SIR HENRY IRVING, the actor/manager best known as the recurring butt of Bernard Shaw's critical jokes, was once informed at intermission that his audience wasn't enjoying the play. "What a pity," said Sir Henry. "Because this is what they're going to get."

Zelda Fichandler, the producing directer of Arena Satge, loves that story. Not that she enjoys the cruel and unusual punishment of audiences. But after three decades of arduous effort and mounting national and international acclaim, she has become resigned to a certain Recognition Gap on Arena's front doorstep.

"I think Washington does love us," she says. "But there is a lack of recognition of exactly what kind of animal we are, and how we're different from another kind of animal that resembles us."

"The Arena company," she said after a State-Department-supported tour to the Soviet Union in 1973, "is more highly acclaimed and more accurately perceived in Moscow and Leningrad than it is in Washington or New York." In Moscow -- where there are 30-plus theaters of Arena-like (or greater) proportions -- "it was hard to explain that this was not the normal thing in Washington," she says.

The normal thing, when Americans refer to a "theater," is a building into which strangers -- often from New York -- are periodically invited to stage entertainments. Thirty years ago, Zelda Finchandler was one of the first people to question this definition and suggest, by example, a new one. The process has come a huge distance. Minneapolis, San Francisco, Louisville, Providence, Los Angeles and Boston are just a few of the cities that now possess what Fichandler has dubbed a "whaddaya-call-it" theater -- that "wee beastie wearing the hat bizarrely labeled . . . the Regional/Resident/Repertory Theater of Ameria." And in all of those theaters, in all of those cities, there is a sense of Arena as somehow "central, prototypical," as critic and theater historian Julius Novick puts it.

Other people are less circumspect. "It's the best -- absolutely," says Edwin Sherin, Arena's resident director in the mid-'60s and now the artistic head of the Hartman Theater in Stamford, Conn. At the Hartman, he says, "I don't have the logistical support that I had at Arena, and I don't have Zelda Finchandler. That lady is a natural resource. She's an extraordinary producer."

But to the general theatergoer -- to say nothing of thegeneral public -- the whaddaya-call-it theater is "still a new kind of thing," says Finchandler. As Arena celebrates its 30th anniversary (with the opening of the Bertolt Brecht/Charles Laughton "Galileo" Thursday night, followed by a reunion gala), it can claim unambiguous preeminence among its brethren in scale, quality, influence and continuity. But who has time to boast? There are three spaces to fill, an ever-increasing budget gap to close and -- always, if not always mentioned -- the threat of extinction.

"People have such faith that Arena will continue," said Fichandier at Arena's last big birthday, its 25th. "Where is it written that American society is capable of identifying Arena's contribution . . . or, even if it should identify it, of giving the theater tangible support so that it can enlarge upon its achievements in some kind of peace and surety?"

So at 30, Arena is trying, furiously, not to be taken for granted. That could be a tall order in a city of affluent, career-focused transients. But if Washington is ever to have anything like the cultural renaissance it has been advertising lately, it should begin by taking an accurate inventory of its assets. And where theater is concerned, Arena Stage, birthday or no birthday, heads the list.

The first miraculous thing about Arena is its persistence. For five years it survived in an old burlesque/blue-movie theater on Mt. Vernon Square, a space so ill-suited that actors had to leave the building (and cross an unfriendly alley) to get from a stage-left exit to a stage-right entrance, or vice versa.

"It was rough," says George Grizzard, who -- "made up like a witch" for one of those early Arena productions -- was so fearful of passing through the panhandlers, drunks and toughs in the alley that he used Pernell Roberts (the future Adam Cartwright of "Bonanza") as a bodygaurd.

The size of the house was another problem the company somehow overcame -- or, at any rate, outlasted. With 247 seats and a top ticket price of $2.50, a show could sell out and still lose money. When Arthur Miller's "The Crucible" did just that in 1954, Arena actually shut down for a season while it searched for a 500-seat alternative.

What it found was the ice-storage room of the old Heurich Brewery, where Arena reopened in 1956, in the full knowledge that the building would be demolished a few years hence (to accommodate an approach-way to the Woodrow Wilson Bridge). "It was all we could find," says Tom Fichandler, Arena's executive director.

Then Arena pulled off its most amazing coup. An institution founded with $15.000 in 1950 managed, a decade later, to raise more than $1 million and build a new facility on the Southwest Waterfront. It was the first professional American theater built, irrevocably, on the arena model. And it was "the first theater to be built in America on the basis of the collective experience of a company," says Fichandler.

In its choice of location, Arena was also ahead of its time -- perhaps unwisely so. Nineteen years after its move to Southwest, it is still waiting for Metro's long-promised Green Line, and is still the only significant cultural venture in its sterile quadrant of the city.

No lists of Arena's adversities would be complete without the sage of "The Great White Hope," the 19-scene, 62-character epic production in 1967, with which Arena won a measure of recognition on Broadway and in Hollywood, and lost a leading director (Sherin), a good deal of money and most of its actors.

