The Corcoran's Great American Songwriters Series concluded yesterday afternoon with a program divided between the music of Cole Porter and Harold Arlen.

The task of preserving the wit and elegance of Porter's lyrics went to Buddy Barnes, who acquitted himself in an engaging if not always successful manner. One must surely acquire a taste for Barnes' singing. Words come out of him sounding as if wrapped in sandpaper and his phrasing occasionally stops just shy of smoker's cough.

As a result, much of what he performs sounds the same, or was distinguished only by his own full, rhapsodic accompaniment on piano. The exceptions were generally songs better suited to his vocal limitations -- the narrative "Miss Otis Regrets," the salon song "Down in the Depths," and a few others.

By comparison, Richard Rodney Bennett slid into his relatively unfamiliar role of cabaret singer with remarkable ease. Each of his piano arrangements reflected his view of Harold Arlen as a jazz composer, first and foremost. Some tunes sparkled with syncopation, others were rooted in the blues, and they were all blessed by a voice pleasant yet effective. Bennett's performance was a fitting end to a series that has brought several fine musicians to town in recent months.