The D.C. Youth Orchestra Program is 20 years old this week, which is older than nearly all of its members, some of whom are smaller than their instruments.

Around its fringes, hurricanes of controversary have huffed and puffed: School officials have accused it of playing "European music" -- meaning Bach, Beethoven and Mozart. It has been called "elitist" -- meaning that it pursues excellence. Some have complained that it is too white, but staffers reply that it is 90 percent black throughout. In the past, school boards have fought for whole evenings over their $150,000 contribution to the program -- a tiny fraction of their budgets.

There is plenty of electricity inside the program too, but it is a different kind.

Concertmaster Philip Swaby started playing a half-size violin when he was 7. A couple of years later he joined the elementary orchestra, set in the last chair of the second violins. Now he is 17, the head violinist, the chief musician of the senior orchestra.

"Practice? Oh yeah," he laughs. " I have rehearsals half the day or nights of the week. But I get in at least three hours a day practicing. Of course, when you're working on an orchestral piece it's a lot simpler. If you go through the piece three times, that's three hours."

Lisa Ferebee is 19, a cellist who has graduated and now studies in New York with David Sawyer of the Guarneri Quartet.

"Practice? Oh, four hours a day. I've never been interested in anything else."

Sally Stout, 20, University of Indiana, a violinist who was concertmaster with the Youth Orchestra for three years: "Sometimes I'd practice so long I didn't have time to do my homework. Who wants to do homework?"

Last weekend, as the week-long anniversary celebration started -- the climax is tonight's gala concert at the Kennedy Center at 8:30 -- founder and director Lyn McLain brought some of his alumni together as an impromptu string quartet to play at a press party. He asked 20-year-old Tracy Inman to take the second violin part because "Tracy's got a lot of other things going, he's learning marketing research and he does modern dance at the Dance Place, and I think he's been letting this slide a little, and I wanted him to see that he can keep up with the others and should stick with it."

That's just like Lyn McLain. Even after 20 years, he seems to keep tabs on all his kids, to know what they're doing with their talent, to have ideas for them. He's the kind of teacher that happens to you maybe once or twice in your life, they say.

Basically a clarinetist, he has played classical and jazz. His compositions and arrangements have been used by dance companies. After some years free-lancing as a performer, arranger and composer in New York, he came to Catholic University for some more graduate work in composition, wound up teaching music at Coolidge High School.

"The kids wanted to learn drums or tenor sax or something," he said. "They wanted to be in the stage band I started. I played in it too. We built up a 65-piece orchestra there. There's so much commercial pressure on schools to concentrate on marching bands and spend all the music money on uniforms and stuff instead of instruments."

Pressure or no, the program is doing just fine. Some 800 students from 7 to 19 come to Coolidge three days a week from all over the Washington metropolitan area to play in one of the three orchestras or three concert bands (elementary, junior and senior) or a variety of chamber groups and wind ensembles.

The 40 or more teachers provide free instruction on instruments loaned for $30 a school year. The same teachers circulate among 21 D.C. elementary schools in a separate program that is part of the basic contract between the Friends of the Youth Orchestra and the school system.

There is also a free summer school five days a week June 29 to Aug. 7 at Coolidge, for which registration starts June 24.

The emphasis is always on performance. The orchestras play at least once a week, at Lisner Auditorium, at schools and hotels and hospitals all over the area. Including the smaller groups, the program generates hundreds of concerts a year, McLain says.

How is all this possible on $150,000? It's not. The story of the Youth Orchestra is the story of a 20-year tightrope act. It costs in all about $350,000 to run, and this is where the Friends come in. There have been some exciting moments.

"We have 14 concerts lined up in Greece and Israel," McLain says. "We'll stay at some kibbutzes among other places and perhaps do a concert with an Israeli chorus." The trip is set July 30 to Aug. 21 for a group of 75 people including 67 musicians.

As for the "European music," it is true the repertoire ranges from Beethoven's Ninth and Mahler's Fifth (which wowed them in Scotland, competing with much older groups) to Offenbach, von Suppe and so on, but the orchestra has commissioned and premiered many American works, especially by blacks. George Walker, a Washington native, gets regular hearings, and in '73 Mark Fax's opera was premiered here.

But the real accomplishments, after all, are the students themselves. Julie Bogorad, a 1972 graduate, is first flute with the St. Paul Chamber Orchestra. Jamie Kowalski, at 17, heard his First Symphony performed at a music festival in Bulgaria last year. Michael D. Morgan ('75) took first prize at a conductor's competition in Vienna. He has already been an apprentice conductor for the Buffalo, N.Y., Philharmonic and the St. Louis Symphony. John Williams, also '75, was 1980 regional finalist in the National Black Music Colloquium here.

Lyn McLain could be proud.