"Maria Callas defined what it meant to be a diva. And Callas remains one of the towering figures of opera. But, exciting as Callas was as a performer, her voice began to decline while she was still relatively young. Experts and fans alike c ontinue to question what exactly happened to a voice that was both exhilarating and controversial.The year was 1952, and Callas was performing what would become one of her legendary roles Bellini's Norma at London's Covent Garden. There were high expectations about Callas' appearance, and opera critic John Ste ane was in the audience. What he remembers vividly was the opera's most challeng ing aria, "Casta Diva," and the feeling that Callas might not hit the highest no tes. "You felt that any miscalculation, just the tiniest degree of miscalculation, an d the thread might break; disaster might come. Now, it didn't happen. But there was a certain tension in the air as to the sheer vocal security." One Singer, Two Voices Just a few years earlier in Venice, Callas had stunned the opera world with the extraordinary range of her voice. She was performing Brunnhilde in Wagner's Die Walkure, a heavy, challenging role that played to her strengths. Then, on very s hort notice, she was asked to step into the part of Elvira in Bellini's I Purita ni. James Jorden, editor of the online opera site Parterre Box, says no one thou ght a dramatic soprano like Callas could sing the role of Elvira. "This was almost the polar opposite [of Wagner]," Jorden says. "It showed off ex tremely high range. It also showed an ability to sing coloratura, which is a fas t, fluid way of singing music that is ordinarily not easy for the more dramatic singers. So people were looking and saying she's the most astonishing singer any one's ever heard of, and yet no one had ever heard of her."

Callas' ability to sing such a wide range of roles was one of the things that le d to her meteoric rise. But critic Conrad Osborne says it also contained the see ds of her vocal decline. Callas' voice was already starting to fail her by the t ime she was in her 40s quite young for an opera singer. A number of factors, inclu ding a rapid loss of weight, may explain why. But Osborne, who also teaches voic e, says Callas lacked the proper technique to sustain her ambitious repertoir Inviting Trouble "It's very unusual to combine those two ways of singing and to extend the range over that wide of a compass," Osborne says. "And if your structural technique I'm talking about the way the voice is balanced and structured so that when you thro w a lot of energy into it, the way an athlete does, the coordinations that respo nd are balanced and efficient isn't true all the way up and down that very wide ra nge, then you're inviting some trouble." But for Callas fans like James Jorden, the diva more than made up for her vocal flaws with her talent for bringing the music to life. Her imperfections set her apart, and her ability to find the emotional meaning in a role was unsurpassed. "One thing about her voice that made it so striking is that it was unlike anyone else's," Jorden says. "Sometimes, it had sort of a hollow sound, sometimes a ve ry dark sound, sometimes a little shrill on top. So it was an extremely distinct ive voice. More important that that, I think, was what she did with the voice; h ow she used the voice as an expressive instrument." University of Southern California professor Tim Page says that Callas brought a

sense of daring back to opera: She challenged her audience and never bored it. "The thing about Callas was there was always a keen dramatic intelligence and a real sense of harrowing intensity to her singing, which I think made her extreme ly special," Page says. "I mean, when you listen to Callas, even after her voice had started to go, it still tends to be an unforgettable musical experience." Page points to Callas' performance in Bizet's Carmen, late in her career, as an example of the kind of dramatic depth she brought to a role. "She really is the raw, untamed gypsy girl," Page says. "There is just a ferocit y and an intensity here, which you're not really used to from a lot of the recor dings of it beforehand, which would concentrate only on nice melodies, prettily sung. Callas' Carmen was not necessarily very pretty, but it was thrilling." A Great Work Of Art What makes Callas' voice and her performances so distinctive, according to Jorde n, is their complexity. Like any great work of art, he says, one wants to keep c oming back to her performances over and over again. "Every time you come back to a great work of art, you see something different, b ecause you are a different person," Jorden says. "With Callas' singing, even hea ring three or four notes strung together, you hear, 'Oh, I didn't hear how she d id that before. That's so beautiful; to take just these few simple notes, and to go from this note to that note in such an elegant and graceful way, shows so mu ch and means so much.' And so, every time you listen, you hear something a littl e different. You hear something a little more sophisticated." When Jorden was a teenager, Callas made her last tour. It was not well-received. But looking back on it now, Jorden says he regrets not having made the effort t o see her. (She died in 1977.) Because, after all, there will never be another M aria Callas."