Two hundred tubas of every shape and kind came together on the national Ellipse last night to bleat Christmas carols into men's hearts. Maybe you heard the noise in South Arlington.

The concert was not sponsored by the National Lampoon. In fact, it was a deadly serious -- some would say sublime -- concert, performed by area high schoolers and low-level bureaucrats with special poetry in their souls, all of whom seemed intent on setting the much misunderstood and ridiculed tuba in its rightful music heaven.

They called it "Merry Tuba-Christmas U.S.A." Sunday, there was a similar concert by a similar band of zealots at Rockfeller Center in Manhattan. This Thursday, there will be a Tuba Christmas in Los Angeles. Dallas has one Friday. What we may have here is a genuine tuba renaissance: tuba fever. Horns of plenty finally sticking up for themselves. r

Actually, you haven't Christmas-caroled at all until you've caroled over top an achingly insistent BLUUURP BLUUURP BLU-Bluurp, Blurp BLURP BLURP BLURP, which is tuba for "Joy to the world/the Lord has come." If you're a tubaphile, that sort of accompaniment can set you freer, make you believe in things.

Last night, such sounds wafted sweet as fog horns out over the Tidal Basin, curled subtly as smoke wisps up toward the remotely lit White House (What could they have thought in there -- that Sousa was marching on the lawn?). There was maybe 150 souls in the audience, sitting stoically on metal chairs, braving the Minneapolis-like temperature and Amarillo winds. Mostly, they were proud parents and delighted spouses.

"I don't think the Pentagon has that much brass," said a man borrowing an old tuba joke and lugging three kids. He listened rapt for a while, then went over and huddled by a pit of roaring logs. Though he was 70 yards from the action, he still hummed and nodded a merry time. His wife was up there somewhere on the stage, he said. The family had driven up earlier in the day from Virginia Beach to participate. "I play cello," the man said, a bit defensively.

You may not particularly be aware of this, but there is in America something called TUBA, which stands for Tubists Universal Brotherhood Association. The organization, 2,000 members strong, is every bit as fanatical for its instrument as barbershoppers are for their harmonies. It holds annual international meetings. Often they're in the fall. They call them Octubafests. Nobody ever said tubists aren't corny.

In fact, they seem wonderfully corny. The more you're around them, the more you sense a sort of liberated innocence. There's something also of what might be called joys of the ghetto: They know people are snickering. Last night, at five minutes to 7, all 200 tubists ran across 14th Street, causing an exotic traffic jam. Some of them went across chanting "Tuba. Tuba. Tuba."

In California there is a tubist (not to be confused with somebody floating down the Colorado on an innertube) who plays with the L.A. Philharmonic. His name is Roger Bobo. His license plate reads BOTUBA. People honk. He honks back.

More tuba lore: Composer George Kleinsinger, an American, once wrote a complete orchestral valentine called "Tubby the Tuba." It was about a tuba who felt left out by the other instruments. Kleinsinger, knowing a good thing, followed with "Pee-Wee the Piccolo," an instrument that has also suffered some neglect -- though it does get the high notes in "Stars and Stripes Forever."

It's odd, really, say tuba devotees. You just don't put your lips together and blow (as Lauren Bacall once said about whistling). The instrument is actually quite subtle, demands not only stamina but timing and grace. Tubists like to say the instrument is 95 percent flesh. It is one of only two solo instruments in the entire orchestral arrangement. (The other is the harp.) It can play as lyrically and nimbly as a flute or violin. Yet it has this big blowed image. Its detractors have said it sounds like mere flatulence. But on the other hand, Chaucer made art out of that.

"Pablo Casals or Valdimir Horowitz could have been tuba players," says Harvey G. Phillips, who is regarded as the world's best living tubist. "But if they were, nobody would have heard of them. Till recently, there was never any tuba literature."

Phillips, a distinguished professor of music at Indiana University, planned last night's show. He lives on Tuba Ranch. His three sons play the tuba. He has personally commissioned over 120 works for the tuba. He has been written up extensively in the New Yorker, among other places. Formerly, when he flew around the country giving tuba concerts, he used to buy the seat next to him for his instrument. It was a 1920 model. Now he has a new instrument and a specially built trunk. So he checks his tuba with his bags. And worries the whole flight.

Yesterday, before the concert, Phillips sat on a stage in the Department of Commerce auditorium. He spoke above the din of 200 tubas tuning up. You might have thought as many 747s were setting down at Dulles. Phillips is a great, rolly man with lips of pinkish aureole (dead giveaway of the horn player) and an undertaker's suit with subtle white piping. He is a man with a mission.

"In Prokofiev, the tuba player finds himself in an ensemble with bass, clarinet, flute, and violin. In Wagner, with a string bass section. Well, I don't despair of jokes about my instrument so long as I know things like that." In fact, he added, the tuba's potential range is quite amazing: It can extend from below the bottom of a piano keyboard up to an octave above middle C.

Though Phillips himself has been described as having hands like sausages and feet like gunboats, he insists a tubist needn't be large. Little wisps of humanity will do. "It's the size of the talent, not the person."

When Phillips goes on tour, his wife sometimes drives him. He sits in the back and practices. He is descended from poor, move-about, Missouri farm folk. Once he bleated in a circus. Later he went to Julliard on a scholarship. Nowadays he carries his own book of press clippings and has concerts in Carnegie Hall.

What may surprise is the diversity of backgrounds among tubists. Basil Wentworth and his wife drove in from Indiana for yesterday's concert. Wentworth, in his 50s, is a retired U.S. diplomat. He had assignments in Australia and Israel and other places. He quit and is now back on a college campus studying under Phillips, whom he calls the Moses of the tuba renaissance.

"I was very serious about the instrument when I was in high school," Wentworth said. "That was 100 years ago. I'm trying to recapture my old lost form."

Just then Wentworth was interrupted by the program's conductor, Dr. Frederick Fennell, who was calling for a final run-through of carols.

"There will be enough of us here," said Fennell, "so that if we reduce our volume by half of what we think it should be, we will have a beautiful singing sound . . . If we do not reduce the decibel level, we may have a monster out of control."

What followed was not exactly a monster on the loose. More like an Irish orchestra -- every man for himself.