Like a cloud-flecked summer sky, Steve Reich’s Music for 18 Musicians is both beautiful and subject to inexorable change. The work, composed in the 1970s, is based on cycles or “pulses” of 11 chords, which shimmer and change tone color across multiple repetitions and transformations. It achieved cult status following the 1978 release of its premiere recording, a flawless album set down as a single track by the Steve Reich Ensemble. David Bowie and Brian Eno were among its most ardent fans. There’s an expansive, seemingly infinite spiritual depth to the piece. This remarkably intense performance of it, heightened by ECM’s recorded sound and the lively interaction between the voices and diverse instruments, subverts the minimalist tag so routinely attached to Reich’s music.