Kerry Krebill and Musikanten, her chamber chorus, put together an elegant program of music for their concert at the Kennedy Center's Terrace Theater yesterday, with works by Monteverdi, Bach, Brahms, Ravel and Copland. To do all these composers justice, however, is to meet one of a concert performer's greatest challenges: to find for each piece an idiomatic sound and style, and then projecting each convincingly. Musikanten was not entirely successful in this quest.

The performances of the first and third of the Ravel "Trois Chansons" were splendidly idiomatic. The group has just the breathy sort of tone that the French language and sound require, and its diction and sense of dramatic humor brought the whole audience along.

Copland's "In the Beginning," with the chorus backing up fine solo work by mezzo-soprano Susan Fleming, was also admirable, as the ensemble's well-drilled pianissimos and rhythmic clarity fitted the composer's purposes.

But the same thin sound and narrow dynamic range were not at all what were needed for the rest. Monteverdi's "Lagrime d'amante al sepolcro dell'amata," six songs of anguish, sounded merely sad and slow and lacked the deep sonorities that its original low key was selected for. The Bach Motet No. 2, sung with unusual clarity, nevertheless sounded strained on top and puny throughout, and the Brahms Five Songs, Op. 104, which had fine moments, particularly in No. 4, could have used a couple of additional full-throated singers on every part.