Capturing Audio Opportunistically
‘Wild sound’ is a broad term for any audio that is recorded on set or on location independently of the camera. It is ‘wild’ because it is not synchronized to a specific picture take. This practice is a proactive and efficient way for the production sound mixer to gather a library of authentic, location-specific audio assets for the post-production team. It is an acknowledgment that some of the most useful and interesting sounds may occur when the camera isn’t rolling, or are best captured without the constraints of a visual take.
The sound mixer is always listening for opportunities to record valuable wild sound. This could be a planned activity at the end of a scene, or an opportunistic recording of an unexpected event, like a unique bird call or a passing classic car.
Types of Wild Sound
Wild sound encompasses a wide variety of audio elements that are invaluable for sound design and editing:
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Specific Sound Effects (P-FX): These are clean recordings of key props or actions from the film. If a scene features a character using an antique pocket watch, the mixer will record a clean ‘wild’ recording of the watch ticking and being opened and closed. This provides the sound editor with a pristine, authentic effect that perfectly matches the visuals, which is almost always superior to a generic library sound.
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Atmospheres: While a sound designer will often build an atmosphere from multiple library elements, a long, clean recording of the actual location’s general ambiance is an incredibly useful starting point. A 5-minute wild recording of a bustling marketplace or a serene forest provides an authentic sonic foundation that can be sweetened and layered in post-production.
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Group Walla: ‘Walla’ is the industry term for the indistinct murmur of a crowd. After shooting a scene in a restaurant or party, the director might ask the background actors to stay and perform some wild walla. They will be directed to chat quietly amongst themselves about non-specific topics, and the sound mixer will record this chatter. This gives the editor a clean track of crowd noise that can be blended into the scene to make it feel populated and alive, without any specific, distracting words.
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Wild Lines: While often categorized as a ‘wild track’, a wild line is a form of wild sound where an actor re-records a line of dialogue on set, off-camera, immediately after a take. This is done to get a clean version of a line that may have been marred by noise during the take.
The Value of Authenticity
The primary benefit of recording wild sound is authenticity. The specific creak of the hero’s leather jacket, the engine sound of the actual picture vehicle, the unique bird calls of the forest where the movie was shot—these sounds ground the film in its own reality. Relying solely on sound libraries can sometimes lead to a generic feel. By gathering a bespoke collection of wild sounds during production, the sound mixer provides the post-production team with a custom-built palette of sounds that are intrinsically tied to the world of the film.