It was the end of May, the end of the season. On Friday night, the Phil would begin its final run of performances before moving for the summer from the Disney Hall (indoors, posh) to the Hollywood Bowl (outdoors, Sting plays there, you can eat a Snickers in your seat). For the finale of the orchestra’s 99th season, essentially the lead-in to this year’s centennial extravaganza, Dudamel was putting on “Das Paradies und die Peri,” Schumann’s gigantic concert oratorio: nearly two hours long, renowned singers in dramatic roles, a huge chorus, shattering climaxes, tunes for days. The text tells the story of a Peri, a kind of benevolent fallen angel, who can gain admission to heaven only by bringing the proper gift to the gates of paradise. She tries three times, in escalatingly romantic-allegorical ways, and it’s the third gift, the last tear of a sinner who repented on his deathbed, that causes the gates to open. The Peri enters heaven, to cloudbursts and hosannas.

Famous in Schumann’s lifetime, “Das Paradies,” composed in 1843, is seldom performed now; Dudamel came across it a few years ago and immediately felt he’d discovered a masterpiece. “I was like, my God,” he whispers, recalling the moment. “What is this? My God, how to deal for such a long time with that amount of beauty?”

The difficulty seemed great enough when he was studying the score on his own, but once he began working with the musicians, it became even more pronounced. On Tuesday of that week, when the full chorus came in to rehearse with the soloists, Dudamel realized that the production design had caused them to be seated too far back, all the way behind the stage, in seats normally reserved for audience members, from which hinterland they couldn’t see him properly and couldn’t hear the soloists. The chorus members had little LED lights that clipped onto their music folders so they could see their scores in the dark; from the podium, they looked like a sea of distant white pinpricks. Then on Wednesday, when the singers were joined by the full orchestra, it became clear that the location of the soloists’ elevated platform, which was positioned above and behind the instrumentalists, would make it hard for the Peri and others to be heard over the strings and winds. Now the singers were all out of sync, and the orchestra members were playing too loudly, because they weren’t listening to the singers at all.

Dudamel’s jean jacket was draped over his seat back. His sneakers, dangling above the floor, tapped on the stool’s chrome ring. He insisted on moving the chorus closer to the orchestra — moving them onstage, out of the audience seats, a change that demanded a serious reconfiguration of the planned arrangement of forces. Then he addressed the musicians. When Rousseau was a young man, he said, he loved to talk more than to listen. But as Rousseau grew older, he came to understand that listening was sometimes more important. “It is so important here, this concept,” he said. “It’s not about not playing — I’m not telling you not to play. But if you aren’t willing to do this kind of listening-playing, then you’ll never be able to do this. We’ll never have the space of the — the magic of that uniqueness. It’s not about where the singers are. They could be here in front, and I’m sure we would still have this problem. It’s about finding the way to be in the service of this” — he tapped the score — “and how it asks us to create that for the singers. So please.”

He raised the baton, a levare. On his downbeat the orchestra began to play. The winds came in first, with a fey, lilting figure, light but energetic, like the sound of water splashing in a fountain. Then a quartet began to sing. They had rehearsed this number a dozen times over the course of the week, but now something had changed. The violins began to double the singers, while the winds played extravagant swirls around them. The effect was astonishing. Where the chorus had sounded diluted, it was now vividly alive and present in the music. By the time Dudamel finished his adjustments, one of the singers had called out to him: “Thank you!”

The way Dudamel looks at it, he’s not a ruler; he’s more like an ally of the players. He is on hand to offer his thoughts, help them sound their best. Cooperation gets better results. Musicians, he thinks, are like everyone else. Music is supposed to feel good. Doesn’t everyone do their best when they feel good?