Ms. Nickki, you already know her a little, even without having heard her. She, her sister, her grandmother, had been shaking the stage of black vaudeville theaters for decades when they cut the first blues in the 1920s. their voices of bronze the great orchestras of Kansas City and the pianos of the slaps of New Orleans. Rhythm’n’blues, with Big Mama, the Chicago Blues, with Koko, soul above all have consecrated them. At the end of the 1980s, their little cousin from the Bronx imposed the same freedom, the same sincerity, in macho and flashy hip-hop.