Vocal recitals are generally presented and received as solo performances, but, under the best of circumstances, they are concerts of ensemble music, the collaboration of a singer and a pianist.

Mezzo soprano Dame Janet Baker and pianist Martin Isepp joined artistic forces for such a performance at the Kennedy Center Concert Hall on Saturday. Each gave significance to the role of the other, and the ensemble had a life and a vitality of its own.

The program was an uncompromising one, heavy on the pain and longing and Gothic romance of Teutonic lieder. But Dame Janet, in luscious voice, resisted any temptation to be cute or less than serious, reserving that for the concluding Gounod set. Instead she explored each text with a marvelous repertoire of subtle sounds and different voices, aided immeasurably by her superb diction.

Her shift from the energy of the hunter to the languor of the sorceress in Schumann's "Waldesgespra ch" was a masterpiece of delicacy, and her stunning pianissimo in "Mondnacht" of the same set somehow filled the hall with sound.

Isepp, for his part, provided her with the sound of a lute in Schubert's "An die Laute," all sorts of nature sounds as needed and whole worlds of light, shadow and scenery.

There were some songs here that did not ring true; the performance of Schubert's "Gretchen am Spinnrade" featured a ripely mature Gretchen instead of the teen-ager of the story (Lotte Lehmann, singing this an octave lower during a master class at the age of 77, managed to create an aura of youth); and Strauss' "Morgen," sung in a carefully controlled pianissimo, never unfurled its splendor. But these were short moments in an otherwise lovely evening of music.