VIENNA -- U.S. presidents throw out the first ball at the World Series, and the arrival by carriage of England's monarch heralds the start of the Ascot races. Austria has the Salzburg Festival as its annual national rite, a tribute to Mozart and Richard Strauss opened every summer by its head of state.

This Thursday, President Kurt Waldheim will proclaim the start of the 70th annual festival, invoking the musical legacy that accords the small Alpine republic superpower status, at least in the realm of culture.

Since its founding in 1920, nearly every great 20th-century musician and singer has performed at Salzburg, likened by author Stefan Zweig to the "Olympic Games of Art." But this summer's event takes place in the midst of an unusual interregnum following the death of Herbert von Karajan a little more than a year ago.

The conductor had dominated the renowned festival for more than 30 years, so it is no surprise that change is in the offing. Under his imperious baton, Salzburg became a byword for prestige, luxury and sumptuous opera amid the picturesque baroque setting of Mozart's birthplace. Private jets and stretch limousines filled a town that came to be known as "Karajanopolis," carrying an international social and industrial elite unhesitatingly prepared to buy up top-price tickets at $250 apiece.

Bayreuth may be the oldest festival of its kind, but Salzburg gathers the most glitter. Film director John Schlesinger, who staged last year's opening performance of Verdi's "Un Ballo in Maschera," got it right when he said of the first-night audience, "They could barely put their hands together to applaud for the weight of the jewelry."

Karajan also helped turned Salzburg into an annual trade fair for the commercial world of classical music, an indispensable meeting place for agents, managers and recording company executives. The major classical labels, following the example of Deutsche Grammophon, with whom Karajan recorded exclusively, set up temporary summer headquarters in the city, blanketing every available shop window with advertisements for their latest releases.

Last year, the names and faces of of Jessye Norman and Riccardo Muti were writ large across Salzburg's taxicabs. This advertising blitz aims not so much to attract album-buyers as to lure big-name musicians with a potential marketing strategy for their image. "The artists, they walk around and count their pictures, how many times their posters are hanging in the windows," says a record company marketing director. "One tenor told off his company for not having enough of them pasted up. When Jessye Norman first appeared on the taxis, two artists called me up to say, 'Why don't I have my picture on a taxi?' "

Salzburg was not always this way. This year's festival will feature an exhibition and an opening night of readings from historic texts that recall the event's more modest origins two years after the collapse of the Austro-Hungarian monarchy. Founders Max Reinhardt, the pioneering theater director, and poet and playwright Hugo von Hofmannsthal envisioned the event as a counterbalance to the pressures of daily life, promoting European rejuvenation after the First World War tore the continent apart.

"An eminent undertaking on behalf of peace" was what Reinhardt had in mind. Hofmannsthal saw the festival as a way of reinforcing the fragile identity of the new Austrian republic that emerged from the once-great empire. "The Austrian idea is inseparably linked with Austrian culture," he wrote in one of his tracts outlining the festival's conception.

Betrayal of the original festival ideals was a frequent charge fired at the silver-haired Karajan. Even before his sudden death two weeks before the 1989 opening, many Austrians had grown weary of his grandiose showmanship. The musical quality remained largely unquestioned, with the Vienna Philharmonic contracted as the primary orchestra. But the relegation of innovative works to the sideline led critics to ask what made it different from other festivals that had sprung up around Europe or from what was offered in major metropolitan opera houses. They denounced the maestro for turning the five-week festival into a pompous extravaganza, a sclerotic personal fiefdom tied to his recording interests.

"Karajan came in and it was all money," says Gottfried von Einem, the Austrian composer who led an intense period of creative experimentation at the festival from 1947 until 1951. "It was the state that paid for it, but he considered it his own. ... The festival needs new blood because it has grown repetitive and does not provide enough impetus to the artistic world."

Responding to the tick of Karajan's biological clock, the Austrian government, which provides nearly a third of the festival's $35 million annual budget, called for a reform of the festival more than a year and half ago.

"There is a need for a renewal of spirit and putting some new ideas and new focuses into the festival," says Hans Landesmann, a member of the festival board who drafted a series of changes. "I think every festival or artistic institution has to look for a new focus, a new direction every 10 or 20 years. Nobody can sustain the excitement of a festival for such a long time."

Now the government has accepted Landesmann's plan to streamline festival management and bring in Gerard Mortier, director of the Theatre Royal de la Monnaie in Brussels, to shake up the artistic orientation, effective September 1991. Mortier attracted a series of experimental opera producers to the Monnaie and outraged a staid Belgian public by giving free reign to the Mark Morris dance group. "If it does not change itself, Salzburg is finished," Mortier declared before Karajan died. "I myself stopped going there along time ago, because it's deathly boring."

This year's festival programming, which includes repeat performances of "Un Ballo in Maschera" under the direction of Sir Georg Solti, Beethoven's "Fidelio," Mozart's "Don Giovanni," "Idomeneo" and "Cosi Fan Tutte," was arranged under Karajan's reign. The same is true of 1991, when the festival pitches in to help mark the bicentenary of Mozart's death. The changing of the guard will take effect with programming for 1992, when Mortier and Landesmann will form a triumvirate with Salzburg banker Heinrich Wiesmueller, who takes over from Karajan-appointee Albert Moser as festival president.

They will set the new tone with productions of Leos Janacek's "House of the Dead," the Czechoslovak composer's first opera ever performed at Salzburg, and Olivier Messiaens's opera "Saint Francois d'Assise." Several other premieres are in the works, with a heavy emphasis on the traditional Salzburg staples of Mozart and Richard Strauss, but much more contemporary music and theater are planned as well. New works will be commissioned especially for the festival.

The triumvirate pledges far more innovative stagings -- the buzzword "relevant" prevails. "The stagings have been very much in the spirit of the '50s and the '60s and stayed there," says Landesmann. Mortier also has begun talks with directors such as Peter Sellars, Luc Bondy, Patrice Chereau and several others, many of whom have never worked at the festival before.

To finance the rejuvenation, the festival is negotiating with corporate sponsors, another first for Salzburg. This is expected to bring in several million dollars in additional support. Prominent labels are also being encouraged to make live recordings of festival performances. A portion of sales proceeds from these would provide a new cash source, as has already been done at Bayreuth. The extra funding, which Landesmann envisages as coming on top of state backing at current levels, would enable a wider range of programming and allocation of discounted tickets for younger festival-goers unable to afford the high price of admission.

Under new management, the Olympic Games of Art appear certain to continue in an updated form. Karajan's death is but one in a series of departures by artistic giants from the Salzburg stage -- Reinhardt, Arturo Toscanini and Wilhelm Furtwaengler. "We lost a very great artist," says Landesmann of the current interregnum. "But the Salzburg Festival has lost great artists before, and things went on. ... At least for the near future, we do not want one single artist dominating the festival, because we want to attract the very best artists for the best possible productions."