Among the piano, the cello and the flute there are profound and multifaceted differences that could easily amount to incompatibility. Keyboard-driven thunder, silvery chirps and the mellow massage of string on deep-voiced string -- how can such contrasted sounds work together? This question may have been in Ned Rorem's mind in 1960 when he composed the Trio for Flute, Cello and Piano that was performed Saturday night in the Kennedy Center Terrace Theater. At least, the strikingly different personalities of the three instruments emerge as one of the organizing principles of the music and a primary source of its fascination: cello melodies flowing warmly amid shimmering piano chords and flute arpeggios that dart like lightning; a tapestry of constantly shifting and ever-fascinating sound-textures, charged with drama and produced with the greatest imaginable economy of means.

The Rorem Trio was played by the Chamber Artists of Washington, who usually perform at the French Embassy, as part of the Kennedy Center's commendable "Washington, Front and Center!" series, introduced by former artistic director Marta Istomin to serve as a showcase for the best local musicians. Like the music it programs, this six-member group was organized (by pianist Margaret Otwell) on a principle of maximum diversity and contrast. Besides Otwell, it includes soprano Rosa Lamoreaux (who sang four Mozart songs exquisitely), flutist Karen Johnson, violinist George March, violist Michael McLelland and cellist Evelyn Elsing -- some of the city's most accomplished chamber musicians.

The string players opened the program with the old-fashioned but marvelously imaginative Trio of Ernst von Dohnanyi and closed it, with guest pianist Enrique Graf, exploring the power and grace of Brahms's great Piano Quartet in G minor. Balancing familiar and unfamiliar material, the program was performed with technical fluency and expressive depth.