“In space, no one can hear you scream…” (Alien, 1979)
With regards to the quote from Alien, well… yes and no. All the great space films have established how their very own “world physics,” and Gravity is no exception. It balances the “strict no sound in space rule” of 2001 Space Odyssey and the theatrically blatant disregard of sound physics of almost 90% of Space Films (try to imagine how un-precise it is to actually hear the DeathStar exploding.)
The audience is shown what the movie dynamic for Gravity is going to be in the first 3 minutes. Right from the title sequence where the main theme is played, and an ominous sign stating there is no sound or life in space.
The Theme is played in all it’s glorious loudness and suddenly, everything goes quiet. In this first sequence, very gradually, the Shuttle’s hum is faded in, as well as radio transmissions (with some Country Music). This is done very subtlety, as the viewer is sucked into the world dynamics without knowing and without further need of explanation other than the ominous sign displayed moments ago, that is already receding into oblivion.
It is in the first spacewalk scene where in utmost silence, the astronauts talk via radio, and the audience “gets how things will work”.
Almost all the dialogue heard in the movie is due to radio communication. The only exceptions are inside pressurized ships and the final sequence, when protagonist Dr. Stone is back on Earth. Only here do we hear voices without filtering or fuzz distortion from the radios. This is a very elegant solution to the “there is no sound in space” problem for the dialogues.
Moving on, treatment of the sound of explosions and collisions can be boiled down to a simple question: Is there air?
If Yes: there is sound.
If No: there is no sound.
Or at least no direct sound. This means that anytime Dr. Stone is within a spacecraft that has pressurized oxygen, collisions and explosions are heard. To extend this concept, if the characters are touching something, be it the hull of the ship or a tool, low frequency sound will be transmitted, producing very strong low frequency emissions from explosions, low frequency rumble or low passed mechanical tool noise or “bumping into objects” (often times perceived as mic noise handling). It is also worth noting the great care in which scientific details have been kept very close to reality, such as how fire or liquid behaves in zero-g.
The result of the world physics presented here is that there are very violent action sequences with explosions that generate absolutely no sound. In fact, this same world physics is applied to the video game DeadSpace, wherein the protagonist will only hear low-passed sound (during vacuum gameplay) and whatever sounds are produced by his steps or from within the suit (including recorded human heartbeats), generating more sense of danger, as it is unknown where enemies are or if there are dangers near, very much like Gravity.
In Gravity we are left to only hear the speeding heart and distorted screams of Dr. Stone as she is violently tossed around the surround field whenever these action sequences arise, which brings up another subject: The surround field (or stereo field where no surround system is available).
It is Re-recording Mixer Skip Lievsay’s and Director Alfonso Cuarón’s affirmation that this film is intended for a surround system. As they are not only subject to air, but to radio fuzz as well, dialogues are treated as another different tool for narrative purposes, covered next.
Mix: ADR, SFX & Foley
Sound as a whole is taken into consideration for the “world physics” of Gravity. This is why the following elements are given musical importance, and as such, merit dissection.
In Gravity, dialogue is more than just the words that are said, but as a result of the setting, its overall harmonics in the spectrum and their panning also tell a story (it is the “subtext” in a way). Because the audience mostly hears dialogue through radio coms, the mix engineers have taken a bold artistic license with how dialogue is edited & mixed, and it follows anything but the norm.
To start, most of the ADR and Dialogue tracking for space walks and general times where a space suit is worn, was done with lapel mics close to the actors’ mouth, much the same way they would be in the real life.
This first step already yields a gritty recording, which in this case, is fruitful.
The mix and edit engineers then clean up and filter accordingly for the overall sound desired, going for basic shapes, such as Bandpass, HPF and LPF.
(As a side-note, another well used technique that involves the use of filters used in Gravity and other films, such as Saving Private Ryan, is that of using tinnitus-like sinusoidals at around 8KHz along side heavy LPF’s to embody head-trauma or the aftershock of loud explosions, giving the audience a concussed or deafening feeling.)
Now comes the artistic license, being that in times where the character is in near death, or in an action sequence, the engineers mix in fuzz distortion into the dialogue. The end result is almost unnoticeable due to how it organically mixes together with everything else. The audience is brought closer to the actor in his/her life/death scenario and is in short, brought to the edge oftheir seat ever more.
This procedure is surprisingly not as unique as it may feel at first. It is in fact used often when programming video game AI behavior, as is the case with Tom Clancy’s EndWar.
EndWar is a realtime strategy game in which the player must control his own personal army in a war scenario. As stated by Ben Houge, EndWar’s Audio Director, the AI will react whenever the player’s troops are under heavy fire by distorting their radio communications, giving a sonic indication to the player that his troops are under siege. “[The EndWar Team] adjusted the quality of the signal in proportion to the unit’s health, so that as a unit’s health deteriorates, the unit’s radio broadcast becomes more distorted. Providing aural clues to unit type and unit health when a unit speaks is one way that audio supported EndWar’s key mandate of accessibility.“
Furthermore, another element that is present in Gravity that belongs more to the video game world rather than cinema is the use of extreme surround panning.
