, the scene has only continued to grow despite occasional cries of They Changed It, Now It Sucks and It's Popular Now It Sucks. Black Sabbath reunited with Dio again under the banner of Heaven and Hell and their new debut album has become an instant success. Although the genre is nowhere near as popular as it was at its height, its core fanbase is also more stable, metal doesn't seem to be going away anytime soon.
The exact definition of heavy metal is a point of contention even among metal fans, but it is generally understood that the most defining element of heavy metal is the "metal riff", a sequence of chords (usually power chords, but not always) that is both melody and rhythm, and exudes a sense of power, aggression, urgency, weight, or various combinations thereof (in simple terms, it's "heavy"). A typical metal song typically uses several riffs instead of the one or two featured in a normal rock song), varying from a mere three or four to more than 10. Vocal style varies widely, but medium to high, dramatic tenors and guttural shrieks or growls are the most prominent vocal styles. Thrash tends towards gruff shouting as part of its punk roots, and some very conservative metal bands have more traditional blues/rock vocals. Soprano and Gravel is popular among "gothic" and "symphonic" bands. Lyrics vary, but the most universal and popular lyrical theme for metal is death. Virtually every metal band that has ever existed has written at least one song concerning death, and it has a similar role as a dependable standby subject as love does in traditional rock music--you just can't go wrong with a song about death.
Heavy metal is known for its diverse subgenres and styles, which include:
- Heavy metal, also known as traditional metal, trad metal, or "true metal" (although that overlaps with American power metal), is the original style. It usually features medium to fast tempos (although some bands are slower) with a high degree of melody and clean vocals. Prominent examples include Black Sabbath, Judas Priest, and Iron Maiden. Note that what is called Heavy Metal can also be labelled as Power Metal by some, as many Power Metal bands make use of the same tempos as "trad" metal bands.
- Speed metal is relatively hard to pin down, but is generally faster and rawer than traditional heavy metal, with a driving feel. It ranges from relatively tame material like Helloween, to really raw stuff like Venom. It overlaps with both power metal and early extreme metal. Early (1985-1992) X is a good example of speed metal fused with thrash metal and infused with punk sensibility.
- Thrash metal is characterized by its choppy rhythms, frequent tempo shifts, and typically large number of riffs per song. Lyrics tend towards more concrete and less fantastic than other types, often with a political or social bent. Prominent examples include Metallica, Megadeth, Anthrax, Slayer ("The Big Four"), Kreator, Sodom, Flotsam and Jetsam, and Watchtower. The more intellectual forms can overlap with aggressive power metal and the more aggressive forms overlap with death metal. Sometimes mixes with hardcore to form "crossover thrash", as exemplified by Suicidal Tendencies and Nuclear Assault.
- Power metal has a sort of dual origin, having arisen separately in the US and Europe, and mixed later, which leads to a very sharp divide between US and European power bands. As a rule, power metal is more thoughtful and orderly than most metal, with an emphasis on instrumental ability (but not to the degree of prog metal or tech death) and fantastic lyrics. American power metal, typified by Sanctuary, Attacker, Iced Earth, Omen and Savatage, is usually more aggressive, with influences from thrash and Low Fantasy lyrics. European power metal, typified by Helloween, Edguy, Stratovarius, and Blind Guardian, is usually more melodic, with lots of synthesizers, a distinctive "double bass" beat, and High Fantasy or Sci Fi lyrics. Some metalheads look down on power metal and its fans for not being "metal" enough, referring to the genre as "flower metal". Think of American power metal as Robert E. Howard and European power metal as J.R.R. Tolkien.
- Relatively recently, Japan's power metal scene has started to produce its own brand of power metal with bands that cues from European neo-classical metal bands such as Stratovarius and Yngwie Malmsteen's Rising Force. As with their European neo-classical metal cousins, Japanese power metal tends to be fast paced and song writing is based heavily on classical music. Examples of Japanese power metal bands include post-1993 X Japan (before 1993, as mentioned above, it was speed metal/thrash metal outside of ballads), Galneryus, Concerto Moon and Versailles.
- Power metal is also known for the amount of ease that it can be fused with other genres. For this reason, there are umbrella terms like progpower metal for bands that are one part progressive metal and one part power metal such as Kamelot and Symphony X and thrash-power metal for bands that mix thrash metal and power metal such as Iced Earth and 3 Inches of Blood.
