AT NOON today, WETA-FM listeners can become ear-witnesses to the birth of a notion. The first sounds they hear will be an orchestra tuning up, followed by Firesign Theater alumnus David Ossman intoning in stereo grandeur, "Welcome, we're glad you've tuned us in. This is 'The Sunday Show.' "

"The Sunday Show," broadcast live by satellite, is National Public Radio's five-hour high-tech venture into arts programming, a somewhat high-brow companion to "All Things Considered" and "Morning Edition." It will be a potpourri, a kaleidoscope, a "magazine of the arts" with an emphasis on classical music but with forays into theater, dance, sound poetry and popular music.

Today's premiere, following four weeks of un-aired pilot programs, will include the beginning of the complete Beethoven piano sonata cycle recorded at the Kennedy Center and a preview of next week's 10-bell peal from the National Cathedral; a sound portrait of Andres Segovia; a report from the recent Humana Festival of New American Plays in Louisville, Ky.; an interview with television's Milton Berle and a behind-the-scenes look at the Dallas Opera Company's revival of Verdi's "Ernani." And to show off the programmatic reach afforded by NPR's satellite capabilities, there will be live transcontinental concerts featuring chamber music ensembles in Denver, Boston, Cincinnati and Seattle.

According to John Bos, NPR's director of arts and performance programming, "The Sunday Show" "really started in September of 1979 with discussions about rethinking classical music in terms of programming, how to get away from the imitation of being in the concert hall. That's not a real-time use of radio. Eighty percent of the stations in the NPR network can be classified as classical or fine arts formats, so we focused on those."

"We're trying to make a really accessible program," Bos adds, "and we're banking on the fact that there is an audience out there with a more eclectic appetite than one would think in terms of narrow-casting opera here or chamber music there. There has been some skepticism on the part of station managers as to whether that can be changed, but the arts folks all think we can do it."

Despite a stunning 40 percent listener gain last year, much of the NPR network has had to combat a stuffy, intellectual image. A number of stations are holding off, nervous about expanding their traditional programming boundaries. "The Sunday Show" team is planning to combat all that, hoping that a little bit of mixing and matching in the arts will attract new listeners, particularly those under 35.

Ossman, who signed on as executive producer and saw his role expand to include hosting duties, confirms that "the challenge seems to be to make the show acceptable to member stations because it will probably be a departure from what they're doing. Most NPR stations don't program eclectically at all, they program in tight formats. What's needed is to bring this kind of programming to different people, to people who are not now listening because they're alienated by the whole way it's presented."

For Ossman, there's a slight irony involved. When he started out in radio 20 years ago, it was as a classical announcer (it shows in his perfect pronunciation of foreign composers' names). A dozen years of aural pioneering via Firesign's convoluted comedy have convinced Ossman that people can change the way they listen. "In Firesign, we proved that you can do a very dense and compact piece of work that is still funny, that people can enjoy on many different levels and listen to over and over again. It moves in all dimensions--that's just pure audio. This is too."

Operating on a start-up budget of $750,000 (which will jump to $1.2 million next fiscal year), Ossman and Bos have put together a staff of 20. With the exception of Fred Calland, all are under 35. "And most are under 30," Ossman adds. "Do they listen to NPR stations? Probably not, because those stations are not very interesting to that demographic. Why shouldn't they be? Why shouldn't NPR lower its demographic? It can only benefit from expanding its audience.

"It's in my nature to push against people's conservatism," Ossman says. "They told me this would be an arts magazine; that means we include all the arts. If they'd said this was a classical music program, I wouldn't have been interested. It means we do things slowly, in terms of features rather than performance, but people's ears will open up, they'll hear more than one thing. Those people who don't want to hear anything about anything won't listen. Who cares? If that's your base listening audience, you've got a problem anyway."

