Sergio Assad is in an airport, taking a call from an interviewer on his cell phone. All except for the cell phone, he probably knew even as a teenager 35 years ago that he'd be doing this often.

		Sergio and Odair Assad Where: Synod Hall, Oakland, presented by the Guitar Society of Fine Art. When: 8 p.m. Saturday; pre-concert reception at 7:15 p.m. with the Chien-Rainey Guitar Duo and Marco Sartor. Tickets: $25; 412-394-3353. Listen In Listen to excerpts of performances by Sergio and Odair Assad: "Escalaso" from "Suite Troileano" Gigues 1&2

Back in Rio de Janeiro, his guitar teacher laid out the future for Sergio and his brother, Odair.

"She tried to put it in our minds that if we wanted to play the classical guitar, we had to try to push an international career. That was our goal from the beginning. Because in Brazil, especially regarding classical music, the market is very poor. So we knew that we had to leave.

"You know, the guitar circle exists -- it's not huge, but exists spread out, so you'll find guitar admirers all over. So in each country they have their small community and they organize concerts, and you can have a career."

Saturday night, their career brings them to Synod Hall in Oakland, as guests of local guitar admirers the Guitar Society of Fine Art.

The buzz on the brothers is that they make two guitars sound like "one bigger guitar," as Sergio puts it. He attributes this to their playing together since they were barely bigger than a soccer ball.

Bergio and Odair were born in a small town in southeastern Brazil. Their talent was nurtured by their watchmaker/mandolin-playing father, who found a teacher for them in Rio (Monina Tavora) and moved the whole family there.

After winning a prize at a competition in Bratislava in 1979, the Assads duo took off, with concerts around the world, and recordings including a rendering of European harpsichord music that magically summons up the guitar's plucked distant cousin, and a moody, sensual collection of tangos by Argentinian composer Astor Piazzolla. In 2004, they performed with Yo-Yo Ma on his "Obrigado Brasil" CD, giving them an even higher profile.

On his cell phone, heading back to Chicago after a trio gig in Boulder with violinist Nadja Salerno-Sonnenberg, Sergio explains it's the brothers' differences that forged such a strong amalgamation.

"We have a very different knowledge, and we have a very different approach to the instrument. I think our personalities and the way we deal with the instrument and with music, they somehow combine and make a unity that is bigger than I or bigger than he is. In that sense, I don't think perhaps that we could have had a solo career, each one of us, but we sort of put all the bets on the duo from the beginning."

Sergio's role is arranger, composer and second guitarist. That's because Odair, his younger brother by 3¹/₂ years, "is a phenomenal player," he says. "There are very few people can play the guitar like he can. And we wanted to play together from the beginning, so I started from the beginning to create second guitar lines for his 'voice,' let's say. So that helped to shape my skill as an arranger, as a composer."

As for sounding like one instrument, Sergio explains it this way: "If you want to create any kind of chamber music, you have to develop a unique mind, in that you have to do the same articulation, the same dynamics -- you're playing together. What we added on top of that is a sort of feeling or a belief for shaping dynamics, shaping phrasing, that is very similar. Now it got very similar because we played together for so many years."

The Assad Brothers are part of a larger musical family. In the summer of 2004, Sergio and Odair went on tour with their parents, children, and younger sister Badi, a guitarist/singer whose innovative style includes mouth percussion. Sergio's daughter, Clarice, is an award-winning classical composer, as well as a jazz singer and pianist. His son Rodrigo is an aspiring movie-maker, but he also plays guitar and writes songs. The Assads' mandolinist father and vocalist mother had never stepped on a stage professionally before the tour.

"And it happened that our mother was a sensation. Everybody loved her so much that she is putting out a record in Brazil. She's 75 years old. Lots of known artists are participating on her recording. She's sensational."

Odair lives in Belgium, while Sergio moved from France to the States a few years ago, where he has been teaching at Roosevelt University's Chicago College of the Performing Arts. But the brothers have been so busy since their collaboration with Ma that Sergio took a leave of absence. 2006 has been "totally insane, we didn't stop for one minute. So I asked to be away until my life gets back to normal. But for the time being I just play, and I'm writing a lot, actually."

Here in Pittsburgh, he says, the brothers will probably start their concert with some harpsichord pieces by Rameau, then continue through the Spanish composer Joaquin Rodrigo, Piazzolla, and some pieces written by Sergio and other Brazilians including Egberto Gismonti, Radames Gnatalli and Villa-Lobos.

As if to prove that two guitars can function as one instrument, the duo has been known to do an encore where Odair holds the guitar and Sergio leans in to join him on a four-handed piece. Will they do that Saturday night?

He laughs. "We're getting too old for that. I mean I am getting too old. Because I am the one who has to lean over. For my brother it doesn't change much. But for me it does. I have to curve and do a little stretch. I don't know. We might."