But Utah Opera's "La Traviata" is an example of how that stereotype has largely gone the way of the Viking helmet. Soprano Maria Kanyova, who plays tragic heroine Violetta, is tiny - which doesn't stop her from playing big roles.

Years ago, when the St. Louis native was training to be a singer, "I had a teacher who desperately wanted me to put the poundage on," Kanyova says now, laughing.

She's a good fit - so to speak - for a classic Verdi opera that has strong-willed courtesan Violetta wooed by the dashing young Alfredo - until her dark past gets in their way.

More and more, opera is following theater: Performers are chosen based on their acting abilities and physical fit for a role, not just their stature as singers.

One of the most notable - and humiliating - instances came in 2004, when England's Royal Opera House fired acclaimed American soprano Deborah Voigt for being too fat to sing in its production of "Ariadne auf Naxos." Soon after that, the singer had gastric bypass surgery and lost 150 pounds; she'll be appearing in the Royal Opera's "Ariadne" next season.

Despite the "big body, big voice" idea that persisted for decades, there's no physiological reason a small person can't produce as big a sound as a large one. But for a long time, big stars with big voices got away with unhealthy lifestyles because they could.

For singers now, versatility, not predictability, is key - which means the death of the traditional diva role is largely a good thing.

"I really feel that operatic standards have gotten so much better over the last 50 years," said William Lacey, who will conduct the Utah Symphony in "La Traviata." "Singers now, they're more professional, they're more aware."

Pamela Berlin, who directed Utah Opera's "Of Mice and Men" and "A Midsummer Night's Dream," agrees. "They understand that if they've done the production six or seven times, they may have to be open to new directions."

That means regional companies such as Utah Opera, which don't get the giant international stars, often have better performances. "Big stars, they've done the role 40 times, and 'This is the way I do it,' " said Chad Shelton, the youthful tenor who plays love interest Alfredo. "It's always a better experience for me when I come to a good regional opera company."

Among the regional companies, Utah Opera consistently brings in some of the country's best talent; Berlin and Lacey say the entire cast for this production is top-notch. "This is a kind of New York City Opera kind of casting. . . . It's a posh level," Lacey said.

He says Kanyova, who has sung at the New York City and Boston Lyric operas and is headed after this to the Los Angeles Opera, also has the acting chops to make what could be a walking cliché into a believable, appealing character.

When the opera opens, Violetta is a hard-shelled courtesan who refuses to fall in love. But Alfredo's affections win her over, despite the fact that her social status will ultimately thwart their relationship.

"We think of an operatic soprano, we think of Violetta. But the piece is so much more complex. The music Violetta gets is so complex, and the extent of characterization that Verdi makes through the music is truly phenomenal," he said. "You need a performer who is responsive to that material."

Kanyova calls Violetta "one of the best roles for a soprano. It seems to be written for two or more kinds of voices - a challenge for one person, singing various different styles," she said. "It's a great story, besides the fact that the music is genius. . . . It's one of the challenges, to portray the character and her change and her growth and make it believable."

Shelton says his robust role is a welcome change from his typically Mozart-heavy repertoire. "Mozart's tenors are usually really wimpy," he said. "Alfredo is a kid, still, but he's incredibly jealous and has a short fuse. It's fun to play a bad boy, and it's fun to play someone with a little fire beneath him."

Verdi classic

* UTAH OPERA will present Giuseppe Verdi's "La Traviata" in the Capitol Theatre, 50 W. 200 South, Salt Lake City, Friday and Oct. 16, 18 and 20 at 7:30 p.m. and Oct. 22 at 2 p.m. The opera is sung in Italian with English supertitles.

* TICKETS, $10 to $62, are available by calling 801-355-ARTS or 1-888-451-2787, in person at the Abravanel Hall ticket office or the Capitol Theatre box office, or by visiting http://www.utahsymphonyopera.org. Subscribers and those desiring group or student discounts should call 801-533-NOTE.