The best part of the joint concert presented by violinist Chee-Yun and pianist Barry Douglas on Tuesday night at the Kennedy Center Terrace Theater was a fierce, soulful rendition of the Sonata No. 3 in D Minor, Op. 108, by Johannes Brahms.

Chee-Yun treated the work as four impassioned songs, each with its own distinct character yet somehow all of a piece, while Douglas provided firm, unusually formal yet unfailingly eloquent support (indeed, his playing of the Adagio reminded me of the sort of baroque continuo that would propel a sonata by Corelli). The sonata is gorgeous music, to begin with -- urgent and reflective, brilliant and introspective -- and it proved a perfect cap to a warm, brilliant autumn day.

With the exception of an exciting rendition of an early Brahms Scherzo for violin and piano, the rest of the program was less satisfying, mainly because a sonata by Krzysztof Penderecki proved so dreary. What has happened to Penderecki, anyway? He was once considered the most interesting (the best known, anyway) of the Eastern European modernists, and his "St. Luke Passion," with its mixture of tone clusters, anguished chanting and screeching, scraping avant-garde sonorities, is still ranked as one of the most important and influential devotional works written after World War II.

But Penderecki converted to a tame, mostly consonant neo-romanticism a quarter-century ago. Some of his early works in this genre were arresting -- as shocking in their way, coming from him, as some of his self-defining experimental works had been. Still, by the time he completed his Sonata for Violin and Piano No. 2 in 2000, he seems to have been reduced to the stature of a failed clone of Dmitri Shostakovich, employing the same crabbed Gypsy melodies, haunted swoons and angry plucking as his master, but in a different century, with its own, very different imperatives. As a result, I found the sonata surpassingly long and dull; even a taut, committed performance by Chee-Yun and Douglas couldn't save it.

The program began with a curiously wan performance of Mozart's Sonata in B-flat, K. 378. In the first two movements, Chee-Yun's playing lacked both color and charm; it seemed strangely faded, as if she had decided to withhold full physical engagement for some mysterious ideal of stylistic decorum. Only in the finale did she let herself go, and then the results were predictably delightful, as her dark, agile tone melded with the brightly burbling sound produced by Douglas.

One extra-musical carp: a small but determined portion of the audience insisted upon applauding mirthlessly after each and every movement, as if in fulfillment of a grim pact. Concert Etiquette 101, folks: Thou shalt not applaud between movements. The breaks between the different sections of an integrated piece should be sacrosanct, no more to be interrupted than a momentary rest in the middle of a phrase. Chee-Yun and Douglas were rather too polite about this distraction, but the chorus of shushers from the audience grew louder and louder as the evening progressed.

Violinist Chee-Yun performed with pianist Barry Douglas at the Kennedy Center's Terrace Theater.