Mohs Scale of Rock and Metal Hardness

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If you're looking for the scale that ranks the hardness of actual rocks and metals, The Other Wiki has you covered. This one is about music.

Basically, a scale for ranking the "hardness" of music, "hardness" being the quality that separates rock from pop, Hard Rock from soft rock, Heavy Metal from Hard Rock, Death Metal from classic metal, noise from Industrial, and so on and so on.

Unfortunately, it's kind of a difficult concept to pin down, but trying as hard as possible:

  • More guitar distortion is the easiest measure of this. This is also the defining factor that separates metal from rock: guitars in metal sound metallic due to the amount of distortion. It's a bit difficult to classify those rare offshoots from rock that don't use guitars.
    • Similarly, the production quality can play a role. Generally, albums with a raw, unrefined sound lend themselves to sounding hard, and tend to fall towards that end of the scale. Some genres such as Grindcore take this to extremes and deliberately aim for a difficult listening experience as part of their aesthetic. However, as with all of these rules, exceptions can be found, and some of the very hardest bands can have an extremely polished, technical sound, where hardness is distinguishable mainly by other factors.
  • Louder and faster are good, but not definitive measures for this. Generally slow, quiet songs are softer than loud, fast songs, but there are definitely exceptions, though as a rule most hard songs are either loud or fast if they're not both. Funeral Doom and Drone Metal, for example, are both extremely slow but make up for this with extreme loudness, while other extreme genres break up loud sections of songs with quiet sections that nevertheless maintain speeds much greater than most pop music. Additionally, there's an important difference between "loud" and "hard", as a consequence of the Loudness War and variable production techniques - a lot of hard rock and good old fashioned heavy metal has gotten louder over time as re-released albums tend to be remastered with increased loudness, but this does not make them harder, while a death metal cover of a classic metal or rock song probably would be harder.
  • Length of the solo(s) is also a decent measure. Soft songs tend to have no guitar solo, up high in the metal hardnesses often the entire song builds up to the solo. (Of course, there are even more exceptions to this than to the loud and fast rule)
  • How Dark and Edgy the lyrics are, sometimes taking Refuge in Audacity. This is really only tangentially related to how hard the song actually is, but it's really the best measure if you can't figure out exactly how much distortion is on the guitar. A song titled "She Loves You" is going to be a lot softer than a song titled "Blunt Force Castration". Of course, many examples at the Lyrical Dissonance page exist to subvert this phenomenon. See the sister trope, Mohs Scale of Lyrical Hardness, for details.
  • Certain instrumental techniques are more commonly found in heavier rock or metal than in softer varieties: double-bass drumming (where the drummer uses two bass drums, or two bass pedals) is practically ubiquitous in extreme metal, but rarely heard in rock. Similarly, many metal guitarists make heavy use of techniques such as palm muting, tremolo picking and tapping, which tend to be used sparingly, if at all, in rock.
  • A sometimes-useful measure is how conventional the rhythms and melodies are. Most rock, pop, blues, dance music etc., is based around a simple 4/4 or 2/4 backbeat, (occasionally 6/8 or 3/4), and use either a blues scale or a diatonic scale. By contrast, prog-metal or experimental bands make heavy use of unusual rhythms and time-signatures, and extreme metal bands tend to ignore melody for the most part (with exceptions like Melodic Death or Black Metal, and sometimes Progressive Death Metal[1]). However, both unusual melodies and rhythms are very common in some forms of softer music, especially jazz: Dave Brubeck's "Take Five", for example, could easily fit into #1 on this scale, but is written in the very unusual 5/4 time signature with an unusual key signature.
  • As noted below, vocal style (singing, as opposed to shouting, screaming, or growling) is a good measure of hardness, not merely in the style used but in how frequently a particular style is used. It's not especially uncommon, for example, for modern alternative rock artists to use singing predominantly and screamed vocals on occasion, while more mid-range hard styles like metalcore may make extensive use of shouting, while deploying death growls infrequently to add a darker tone to some passages. If, on the other hand, screams or growls are used constantly, or as the main vocal style with softer, clean vocals used only to lighten some parts of a song, you're probably looking at at a substantially harder band.

