Mariss Jansons leads a lean, taut, non-indulgent performance of Mahler's Sixth (1903-06) — a work colored directly by personal tragedies, in which swaggering marches jolt up against darkly roiling mystery and apocalyptic hammer-blow climaxes; yet it's also the most formally clear-cut and "classical" of all his symphonies. The tightly wound feeling Jansons brings to this work makes it particularly intense and chilling (something he also understands about the music of Shostakovich, which he also conducts brilliantly).