Pendulum Hall in the Museum of American History swung Saturday evening in glorious tribute to composer Thomas A. Dorsey, founding father of gospel song. The free concert and the afternoon's colloquium were part of the Smithsonian's Program in Black American Culture.

Four very different groups illustrated splendidly the potential stylistic variety of the idiom. Solo singer Ronald Lee Huff, accompanied by the piano, blended ecstasy and dramatic urgency with a powerfully delivered "Ship of Zion." The 20-strong Rev. Donald Vails Choir had the "congregation" swaying slowly from side to side, shouting "Amen" and clapping in time to an a cappella "Ain't That Good News" and the call-and-response "preaching" of its dynamic conductor on "How Many Times," which was backed by organ, electric bass and drums. Henry Davis of the Henry Davis Singers played a blues-drenched, striding piano with contemporary touches. The pianist seemed to inspire the group, which included the riveting gospel lift of Rhonda Roundtree. The astonishing unison perfection of the singers was one of the night's highlights.

However, the highlight of the celebration was the opening set by the Harmonizing Four, six men whose molasses-smooth arrangements, pew-rocking beat and fervor of conviction made for a deeply felt experience.