If you haven't had your fill of explosions, chases and invaders from space this summer, Hollywood's latest offering, "Transformers" dishes out an eye-popping, action-packed, computer generated visual feast.
When it comes to giant robots from outer space battling to the death on planet Earth, Hollywood is banking that seeing is believing. But that is only half of the story.
"I mean, you watch a movie without sound or bad sound, it changes it, the whole kind of vibe," director Michael Bay told CBS News correspondent Bill Whitaker. "Sounds are so important to making a realized picture. I mean, these robots are made out of thin air…but it's so realistic and what makes it so realistic is the sound."
Sound is so important to a movie, but so often overlooked, or rather unsung, but sound mixer Kevin O'Connell says it is a collaborative effort which requires meticulous precision.
"What we do is hand craft every single sound and tailor it to whatever image we're seeing on the screen at any particular time," he said.
"Every footstep, every bullet, every gunshot, every sound that you hear is added after the fact," mixer Greg Russell said.
In fact, it takes tens of thousands of different sounds to make a movie like "Transformers." The process begins with supervising sound editors Mike Hopkins and Ethan Van der Ryn. They say they use their imagination to figure out what a robot will sound like. They imagine what each robotic move, footstep and explosion should sound like. Then they assemble a team to create them. They won Academy Awards for the sounds in "The Lord of the Rings" and "King Kong," but squads of giant robots from outer space are a different story.
"Yeah, yeah, I mean definitely a big challenge to have these giant robots and also to have each one of them feel different and you've got guns and planes," Van der Ryn said.
They enlisted Marines from Camp Pendleton near San Diego to provide some assistance. For the big battle scenes they recorded Marines running and shouting. They recorded explosions and fighter jets, but those were the easy sounds.
"The more challenging part is what is the soul — the sort of internal, emotional, soulful sound," Van der Ryn said.
For that they turned to sound designer, Erik Aadahl. He collects a plethora of noises to bring to life what the supervising sound editors have imagined.
"You always hear cool new sounds every day," Aadahl said. "Like Ethan found a pogo stick online and we started playing with it and realized that it had a really neat sound to it."
It became part of the unique sounds of a robot named Bumblebee. So did a car door.
"Took that and slowed it down 25 percent and it sounds like a huge robot footstep," he said.
For a vending machine that comes to life and shoots soda cans, he recorded soda cans dropped from a building.
"It's a lot of fun when you get to make a little bit of a mess on the job," he said.
Speaking of mess, they even create the sound of a dog relieving himself on a robot's foot. They poured water onto a metal hub cap.
John Roesch and Alyson Moore are two of the top Foley artists in Hollywood — so called for the first Hollywood technician to manufacture sound effects. They watch the action on screen and make sounds to exactly match what they see. For example, 20 different sounds are blended to make the robots' footsteps. When star Josh Duhamel is running and the audience hears him running on gravel, it is actually coffee grounds. For the metallic sound of a little robot named Frenzy the team uses common kitchen utensils.
The whole idea is to give director Michael Bay a cornucopia of sounds from which to pick and choose. That's why, when the actors come in, they record take, after take, after take.
In the darkened sound studio, the actors get into character even if the character is the tiny, curmudgeonly robot, Frenzy, voiced by actor Reno Wilson.
"Method robot acting, robotic method acting is a technique that Lee Strasberg didn't talk about much," he said.
From Frenzy to the score, every sound is managed by O'Connell and Russell. Every single sound is downloaded into this massive sound board.
"We have individual control over every single element in this film," O'Connell said. "Everything is separate, so we sit here and hand craft the sounds to create the voice for the film."
"The visuals have to be strong and they are in this movie, but the sound is what brings them to life," Russell said.
"It's kind of like painting, so you know, you've got a bunch of different colors and you blend them together to create new colors. We take frequencies and shape them into what we think they should sound like," Aadahl said.
So the next time you are at the movies, look and listen. There is more on the screen than meets the eye.
Copyright 2007 CBS. All rights reserved.