VIENNA — In burlesque, in popular prejudice and all too often in the opera house, big-gun German opera comes off as a clash of the titans, with the roles of Brünnhilde, Isolde and Elektra constituting the soprano's triple crown. All three have scenes of great tenderness, but more often than not their defining moments are tempestuous, even savage. For a quarter-century beginning in the 1950s Birgit Nilsson of Sweden hurled their battle cries and curses with the thrust, edge and metal of so many Viking spears. Three decades after her farewell performance even opera lovers determined not to live in the past may still think that no other way will do. But where is another Nilsson?
Her compatriot Katarina Dalayman, who has inherited these great parts, is nothing like her.
"I don't have a steely voice," Ms. Dalayman (pronounced dah-LYE-mahn) remarked backstage at the Vienna State Opera last fall. Days later she would make her house debut, as Brünnhilde in "Ring des Nibelungen," conducted by Christian Thielemann.
"A steely voice is impressive," she continued, "but after 15 minutes you want something more. I think my sound is big and round, with a strong core. Mainly — how should I describe it? — I try to find more colors. It's not something I decided. It's just what I do. I try to find the human being."
Where Nilsson hurled spears, Ms. Dalayman aims javelins: lighter in impact if no less thrilling in their flight. And though the fiercer Nilsson also encompassed the great heroines' more vulnerable aspects, Ms. Dalayman's deeply felt portrayals of Brünnhilde and Isolde at the Metropolitan Opera in the last few seasons render comparison academic. This season Ms. Dalayman returns as Brünnhilde in Robert Lepage's new production of "Götterdämmerung," which opens on Friday, and in the first complete presentations of the Lepage "Ring" cycle this spring, alternating with Deborah Voigt.
Wagner — opera of any kind — is a far cry from the music Ms. Dalayman heard as a girl. A daughter of a Turkish engineer and a Swedish seamstress, she grew up listening to Dean Martin and Dionne Warwick. "We had four or five albums in the house," she said. "That was all."
She sang in the school choir, where her voice never blended in. And she was a class clown. People expected her to wind up in theater. But when she was in her late teens a voice singing an aria on the radio sent her on her way.
"I don't know who the singer was or what she was singing," said Ms. Dalayman, who turns 49 on Wednesday. "But I knew that this was what I had to do. And I knew I could do it."
At the Stockholm Conservatory her teacher started her off with Mozart's Susanna, in "Le Nozze di Figaro." "The voice was built step by step," Ms. Dalayman said. "I realized even then that it would become bigger and more dramatic, but you never know how soon. If you take it easy, you keep your voice. If you want to sing a long time, it's a good choice."
Unlike her classmates she confined her singing to the studio, taking no auditions or outside jobs. So in the school's annual showcase for the graduating class on the stage of the Royal Swedish Opera, with full orchestra, she seemed to emerge full blown from nowhere. Contrary to custom the material chosen demanded big, mature voices and had a cast of only three. It was Act I of "Die Walküre." The experiment seems to have done little for the tenor and bass. But Ms. Dalayman has more than kept the promise of her precocious performance as Sieglinde.
She arrived at the Met in 1999 as Brangäne, the heroine's disobedient confidante, in Wagner's "Tristan und Isolde," returning in subsequent seasons as the Duchess of Parma in Busoni's intractable "Doktor Faust"; Marie in Berg's bleak modernist soldier's tale, "Wozzeck" (televised and available on DVD); and Lisa in Tchaikovsky's "Queen of Spades."
Since then the house has entrusted her with one landmark Wagner character after another. Under Valery Gergiev she sang Sieglinde, one heroine of "Die Walküre," which is the second of the four parts of the "Ring" cycle. Under James Levine she sang the other heroine of that opera, Brünnhilde, whose marathon begins in Act II and carries through to the cycle's apocalyptic finale in "Götterdämmerung."
