sound in 360° Film

From spatial sound to sound space

the right tools for immersive sound.

Sound as an important tool in storytelling

Hearing is one of the most important human senses. It enables us to perceive a spatial image of our surroundings and activities that take place outside our visual field. Psychoacoustic phenomena also provides information about how we interpret situations created by sound; classifying it as beautiful, threatening, glaring, deep, close, above or behind us. There are many possibilities to use sound in 360° films because the scene authenticity or comprehensibility of action motives can be significantly supported by acoustic implementation. In other words: the film story becomes credible and comprehensible when the image and sound environment are a synergistic unit.

Sound in 360°Film 
In cinema, spatial sound has long been the standard. Most films are 5.1 mixed, so one channel is reproduced in the centre front, one to the left and one to the right. The fourth and fifth channels in the back are also divided into left and right. In 360° film, the technical conditions go one step further. With relatively little effort, spatial sound can be recreated accurately in terms of all desired directions and the distance to the camera. By following the technical requirements, implementation is comparatively cheap and involves few risks. The effect of spatial sound can be easily perceived with HMDs and high quality headphones which pushes immersion.

With the advent of 360° films, a new desideratum arose in relation to the spatial staging of sound. New digital technologies make an auditory perception of space possible. Anyone sitting in a cinema with Dolby Athmos will be able to notice - with enthusiasm - how flying objects, for example, glide audibly over one's head, briefly touch down behind the viewer and then fly forward again very close by the user. But what if we are flying in the scenery and another flying object passes underneath us? How can the sound be designed to help the viewer clearly perceive a movement below verses above?

Sound productions can be realised with 360° sound technology. Acoustically, the audience is in the centre of a sphere. The sound event can be placed and perceived within this sphere at any distance. This is possible because the 360° film sound is only reproduced on headphones. Disturbing sound-physical properties in the real environment, such as reflection or masking, can be faded out (absorption in the sense of 'picking up', reflection for 'throwing back' and masking for 'covering up' sound) A 'green field' should be created on which the soundscape conception and design can be approached with few limitations. The following rules apply in 360° film:

• The conception should be done according to the content and the target media.

• The sound should take on the function assigned to it (syntactically, dramaturgically, technically, etc.).

Technical aspects of 360° sound technology 

Spatial Audio: New Possibilities in Audio Object Placement
Spatial (from the Latin spatium = space) stands for spatial sound simulation. In film, the authentic effect of a sound space depends on how much freedom we are given by placing audio objects in a room. An audio object is a sound source which can be rigid or movable.

Rigid audio objects do not change their position over time. These are, for example, narrators (voice-over), non-diegetic music/soundscapes or ambient sounds, as long as the perspective in a scene remains fixed.

Moving audio objects change their position over time, for example, dialogue while the actors are moving, dialogue during a camera movement/perspective change as well as all other sounds that change their position in the scene due to movement or perspective change.

The possibilities for shaping the sound and sound environment increase markedly in 360°film. Since the listener's position in 360°sound is in the middle of a sphere, sound objects can be placed at any point in the coordinate network; addressing all three dimensions of our hearing sense. The location of the sound expands in one dimension. 

The following axes are available for object placement (see illustration below):

• X-axis: front, rear

• Y-axis: left, right

• Z-axis: top, bottom