Though it's often prone to sounding like a malfunctioning Hoover, minimalist music is not made in a vacuum. In fact, when it comes to the tweaking of stark tonal palettes and pure silence, context is everything; each time and place has its own ambient default, a given and unconsciously realized backdrop of sonic variables. Figuring out the context that surrounds Michael Andrew Doherty's A_B is the clue to unlocking its gaunt grandeur -- but that's easier said than done. These three compositions, identical in length and nearly interchangeable in structure, fuse clattering and intermittent drones to ghostly, sibilant phases of static. The result is a wash of sounds that sink and surface from consciousness with an organic, almost respiratory cadence. But where fellow minimalist explorers like Steve Reich and Harold Budd learned to relate their work to such external elements as ethnicity and environment, Doherty's self-contained microcosm hints at neither an empirical nor an emotional corollary. And while this insular abstraction makes for a surprisingly compelling listen, it doesn't let quite enough of A_B's own intent or soul shine through.