“Damien told me a couple of years before we even got to the piano that this score had to sound completely different than anything we’ve ever done,” Hurwitz, a two-time Oscar winner for “La La Land,” says. “So I knew as soon as there was a basic theme composed, I had to basically start learning new things and ways to make it sound different.”

Chazelle suggested a theremin early on, so Hurwitz picked one up and started learning how to play it. He got some vintage synthesizers, like a 1968-model Moog, and began learning by way of YouTube how modular synthesis works.

“It’s this old style of synth where you have to patch it with all these cables,” Hurwitz says. “Then I started playing around with other production stuff, things that we would use to process the orchestra and make it sound different. We knew we were going to record a big orchestra for it because we needed it to be big and emotional, but we didn’t want it to sound like a traditional orchestra.”

Hurwitz had never really produced music in the past, so he had even more to learn in order to develop the music in a unique way. He put all of the strings through a couple of processes that gave it a kind of “shakiness” that he thought felt organic to the way Chazelle and Sandgren were shooting the film.

“Neil is so outwardly steady, but there had to be nerves there and I thought that maybe spoke to how he was feeling,” Hurwitz says. “And also, emotionally, he’s fragile, more fragile than he lets on.”

Hurwitz became something of a mad scientist on the project. For example, he recorded all the strings — violas, violins, cellos — separately and ran them through a rotor cabinet that housed a spinning speaker. He then re-recorded the playback as they moved the cabinet around the room, placing it where the actual players had been.

“That gave it this weird, other-worldly kind of flutter to it,” he says. “Then I put it through a tremolo to give it the second layer of flutter, and then violins, basses, cellos were all given different rates of flutter. So there were all these flutters that were in conflict with each other.”

The result is something, indeed, completely different from his previous collaborations with Chazelle, and an element of the film that accounts for a considerable amount of the story’s emotional impact.