Not many concerts open with a 50-minute lecture. And few lecturers are as animated and boisterous as Rob Kapilow was on Sunday at the Kennedy Center Concert Hall, where the Choral Arts Society performed Mozart’s Requiem, K. 626. And one wonders why so familiar and beloved a work as this even needs an introduction, especially one that occupied the program’s entire first half. The chorus and orchestra performed excerpts from the piece (while Kapilow conducted) to accompany his remarks. But the audience also had to wait through an intermission before hearing a full performance led by Choral Arts Society conductor Norman Scribner.

Although conveying misinformation at times, Kapilow did nail down some interesting points in order to support his theme: “What Makes It [the Requiem] Great?” But, from his first leap onto the stage, his exaggerated antics proved distracting. And while the chorus and orchestra were demonstrating his ideas, he bellowed out repetitious details, overpowering the music.

It was left to the performers to substantiate the most recent views, that far from being depressed, impoverished and obsessed with death while gestating the Requiem, Mozart was enjoying a recent imperial music appointment and churning out some of his greatest symphonies and operas in new ways. In Scribner’s hands, the Requiem was passionate, focused and confident, with immaculate diction and clearly defined phrases reinforcing the meaning of the words. Some minor flaws were the tendency to go under pitch in soft passages and the inclination to overdo some fortes.

The vocal soloists were fine individually — mezzo Laura Zuiderveen and bass Kevin Deas most of all — though often unevenly matched in ensembles. The concert was co-sponsored by the Washington Performing Arts Society.

Porter is a freelance writer.