I often hear two protestations regarding these options: 1) As voices mature and put on miles, they gain weight and darken in color; progressively heavier repertory is a normal response. 2) These darker qualities are just part of the native Russian linguistic set; nothing to be done about that. Answers:

1) Yes, there’s a tendency toward that. Voices do toughen with age and use. But in voices of superior structural balancing and conditioning, the effect is truly minimal. Barring some accident or misfortune of health, they don’t change much, and neither does their comfort zone of repertoire. Besides, Netrebko’s voice hasn’t taken on weight or grown in size, and instead of solidifying it’s fragmenting.  If she’d been meant to sing spinto or dramatic soprano roles, she could have sung them from an early point—that would have been her “original” voice.

2) Well, that’s not true. Re-listening to the Netrebko Lyudmilla, a couple of other high sopranos came to mind. The first was the Austrian Hilde Gueden, the best Sophie, Zdenka, and Rosalinde of my recollection, but also much valued (by me) as Gilda, Norina, and Euridice. She shared with Netrebko the attributes of physical beauty, sexuality, and theatrical relish, and a high soprano voice of above-average strength. But her technique was markedly different, based on a bright, centered, taut engagement (never the “relaxed” feel of much of Netrebko’s singing) that gave her tone bite throughout the compass, with an unusually open, projective vowel formation in the lower range. (She studied with Otto Iro, an important pedagogue of the interwar years.) As her career went on, she made some moves—to Elvira (not Anna) instead of Zerlina, the Countess instead of Susanna, no more Zerbinettas but Aminta and Daphne, and at length Violetta. And that’s as far from “original” as she went. She could have sung a wonderful Lyudmilla, had that been her cultural milieu. But of course it wasn’t, and since I was speaking of the Russian linguistic set, we need a Russian exemplar.

As it happens, that’s easy. After re-hearing Netrebko’s Lyudmilla Cavatina, I turned immediately to that of Vera Firsova,  who recorded the role with the Bolshoi in 1955. Using Netrebko’s “Russian Album” (2005/06) and the old Bolshoi sets, I also A-B’d Netrebko and Firsova in key parts of two other roles, Antonida in Glinka’s A Life for the Tsar (Antonida’s Cavatina and Rondo) and the title role of Rimsky-Korsakov’s The Snow Maiden (the Maiden’s beautiful farewell from the Act 4 finale). In all these, Netrebko is in good voice and has touching moments. But Firsova is better, and the difference is instantly apparent: her voice is quicker, springier, more spontaneous and released in velocity, more eager to embellish, more consistently tensile and elastic in cantilena. The most easily heard difference in quality is that Firsova’s timbre, though full-bodied and incorporating undistorted dark vowels, is generally brighter; it sounds a mini-category higher than Netrebko’s at identical pitches. On the few passing occasions when chest would be called for, it enters with perfect naturalness. If we listen analytically, we realize that the brightness is a matter of clear, open vowels, especially in the lower-middle range. Even at soft dynamics, the voice retains its tensility, rather than easing off into a relatively slack, shaded quality. And while, yes, she’s Russian, so Russian inflections—as with the back-of-tongue “l(y)” or “l(y)u”—occur, they do not lead to a hooded overlay. This last is not a “Russian” characteristic. It’s a way of handling vocal distributions. ^(I)