The 4 layers of a motion picture soundtrack

Any motion picture soundtrack (whether for film, animation or game) is a composition of four different elements. I’m not talking about channels here. Of course, a soundtrack can come in many formats (stereo, 5.1 surround etc.). But this article deals with the various types of sound which a soundtrack consists of. This knowledge is crucial for you, if you are a filmmaker or a game developer. Not only does it help you to analyse a soundtrack, you will also be able to express your visions more easily when talking with a sound designer.

1. Music

Probably, music was the first thing that came to your mind when you heard the term ‘soundtrack’. And indeed, music can play a vital role in a sonic experience.

A piece of music can bring motion picture to life by creating emotion. But it’s not only about the music itself. Even timing and volume are important. Certainly, it makes a huge difference wether a movie scene is accompanied with loud or subtle music. For example, in a romantic movie you would expect soft sounds and quiet music to be ubiquitous.

There’s one aspect which many filmmakers don’t have in mind when it comes to film music: The music can be part of the scene or not. If it is part of the scene, we call it diegetic music. The latin term ‘diegesis’ can be translated as ‘storyworld’ and includes all the fictive characters which are part of the narrative. Just let me give you some examples for diegetic music. Let’s suppose we have a scene in which a character of the film plays an instrument or he turns on the radio to listen to some music. In both cases the music is part of the story itself.

By the way: Just because the music is part of the narrative doesn’t necessarily mean that it has to be recorded on set. For instance, an actor might only pretend to turn on the radio by putting his hands on it and turning some knobs. In this case, the audio editor has to add the music to the scene during post production. What’s even more, he has to use effects like EQ, reverb or distortion to create a perfect illusion.

As you might expect, there’s also the counterpart to diegetic music which is called non-diegetic music. This term describes the kind of music which is only audible for the audience, but not for the fictive characters of the movie.

Of course, there can also be a mixture of diegetic and non-diegetic music. For example, the audience could witness a melancholic guitar riff which is absolutely suited for the mood of the scene (non-diegetic). Then, there’s a cut and in the next shot we see that there’s a street musician who plays that particular riff (diegetic).

As you can see: Music alone gives you lots of options for designing a unique soundtrack. However, there are three other components we haven’t talked about yet…

2. Sound effects

I guess that the second thing which came to your mind, were sound effects. And, believe it or not, they can be put into sub categories, too.

First of all, you always have the option to record your sound effects while capturing the sound of a certain scene. Either they are part of the audio track of the accompanying film footage, or you decide to record them separately (which I highly recommend).

The problem is that in most cases those recordings don’t have quite the impact you are craving for. More often than not, they sound too weak and unconvincing, when they are in sync with the picture. That’s when Foley recordings come into play! The term is named after Jack Foley who was a sound-effects artist working on many early Hollywood movies. Foley recording means that you take everyday objects and capture their sounds in the studio while the movie footage is played back to help create synchronisation. The person who performs with these objects is called Foley artist.

Furtheremore, you can use a synthesizer to generate sounds which then are
synchronized to the according scene. And obviously, you can use a mixture of Foley recordings and synthesizer sounds.

OK. We had music and sound effects. What’s next?

3. Dialogue

Could you imagine a movie without dialogue? Even though there might be some movies with no characters talking to each other, the most movies would be totally boring without dialogue. Let me tell you something: Although dialogue editing appears to be unexciting, it is an art in itself. The fact that American production sound mixer David Yewdall described dialogue editors as “Hollywood’s unsung heroes” speaks for itself.

There are quite a few challenges with recording dialogue on set. Maybe the actors are screaming or whispering or there’s a loud background noise like highway traffic. In such cases, the dialogue editor either has to fix the recording — or even worse, he has to record the dialogue again. Therefore, he has to call the actors, so he can record them in the studio. The recording has to be in sync with the picture. Consequently, the actors have a screen where they can see themselves acting in the scene, while their vocal performance is being captured. This process is called ADR (Automatic Dialog Recording).

And there’s another aspect to think about concerning dialogue. Yes, I’m talking about the voice over. Say, you want to have a narrator who tells the story, but should not be seen on screen. Of course, this voice has to be recorded in the studio. (By the way: A narrator is another example for a non-diegetic element.)

4. Ambience

The forth layer of a soundtrack is ambience. This term describes the background noise which every room and any other place has. An ambience can give the listener very important psycho-acoustic information about a setting because every room and every place has an individual ambience.

Fortunately, every sound recording from set automatically contains the corresponding ambience. Nonetheless, it’s worth to have a recording which only contains the ambience as this gives the sound designer more material to work with later in the studio.

Let’s imagine you are producing a game or an animation. You have a sudio recording of the dialogue which on its own sounds very unnatural. The reason for this is the lack of ambience. So, go and make some field recordings which you then can use as your ambience for a specific scence. Another option is to create an ambience with the white noise signal of a synthesizer.

There’s one more thing you have to know about ambience. Even though a soundtrack without ambience sounds unnatural, you can go for that un-naturalness. In the right context, you can use this trick to evoke an unsettling feeling. Have a look at the ending of this short animation film to see what I’m talking about.


A soundtrack consists of four different layers: music, sound effects, dialogue, ambience. But that doesn’t mean that they always have to play simultaneously. For instance, you can fade out an ambience, if the music plays a loud part.

Another important aspect is the question whether a sound or the music is part of the scene. If so, they are called diegetic. If they’re not part of the storyworld, they are referred to as non-diegetic sounds.

If you consider all these apects while crafting your soundtrack, you can use the various elements to form a cohesive whole. And that’s what makes an outstanding soundtrack!

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