Amazon.comDavid Grubbs first recorded with teenaged Louisville punks Squirrel Bait and came to prominence exploring the intersections of pop, art, and rock music with Gastr Del Sol. Swedish saxophonist Mats Gustafsson has toured the U.S. with MacArthur Award-winning jazz man Ken Vandermark and Dutch sound poet Jaap Blonk. The fact that this duet recording combines two rarely joined genres, minimalism and free improvisation, isn't as surprising as the finely etched beauty of its performances. The 65-minute-long CD is divided into two parts. For each Gustafsson plays tenor saxophone and fluteophone (an instrument that he invented by jamming an alto saxophone's mouthpiece into a flute), using circular breathing to blow seemingly endless microtonal sound streams over the undulating drones that Grubbs squeezes from his harmonium (an archaic hand-pumped reed organ). Both pieces proceed so slowly that one's ears inevitably become attuned to minute variations of pitch; once that occurs, it's impossible to avoid being hypnotized by the music's glacial evolution. --Bill Meyer