Aftertaste and the Rollins Band's Come In and Burn are prime examples of the '90s brand of paramilitary headbanging. With their drillsergeant demeanors and drill-press riffs, the Rollins Band and Helmet typify this Spartan approach to hard rock: Singer Henry Rollins helped shape the sound with Black Flag, a loud-fast Southern California punk band that had mutated into a metal juggernaut by the time of its demise, in 1986. On Come In and Burn, its seventh album, Rollins' namesake band continues to build on the Flag's foundation with an elastic, almost jazzlike approach to metallic blues.

In contrast, Helmet emerged out of New York in the late '80s with a tight, taut sound that bridged the gap between thrash metal and the art-damaged vocabulary of Lower East Side guitar innovators such as Glenn Branca and the Band of Susans, both of whom employed Helmet founding member Page Hamilton. On Aftertaste, their fourth album, Helmet return to those take-no-prisoners roots after dabbling in some bluesy detours on their 1994 release, Betty, and experimenting with hip-hoppers House of Pain on the Judgment Night soundtrack.

Though neither the Rollins Band nor Helmet will likely be sitting in with Ornette Coleman any time soon, they bring a jazz ensemble's sense of interplay to the heavy-lifting routines of metal. They also feature guitarists who, like Rage Against the Machine's Tom Morello and the Jesus Lizard's Duane Denison, are demonstrating that the instrument still belongs on the cutting edge in these trip-hop-happy times.

On Come In and Burn, Chris Haskett's guitar engages in an agitated dialogue with Melvin Gibbs' bass and Sim Cain's drums, and the loud-to-quiet dynamics and roller-coaster tempos suggest a trio whose members are responding to one another on the fly rather than adhering to a carefully structured arrangement. Gibbs frequently drives the melodies with bulldozer riffs, notably on "During a City" and "Thursday Afternoon," freeing Haskett to create his own vocabulary of guitar sounds: an ambulance siren, a circling vulture, a damaged garbage disposal.

Texture – not the number of notes played – is what counts; one of Come In and Burn's most exciting moments is the guitar break on "Spilling Over the Side," in which Haskett shapes a funnel cloud of white noise with a handful of chords. Another