What is Post-production Sound for Film?

(Photo credit Jakob Owens, sourced from Unsplash)

Sound is an essential part of the narrative in film. It adds depth to scenes that we wouldn’t otherwise be able to experience.

Even if you are not a sound designer, having a basic understanding of sound design and post-production is key when levelling up your next project. Sound is an omnipresent part of stories, from the time in human history where storytelling was developed; actors and storytellers employed sound through the changes of their own voices and even sounds produced with objects around them to further involve their audiences.

In today’s day and age, a video without audio misses on the immersive aspects of the narrative, and while a film for example, can indeed be designed as a ‘mute’ or ‘soundless’ piece of work and still evoke specific emotions and feelings, we know from the studies of psychoacoustics that our ears are more in tune that we are aware of, queuing us into aspects such as directionality of sound, specific characteristics of the sound we hear [e.g is it a big or small object, is it near or far away, is it a human, an animal or a machine] and making use of this knowledge is as indispensable as figuring out what is the best shot to capture with your camera or how to use colour in the editing room to evoke a feeling in the viewer; in fact, choosing silence is, although it might seem counterintuitive also a sound based choice. For filmmaking, this is where post-production comes in.

So, What Is It?

As one of the longest processes for filmmaking, post-production sound for film is an incredibly important process. It’s where all of the elements from the pre-production sound for film and production sound for film come together to create that final, polished piece of work. 

In this article, we’ll be looking into the main elements of post-production, which are:

1. Dialogue Syncing and Editing

2. Automated or Additional Dialogue Replacement (ADR)

3. Sound Effects Editing and Sound Design (including Ambient Sound Design)

4. Foley

5. Music Editing

6. Mixing

Dialogue Syncing and Editing

Before the picture lock stage, and just after the production sound team has delivered the audio to the film editor, sound syncing occurs. Dialogue sync is usually performed by the film editor when preparing the initial rough cut, having said that, it all depends on the budget allocated to the project and also on the particular challenges of syncing for the particular film, sound editors might assist in this process.

During the production stage of filmmaking, the sound and photography crew must ensure that they are both recording audio and video at the same frame rate. They must have also agreed on a syncing system. A clapper board is essential here too, but opting for an additional helper such as using Jam Sync is not only strongly advised but necessary at this point.

Jam Synchronisation is a mode of device synchronisation that uses SMPTE time code. This allows a slave device to synch its timing from a master device while also having a starting point to carry on timecode counting when the master device might be temporarily unstable.

This synchronisation is achieved in a variety of ways. For example, you can use a Bluetooth-operated Tentacle device or make use of a TC cable to perform an initial sync between devices that might need to be reviewed in order to be maintained every time the devices are turned off and on again.

A ‘Tentacle’ device

Taking these processes into consideration, will ensure that dialogue and other sound syncing occurs with no major issues before moving on to audio editing. Dialogue editing is then conducted after the film editor, director and anyone involved in the film editing have decided on which takes to use. Cleaning and levelling of dialogue track occurs as well as preparation to go into ADR with marks in the session for where new dialogue inserts must occur as well as further editing where effects are required for the dialogue tracks and so on. 

What is ADR?

Automated, or Additional Dialogue Replacement, is an essential part of post-production. It’s used when the current audio is corrupted or can’t be used.

It requires an actor to go into an interference-proofed room. This way, they can record new dialogue that is then properly synced to the video.

During an ADR session, the actor lip-syncs to the footage of their original performance, ensuring that they deliver the same tone and emotion, so as to properly match dialogue to video as seamlessly as possible. Before the recording session, the video footage and sections for where the replacement must occur are prepared, and a setup including a properly synchronised screen, reproduces the video so that there are no delays or inaccuracies when the actor performs the scene once again.

Sound Effects and Sound Design

Once the dialogue is complete, sound effects are added to the scene. 