Prominent software on the market today for video game development, such as Unreal Engine or Unity, will provide from the start, tools that allow for in-world spatialization, as video-games aim to provide immersive environments, where players plunge into a world of sound.
Gravity was of course not dubbed in Unreal Engine, rather mixed for 7.1 Surround Systems and was later enlarged even more through the use of DOLBY ATMOS, which provides “near 3D sound”. Not only was it mixed with these architectures, but the mix pans to extremes. Whereas in a traditional film, dialogue would live in the Center Channel, Gravity’s panning technique follows the character and objects wherever they are on screen. The result is daze and disorientation on behalf of the audience, which is the reason this method is so unused, but in this case, it is the exact reason why it is such a good fit. This is how many video games on the market behave.
Further creative use of dialogue is dynamically changing the filter curves of the dialogue depending on where the camera is. The classic example of this is the “Detached” Sequence, in which Dr. Stone is flung from the Shuttle and is flying off strapped to the extending arm of said Shuttle. She is instructed to detach herself from the arm and as she does so, the camera slowly enters her suit through the glass face plate.
As this happens, the voice goes from rough and gritty to suddenly becoming clear and crisp, no longer filtered or distorted with fuzz (as well as the Ambient Track and Music Track). This is further confirmation of the impact first person has on the film.
Another example of this is the landing sequence on the lake. As water fills the capsule, every moment that water laps and submerges the camera or the character, a very strong low pass filter is applied to the entire mix, even the music. This extends throughout the entire underwater sequence.
Finally, the last scene in which Dr. Stone is on the shore contrasts sonically with the entire film. There is a crisp high end and natural mid and low frequencies, as well as Ambient Tracks of water and wildlife, contrasting sharply with the inhospitable environment she just came from.
SFX & Foley
As has been mentioned, the “real-world” approach of Gravity is infused in all its fibers, including the pre-production and the source tracks for building SFX, dialogue and foley. Among the arsenal of techniques and equipment used to create the SFX & foley of the film, we have:
- Contact (Piezo) Microphones
- Hydrophones (Piezo)
- Lapel Microphones (for ADR)
Going for the source sound with such grit was a very bold move that payed off, as this is the sound intended for the movie instead of going for traditional recording and then having to tweak to achieve “filtered” sound.
Sound Design Applied to Music & Themes
I’ve gone ahead and created sound-alikes for two of the themes in Gravity and illustrated the synthesis methods.
Track 1, Above Earth, serves as the Overture to the film. It sets the stage, presenting the Main Leitmotif, as it reaches it’s climax, and goes dead silent, illustrating the mechanics of the events to come. It employs:
- Additive Synthesis
- Solo Vocals
- Recordings of Rocket Thrusters and Radio Chatter
- Electric Guitar
- Reversed Sound Assets
My Full Mix Sound-Alike:
Compare it to the original:
Obviously more production and energy have gone into the original, but my idea was to capture the essence of what makes the track work.
My Massive Synth Patch:
My Z3ta Sweetener:
Part II of the Above Earth track follows a traditional chorale approach:
My Above Earth Part II Sound-Alike:
Another very interesting track for its musical content and sound design is track 11, Aurora Borealis. It uses a pedal point in it’s top voice, mixing it with radio coms squelching. The high register and constant reiteration with small variations and ethereal backing ambient harmony, gives a very hypnotic and nostalgic feeling, not unlike Erik Satie’s Gymnopedie No.1, albeit with a purist piano approach. Here is an elemental piano reduction of this Track. One of the many ways you could obtain the squelch would be to actually record it (which is more than likely what happened), or recreate it via synthesis. There’s an old, now defunct plugin by (also defunct) Digidesign in the legacy RTAS format called Cosmonaut voice, which other than filtering in a low-fi manner, would also squelch like a walkie talkie.
Be it in video games or in feature films, sound and music play their role in aiding the story. This becomes even more apparent as post production techniques tend to recreate reality discarding most of the production sound. Thus, what we hear is an idealization, a construct for the particular universe the film or video game we are interacting with takes place on.
In the case of Gravity, its unique approach to sound has set it apart. As was mentioned before, for this film, sound in general (the sum of Music, Dialogue, Ambient Tracks, and Foley) borrows elements from other media, in this case video games (sonically and visually).
It will be very interesting to see the interaction of film and video games as they continue to feed each other, as well as how technology will continue to shape the future of music-making. Gravity is a prime example of a feat of Musique-Concrète and Symphonic Music for a wide audience.
The following are interviews showcasing the crew of Gravity, and their approach to sound for the film.