New attitude?

But Pantera, who make no bones about serving up the most straightforward thrash-metal of the decade, are the exception to the rule -- elsewhere, metal is awakening with an identity crisis. The genre's founding fathers seem eager to leave the fold -- Metallica, for one, have hit the mainstream running. And now that Slayer have recorded an album of hardcore punk covers, Undisputed Attitude (American), they've declared themselves a "punk band," which is sorta like the guy in the park who thinks he's Abe Lincoln because he can recite the Gettysburg Address. What's more, hardcore-influenced bands like New York's Biohazard (whose new Mata Leão is due from Warner Bros. on June 11) are drawing much larger audiences, bringing a heritage of no-frills, politically charged bombast to bear on metal's evolving sphere.

Pantera haven't changed their formula significantly since their 1990 debut, Cowboys from Hell: a chiseled, razor-edged, antiseptic shredding accentuated with flashy harmonic sustain leads -- simultaneously clean and dirty, with Phil Anselmo's rabid growl hovering between Hank Rollins and Napalm Death. If they've never varied much from that formula, they've at least honed it to relative perfection, cutting the guitars even more obliquely, straining to maintain a melodic balance. On Trendkill they've broadened the thrash formula beyond where anyone was willing to take it five or six years ago. There's a genuinely haunting, darkly melodic sensibility on "10's," a cinematic industrial interlude tucked into "Living Through Me" -- and "Suicide Note Pt. I" ends up sounding like the bastard spawn of Alice in Chains and folk/bluesman Chris Smither. The sheer noise quotient is amplified by the addition of Seth Putnam of Boston's Anal Cunt, who lends his distinctive screaming dry heave to the heavier tracks (Anselmo returns the favor on Anal Cunt's far nobler 40 More Reasons To Hate Us).

The lyrics, on the other hand, are still mostly forgettable. Suicide and self-loathing figure in about half the songs; the rest involve hating other people. Seldom has boy-angst gotten any less subtle than "Expect the worse [sic] you bleeding heart, but kill me first before it starts/Yes, my cock is getting hard; we are born different after all." Who says there's no sex in your violence?

Slayer's Undisputed Attitude (American) -- featuring covers of Minor Threat, Verbal Abuse, DI,DRI, and TSOL, plus a few Hell Awaits-era outtakes and a new song about the Gemini killer -- is ultimately no better or worse than, say, Guns N' Roses' The Spaghetti Incident, Metallica's Garage Days Re-Revisited, or Megadeth's cover of "Anarchy in the UK." Played at Flight of the Bumblebee buzzsaw speed with a distinctive, finite thrash edge, Attitude proves metal has plenty to gain by stealing the simplicity and angular tunefulness of hardcore. The Minor Threat tunes may sound a bit surreal in this context, but Verbal Abuse's "I Hate You," for instance, makes a powerful, concise Slayer song. Sure, Slayer add guitar solos and change the lyrics where they don't like (or can't figure out) the originals, even going so far as to bastardize the Stooges' proto-punk masterpiece "I Wanna Be Your Dog" into "I'm Gonna Be Your God." But the metal bands' co-opting of punk has always been viewed as sacrilege by hardcore purists, so to that extent, Slayer are just slaughtering yet another sacred cow.

What with Slayer's horror schlock and Pantera's nuevo-cock-thrash, you can see why the earnest, politically astute lads in Biohazard (who play Axis this Friday) would want no part of getting lumped in with metal. Their fourth album, Mata Leão, is powered by guitar churn overdriven into a crackling, fuzzed fury that backs away from the chunkier, metallized riffing of their earlier efforts. With the under-two-minute blasts "Competition" and "A Lot To Learn," they return to roots-hardcore simplicity: pick four chords, pull out all the stops, and splice in break-time tempo changes from head-bobbin' to down-the-stretch gallop.

What's more compelling, though, is the way, on songs like "Control," they weave sharply-timed repetitive guitar and vocal phrases into a bare-bones riff, cultivate a gnarly texture, and exhibit greater instrumental restraint. Rage Against the Machine might cross rap with rock and ride the shock wave as the two collide, but Biohazard have integrated hip-hop's lessons into a distinctively urban, astringent narrative. Is it heavy metal? Maybe not, but it's the kind of voice metal could benefit from hearing.