Three listens to David Hazeltine’s The Classic Trio and the disc still hadn’t made much of an impression. Hazeltine is a fluid pianist (but then he’d have to be to lead a group and record a CD), and the group nicely supports its leader (natch), but there weren’t any distinguishing characteristics. As I tooled around the office, a nice melody would occasionally filter through the commotion, but mostly the music just floated along in the background. But since so many people think of jazz as cocktail music, played for ambience rather than egghead analysis, it’s perfectly reasonable to only half-listen. So when the David Hazeltine Trio plays tonight and tomorrow, gently clink your wine glasses, quietly talk about the day’s events, and once in a while, prick up your ears. At 8:30 & 10:30 p.m. tonight and Saturday at the Willard Hotel’s the Nest, 1401 Pennsylvania Ave. NW. $14. (202) 628-9100. (Christopher Porter)