- Early extreme metal is a very raw and chaotic style of music, often with little regard for instrumental proficiency and a fixation with being as aggressive and furious as possible. Venom is the Ur Example, and Celtic Frost, Bathory (who are the sort of "missing link between this and black metal), and early Mayhem (who later became a black metal band) important members of the genre. Later evolved into black metal, and mixed with thrash to form death metal. The term "extreme metal" in the modern sense is generally used as a blanket term encompassing black metal, death metal, thrash metal, metalcore, (some) doom metal, sludge metal and other "extreme" sub-genres, along with any other bands that don't neatly fit into any of the aforementioned.
- Black metal is a development of early extreme metal, featuring tremolo-picked riffs, harsh shrieking vocals, "fuzzy" production, and extremely anti-Christian lyrics. The scene has a reputation for violence and criminal activity that is not entirely undeserved. This form of metal is a very niche product and proud to be so, but more commercial offshoots such as Dimmu Borgir and Cradle of Filth have seen some mainstream success. Unfortunately, this is the subgenre that far too many people think of when you mention metal nowadays.
- Due to evolving directy into this genre, the early extreme metal scene is often called "the first wave of Black metal", even though their sound somewhat differs from the early Norwegian scene that codified Black Metal as we know it today.
- Many of the black metal bands who have run with Emperor's symphonic/melodic, synthy black metal sound have deviated so far from the blueprint that they sound more like power metal. Thematic pre-occupations with the devil generally only extend so far as the lyrics, and most modern popular black metal bands have little "kvlt" credibility. Black metal's influence can now be found in most extreme metal bands, and is far from a niche genre - everything from folk (Finntroll) to thrash (Aura Noir) carries examples of genre-crossing from black metal.
- Anti-Christian lyrics are not a requirement for the genre and there is, in fact, a strong Christian black metal scene. However, many fans of the Christian portion of the genre prefer to call it either unblack metal or white metal.
- Death metal is a development of thrash metal, recognized by its gruesome themes involving corpses and gore, and low-pitched growled vocals. Death, Possessed, Morbid Angel, and Deicide are names to know in this style. Started as an American thing, but has a following in Sweden as well. Swedish bands, such as At the Gates, early In Flames, and Edge of Sanity, are lower-key and more refined. Death metal is related to a very extreme offshoot of hardcore punk called "grindcore" that carries a similar ethos. The two often mix to form "death/grind" or "goregrind" bands, which are basically Death Metal carried Up to Eleven and exemplified by bands with such charming names as Circle of Dead Children, Cattle Decapitation, and Anal Cunt. Death metal has a penchant for really disgusting album covers.
- Death metal is also known for its multiple fusion genres, such as with progressive metal (Opeth, later Death albums), NWOBHM (also known as Melodic Death Metal - At the Gates, In Flames, and Dark Tranquillity are generally regarded as the Trope Maker), or power metal (Scar Symmetry). Bands filed under death metal tend to be diverse enough, such that Cannibal Corpse (Trope Codifier for American death metal) might sound to some ears more like Kreator than At the Gates, even though the former is a thrash metal band and the latter, death metal of the more melodic variety.
- Doom metal is essentially a development on very early heavy metal before Judas Priest and other mid-70s bands sped it up. The emphasis here is on slow tempos, huge, crushing riffs, and extremely depressing lyrics. We're not talking "I'm bummed because my girlfriend left me" depressing, we're talking "your life is meaningless and futile, the world is doomed to chaos and terror, and when you die you'll rot inside the prison of your corpse for ever and ever and EEEEEEEEEVVVEEEEEEER!!!" depressing. Really Grimdark stuff. Black Sabbath is the archetype, with the actual style being codified by Candlemass's landmark Epicus Doomicus Metallicus. Don't let the title fool you, it's a very good album. Has spinoff styles called sludge, funeral doom, and drone doom, each of which is slower, drearier, gloomier, and more unbelievably depressing than the last. Not for the faint of heart. Pagan Altar & Witchfinder General in the UK, and Saint Vitus & Pentagram in the US, are Trope Codifiers along with the previously mentioned Candlemass of Sweden.
- While less of a subgenre than a style that is attached to a previously existing subgenre (usually power metal), symphonic metal has become increasingly popular in recent years. Combining aspects of heavy metal with the orchestral drama of film soundtracks and 19th-century classical, Symphonic metal features lush orchestral textures, provided either by synthesizers or a proper orchestra, and often female vocals, which are rare in other forms of heavy metal. More extreme symphonic bands often pair a female clean vocalist with a male harsh vocalist for a Soprano and Gravel effect. Therion is the Trope Maker, Nightwish is a Trope Codifier, with other important bands including Epica, Within Temptation, and Rhapsody. Some (but by no means all) power metal bands add some orchestral sounds to their music, but it only really qualifies as "symphonic metal" if the orchestra is a dominant component of the music.