Rough outline of the levels:

  1. As soft as rock gets. May be an otherwise 2 song without any guitar to distort, or a song which is generally slow and light.
  2. Soft rock. A lot of early rock is here; if you're not really sure if they're using an acoustic or an electric guitar, this is probably where you want to put it.
  3. Rock sans intensifier. A bit faster/louder/darker than 2, but still pretty soft. The heaviest soft rock and the softest hard rock can both be found here.
  4. Relatively harder rock. This is about where you can start finding punk, as well; lighter than this and you can't usually muster the kind of anger you need for punk. This is pretty much as heavy as Rock n' Roll got.
  5. Hard rock that is definitely still rock. The love songs start thinning out here, but lyrics at this stage can be about just about anything. The very softest of alt-metal can also get this low, but it is very rare.
  6. Difficult to tell if it's rock or metal. This is pretty much as far as you can get on just an acoustic guitar. Most Glam Metal and softer Post-Grunge can be found here. This is where you'll also find softer Alternative Metal.
  7. Classic metal and most Power Metal. After this point the number of punk bands begins to decrease, with the remaining examples predominantly of the hardcore punk variety. The music is pretty fast and noisy at this point. The lyrics start to become darker, though vocalists still use clean, melodic styles most of the time. The heavier sides of Glam and post-grunge can be found here as well as most Nu Metal. Viking and Folk metal starts showing up around here. The lightest Groove Metal can be found here.
  8. Most Thrash Metal, and heavier forms of Power Metal along with some classic metal. Lyrics are usually very dark at this point. Vocal style is usually a snarl, but clean singing is also common. Occasionally growls and screams will be employed. The harder side of hardcore punk is here, and Metalcore (fusion of thrash metal and hardcore punk) starts to predominate. Whether purists want to hear it or not, the lighter and more atmospheric side of Black Metal also starts here. You'll also find yet more viking/folk metal populating this region. Most Groove Metal is here. This is pretty much as heavy as you can get with radio airplay (with a few exceptions).
  9. Lighter Death Metal (especially Melodic Death Metal) or harder Thrash Metal. You'll also find a lot of the less abrasive 'true' Black Metal here. Here is about where you start to get singers growling or screaming for most of the song (This is also probably the highest level that can be attained with only clean singing). Lyrics may be very violent or just generally extremely dark. This is the last zone where you are likely to find hardcore punk that doesn't have a substantial metal or noise infusion. This is also about where Metalcore starts to transition to Deathcore (which also begins around this level). Most viking/folk metal that has a significant infusion of Black Metal or Death Metal falls here. A lot of the heavier side of Groove Metal is found here.
  10. Most Death Metal and Black Metal. Lyrics start to get positively disturbing and/or gorny and the singer will always be growling or screaming. The hardest variants of Thrash Metal, Melodic Death Metal, and viking/folk metal can hit this point, but that is quite uncommon. At this point hardcore bands become indistinguishable from metal to anyone who's not a loyal fan of both genres. Grindcore starts here. While it is possible for a metalcore band to get this high, it's very rare. Groove Metal at this level usually has a lot of Death Metal influence.
  11. Up to Eleven: Anal Cunt is here, along with the harder side of Grindcore especially the subgenres of pornogrind, noisegrind and goregrind. The most extreme Death Metal (a good portion of the brutal death metal and slam death metal subgenres end up up here) and Black Metal also lies here. The very heaviest mathcore (technical, chaotic hardcore) can also reach this level. Growling or screaming will start sounding almost inhuman, and often pitch-shifting or other computer-aided effects are used to drive the vocal range beyond what could normally be sustained during singing[2]). Significant elements of this class are experimental in nature, although Stealth Parodists commonly make their way up here as well.


