Evelyn Simpson-Curenton's ambitious cantata for chorus, soloists, and instrumental ensemble, The Voices of Freedom, was the best model: The composer added nothing foreign to her source material - including texts by Sojourner Truth and the civil-rights anthem "Ain't Gonna Let Nobody Turn Me Around" - but found unexplored implications that germinated into something larger.
Solo arias, sung mostly by Marietta Simpson in excellent voice, tapped into the rhetorical power of the spiritual. Much of the solo flute parts, played by the composer's daughter Julietta Curenton, was long-breathed melodic lines suggesting Debussy with the blues. Choral forces (Ambassadors Chorale, the Clayton White Singers, and the Lloyd Mallory Singers) were pushed to their limits but rarely lost conviction.
David Sanford's excellent five-movement instrumental piece Grace Canticles incorporated spirituals into a mixed string/winds instrumental quintet with much of the Americana feel of Copland's Appalachian Spring (the theater-orchestra version). Much was hypnotic: One instrument echoed another, with the echo hanging in frozen suspension. The slow movement had dreamy piano writing suggesting Messiaen and a more amorphous spirituality.
The brainiest (and least-appealing) approach came from composer Alvin Singleton, whose Sweet Chariot for a wind-dominated quintet had fragments of "Swing Low, Sweet Chariot" playing hide-and-seek with the piece, testing the toughness of the source material's charm. The spiritual held its own, but to what purpose?
Contact music critic David Patrick Stearns at dstearns@phillynews.com.