In selecting material for ECM"s :rarum anthology series, which is programmed by the artists, the surviving members of the Art Ensemble of Chicago may have had trouble finding or fitting representative pieces. One song is from a 1981 solo effort by the late trumpeter Lester Bowie, another from a 1997 album by saxophonist Roscoe Mitchell. The sole track from the Art Ensemble"s terrific double-live Urban Bushmen seems to have been chosen for its brevity. But if this single-disc collection doesn"t make the most convincing argument for the strength and consistency of the legendary avant-gardists during their sometimes underrated stay with ECM, two cuts from Full Force open and close the case for their power and reach: Bowie"s pungent, propulsive, plunger-muting "Charlie M" and bassist Malachi Favors"s nearly 20-minute long, phase-shifting "Magg Zelma," which ranges from percussive walls of sound to heated horn solos. This label was the first to properly record the Art Ensemble. That achievement is enhanced by ECM"s first foray into 24-bit/96kHz remasterings. --Lloyd Sachs