Almost 8:30; Harold Boxer paces nervously up and down the marble floor outside the Hall of the Americas, under the flags of 26 nations of the Western Hemisphere, waiting for the last-minute crises. He knows they will come; this is his 10th Inter-American Music Festival, and they always have.

Tonight, they are small crises. A technician from National Public Radio comes out from backstage, his behind-the-scene blue jeans contrasting sharply with Boxer's out-front tuxedo."How long can you hold it? We're having some trouble with our board."

"You have at least five minutes," Boxer assures him, and the technician goes back to tape the program for later broadcast.

Technical problems conquered, the music begins: Julia Stilman's "Cantares." Soprano Myra Merritt spins out a melodic line: pure silver. A chorus of six sopranos elaborates it, and a small instrumental ensemble weaves in threads of impressionistic sound, the angular melodies and harmonies of a post-tonal idiom softened into a hymn of mother-love.

The festival is well underway.

Boxer readily accepts the title of "shoestring impresario." "I am the impresario who also sweeps the floor, sets up the chairs, arranges the stage and plugs in the organ. The festival has no paid staff, including myself; that makes it easier when I go out and beat the drums for it and they ask to see my financial sheet."

He has been working for the festival since it was begun 21 years ago by Guillermo Espinosa, who was then head of the music division of the OAS, and he has had total responsibility since Espinosa's retirement a few festivals ago. Originally spaced at one every three years, the festivals are now annual ("believe it or not, it's easier to raise money if you come around every year"). In 10 festivals, more than 200 compositions have received world premieres, and looking back you can trace the trends of a musical generation. Today, the trend is toward less experimental, more accessible music.

In the coming week, there will be six free concerts in the Hall of the Americas, the Kennedy Center, the Library of Congress; several world premieres, a lot of unjustly neglected modern music, a few older pieces that range from a violin sonata by Artur Schnabel to a piece of pure 16th-century Spanish polyphony from the Cathedral of Mexico City.

The first concert ends on a strong note: the Missa Afro-Brasileira of Carlos Fonseca, with vivid folk idioms smoothly adapted for church use. Amid the applause, an unobtrusive figure slips to the entrance of the hall: Boxer retrieving unused festival programs. They will be usable for tonight's concert at the Kennedy Center.