The only problem with Ugly Duckling's delightful Journey To Anywhere and Taste The Secret is that they're almost too slick and catchy, boasting shimmering surfaces so immediately infectious that they seem to preclude any depth. But excessive slickness isn't a problem with Crankcase's Model Arithmetic, an endearingly lo-fi album that pairs retro-minded Ugly Duckling rapper Andy Cooper, a.k.a. "Andycat," with an equally retro-minded live funk band. Alas, the boyishly charming Andycat doesn't rap over all of the 11 tracks, and his presence is sorely missed on the instrumentals. Without a vocal presence, Crankcase is simply a good funk band that smartly works the occasional left-field sample into its greasy grooves. With Andycat serving as master of ceremonies, however, the group becomes much more interesting, a charmingly ramshackle experiment that's at once retro and innovative. Model Arithmetic's best songs recall the conceptual smarts and True School aesthetic of its leader's main gig. On "Sam's The Man," Andycat replaces the obligatory tribute to the DJ with an equally affectionate tribute to Crankcase's bass player. "The Weed Song," meanwhile, gently sends up rap music's obsession with Cheech and Chong's muse by scolding pretentious stoners who turn into amateur philosophers under the influence of the demon weed. Crankcase saves its best for last on the album-closing single "The Tale Of The Stolen Funk And How We Stole It Back," in which Andycat avenges the scourge of rap-rock by replacing rap-rockers onstage, then shaving off the Korn wannabes' goatees and ripping off their wallet chains and baseball caps. When he's rocking the mic, at least, he leads by example, showing the Fred Durst contingent that there's a smarter, more enjoyable way to blend rap with live instrumentation.