Disturbed's fourth full-length offering announces its arrival with an air-raid siren. It's an appropriate gesture for the popular Chicago-based metal collective, whose rapid ascension from buzzed-about Ozzfest highlight to commercial hard rock juggernaut has been as divisive as it has been impressive. While Indestructible doesn't meddle with the melodic hard-hitting Pantera-inspired formula that fueled its predecessors, the dreaded nu-metal tag that followed the band out of the turn of the century seems wholly eradicated. If anything, Disturbed owe more to early-'90s Metallica and Brian Johnson-era AC/DC than they do Tool or Korn, as each staccato, tech-heavy riff is balanced out by some truly artful soloing and frontman David Draiman's mean and melodious pipes. Standout cuts like "Inside the Fire," "Deceiver, " "The Curse," and the skull-cracking title track, even though they could have appeared on any of the group's first three records, still manage to fire on every cylinder. Like its closest contemporary, Godsmack, this is a band that favors reliability over experimentation, and each piece of Indestructible, whether it's the pseudo-horror/fantasy artwork, the drop-D riffing, or the obligatory "shout-outs" in the liner notes to the purveyors of each member's gear endorsement deals, fits together like the world's most obvious puzzle. That said, there's a reason each of the group's previous albums bested the million mark, and with metal growing increasingly self-aware and divided between hardcore and hard rock, a new Disturbed record seems like a solid foundation on which to duke it out.