BOSTON SECESSION, a polished, finely blended chamber choir founded in 1996, takes an expansive view of Minimalism here, with some works that are Minimalist only in the sense that their melodies are spare and their rhythms hew close to those of the text, and some that are hardly Minimalist at all. But that’s probably the point: so many footnotes, nuances and reinterpretations have accrued to the definition of Minimalism over the last 40 years that as a stylistic label, it is now as nonspecific as any other ism. Gavin Bryars and Arvo Pärt, composers often associated with the style, are represented by atypical scores. Having used Minimalism’s repetition and vast time scales freely over the decades, Mr. Bryars abandons both in “And So Ended Kant’s Traveling in This World” (1997), a compact, darkly ruminative setting of a passage from Thomas De Quincey’s “Last Days of Immanuel Kant.” Mr. Pärt’s “Beatitudes” (1990), his first English setting, unfolds with chantlike simplicity over an organ pedal tone. The action is in the harmony, which blossoms in each of the 12 verses. William Duckworth’s “Southern Harmony” (1981) draws a line between the repetitive solfège singing of early Philip Glass and the actual source here, William Walker’s “Southern Harmony and Musical Companion” (1835). Mr. Duckworth’s elaborate, often densely beautiful settings touch on other styles too: “Wondrous Love” begins in a melismatic, neo-Renaissance style. In “Transport” (2006) — a fragment from a full-evening work, “Testimony of Witnesses” — Ruth Lomon weaves poetry by Holocaust victims and survivors into a seamless narrative and sets it to music of clarity and pained urgency. Nothing about the score seems Minimalist, but Ms. Lomon’s haunting vision of tightly packed cattle cars bound for concentration camps is the disc’s most striking score, and it receives the most powerful performance.