Across seven presidential administrations, you could hear it. Nixon played his piano to it. Barbara Bush quieted crowds to hear it better. Menachem Begin, Anwar Sadat, Queen Elizabeth II and Mikhail Gorbachev were among those who felt its deep resonance.

In a transient town like Washington, Michael Malovic's voice has been a constant. Now he, too, is moving on.

For 34 years, Sgt. Maj. Malovic has traveled with the U.S. Army Chorus, serenading presidents and potentates. At events ranging from joyful inaugurations to somber funerals, he has been a melodic witness to history.

Now Malovic is about to turn 55, the Army's mandatory retirement age for enlisted personnel. There is a certain irony to this, because, even as he prepares to end his Army career next month, his deep bass voice is fuller than ever. On Thursday, he appeared one last time with the chorus he regards as family after having been a member longer than anyone in its 43-year history.

"I'll miss serving my country, doing something I'm good at . . . but it's time for me to move on and give others a chance," said the Fairfax Station resident, who hopes to start a second career in opera.

An arm of the U.S. Army Band stationed at Fort Myer in Arlington, the Army Chorus entertains at White House and other government functions. Malovic can recite a long list of places and events at which he performed, among them: Lyndon Johnson's lying in state in the Capitol Rotunda in 1973; five presidential inaugurations; a dinner for the Apollo 11 astronauts in 1969; and a solo appearance at Camp David before President George Bush and first lady Barbara Bush and British Prime Minister John Major and his wife, Norma.

At the 1979 signing of the Camp David peace accord, with Israel's Begin and Egypt's Sadat looking on, Malovic was called upon to sing a solo in both Arabic and Hebrew--one of 30 occasions when he has been asked to serenade a guest of honor in his or her native tongue. Over the years, Malovic mastered how to memorize enough of a foreign song on short notice to carry the moment on such occasions.

More than once, Malovic has moved beyond singing and into the realm of diplomacy. It would be his voice, bringing life to an old Russian folk song or a Croatian wedding tune, that might turn a formal dinner into a congenial get-together.

"It's impossible to quantify the sense of loss" the chorus feels over Malovic's retirement, said Col. L. Bryan Shelburne Jr., the Army Band's commander. "He instantly understood the subtle implications of every action. He understood the implications in the choice of songs and in the choice of lyrics."

Colleagues describe Malovic's singing style as old-fashioned, his voice filled with emotion and dignified energy. That rich bass voice, like a fine aged wine, will be difficult to replace. "It's a low bass [with] an added Slavic quality. That's extremely hard to find," said Maj. John Clanton, Malovic's boss.

For all that, Malovic's Army singing career almost never got off the ground. In 1966, the young man from Ohio was taking an opera workshop when he was drafted. A friend from the workshop who was a tenor in the Army Chorus suggested that Malovic audition.

The chorus director expressed interest, but Malovic couldn't get a transfer. In the meantime, he graduated second in his helicopter maintenance class at Fort Eustis, Va., and was Vietnam-bound when he got his break--performing at the post commander's birthday party. There, he sang "Some Enchanted Evening," not coincidentally the general's favorite.

Enchanted it was. When the general learned the singing private was shipping out soon, Malovic said he exclaimed: "With your voice? Fixing helicopters? What's the Army coming to!"

In no time, Malovic was headed for Fort Myer and the Army Chorus.

Among his fondest memories of the past 34 years, Malovic recalls a White House performance at which an excited Nixon jumped up to the piano and played "On the Road to Mandalay," and Barbara Bush hushing a rowdy audience at a Christmas concert so that she could hear Malovic sing "Sweet Little Jesus Boy."

At his retirement ceremony Thursday at Fort Myer, Malovic stood at attention as his commander read letters of congratulation from Presidents Clinton, Bush and Ford, as well as Margaret Thatcher, another former British prime minister.

Then it was time for one last round with the chorus. Malovic took his spot in the second row. First they sang "Love Walked In," the first song Malovic rehearsed with the group in 1966; then "He Ain't Heavy, He's My Brother," which Malovic said summed up his feelings for the other chorus members; and finally, one last performance of "The Battle Hymn of the Republic."

When the last note sounded, the audience rose in applause, and Malovic bowed with everyone else. Then he slowly stepped down from the platform and left them behind.

CAPTION: Sgt. Maj. Michael Malovic hugs a friend after his retirement from the Army Chorus as his wife, Pinky, hugs another well-wisher.

CAPTION: Sgt. Maj. Malovic sings for the last time with the Army Chorus. He plans to pursue a second career in opera.