New York ? There’s something wrong in “Spider-Man Turn Off the Dark” — and only Julie Taymor can hear it.

An advertisement adorns the 43rd street side of the Foxwoods Theater on 42nd street in New York on Tuesday where preparations are under way for the opening of “Spider-Man: Turn off the Dark” on Dec. 21.

“Stop a second,” she says inside the Foxwoods Theatre in Times Square during a recent rehearsal of the much-delayed show. “We need a sound effect.”

The swelling music abruptly stops. The five actors on stage — including Reeve Carney as Peter Parker/Spider-Man and Jennifer Damiano as Mary Jane — become still. The stage lights end their dance.

Taymor’s right: The sound of an angry door slam wasn’t heard.

“We’re on it,” says a sound engineer.

There’s naturally much to get done before the costly and complicated show opens on Dec. 21, but a recent visit revealed a methodical and remarkably calm production.

Michael Cohl, the lead producer, is asked how it’s all going. “Very complicated, very quickly and very slowly — all at the same time,” he says with a weary smile. “We’re fine. We’ll be there.”

The musical has been in the works for more than six years, starting with an announcement about the show in 2004. Since then, producers have come and gone, and so have some cast members — Evan Rachel Wood and Alan Cumming were once cast as Mary-Jane and the Green Goblin.

Spider-Man may be the hero on the stage, but it is Cohl who might be considered the production’s savior after he came in and financially stabilized a musical that had been dogged by money problems.

“The budget’s OK,” he says. “It’s a new budget every day.”

When open, this reported $60 million show will have 41 cast members, 18 orchestra members and about 18 new songs by U2’s Bono and the Edge. It will have as its main lead a singer in a rock band whose biggest acting credit so far is in Taymor’s upcoming adaptation of “The Tempest.”

Yet there seems no panic, no screaming. The cast seems loose, the engineers unruffled, the pauses between resets without tension. Someone on the technical side even has her tiny dog on her lap, its head bathed in the light of a computer screen.

Between scenes, the Cirque du Soleil-designed aerial technology is practiced. “OK, we’re going hot!” comes the warning. A moment later, a stuntman in a harness soars over the crowd at 40 mph, looping huge circles that make even the jaded gasp.

The scale of it all hits you as soon as you enter the massive theater, which will seat 1,960 when ready. The orchestra section’s seats have been yanked up to make room for dozens of makeshift boards acting as desks, crammed with laptops, phones and monitors. The balcony is packed with hulking equipment blinking tiny LEDs. It resembles a NASA control room.

At the center of it all is the flight director, Taymor, the director and co-book writer. She often leaves her perch in the center of the rows to wander about, communicating to all through a microphone attached to a headset. Everyone calls it the “God mic.”

For several hours on this day, Taymor and members of her award-winning team — including lighting designer Donald Holder (“South Pacific,” “The Lion King”), costume designer Eiko Ishioka (Francis Ford Coppola’s “Dracula”), sound designer Jonathan Deans (“Fosse,” “Ragtime”) and set designer George Tsypin (“The Little Mermaid”) — practice and tweak a scene from early in Act I.

In it, nerdy Peter Parker’s glasses are broken by bullies outside his high school (the fictional Queens High School). On his walk home he sings the mournful “Anywhere But Here” and joins up with Mary Jane, his neighbor and crush. They trudge along on a circular conveyor belt built into the stage.

The sets change as Carney and Damiano — who was in “Spring Awakening” and earned a featured actress Tony nomination for “Next to Normal” — walk on the conveyor belt. A small train chugs along on tracks high above them near the rendering of a bridge.

Huge panels depicting houses along the route open and close as if a comic book is being read. It’s all drawn in bold, pop art style that overemphasizes angles and perspective.

“Peter,” Mary Jane says as the couple end their walk and stand in front of their respective houses. “You’re a good person.”

“Yeah, well,” he answers. “I don’t know what that gets you.”