The Theater Chamber Players of the Kennedy Center opened their season Saturday at the Terrace Theater with two modern works followed by two more traditional works. "Imaginary Landscape," by Enrique Raxach, featured William Montgomery on flute and Albert Merz on percussion. Having no specified movements, "Landscape" has a restrained improvisational quality, with an interesting interspersion of the darker-toned alto flute with the brighter "regular" flute. Merz did a particularly fine job managing a host of percussion instruments without overwhelming the flute. "Symbols," by Zsolt Durko with William Purvis, horn, and Dina Kostin, piano, was well played but lacking in thematic interest.

By contrast, Bela Bartok's Sixth String Quartet seemed almost over-structured, each movement having a slow opening "mesto" section -- a sad, mournful quality -- followed by a change in style and tempo. The mesto sections featured fine solo playing by violist Robert Dan in the first movement and cellist Evelyn Elsing in the second. This was especially enjoyable, since the viola and cello are usually used to support, not star in, a quartet. Ellen Payne and Hamao Fujiwara, able violinists, completed the ensemble.

The last part of the program was devoted to Brahms's splendid Trio for Violin, Horn and Piano in E-flat. Kostin, Purvis and Fujiwara were in top form, achieving the bold, classical effect of the first movement and the deep melancholy of the Adagio movement. Purvis gave a notable performance here, playing the challenging horn part with a rich, dark tone and remarkable clarity.