Has the reign of the soprano diva come to an end? Are we entering an age when the mezzo-soprano rules the operatic roost? The pre-eminence of mezzos such as Cecilia Bartoli, Vesselina Kasarova and Anne Sofie von Otter suggests that these deeper, richer, perhaps more melancholy voices now speak to us more directly than their higher- flying sisters.
Yet these mezzos are not the kind of vocal heavyweights that an earlier generation of mezzos represented. Their singing is fleet and flexible, their range of repertoire immense. Still only 30, the Czech mezzo Magdalena Kozena can surely be added to their number. Since winning the International Mozart Competition in Salzburg in 1995, she has sung at most of the top opera houses in mainland Europe, and earlier this year made her UK stage debut at Glyndebourne, singing the role of Idamante in Mozart's Idomeneo. The conductor was Simon Rattle, the director Peter Sellars: that's the kind of company that Kozena keeps.
Even when she is merely speaking, Kozena has a voice that turns heads: dark, richly resonant and punctuated by an infectious, almost girlish laugh. She is a thoughtful speaker, careful but confident of her ability to communicate, even in English, which must be her third, fourth or even fifth language. "When I was a child," she recalls, "I already had a really low voice, almost a bass. Later, when I started to study, I was considered an alto, and now some people wonder if I'm not really a soprano. But we shouldn't get hung up on these boxes. Today, any mezzo has to have almost the same range as a soprano, so perhaps it isn't a question of the range of the voice so much as the character, the colour and temperament that make up the voice-type.
"Perhaps my voice is richer, more mature than 10 years ago. I'm older, of course, but it's also because the instrument singers have is part of us, and things that you experience go straight into the voice."
She already has a dozen or so recordings to her credit, and several have won prizes, including a 2001 Gramophone award for her recital of songs by Czech composers, including Dvorak, Janacek and Martinu. Kozena is understandably evangelical about her native language: "I love singing in Czech, and yes, I feel a kind of obligation. Most singers don't dare to sing Czech music because they're afraid of the language, and I understand that, it really is difficult. But I enjoy the challenge of presenting this music to people abroad. I'd love to sing all those wonderful Janacek roles, such as Jenufa, but unfortunately I don't have the right voice. Janacek didn't think much in terms of mezzo-sopranos, though I'll be singing Varvara in Katya Kabanova next year, at the Met in New York.
"And maybe," she adds, mischievously, "in 30 years' time, when I no longer care about my voice, I'll sing Kostelnicka in Jenufa..."
That's for the future. For now, Kozena spends a large part of her time singing baroque music. Much of this was written for castrati, who were in plentiful supply in the 17th and 18th centuries, but are rather thin on the ground today. Some deal with the problem by resorting to male counter- tenors, but even such falsettists can't always get as high as the repertoire requires. For many people, mezzo-sopranos are the preferred option, which is why so many of Kozena's roles demand a bit of mannish cross-dressing: Idamante in Sellars' Idomeneo, for example.
"The challenge of playing a boy is a strange feeling for a woman, but you learn the tricks, you learn how to move," she explains. "There is something about playing a man that gives you a certain strength. Men are stronger, more stiff, I would say, so sometimes I put more dramatic emphasis into my voice because I am trying to be stronger, less relaxed than I am normally. It depends on the production. In Idomeneo, for example, gender wasn't so important. What Sellars wanted was real feelings, and they're identical for men and women. At least the basic feelings. Now it doesn't matter whether I'm playing a man or a woman, or whether I'm wearing trousers or a skirt."
Next week, she takes another trouser role for her London operatic debut, albeit in concert performance only, of Gluck's 1770 opera Paride ed Elena (Paris and Helen). She will take the part of Paris, the last role Gluck wrote for a castrato. Kozena has already recorded two of his arias for one of her recital CDs, and has sung the complete opera in the baroque Drottningholm theatre in Sweden. She doesn't think the lack of a staging for the London performance is much of a loss: "It's a rare opera, but perhaps its strength is not in the drama. It's a pity Gluck is so neglected, because I love the music. Its simplicity is disarming, but there is something quite profound there: it releases deep feelings."
Her latest CD finds her tackling quite different repertoire: French music of the 19th century (and, briefly, the 20th century, in the form of an aria from Ravel's L'Heure espagnole). She lives in Paris now, and her French seems good. It was not always thus. The CD is conducted by Marc Minkowski, with whom she has worked many times. She recalls their first encounter with amusement: "I thought Germans were strict about how their language was sung, but the French are even more so. The first time I met Marc, he invited me to take a small role in Gluck's French opera Armide. I studied the two pages I had to sing very hard, and with a language coach, but when I sang for him, he said, 'This girl sings well, but I can't understand a single word'. I was so hurt, but I said to myself, 'You'll see, one day I'll do it'. And I think I'm slowly getting there."
One senses a steely determination that, allied to Kozena's questing musical imagination, will surely carve out a unique career path for her. If this really is the dawning of the age of the mezzo, Kozena looks set to be one of its jewels.
'Paride ed Elena' at the Barbican, London EC2 (0845 120 7550), 21 October. The CD of French arias is on the Deutsche Grammophon labelReuse content