On a fall afternoon, the St. Paul Chamber Orchestra rehearsed, as it most often does, without a conductor. No arms waved in the air to mark a tempo, an entrance, a note.

Rob Kapilow sat in the front row, a score in his lap, watching how they did it. During a tricky bit, when the violin soloist slowed, Kapilow inched up off his seat, hovering his body midair and craning his neck.

The strings slowed, too. The parts aligned.

Kapilow, grinning, turned around to the empty concert hall as if to say: “Did you see that?”

A composer and conductor, Kapilow is best known for breaking down — eruditely, enthusiastically — what makes a piece of music work. In his “What Makes It Great?” program, as well as his books, he homes in on a melody or a few measures, illustrating why, when a motif shows up in a new form, it tickles us. Why the reach of an interval moves us.

He explains symphonies and Sondheim without relying on technical music jargon. He does this without making us feel dumb.

This month, during nine performances with the St. Paul Chamber Orchestra, he’ll break down Beethoven’s iconic Seventh Symphony. But as the SPCO’s newest artistic partner, he also hopes to explain the chamber orchestra itself, especially the fact that it rehearses and performs without a conductor.

“I mean, a string quartet is one thing — to get four people together without somebody waving their arm,” Kapilow said during a September visit to St. Paul. “But to get 40 or 50 people? Or the hardest: 40 or 50, plus a soloist! I’m interested in watching how they do it. How do they communicate? How does it work? How do they figure it all out?”

Musicians often feel that music appreciation — which is how you might categorize Kapilow’s specialty — isn’t for them.

“It’s a little like: This is for the audience and not so much for us. We know all these things,” said SPCO artistic director Kyu-Young Kim. “And actually, with Rob, it’s never that way.”

Talking through a piece with Kapilow always leads to new discoveries, Kim said. “That’s very much why he has such a strong connection with these musicians. You can do a standard piece you think you know backward and forward, and then you realize you didn’t know this element.

“It changes how you think about it and changes how you play it, too.”

Kapilow will work with the SPCO for three years. For now, he’s focused on Beethoven. But the author and composer won’t confine himself to “What Makes It Great”-style programs.

During a post-rehearsal conversation last fall, during which he could scarcely sit still, Kapilow threw out a dozen possible projects and a few wild ideas. He talked about composing music about art, about history, about the Golden Gate Bridge. Here are excerpts, edited for length and clarity.

On listening:

“That was really fun to watch. There are so many little things going on unsaid. It’s funny. My first book was titled ‘All You Have to Do Is Listen,’ and in a way, this is a living example. ... No one says a word, no one writes anything. And no one’s actually moving their arm or conducting it at all. But somehow they all listen to each other. And believe me, in a society where listening is so rare, it’s really a wonderful example.

“When there’s a conductor leading, there’s people following. There are several places in that piece where the woodwinds don’t play for like 30 bars. Now, normally when a group of instruments doesn’t play for 30 bars, the conductor cues them. In a way, you’re removed from having to listen.

“Mostly, when you’re in an orchestra, you’d just get your part. The violinist sees one line — the violin part. The flutist sees the flute part. The cellist sees the cello part. But I didn’t realize that every player on that stage has the full score. In other words, they all get all the parts. That is massively different, you know, because when you’re just playing your part, it totally changes your picture. It would be like being an actor on stage knowing your lines, but nobody else’s.

“But here they all have the full score.”

On what’s possible:

“Originally, I was only supposed to come to do the ‘What Makes It Great’ program. And I said: ‘I don’t think that you will be getting the most out of me unless I get a sense of who’s here, what’s the community, what’s possible.’ So that’s why we added this entire week, which wasn’t on the original schedule whatsoever. So I’m really open to anything. I don’t care whether it’s psychiatrists or dairy farmers, whatever it is. And I’d love to have the orchestra see that they can relate to those people. Because then maybe it opens things up.

“Oftentimes we feel like as musicians that unless somebody likes what we do, we can’t connect with them. And there’s a kind of defensive posture ... we’re in our musical bubble. But I’ve learned I don’t want to be in any bubble.

“The biggest challenge or the biggest problem is when we say ‘outreach,’ what we really mean is ‘come to.’

“I do not believe that you can create change in any relationship — whether it be leading an orchestra or a community; a husband and a wife; a parent and a child — unless you are willing to change.

“Everyone says they believe in change and innovation. But most people, in my experience, would love to change just so long as they don’t have to do anything different, you know?”

On connection:

“I had a fantastic job in my 20s [as music director of the Yale Symphony Orchestra]. Then I got this offer to conduct on Broadway a Tony Award-winning musical.

“For three months, I tried foolishly to do both jobs at the same time. New Haven is about an hour and a half train ride to New York. I would conduct my Beethoven symphonies during the day, teach my course, go to Broadway, conduct the show and then take the 11:20 train home.

“It was a really eye-opening moment, because whatever you think about Broadway ... audiences got that music. They knew when to clap. They spoke that language.

“Then I would take the train back and do Beethoven’s symphonies. And the number of people who got that music in the same way was so infinitesimally small. It was deeply depressing.

“And so I said to myself, ‘I don’t really want to do this unless people are going to get it’ — because it seemed like the emperor’s new clothes, everyone pretending to get it, but no one really getting how great this music was. I didn’t want to pretend up there, waving my arms.

“I want it to be real. I wanted real connection.”

On composing:

“I was the first composer allowed to set a Dr. Seuss book to music. And the reason I did ‘Green Eggs and Ham’ [a children’s opera] was at the time I was reading the book to my kids. And I thought two things.

“One: If you could only set this to music, millions of kids would walk into a concert hall to see this and they would also get the power of music, ’cause it’s the only libretto every kid knows by heart. Everyone knows ‘I am Sam. Sam, I am.’ No one has ever heard it set to music before. And it’s really a parable about prejudice. I mean, that’s what the book is about — a child teaching an adult to try it. Try it. Really, the only thing wrong with the eggs is the color. I realized it would be an opportunity to talk to families about prejudice.

“The other reason: When my son was 7, one day he came home from school and said, ‘Daddy, Daddy. You can’t be a composer. You’re not dead.’

“And so I wanted kids to know that composers are actually alive.”