Andrei Voznesensky came to town last night and read his poem for a standing-room audience in the Smith-sonian Castle. It was a spur-of-the-moment event, and all the better for the resulting air of spontaneity. The Russian poet, who is making his fifth visit to the United States, told the Smithsonian's Kennan, Institute last Friday that he would like to give a reading, and "we decided on Monday that we would sponsor it," said Fred Starr, secretary of the Institute. Out of nowwhere, an audience of more than 150 materialized within two days-a capacity crowd for the Castle's rather small auditorium-and in the two hours of the bilingual reading, with American poet William Meredith giving translations, the audience got a show to remember.

Voznesensky's stage presence is something like that of a French singer -perhaps a young, good-looking Charles Aznavour. Lacking musicians, his voice provides its own music, ranging widely in pitch, tone and dynamics. His right hand moves constantly-up and down like a conductor's or flinging out sideways in an expressive gesture. Usually the plan is opened, but sometimes, in moments of special intensity, the first clenches to drive home a message: for example, to those who make it hard to be a poet in the Soviet Union: "Eat pie with your fingers/no dip your chicken in the salt/but I ask one thing of you: /Keep your hands off music."

A whole world walked into the room with the medium-sized, muscular frame of Vosnesensky. He took his listeners to the funeral of Gogol, who was buried alive in a coma and when they dug him up later and found that his body had changed position: "Gogol, writhing, lies on his side. His twisted toenail has torn the lining in his boot." And without any great effort, this horrible scene became the symbol of the writer buried in a society that doesn't pay attention to him.

"Try to understand what I'm about. /No, they are going away two by two!"

He shifted the scene to a phone booth where someone is making anonymous calls to his number and not saying a word. "Allo, allo, allo," said his voice in anguish. "Otzoi, otzoi, otzoi," Meredith supplied the elegant translation by Richard Wilbur: "Hello. Hello there. /Dial tone. Dial tone. Dial tone."

Most of the poems he read were from his latest book, "Nostalgia for the Present," and he explained that the Russian "Nastoyashimu" means not only "the present" but the "genuine-reality-altogether in one word." That explained partly why his poems are so hard to translate, but only partly: "Nostalgia Po Nastoyashimu" has a kind of resonance and internal rhyme that is flattened out of existence in "Nostalgia for the Present." Many of his poems play with sound this way.

In one poem, for example, he has a biting comment on cultural exchange: "We send them our best ballerinas/and get Pepsi-Cola in return." This loses a lot of its sparkle in English because our word for "ballerina," unlike the Russian's, doesn't sound at all like "Pepsi-Cola."

Some of the flavor of this word-play came through in the translation of his latest poem-about the recent event in Guyana-in the expression "cynical cyanide," leading up to his conclusion that it is "not for us criminals to judge."

This special sound reaches a high point in the early poem, "I Am Goya," in which he sees the horrors of World War II through the eyes of the Spanish artist. The Russian title is "Ya Goya," and the whole poem has the syllables "Ya" and "Go" popping out all over the place. Hearing him recite it is like music; seeing him is like a small drama with one actor. His books, in comparison, are like the program notes to an opera.

The tone of his poems includes unabashed sentiment, as in his tribute to Robert Lowell, translator and freind, standing in the graveyard before the stone on which, "the name that you once had rests like discarded clothes." At another extreme, as in his tribute to "the Russian intelligentsia," there is a thinly vieled irony that almost echoes poems which are regularly published in dead earnest, and even set to music, in the Soviet Union: "How fine it is to serve it, /and saluting it, to aver: /'At your orders, intelligentsia! Long may you live Yes, sir/" There is, for Americans who look at the Russian text, a small irony unavailable to Russians in the poet's unconscious reference here to a current American phenomenon. The word which is translated "At your orders" and later "Yes, sir" reads "Est" in Russian. CAPTION: Picture, Andrei Voznesensky, by Gerald Martineau