Lisa Fischer has long been considered a singer’s singer. She won her first Grammy Award in 1992, for her R&B hit “How Can I Ease the Pain,” and in the years since she’s become a first-call backing vocalist, sharing the stage with the Rolling Stones, Tina Turner, Sting and, for more than two decades, the late Luther Vandross, among others. The 2013 Oscar- and Grammy-winning documentary 20 Feet From Stardom reminded audiences of her prodigious vocal skills and helped revitalize her career as a solo artist, and Fischer and her working band, Grand Baton, are now staples of the festival, club and theater circuit. We caught up with Fischer, 58, on the last day of her sold-out weekend at Blues Alley in Washington, D.C. Her perceptive comments were marked by insider’s insight and punctuated by joyous laughter.