LADYSMITH BLACK MAMBAZO: "No Boundaries" (Heads Up) This long-standing South African vocal group, best-known to casual listeners for stellar work on Paul Simon's "Graceland," have been on a creative roll recently. Last year's album of spirituals, "Raise Your Spirit Higher," copped two Grammy nominations and now comes this collaboration with the English Chamber Orchestra on a set that combines their trademark "tiptoe" vocals with classical compositions from Bach, Mozart and Schubert. It's an ambitious undertaking, but the execution is flawless and the results are simply gorgeous. The group's rousing take on the ancient prayer "Dona Nobis Pacem" should put them in the Grammy winner's circle next year. Ladysmith performs at UCLA's Royce Hall on Feb. 12.