It was in 2009, during the farewell season of the superannuated Otto Schenk "Ring" production, that Met audiences had their first look at Ms. Dalayman's Brünnhilde in "Die Walküre" and "Götterdämmerung" but not in the intervening "Siegfried." A colleague's last-minute cancellation left the house scrambling for replacements, and Ms. Dalayman was one of the international recruits who came to the rescue. In 2013, as the Met observes the bicentennial of Wagner's birth, she is expected back for more "Ring" cycles and a new "Parsifal," starring as the time-traveling Kundry (part serpent, part Eve) opposite the holy fool of Jonas Kaufmann.
Back home in Sweden, to the degree that such a thing is possible for an opera star in our time, Ms. Dalayman ranks as a national celebrity. Her Brünnhilde, initially outfitted with a top hat, veil and riding crop that call to mind Strindberg's Miss Julie, was seen by prime-time audiences not once but twice in telecasts of "The Ring" from the Royal Swedish Opera in 2008. She has since caused a sensation there in the title role of Strauss's "Elektra," obsessed by her father's murder at the hands of her mother.
"What you hear in 'Elektra' is usually so loud and so horrible," she said. "For heaven's sake. She's in a terrible situation. Bring out the human being."
Staffan Valdemar Holm, who directed both the Wagner and the Strauss, appreciates Ms. Dalayman's gifts as a total performer.
"She's always able to bring something to her roles that is a bit more sensual than most singers are able to do," Mr. Holm said recently from Germany, where he is general manager of the Schauspielhaus in Düsseldorf. "And there's something else. She understands that you sing with your entire body and then of course your soul. That's why she also moves so musically on the stage, unlike singers who try to find the best acoustic spot and then want to stay there, looking at the conductor."
Abroad leading maestros give her comparably glowing reports. Philippe Jordan, music director of the Paris Opera, where she recently sang Brünnhilde in new productions of the "Ring" operas, commented last month on the excitement she creates by touching the climactic note of a big phrase lightly at first, then setting it ablaze with a flash of extra volume. "She has great élan," he said. "She doesn't just give you each note. She gives you the musical gesture."
For Daniel Barenboim, who has made a specialty of Wagner's "Tristan und Isolde" over the last quarter-century, Ms. Dalayman was the heroine of choice first for a new production in Berlin, then for his Met debut.
"She's very distinctive, unusually intelligent," Mr. Barenboim said last month from Milan between performances at the Teatro Alla Scala. "She's one of the few who have big voices and are not the slaves of those voices. She sings with great flexibility, as she would with a much lighter voice. She makes it go wherever she wants. I don't know how to put this, but she also brings out a very personal sense of passion in the music. It's neither the prototypical exaggerated Latin passion nor the prototypical Nordic passion that's rooted in deep depression. There's a mystery there."
Perhaps the heart of the secret lies in her faith in the music. Sieglinde's final moments span both extremes, inviting just the kind of overdrawn delivery Mr. Barenboim spoke of. Instead, Ms. Dalayman has soared from depths of listless despair to supercharged rapture with an eloquence all the greater for a note of noble restraint. Unlike other dramatic sopranos who punctuate their agonies with sobs, screams and maniacal laughter, Ms. Dalayman lets tragedy do its work without overlays of gothic melodrama. In a concert performance of "Parsifal" in Amsterdam she even dispensed with extramusical vocal gestures called for in the score.
Her career-long affinity for Wagner notwithstanding, her passions do not begin and end there. She reported for duty in Vienna fresh from her debut as Bizet's Carmen in Stockholm. "Our production wasn't traditional, with lots of swaying and hands on the hips," she said. "I think of Carmen as a strong person, an honest person. She sees people for what they are and doesn't try to be nice so they'll like her. How boring would that be?"
Would she do it again?
"It was bliss, the most fun I've ever had," Ms. Dalayman said, lighting up. "Singing and acting Carmen gave me such joy, for many different reasons. It's not six hours long. It's not all long lines. I was able to act as a woman, be sexy and angry. You can't say that Brünnhilde is a flirty person. You wouldn't say that her keynote is sex appeal.
"After a while I get fed up with Wagner. But coming back to him after Carmen is wonderful. His work is so deep. It has so many layers. Leaving 'The Ring' and picking it up again, you realize how big it is."