In recent weeks, the music of Beethoven and Tchaikovsky has been emanating from the back room of a Leesburg martial arts school on Friday evenings. Its starts and stops are indicative of young musicians hard at work for a big performance.

These students from the Little Mozart Academy, who usually rehearse in more cramped quarters upstairs, are preparing to host Loudoun's County's first international gathering of youth orchestras.

The week-long festival begins in Leesburg on Wednesday, uniting 100 young musicians from France, Germany, Mexico and Venezuela with 100 Americans in a combined youth orchestra. The gathering culminates in two free performances during Independence Day weekend: a gala concert at Potomac Falls High School in Sterling on Saturdayand a community concert at Franklin Park in Purcellville next Sunday.

The programs will include Tchaikovsky's "1812" Overture, Mozart's Overture to "The Marriage of Figaro" and selections from Rimsky-Korsakov's "Capriccio Espagnol" and Bizet's "Carmen."

The idea to organize such a gathering came to Gabriela Morillo Bohnett, Little Mozart Academy's founder and violin teacher, during a week-long trip to Orizaba, Mexico, in December for a children's orchestra festival. Mexico's national youth orchestra coordinating agency, Conaculta, invited Bohnett after learning about her academy through a former student who had moved to Mexico and joined the Orizaba orchestra.

Bohnett's chamber orchestra was the first American group to be invited to the annual Gathering of Youth and Children's Orchestras. Though the invitation arrived only a month before the event, Bohnett and eight students, along with several parents and siblings, signed up for the trip.

"It was really great," said Bohnett, 28. "Some of them had never left the country and got a chance to travel abroad with the orchestra to perform."

The Loudoun musicians joined the 200-member orchestra of young Mexican musicians for three days of rigorous rehearsals.

"The practicing was really hard. They had different conductors for every piece, and I was used to Gabriela conducting all the pieces," said Alicia Potes, 13, concertmaster of the academy's chamber orchestra.

Her brother, cellist Daniel Potes, 10, didn't mind all the rehearsing. "It was fun because my stand partner was really nice," he said.

For Bohnett, the Mexico trip brought back memories of her childhood in Venezuela, where she attended similar gatherings at least four times a year.

"I thought, 'I grew up with this, why haven't I done this in Leesburg?' " said Bohnett, who came to the United States 10 years ago and is working toward her master's degree in education.

The Fourth of July would be the ideal time to host an international gathering in the United States, she thought.

Bohnett had no idea where to begin, so she sat down with the Orizaba festival organizer for guidance. On the journey home, she announced her plan to the families and students on the trip.

"She said that she had been awake all night, planning this event. She had already given thought to the music, the time of year," recalled Dana Huggins, a parent of an academy violinist. "And I said, 'You want to do something on this scale as soon as July? Maybe we should push it off until another year.' "

Bohnett said many parents thought her plan was overly ambitious. Though she had built her music school from scratch, she had never organized a music festival. But she soon persuaded them that the academy needed to provide such an experience for its children in the same manner that the Mexicans had done for theirs.

"These people are in a country that is underdeveloped. They live through much more hardships than we do. And they can provide this for their children and ours. Why can't we do it? We are privileged to live in a more developed country and have easier ways of life, so there is no reason why we shouldn't be able to pull this together," she recalled saying.

Bohnett set her plan into motion by establishing the nonprofit Youth Music Preservation and Promotion Association to handle the fundraising side of the festival. She sent invitations to colleagues at European and Latin American conservatories. With the help of some academy parents, Bohnett began contacting local businesses for sponsorships and hunting for festival venues.

Originally, Bohnett had wanted the entire gathering to take place in Leesburg. But finding venues during Independence Day weekend proved to be a challenge. She also had to find rehearsal space for the expected 200 musicians and petitioned the Leesburg Town Council, which contributed more than $1,500 for rehearsal space at Ida Lee Park Recreation Center.

"From the beginning, I felt it was something we should do," said council member Fernando J. "Marty" Martinez. "I saw this group trying to organize something international that benefited children. It was one facet that was coming to town that we couldn't ignore. How could we not do something for them?"

Because the nonprofit association is in its inaugural year, many arts organizations could not approve contributions or grants for the festival. As a result, Bohnett and most of the academy families are opening their homes to host the international students.

"We want to show hospitality to those families because we were shown such great hospitality when we went to Mexico," Bohnett said. "The American families are making great sacrifices because a lot of families had plans to travel. And they have made arrangements to be here, and to work, really, that whole week prior to July 4th."

Some families were so impressed by the scope and philosophy of the event that they volunteered to help even though they have no children in the academy or festival.

"Getting kids together from different cultures and playing together is really terrific," said Lisa Mattia, 39, a general manager with Phoenix Productions, a Frederick company that puts on Broadway-type shows. "It's a pretty huge undertaking. And I think it's really neat, which is why we called in the first place."

She and her husband are among the many local families -- some in Arlington, Falls Church and Maryland -- who will provide room, board and transportation for the international guests during the gathering. They will host two French students and a chaperon at their Leesburg home.

The international students begin arriving Monday. Most of them have never visited the United States, so Bohnett has planned a day-long field trip to Washington. But most of their time will be spent rehearsing and performing under six conductors representing nearly all of the participating countries.

About one-third of the Little Mozart Academy's 130 students are taking part in the festival.

"I think it'll be really fun to have a chance to work with different conductors conducting different songs and seeing how they envision the piece," said violinist Linnea Morgan, 11.

Having missed out on the Mexico trip, Morgan said she was excited to be part of a festival similar to the one she had heard so much about. Her family will host musicians from Venezuela and France at their home in Purcellville.

Though he was part of the delegation to Mexico, violinist John Huggins, 12, was happy to have another opportunity to mix with international musicians. "It's going to be neat to play with people from all over the place," he said.

Students from local youth orchestras and even adults from local community groups will participate in the gathering. For the concert Saturday, members of the Master Singers of Virginia, Loudoun Chorale and Shenandoah Arts Chorale will join the orchestra for a performance of Beethoven's "Choral Fantasy," featuring Mexican pianist Daniel Villegas, 33.

"It's a very big piece," Bohnett said. "It's the hardest of the ones we're playing."

It's also one of the most anticipated pieces on the program, according to several young academy musicians. So far, they have rehearsed it with the academy's youth choir and a handful of extra players. Many of them can't wait to hear what it will sound like with the pianist, choristers and orchestra in place.

"Just the excitement of this happening and [what] this means for all my students and for all the other children that are going to be joining us, I just can't wait for them to experience it," Bohnett said.

Gabriela Morillo Bohnett, founder of the Little Mozart Academy in Leesburg, has organized a youth orchestra festival that will include musicians from France, Germany, Mexico, Venezuela and the United States.Mary Margaret Pagington, 9, rehearses at the Little Mozart Academy. Lya Yamanaka, 11, practices for the festival. Area families will host their foreign counterparts.Bohnett was inspired after attending a children's orchestra festival in Mexico, and she organized the Leesburg event in a relatively short time.