Laurel Masse helped found the Manhattan Transfer, and during the decade or so she lived in Chicago she was a popular chanteuse and bandleader–but for the past six years she’s concentrated on singing without accompaniment. Ensconced in the mountains of upstate New York, a couple hundred miles from the city, she’s been exploring music far afield from vocal jazz, from transcriptions of Bach to Quaker hymns to Negro spirituals and Scottish ballads; she’s also been delving beneath the gorgeous, polished surface of her singing, which never cracked during her Chicago days. Masse has always had superb diction, pitch, and breath control, as well as a five-octave range that verges on freakish; these tools served her well in jazz, where the voice often functions like any other solo instrument. But during her wilderness sojourn Masse has focused on emotional rather than technical virtuosity–and it pays off in every moment of her self-produced, limited-edition Feather & Bone, which contains some of the most remarkable and affecting vocal music I’ve ever heard in any genre. It’s not just that she’s found a way to express her emotional core; it’s that she’s found so many ways, shifting her timbre, her phrasing, and even her approach to the beat to create several subtly different personas. On “Lone Wild Bird” she first imitates a bagpipe’s drone, then softens her voice into a pure, earthy Highland lilt; on “Mother, It Is Night” she darkens her tone, pushing the sound deeper into her throat and finding a breathtaking soulfulness I didn’t know she had in her. The Bach pieces display her unerring pitch and cerebral interpretations–and like all the music on the disc, they practically take flight. Feather & Bone seems destined to become a cult hit once a label snaps it up; until then, you can only buy it at Massé’s performances. Saturday, 6 PM, Congregation Sol-El, 1301 Clavey Rd., Highland Park; 847-433-3555. Tuesday, 7 PM, St. Teresa of Avila Catholic Church, 1037 W. Armitage; 773-975-6330. Also Friday, May 19, 7:30 PM, Pope John XXIII School, 1120 W. Washington, Evanston; 773-784-2002. Massé will perform solo only on Tuesday; on Saturday and on Friday, May 19, she’ll be accompanied by Rich Daniels & the City Lights Orchestra. NEIL TESSER