Chion's Audiovisual Concepts: Added Value, Synchresis, and the Audiovisual Contract

1. The Audiovisual Contract

Before we can analyze how sound and image interact, we must first acknowledge the fundamental basis on which we perceive them as a single entity. Chion calls this the audiovisual contract. It is an unspoken pact, a perceptual habit, that we as spectators enter into, where we tacitly agree to accept the sound and image presented to us as a coherent whole. We don't consciously perceive a film as two separate tracks—one visual, one auditory—playing in parallel. Instead, we perceive a unified world.

The following reading from a secondary source provides a concise introduction to this idea and to our next concept, "added value."

As the reading states, this contract is the "binding sensorial relationship between sound and image." It is the foundation upon which all other audiovisual effects are built. To explore this further, let's now turn to Chion's own words from his seminal book, Audio-Vision.

In the following excerpt, Chion introduces the audiovisual contract and immediately begins to illustrate its power by discussing how sound influences our perception of something we typically think of as visual: time.

Chion argues that sound doesn't just accompany the image; it fundamentally transforms it. A static shot, which might feel timeless or abstract on its own, is inscribed into a concrete, flowing temporality by the addition of sound. Think of his examples:

• Temporal animation: A smooth, steady sound is less animating than an uneven, fluttering one (e.g., a tremolo string). The texture of the sound infuses the image with a sense of tension and immediacy.
• Temporal linearization: A montage of faces might be perceived as simultaneous reactions. But add the sound of sequential dialogue or laughter, and the images are suddenly locked into a linear, one-after-the-other sequence.
• Vectorization: A sound like a footstep or a water droplet has a natural, irreversible trajectory (attack, decay). This aural "arrow of time" imposes a forward direction onto an otherwise reversible image, creating expectation.

This power of sound to "write" time onto the image is a primary function of the audiovisual contract. It's a prime example of our next concept: added value.

2. Added Value

Chion defines added value as the expressive information that sound brings to an image, creating the impression that this information was already latent within the image itself. It's not simply that sound is added to the image; it's that sound adds value by transforming what we see.

Crucially, this is not a one-way street. The relationship is reciprocal. The image also projects meaning onto the sound, altering how we hear it.

The next section of Audio-Vision explains this reciprocity using several powerful examples from film history.

Chion's examples are potent illustrations of this principle:

• The horrifying screams in Kiss Me Deadly are made terrifying by the visual context of torture.
• The sickening sound of a "crushed watermelon" in The Skin becomes the sound of a child being run over by a tank because of what we are led to believe is happening visually.
• The sound of gargling in Andrei Rublov becomes an atrocious act of violence because it is visually contextualized as the destruction of a human's ability to speak.

In each case, the sound itself is not inherently horrific. Its meaning is produced at the point of fusion with the image. This concept directly challenges the Schaferian notion of "schizophonia." For Chion, the origin of the sound is less important than the new reality created by its combination with an image. The question is not "Is the sound authentic?" but "What meaning does this audiovisual combination create?"

3. Synchresis

If the audiovisual contract is the general pact and added value is the resulting transformation of meaning, synchresis is the specific perceptual mechanism that makes it all possible. Chion coined the term by combining synchronism and synthesis.

Synchresis is the spontaneous and irresistible perceptual phenomenon that welds a sound to a visual event when they occur at the same time.

This perceptual weld happens automatically, often without any logical basis. It is this psychological reflex that allows the entire artifice of film sound post-production—from dialogue replacement to Foley effects—to work. As a sound mixer, you have professionally dedicated yourself to crafting and exploiting the power of synchresis.

Let's read Chion's detailed explanation.

This section is dense with insights directly relevant to your practical experience:

• Synch Points: Synchresis is often concentrated at synch points—salient moments of audiovisual convergence, like a cut, a line of dialogue, or an impact. Chion’s analysis of the punch as the "emblematic synch point" is key. A punch in a film is an event made of sound as much as image; the sound effect gives the visual impact its weight, brutality, and instantaneity.
• Psychological, Not Logical: Synchresis can weld sounds and images that have no real-world connection. Chion notes Tati's use of ping-pong ball sounds for footsteps in Mon Oncle. Because the sound occurs in perfect synchrony with the visual action of walking, our brain forges the connection.
• Enabling Artifice: The principle of synchresis is what gives sound designers and mixers their creative freedom. It is because of synchresis that "for a shot of a hammer, any one of a hundred sounds will do." The goal is not perfect realism, but a convincing and effective audiovisual fusion.

The following diagram offers a conceptual map of how synchresis functions within a spectrum of possible relationships between sound and image, from simple unison to complex counterpoint.

Conclusion

Today we have introduced three of Michel Chion's most fundamental concepts, which provide a theoretical toolkit specifically for analyzing the sound-image relationship in film.

Key Takeaways:

• The Audiovisual Contract: The spectator's unspoken agreement to perceive sound and image as a unified whole, which forms the basis for all cinematic experience.
• Added Value: The expressive and informational meaning created by the fusion of sound and image. This value is reciprocal: sound enriches the image, and the image enriches the sound.
• Synchresis: The spontaneous, psychological process that forges an "irresistible weld" between a sound and a visual event occurring simultaneously, making the artifice of sound design possible.

These concepts move us decisively away from the environmental focus of soundscape studies and into the heart of audiovisual media. They allow us to analyze not just what we hear, but how what we hear changes what we see, and vice versa.

Preview of the Next Lesson:

Now that we have a framework for the sound-image relationship, our next step is to develop a framework for listening itself. In the next lesson, we will continue with Chion to explore his three listening modes: causal, semantic, and reduced. This will allow us to categorize and understand the different ways we process and interpret the sounds within a film's complex sonic texture.