Why would one of the world's greatest trumpeters want to quit playing to become a conductor?

Gerard Schwarz, 31, crossed his stocky arms and said: "I arrived at the goal of my life, that is, to be the first trumpet in the New York Philharmonic, and I found out I wanted more.

"A conductor, of course, deals with great music much more than he would if he were a trumpeter. The trumpet doesn't have a large repertoire. Much of the world's greatest music doesn't involve the trumpet." Since 1977, when Schwarz left the Philharmonic, he has steadily carved out a growing conducing career for himself. He's now music director of both the "Y" Chamber Symphony in New York and the Los Angeles Chamber Orchestra.

In exchanging his trumpet for a conductor's baton, Schwarz as Pinkas Zukerman and Daniel Barenboim who've turned to conducting.

However, it's not a new trend. Stokowski was an organist and Koussevitzky a double bassist. Mahler was once better known as a conductor than a composer. Liszt excelled as a conductor and pianist. And Gunther Schuller played French horn before becoming a composer and conductor.

Schwarz" conducting career started quietly. From 1965 to 1979, he conducted the orchestra for the Erick Hawkins Dance Company (his wife, Lillo Way, was a member of the company; she now co-directs the Greenhouse Dance Ensemble and teaches at Hunter College).

His first important conducting assignment came by accident at Aspen in 1973. Brazilian conductor Eleazar de Carvalho became ill and couldn't conduct Elliott Carter's Concerto for Piano and Orchestra. So Schwarz was drafted because of his previous experience.

Sitting in the studios of radio station WQXR after being interviewed about the Waterloo Music Festival, which he directs, Schwarz shifts his thick 5-feet-8, 180-pound frame.

"Sam Lipman [the pianist performing the work] gave me the score," he recalls. "He told me how to beat the rhythm and asked me to come by his house the next morning.

"That next day his wife stood up and conducted while he played piano. She got all the beats correct. It's a complex piece metrically. I said, "She should conduct." But I learned it."

Carter was so impressed with Schwarz" performance that he asked him to conduct his Double Concerto for Harpsichord and Piano a year later.

The Aspen experience, says Schwarz, gave him the desire to try full-time conducting. For the last two years he was in Philharmonic, he was spending half his time playing trumpet and the other half conducting.

Some of his fellow trumpeters have mixed feelings about Schwarz" decision to abandon the trumpet.

Roger Voisin, retired principal trumpeter of the Boston Symphony, says, "He's absolutely one of the best (trumpeters) in the world. I hate to lose him as a trumpeter.But I know his career in conducting is skyrocketing."

Armando Ghitalla, principal trumpeter of the Boston Symphony, says, "He's an extraordinary trumpet player. But he's an aggressive, ambitious man and wants to do more. I can sort of feel his frustration."

But William Vacchiano, Schwarz" first trumpet teacher and retired principal trumpeter of the New York Philharmonic, cheers his former student. "Five years ago when I saw him conduct at Aspen, I told him he should become a conductor. The Carter piece was very difficult and he handled it. If he conducts, it'll be a gain for him and the music world. There're very few good conductors."

Schwarz emphasizes that he hasn't stopped playing trumpet completely. He'll pick up his horn in August at the White Mountains Music Festival in New Hampshire for the premiere of a trumpet concerto he commissioned Schuller to write.

By commissioning new works, Schwarz has made it his business to expand the literature of the trumpet.

"The trumpet in particular needs a large repertoire that it doesn't have," he says. "So as a soloist I was very concerned with getting new works written for the instrument."

No 20th-century composer has written a significant work for the trumpet, says Schwarz. And in the entire history of European music, he adds, there probably exist only about 10 important trumpet works - several Baroque pieces by Telemann, Torelli and Vivaldi, Bach's Second Brandenburg Concerto, and from the classical era the Haydn and Hummel trumpet concertos. He adds two from the Romantic era - concertos by Ariutunian and Boehm.

"The problem with 20th-century composers," he explains, "in writing trumpet concertos is the problem of performance. One can look at any orchestral schedule, whether it was 1900 or 1980, and you'll see there are 25 pianists playing solos that season, four or five violinists and maybe one cellist. Those are the solo instruments of our era. So is a composer writes a trumpet concerto, it's kind of wasted."

The public says Schwarz, is not educated toward wanting trumpet concertos; and when audiences hear them, they want the familiar works by Haydn or Hummel.

However, trumpeter Maurice Andre has opened the way for audiences to accept the trumpet as a solo instrument, similar to the way Jean-Pierre Rampal has opened new avenues for the flute.

"Maurice has done a lot just by doing transcriptions," he says. "For years I refused to do that. If you wanted to have a Tartini violin concerto, you should have a violinist play it. I don't mind it anymore. As I get older, I get more flexible."

