YOU KNOW THAT cartoon strip about a day in the life of a one-note man? He gets up, has breakfast, buses to Carnegie Hall, unpacks his cymbals, waits and waits, finally CLASHes his note, waits and waits, paks his cymbals, buses home, has dinner and goes to bed.

It's not like that at all.

For one thing, an orchestra percussionist has to know 50 or 60 instruments and the different ways to strum, thump, rattle, shake, ring, brush, tickle, scrape and CLASH them. And all the crotchets: tympani like to be played two inches from the rim. Different kinds of sticks, from wire to rubber to wood to felt, make different colored sounds. Subtleties of dynamics and style must be learned, so that the triangle makes an exquisite honey-drop of sound and not a clang, so that the xylophone purrs with elegance and not the vaudeville clatter of a Professor Lamberti.

Tony Ames, with the National Symphony, started playing drums in high school in Pittsburgh mainly because his parents, both professional people, wanted him to go to law school. He insisted on entering Eastman, spent seven years catching up with other young musicians who had been at it since age 3, went to graduate school at Carnegie-Mellon.

"It's all solo work," he says. "You need good nerves. If your hands shake during the drum opening of Ravel's 'Bolero' it sounds like a rain forest. People try for variety in that passage, making it almost too soft to hear, using knitting needles, coins, fingernails . . . "

Some say that a percussionist's life, like war, is hours of tedium punctuated by moments of terror, but for a pro like the 38-year-old Ames, the symphonic Top Forty are so familiar that it is hardly necessary to count the endless measures between notes.

"What happens is that you get interested in other forms of music to help fulfill you as an artist, to improve your performing edge and sharpen your insights. I mean, it's one thing for the top musicians, but the guy back on the third desk of the violas can lose his commitment to art, his artistic vitality."

Which brings us, and none too soon, to the 20th Century Consort, an avant-garde music group founded by Ames to explore the vast New World of sound whose Columbus was John Cage.

"In the '60s we had an enormous period of experimentation. New ethnic resources, new instruments, electronics, odd combinations like cymbals played with a bow, the prepared piano, the vibraphone: a cornucopia of sounds. It went further in the '70s, with George Crumb's wild ideas for the prepared piano, sticking a pencil point into it and hitting it for a bell effect, or putting a cymbal on a tympani head. Or Joe Schwantner's work with fingers gliding along crystal, like a wet wine glass: He won a Pulitzer last year. Steve Reich and Philip Glass and others experimented with sound textures, tapestries that slowly shifted for color effects. You can produce an illusion of notes, ghost notes, harmonics, very ethereal effects."

The trouble was, most of this music was so cerebral -- reacting as it did against tired romanticism and antique instruments -- that audiences fled. The stuff was rarely played and therefore little understood.

"This lack of sensuality, no melody or harmony, alienated the public and brought few rewards to the composer," Ames adds. "But then sensuality came back, people started to dig it and combine sensual elements with their austere, abstract forms. And the audience came back too. I think we have the beginnings of a new style. There's still too much lag time before new works get performed, and orchestras don't know whom to program. But the word everyone's using today is: accessible."

This is where the Consort comes in. Its skilled musicians -- NSO veterans -- give new work the best shot it could get. With generous support from the Smithsonian's Division of Performing Arts, the group gives regular concerts and even tours. It also plays in the Millenium Ensemble's annual series at Martha's Vineyard, again thanks partly to the Smithsonian. The Ensemble's five chamber groups play, respectively, music from early 17th to late 20th century.

It may be the most important development since Cage first leaned over and strummed his piano strings: It restores a broken connection. The advance guard, after all, is still part of the army.