Scott Herren has been crafting mostly instrumental hip-hop under the Prefuse 73 moniker since the project’s impressive 2001 debut, Vocal Studies + Uprock Narratives. (Herren also releases work as Savath & Savalas and Delarosa & Asora.) Preparations pretty much sticks to the terrain of earlier Prefuse 73 releases. Funky, mid-tempo grooves chug along with dazzling aural confections strapped to their backs: crystalline tones, animated noise bursts, looped strings, and all sorts of ever-shifting sonic shrubbery. It’s easy to pick out the standout piece on Preparations: “The Class of 73 Bells” is the sort of entrancing cut that makes you play it again and again. The overlapping vocals of Claudia and Alejandra Deheza, the twin sisters who front School of Seven Bells, are irresistible. The brief interlude, “Aborted Hugs,” fascinates with its mix of tangled dissonance and sense of mellow glide, and Preparations ends strongly with “Preparation Outro Version,” a tense and simmering closer rife with evocative sound effects. A bonus disc, Interregnums, displays Herren’s beatless, orchestral soundtrack-y side.