NEW YORK — Sometimes Vivica Genaux loves to sing with the precision and breakneck speed of an athlete — in "techno rhythm."
Other times, the tunes are achingly slow, but still bursting with passion.
The common thread of most of the songs she performs is that they come from obscure archives, silent for centuries.
The four-time Grammy-nominated mezzo-soprano is now taking some of the forgotten works by Vivaldi and others on a U.S. tour, in a program called "Pyrotechnics," after one of her albums.
"It represents fireworks, both the flashy, really fast-moving ones, and also the more delicate ones that glitter and fall like golden fronds," says Genaux, who is featured on Vivaldi's "Ercole sul Termodonte" ("Hercules in Thermodon"), which is up for a Grammy next month for best opera recording.
The tour, with Fabio Biondi leading his Europa Galante ensemble, starts Wednesday at Disney Concert Hall in Los Angeles a includes Las Vegas and Denver.
On Feb. 2 in New York, Genaux appears at Carnegie's Zankel Hall with the ensemble based in Parma, Italy — a few hours from the home near Venice she shares with her husband.
It's far from Genaux's native Fairbanks, Alaska, where she learned to drive her family's husky-drawn dog sled, and to change a car tire in 40 degrees below zero.
She's equally at ease in a Venetian palazzo, trying on a designer stage gown.
"In Italy, I learned how to be a girl," she jokes.
In Spain, where she sang a "pants" role — a woman singing a male part — "I learned how to be a boy."
And this fall in France, she'll tackle the ultimate "girl" part — Bizet's seductive 19th century "Carmen."
The 42-year-old singer is not as well known as her amazingly agile voice and musicianship deserve, perhaps because she has focused on the "Early Music" of the 1700s, with its special, smaller audience — for pieces often so fiendishly difficult that very few can pull them off technically.
But there's much more to it.
Works like Vivaldi's "Ercole" are "very modern, really," she says in an interview at the Manhattan home of her publicist. "The songs are about relationships between people, about personal contact, and that's the same now as it was 300 years ago, as it was 1,200 years ago!"
Vivaldi wrote "The Four Seasons," now heard in everything from ringtones to car ads. But many of his other compositions might have remained voiceless if it weren't for Genaux. With the help of musicologists, she's resurrected them along with forgotten pieces by Handel, Rossini and German-born composer Johann Adolph Hasse.
Leafing through his long-lost operas, "I got goose bumps just touching these manuscripts that were there since the 1700s," she says. "That's about 95 percent of what I do — pieces that haven't been performed since then."
It took years of soul-searching and experimenting for Genaux to figure out where her voice truly belonged.
At the University of Rochester in upstate New York, she majored in genetics, simply because she'd been surrounded by science as a child; her father was a biochemistry professor and her mother a teacher.
Music was a hobby.
Genaux played Eliza Doolittle in a high school production of "My Fair Lady," listened to ABBA's rock music and enjoyed Fairbanks' "sing-it-yourself 'Messiah' where you sang the whole bloody 'Messiah' — not just two pages of the 'Hallelujah'!"
Halfway through college, she switched to singing, transferring to the University of Indiana's arts school in Bloomington as a soprano, eventually becoming more comfortable as a mezzo.
In 2002 came her breakthrough — the Grammy-nominated album "Arias for Farinelli," the infamous "castrato" who was the rock star of his time, improvising on melodies as one does in jazz.
Farinelli's voice was a force of nature. And so is Genaux's, critics says.
"Onstage, she's a powerhouse," says David Shengold, a music critic who writes for New York-based Opera News and London's Opera, the world's leading magazines on the subject. "Her florid work — fast coloratura with clean runs, trills and wide, accurate skips — makes for bold, astonishing vocalism."
There's one quality that Genaux lacks, though: the elitism many people associate with classical music.
"Come, wear jeans, rip holes in the jeans, put on the worst pair of tennis shoes," she says. "But come and see ... come experience something new!"