Amazon.comStarting with 2001's Masses, an all-star effort featuring Matthew Shipp and a cast of downtown jazz luminaries, Spring Heel Jack's Ashley Wales and John Coxon have sculpted free-jazz source material into sometimes brilliant, but always interesting, sound collages. With Amassed, the duo use Shipp again, but lean heavily on European players like drummer Han Bennink and saxophonist Evan Parker, as well as guitarist Jason Pierce, leader of the space-rock band Spiritualized. The music is often surprisingly subdued and sometimes downright lovely--on "Lit," Kenny Wheeler plays a soulful trumpet over slowly shifting organ chords until the sound of a crumpling can finishes off the song. Things are their most cacophonous on "Duel," when Parker and Bennink go toe to toe as other sounds slowly move in and surround the two players, finally drowning them out for a time. Dynamic, imaginative, and overwhelming, Amassed defines this new fusion genre by realizing many of the possibilities of both electronic production advances and avant-garde jazz. --Tad Hendrickson