Substituting for an ailing Jacques Klein, the Brazilian pianist Antonio Barbosa gave what seemed less than his best to a Terrace Theater recital last night. Though his style appears, in any case, to be marked by a certain detachment, Barbosa showed little evidence of an emotional investment in the evening.

There were occasional moments which hinted at reserve resources, most notably in the Prelude and Fugue from Villa-Lobos' 'Bachianas Brasileiras" No. 4. Here Barbosa's susperb control of touch and immaculate clarity of concept imparted a sinewy strength to the sparse lines. His subtle and slightly angular treatment of the repetitious melody in a Chopin Mazurka also pointed to the possibility of some highly individual interpretive capacities.

However, the promise remained for the most part unfulfilled as Barbosa offered agility without conviction. An opening Haydn sonata was skillfully yet superficially executed, and the easy flow in a series of Debussy preludes was marred by a lack of sensuous warmth. This indifference extended into the technical area a few times, most obviously in some sloppy octave passages and less than clear finger work in a few of the Chopin selections. But the suspicion remains that Barbosa is capable of much better performance.