Groups like the Bad Plus have made jazz covers cool again — maybe because one senses a true love for rock, not just its crossover potential. On their sixth CD, the inventive Minneapolis trio court disaster by adding a vocalist. Thankfully, she's Wendy Lewis, an indie-rock vet who floats Kurt Cobain's numbed equivocations over a capsizing groove here on "Lithium" and even nails that bone-chilling scream. It's one of the few credible Nirvana covers ever. The crew also finds Wilco's "Radio Cure" and mad rhythms in a piece by classical composer Milton Babbitt — it's about as badass as highbrow gets.