"It was this play, nursed at Arena Stage, that became the big baby boy that won the Pulitzer Prize and (was sold) to the movies for something like a million dollars," Fichandler wrote at the time.

"When we asked (author Howard Sackler) for a small financial pat on the back, he consulted his morality for awhile and decided that since we had posed to him as a high priestess of the arts, and were now reversing roles, we had disqualified ourselves from his responsibility. . . . I require and now have learned to demand a worldly portion of what we help bring about."

Beyond -- and intimately related to -- the remarkable staying power of Arena is Zelda Fichandler herself. Raised in Washington, the daughter of a physicist, she majored in Russian at Cornell University and "my Russian professor told me I belonged in the theater."

She returned here as a graduate student in drama and, along with Edward Mangum, one of her teachers at George Washington University, co-founded Arena. Mangum disappeared to Hawaii the next year, leaving custody of Arena to Finchandler, with part-time help from her husband (an official of the 20th Century Fund), and, by then, the ongoing artistic collaboration of director Alan Schneider. She had never worked for another theater, and still hasn't. "And I love that," she says. "I know absolutely nothing, except by experience."

She learned to direct "when other directors failed to show up." But for all her early ignorance, she had a passionate and articulate view of the American theater she hoped to change. "What was essentially a collective and cumulative art form was represented in the United States by the hit-or-miss, make-a-pudding system of Broad-way production," she wrote later, recalling the attitude that led to Arena's founding. "What required by its nature continuity and groupness, not to mention a certain quietude of spirit and the fifth freedom -- the freedom to fail -- was taking place in an atmosphere of hysteria, crisis, fragmenmtation, one-shotedness, and mammon-mindedness within the 10 blocks of Broadway."

"Quality is considered a normal thing at the Arena," says Liviu Ciulei, the Romanian who is now artistic director of Minneapolis's Tyrone Guthrie Theater. "You need not struggle for it as you need to struggle for the normal at other places."

Ciulei's first work in English was staging George Buchner's "Leonce and Lena" for Arena in 1974. When the preview audiences didn't react as well as he had hoped, Zelda Fichandler sent him a reassuring note, which he still remembers. "All America isn't ready for you," she wrote. "We are.'"

"Once they've committed themselves to a production, they're absolutely behind it," says playwright Michael Weller, whose "Moonchildren" and "Loose Ends" had their U.S. premieres at Arena and wound up on Broadway. "They seem to have a commitment to new plays that's quite constant."

Another constant is Arena's refusal to solve its financial problems with a more commercially-oriented schedule. This season, for example, Arena will be doing works by Brecht, Sartre and the unknown Soviet playwright Nikolai Erdman, along with a repertory of new plays by equally unknown young Americans -- hardly an agenda from which anyone would guess that Arena's subscription has fallen (to about 15,000, at the moment, from 19,000 in '68-69).

Physically, too, Arena refuses to sweeten the package. Fichandler has described her theater as "all bone and sinew, no paint and powder." With the additon of the 500-seat Kreeger Theater, a conventional proscenium space that opened in 1970, Arena has the flexibility of a "ring" and a "room." But Fichandler makes no secret of her preference. "Some people do not like it, this ring," she has said. "But I love it with all my heart . . .It has never told me its secrets." The Fichanders' marriage broke up five years ago, but at Arena, "basically nothing has changed," says Tom Fichandler, who has been a paid, full-time employe since the move to Southwest. "We both wanted to continue in the theater. We felt responsible for it."

And, naturally, they want Arena to outlive them. "If something happened to me tommorrow, there's nobody who could step into my job," Tom Fichandler complains. "We're shorthanded generally and salaries are much too low."

Arena pays about 65 percent of its empenses from ticket sales and related revenues, and gets the remainder from foundations, corporations, individuals and the federal government. But Washington has few major corporations and no foundation as big as the seven or eight biggest in Philadelphia, according to Tom Fichandler. And, compounding matters, potential donors are constantly telling Arena that they give to the Kennedy Center, where, as one put it, "we get more bang for our buck."

So the process of elimination leads Arena to the government -- without apologies. "They're the city's major employer and we're servicing their employes," says Tom Fichandler. "Plus the fact that they're our state government. If we were in New York we would be getting money from the state arts council."

It was, therefore, a severe disappointment when the Interior Department decided last month not to designate Arena as a historic building -- which would have made the theater eligible for $200,000 in automatic, annual maintenance money (money that will now be split between the Corcoran Gallery and the Folger Shakespeare Library instead).

"But we're going to go back and try to convince them that they're wrong," says Zelda Fichandler.

Actors are the bottom line in this never-ceasing pursuit of funds. Arena is paying only five staff salaries of more than $20,000 a year (two of them to the Fichandlers), and "to really attract and hold a good comapny, we should be able to pay $50,000," says Tom Fichandler.

Otherwise, "how do you compete with 'Bonanza'?" asks Zelda Fichandler.