Only in metal do certain sonic techniques seem to spawn entire subgenres. Whether it’s accordion in melodeath or onomatopoeic palm-muting spurring forward the new age of brickwall mastering, metal hasn’t shied away from many of the oddest-seeming musical tools (or gimmicks). Strangely enough, though, metal still lacks widespread improvisation.

On the surface, it seems like improv is more or less incompatible with metal. Grindcore, black metal, and death metal don’t leave much room for spontaneity, especially when they're travelling at tempos in excess of 200 BPM. Sludge metal, doom and post-metal face the issue of having too much space. Power metal, prog, melodeath, and heavy metal often tell stories – and usually keep the narrative pretty consistent from rendition to rendition. Improvising vs. composing is like talking vs. writing, some might say, and metal is all essays.

On the other hand, even metal in its mainstream forms is surprisingly flexible. Those qualities that might seem to discourage improv in metal - concerns about speed, aggression, flavor - can easily be flipped on their heads and viewed as qualities that lend themselves as well to improvisation as they do to circle pits and unreadable logos.

History matters too. Performance, in its inherent spontaneity, can be considered an extension of improv. Take classical music - a field that metal has historically borrowed from, which is rooted in strictly defined repertoire, and to which performance is its most central component. Living composers exist, for sure, but ultimately, quality is assessed by an artist’s unique interpretation of a pre-written piece. If you think about performance this way, improvisation makes more sense in the context of metal; of course no two performances will be the same even if you’re midi-triggering noise gates and routing two thirds of your band through MacBooks.

Moreover, much of the band-based music that metal is rooted in had a heavy focus on improvisation, both free and melodic. It’s also fair to argue that composition is, at its most basic level, is derived from improv. After all, ideas come to you from somewhere; there’s no conceivable way to compose music entirely devoid of spontaneity.

Still, metal’s general dearth of improv needs explaining. Some of the factors are more obvious than others, like the convenience and accessibility possessed by non-improvisational music. From a listener’s perspective, songs that one can expect to sound consistently the same resonate better - people love recognizing things, even breakdowns. Many fans like hearing on-the-spot content live, but just as many (if not more) musicians and fans prefer hearing the thing as it sounds on record.

It’s also far easier for a musician to toil for hours writing, perfecting and memorizing a piece of music than it is to bust out genius on the fly, especially for self-taught musicians. Most metal guys aren’t formally trained, and instead grew up learning their favorite songs in their bedrooms through 10-watt practice amps.

Again, in subgenres like tech-death, where flashy displays of proficiency are viewed as the end-all be-all, the organic nature of performance has been removed by the process of narrowing in on and neurotically perfecting both compositions and recordings. Accordingly, these are often the kinds of music that translate the least well from record to live.

Despite the fact that improvisation hasn’t become a prominent part of the metal canon, there still have been metal bands and musicians that have toyed with, or even wholly embraced, the technique:

Black Sabbath

Plenty of blues and prog-based metal bands improvised, but not freely - they played fairly "in the box" jams that have about as much in common with Phish as with Fister. Even though there will always be a place in my heart for a kushed-out stoner rock jam, much of that kind of improvisation can often feel formulaic even if you’re watching it live. (Also of note: live, Swans often employ a similar style of jamming where riffs are extended and expanded à la Led Zeppelin).


Here we go – music that “sounds” much more freely improvised in the purest alignment with a general stereotype. Encenathrakh is also one of the least accessible bands on this list, and while there’s undoubtedly a lot of brilliance in the band’s playing, you’d be hard-pressed to find even a metal listener who isn’t initially put off by the lack of conventional musicality in these recordings. In other words, this music is at the opposite end of the spectrum from the aforementioned bluesy jams – it “sounds” improvised, technical, and impressive, but it doesn’t sound particularly musical.


I have always found In Umbra kind of intolerable. That’s probably intentional, given the band’s fascination with both aural and physical torture, and the sheer nature of a 64-minute-long one-take album. But while impressive, Abruptum’s freely improvised recordings still aren’t accessible in any regard.


As vocalist Doug Moore puts it, "[Pyrrhon use] improvisation to inject unpredictability into our songs . . . there's really no harmonic constraints on what we can do during those sections, though we generally try to retain the feel of the larger song. Improvisation also allows the songs to 'live' a little more — improvising means that we engage with each song in a new and unique way during each performance, rather than just following a rote script.

You can hear that unpredictability in the recorded version of "Eternity in a Breath," which Moore says "will never sound quite the way it does on this recording again." Pyrrhon is pretty far off the grid, to be sure, but the music isn’t structureless or wholly without repetition. Instead, the band’s seamless improvisations stray just far enough from the spirit of their compositions to add flavor while still dialing up the intensity.


Mastery’s 2015 full-length Valis is composed of sole member Ephemeral Domignostika’s jams translated into recordings. In the same way that Domignostika inverts the traditional creative process - play first, write later - Mastery’s music upends most conventions of songwriting, eschewing harmonic and rhythmic accord in a way that makes timbre & tone tumble over one another like a kvlt version of The Dillinger Escape Plan. It’s certainly not accessible, but it’s an extremely novel blend of improvisation and more structured composition.

The Mars Volta

The Mars Volta is quite likely the most famous example of a metal band that’s utilized improv in significant amounts. Sometimes totally free, sometimes structured, The Mars Volta incorporated improv side-by-side with composition.

Unlike most of the other acts on this list, though, The Mars Volta utilized both free-form and melodic forms of improvisation. There are melodic elements in some of the above artists’ music, sure, but most of these bands lean strongly towards atonality and extended technique. Metal hasn’t had a great melodic improviser since… well, maybe ever, and that’s strange considering how big of a role melodic improvisation has played in blues.


The point of this article isn’t to suggest that bands should see improv as an end-all be-all, though. Plenty of metal just doesn’t call for excessive looseness, spontaneity or even flavor. However, musicians shouldn’t remain apprehensive or ignorant of improv, given its potential to strengthen music without diluting its core.

In the words of Colin Marston, "music is just good or it isn’t whether or not it takes 10 years to write or 0 seconds. What’s interesting to me is that the extremes of composed music and improv actually meet sometimes and can sound indistinguishable." It might be impossible to accurately judge the prevalence of improv in metal, but I’m confident that improv - both free and melodic - can find its place in the canon too.

—Mark Moritz-Rabson

Thanks to Doug Moore, Greg Fox, & Thomas Pridgen for taking the time to talk to IO.

Note: an earlier version of this article misstated that Ocrilim's recordings were improvised. The article has been edited to reflect this change.