Don't tell the Real Vocal String Quartet that they are "Feist's secret weapon," a label recently hung on it by a Paste magazine critic.

Sure, anyone who has heard the San Francisco-based group's music or its contributions on other artists' albums, including Feist's "Metals" recordings, will likely tell you that such praise is more than well-deserved. But the members of the RSVQ seem genuinely stunned by such superlatives, preferring to talk about the mission of their music.

"I just want people to be moved by our music," said composer, violinist and RSVQ founder Irene Sazer of what she hopes fans take away from the group's concerts. "It's such a tiny little answer but [our hope is] that our music has meaning for other people. That is what really moves me. I [play music] because it has meaning to me; we all do. To hear that somebody felt something or was swept away with beauty that inspired them, those are the kinds of things we love. "

Sazer brought the four members of the all-female group together in 2003. All classically trained, nationally renowned musicians, the two violinists, viola player and cellist routinely sing and string as they play their music, a mix of roots and world with more than a few accents of pop and blues.

The sound was developed in part as a deliberate attempt to break musical barriers that wall classical music off from listeners.

"There is a perception that 'new music' for classically trained musicians needs to be difficult or inaccessible," says violist Dina Maccabee. "We are all totally into challenging ideas but we also like pop music. And we feel like just because you have a highly trained skill set doesn't mean you need to play obscure music."

Although each member has played with a list of popular musical luminaries -- everyone from Bjork to Train to Vienna Teng and, of course, legendary orchestras and other groups -- the members sound as humble and enthusiastic as newcomers about having others discover the beauty of mixed-and-matched musical formats.

"Every single one of us had that drive and love of music to take it to an advanced level," Sazer said. "I was raised in L.A., so I was surrounded by the Beatles and Carole King and then also my mother was really into world music. I would listen to world music from the time I was a teeny-tiny kid."

Such early musical influences led Sazer and her bandmates to keep finding and sharing music they love through their own distinct sound.

"All of us keep discovering more and more and more [music]," she said. "That is one of the things that keeps us excited about the group and gives the group so much energy. It's endless."