4.2.2: Sound Mixing

Exploring the Art of Sound Design

Once all of the sound editing is done and matched up with the image, the whole process moves to the sound mixer to finalize the project. And if you’ve ever wondered why there are two Academy Awards for sound, one for sound editing and one for sound mixing, this is why. (Or maybe you’ve never wondered that because that’s when you decided to grab a snack. I mean, who pays attention to Best Sound Mixing?) Sound mixers must take all of the various sound elements brought together by the editors, including the music composed for the score (more on that later), and balance them perfectly so the audience hears exactly what the filmmakers want them to hear from shot to shot and scene to scene.

This is a very delicate process. On the one hand, the sound mix can be objectively calibrated according to a precise decibel level, or degree of loudness, for each layer of sound. Dialogue within a certain acceptable range of loudness, music in its range, sound effects in theirs. Basic math. On the other hand, the mix can and should be a subjective process, with actual humans in a room making adjustments based on the feel of each shot and scene. Most of the time, it’s both. When it’s done well, the audience will feel immersed in each scene, hearing every line of dialogue clearly, even when there are car crashes, explosions, and a driving musical score.

For example, check out this deconstruction of the sound design from a single scene from The Bourne Identity (2002):^[1]

Sound mixing is one of those technical aspects of filmmaking that has evolved over the decades, especially as the technology for sound recording and reproduction has changed in more recent years. Starting with the birth of cinema sound in 1927, movie houses had to be rigged for sound reproduction. Which usually meant a couple of massive, low-quality speakers. But by 1940, sound mixers were already experimenting with the concept of surround sound and the ability to move the various channels of sound around a theater through multiple speakers to match the action on screen.

As the century rolled on, newer, high-fidelity sound reproduction found its way into theaters, allowing for more sophisticated surround sound systems and, consequently, more work for sound mixers to create an immersive experience for audiences. George Lucas introduced THX in 1983, a theatrical standard for sound reproduction in theaters to coincide with the release of Return of the Jedi. In 1987, a French engineer pioneered 5.1 surround sound, which standardized splitting the audio into six distinct channels: two in the front, two in the rear, one in the center, and one just for low bass sound. As recently as 2012, Dolby introduced Dolby Atmos, a new surround sound technology that heightens the available options for sound mixers. Now, sound can appear to be coming from in front, behind, below, or above audiences, creating a 3-D aural experience.

And every element in the final soundtrack has to be calibrated and assigned by the sound mixer. Check out how complex the process was for the sound mixers on Ford v Ferrari (2019):

Finding the right mix of sound is critical for any cinematic experience, but one element that many filmmakers (and audiences) neglect is the use of silence. The absence of sound can be just as powerful, if not more powerful, than the many layers of sound in the final track. Silence can punctuate an emotional moment or put us in the headspace of a character in a way that visuals alone simply cannot.

Check out how skillfully Martin Scorsese uses silence throughout his films:

Of course, in most of these examples, silence refers to the lack of dialogue or a dampening of the ambient sound. Rarely is a filmmaker brave enough to remove all sound completely from a soundtrack. Dead air has a very different quality to it than simply lowering the volume of the mix. But a few brave souls have given it a try. Here’s French New Wave experimental filmmaker Jean Luc Godard playing an aural joke in Band à part (1964):

It’s not actually a full minute of dead air – it’s more like 36 seconds – but it feels like an hour.

Compare that to this scene from the more recent film Gravity (2013):

That was also 36 seconds. Perhaps a little wink from the director Alfonso Cuaròn to the French master Godard. But both are startling examples of the rare attempt to remove all sound to great effect completely.