Phyllis Bryn-Julson was suffering from a virus last week, and her voice was slightly below its usual standard when she sang the world premiere of the Lawrence Moss song cycle, "Somewhere Inside Me," Saturday night with the Theater Chamber Players. But Bryn-Julson slightly below her peak is still one of the musical marvels of our time. It is hard to imagine anyone giving a more impressive performance of this work than the soprano for whom it was composed.

"Somewhere Inside Me," for soprano, flute and guitar, is a cycle of 10 epigrammatic little songs and an instrumental interlude, set to haiku texts by poet Lew Gronich. Although the music is as succinct as the miniature Japanese verse form, it seems lighter, less intensely knotted than the chamber works Moss was composing a few years ago. There is a fine lyricism in the vocal lines, which effectively exploit Bryn-Julson's remarkable range and technical finesse, and the writing for flute and guitar contains some clever descriptive touches as well as mood-setting and a sort of running commentary on the words. In this music, as in Thea Musgrave's "Primavera" for flute and soprano, which opened the program, there were some exquisite moments when the soprano's voice matched the tone of the flute on a sustained note so perfectly that it might have been a flute duet. Flutist William Montgomery and guitarist David Starobin provided admirable partnership for Bryn-Julson.

Hindemith's neatly wrought and adventurous Third String Quartet, which was the centerpiece of the program, sometimes sounds like an alliance of viola and cello against the violins, possibly because Hindemith played the viola and his brother played the cello in its first performance. This weekend, it was superbly performed by violinists Hyo Kang and Naoko Tanaka, violist Masao Kawasaki and cellist Hakuro Mori, who also gave a warm-toned, technically expert reading of Bach's Second Suite for unaccompanied cello.

The second of two works marking Bach's birthday was his Cantata 51, "Jauchzet Gott," which drew some brilliant coloratura singing from Bryn-Julson, though not with quite the effortlessness she shows when not plagued by a virus. A few lapses of ensemble in this work on Saturday night were the major musical flaws in a splendid and well-varied program.