Behind The Scenes Part 1: Everything You Didn’t Know About Sound In Movie Production

If you’ve ever watched a rough cut of a film before the composer and sound editors get their hands on it, you know that it is a COMPLETELY different experience than watching a finished film. A great scene can feel weak or boring before the music is added and even worse if the recorded sound is choppy, unleveled and not intelligible. Here is an example of raw footage from the “Cantina” scene in Star Wars:



Unedited Star Wars Cantina Scene by chanoy

You can hear that the background bar voices are weak and the dialogue sounds very poor. One of the reasons that movies sound so good on your home theater is that countless hours have been spent cleaning up all that messy audio and creating new sonic elements during the post-production process. This is part of the very important process of “sound design” during post production and where the audio starts to comes alive.

Many people think that sound design is merely adding sound effects to a film, but that’s the equivalent of saying that cooking is just heating water. There is an immense amount of artistry that goes into shaping the full soundstage of a film. The job of a sound designer (sometimes called “Supervising Sound Editor”) is to amass all of the non-musical sound elements and blend them into cohesive whole that drives the narrative. That can involve manipulating sounds from the set (field sound), editing dialogue, recording all the footsteps & movement sounds (Foley), producing the background sounds, and creating unique effects from scratch. It’s pretty incredible to think that every sound in a movie has been exhaustively analyzed, isolated and approved. Now, let’s break down this process for further exploration.

The Source: Field Sound

During the film production there is a “field sound” team that records all of the sound that occurs on set. This is done with a combination of boom and lavalier (lav) mics. Booms use an extremely directional microphone known as a “shotgun mic.” These are held out of view of the camera (most of the time!) and are attached to a long pole (the boom), so they can be held over the actors. In cases where there is a wide shot or an area a boom isn’t suitable, lav mics are used. They are same kind of microphones that newscasters wear and due to their small size, lav mics are great for hiding in clothing or in a plant in order to pick up dialogue and remain out of view. However, they can also be susceptible to fabric movement where the sound can get muffled if they aren’t placed correctly. All of this audio gets delivered to the sound designer in its raw form.


Once the film is edited, the dialogue must go through an extensive process to make it sound natural and smooth. The sound designer may or may not have a dialogue editor to take care of this aspect of the film, but it is an essential part of the process that must result in clear, intelligible speech. To be frank, there are many factors that can cause the audio received from the set to be quite a mess. Words can be indistinct, distorted or have other rogue sounds on top of them that require heavy doctoring. Sometimes dialogue from another take may have to be used because the preferred shot’s audio is unusable. Here is a quote from George Watters, the supervising sound editor on Star Trek II, III and VI:

On the sets of the Enterprise, the plywood was creaking every time Commander Kirk walked by. That was one of my big gripes in Star Trek VI. When sets are built, they should make sure they are solid so there is no creaking from plywood, because then we have that noise under all the voices on the production tracks, and you have to bring the actors back for looping. It will cost more to get the actors back to fix it than it would to build it right in the first place. You don’t want to replace close-up dialogue, and many directors object as they would rather live with the noise in order to save the original dialogue.

If there are no other takes that can be used or if there is background noise that can’t be edited out, the dialogue will have to be re-recorded in a process called Automated Dialogue Replacement (ADR) or looping. This requires the original actor to return months after filming to record their lines again, matching the original performance. As you can imagine, this is not always an easy task and the skill level of actors in this respect can vary quite greatly. Besides the potentially lengthy endeavor of getting an actor to duplicate their performance, another difficulty is getting the sound to match with the original dialogue. A fun game I play with myself when watching movies or TV is picking out ADR’d dialogue. If it’s not done well, it really sticks out like a sore thumb! You’ll hear someone speaking with a natural tone in a scene and suddenly there’s a line that sounds like it was recorded in a different room, on a different microphone or even by another person. Think of all the R-rated movies that get edited for TV where every “bad” word is replaced with a different “clean” word that’s clearly not what they said and sounds completely different than the rest of the dialogue. That’s usually because time constraints or budget don’t allow for the necessary steps to equal a good performance. But, even on big budget films there can be as much as 60-70% of the dialogue replaced. All of this must be put together, matched to the onscreen performance and made to sound like it’s all from the same place.


Foley is the process of adding or replacing sounds that occur onscreen. Much of what you hear in a film, such as footsteps, doors, clothing swishes etc., are the work of post-production Foley artists. While the actor may be wielding a sword or bat onscreen, often these props are fake so they’ll need some help to make them seem real. Also, that metal floor they’re walking on or marble counter-top they just set their drink on is most likely made of plywood painted to look like a specific surface. In addition, the sound crew on-set is primarily concerned with capturing the dialogue and in fact intentionally try to eliminate any other sound from being captured. Usually, the Foley process will be divided into “footsteps,” “movement” and “specifics.”

First, they’ll go through and create every footstep throughout the movie. Although there are tons of sounds available in sound libraries, is it usually faster and more accurate to recreate these sounds on a Foley stage. Here, the actor’s onscreen activity is performance matched by a Foley artist using an array of different materials. There are many different floor surfaces, splash-tanks and an array of ordinary looking junk. Watching playback from the film, they will literally walk in-place on gravel, dirt, tile, stairs or whatever is necessary to perfectly match the actors walk. Then, they’ll reproduce any necessary body movement. This includes the creak of a leather jacket, the swish of pants while walking, removing a pair of gloves and any scratches, pats or other body movement. Finally, anything that’s not a footstep or body movement will fall under specifics. This can be anything from a punch to the face, a guy falling through a glass window to little sounds like faucets, door knobs or a rusty old bicycle.

