But the music was the message, and this ebullient, effusive, emotional conductor's tragic, even strident interpretations of the two vast march movements from the Tchaikovsky and Shostakovich symphonies were too much for one listener, Tatyana Kudryatseva, a translator, who said the third movement of the Tchaikovsky was ''much too loud.'' She was in a minority: many people in the audience were so taken by it that they yelled ''Bravo!'' as it ended, spoiling the beginning of the last movement.

A Scherzo of a Reception

After his arrival on Sunday afternoon, the maestro was swept into a whirlwind of reunions, rehearsals and feasts. By Monday afternoon, exhausted in a delirium of joy, tears and bear hugs, even he was describing his reception as madness.

But it had its compensations. On Sunday, Mr. Rostropovich repossessed his old country dacha in Zhukovka and his apartment in the House of Composers in the city. ''It looks a lot smaller than it used to,'' said his wife, the soprano Galina Vishnevskaya. On Sunday evening the couple paid their respects to great Russian composers dead and alive and at a packed press conference in the government press center on Monday demanded that justice be done for Mr. Solzhenitsyn.

Because the Rostropoviches gave shelter and comfort to Mr. Solzhenitsyn for years while he turned out historical literary works that the authorities thought were as good as treason, the professional careers of Mr. Rostropovich and Miss Vishnevskaya were strangled. The couple was finally pressed into leaving the country on May 26, 1974, three months after Mr. Solzhenitsyn was arrested, expelled from the country and stripped of his citizenship. Mr. Rostropovich and Miss Vishnevskaya were deprived of their Soviet citizenship in March 1978 for ''acts harmful to the prestige of the U.S.S.R.''

To win back some of that prestige, the very different Soviet Government of today restored their citizenship last month.

'A Ridiculous Charge'

Mr. Solzhenitsyn remains in Cavendish, Vt., and says he will return to the Soviet Union only when all his books are freely available here. ''It is, of course, a ridiculous charge,'' Mr. Rostropovich said of the idea that his friend had committed treason in exposing the truth about years of Stalinist excesses in the Soviet Union. ''It should be removed as a matter of conscience.''