Conductor Daniel Spalding led the American Youth Philharmonic in a splendid concert at George Mason University’s Center for the Arts on Sunday. The event was free for people 18 and younger (although the parking fee was increased). Aside from Spalding’s opening commentary and pieces geared more toward adult listeners (the concert hall was only one-third filled), the afternoon gave the 129 student musicians opportunities to be featured either as soloists or as part of an individual orchestral section. And they did beautifully.

The program opened with two works of recent vintage: Miguel del Aguila’s “The Giant Guitar,” a busy yet beguiling essay curiously echoing Bernstein’s “West Side Story.” The percussion section seemed to have the most fun with a multitude of instruments reflecting the composer’s South American upbringing.

The group’s hard work also paid off in Mark Adamo’s “Four Angels,” a concerto for harp and orchestra, and Jean Sibelius’s Symphony No. 1 in E Minor, Op. 39. Dotian Levalier, principal harpist of the National Symphony Orchestra, starred in the concerto, as she had in its 2007 premiere with the NSO under Leonard Slatkin at the Kennedy Center. Adamo intended to reverse the traditional harp-orchestral role (the orchestra as central and the harp as decorative tracery) and have the harp lead, with the instruments only accompanying. To this end, Levalier summoned an unbridled impressionistic effect with a quiet luminosity pervading the orchestral texture. Adamo’s goal, however, was basically lost, for the orchestra favored fortissimos rather than playing second fiddle.

To cap things off, the Philharmonic tackled Sibelius’s lumbering war horse of a symphony — an appropriate teaching piece, for it exposed the young musicians to stylistic reminders of Wagner (Siegfried’s “Rhine Journey”), Dvorak (“Slavonic Dances”), and Beethoven (the 9th Symphony finale) all delivered in one package. The strings showed an amazing sense of ensemble and intonation. And Sae Hashimoto was a fabulous timpanist.

Cecilia Porter is a freelance writer.