E-Mail This Article to a Friend Some surprises Boston Lyric Opera’s Cosí, Opera Boston’s Luisa, and Mahler at the Boston Philharmonic and the BSO BY LLOYD SCHWARTZ

Boston Lyric Opera productions have had so many bad ideas, it’s a pleasure to report that the season-ending Cosí fan tutte, Mozart’s sophisticated comedy of infidelity, is actually a very pleasing traditional production — no awful gimmick undermines either the music or the story. It’s not very probing, and it doesn’t fully deal with the musical dimensions that take Cosí beyond comedy. But with the good cast, expert conductor, and smart staging, I came away feeling that I hadn’t been cheated. (Remaining performances are May 9, 11, and 13 at the Shubert.)

A week before the opening, it was announced that conductor Charles Ansbacher, music director of the Boston Landmarks Orchestra, who seems never to have conducted a fully staged opera before, was stepping down "for personal and professional reasons." He was replaced by William Lumpkin, music director of BU’s Opera Institute and associate conductor for half a dozen previous BLO productions. Opening night, Lumpkin led a confident performance, both brisk and expansive — one that never let interest in the music flag. In the well-paced overtures, the orchestra seemed a little unsettled, but the playing acquired polish as the evening continued.

David Kneuss’s staging doesn’t bring much new to Cosí, nothing like the legendary Peter Sellars/Craig Smith production’s reminder that Mozart’s characters aren’t birdbrains but people with pasts who know and suffer more than they let on. But he at least keeps character and situation front and center. When Fiordiligi hears that her lover, Guglielmo, has been drafted, she goes into a stupor that nothing can shake. It gets a laugh. But later, when Don Alfonso puts into action his bet that women can’t remain faithful, our virtuous heroine rebuffs the advances of her phony suitor by insisting, in her aria "Come scoglio," that she is "like a rock." You believe her, because you’ve already seen her stone-faced catatonia. Her maid, Despina, gets a big laugh when she emerges from under a table with her face covered with wedding-cake frosting. But Kneuss sets up that laugh earlier, when Despina can’t stop sipping her mistress’s chocolate. Kneuss knows that laughs are better when they come from character. He even has a sly moment that you’d have to be familiar with the plot to catch: the two sisters start to say goodbye to the wrong lovers — a mistake that plays itself out in the rest of the opera. Mozart and librettist Lorenzo da Ponte never tell us who ends up with whom, and neither does Kneuss.

He hasn’t solved all the problems. The duet in which Guglielmo tries to seduce Dorabella, Fiordiligi’s "easier" sister, has no erotic charge. And when Guglielmo lectures the women in the audience about the deficiencies of their gender, a moment begging for some witty stage business, Kneuss just has baritone Keith Phares stand there and sing. Of the six well-matched and attractive principals, Phares may have the least personal charisma, though he’s very good-looking and has a jewel of a lyric voice. Last season, as Rossini’s Figaro, Seville’s favorite barber, Phares sang well but couldn’t maintain the center of comic attention (no one should have been forced to do the business the stage director saddled him with). Cosí fan tutte is more an ensemble opera that doesn’t depend on any single character.

All six singers have appeared with BLO before, and they worked easily together. Soprano Jennifer Casey Cabot, a lot slimmer as Fiordiligi than she looked in last season’s BLO Die Entführung aus dem Serail (when she was quite pregnant), has vocal elegance, stamina, and a sympathetic presence, though she doesn’t have the dark low notes that Mozart devilishly contrasts with Fiordiligi’s high-powered high notes. Fiordiligi is Mozart’s greatest mock-heroic heroine, but in "Come scoglio," Casey Cabot is more self-satisfied than heroic in her grand refusal to be seduced. Still, how many sopranos can sing both "Come scoglio" and "Per pietà" as well as she does? Dorabella is Jossie Pérez, whom more than a hundred thousand people heard as Carmen in the two free BLO performances of Bizet’s opera on Boston Common. It’s good that she’s singing Mozart, which suits her voice. Her Dorabella, here a blonde, is flirtatious to the point of mugging (she reminds me of Julia Louis Dreyfus in Seinfeld). She occasionally reacts to incidents before they occur. But she’s funny, and sexy, and her voice is blossoming. The things she doesn’t know yet are not hard to learn, though they may get harder to learn the longer she’s encouraged to exaggerate.

Ferrando, the more serious lover, is a much richer part than the one-joke character — Alfredo in Johann Strauss’s Die Fledermaus — who was tenor John Osborn’s last BLO role. He has a big, fervent sound that he can afford to scale back to make a little more elegant. But he does well by "Un’aura amorosa" ("An amorous air"), one of Mozart’s most ravishing tenor arias, and he gets creditably through the impossible "Tradito, schernito," an aria with 13 high B-flats, so difficult it’s usually omitted. He and Casey Cabot are at their best in their second-act duet, in which Ferrando finally wins Fiordiligi over.

James Maddalena, hilarious and touching as Guglielmo in the Sellars/Smith production, is the only singer here to approach a true, and understated, 18th-century style. As the dapper realist (is he really a cynic?) Don Alfonso, he’s in beautiful voice, and he makes the sublime first-act trio and his resigned delivery, near the end, of the line that contains the title of the opera the two most moving moments. Mark McCullough’s lighting — dimming for these magical events — helps too. So does Michael Yeargan’s pastel Bay of Naples backdrop visible behind five working Venetian blinds (it’s distracting, though, to have set changes taking place while people are singing).

The singer who steals the show is Janna Baty as the irrepressible, cake-eating Despina. She has a fuller, richer voice than most Despinas, and the energy level on stage goes up whenever she appears. She also played a servant in her previous BLO appearance, the small role of Berta in last season’s Barbiere di Siviglia. But she’s made Boston history since then as the oversexed duchess in the Boston premiere of Thomas Adès’s Powder Her Face. She isn’t asked to do anything special here, but she makes special everything she does.