Skywalker Sound
The Making of a Movie Soundtrack

Skywalker Sound is George Lucas's state of the art post production company located in Marin County, California. It is a part of Lucas Digital Ltd., a company that includes Industrial Light & Magic. The business of Lucas Digital Ltd. is to provide the ultimate in visual effects and movie sound design to the film industry.

Skywalker Sound began life as Sprockets Systems in 1980. Back then, it was the company responsible for creating the famous sound effects and soundtracks for the Star Wars movies. Star Wars sound designer Ben Burtt's soundtracks established a new level of sophistication. Knowing that sound is more integral to the movie experience, George Lucas wanted to create better and more involving soundtracks. He hired Tomlinson Holman to investigate the film post production process and to design new and better ways to create movie soundtracks. Tom's investigation into movie sound and its quality took several years, and the end result was the Technical Building at Skywalker Ranch. A happy by-product was the THX Sound System for movie theatres. Tom found that one of the weakest links in the movie soundtrack chain was the quality of the acoustics and the sound system in the dubbing, stage where soundtracks are mixed. The same high performance design approach found in mixing theatres can be found in the over 1500 THX movie auditoriums world-wide. All of the mixing theatres and screening rooms at Skywalker Sound are THX approved.

To better understand the importance of sound (and a high-resolution sound system) to the movie experience, let's take a look at how a movie soundtrack is put together:


Dialogue is, perhaps, the most important element of a movie soundtrack. It communicates key information on the plot and the characters, and it serves to tie the whole narrative structure of a movie together. After all, modern films were first called "talkies".

Dialogue is typically recorded on the set while the movie is being filmed using a variety of equipment (microphones and tape recorders). If the film is being shot on a sound stage, there is a very good likelihood that the dialogue recorded will be useable in the final film mix. However, if the scene is shot on location (high background noise) or the sound stage contains mechanical special effects (wind machines, etc.), the dialogue may become contaminated. At this point, the director or sound designer may require that the actor "loop" their lines.

Looping or ADR (automated dialogue replacement) is the process whereby an actor enters a sound studio and repeats their lines of dialogue in synchronization with the film action. The individual scene is usually shown on a loop of film (hence the term "looping") so it can be repeated over and over. Good ADR is truly an art form. It requires actors to repeat, not only their lines, but their emotions days or even weeks after the scene is shot. During looping, a director may even change lines of dialogue, usually during scenes where the actor's mouth is not fully visible. Quite a bit of time is spent during dialogue pre-mixing to ensure that the tonal quality of the ADR matches the dialogue recorded on the set. Any change in dialogue character or quality could distract an audience.

Sound Effects

While Dialogue serves to make a movie understandable, the purpose of a sound effect is to draw us into the action and to make us believe that we are a part of the movie experience. Sound effects fall into four basic groups:

The First Rule of Sound Design: See a sound; hear a sound. Every time you see some action on the screen, your mind expects there to be a complementary sound. The support of sound effects helps you "willingly suspend your disbelief" and become immersed in the movie experience. This rule is the basis for the first two sound groups: Foley and Designed Sounds.


The film term Foley pays tribute forever to Jack Foley a film sound pioneer from the earliest days of talking pictures. It was discovered that simply having people talk on a screen without any supporting sound effects came across as unnatural. When you see people walking, you expect to hear the sound of their footsteps. Now it's rather difficult to pick up the sound of an actor's footsteps on the set and still keep a microphone out of the picture. He created a unique environment now called a "Foley Stage". In it, artists can duplicate the sound of footsteps, prop handling, or body movement in sync with the picture.

While originally designed to reproduce footsteps on a variety of surfaces, a Foley artist's responsibility now extends to creating everything from the softest sounds of clothes rustling to dinosaur dung. The Foley Stage at Skywalker Sound is extremely quiet (below NC-0) to allow the softest sounds to be recorded. It is also extremely dead acoustically so that no acoustical character is imparted to the sound. That will be added later on in the Foley pre-mix.

Designed Sounds

Frequently the sound of something in the film doesn't exist in real life. It could be an Imperial Walker or the sound of a laser pistol. Because seeing an action without an accompanying sound can cause "cognitive dissonance" (two sensory inputs in conflict with each other - sight & hearing), the audience can be pulled out of the movie's action. Since the state of the art in visual effects keeps expanding to meet the director's imagination, the art of sound design has to keep up. In many instances, great sound design can even make a marginal visual effect seem more realistic.

Many times these sound designs are several different sounds, individually modified, and layered to provide complexity. The sound of the Imperial Walkers, shown here from The Empire Strikes Back, were created by modifying the sound of a machinist's punch press. Added to this for complexity, were the sounds of bicycle chains being dropped on concrete.

Here Ben Burtt is capturing the sound of a hammer on an antenna tower guy wire, which will become the familiar sound of laser blasts in the Star Wars movies.

Creature Sounds

In many instances, alien life forms and even dinosaurs have become a staple of the modern action film. Because many stories now revolve around animals or aliens, it is important that the audience have an emotional connection to these important characters. Under these circumstances, each animal must have an "emotional language". The audience must know intuitively when the creatures are sad, happy, or angry. To do this, the sound designer will record the voices of many real animals, and (in a process similar to Designed Sounds) alter them individually and then layer them to create an entirely new, but believable, creature voice.

