Airs Tuesday, June 18 at 9 p.m. Here's a pairing that raises the question: "Why hasn't this happened before?" The Bad Plus have been a revisionist cover band and today mostly make original piano trio music. Bill Frisell is the quintessential jazz collaborator. The guitarist, making the second of three appearances at this year's Newport Jazz Festival, is down for anything involving good musicians, and can be counted on to execute it well. Together, they paid tribute to one of their mutual heroes, the late drummer Paul Motian, in a set comprised mostly of his haunting compositions. The band features Ethan Iverson on piano, Reid Anderson on bass, Dave King on drums and Bill Frisell on guitar.