"Ladies and gentlemen," the voice of Steven C. Rockefeller Jr. echoed through Avery Fisher Hall this afternoon. "Maestro Rostropovich has promised us an encore during the awards ceremony."

So far, so good. But Rockefeller continued with a remark that established new standards for inaccuracy: "Thank you for remaining seated."

Because at the moment, nobody was seated in the Lincoln Center concert hall. Rockefeller's announcement came in the third minute of one of four standing ovations for Mstislav Rostropovich, music director of the National Symphony Orchestra and recipient of the fourth Albert Schweitzer Award for "a life's work dedicated to music and devoted to humanity."

Rostropovich's first two ovations were shared with the NSO, which he had brought along to New York. The last two were for him alone. One came when he was handed the Schweitzer Award by Rhena Schweitzer Miller, daughter of the Nobel Peace Prize-winning musician, doctor and humanitarian, with thanks for his "gift of a unique musical offering." The other followed his promised encore, a Bach sarabande for unaccompanied cello, which Rostropovich offered "instead of a long speech, especially with my not-enough-improved English."

Clearly moved by the award and the repeatedly invoked name of the great Bach scholar, Rostropovich, 58, told the audience that he was offering the music "as a prayer," and that was how it sounded.

After the solo, Rostropovich's final standing ovation was preceded by one of those special moments of silence that happen much less often than standing ovations. The audience seemed to hold its breath for nearly half a minute, absorbing a musical experience it had just shared, before breaking the silence and the spell and leaping to its feet.

"I, today, especially, happiest man in world, maybe," he told the audience. "I feel that you give to me back the love that I give to you through the music."

The cello solo, brief but eloquent, was possibly the finest solo performance this critic has ever heard from Rostropovich. It showed, in its short span, a new depth and ease of expression in music with which Rostropovich has been wrestling for several years, preparing for his first recording of the Bach solo cello repertoire. He may have found an ideal approach -- at least one that was especially apt for this musician on this occasion.

This year marks the 10th anniversary of the Albert Schweitzer Music Award, given to musicians who have also been notable humanitarians. During the ceremony, Rostropovich was cited for "his charity toward fellow artists and fellow Russian exiles." Rostropovich and his wife Galina Vishnevskaya sheltered Soviet dissident writer Alexander Solzhenitsyn in their home outside Moscow for several years after the writer had been made a "nonperson" by the Soviet authorities, unable to find work or a place to live.

Rostropovich and Vishnevskaya were granted exit visas for exile in the West in 1974 and were stripped of their Soviet citizenship in 1978. They travel on Swiss passports.

The Schweitzer award is given by the Creo Society, a nonprofit sponsor of special events that benefit creativity in the arts. Rostropovich is the first non-American to receive the award, which was given to violinist Isaac Stern in 1975, to choreographer Katherine Dunham in 1979 and to pianist Van Cliburn in 1983. Net proceeds of the benefit concert and of a reception and dinner dance at the Plaza Hotel are being given to the Mannes College of Music in New York.

Before Rostropovich's brief speech, the lineup of introductions at the awards ceremony had included an impressive array of names. One name who sent regrets ("Nancy and I wish we could be there") was Ronald Reagan, who called Rostropovich "one of the brightest ornaments of the Washington scene" and "a national treasure." Armand Hammer, cochairman of the event, was unable to attend, but his regrets were given by Gordon P. Getty (also a cochairman, and a composer among his other distinctions).

For the gala dinner dance, the theme was "A Winter Palace Revisited," and the Plaza's Grand Ballroom was decorated in the style of a Russian winter palace of the Czarist era. The decor included living statues -- mimes with their faces brightly painted who stood motionless holding a special award given to Henri and Eugenia Doll, New York philanthropists who have contributed extensively to the arts and also have opened their home to many Soviet emigre' artists, including Rostropovich and his wife. Rostropovich presented the award -- like his own, an engraved crystal obelisk about a foot high -- and said it was "a special honor" to give recognition to this couple whose "door is always open."

After the ceremony, evidently relieved that the official part of the evening was ended, Rostropovich took a bunch of grapes from a table and posed for pictures with the living statues, kneeling and holding the grapes behind his ear.

In the concert preceding the award ceremony, Rostropovich conducted the New York premiere of Aulis Sallinen's vigorous, colorful Fifth Symphony, "Washington Mosaic." He was the soloist in Haydn's Cello Concerto in C, playing with a reduced orchestra. This performance, which provoked his first standing ovation, had the special sense of intimate dialogue that one usually finds only in chamber music, particularly in the slow movement.

For the final selection, Shostakovich's Fifth Symphony was substituted for Beethoven's Third. The audience broke out into applause when the substitution was announced. Rostropovich and the NSO have become internationally known as interpreters of this music, and today's performance showed why.

At last night's party, among the New York socialites and NSO board members and, was Maxim Shostakovich, stopping over in New York for the day between Hartford, Conn., where he had just conducted Beethoven's Symphony No. 3 ("Eroica"), and Washington, where he begins rehearsals Monday for the Washington Opera's producion of "Eugene Onegin." "I came expecting to hear Rostropovich's 'Eroica,' which I thought would be good for me," he said. "Instead, I heard him conduct my father's Fifth Symphony, and that was not bad for me, either."