In some ways, "The Sunday Show" will provide a much needed service for NPR member stations, 135 of which have already signed up for the program. It will be broadcast live in separate but consecutive segments of three and two hours (WETA will carry the entire program live from noon to 5 p.m., while WAMU-FM will carry the two-hour segment from 10 to midnight). "Sundays are a lean time for a whole lot of stations," says John Bos. "They're light in personnel and they're used to running programming from elsewhere there. It's a welcome thing to just be able to flick the switch to satellite transmission."

NPR will tape repeat "The Sunday Show" segments so that each of the four time zones can get all five hours (87 of the 135 stations will carry the complete program). Admittedly, no one expects listeners to stay tuned for the whole five hours "unless they're bedridden," Bos says. But the production is geared to sustain listeners through quality performances and an eclectic mix of news features and interviews.

"Radio is interactive to people's lives," Ossman insists. "At its best, you listen to it; at its least, it's background. Listeners tune in and out depending on what they like. If they like the station, they leave it on. If the program you're listening to is always changing in front of your ears, and you know from experience that in another 10 minutes you're going to be hearing something else, then you hang in there. It keeps listeners, rather than alienates them."

Although performance remains at the heart of "The Sunday Show," there will also be arts news and features. "For instance, we started tracking the issue of why there are so few American conductors fronting American orchestras," Bos says. "We talked to William Schumann in New York and Leonard Slotkin of the St. Louis Symphony. What is the problem with our musical environment that has to have Lorin Maazel obtain a reputation in Europe before he can get the Cleveland Orchestra?"

The challenge will be in coverage of non-sound oriented arts. "How do you do dance on the radio? How do you do paintings?" Bos asks. "If they don't have their own intrinsic sounds, then one hopes you can find someone intelligent and engaging to somehow discuss it." Those people will include Fred Calland and Connie Goldman, NPR veterans who will be allowed more space and leeway in their examinations of the creative process. Arts and humanities reporter Goldman has already completed interviews with actress Claudette Colbert, poet James Dickey, artist Roy Lichtenstein and playwright Arthur Miller, while Calland will dip into his extensive collection of audio artifacts for his "Crazy Quilts" spots.

News segments will be able to run much longer than they do on "All Things Considered" or "Morning Edition"; they'll also be in stereo, a marked contrast to the mono of the news shows.

The quality of performances will also reflect NPR's state-of-the-broadcast-arts capabilities. The concert lineup is impressive. The Beethoven sonata cycle recorded at the Kennedy Center, featuring such pianists as Rudolf Firkusny, Emanuel Ax and Ruth Laredo, will thread its way through "The Sunday Show," culminating with Beethoven's birthday in December. When the Concertgebouw tours America as part of the Dutch-American Bicentennial, "The Sunday Show" will either tape or livecast all three of their programs from around the country. There will also be coverage of international events such as the Tchaikovsky piano competition in Moscow, the Ludwigsberg Castle Festival in Germany and the International Guitar Competition in Paris.

One concern was whether the "Sunday Show" would reinforce the influence of the Boston-to-Washington arts axis. "NPR sounds too much like that anyway," Ossman says. "That's a long-standing West Coast objection; it sounds like it's all Eastern Seaboard. As a matter of fact, their hiring me helped influence an NEA grant because it was proof that it wouldn't be terribly eastern-oriented."

"The Sunday Show" will be radio's first national showcase for the arts, but it also continues NPR's concern with the idea of a national radio system. "There's no question about the importance of state-supported radio and radio orchestras," Bos says. "We're the only country without a radio orchestra, for example . . . We're way behind in providing American performances overseas. We take so much European stuff through our membership in the European Broadcasting Union. We feel kind of nationalistic in getting our stuff exported the other way."

Considering the cutbacks in arts funding, isn't it a strange time to be launching such an auspicious venture? "It's precisely the time to do it," Bos insists. "If this program achieves even half of what we want it to do, it'll be a real audience builder for the stations. And building audiences builds pledge support. And certainly the arts people feel that the pipeline this will afford them comes at the right time because they're getting crunched. It's a risk, but it's the thing to do instead of turning your tail and running."