Andris Nelsons is in the middle of rehearsals for the CBSO’s concert-performance of Richard Strauss’ Der Rosenkavalier when we meet.

This autumn he will embark upon his final season as music director and principal conductor of the CBSO, simultaneously launching his inaugural season in the same capacity with the Boston Symphony Orchestra.

But his immediate thoughts are very much on his family rather than music.

Since taking up his position with the CBSO six years ago he has endured the long commute from his home in Latvia to work in Birmingham while his wife, soprano Kristine Opolais, travels across the globe performing. The couple have a two-and-a-half-year-old daughter, Adriana.

“Kristine is in Covent Garden singing Manon Lescaut, so I’m commuting to London,” he explains.

“Adriana comes to England on Sunday. I miss them both.

“Perhaps it will be better when we get to Boston. Kristine is involved at the Metropolitan Opera in New York every season. We’ll have to think when Adriana starts school, and that will be a decision to decide where exactly is home.”

Andris reveals his decision to move to Boston had not been an easy one to make.

“Leaving the CBSO was probably the most difficult decision so far in my professional life. I love the orchestra so much, and there is no reason, musical or human, to leave. Sometimes people leave because they think the relationship has got stuck, or whatever, but none of that is the case here at all, in fact I think the relationship is growing,” he explains.

“They have always loved their music directors, they have always supported and trusted them, and that makes it more difficult to leave. It’s an example for other orchestras. They love musically and humanly.”

Andris says he thinks the CBSO should take its time before deciding who will replace him when he leaves next year.

“They need to find the right person,” he says. “Sometimes it can be an immediate love and an immediate chemistry. I would suggest it’s a decision to take time over. They really need to know how to work together.”

And all the time I’m remembering how the CBSO instantly fell in love with Andris seven years ago and unanimously demanded his appointment as principal conductor (to which was added the accolade of musical director, something which, mysteriously, it took Simon Rattle and Sakari Oramo years to achieve).

“You could make a rushed decision, but then they might not be able to continue the great journey they have to make. I’m sad to be leaving, but we have still one-and-a-half years,” he adds.

“I don’t want to think about that, but we have so many concerts here in Birmingham, so many great things programme-wise.”

Can Andris point to any differences between his future work in Boston and his present work in Birmingham?

“It may be naive and very obvious, but musically it goes on beyond nationality and language, we understand without words. With any orchestra, whether as music director or as a guest, it’s based on musical and human chemistry.

“The audience is just as passionate about the orchestra, the same as here in Birmingham. The orchestra is part of a big family, which is part of the city and the country.

“Boston is almost like England, architecturally, and in so many other ways. I also think it’s one of the most European American cities. The sound of the orchestra is more European than in many other American orchestras.

“I’m looking forward to working with the orchestra, but for the audience, too, to be part of the family.

“This is not easy, thinking about this being the last season in Birmingham.”

What were Andris’ intentions when he arrived in Birmingham to become CBSO music director?

“It may sound stupid, but I didn’t come with the idea of wanting to change things. It is one of the great orchestras. My idea was to continue and just enjoy making music, to share my passion in music with them. I’m so honoured to be with such a great orchestra.

“In the search for someone after me there are so many conductors we haven’t seen, so it’s a great honour for anybody to take such an orchestra. When I came it was in such great shape and now I think it’s on top form. Technically and musically and flexibility-wise it’s doing so well.

“We’ll have our last concert next season in the Vienna Musikverein, Wagner’s Parsifal Act Three, so we’ll be able to show off the quality of the orchestra.”

But before that, the season kicks off with a complete Beethoven symphony cycle in Bonn, the composer’s birthplace.

“We’re very honoured with that accolade, and then we do it in Birmingham a week afterwards,” says Andris.

“What’s important to me is the flexibility and sensitivity of our music-making – which means I may have spoiled the orchestra’s rhythm because they come with me and my crazy ideas! The music is never mathematical, unless it’s Stravinsky or some other composers, it has to breathe, it’s like chamber music, you listen to each other.

“In an orchestra it’s not the conductor who dictates, it’s really a partnership. I adjust to them and they adjust to me.

“It’s the same when I go anywhere as a guest conductor. You should be yourself and they will follow you, they will believe in you. If you are a dictator, you should be a dictator.

“There are great conductors, mostly in the past, who were dictators and the results were great, and they were being themselves. And I think as a guest conductor if you have developed this kind of fantasy and flexibility of feeling as an ideal, if the orchestra was developed along the lines of mathematical perfectionism, it’s a combination of what the conductor can offer.

“All conductors are guest conductors and we should develop ourselves and we should not be the same every week. It can be a success but sometimes it isn’t and that’s absolutely normal.

“Sometimes even the great conductors don’t click with the great orchestras – Vienna Philharmonic, Concertgebouw, Berlin Philharmonic. But it’s the fantasy; you show with your hands that you have something to offer.

“If you like the conductor, if he challenges you in a musical way, some work more on technical details, some work on fantasy, there’s no one right or wrong direction, but if it’s interesting, this is where a professional conductor is mystical.

“You have a hundred people to follow you. You should not teach; whether it’s Vienna, or Liverpool, or Birmingham, you give the impulse, and they understand.”