When the late George Szell took over the music directorship of the Cleveland Orchestra in 1946, he was determined to turn a respectable provincial ensemble into one of the finest in the world. And so he began his tenure by replacing the concertmaster, the first cellist, the first oboist, the first clarinetist and the principal horn. It was the musical equivalent of a president dismissing most of his Cabinet: In all, there were a flabbergasting 84 personnel changes in the orchestra during Szell's first five years. When one longtime player confided that he was thinking of buying a big house in Shaker Heights, a prestigious Cleveland suburb, the conductor looked at him scornfully. "I wouldn't," he snapped.

Leonard Slatkin, the National Symphony Orchestra's music director since 1996, has effected no such purge; indeed, it is hard to imagine that any present-day orchestra committee would stand for this sort of wholesale bloodletting. And yet the NSO is now a vastly different group than it was when he took the helm, and there can be no doubt that his decisions have been directly responsible for the orchestra's current level of versatility and virtuosity.

Since 1994, when Slatkin became music director-designate, he has named 31 NSO players -- almost one-third of the orchestra's 100 members -- to their current positions. (Of these, six musicians were already in the orchestra and received promotions.) Slatkin's appointments include principal players for all five string sections (first and second violins, viola, cello and bass), three assistant principal string players, principal bassoon, horn and timpani.

"The personality of an orchestra reflects the tastes of the music director," Slatkin said recently. "Sometimes you can encourage existing members to alter their approach to suit your purposes, but for the most part, you inherit the sound of the previous conductor, assuming he had one. Therefore, it is the appointment of new personnel that determines the overall sonic characteristics of the orchestra.

"Many of the musicians who played in the NSO before I arrived had a brighter sound than the one I prefer. As some of those players retired or left -- nobody has been dismissed -- I had the opportunity to alter the overall sound. Most of the winds and principal strings that have entered the orchestra have the kind of sonority that I am seeking. They also seem to fit in well with the players that are already here."

Slatkin acknowledged that he has hired more musicians than he had anticipated by this point. "But I also think that the quality of new members is very high. The standards that we have set for the auditions are quite rigorous."

How does a musician qualify for admission into the NSO? The process begins with an advertisement the orchestra places in International Musician, the house newspaper for the American Federation of Musicians. "Anyone from anywhere can apply," Slatkin said. "They send in tapes that are heard by an audition committee. That boils down the number to 50 or a hundred people, who pay for their own transportation and are heard live. Then we pare down the group to about 15 to 20 people who will play the semifinals, and that in turn results in about eight to 10 players making it into the finals.

"At that point I get into the proceedings," Slatkin continued. "Until this level, all auditions have been 'blind' -- behind a screen -- so we do not know anything about the musicians. For the finals, the screen comes down.

"Personally, I don't care for the screens at all. A large part of what we do is visual, and the audience sees as well as hears us. But the screens come down in the finals because it is assumed that the people who get that far have done so totally on merit. The screen also changes the sound somewhat, and we want to hear the player in an acoustic that is as close as possible to how he or she might actually sound in the orchestra."

Removal of the screen also makes it easier to see the response to specific changes ("slower," "faster," "more lyrically" and so on) that might be requested by the music director and therefore more closely approximates the rehearsal experience.

Each finalist plays for Slatkin and the audition committee for about 20 minutes -- starting with excerpts from concertos and then moving on to some fragments from the symphonic repertory. "Then we vote by secret ballot. If the results are overwhelmingly in favor of one player, that person will be offered the position. If it is close, we might ask those who received a majority of the votes to play again. And then, if it is still close, I can decide who, if anyone, will get the job. It has happened that we did not feel anyone met the requirements, and so no position was offered.

"In that case, we start all over again."

When the appointment is an especially important one, a musician may be invited to "try out" with the orchestra before being offered the job. "We might ask the player to sit in with the section he or she is trying to join -- or even at rehearsal with the entire orchestra," Slatkin said. When the NSO was searching for a concertmaster, four different violinists played for a full week each with the orchestra before Nurit Bar-Josef was appointed in 2001.

"We also look at the skills the new players bring outside their playing abilities -- teaching, communications and outreach," Slatkin said. "This is very important in light of the many activities the NSO does each season."

Slatkin notes that he has never gone against a majority of the orchestra audition committee. "I feel as if all of us are on the same track regarding new players," he said.

Those players can come from anywhere. Principal second violinist Marissa Regni hails from the St. Louis Symphony Orchestra, where she had worked with Slatkin during his tenure as music director. John J. Tafoya, the principal timpanist, had held previous top positions with the Florida Philharmonic Orchestra, the American Wind Symphony and the Colorado Philharmonic Orchestra. Sue Heineman, the principal bassoonist, repatriated to the United States from halfway around the world, where she had been associate principal bassoon in the New Zealand Symphony Orchestra. David Hardy, the principal cellist, was promoted from within the orchestra, as was principal violist Daniel Foster. (Indeed, the Foster family has a long history with the orchestra: Daniel's father, William, has been playing in the NSO for almost 35 years and now serves as assistant principal viola.)

The duties of the players vary considerably: A violinist will be busy throughout the show, while a harpist may wait for half an hour to strum a few chords, and then sit back and wait some more. Nevertheless, each musician in the orchestra has a part to play, and a certain familial unity is essential. Things have changed in the musical world since George Szell terrified the Cleveland Orchestra into greatness. Still, gently but unmistakably, Slatkin is creating his NSO.

Since '94, Leonard Slatkin has named 31 of the National Symphony Orches-

tra's players to their current positions.Concertmaster Nurit Bar-Josef was one of four candidates who each played for a full week with the orchestra in 2001.Though the NSO has made many hires from outside when openings have occurred, principal cellist David Hardy, front, was promoted from within the orchestra.