BERLIN.- Klaus Florian Vogt’s voice is a phenomenon that even he has had trouble grasping. In the early days of his career, he would hear recordings of himself singing and be surprised by the timbre. He knew his tenor was bright, but outside his head it sounded even brighter.

He wasn’t the only one unsure of what to make of his voice. Lithe, polished and powerful, it continues to divide listeners. Some critics find it youthful; others, immature. At 54, Vogt is one of the most essential performers in opera. But “there is no voice that divides fans so much,” music critic Markus Thiel wrote in a review. “‘Ethereal,’ ‘otherworldly,’ some cheer. ‘Boyish,’ ‘Wagner wish-wash,’ others complain.”

These days, Vogt isn’t so surprised by his sound. “It’s continually grown closer, what my imagination is of how I want to sing and what the actual result is,” he said in an interview.

He has also accepted that his voice is not for everybody. “What I never wanted,” he said, “was to pretend to be something I’m not. That’s what’s dangerous for vocal technique and for a voice in general — when you don’t sing with your own voice.”

Vogt is a Richard Wagner specialist, with all of the composer’s major tenor roles in his repertoire as of last year, when he performed as Siegfried in the final two operas of the “Ring” cycle at the Zurich Opera House. On Wednesday, he will sing the role for the first time at the Bayreuth Festival in Germany.

His artistry unites apparent contradictions: His voice is crystalline but easily fills the remotest nooks of the opera house. A widely admired Wagner interpreter, he sidesteps stereotypes of Wagnerian singing. And although he almost never resorts to the speech-song blend other opera singers use for moments of intense emotion, he is one of the easiest singers to understand.

“It’s a little confusing at first,” Andreas Homoki, who staged the Zurich “Ring,” said in a phone interview. “He sings a little boyish, like in a boys choir. But then you notice that he adds that additional breast voice, and his voice retains its lightness in the high register.”

“Especially with Siegfried,” Homoki added, “if it’s always done with this heroic, heavy, full voice, you feel like people get out of breath or that it’s really tiring in the high range. But that’s never the case with him.”

Vogt said that his uncommon voice “has advantages and disadvantages.” But he doesn’t really think about it. “After all, I can’t change it. It’s my voice, and I sing the way I think is right.”

VOGT GREW UP in Heide, a small town in Germany close to the North Sea. His father had once been a music student but left the field for medicine. Still, the art form remained important in the family. As a child, Vogt sometimes fell asleep to chamber music. At 9, he began to play the French horn.

In 1988, Vogt took a position as a section player in the Hamburg Philharmonic State Orchestra. But he grew dissatisfied with the bureaucratic aspects of orchestra life, in which players are made to fulfill a conductor’s musical vision.

“I like to be one of the main people onstage,” Vogt said. “That’s what challenges me and what’s fun for me.”

At a birthday party in 1990, Vogt and his girlfriend, Silvia Krüger, who had studied singing, performed Gioachino Rossini’s “Cat Duet.” (They are now married.) She recorded their rendition of the piece and sent it to her mother, who had been a professional choir singer. Vogt’s future mother-in-law was full of praise — for his voice.

He started to study singing at the Lübeck Academy of Music alongside his orchestra job. In 1997, he was hired by the Flensburg City Theater, and joined the ensemble at the renowned Semperoper in Dresden the next year. In 2003, Vogt became a freelancer, and his career took off. He went on to make his debuts at the Metropolitan Opera in New York and La Scala in Milan.

The only time Vogt imagined returning to the horn was during the pandemic. But his background as an instrumentalist serves him well. Simone Young, who is conducting the “Ring” at Bayreuth, said of Vogt in a phone interview, “When he’s on the stage, it’s rather more like having an orchestral soloist than a singer, in terms of the way he follows, phrases and anticipates.”

Among Vogt’s Wagner roles, his interpretation of Lohengrin captures the part’s enigmatic beauty; his Parsifal makes plausible the protagonist’s development from carelessness to empathetic wisdom. His Walther, in “Die Meistersinger von Nürnberg,” has a lightness that emphasizes the character’s distinct, intuitive musical ability.

As written, Siegfried alternates between childlike innocence and jock menace, though the buff-voiced tenors who sing the part often neglect its softer side. In Vogt’s interpretation of the role for the Zurich Opera House, he allowed the character’s bumbling to show through, leading to moments of gentle, moving comedy.

When Siegfried first discovers the sleeping Brünnhilde, he famously sings, “This is no man” — a silly line when belted. But Vogt made it timid, showing an adolescent overwhelmed as he realizes for the first time how beautiful other people can be.

Vogt’s flexibility as an actor derives from his mastery of the score.

“He doesn’t come from acting, and you can tell,” Homoki said. “He’s a musician, and the first thing he does is make music. He knows exactly what he’s singing, but at first he’s like a blank sheet of paper.”

As a result, Vogt is unusually attuned to Wagner’s quieter moments. Even in the composer’s most heroic roles, “there is very, very much piano to sing everywhere,” he said. “It just isn’t done.” He also carefully balances the volume of the highest and lowest notes of his phrases. Because of that balance, his phrases occasionally lack contour, but his words are easy to understand. Vogt communicates even Wagner’s contorted sentences with rare immediacy.

Now that Vogt has sung every major Wagner role for tenor, he hopes to maintain them. “I love Wagner,” he said, “and if it was up to me, I could sing Wagner every day.”

What makes him an exceptional Wagner interpreter, though, sometimes hinders his performances in other repertoire. His clarity can sound one-dimensional in Franz Schubert, as on a 2023 recording of “Die Schöne Müllerin.”

And because Vogt is always conscientiously singing — he almost never shouts or spits out a word — it’s hard for him to display anger, disgust or irony. His voice is also an awkward fit for lighter fare like operettas and musicals, which he has occasionally performed and recorded.

At a June performance of Erich Wolfgang Korngold’s “Die Tote Stadt” at the Hamburg State Opera, Vogt’s voice lacked the weathered quality necessary for Paul, a character who lives immersed in past grief. His boyish sound felt implausibly unencumbered for an emotionally shriveled character shackled to the past. Still, Vogt sang the part with excellent diction, volume and intonation, and in individual moments made his voice sound strikingly hollow and alkaline.

Vogt, who aims to record Schubert’s song cycle “Winterreise” someday — he has performed an orchestral arrangement of the piece — may never be the best singer to embody world-weariness. That is partly the nature of his voice but also the result of the care with which he treats it. He has been careful not to wear down his instrument. (He was offered the role of Siegfried over 10 years ago but waited to make sure he felt ready.) Though its timbre has changed slightly in recent years, his sound retains a youthful buoyancy and effortlessness.

“I do think that the voice still sounds young and really fresh,” he said. “And of course I want to retain that as long as possible.”

This article originally appeared in The New York Times.