Music writers are suckers for geography. Tying up groups of bands in neat little localized bows makes for easy copy, with the added benefit that once you pigeonhole a bunch of quasi-related groups — the “Seattle Sound,” say — you have that touchstone to deploy next time you feel like phoning in some cheap comparisons.

Seattle bands are the order of the day today, though the comparisons will hopefully be hewn from finer stuff. Specifically, two Seattle bands that have recently released new records: The Melvins, and Black Breath.

Black Breath – “Children of the Horn”

The traditional route here would be to slap these two groups down side by side and make a bunch of comparisons — to bands they both sound like, or to the way the weather in Seattle (rainy, natch) informs their interpollinated styles. In this case, that’s totally impossible. Though they both fall under the general aegis of metal, and play music that is down-tuned, loud, and heavy, the similarities end there. When you put Black Breath and The Melvins side-by-side, all you see is contrasts.

For one thing, The Melvins are roughly six times older. Formed in the early 80’s, the band is now something of a hard rock institution, weathering a generation of music and still out-rocking many of the bands they influenced. A pre-Nirvana Kurt Cobain famously auditioned on guitar, but botched it — a bad case of nerves made him temporarily forget all the songs. Though generally a trio, in 2006 the band absorbed both members of the cult metal duo Big Business, taking the stage with two drummers (right- and left-handed) and a bolstered vocal attack.

Though the music is still built around muscular, inventive drumming and guitarist Buzz Osbourne’s bottom-heavy riffs, the band’s maturation has seen them become increasingly digressive. More and more, they flex their musical muscle during wild excursions into the bizarre and sometimes borderline self-indulgent outer reaches. New release The Bride Screamed Murder features some plutonium-heavy sections that recall the band’s classic material, along with the ever-listenable percussion prowess of drummers Dale Crover and Jared Coady, but it’s hard to wrap your mind around the drill sergeant chanting in “The Water Glass,” the squeaky balloon solo at the end of “Hospital Up,” or the impressionistic “My Generation” cover.

Not that anyone seems to mind. Maybe it’s the fact that this grab-bag songwriting tendency has always been a part of The Melvins’ sound. What’s clear is that the band have earned the right to do whatever they want. Their idiosyncrasy even garnered a recent accolade; the new LP snuck into last week’s Billboard 200 chart in the final, 200th spot.

Black Breath have a much shorter history, but came charging out of the blocks after forming in 2005. Snatched up by the perennially taste-making doom label Southern Lord Records, the band released incendiary EP Razor to Oblivion in 2009, which won critical acclaim from all quarters. They then hunkered down to craft a full-length follow-up.

The Melvins – “The Water Glass”

Taut, speedy, and efficient, the quintet’s music is antithetical to The Melvins’ expansive, versatile approach. Fusing vintage thrash with primal black metal, old-school Swedish death metal, and classic crust punk, the youthful group most closely resemble death legends Entombed, churning out three-to-four minute salvos of snarling, fuzzy invective, boasting hardcore’s intensity and metal’s airtight musicianship.

New album Heavy Breathing rages from back to front, starting with the tremolo-picked statement of purpose that begins “Black Sin (Spit on the Cross)” and continuing full-throttle until the epic midtempo lead that concludes “WeWhoCannotBeNamed.” The production by Converge‘s Kurt Ballou is impeccable, further cementing his bona fides as modern metal’s master of guitar tone.

Listening to the two records back to back, you hear two bands — each immensely talented in their own way — at opposite ends of the career spectrum. The Melvins are legendary, and owe explanations to no one. Their fans may even appear in the comments below, to excoriate me for my tepid reaction to their new record. They’ve had the time to become the band they want to be, making music in a manner that’s unique and immediately recognizable. They don’t sound like anyone, except themselves.

For all Black Breath’s ability, they still wear their influences on their sleeves. Maybe they always will. If they’re content with sounding like the best band that never made it out of Malmo in ’93, they’ll hear nothing but praise from me. Slot them into a playlist next to the Melvins, though, and it makes you think about how these things shake out in the long term. New, unknown bands win fans and influence by appealing to tendencies and tastes that already exist, synthesizing and reformulating chosen elements of their musical ancestors. Over time, they cease to be a collection of influences and grow into themselves.

The Melvins and Black Breath represent the extremities of this progression. Both of their new records make great listening, as do their live shows. But even though they’re both from Seattle, they couldn’t be more different.