- Also related to symphonic metal and power metal is progressive metal, which combines the power and aggression of metal with the instrumental technicality and odd song construction of prog-rock. Some of the bands, like Shadow Gallery, also take on classical influences, while others such as Liquid Tension Experiment have a jazz-fusion influence. The genre tends to be focused on Epic Rocking and instrumental technicality. Some well-known bands in this genre include Dream Theater, Fates Warning, Queensryche, Symphony X, Pain of Salvation, Ayreon and the aforementioned bands. There are also quite a few progressive death metal bands around, including Opeth, Atheist, and Cynic.
- Nu-metal isn't actually metal, and is a genre that many metalheads despise that is seen as a combination of various different styles, including grunge, hip-hop, funk rock, hardcore and groove metal. The guitars are usually downtuned, the riffage isn't particularly complex, and the lyrics are often quite angsty. Rapping is occasionally used. The genre is extremely controversial; mentioning it near a metalhead is rather risky. We'll leave it at that...
- Metalcore, while very unpopular among many metalheads, does fall under the heavy metal umbrella, fusing Melodic Death Metal with modern breakdown-oriented hardcore music. Its most iconic features are chugging "breakdowns" (where the tempo and musical complexity are reduced for a period and the band rides only one or two chords), disjointed song structures, and hoarse, shouted vocals alternated with clean poppy vocals that tend to be far tamer in range and intensity than usual metal singing. Important bands include Trivium, Avenged Sevenfold, and Killswitch Engage. It has a derivative called "deathcore" that adds influences from down-tempo "slam" death metal and grindcore. Job For A Cowboy's debut EP is probably the definitive deathcore record. Recently many metalcore bands have begun taking in influences from thrash metal (probably in imitation of Trivium), but most dedicated thrashers are not impressed.
- Sludge metal fuses elements of doom metal and crossover thrash with stoner rock, grunge and hardcore punk. Somewhat peripheral to the metal scene throughout much of the '90s, it was centred around a number of regional scenes, the most notable of which was the New Orleans, Louisiana or "NOLA" scene, which produced such acts as Eyehategod, Crowbar and Acid Bath, while a thriving North Carolina scene produced Corrosion of Conformity and Buzzov* en. The genre was brought to prominence in the mid 90s when now-former Pantera vocalist Phil Anselmo formed Down, a side project which brought together musicians from several major sludge bands. In the 21st century, a new scene emerged in Georgia which gave sludge metal with a progressive, psychedelic rock edge, including Mastodon, Baroness and Kylesa. Many post-metal bands, including Isis, Cult of Luna and Pelican, also incorporated a sludge-inspired sound into their music.
- Folk metal is a style fusing the folk melodies, often (but by no means only) Celtic or Finnish, with metal, usually from one of the more peripheral genres. Its sound ranges a spectrum from black to power metal, with vocals also ranging from growl through Soprano and Gravel to clean singing. What's, then, characteristic of this style, lies (not unlike symphonic metal) primarily in the instruments and themes it uses; you can expect a folk metal band to use at least one violin, or some less common, often traditional, instrument. The lyrics tend to center around a given theme, related to the people whose traditional sounds the band is emulating. The genre started with Skyclad (1990) and Cruachan and Orphaned Land (1994), and earned its respect in 2000s.
- Groove metal (also known as post-thrash metal) is a style that emerged in the early 90s which takes the guitar style, aggressive vocal delivery and technical skill of thrash and fuses with more hard rock-esque song structures and slower tempos. As its name suggests, it has a greater emphasis on rhythm and "groove" than thrash metal. Debates rage as to whether the true originator of the style was Exhorder or the Genre Popularizers Pantera, but in either case it was something of a commercial peak for the genre in the early 90s before the dominance of Nu-metal - Pantera's seventh album Far Beyond Driven debuted at no. 1 on the Billboard charts in the US, easily the most extreme album to do so at that point. Later notable bands in the genre included Sepultura, Throwdown, Machine Head, and DevilDriver.
As a traditionally niche genre that is currently a commercial darling, information about heavy metal is somewhat conflicting these days. The forums and album reviews at Metal Archives will help you understand the metal community. They're not a forgiving forum due to having to deal with Periphery Demographics and trolls a lot, so beware of Internet Backdraft if you decide to post. The black metal scene is the most prominent there too, so if you see someone write something really bizarre and/or offensive, it's almost certainly a black metal fan. Black metallers are... weird.