If every concert this season could give its audience what Donald Collup gave his Phillips Collection listeners yesterday afternoon, this would be a golden year.

Collup was heard at the Phillips last spring as an excellent pianist. Yesterday he opened the 39th season at the Phillips as a light lyric baritone with extraordinary gifts. From his opening "Ombra mai fu" by Handel, to his closing encores -- "Chanson triste" by Duparc, and "Hotel" by Poulenc -- Collup sang with unfailing beauty of sound, in fine Italian, polished French, clear German and sensitive English, and every word he sang was easily understood.

His program, which included Beethoven's "An die ferne Geliebte," Faure's "Poeme d'un jour" and Ravel's "Histoires naturelles," also offered the world premiere of Jean Eichelberger Ivey's setting to Whitman's "Crossing Brooklyn Ferry." In varying moods, this proved a lyrical framework in which the natural rhythms of Whitman's lines led into some touching passages.

In all that he did, Collup found the key to the composers' and poets' inner meanings. At the moment his voice is very light, high in appeal, and handled uith exquisite taste. It needs only a deepening and strengthening of natural resonance, and a still greater projection of every syllable to make Collup one of the world's foremost singers of songs. He was admirably served by pianist Walter Huff.