If you're a musician in the Bay Area (and you're not a member of the San Francisco Symphony), the secret to success is to diversify. Whether it's new music, jazz, ethnic styles from around the world or around the block, if you can do it well, and authentically, you can not only have a career, you just might blaze a trail. Kronos, the Turtle Island String Quartet, and the Quartet San Francisco have all found ways to stretch the boundaries of what it means to be a classical string quartet; with The Real Vocal String Quartet, we may have finally burst those boundaries. San Francisco Performances is giving the Real Vocal String Quartet a chance to expand your idea of what a quartet can do on Wednesday, March 17 at 6:30pm at San Francisco's Hotel Rex.

The Real Vocal String Quartet was formed in 2003 by Irene Sazer, who had already diversified her career by playing with the likes of Ray Charles, Ella Fitzgerald, Frank Sinatra, and Linda Ronstadt, as well as with the San Francisco Symphony, the Oakland Symphony, the Baltimore Chamber Orchestra and the Women's Philharmonic. She was also a founding member of the Turtle Island String Quartet, which gave her a head start on building musical bridges. The other members of the Quartet, Alisa Rose, Dina Maccabee and Jessica Ivry are versatile veteran players with their own impressive and wide-ranging resumes. They've all got the classical bona fides, but they're also astoundingly fluent in jazz, klezmer, bluegrass, hip-hop, Brazilian, Balkan, Cajun, Middle Eastern, West African, and probably a dozen more musical languages.

Two things really set this quartet apart. First is their ability to improvise in any of those languages. Most classically-trained musicians are not taught to improvise -- they're taught to play what's written on the page as musically as possible. Improvisation is at the heart of almost every other musical tradition, though, and it takes a rare classical player to be able to break down those years of being true to the notes to let your fingers fly on their own.

The second difference is right there in the name. They sing -- while they're playing. As someone who has tried to sing with a viola stuck under my chin, I can tell you that it is not easy. Their voices fit together as well as their instruments do. Listen to their new CD and be very impressed. I certainly was.

RVSQ's music is by turns beautiful, haunting, mesmerizing and foot-stomping fun. There's a lot here that sounds vaguely familiar -- though I couldn't quite put my finger on the direct influences -- but for me the familiarity merely heightens the enjoyment of these mostly original tunes. There's even a cover of Paul Simon's "Night Game" (speaking of building musical bridges).

It's a show that will upend your notions of what a string quartet should sound like, in a setting that does the same for the notion of "classical concert." And it's St. Patrick's Day so you can count on a reel or two with some fancy fiddling.

The Real Vocal String Quartet plays the Hotel Rex on Wednesday, March 17, 2010 at 6:30pm. For tickets and information visit performances.org.