What are Diegetic & Non-Diegetic Sound in Film?

Diegetic vs non diegetic sounds in film featured image

Published: December 3, 2019 | Last Updated: October 5, 2024

The term diegesis is connected to the narrative and is originally found in the work The Republic by Platon. The term has undergone multiple transformations within academia throughout the years, and I won’t go into all the different theoretical nuances here. Instead, I’ll refer to English Professor Dino Franco Felluga, who defines diegesis as:

”A narrative’s time-space continuum, to borrow a term from Star Trek. The diegesis of a narrative is its entire created world. Any narrative includes a diegesis, whether you are reading science fiction, fantasy, mimetic realism, or psychological realism. However, each kind of story will render that time-space continuum in different ways. The suspension of disbelief that we all perform before entering into a fictional world entails an acceptance of a story’s diegesis”

Felluga 2012

In other words, diegesis is the entire narrative world created in a single film and across multiple stories across time in a shared universe.

Consider franchises such as Star Trek, Star Wars, or the Marvel Universe, where different stories develop across different timelines, settings, and even in different media (comic books, movies, books, animated movies, toys, and more).

With a definition of diegesis, let’s examine what this has to do with sound in film.

Diegetic and Extra-diegetic Sound and Music in Film

Diegetic sound (or music) is sound that originates from within the narrative of the film.

If a gangster fires a gun, the sound of that gun is diegetic (also if the sound is a sound effect, which is added in post-production). The point is that the sound of the gun originates from within the film narrative.

Likewise, it is considered diegetic music when the pianist Sam – “Play it again, Sam” – plays “As Time Goes By” at the bar in the movie Casablanca.

But when you hear the score of ‘The Empirical March’ by John Williams in Star Wars, it is not part of the narrative and thus extra-diegetic or non-diegetic, whichever you prefer.

Now, I could go into an academic discussion about whether or not there’s a difference in nuance between extra-diegetic and non-diegetic, but that would be beside the point for this article.

What is important to understand is that extra-diegetic sounds and music are not a natural part of the film’s narrative but something extra – a sonic context – for the film.

If Darth Vader had blasted ‘The Imperial March’ from the speakers of a boombox at the bridge of the Death Star, the composition would have been part of the film’s diegesis, and thus diegetic sound instead.

On-Screen Sounds and Off-Screen sounds.

Like characters and objects, diegetic sound can be placed on-screen and off-screen, i.e., inside or outside each frame in the film.

Effective use of off-screen sounds is a great way to make each frame – or the screen – seem bigger than it is.

For example, you might show the character in your short film walking down a dark country road when you hear the sound of a car approaching from outside the frame.

In this case, the car’s sound is diegetic off-screen. But as soon as the car enters the frame and stops next to your protagonist, the sound is transformed from diegetic off-screen to diegetic on-screen.

Likewise, if the car drives from on-screen to off-screen, the sound transforms from an on-screen diegetic sound to an off-screen diegetic sound.

Your typical extra-diegetic sound score is always off-screen, as it isn’t part of the diegesis.

Likewise, if you do a voice-over for a documentary, animated explainer video, or commercial, the voice-over is also extra-diegetic off-screen.

Below, I’ve created a small table with a couple of typical examples of the different types of sound found in each type. Remember that sounds can easily jump from one cell to another as the framing shifts in a scene.

Relationship to Story/ScreenOn-ScreenOff-Screen
DiegeticDialogue
SFX made by narrative objects (fx gunshots, tea kettle, car tires, footsteps)
Music (fx from a piano/boombox/discoteque in the film)
Voice-over (fx the voice as the protagonist acting as a narrator’s voice)
SFX (fx creaking floor boards in a horror movie, walla)
Extra-DiegeticSFX added for dramatic effect, but not emmanating from a specific object in the story (fx a stinger or ‘boom’ sound effect when a space ship flies across the screen in a sci-fi movie)Film Score (fx mood music, soundtrack music with popular music tracks)
Voice-over (fx documentary film narrator, explainer video speaker)

Why Should I Care About Diegetic and Extra-Diegetic Sounds?

You can use these terms to analyze what other sound designers have done. That way, you can develop a better understanding of sound in film.

So, even though you might usually just add sounds that fit on the go, being extra aware of how your sounds relate to the story and frame can help you create a better sound design for your movie.

For example, you can introduce objects from off-screen to on-screen to create a more coherent world: if a car is approaching from off-screen, you can use a J-cut to fade in the car sound to the loudness level of when we finally see it on-screen.

Likewise, you can use an L-cut when it drives from on-screen to off-screen.

Second, you can use off-screen ambiance sounds or walla to create a much larger 3D space than what is seen on screen.

Is your protagonist sitting in an apartment in a busy city? Make sure to include some city background noise to give the viewer a sense of the city. Ask yourself whether it is a small-scale town or a big metropolis. Is it a dangerous city (maybe add some sirens)?

If you’re mixing in surround sound, using diegetic off-screen sounds gives you many opportunities to give the viewer extra information about the depth and direction of diegetic objects and characters in a scene.

Analyzing Horror Films is a Great Way to Learn About Sound Effects

Horror movie

Also, if you’re shooting a horror short, using diegetic off-screen sounds is a great way to induce a sense of horror and anxiety in the viewer.

