David Bowie fans have come to expect the unexpected. Still, I doubt that many could have adequately prepared themselves for Low, his latest disc, which features collaborations with synthesizer wizard Eno and only a modicum of vocal work. Though side one delivers more thickly textured music than Bowie has previously offered, the real shockers appear on the flip, where he moves heavily into electronics for a quartet of eerie space-rock extravaganzas. As artistically successful as it is adventurous, the set merits attention from any Bowie aficionado who feels ready for “ch-ch-changes.”