Understanding diegetic and non-diegetic sound

As filmmakers, it can be all too easy to get caught up in the visuals of your film. After all, this is a visual medium and the most important thing is your footage, right? While that’s true, a very close second is sound design. Without great sound design and the use of sound effects, your films simply won’t have anywhere near the same impact. Next time you watch one of your favorite films, mute it for a minute or so and you’ll quickly realize just how important this is!

If you want to become a truly great filmmaker then you need to master the world of sound design and to do this, you need to understand a few really important effects. In this article, we’re taking a look at diegetic and non-diegetic sounds – what are they, how are they used and why are they so important?

What is diegetic sound?

First up, let’s take a look at diegetic sound. Diegetic sound is what you might consider your “classic” sound design – where you go through the process of bringing your visual story to life through the use of sound effects. Diegetic sounds are any sounds that come naturally from the world of the film. These are sounds that your characters and subjects can hear in their world. It could be dialogue, police sirens, the screeching of a train rattling past, the roar of a baseball crowd, or walking sound effects. They don’t even need to be on screen.

Why use diegetic sound?

Diegetic sound is really important because it adds more realism to your films and videos, enabling your audience to really feel like they’re in the scene. Remember what we said about muting your favorite film for a minute? Suddenly, without all of that diegetic sound, you’re taken out of the experience and feel detached from the visuals playing out on the screen. Diegetic sound establishes and creates a world around the characters, drawing your audience in.

Examples of diegetic sounds in films

Diegetic sounds can be found in every film out there. Start watching anything and you’ll hear them within the first minute. Here are a few classic examples you can analyze.

Once Upon a Time in Hollywood (2019)

In Quentin Tarantino’s Once Upon a Time in Hollywood there’s a classic scene where Margot Robbie’s character Sharon Tate is seen dancing to “Good Thing” by Paul Revere & The Raiders. This is a diegetic sound because Sharon can hear the song and is dancing to it.

Jurassic Park (1993)

In the original Jurassic Park, diegetic sound plays a key role in the scene where the T-rex breaks out of the park. The heavy rain sounds are prominent throughout, there’s the rumble of thunder, the “thud” of the dinosaur as it moves along with the water rippling, the dinosaur’s roar, and the creaking of the fence. These sound effects are great examples of diegetic sounds that bring the scene to life.

Top Gun 2 (2022)

Top Gun 2 rightly received a lot of critical acclaim for its excellent sound design. In this tense, edge-of-your-seat scene, diegetic sound plays a key role in bringing the sequence to life. We hear the multitude of different weapons being fired, the cockpit warnings blaring, the roar of the jets, and the dialogue going on between the characters.

What is non-diegetic sound?

Now that you’ve got a diegetic sound definition and understand why and how it’s used, let’s take a look at the opposite – non-diegetic sounds. Non-diegetic sounds contrast with diegetic sounds because they can’t be heard in the world of the film. These sounds are not in your character or subject’s environment, so they can’t be heard by the character or subject.

Why use non-diegetic sound?

Non-diegetic sounds are used by the filmmaker to communicate with their audience directly. They will tend to emphasize mood and atmosphere, or maybe offer up a piece of information to the audience at a key turning point.

Examples of diegetic sounds in films

The most obvious non-diegetic sounds would be the movie scores, sound effects or narration. There are plenty of examples you can analyze throughout the world of cinema.

The Lord of the Rings: The Return of the King (2003)

In The Return of the King, the prominent non-diegetic sound is the epic score by Howard Shore – one of the many standout qualities of this trilogy. In “the lighting of the beacons” scene, the music at first perfectly reflects the tension and suspense as Pippin executes his daring plan, before building into an epic, soaring affair as we’re transported over the mountains of Middle Earth. It’s a glorious scene, made epic by the non-diegetic sound.

The Royal Tenenbaums (2001)

In Wes Anderson’s The Royal Tenenbaums, the narration from Alec Baldwin is framed as if we were reading from a novel – it’s a classic example of non-diegetic sound and without it, the film and story would not be what it is.

Kill Bill Vol. 1 (2003)

Quentin Tarantino loves to use non-diegetic sound effects throughout his films. In a scene from Kill Bill: Vol. 1, we see The Bridge show you at Vernita’s house, and as the door opens, “warning sirens” blast over a flashback along with a dramatic piece of music. This is a sound effect the characters can’t hear.

Fight Club (1999)

There is one caveat to narration being non-diegetic. If the narration is an internal monologue – a voice that’s inside the character’s head – this is no longer a non-diegetic sound, but a specific internal-diegetic sound. Edward Norton’s narration throughout Fight Club is a great example of this specific internal-diegetic sound.

Diegetic sound vs non-diegetic sound

To recap, let’s define what is the difference between diegetic and non-diegetic sounds.

What about trans-diegetic sound?

There is a third term you should know – a hybrid of diegetic and non-diegetic sound. Trans-diegetic sound is when a sound starts off as one, then transitions into the other.

Trans-diegetic sound examples

You can find plenty of trans-diegetic sound examples throughout cinema. A common way for it to be used is through music.

The Lord of the Rings: The Return of the King (2003)

In this scene from The Return of the King, we see Pippin begin to sing a song on screen. This is a diegetic sound, clearly. However, the scene then transitions to show Faramir and his doomed comrades riding toward Osgiliath. Pippin’s song continues to play over this scene, becoming a trans-diegetic sound because it’s clearly transitioned.

Once Upon A Time in Hollywood (2019)

In this classic scene from Once Upon a Time in Hollywood, we hear the 93 KHJ radio station tuning in as Cliff drives away, suggesting he’s listening to the radio in his car. This is a diegetic sound. The song then plays over a sequence as dusk falls upon Los Angeles, and we see various characters heading home, becoming a non-diegetic sound. At the end of the sequence, Cliff and Rick arrive back home, and the song transitions back into diegetic sound playing on the radio that switches off with the car – something the characters can hear.

Storytelling with sound

Now that you understand diegetic and non-diegetic sound (not to mention trans-diegetic and internal-diegetic sound), you can fully appreciate just how important the use of sound design is when it comes to conveying a story. From voices SFX to royalty-free music and everything in between, you can’t make a great film without great sound.

On one hand, diegetic sound is used to really bring a scene to life. It creates a world and draws the audience in with realism. Meanwhile, non-diegetic sounds are used to affect the mood and emotions of an audience, delivering key information and messages to them at turning points in the story. When you use both together, you create a much more accomplished, successful film!

Take the time to study and analyze the use of both throughout your favorite films, and look to use them in your next project!