The Choral Arts Society of Washington opened its 20th season Sunday at the Kennedy Center Concert Hall with a stunning program of choral and instrumental music.

The rhythmic propulsion of Leonard Bernstein's "Chichester Psalms" had conductor Norman Scribner virtually jumping on the podium with its raw energy. The solos in the second movement, sung by Washington boy soprano Nicholas Anderson, were breathtakingly pure and beautiful.

For Francis Poulenc's Concerto in G Minor for Organ, Strings and Timpani, Scribner turned the podium over to Theodore Morrison while he went to the organ console as soloist. The concerto, which also featured timpanist Fred Begun, was well played, and the orchestra-organ balance could not have been better. However, the pace seemed a little on the frenzied side, and the work could have benefited from more breathing space.

The work the SRO crowd came primarily to hear was Mozart's last masterpiece, the Requiem. The Choral Arts Society gave a solid, thoughtful performance that approached the level of truly inspiring on many occasions. In the Lacrimosa and the Agnus Dei movements the chorus seemed especially involved and consequently sang most beautifully. Mozart's naturally beautiful, soaring lines were well served throughout by this excellently trained chorus.

The quartet of soloists was uneven and sounded better when singing in ensemble than did some of the individual voices. The most sensitive ensemble singing took place in the Benedictus, while other quartet sections were plagued with unsteady tempos. A similar disagreement on tempo took the edge off the potentially thrilling Tuba Mirum section, but bass Stephen Saxon consistently proved to be most impressive.