On the right, Ben is using the confusion of these walruses (their pool has been drained for cleaning, and they're not happy about it) to expand Chewbacca's vocabulary.


This is the greatest gift that surround sound has brought the film audience. Ambience is the sound of the movie's world. If the scene calls for a storm, you hear rain. If the scene is in a cathedral, you experience the echoes of the characters' voices or the sounds of their action, all around. By recreating a scene's acoustical environment in front of and all around you, the sound designer draws you into the movie, and makes you feel a part of the action.


So, in the world of a movie soundtrack, Dialogue provides the content and Sound Effects provide the realism. The final anchoring point of a movie soundtrack is the Music. Music provides an emotional bedrock for a film. Even before sound was married to picture, cinemas across the world had pianists, organists, and sometimes orchestras to provide emotional enhancement for films. The greatest directors of the day even commissioned great composers to score their films. The sheet music would be shipped along with the print to major markets. While well recorded music can provide dramatic emphasis, it can also make an audience happy or sad. Musical cues can even terrify, to which anyone who has seen Psycho or Jaws can testify.

The Scoring Stage at Skywalker Ranch enables a composer to conduct a suitable instrumental ensemble while watching the film projected on a screen. As with everything in film sound, the music must match the picture.

The Skywalker Scoring Stage not only can accommodate a full symphony orchestra, its acoustics can also be varied by adjusting hidden acoustical panels. These panels can be activated to cover all room surfaces and can reduce the room's reverberation characteristics dramatically. This allows for the recording engineer to achieve the greatest fidelity, without resorting to artificial reverberation. The 48 track digital facility is also in high demand for pop, jazz, and classical recording sessions.


Once all of the sound elements are assembled, they must be edited, cut and spliced into the correct order to match each scene. At Skywalker Sound, this editing process is done on digital audio workstations. The editing process can be very complicated. The "T-Rex smashes the Explorer" scene alone in Jurassic Park contained thousands of edits.


Once all of the sounds are edited to match the scenes, they are pre-mixed. Since there can be many hundreds of individual sound elements in a scene, it is best to group them together by content and mix them into "stems". These stems often follow the basic elements of film sound; Dialogue, Music, and Sound Effects. Frequently, because of their complexity, Sound Effects are not limited to only one pre-mix, but are spread out according to their content: Effects A, Effects B, Ambience A, Ambience B and Foley.

Of course the complexity of film soundtracks sometimes means that you need a very large number of audio tracks. Unfortunately, no one makes a 100+ track audio recorder, so many machines are linked together to provide this capability.

As many machines as are required can be linked together and controlled from the mixing room. All machines are locked to the film projector located in the mixing stage. Skywalker Sound even pioneered the use of tie lines between the Skywalker Ranch facility and remote locations.

Final Sound Mix

Once the sound has been designed, edited, and pre-mixed it is brought together in a movie theatre environment for the final mix. Here, the director, sound designer, dialogue mixer, and music mixer determine the overall quality, character, and placement of each sound element.

The final mix of a film can take two weeks or more, as each scene is replayed over and over again allowing for subtle changes to be noted and made. It is here that the locations of sounds are married to the picture. Sound movement, or panning, is determined here. The level and character of the ambiences is determined. Dialogue levels and locations are set amidst the competition from sound effects and music. Here it all comes together in a controlled environment.

Even though all movie theatres conform to the same standards, it's known that not all movie theatres are perfect. The Mixing Theatres at Skywalker Sound can simulate everything from noisy air conditioning to clipping amplifiers.

Final Checks

Once the quality of the soundtrack is judged (and the computer automation has recorded every adjustment of each fader, each tone control, and the location of each pan), the print mastering begins.

Master tapes are made for each scene. One set of masters is the LT/RT (Left Total/Right Total) containing the 4 channel encoded surround signal. Most films require a 6 or 8 track print master used for 70mm, Dolby SR-D, DTS, or Sony SDDS release. Frequently, a 6 track transfer is made directly to the digital encoder for these systems. Once all of the masters are completed, they must be checked to ensure that the final soundtrack is perfect.

The Stag Theatre (THX Screening Room) located in the Technical Building at Skywalker Ranch is where a mixer, sound designer, or director can experience the final fruits of their work. The Stag Theatre can accommodate all commercial film formats from 35mm flat to 70mm, and it can reproduce all audio formats from mono optical to the latest digital systems. The Stag Theatre (named for the two stainless steel art deco stags framing the entrance) seats several hundred people and conforms to the high standards set by THX. It is quiet, acoustically dead, and there truly is no "bad seat" in the house. It is the site, not only for print master quality control checks, but for Lucasfilm company screenings and the Home THX Dealer Training seminars.

Skywalker Sound: The Future

Films mixed at Skywalker Sound, and its predecessor Sprockets Systems, have won 11 Academy Awards for movie sound or sound effects editing. This is a testament, not only to the facility, but to the hundreds of dedicated artists, technicians, and craftsmen who work there. Winner of 3 TEC Awards and acclaimed by Mix Magazine as the best Post Production Facility for 1992, 1993 and 1994, Skywalker Sound is a place, like its companion Industrial Light & Magic, where technology doesn't limit the imagination of the filmmaker.

Films Mixed at Skywalker Sound

Copyright © 1998 Lucasfilm, Ltd.