In the spirit of its collaborations with jazz artists including Wayne Shorter, Branford Marsalis, and Gregg August, the Orpheus Chamber Orchestra commissioned pianist Brad Mehldau to revisit his Variations on a Melancholy Theme (originally composed for pianist Kirill Gerstein) using the orchestra’s full color palette. The theme itself is bluesy, in a slow-loping waltz feel, started on piano but quickly picked up by clarinets and other winds. Low strings, orchestra bells, and thicker textures soon follow. With woodblocks and snare drum, “Variation 3” picks up the pace as the orchestra more fully reveals itself. Still, Mehldau shines as a soloist: “Variation 6” and “Cadenza” are solo piano, “Variation 9” finds him in playful dialogue with the woodwinds, “Variation 11” has some bracing improvised licks, and the “Encore” variations are a maelstrom of unaccompanied keyboard wizardry, followed by applause (the live recording was made in 2013 and released years later).