Musica Humana, a new Baltimore-based chamber ensemble led by Alton Thompson, featured works of Mozart and Vivaldi on the first program of the summer concert series Sunday at the National Presbyterian Church. Considering the group's recent formation and its young personnel, it is understandable that Musica Humana seems to be in the process of getting its footing and establishing a musical style.

Soprano Robyn Woodle, soloist in Vivaldi's "O qui coeli terraeque serenitas" and Mozart's "Exsultate jubilate," aimed for a lyrical approach in both works. She could have stood better control while reaching for leaps in the scale, and her overall tone might have fared better with more even vocal support. Still, she achieved a bright quality in places, particularly in the Mozart closing "Alleluia."

With fewer than a dozen players, the small orchestra was stiff at best in its accompaniment of the vocal selections, and it was at a real disadvantage competing with the concert grand piano in Mozart's Concerto No. 6 in B-flat, K. 238. Pianist Nanette Butler Shannon moved freely over the keyboard, giving thoughtful weight to phrasing in the second movement and offering smooth passage work in the lively finale. The orchestra, however, had intonation problems, especially in the winds, and wasn't able to give enough in the way of balance or ensemble. Surely with time the group can refine its presentation and repertoire.