There are several ways to add sound effects to a scene. Extensive use of sound libraries commonly prevail in the industry which allow the sound effect designer to layer up different sounds until the desired effect is achieved. Additionally and depending on the style and budget of the production, original sound can be captured and also used in the process of layer as well as specific recording techniques in tandem with microphone placement and different materials can also be used to produce unique sound effects suitable for the image.

Sound effects are crucial, since they not only add quality to the scene but immerse the viewer in impossible and inexistent worlds. Take, for example, this fan edited scene from The Matrix. They removed the backing music, leaving only the sound effects, which totally transforms how you watch it. 

‘The Matrix’ without music is a completely different experience

What is Foley?

Foley is the process of creating human-made sound effects, such as footsteps or coughing. These effects are then synced to the actor’s movements on screen, making the scene seem even more realistic. 

Often with Foley, sounds layered on top of the actor's movements aren’t the actual sounds. For example, when someone’s running, this may be someone with a mic slapping flip-flops off the ground.

Foley is often necessary when certain sounds that are captured during filming, simply don’t sound good. This can be due to interference such as noisy traffic or passerbys. In practical sense, the reality is that most of what you hear on a film might be foley created in post-production, as the focus of the production sound mixer is to capture quality dialogue.

Music Editing

Music editing is an important part of the post-production process. Usually, it can be one of the last things your sound design team does, once the syncing and other editing processes are complete, but this is not always the case.

Depending on various factors such as the nature of the project, the music composer level of involvement in the film and even the director’s preferences, the music for the film might be composed even before filming occurs, during filming or up until there is a rough draft of the editing available; composition can also happen all throughout the film development with a series of musical themes composed at different stages of the project. 

So, while in the case of music composed during the post-production stage, the themes might synch with the video editing, in many cases, as the music editor might have a huge amount of musical tracks sort of composed with certain scenes in mind which will need to be puzzled during film and sound editing alongside the director and the composer.

Music Editing can then become incredibly complex and require a back and forth with the film editor to make sure a certain piece matches the editing rhythm. The editing process is there to make sure that the musical vision of the director in conjunction with the beauty of the composer’s work is respected, but most importantly, the job is there to ensure the film is made justice and that it achieves the highest possible quality with a sensible combination of sound, music and silence moments.

From pumping the audience up during a fight scene with a punchy heavy rock song, to having a triumphant sounding score when the hero overcomes an obstacle, or to knowing when to go for no music, a well edited score makes the film.

Editing is a crucial step in sound design (Photo credit Sanjeev Nagaraj, sourced from Unsplash)

Mixing

Now we get to the final stage of the process: Audio Mixing. 

During this stage, the audio levels are balanced so that the audio, dialogue and music layers blend together—without sounding out of place or choppy. Essentially this is when we take all of the previous stages, and put them together. 

At this point it is important to also consider loudness levels. There are several standards for loudness levels, depending on the platform and geographical location where the film will be played, such as EB R128 and ATSC. We will discuss these very soon in an upcoming Let’s Talk About Sound, so make sure you are following our Facebook and Instagram pages!

Everything has to start at the right time and sync correctly to create an appealing, effective and highly realistic audio experience for the viewer but also must be designed to understand where your film will play. Will it be projected in cinemas across the country? Will it be part of the catalogue of Netflix or Prime? The mix will be informed by this, and it will not be unusual to have several mixes, designed to fit the different spaces where your film will be showcased.

Mixing is a crucial and very complex part of preparing your film for audiences, one that certainly requires a blog post on its own but if you wish to know more, let us tell you where to get more information below.

Want to Learn More?

By now, you should have a better understanding of what sound design for film is. If you’d like to learn more, feel free to visit our range of audio courses. They’ll teach you everything you need to know. In particular you may be interested in our class An Introduction to Post-production Sound for Film, which will talk a bit more about all the topics discussed here, including mixing. In the future we will also release a class dedicated to this particular subject so keep posted! 

If you wish to access our range of classes, go here and receive a 30 day free access pass with our referral link.