Mocking old folks and the music they love is a regrettable tradition. Yet the joke was on latecomers at The Market at Meadowbrook on Saturday, January 14. Each of the approximately four dozen chairs in the cafe were occupied by geriatric fans of dixieland jazz for the entirety of a two-hour performance by a sprightly trio led by Lynn Zimmer. Old-timers braved sub-zero temperatures to warm their souls to satiny renditions of tunes like “Wolverine Blues,” “Amazing Grace” and “Stardust.” The clarinetist and his colleagues worked the room like vote-hungry politicians at the break. Zimmer has earned what many of the more artistically stylish Kansas City based jazz musicians lack- a large and enthusiastic fan base eager to show up for every performance. There’s nothing old-fashioned about that.