New York's Orpheus Chamber Ensemble, said to be the largest American chamber orchestra that plays without a conductor, made its Washington debut last night at the Kennedy Center's Terrace Theater. The four works on the ensemble's program normally have conductors. Last night's results were mixed, but it is doubtful that the Orpheus players would have played the Barto'k that ended the program any more beautifully under the direction of a baton.

The Orpheus ranged in size from 12 players in Richard Strauss' Serenade for Thirteen Winds to 23 for Mozart's Piano Concerto No. 17, with soloist Richard Goode.

One really heard no need for a conductor in the Strauss, but in the Mozart, more of the work's deftness and wit might have been possible if there had been a conductor to impose a more specific interpretive mold on the work, especially as to timbres and dynamics.

Still the Orpheus' Mozart was splendid, so far as it went. The one thing that the players do splendidly without direction is play together, a lesson some of our fancier orchestras might heed. But a cohesive overview of the work being unveiled was not always clear. Goode played with crisp, even phrasing, and his exchanges with the winds in the finale were delicious. One thing was clear, though--the Mozart concerto needs a larger ensemble.

A performance of the Haydn Symphony No. 6 in D Major ("Le Matin") had most of the same qualities.

One was surprised at the group's success with Barto'k's haunting, ironic and difficult Divertimento for Strings. Here the interpretation, with 16 players, had a sharp point of view. Timbres were more specific, and those wonderful trills near the end of the slow movement were superbly articulated. Whatever it was about the Orpheus ensemble's working methods that went right in the Barto'k went less well in the Mozart. But the success in the Barto'k speaks well for the merits of the conductorless chamber orchestra.