During their first rehearsal of November, student musicians in the El Camino Youth Symphony shuffled with their instruments to join their respective sections, where they were each passed sheet music to Carl Maria von Weber's "Euryanthe" overture. It was the students' first time seeing their instrumental parts, but for the next three hours they would run through them together with hardly an error.

This year marks the 50th anniversary for the Palo Alto-based symphony, five decades of working toward achieving artistry beyond sight-reading alone. Under the direction of Camilla Kolchinsky, the group is now concentrating on readying for various performances later this fall.

"We're one amongst several youth orchestra-type organizations in the Bay Area. We're one of the largest, and we're definitely considered to be in the top echelon in terms of artistic achievement," said Cathy Spieth, the executive director.

The symphony's 500 students — who come from about 120 schools across the Bay Area — are grouped by talent rather than age. Its youngest students are in the first grade, and many play in ECYS through high school.

William Galbraith — a violinist raised in Menlo Park, who started off with the Stanford Symphony Orchestra in his high school years — founded the symphony in 1963 with a clear mission: providing young musicians the opportunity of performing a professional repertoire. This concert season, the organization celebrates its 50th birthday with what Spieth calls "signature favorites down through the years," pieces that "resound with the students and audience, and are a great joy to perform."

Senior Symphony Orchestra, ECYS' most advanced orchestra of its five orchestras and four ensembles, gathers every Sunday afternoon at Cubberley Community Center in Palo Alto. Most of its students also play in their schools' groups. When it comes to that, "we clear the way," Spieth said. "If there are any conflicts, we make it very clear to our families that school comes first ... and we've done our best to get that message to the schools."

ECYS' core mission of playing a strictly professional repertoire differs from that of most schools. Often the relationship is symbiotic: Students first pick up their instruments under the auspices of their schools, while the symphony strengthens the schools' leading performers.

And while orchestral music is the sole object of study, many students put their break time to good use, completing reading assignments or showing their bents for different genres of music. At a recent rehearsal, one clarinetist keeps a saxophone to practice jazz runs during downtime, while trumpet players project the theme to "The Lord of the Rings" in unison.

Coming up on the ECYS calendar is a Nov. 17 Palo Alto performance by Sinfonietta, the second-most-advanced orchestra. Two young soloists will be featured: clarinetist Alex Chang, and a cellist with an unusual background: Bennet Huang, who is also a competitive gymnast.

Currently in eighth grade at Jordan Middle School in Palo Alto, Bennet also takes part in gymnastics at a level that has earned him places on the National Gymnastics Development team in 2010 and 2012. He says he hopes to continue competing in college, and to make the Olympic team.

"Bennet is extremely talented and very musical, with innate leadership skills. Not only is he gifted, but he exemplifies the best characteristics of any team (orchestra) member: dedication, responsibility, a genuine love of music, and generosity. He is also a lot of fun, and during breaks, if you hear laughter, it is most likely coming from friends surrounding Bennet," Spieth said.

As for Bennet himself, he said that ECYS is "really fun." He added: "It's a good way to experience chamber music, playing together with other instruments. My older brother did violin. I did piano for a little bit and didn't really like that. Then I saw a cello and thought, 'Why not try that?'"

Asked if he had to pick between music or gymnastics, Bennet hesitated. "I have been asked that before. But I wouldn't really answer that. I'd keep both!" In his spare time, he enjoys classic board games and reading.

At the Nov. 17 concert, Bennet is scheduled to solo in Haydn's Cello Concerto in C Major, Movement 1, with Alex soloing in Weber's Clarinet Concerto No. 1, Movement 3.

Meanwhile, the ECYS Senior Symphony is preparing to perform its holiday concert on Dec. 9 at the California Theatre in San Jose. Besides featuring Weber's "Euryanthe" overture, the program will also include music by Debussy, Barber and Vieuxtemps.

ECYS has not gone through its 50 years unchanged. For Spieth, the anniversary occasioned research into the group's story and evolution.

"In the '70s and '80s, the orchestra shifted a little bit toward a more casual attitude," she said. "In the mid-'90s the board of directors decided that it was time to focus on the original mission of the organization, and brought on Dr. Kolchinsky. There's been a really successful return to the mission of offering excellence both in music education and performance." Kolchinsky's tenure has also seen a rise in enrollment: 500 students, up from 200.

"Over the last 15 years or so, the orchestra's been composed of mainly Asian-American students whose families place a high value on education including arts and culture," Spieth said. "If it were not for their value system, perhaps we wouldn't still be here."

To observe that diversity, the organization will put on its second annual Lunar New Year Concert next February, complete with festivities, a dragon dance and solo performances at the Flint Center in Cupertino.

Yet the organization's future is not assured, Spieth said.

"We used to receive significant funding from the state of California, and that has greatly diminished over the past eight years down to a trickle. We don't want to step away from the quality of the program, and we haven't. But every year it costs more to do the same thing," she said.

Last season, ECYS closed its books with a balanced budget. Funds consist of "about 60 percent earned income: tuition. We generally raise it about 10 percent every two years. Forty percent is contributed income: grants and fund drives," she said.

Much of that money goes towards renting practice spaces at Cubberley Community Center and public schools. Some is redirected to a financial aid fund for students. "We don't want to turn away any student," Spieth said.

Every two years, students and staff embark on an international tour. Next summer, the destination is central Europe. Students return with performance experience, though sight-seeing is also very much in order.

Other opportunities for students to bond include a season-starting retreat in August, with both rehearsal and social time. During the year, ECYS also hosts luncheons and receptions to help parents network and make friends.

For those students who continue to grow in their musicianship, there are steps beyond ECYS, including the San Francisco Symphony Youth Orchestra, a pre-professional training program for students of up to 21 years.

"We're really excited when our kids graduate from ECYS into San Francisco Symphony Youth Orchestra. If they get in it's a big deal," Spieth said.

Those young musicians also continue a long tradition of ECYS alumni who have gone on to play at their college and beyond. The group's very first concertmaster, Robert Galbraith, now plays with the San Francisco Ballet orchestra.

Info: ECYS' Sinfonietta Orchestra is scheduled to perform at 7:30 p.m. Nov. 17 at Spangenberg Theatre, 780 Arastradero Road, Palo Alto, conducted by Camilla Kolchinsky. The Senior Symphony plays its holiday concert at 2:30 p.m. Dec. 9 at the California Theatre at 345 S. First St. in San Jose. Tickets for each concert are $8/$15. For details, go to ecys.org or call 650-213-7111.