There are so many layers to the phenomenon known as the Boys Choir of Harlem that to cover any of its performances adequately probably requires at least three different reviews. The choir made its annual appearance at the Kennedy Center Concert Hall on Sunday, under the auspices of the Washington Performing Arts Society in a production polished and choreographed to perfection.

Musically, this choir has carved out its own niche in the spectrum of boy-choir sound. Light-years away from the transparency of the English tradition or the voluptuousness of the German one, the choir's sound comes out of the singing tradition of gospel music at its most full-throated. It has the ringing sound of trumpets played with focus and control. Under the direction of its founder, J. Walter Turnbull, the choir sings with exemplary diction, a compelling rhythmic integrity and outstanding intonation.

As performers, these singers are winners. They began with nicely and dutifully sung readings of three psalm settings--by Aguiar, Bach and Glick--and then hit their stride in the rest, where they could sing, dance and cavort their way through sets of spirituals, pieces by Gershwin and Ellington, music from Africa and pop America and, finally, a gospel set. "Gumboot Dance," a cross of tap, clogging and Slavic folk dancing choreographed by Tsepo Mokone, brought down the house. The energy that lit everything the boys did was palpable.

The Boys Choir of Harlem is also the clear and present manifestation of a social endeavor that has worked. The group that so thoroughly entertained a full Kennedy Center theater is just a small representation of a 500-student choir school of boys and girls, an institution that for 30 years has proved to its students that hard work is the path to achieving the best that they can do. And this best is quite wonderful.