This Lyric Opera revival of its imaginative though shopworn Jean-Pierre Ponnelle production of Don Giovanni boasts two strong new voices. Bryn Terfel, who sings Leporello, is a burly young baritone from Wales who was raised on a sheep farm and exudes natural authority onstage. He rose through the operatic ranks quickly, with his clear diction and exceptionally versatile vocal range, totally unspoiled by the prettified Oxford choral tradition. Luba Orgonasova, making her Lyric debut as Donna Anna, is likely to put an unconventional spin on the role of a woman spurned. A Slovak native, this lyric coloratura was discovered by Herbert von Karajan, who invited her to the Salzburg festival in 1990. Her voice is supple and radiant, with plenty of nuance and power. James Morris will sing Don Giovanni, the playboy who throws fabulous parties and is in dire need of Freudian psychoanalysis. The top-notch cast also includes Carol Vaness as Donna Elvira, Susanne Mentzer as Zerlina, and Frank Lopardo as Don Ottavio. The new stage direction is by Matthew Lata; Yakov Kreizberg conducts. Friday, Wednesday, and next Saturday, December 2, 7:30 PM, Civic Opera House, 20 N. Wacker; 332-2244.