The Masterworks Chorus emphasized theatricality in its concert Saturday night at Bradley Hills Presbyterian Church. Celebrating its 10th-anniversary season, the chorus presented the world premiere of "Requiem for Unbelievers," a work commissioned by the group from its founder and first director, Roger Ames. The performance was a highly charged emotional experience, the sort that often results when sympathetic performers confront for the first time a work with the intensely personal qualities that characterize Ames' composition.

The inspiration for "Requiem" came from the visionary poetry of Anne Sexton, whose frank expressions of a fear of death and uncertainties about God apparently struck a sympathetic chord with the composer. In putting together his text, Ames chose selections in Latin from the Requiem Mass, interspersed with and superimposed upon poetry by Sexton and also by Rene'e Neblett, who participated in Saturday's performance as narrator. The result is rather like a simultaneous translation and commentary, with the daring poetic questions having even greater impact by being expressed alongside the mass text. The mood moves from an opening pessimism to a guarded hopefulness at the end, and Ames has underscored this transition with music displaying admirable craft and imagination.

Using only a 13-piece orchestra in addition to piano, organ, soprano and tenor soloists and chorus, Ames has created an amazing array of both delicate and powerful sonorities. His style is unabashedly tonal and lyrical, and he makes excellent use of the choral sound, which in this performance was a beautifully balanced and blended one. Soloists Anne Johnson and Gordon Hawkins were more than equal to their tasks, and conductor Jeffrey Rink molded the work of all the singers and instrumentalists into as memorable a premiere as any composer could wish for.

The program opened with Stravinsky's "L'Histoire du Soldat" in its original guise as a theater piece. Rink conducted a polished performance in which the instrumentalists seemed to catch fire from the three actors who presented the narration in a most articulate and dramatic fashion.