In roughly a decade as one of the biggest names on the New York underground hip-hop label Definitive Jux, Aesop Rock developed a distinctive style, as well as a solid support base to back it up. But after operations at Definitive Jux were put on an "indefinite hiatus" in 2010, he hung his hat at Minneapolis' Rhymesayers label. Putting together his forthcoming album Skelethon on a new label five years after its predecessor would have been a daunting enough task, but Aesop Rock also decided to forgo the assistance of his go-to producer, Blockhead, making this his first fully self-produced effort. In light of all of these changes, "Zero Dark Thirty" finds him wisely deciding to tread familiar territory: dense, buzzing beats peppered with snippets of live instruments, coupled with his usual verbose wordplay.
Much of what makes Aesop Rock's delivery so compelling in "Zero Dark Thirty" — and in most of his past work — comes from his focus on the intricate details of his own voice. He has a knack for taking plosive sounds and making them especially sharp and percussive; he often sounds like he's trying to spit syllables across the room as they leave his mouth. He plays this against the low, raspy tone of his voice to toy with the timing of his delivery. Slight changes in his phrasing can make it sound as if he's drifting slightly out of step, until he snaps back in line with a flurry of hard consonants realigned with the beat. It's a clever trick that lends his words a propulsive quality.
Aesop Rock's lyrics are always dense and frequently rife with pessimism and paranoia. "Zero Dark Thirty" is no exception, painting a bleak future with a chorus of, "In the terrifying face of a future tongue / down from a huntable surplus to one." Like former Definitive Jux labelmate El-P, Aesop Rock sees dark days on the horizon, but he doesn't think that should interfere with making a killer beat. The way he sees it, we should at least be able to nod our heads in time as the world crumbles around us.