The Fairfax Symphony Orchestra presented two very different examples of 20th century music Saturday night at the George Mason University Center for the Arts.

Michael Colgrass's 1966 work "As Quiet As . . . " used the entire orchestra as part of a percussion ensemble with traditional instruments played in unusual ways.

As the title suggests, it was percussion to very gentle effect. Composer Colgrass based this 1966 work on fourth-grade students' completions of the phrase "Let's be as quiet as . . . " Colgrass chose seven evocative answers: A Leaf Turning Colors, An Uninhabited Creek, An Ant Walking, Children Sleeping, Time Passing, A Soft Rainfall and The First Star Coming Out.

Colgrass's written purpose -- "to depict the very nature of each metaphor . . . the essence" -- was beautifully accomplished by the music, with little events of sound scattered across the large orchestra like ants on the anthill. Dream sequences used variations on an early Beethoven sonatina and an incredible finale gave the sensation of a whole galaxy of stars breaking forth from the firmament.

It was honest, imaginative and quite wonderful work. The orchestra played with care and close attention to conductor William Hudson to create, at least as could be determined from first hearing, an exemplary performance.

The other recent music came from the incredible output of Kurt Weill, who began as an opera composer in Germany and ended up as an American composer on Broadway.

Baritone Jerome Barry sang six Weill songs that spanned his career. Barry is a fine talent, with excellent diction and delivery and with a beautiful voice that only occasionally seemed to be strained at the top.

The best of the songs was "Moritat von Mackie Messer" (better known as "Mack the Knife"), which was sung in German. Barry told the tale of casual horror with implacable drive: verse after verse continued without break as he described the adventures and attitudes of the omnipresent villain.

Barry handled the more lyrical songs with an easygoing style, although each note tended to swell and diminish individually at the expense of overall line. This "pop" style worked in "My Ship," but was less effective in "Lost in the Stars," which he also took quite fast. It sounded much too glib: the deeper message of humankind's isolation in the universe was missing.

Hudson and the orchestra were superior accompanists, strongly supporting but never overpowering the singer.

The prominent unison melody by three clarinets was a promising opening to Tchaikowsky's Symphony No. 5 in E Minor (Op. 64). Although his tempo was on the slow side, Hudson built a solid first movement with a fine climax. The second movement began beautifully, with a finely controlled horn solo by Karen Sutterer Thornton. But as the work progressed it seemed that all the complexities and inner voices were just happening, without purpose.

Beethoven's overture "The Consecration of the House" (Op. 124), which opened the program, worked well as a short, loud curtain-raiser, and the opening provided a paradigm for some of the problems to come in the Tchaikowsky. The five opening chords created a crisp pulsation that promised much, but a few beats later these same chords became a vapid and inaccurate accompaniment to the now dominant melody.