Her band, quirkily named the Fishtank Ensemble, plays Roma-influenced folk-jazz that sounds lifted from a Gypsy caravan that's set up on the edge of a rural Bulgarian village. And with a name like Ursula Knudson, it would seem natural to assume that the lady who sings for Fishtank Ensemble would sound like a caricature from a 1950s vampire film.

Such an assumption, however, would be wrong.

“I'm from Sacramento,” Knudson told The Daily Times this week. “I'm a California girl, but it is kind of funny when they think that.”

As with many things in the world of Fishtank Ensemble, things aren't always what they seem. Based on the West Coast, the band is making its first foray into the Southeast, including a stop at Barley's Taproom in Knoxville's Old City next week. And while the band's brand of music isn't textbook rock ‘n' roll, other blue-collar American cities have embraced the frantic energy that surrounds a Fishtank Ensemble live performance, Knudson said.

“Really, it's not a big deal,” she said. “Whenever we've played smaller towns in the Midwest or places like Frankfort, Ky. — where we've been before — we find that people just appreciate good music, especially if they can dance to it.”

The band's roots date back to 2004, when the core members came together at an Oakland, Calif., venue known as the Fishtank. At the time, Knudson was a trained opera singer; her husband, a native of France, is the band's violinist, Fabrice Martinez. Raised by bohemian parents, he spent his teen years traveling, including a chunk of time among the Roma people — Gypsys — of Eastern Europe.

“He had been all over Europe and started teaching me some songs,” Knudson said. “I don't have any personal experience traveling around listening to music like this. I learned from the people in my band, and the stuff I did learn from them is really fun to sing and play, because my personal style is so different.”

Together with flamenco and Gypsy-jazz guitarist Doug Smolens and bass player Djordje Stijepovic, Martinez and Knudson released the album “Super Raoul” in 2005. At first, the band's reach was limited to California; after the release of “Samurai Over Serbia” in 2007, however, the band began to branch out, gradually trending east and booking dates in Europe as well. For a time, Martinez and Knudson lived in Italy, where the latter sang opera and learned a number of different languages that she puts to good use on Fishtank Ensemble recordings.

“We play Serbian music, Romanian music, flamenco, the Gypsy jazz of Django Reinhardt — the type of music we play comes from all over Europe,” she said. “We attack these forms because we're interested in all of it. We write our own songs, but they're all loosely based in these folk traditions.”

The Roma people, she pointed out, still face a great deal of racial prejudice in Europe, but there's no denying their skills as musicians. For Fishtank Ensemble, adding little flourishes of American music here and there gives the band's sound a distinctive flavor that conjures up images of Squirrel Nut Zippers crossed with the local klezmer ensemble Tennessee Schmaltz.

Next month, the band will release a new album, “Woman In Sin.” As flavorful as “Samurai Over Serbia” was, the new record possesses an intensity and focus that comes across as even more flamboyant and celebratory.

“Before, I think we were a group searching for its sound, like we had been thrown together accidentally,” she said. “Now, we've all decided that even though we're differing personalities, we can come together on what we want this album to sound like. We sort of made up our mind that we wanted to use ‘Woman In Sin' to present ourselves to the world for the first time. Now, our sound is more definitive and not as random as we used to be.”

That still doesn't mean Fishtank Ensemble is for everyone. Knudson giggles when relaying the story of a newspaper editor in Frankfort, Ky., returning “Samurai Over Serbia” to the band's publicist, who thought the editor's response too humorous not to pass along to the band.

“He said, ‘That's the strangest damn thing I ever heard,'” Knudson said with a laugh.