Pianist Marilyn Crispell attracted an initial following with a full-fisted attack, dense tone clusters, and bold dissonances inspired by Cecil Taylor, later refining her style during a ten-year stint with Anthony Braxton. She brought her audience along with her and enlarged it when she signed with ECM in 1996, steadily revealing her lyrical and contemplative sensibilities. Through these 13 riveting improvised duets with clarinetist David Rothenberg, Crispell takes a spacious, reflective approach. On several tracks she delves into contemporary-music techniques by plucking and striking the piano’s soundboard, extrapolating its percussive essence. Both she and Rothenberg, the author of Why Birds Sing and Thousand Mile Song (about making music with whales), come up with fresh melodic lines and fragmented conversations that can leave you breathless or bewildered. Rothenberg studied with clarinet masters Jimmy Giuffre and Joe Maneri, and his mastery of both the conventional and the bass clarinet begets gorgeous musical timbres, especially in the lower ranges, that dovetail exquisitely with Crispell’s perfectly etched notes and ghostly soundboard scratchings. Only a few tracks will accelerate your pulse, but absorbing this duo’s expansive moments will hold you entranced in evocative mystery.