  • A very well exemplified illustration of different levels of metal heads and the most stereotyped opinions.
  • Lower hardnesses are not bad. Remember, The Beatles come in at 2-3, and 10 (or above) can be unlistenable. Likewise, higher hardnesses are not bad. Remember that even though it may sound like impenetrable noise to you, that doesn't mean in principle it isn't enjoyable, nor that it doesn't contain real musical sophistication and talent.
  • As time goes on, those metal bands at the top of this chart go to increasingly insane lengths to top one another or themselves, which causes the chart to compress itself to accommodate the new hardness. So a 6 now could be a 4 or 5 ten years from now.
  • Level 11 exists in general for the placement of any music that is definitely harder or crazier than what is common at 10. While this may seem obvious, the important distinction to make is that anything at 11 should still exist within an easily identifiable genre, such that a familiar listener should easily be able to place it as Grindcore, Death Metal, Black Metal, or whatever genre it may draw from. What stops it from being a 10 is merely that it takes an additional step beyond what is popular in any given year within the 10 range of albums, either in terms of an increasingly raw, chaotic sound or in terms of sheer speed, or progressive technical brutality. In fact, one of the key and most helpful descriptors of level 11 is the word "crazier", which is often the way it sounds to most listeners until the style gains a bit of popularity and moves down into 10.
    • Corollarily, anything beyond 11 starts to become Noise. Noise is a category for unsortable experimental music that is extreme in ways other than being "heavy" in a traditional fashion. Anything by Merzbow, and most other Noise artists belongs here. There really are no identifiable guitars, basses, drums, or even vocals, and the music tends to become overwhelmed with extended techniques including computer sound manipulation. Here artists (and listeners) are mainly interested in exploring the limits of what can be interpreted musically, whereas at 11 listeners and musicians are merely interested in pushing the boundaries of existing genres. However, the genre-fucking mutability of things like Level 11 Grindcore tends to create ambiguity in this respect.
  • In general, a band will have songs that are higher or lower on the scale than their usual level, hence why websites like Wikipedia put some bands and/or albums as both rock and metal. (Compare "Tourette's" and "Polly", both by Nirvana.) It's easier to just judge each song by itself. You also have bands that change their style, often becoming heavier, softer, or becoming a genre that's much harder to classify altogether.
  • The reason some of the metal Fan Dumb hates power metal is that it is a rare exception to the above rule that metal bands tend to get harder over time.
  • Interestingly enough, a live performance, remix, or reissue of a song can actually be a different level than the original studio version, especially if an extended solo(s) or guest musicians are involved. Volume compression (which is frequent on recent remasters of old material) may arguably contribute to different hardnesses between releases as well.
  • Christian Metal is usually as heavy as its mainstream counterpart; however, in most cases, Christian metal lyrics aren't as dark as secular metal. So, a song could be a 10 or 11 in musical heaviness, while the lyrics could be about the power of God's love for the world. Obviously not all Christian metal songs are like this, but it's a common part of the genre, and the point still stands. As mentioned above, the lyrics are only indicators and don't play a direct part in the song's hardness, so you don't need to place Christian metal songs at a lower hardness just because of the lyrics.
    • Similarly, many of the more progressive, technical artists who reside at the hard end of the scale (Augury, Death, Neuraxis, and Cephalic Carnage, to name a few) generally write lyrics which, while certainly quite cynical, and darker than most at the soft end of the scale, aren't especially graphic or disturbing. Their lyrics are often highly philosophical, reflective, introspective, or merely less visceral as opposed to the outright Gorn written by many of the other bands residing at the top of the scale. Such exceptions also apply to bands such as Napalm Death and The Agonist which write politically or socially conscious lyrics.
  • Sometimes, songs with symphonic elements can be at a lower level of hardness than they would be without the symphonic elements. It depends on how the elements are implemented in the song, however; some more extreme artists use symphonic elements to provide a contrast between blast beats and the like, and manage to be just as heavy as other conventional death/black metal bands. Similarly folk elements work much the same way. Sorting these songs out on a case-by-case basis is the best solution.
  • Melodic tendencies can play a part in the song's hardness. Similar to the above note regarding symphonic elements, melody can decrease the hardness of a song, but it depends on how it's used, and as such the songs will be handled on a case-by-case basis.
  • Your Mileage May Vary: What's extreme to you may sound accessible, even catchy to the next person, so level assignments are highly subjective. For example, many tropers place metal ballads in level 6. On the other hand, seeing as how metal ballads typically interconnect softer acoustic/piano passages with harder electric guitar/percussion driven passages (that may otherwise reach into 8 to 9 range), one could just as easily assign them to level 7 or 8, depending on how far one felt certain passages removed the music from a level one felt was enjoyable. This is especially true in the case of progressive death metal, where extended symphonic, jazzy, proggish, or folkish passages are commonly interlaced with full-on level 10 blasting. Consider The Lair of Purity by Augury and The Lotus Eater by Opeth by way of example: are these songs brutalising extreme metal, or are they lighter and gentler progressive metal?
  • Even within each level, there are varying degrees of heaviness. For example, Voices of the Dead is definitely a heavier and more aggressive song than Nightmare. But "Nightmare," thanks in no small part to lines like "Your fucking NIGHTMARE!" and brief moments of Metalcore screaming, is ultimately heavy enough to be an 8. While "Voices Of The Dead" is ultimately too melodic for a 9.
Examples of Mohs Scale of Rock and Metal Hardness include:

Level 1

Level 2

Level 3

Level 4

Level 5

Level 6

Level 7

Level 8

Level 9

Level 10

Level 11

  1. where melody is usually quite complex, but is mostly deployed as a musical device rather than as a central element of composition
  2. (astoundingly though, not always
  3. Pretty hardcore for 1967.
  4. Would be bordering on 8 if not for the soft sections.
  5. If the instruments were any lighter, it would border on a 5 or 6.
  6. Ignore that bit at the beginning, obviously
  7. LP version
  8. The clean vocals before the bridge keep it from getting a 10.