Ms. Holt, a onetime waitress at the Metropolitan Room, is a subtle, confident singer whose smoky, medium-light voice has a playful kittenish edge. Mr. Simeone, who shares enough similar vocal traits for them to blend, is less inhibited. His voice at its high end suggests a more thickly textured echo of Michael Jackson’s. His version of the ominous Billie Holiday signature song, “Strange Fruit,” about a lynching, conjured starkly horrifying images (which are also vividly evoked in the new film “12 Years a Slave”).As they sang, accompanied by a trio led by the pianist Tracy Stark, their vocal give and take conveyed the comfort of long-term dancing partners familiar with each other’s moves and senses of humor. “Strange Fruit” led off a three-song suite that included “Black Butterfly” (sung by Ms. Holt) and Sam Cooke’s “A Change Is Gonna Come” (sung by Mr. Simeone), which addresses the civil rights movement. If Mr. Simeone lacked the vocal heft to transform Cooke’s classic into a transfixing anthem, the song was infused with enough conviction to justify its inclusion.