The Chamber Music Society of Lincoln Center performed a sandwich last night in the Kennedy Center Concert Hall: two pieces for strings surrounded by two pieces for piano duet. The sandwich was always nourishing, sometimes highly spiced, and intricately balanced in its flavors and textures. Like most programs given by that ensemble, it was thoughtfully planned and expertly performed. It might have been marginally better, but it delivered a high level of satisfaction.

The final and climactic piece on the program was Barto'k's Sonata for Two Pianos and Percussion, a solemn, savage, delicate and powerful celebration of the kinds of sounds that can happen when things are banged together: piano hammers on strings; sticks on tympani, bass drum, snare drum, triangle, tam-tam or xylophone. It is not performed nearly as often as its quality deserves, and any performance is a special occasion.

Ideally, the music may have a shade more terror, a shade more radiance than was heard last night, but duo pianists Lee Luvisi and Richard Goode explored its colors, emotions and dynamic rhythms conscientiously and with fine technique. They were ably assisted and sometimes eclipsed by percussionists Richard Fitz and Gordon Gottlieb, who contributed almost as much visually as sonically, moving about the stage behind the pianos to commit acts of aggression on one instrument after another.

Even in the Sonata's moments of silence, the percussionists maintained the music's tension, hovering over their instruments, counting beats as they waited to pounce again. Sonically, they produced a variety of low growls and high tinkles, accents to jolt a melodic line, hints of thunder and earthquake. The dialogue was precisely coordinated among the four players.

The pianists opened the program with Mozart's Sonata for Two Pianos in D, K. 448, a playful, lyrical essay in keyboard dialogue that remotely foreshadows what Barto'k would do more than 150 years later. The two players sometimes sounded like one four-armed pianist.

Between the piano items, the string players explored two extremes of string texture: Brahms' Sextet No. 1 in B-flat, Op. 18 and Ravel's Sonata for Violin and Cello. The Brahms is built as solidly as a pyramid and has only slightly more formal interest. Like a pyramid, it has a low center of gravity, with only two violins to balance the deep utterances of the two violas and two cellos. It might be considered a study in shades of brown. The expert players found some fascinating textures, with particularly impassioned playing by first violinist Ida Kavafian, but the music seemed, as always, a bit longer than necessary.

In contrast, Ravel's sparse, enigmatic and brightly colored Sonata for Violin and Cello derived maximum effect from minimum resources. Kavafian again played beautifully, and so did cellist Fred Sherry.