Commissioned by the Handelsbeurs Concert Hall in Belgium, this set is trumpeter Dave Douglas’ musical response to The Adoration of the Mystic Lamb, an epic 15th-century polyptych otherwise known as the Ghent Altarpiece, painted by Hubert and Jan van Eyck. It features one of Douglas’ most unusual ensembles to date, with tuba, pump organ, lute, serpent (an early low-brass instrument), and electronics merging with trumpet, cello, piano, fuzz-tone guitar, and other more familiar sounds. Berlinde Deman, the tubist, sings as well, sometimes joined by Douglas an octave lower (in what might be his first vocal performances on record). The material is complex, with involved orchestrations and strange polytonal harmonies framing sung passages drawn from sources as varied as the Latin Mass and Marvin Gaye. “Instrumental Angels,” where muted trumpet and lute double a melody while cello and tuba double a bassline in counterpoint with a subtly dancing groove, shows the possibilities that arise for unconventional interplay. In his notes, Douglas explains how the music progresses from the Altarpiece’s outer panels, with “muted colors and dank interiors,” to the inner panels, “full of light, showing people from all walks of life.”