Anchorage Youth Symphony conductor Linn Weeda heard the violins flailing for their notes in Francois Poulenc's "Gloria" and winced.

"Ooh, that's out of tune," he said, folding a corner of the page in the score where the infraction occurred. "We're going to be working on that."

Poulenc's style melds sensual romantic lines with piquant modernist dissonances. Get it wrong and the listener wants to plug his ears. Get it right and it's like what angels must hear when they're standing in the air.

Weeda and the AYS really want to get it right. Not just because they'll perform the piece with the Anchorage Concert Chorus at the Alaska Center for the Performing Arts on Tuesday, but because they'll play it again in July for an international audience at the Sydney Opera House in Australia.

The AYS will be the guest of honor at the Australia Youth Music Festival, accompanying a choir drawn from the best voices Down Under. It's the first time the orchestra has traveled to Australia in more than 20 years.

"It's been a long time since we've done any international touring," Weeda said.

Perhaps that's for the best. "Twenty years ago, we couldn't have pulled off something like the Poulenc. It says something about the rising level of musical education in Anchorage."

The trip is tightly planned with little time for sightseeing or recreation. "We leave here, arrive in Sydney, practice, play, come back," said AYS general manager Ron Flugum. "It's a pretty bare-bones trip."

It still costs: $4,500 per musician for the nine-day excursion, money the students have been scrambling to raise for months.

But it's worth it, said flutist Anna Boslough, a sophomore at West High School. "I'm excited. They talk about these tours, but a lot of times they don't really work out. This one's going to happen."

A flute player can carry her instrument in her lap. It's tougher for musicians whose instrument is the tuba or string bass.

Flugum hopes to cut costs by renting larger instruments in Sydney.

"We still have two or three 'coffins' for double basses from the last trip there in 1985," he said. "It took a special crew of parents to move the harp. It'll be cheaper to rent them than ship them."

In addition to the "Gloria," the orchestra will also perform the finale of Beethoven's Ninth Symphony with the Aussie choir.

Organizers originally asked for the Beethoven to be paired with Mozart's Requiem. Weeda resisted because of the stylistic similarity of the two pieces and because the Mozart uses fewer instruments. "If we did the Requiem, a lot of our musicians wouldn't have anything to play," he explained.

The Poulenc deploys a vast array of instruments; everyone gets a chance to be heard. But stylistically it's tricky, and polishing the piece is made trickier in this instance by the fact that rehearsals with the chorus are limited.

"They're used to having more time with guest artists," said Grant Cochran, director of the Anchorage Concert Chorus. "To further complicate things, our only two rehearsals together will be in two different halls, halls that don't sound the same as the Discovery Theatre," where Tuesday's performance takes place. Cochran will lead that performance, in a sense a dress rehearsal for the Australian concert.

Cochran and Weeda and their groups collaborated in a program of music by Ralph Vaughn-Williams two years ago. The experience was highly satisfying, and both men wanted to do it again somewhere down the road. Preparing for the Australian tour provided an opportunity.

Because they're occupied with preparing for their own upcoming concert, the singers couldn't manage to fit in Beethoven's Ninth, but they did make time to learn the Poulenc.

On the street, the AYS players may look like normal teens, even if they have unique enthusiasms. Concertmaster Guerim Kim, a junior at West High, has an interest in medicine. South High senior John McKeever, who leads the string bass section, also plays jazz and likes to make video skits with friends.

But these teens may have more courage than others. Aside from the hours committed to practice and rehearsal and the efforts to raise the funds, there's the time and discomfort associated with a trip to the far shore of the Pacific Ocean from Cook Inlet. Just getting there requires a high degree of determination shared by musicians, their families, teachers, sponsors and the AYS board.

"Obviously, we didn't know the economy was going to go so sour when we started to plan this," Weeda said. "The board has put a tremendous amount of work into this."

"It's a stretch," Flugum said. "But everyone's being very brave."