The Roots' human beatbox has been wowing listeners with his bag of vocal tricks since he debuted on the band's Illadelph Halflife; whether offering an amazing simulation of a DJ working a pair of turntables or adding even farther-out effects, he's become a deserved showstopper. But the gymnastic beatboxing and faux-scratching would merely make his first solo album a one-listen novelty, if he hadn't surrounded them with tunes worth hearing more than twice. Luckily, on the majority of this debut, Scratch is able to do just that, especially when he teams with fellow Philadelphian Bilal for the Prince-like stomp of"Square One" and pumps up the pulsing"That's What We Talkin' About" with an authentic brass section. The album's flaw is a common one to the hip-hop genre: too many guest MCs (there are 20-odd vocalists credited). And most of the rhymers Scratch enlists aren't up to the level of his bandmates Malik B and Black Thought, who enliven the very Rootsy"U Know the Rulez." But on the whole, The Embodiment of Instrumentation offers more than just the expected"oohs" and"ahs."