Within the pantheon of guitar pedals, there is no shortage of legendary dirt options. Here, the venerable Tubescreamer, OCD, and Rat have all been in the top spots for decades, champions of great tone across the entire gear world.

But every Mount Olympus has its Hades, the dark and brooding antagonist confined to its underground kingdom.

In this realm of drives and distortions, there is no better candidate for chthonic overlord than the Boss HM-2 Heavy Metal. Its intense, atmospheric grind runs perpendicular to the prevailing ideas of what constitutes a “good” guitar tone.

And while it may be nowhere nearly as pleasant or ubiquitous as the Rat, Big Muff, or even other Boss distortions, the HM-2 has had an undeniable impact on the world of heavy guitar tone.

Maxed Out Tone

The HM-2 is a truly unique beast with a tone that is almost more fuzz than it is true distortion. It has a bite and an EQ characteristic unlike that of any other dirt pedal on or off the market. The Color Mix controls – low and high – are incredibly sensitive, offering +/-20dB boost/cut at their respective frequencies.

The Distortion control, on the other hand, is almost completely useless. Adjusting the knob between about eight and three o’clock doesn’t actually result in any change in gain. Even outside of that considerable dead spot, the range is limited.

That alone could render any other pedal practically useless. But the HM-2 has nearly built its entire legacy from one setting: everything dimed.

This analysis from Atomium Amps breaks down what makes the HM-2 work so well when cranked to 10:

"Aside from the insane amount of boost from both the level and EQ pushing the amp much harder, the “suspension bridge” curve does a couple of things. First, notice how the low peak is sitting right on the fundamental of the low E string of the guitar. So the chugga-chugga stuff is going to have a lot of impact at its lowest. Then, there’s a huge dip in the midbass, centered at ~240Hz, which is the stuff that most people hear as “mud.” The high peak boosts the vocal midrange, which at this stage is mostly comprised of odd-order harmonics emphasizing ‘crunch’ (fifths, in large part). It’s the ultimate angry power-chord generator."

The result of all that is a distortion that sounds like a chainsaw ripping into an angry beehive in the best way possible. Appropriately, this tone became known as the buzzsaw, and its maxed out sound and philosophy became integral to the evolution of extreme music.

Early History

Unlike many other iconic drive pedals, the HM-2 was only on the market for a handful of years. It was first produced in Japan from 1983-1988 and then in Taiwan before being discontinued in 1991.

For the majority of its eight years in production, the HM-2 went along largely unrecognized and underappreciated. Though initially designed as an emulation of a Marshall stack and marketed toward the hair metallers of the mid-’80s, these players continued to favor actual Marshall stacks and emerging high-gain tube amps in lieu of a stompbox.

One of the few bits of recognition the HM-2 received in these early years came from an unlikely evangelist: Pink Floyd’s David Gilmour. On the surface, the trademark harsh grind of the HM-2 may seem like the antithesis of the immaculate tone Gilmour is famous for. But paired with a Mesa Boogie Mark I head, it became a staple of his sound in the ‘80s on work like About Face and A Momentary Lapse of Reason.

Gilmour broke down how he wrangled this beast in an 1984 issue of Guitar Player Magazine saying,

"At the moment, the sound that I'm using a lot of the time is going through a Boss HM-2 Heavy Metal to a Boogie amplifier to a [MXR] DDL and then on into a regular Fender amplifier....I use a DDL on it...because I find it stops the fuzz box from from sounding like a fuzz box. It smoothes off the unpleasant, raw frequencies that you get from the fuzz box. Then you get a nice sort of sound.”

While Gilmour’s use of the HM-2 may have inspired some of the fanatics trying to cop his tone to pick one up, it was still a far cry from the exposure the pedal would need in order to have a lasting impact.

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Defining Heaviness

The HM-2 might not have ever reached cult status within the metal world without Swedish metal band Entombed’s 1990 debut album, Left Hand Path. In searching for tones while writing and recording demos in the late ‘80s, the young guitarists of Entombed (then called Nihilist) stumbled upon the iconic buzzsaw sound of a dimed HM-2 and knew they had found something special.

Armed with nothing but cheap amps and cheaper axes, guitarists Leif Cuzner, Alex Hellid, and Uffe Cederlund leaned heavily on the grinding distortion of the HM-2. Paired with their aggressive songwriting, the band carved out a sound distinct from the established American Death Metal sound of the time.

Cederlund summed up the simplicity of the guitar tone on Path stating, “I just used a worthless Ibanez guitar, a small Peavey combo amplifier, and a Boss Heavy Metal pedal. Basically, there are two Boss Heavy Metal-distorted guitars – one in each speaker – and a DS-1 in the middle.” This became the basis for the tone which defined the visceral sound of their early albums and went on to truly define the sound of Swedish Death Metal as a whole.

I just used a worthless Ibanez guitar, a small Peavey combo amplifier, and a Boss Heavy Metal pedal." —Uffe Cederlund

Entombed’s producer on Left Hand Path, Tomas Skogsberg, took the HM-2 and championed it within the community of bands that recorded at his Sunlight Studios in Stockholm, which included other Swedish Death Metal pioneers like Dismember, Carange, and Grotesque.

The buzzsaw sound from these recordings spread like wildfire, moving beyond the tight-knit death metal community of Stockholm to other bands in Scandinavia and to the global metal community of the early ‘90s.

As the pedal spread beyond Stockholm, the way it was used in the context of metal tone evolved, too. An increasingly common use for the HM-2 was as a boost running into an overdriven amp – often a Marshall JCM 800 or even another distortion pedal.

Gothenburg’s At The Gates used this technique to great effect on their landmark album, Slaughter of the Soul, running an HM-2 as a boost into Boss MT-2 Metalzone and then into a solid state Peavey amp. This maintained much of the color of the HM-2, while also allowing for tighter, more articulate high gain tone.

The HM-2 Today

Recent years have seen a resurgence and a continued evolution of the HM-2’s use in metal. Bands drawing influence from Entombed’s early work in combination with various strains of death metal, grindcore, hardcore, and sludge have reached to the HM-2 for it’s gnarly, biting distortion.

Paired with modern production techniques, this pedal has contributed to some of the heaviest records of the new millennium."

Much in the way that the early influence of the buzzsaw sound came from the work of producer Tomas Skogsberg, many of today’s HM-2 laden records are coming from GodCity Studios, headed by producer Kurt Ballou.

Ballou’s work with bands like Nails, Black Breath, Trap Them, and Harm’s Way has brought this obscure ‘80s pedal to prominence in metal guitar tone. Paired with modern production techniques, this pedal has contributed to some of the heaviest records of the new millennium.

This revival has, in turn, spawned a number of clones that emulate and build upon the HM-2’s trademark sound. Boutique builders like Lone Wolf Audio, Wren and Cuff, Abominable Electronics, Dunwich Amps, BYOC, and most recently, Walrus Audio all have their own takes on approximating the original, each with various mods to take the grind to new heights.

For a deeper look all the places the HM-2 has appeared in recordings and performances, check out Geoffroy Lagrange's piece on this classic pedal.

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