Wanted: conductor comfortable with repertoire from Bach to Bernstein. Inspiring presence, quick study, good negotiator. Appreciation of ballet a plus.

New York City Ballet will lose its much-praised music director, Andrea Quinn, when its spring season ends on June 25. For the last year and a half, NYCB has conducted a search for her replacement, bringing in several guest conductors to show their chops with the company’s challenging repertoire. According to administrators, dancers, and musicians, the process has been exciting- but the job requirements are so specific that NYCB has taken its time. Even after the extended search, the company is continuing to make its decision. A new director could be appointed any day during the upstate season in Saratoga Springs, but the search could also last until the fall.

The process has taken this long because of two major hurdles: first, finding someone who can master a wide repertoire and inspire the orchestra; second, finding someone who is flexible and willing to compromise to meet the dancers’ needs. Huge egos need not apply.

The long search has had an impact on the company’s dancers and, above all, its orchestra. A soloist, Jason Fowler, said he’s found it exciting, although there have been a few surprises in performance. “Some of the tempos have been really fast,” he said. When a guest conductor “is nervous, their adrenaline gets pumping. We keep up as well as we can.”

The orchestra members have found the process more trying, as the NYCB general manager, Kenneth Tabachnick, acknowledged. “If you imagine that you have a different person leading every piece that you’re doing every night – and some of them you may not have seen many times before – it can be a bit unnerving,” he said.

The musicians have a running joke about the stream of candidates coming through – some of whom are greener than others.”One of the musicians calls it ‘The New York City Ballet School of Conducting,'” said the NYCB orchestra pianist, Cameron Grant. “We’re teaching them the business.”

Both Mr. Grant and Ms. Quinn said the most important thing the company should look for in a new music director is the ability to inspire the musicians. “The conductor should be the smartest person in the pit,” Mr. Grant said. “Someone whose personality allows us to play our best.”

“For the orchestra, it’s a tough job,” Ms. Quinn said. “They’re in the pit every night, and it’s important that they feel inspired. They’re looking for someone who can do it for them.”

The music director of a ballet company like NYCB has a broad range of responsibilities, some of them administrative, but the top duty is maintaining standards. “The music director is responsible for the quality of the orchestra,” Mr.Tabachnick said.

The quality and range of the repertoire were what originally drew Ms. Quinn from London’s Royal Ballet, where she had been music director for three years, to NYCB. Unlike the Royal, NYCB dances only a few three-act story ballets. “It’s a very symphonic repertoire: We don’t do the [Leon] Minkus, the [Ricardo] Drigo, the Adolph Adam,” Ms. Quinn said, referring to the composers of ballets including “Don Quixote” and “Giselle.” “These are very fine ballets, but the music is not as great as the music of Stravinsky, Ravel,Tchaikovsky.”

NYCB performs works by these and many other composers, as well as a significant number of newly commissioned works. Each season involves a rotating repertory of as many as 50 oneact ballets. “It’s an incredible job, because the repertoire is so huge,” the music director of American Ballet Theatre, Ormsby Wilkins, said. “Anyone coming into that job has to be a quick learner.”

Each candidate for the job, on his first visit, was given two or three pieces to conduct, each of which tested different strengths. “One piece might show difficult rhythmic issues,” Mr. Tabachnick said. “Some might show how they do with lyrical, romantic pieces.” And, because NYCB’s conductors often have to conduct new work, Mr. Tabachnick asked the candidates for lists of the repertoire they’ve conducted, so he knew whether he was giving them pieces with which they were already familiar.

At a ballet company, of course, the music isn’t the whole show. The dance comes first.”It has to be somebody who understands the music but can also look beyond it,” Mr. Tabachnick said. “Adjustments have to be made to fit the dance. Sometimes it’s tempo, or sometimes a certain instrument needs to be brought out more, because the dancers need to hear it, and they can’t. It means the conductor must be able to lift their eyes from the music and watch the stage at the same time.”

But while Ms. Quinn often made adjustments for dancers, she is grateful that this company has a tradition of respecting a composer’s intents. “There are traditional ballet companies where the music is very much the servant of the dance,” she said. “You might alter the tempo several times during a variation to accommodate a dancer. That’s done far less here. It would be frowned upon to distort the music that way.”

In recent seasons, the company has hosted a long list of guest conductors, including some who were not candidates for the job. The field has been narrowed to “four or five people whom we are really interested in,” Mr.Tabachnick said, though he declined to name the finalists. A likely contender is music director of Orchestre de Pau Pays de Bearn, Faycal Karoui, who is scheduled to conduct at the company’s Saratoga season. The Frenchman won kudos from Mr. Grant, the pianist, who said: “Faycal is flashy, clearly a good musician, and exciting on the podium. I think a lot of people really responded well to him.”

Mr. Grant also said he enjoyed working with Paul Hoskins, music director of Rambert Dance Company in Britain, and Benjamin Pope, a guest conductor with the English National Ballet and other companies. In fairness to its peers, NYCB wants to avoid poaching a music director from another ballet company, Mr. Tabachnick said. “We have been very careful to not speak with people who are permanently engaged,” he said. “We’ve been very judicious in that way.”

Mr. Tabachnick said they would like to name a new music director by the winter season in November, but they aren’t going to rush.

“Peter and I are clear that we would rather have the right person, and if that means that we don’t have someone for a period of time, that’s fine,” Mr. Tabachnick said. “It’s a marriage. And first dates are always fun, but it’s that second or third or fourth date that makes you wonder sometimes.”