The 26th annual NSO Ball last night at the Sheraton Park Hotel featured a full complement of players -- 1,200 strong, a record -- and built to a crescendo that was sustained throughout the evening.

Contrapuntal figures in white tie and glitzy satin and chiffon, doing their duty at $150 per person, found themselves in concert as they elbowed to the cocktails. Later the lights had to be dimmed at least five times before the prompters could get them to proceed to the next movement: Dinner and dancing.

"I perdict it will be the most elegant of any symphony ball," said board member David Lloyd Kreeger at the start of the evening, "and that's shooting very high indeed."

Elegant it was. Despite the warehouse ambience of the mid-renovation Sheraton Park (the ladies' room is through the kitchen . . . to the left . . . then right), the crowd took it in stride.

"I see they have the same music as last year," said one women, not at all sadly, as she entered to the strains of the old Piaf chestnut "Milford," jazzed up by the Gene Donati orchestra.

Elegance is immutable.

In other cities, the traditional underwriters of culture are local corporations. True to form, many of the supporters at last night's ball were representing this town's largest industry: sgovernment. They were there with their foreign counterparts and their own support systems.

National Endowment for the Arts Chairman Livingston Biddle was a natural, of course, as was Sen. Larry Pressler (R-S.D.), an inveterate party-goer. In the foreign contingent were OAS Scretary General Alejandro Orfila, Japanese Ambassador Fumihiko Togo, Saudi, Arabian Ambassador Faisal Alhegelan, Irish Ambassador Sean Donlon and a multitude from the German delegation, which co-sponsored this year's ball.

National Security Adviser Zbigniew Brzezinski stated he had "nothing to say about Iran tonight . . . and preferably every other night."

But Elliot Richardson, special delegate to the Law of the Sea negotiations, offered some reserved speculation: "For Khomeini, solidarity is important," he said, and the uprising in Tabriz "may encourage him and his followers to focus more on the United States as the outside enemy to bring the country together."

More taciturn was senior presidental advisor Hedley Donovan, who complained that "the president and I have an agreement that I don't talk about what we discuss.

"I love speculating and talking about these things myself," he confessed. "It's hard for me to be in this position."

Acting Secretary of Commerce Luther Hodges Jr. was more interested in speculating about the balance of trade in a country in which "65 percent of the working population is involved in service"; that, he asserted, was one of the basic problems of our oil-dependent nation.

As for his support of the symphony, definitely a service organization and a cultural one at that, he had an explanation. "Music is the kind of thing that releases you so your mind is free to be productive."