Nighttown features pianist Helen Sung twice this week: Tuesday with her quartet and Wednesday backing singer (and Cleveland native) Vanessa Rubin. Sung’s quartet, playing in support of her latest release, Anthem for A New Day, features John Ellis on sax, Hamilton Price on bass and Jamire Williams on drums. The interplay between the classically trained yet exuberant Sung and the groovy, funky Ellis should be particularly fun, and that prospect alone is enough to recommend this show. Rubin, with her recent (at least part-time) relocation to Cleveland, has been performing fairly frequently in town of late (something all jazz fans here should be happy about). If you haven’t had a chance to check her out, this set Wednesday, with the world-class, expressive backing of Sung and local bassist Peter Dominguez (plus a drummer TBA) may be your best opportunity yet.