The heavens will part. The Horn of Gondor will sound. Nerds everywhere will perk up their ears. This Friday and Saturday at Radio City Music Hall, "The Fellowship of the Ring" will be projected onto a 60-foot screen while a 300-piece orchestra plays the film's score. For some people (namely, those who enjoy awesome things) this is a concept that needs no justification. God could have come up with the idea. And perhaps he did.

But the project is not a miracle (though it may end up being miraculous). There is a story, and a set of reasons, behind its creation.

Tim Starnes is a composer and music editor who directly assisted composer Howard Shore with the original score for "The Lord of the Rings" and is now a Steinhardt professor of scoring for film and multimedia. According to Starnes, the idea for the concert evolved from the success of live performances of the six-movement "Lord of the Rings Symphony" worldwide. As those performances often included a visual component — dramatic stills, for instance — the next logical step was to sync the music with the film itself.

But it wasn't going to be easy. As Starnes described, "The film is like a machine. It's not moving at any other speed except [the way] it's gonna move. The music has to follow it."

Blending an entirely organic soundscape with the ruthless exactitude of a film print is inherently unintuitive, like giving therapy to a robot. For one thing, it requires a conductor capable of keeping track of points in the film — lines of dialogue, scene changes, close-ups — where the tempo and feel of the music must change.

"Very few people in this world can do that," Starnes said. "It takes an intense, intimate knowledge of the music — and the film."

Ludwig Wicki, founder and conductor of the 21st Century Orchestra in Switzerland, is one of those people. Wicki will be keeping track of the ebb and flow of the film, as well as his musicians, when he conducts the orchestra on Friday and Saturday.

But Wicki won't be doing it alone. Shore asked Starnes to design a cueing system for the concert based on the Auricle platform, a computer system specially designed for synchronization that provides the conductor and musicians with metronome clicks and visual feedback.

Starnes realized, however, that even this setup was too limited, given the scale of the orchestra.

"Can you pass out 300 headphones to the musicians? It's just not cost-effective," Starnes said. "So we eliminated the whole idea of click. Period. Nothing audible, no audible cues."

Instead, Wicki alone will see "streamers" on a screen in front of him — "literally a white line, moving left to right." When the line reaches the right side, it becomes a point of synchronization to which Wicki will need to try and adhere (think Guitar Hero for a world-class musician). Between these points, which vary in importance and arrive, on average, every five-and-a-half seconds, Wicki will be able to adjust the feel of the music as he wants.

"They're almost like these little buoys. I've given him these little islands," Starnes said. "If something is not aligned, you might feel it. But if it's on — man, what a good feeling!"

That good feeling comes, in part, from Shore's writing process. He meticulously timed each piece of music to the film and even wrote the main theme (you know which one) when he went to visit the sprawling vistas in New Zealand.

Scottish "Lord of the Rings" actor Billy Boyd is also a musician who helped create the sounds of Middle-Earth. Playing Peregrin "Pippin" Took, one of the four principal hobbits, Boyd sang a melody in "The Return of the King" that he wrote and recorded at Abbey Road.

Boyd will make a special appearance at the concert, due in part to his indie-rock band Beecake, which is now touring the East Coast, and also because he doesn't want to miss the score in action.

"It's so vast, it's like three operas," Boyd said. "It's really creating a whole universe; there's a lot of instruments that make you feel like, 'Oh God, where did that come from?' "

Indeed, so much of the score's magic lies in its subtle ability to evoke small parts of a larger world. And even as a logistical behemoth and a bombastic seat-filler, this concert draws from the simple storytelling of silent film: the piano in front, informing us about each character in its beautiful, implacable way.

"I think it's the way film began, and we're kind of returning to that in our new, very Hollywood, very grand way," Starnes said.

Boyd agrees.

"In a world where some movies are getting so cut up and getting $300 million spent on special effects — and if we're all honest, no one really cares about explosions anymore — people are harking back to more of a live experience. This will be a once-in-a-lifetime thing."

"The Fellowship of the Ring" will play at Radio City Music Hall on Oct. 9 and 10 at 7:30 p.m. Tickets ($54 to $150) can be purchased at http://radiocity.com. For more information, visit http://theradiocitylotrconcert.com.