Effect Of Distance Parameters

George Vlad is a sound design intern at Two Big Ears. This is the continuation of a series of experiments with sound design parameters and audio spatialization. Read the first post on ‘Pitch And Perception’ here.

Continuing my journey through VR audio enhanced by 3Dception, I investigate the effects of two other parameters: minimum distance and rolloff factor. As expected, the effects of these parameters, including pitch, work in tandem and therefore must be considered together to manipulate the audience or the player.

Minimum distance

According to the 3Dception manual, minimum distance is the distance after which the attenuation starts to take effect. At a first glance this would normally affect the perceived distance between the listener and the source object. As you can experience in video #1 below, this assumption is correct.

However, in addition to changing the perceived distance, there is an interesting side effect, especially when the source is visible to the player. At values lower than the default 1, the object appears to be smaller than it really is. As expected, for values larger than 1, the perceived size of the object increases. The rolloff curve seems to not only affect our perception of distance, but also the size of the object.

Rolloff factor

As per the 3Dception manual, the rolloff factor affects the exponential attenuation model. Values greater than 1 will result in a steeper curve while values smaller than 1 will result in a gentler curve. Continue…