Let’s Hear It for Sound Effects : Film: The tricky business of sound is so essential to a film’s success that the academy has been handing out Oscars for best sound since 1929.

Five Nazi soldiers rev their motorcycles, roaring and screeching around twisting roads. Dust whirls as they pursue Indiana Jones and his father. Our hero knocks an oncoming Nazi off his bike and the riderless motorcycle crashes into two others. Next, Indy jams the wheel of another motorcycle, sending the Nazi flying. That chase scene in “Indiana Jones and the Last Crusade” was recorded without sound, except for some dialogue. The final sound track was recorded after the filming was finished.

In fact, in most action movies today, almost all of the original sound is replaced. Most of what we hear in theaters is carefully arranged by sound technicians, working in a studio after the film has been shot and edited.

This is tricky collaboration, and so essential to the overall filmgoing experience that the Academy of Motion Pictures Arts and Sciences has been handing out Oscars for the best sound work since 1929. But after all those years, few people understand how sound is recorded and manipulated for movies, or recognize when they’re hearing something special.

What is it about “Black Rain,” “Born on the Fourth of July,” “The Abyss,” “Indiana Jones and the Last Crusade” and “Glory” that earned their sound teams Oscar nominations from their peers in the sound branch of the academy? What is it about “Indiana Jones,” “Black Rain” and “Lethal Weapon 2” that has them competing with each other for best sound effects editing? And what is the difference between the two categories?

A picture can have hundreds of sound tracks with more than 40 sound technicians involved. These craftspeople cover up an actor’s laryngitis, make a lion’s growl more menacing, and capture the crunch of soldiers feet on sand.

Sound people doubt whether many of the 4,800 academy voters are any better judges of good sound than average moviegoers. When winners in these categories are being announced Monday night, there will be as many refrigerator doors opening per capita in Beverly Hills as anywhere else. But who doubts the importance of good sound in a movie, especially now that consumers’ ears are CD-tuned and take perfection for granted?

The Oscars for sound are usually awarded to four people that nobody outside the business has ever heard of: the location mixer in charge of the sound track that is recorded during the actual shooting of a film, and the three technicians who “mix” the location track with dubbed dialogue, sound effects and music in a studio.

The Oscar for best sound effects editing goes to the supervising sound editor on a film, the person hired by producers to oversee the overall sound operation. The supervising sound editor hires the location sound team and the post-production crew that collects sound effects (a door closing, a bird chirping, a nose breaking) and rerecords actors lines in a studio.

There is overlapping work in sound and sound effects editing and even people in the business often find the Oscar category distinctions confusing. Essentially, there are two crews--the one on location and the one gathering effects in post-production--supplying sound to the three-person mixing crew in the studio. As one veteran sound man said, the mixing crew is the “chef” on the job, mixing ingredients and baking a sound “cake.”

“When you bite into it,” says Mark Berger, who won Oscars for his mixing work on “Apocalypse Now” and “Amadeus,” “it should be a lovely cake with all the ingredients in perfect harmony.”

Berger emphasized how hard the rerecording mixers work to make the sound invisible.

“If people notice something doesn’t sound right, then the bubble of illusion bursts and people realize it’s all fake.”

“The power of sound is in its invisibility,” said Walter Murch, who also won an Oscar for “Apocalypse Now.” “If it’s overt and becomes the focus of things, it loses its power. That’s why there’s an in-built weakness asking 4,000-plus members of academy to decide what is best sound and sound effects editing. If it’s the best sound job, voters shouldn’t notice it.”

The award for sound effects editing is given only in years when members of the academy’s sound branch think there was a sufficient number of worthy contenders. Sound effects are important to all movies, and sometimes, the subtlest effects are the most effective.

“Adding that one simple sound effect which gives the scene a subtle emotional impact without the audience being aware of the manipulation--that’s where the challenge lies,” says Oscar-winner Richard Beggs, who will be working on the sound mixing of “The Godfather, Part III” when it finishes filming this spring.

