Sepultura's sixth album begins and ends with the sound of crickets. Aside from the short instrumental "Leaf," it's the only tranquility on an otherwise chaotic disc. Like many thrash-metal artists, Sepultura play a violent game of sonic overload. But rather than whip itself into paroxysms of directionless rage as it did in its early years, the band uses its catharsis as a creative force, funneling torrents of noise into a tunnel of hate.

Sepultura have learned the speed-metal rules well enough to bend them into something new. Instead of playing monolithic guitar riffs, they rely on blunt, percussive rhythms that echo like war-zone mortar blasts. And in lieu of twiddly guitar solos, the band opts for oppressive effects and screaming feedback. Brazilian percussionist Carlinhos Brown makes a guest appearance, providing the groove for "Ratamahatta" (sung mostly in Portuguese), and several songs on Roots are enhanced with recordings of the Xavantes Indians in the jungles of Brazil. On "Itsári," foreboding acoustic strums are layered over primitive beats and war chants, conjuring visions of impending doom.

Roots shows Sepultura acknowledging their Brazilian heritage after years of trying to assimilate North American culture. "Ambush" is about the environmental activist Chico Mendes, who was killed while trying to save the rain forest, and "Dictatorshit" is a condemnation of military juntas. But Roots is also a vitriolic tirade prompted by pain and betrayal. During the past two years, Sepultura have parted ways with their former label, Epic, and frontman Max Cavalera has faced discrimination from the police because of his heavy-metal looks. Sepultura seek retribution through hostile and sometimes juvenile lyrics.

Like the Sex Pistols' "EMI," "Cut Throat" attacks corporate rock for being greedy and narrow-minded: "Money isn't our god/Integrity will free our soul from Enslavement/Pathetic/Ignorant/Corporate" (note the acronym for Epic). Elsewhere, "Attitude" lambastes complacency and ignorance: "What were you thinking?/What a wonderful world?/You're full of shit." But it's "Born Stubborn" that reveals the group's modus operandi: "We live without rules/Tear down the walls that try to hold us." Sure enough, Roots is a refreshing step forward in a genre full of bands that are creatively bankrupt. (RS 730)

JON WIEDERHORN