A Little Bit Of Theory

This is just a little bit of background which will serve as a (very) short introduction to some aspects of sound and in particular how sound can be used to manipulate the audiences attention and emotional state – it may well come in handy at the pub quiz one night too so read it carefully and impress all of your friends :)


Wavelength is the horizontal measurement of the complete cycle of the wave

The average ear span of an adult is approximately 7 inches! – bet you didn’t know that!

So What!


Waves of different lengths interact with the ear span and Low frequency waves are so large that they wrap around our ears and make it much more difficult for us to determine the direction that the sound is coming from. The closer the length of a wave is to our 7 inch earspan (approx. 2KHz) the easier it is for us to tell where it is coming from.

So how can that help us?

This is a prime reason why low frequency sounds are often used to help build ominous atmospheres as it can play on the audiences fear response. When audiences are presented with visual and audio stimuli determined to be dangerous, the body instinctively prepares to either fight or flee. This inability to determine where the noise is coming from can be used as a valuable tool to increase an audiences sense of vulnerability.

Conversely sounds around the 2K mark are good for bringing attention to particular details in a soundscape. i.e  2KHz = 7″ = average adult ear span

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Syncing Sounds to Visual Events

Sound travels at approximately 1130 feet per second through the air and light travels a lot faster so in the real world we see an action or event before we hear it. However the accepted practice in sound editing is to sync the audio much more tightly e.g Thunder and Lightning  for dramatic effect.

Building a picture in the minds eye using sound

A simple example:

Car crashes are potentially very complex to animate however sound can be used equally effectively when combined with greatly simplified visual content. Sound can suggest easily imaginable visual sequences with minimal support from the graphic content.

e.g the screech of tyres off-screen can make us anticipate that a crash is about to happen i.e the sound design serves to trigger the audiences imagination and they mentally fill in the gaps. The car needs only be present for a very short period of time.

A quick cut to the panic on the passengers faces couple with the sound of the general panic and then to a still image of a car with its bonnet up and horn blaring up against a tree – complex breaking glass sounds add dramatic effect to a simple crack in the windscreen. If the sound design is effective audiences will be able to recall visual details from the scene even though it only ever existed as a sound piece.


  • Sound can be used to rapidly progress story lines and manipulate the imagination of the audience members who will all have their own personalised version of events that they can visually identify with.
  •  Sound can save an enormous amount of time in animation projects by allowing the animator to work far more efficiently.
  •  In everyday life we all use sound to determine multiple things so it makes perfect sense that we should be using it to help our visual projects communicate our message more clearly.
  •  A well designed sound track helps to simplify complex visual scenes by working with it to provide extra information and detail.
  • Sound can also suggest events outside the field of vision.
  •  We need to guide an audience and their perceptions using a combination of sound and visual elements. They should be viewed as both part of the same experience and not as disparate elements. We are trying to create one piece of media.