The horror genre often excels at this because you can convey so much information to the viewer through sound.

In the horror film genre, you often don’t want to give away everything about the big monster in the end. Visually, you might reveal scaled skin, sharp teeth, or a knife. – Or you might choose to reveal nothing visual at all.

In that case, using off-screen diegetic sounds is your biggest friend, as you can build a sense of horror from creaking floorboards, howling in the distance, and so much more. You can also give a sense of the beast’s size, e.g., create a bigger monster by adding more bass frequencies to footsteps.

In fact, a diegetic omnipotent and ubiquitous character, consequently placed off-screen and only revealed through sound effects, is called l’acousemêtre (a term coined by film researcher Michel Chion in his excellent book Audio-Vison: Sound on Screen).

You can always reveal the big scary monster in the end with a diegetic on-screen scary sound and maybe an extra-diegetic on-screen stinger to make that jump scary extra efficient.

Analysis of a Couple of Interesting Examples

So, let’s break down a couple of interesting examples so you can understand how analyzing the sound using diegetic and extra-diegetic sounds can help you stress the points you want to make as an instructor or sound designer.

First example: The Truman Show

The first example is from the movie The Truman Show (1998) starring Jim Carrey.

Have a look at this clip:

Listen to the music, which is composed by Philip Glass. You might think this is just your typical extra-diegetic off-screen film score, and it seems to start this way.

However, as the camera shows more of the control room with Ed Harris, we get to see that it is, in fact, Philip Glass himself who sits at the piano and plays while Truman sleeps. The track is called ‘Truman Sleeps’, by the way.

In the scene, we are taken from the diegesis of the TV program “The Truman Show,” which is what is available to the fictional viewers in the movie, to the control room, where Christof (Ed Harris) has the power to “play God” and manipulate the characters in the show.

We are given a “behind the scenes” look at the show and the transformation of the music from being extra-diegetic off-screen to diegetic on-screen sound. The director, Peter Weir, stresses that we, as the viewers, are given a sense of power.

It’s a powerful position, which isn’t available to the show’s viewers and—especially—not available to Truman himself, who is unaware of the whole setup at this point. Also, being let into the control room and seeing the film score being made helps stress the big themes of the film:

If there is a God, we’re all just puppets constantly being manipulated (e.g., by soothing piano sounds). Nothing is random, but everything is controlled by a higher deity we cannot see nor reach.

Then there’s the whole question: what is the reality, and what is fake?

One reality seems real to Truman, and one to the viewers of the Truman reality show in the movie. Then there’s us as viewers, the reality of Christof (the almighty producer), and then there’s the reality of us – the viewers – watching all of these realities unfold in the movie.

We are effectively taken through these different realities by transforming the music from being off-screen extra-diegetic to on-screen diegetic.

There are many other themes in this excellent movie, and the sound design does a good job of reflecting these, but I’ll let you explore more of them to keep this article short.

Second Example: Ferris Bueller’s Day Off (1986) – Opening Scene

The scene starts with the off-screen diegetic voices of Ferris Bueller’s mother and father.

First, we hear the mother over the title—even before we get to the first establishing shot, where we also hear the voice of the father.

Then, we cut to a close-up of Ferris while we still hear the voices of his parents. We still haven’t seen the parents, so they’re still diegetic off-screen. After this, we finally get to see them.

Already, you get the sense that the parents are in the background, not in control, which is true for the rest of the movie.

Cut to around 2:33, when Ferris tricked his parents into believing he was ill. The parents leave the room, and suddenly, Ferris Bueller (Matthew Broderick) turns his head and addresses the audience directly with a, “They bought it!”

By breaking down the fourth wall in this way, as Ferris does many times during the movie, his voice suddenly breaks the walls of the diegesis. It goes from being the on-screen diegetic voice of our protagonist to being a sort of meta commentator on the diegesis.

This elevates Ferris to a position of power, which seems to extend beyond the diegesis. For example, we learn a lot about his friend Cameron’s difficulties through this protagonist narrator.

It is also interesting to note that whenever Ferris is in the diegesis, he lies, steals, and skives school, but when he addresses the audience, he is always honest and sincere.

It’s as if this omnipotent role uplifts his character’s morale to that of God, i.e., the voice of the Father, who always speaks the truth.

Conclusion

I know making videos and films is a very hands-on craft.

But that doesn’t mean you should neglect academic tools and terms, which often offer something unique when it comes to understanding a movie’s essential building blocks.

In this case, the building blocks are the many different ways sound design can stress important elements in your film.

Knowing how to analyze and utilize diegetic and extra-diegetic sound and music can help you raise awareness of your soundscape and create sound design throughout your film. It can also help you better stress important aspects of your film by making you ask yourself the question: “WHY do I want a sound here, and WHAT should that sound be?”

Do you have any good examples of sound design to share? Or maybe some questions or critiques? Let me know in the comments below.

Up Next: Royalty-free sound effects

By Jan Sørup

Jan Sørup is a indie filmmaker, videographer and photographer from Denmark. He owns filmdaft.com and the Danish company Apertura, which produces video content for big companies in Denmark and Scandinavia. Jan has a background in music, has drawn webcomics, and is a former lecturer at the University of Copenhagen.

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