While Foley often uses completely different items to portray the events onscreen, sometimes things can get pretty messy when horror movies need their sound effects. Crisp cabbage and celery can be good substitutes for a variety of bone breaks, but when you need a more authentic sound, only the real stuff will do. For the films in the Human Centipede series, the sound designers elected to bring in actual animal parts (after covering the sound booth with plastic) to create many of the horrific sounds like breaking fingers and squishing body parts. Obviously, this adds an authenticity to the events portrayed onscreen, as well as an enormous cleaning bill!


In addition to the sounds being made by actors and machines onscreen, the sound designers will need to produce the background sound as well. This palette includes all of the ambient “location” sounds. Could you imagine being on the bridge of the Enterprise in Star Trek without hearing that cool hum and beeping? A walk through the forest will need to have crickets or marsupials added to sound authentic. The light wind of a ghost town, or swirling wind on a mountain top are all sounds that are provided during post production. If these can’t be authentically pulled from a sound library then it will be necessary to go out and record these sounds. Often going into the field to record new sounds is par for the course, but it’s yet another customized element that needs to be created.

The other part of background sound includes what‘s known as “walla.” This is the recreation of background crowd ambience. When you have a scene at a restaurant, the background conversations and drink clanking will usually need to be added. The various murmurs of background speech are provided by a group of actors improvising conversation that is suited to the environment, language, etc. Most often this “speech” will be gibberish, meant only to sound like background noise. A common technique is to repeat the word “rhubarb” over and over again. The next time you see people speaking in the background, see if you can pick out a “rhubarb”!


Most early sound effects were created by the orchestra (think Looney Tunes) where a cymbal crash would accompany someone running into a wall or by specially constructed musical devices. By the early 1940’s and 50’s advances in recording techniques led to a style known as musique concrete. This was a form of electroacoustic music that relied on the manipulation of recorded sound through various filters, looping devices, tape editing and early synthesizers. Using “non-musical” and synthetic sounds created a new landscape for composers and blurred the lines between what was considered sound and what was music.

Even though there are millions of sounds available within “sound libraries,” often sound designers are called upon to create unique elements for things that have never existed such as magical, supernatural or alien events. Gary Rydstrom, sound designer for Jurassic Park, discusses how he came up with the sound for the Velociraptor: “The first sound was a dolphin we recorded underwater, and it made this high-pitched scream that was really horrific. And then I would combine that with a walrus. The walrus had a deep, resonant chest cavity roar and between the two, it blended into a single scream that sounded like a scary animal who was also big.” This is a prime example of how the sound design blends elements you would never normally put together in order to create a new sound.

One of the best examples of sound design is the film Wall-E. Here Ben Burtt does a masterful job of storytelling using sound. As with all animated films, there are no source sounds to work with. Every environment and non-dialogue element must be created and made to seem natural. In this case, he had to create the “voice” and personality for each of the robots. The proposition of coming up with a robotic language comprised solely of sound might seem daunting to some, but Ben Burtt is an expert in this arena. After all he created the sound of R2-D2, all the other droids & aliens from Star Wars, and the voice of E.T. He discusses how some of the sounds were created for Wall-E:

There were more sound files in Wall-E than any single feature film I’ve ever worked on, about 2500, because every character has a set of sounds and there are lots of movement and lots of dense activity. Stories of sounds, well let’s see – Wall-E’s treads, he drives around, he goes different speeds. When he’s going slowly, he makes a little whirring sound and that is the sound I heard it actually in a John Wayne movie called Island in the Sky on Turner Classic Movies. There was a guy turning a little generator, a soldier generating power. I said I like that generator sound, that is cool, and so where can I get one? I found one on eBay. I bought it. It came in its original 1949 box so we could take that into the studio and perform with it to tailor it to the speed of Wall-E. But that’s only good for when Wall-E is going slow.

When Wall-E is going fast, he needed something higher pitched and more energetic. Once again, I went back through my memory of things. I had recorded bi-planes a long time ago for Raiders of the Lost Ark. The old 1930s bi-planes have an inertia starter. It’s a mechanical crank that cranks the engine up. You do it by hand and then clutch – you connect it and it makes a wonderful whirring sound. So I thought I want to get that and do more with it. I couldn’t bring a bi-plane into the studio but on eBay I found an inertia starter, bought that again, and brought it in. So we built these props for many things. You know, it’s a tradition in animation to have sound effects machines. This goes back to the earliest days of Disney cartoons — like wind machines and blowing machines and things like that. We actually built several things so we could perform Wall-E sounds that way.

Clearly, the depth in which some go to create these fantastical worlds of sound is far deeper than most of us can imagine. This is the beauty of what good sound design can bring to a film and serves as part of the foundation to an incredible sounding theater experience. When done properly, you’ll never notice this part of the filmmaking process, but it is undoubtedly integral to the exceptional quality of modern movies.


Trivia: A classic sound effect known as the “Wilhelm Scream” has been used over and over again in countless films. It’s a favorite of sound designers and filmmakers to sneak into the picture and has been used throughout Hollywood since the 1950’s. You can check out a link demonstrating many of its uses here: The Wilhelm Scream Compilation.


Read the rest of the series:

Behind the Scenes Part 2: The Score

Behind the Scenes Part 3: Mixing



Sound Design – Star Wars Episode II (Full)
Foley Artist Gary Hecker
Ben Burtt – Wall-E Pt. 1
LOTR 1 – Sound Design
The Sound of Transformers 3


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