But these sound experts acknowledged that loudness does get the academy’s attention. This year’s slate of sound nominees are action pictures with busy tracks filled with gunshots, explosions, car and motorcycle chases. Subtler efforts, as usual, were ignored.

“A dialogue film like ‘Driving Miss Daisy,’ is very understated in sound, isn’t showy and doesn’t attract attention,” says Berger. “Even though it may be a pleasure to listen to, a film like ‘Daisy’ wouldn’t normally be considered for best sound. . . . While films like ‘Glory’ allow for big, loud sound, you can only pour so much sound into ‘Daisy’ before it gets in the way.”

The best sound award can reflect exemplary effort, but sometimes it is gratuitously handed to a picture because it won best everything else--the “coattail effect,” says Murch. “When a film seems to be getting a lot of other nominations, even if academy members can’t remember the sound, they tend to check the box.”

Which of this year’s crop of nominees impress their colleagues? The sound effects in “Born on the Fourth of July,” when Tom Cruise is fired upon by the Viet Cong, sounded authentic and were nicely choreographed, said Richard Hymns. “We hear the throbbing blades of a helicopter, explosions, machine gun fire, a very ‘Apocalypse Now’ type of sound.”

“Black Rain,” which was nominated in both sound categories, opens with Michael Douglas and a street kid racing motorcycles. “The excellent sound communicates the visual excitement,” said Hymns. “The revving motorcycles sounds made the race seem faster than it really was. Isolating the sounds of each motorcycle--the screaming gear changes, slowing and skidding at the right moment--gave each bike a distinctive sound. That’s difficult.”

Sound can help keep a story clear. The Nazi motorcycles in “Indiana Jones” were made to sound different from Ford and Connery’s motorcycle and side car.

“The good guys and bad guys are given distinctive sounding motorcycles, that sound larger than life, just like the Indiana Jones character,” explained Hymns. “That helps the audience from getting confused about what’s happening.”

“Effects and music can help drive the emotional structure of the movie forward and make it like an ‘E’ ride,” said Jay Boekelheid, who won the best sound effects award for “The Right Stuff.” “In loud, exciting genre melodramas, variety and intensity of sound can enhance the emotional involvement of the audience.”

Both “Indiana Jones” and “Lethal Weapon 2” are huge sound effects movies, with well thought-out and well-mixed sounds of explosions, shooting and chasing, Boekelheid said. “In one scene in ‘Lethal Weapon 2,’ Mel Gibson pulls a house off its foundation with his pickup truck. The truck straining, wood cracking, explosions, the sounds of the house sliding off the foundation--all increase the vicarious thrill of both triumph and excitement.”

Yet, neither film uses sound to break much new ground, said Boekelheid, who referred to both pictures as “money machine sequels” and “cliched American action movies.” Both sequels demand sound effects similar to their predecessor movies, otherwise audiences would be disappointed.

“The Abyss” presented sound problems that were different from those of the other best sound nominees.

“When you’re trying to sell something patently unreal instead of replicating sounds of shots and car chases, you have a real challenge,” said Boekelheid. “The Abyss” sound was difficult because much of the movie takes place in unreal situations--underwater--which the sound people had to make real.

“You don’t hear very much when you’re deep underwater. With relatively slender means, they used score and sound effects to invent mood and support the supernatural element. I believed in the water creature.”

Veteran sound editor David Bartlett said “Glory” had a fascinating sound track that mixed overpowering Civil War pyrotechnics in a way that did not interfere with the film’s music or dialogue.

“On screen you saw the firing and off screen, you heard the battle raging,” Bartlett said. “It was cut and mixed delicately and tastefully so it didn’t conflict with the drama. They got the rifles of the period and made them sound even more dramatic than they do in real life.”

As for predicting which film would win, the sound experts said it’s anybody’s guess.

“There’s often no rhyme or reason for the best sound award,” said Beggs, adding that people have an undeveloped, narrow idea about what good sound is.

“Our culture is aurally illiterate,” he said. “We don’t really use our hearing to the same degree we use our eyes.”