Machine Head: How do you create a masterpiece of modern metal? Is it a conscious effort on the part of the artists or is it something more organic - a confluence of events and moods, emotions and mechanics that all come together in the right place at the right time? That's the question that comes to mind upon the first listen to Machine Head's sixth studio album The Blackening. Guitars rip, drums pound, bass thunders and lyrics resonate as the Bay Area quartet soars past the bar set by its critically-lauded predecessor Through the Ashes of Empires. If Empires was the sounding of the trumpet, then The Blackening is the arrival of the hordes: dense, aggressive and inescapable.