Throughout his professional career, bassist Gary Peacock has associated himself with keyboardists who’ve pushed the boundaries of one of the genre’s more common formats: the piano-bass-and-drums trio. Playing with such legends as Bill Evans, Paul Bley, and Keith Jarrett, Peacock brought an open, melodic approach to an instrument traditionally expected to play timekeeper and not much else. These experiences pay off greatly in his current duo with pianist Marc Copland. Stretching the format to its extremes, both musicians find plenty of room to work with (and around) each other, giving their music a free-floating feel. Peacock’s thick tone on the bass takes up much of the space that would normally be occupied by a drummer, but leaves things open enough to give the pair’s ideas room to develop at their own speed. Copland and Peacock play at 7 p.m. at the Corcoran Gallery of Art’s Frances and Armand Hammer Auditorium, 500 17th St. NW. $35. (202) 639-1700. (Jacob Long)