The characteristic separating Schwarz from almost all trumpeters, including Andre, is his staggering versatility. He's an conversant with the stately, elegant contours of Baroque works by Telemann and Torelli as he is with the high, swooping glissandos and guttural sounds of Dlugoszewski's "Space Is a Diamond." And in each case his rich tone and striking musiciality burst through.

Schwarz also has unearthed many early 20th-century cornet solos by bandsmen like Herbert L. Clark, Walter Smith and Frank Simon - the graceful, lyrical solos that many high schoolers play in band competitions.

"When I was growing up, we all looked down on those solos," recalls Schwarz."We'd say, "You play Herbert L. Clark, we play Haydn." We'd do our Arban exercises and play the major concertos.

"But there came a time when I started playing through those pieces. They were very difficult. I couldn't really play them. So I had to play a few of them and I loved it. The music made me happy. It made me smile."

Later, he made a record of some of these solos - "Variations on "The Carnival of Venice," " "The Bride of the Waves," "Willow Echoes." The album "Cornet Favorites" won the Stereo Review trecord of the Year Award in 1974.

Schwarz started playing trumpet at age 8, four years after he started piano lessons. Hs Viennese parents - his father a surgeon and mother a psychiatrist - were amateur pianists and took their three children to operas and concerts.

After seeing a performance of "Aida" at age 6 1/2 and hearing the opera's triumphal march, Schwarz decided trumpet was his instrument. But he had to wait until he was 8 to take lessons in the Weehawken, N.J., SCHOOLS.

He had no trouble playing trumpet because he already played piano. At age 11, he went to the elite Interlochen Music Camp in Michigan. As a high school freshman, he was first trumpet in the all-New York City orchestra.

Next came Juilliard and positions with the American Symphony Orchestra and the American Brass Quintet before the New York Philharmonic.

In between he researched trumpet literature for articles, scores and recordings (Ghitalla says what Schwarz has recorded "is like a library. It's there for everyone to go to"). And he still talks avidly of how trumpet playing has changed in the last generation.

"Starting with Vacchiano, it took on more vibrato and a much more lyrical way of playing," he says. "The aim was to play with a slightly darker sound. Harry Glantz and Roger Voisin played brighter than we play nowadays.

"Now we play with incredible accuracy. You rarely hear a mistake from a first trumpet player in an orchestra. And pieces a generation ago that were considered playable by only a handful of people are now pieces that everyone plays."

It's changed in other ways, too.

"Eliott Carter's Symphony for Three Orchestras' starts with a trumpet cadenza that was written for me," he explains. "It sounds like a bird flying through the sky. That's a direction in which the instrument is going - a very vocal direction.

"So much of what we're doing now is based on what we've learned from the jazz players in terms of half-valve sounds, flutter tongue sounds, the use of mutes, the different possibility of range that we never even thought of until Cat Anderson and Maynard Ferguson came along.

"First, we influenced them and then they influenced us. No it's gotten to the point where most good legitimate symphonic players can play in a jazz style well, and most jazz players can play in a very legitimate style well.

"I just did a record date the other day with Lew Soloff for Pink Floyd, an English rock group. I loved it."

Who are some of the jazz trumpeters he listens to?

"I haven't listened to jazz trumpeters much lately," he answers. "But I used to be a great fan of Clifford Brown. He was my favorite by far. His sound really got to me. I thought it was one of the most gorgeous sounds I ever heard. It was a fat, rich, beautiful sound. And the musical ideas seemed so strong."

He also says he likes Art Farmer, Maynard Ferguson, Miles Davis, Conte Candoli, Dizzy Gillespie, Jon Faddis.

"I know Jon," he says. "He used to imitate my solos. He'd pick up his B-flat trumpet and play all my piccolo trumpet solos, right off the record. Just knock them out. It was incredible.

"All those guys have been a great influence on me because they play the trumpet in a very vocal way - in a way I believe the instrument should be played, not when you're playing fanfares in orchestra but as a soloist."

Conducting will mean an even more hectic pace for Schwarz, who says he already rushes from one project to another.

After finishing the Waterloo Musical Festival, he'll spend August at the White Mountain Music Festival. In October he will be guest conductor for the San Francisco Symphony (recently auditioned for the orchestra the trumpeter who defected from the Leningrad Philharmonic while on tour of Japan).

Next comes the season with the "Y" Chamber Symphony and the Los Angeles Chamger Orchestra. He's also music director of the Montclair College Chamber Orchestra and conductor of the Eliot Feld Ballet. And he teaches at Montclair College and Juilliard.

But conducting has become his main interest.

Is he aiming for a position with a symphony orchestra?

"It's hard to say what I'm aiming for," he says. "I'm aiming to stay involved with great musicians and great orchestras for the rest of my life, I hope." CAPTION: Picture, Schwarz: "As I get older, I get more flexible." By Dan Goodrich for The Washington Post