ABSTRACT
The ability to localise a sound source is an evolutionary prerequisite for animals’ survival. For example, when hearing the crack of a twig, as a predator approaches, there is simply not time to wait and look around to check where the sound is coming from. In reality we can localise a sound to an accuracy of about five degrees, given the right type of sound. This level of accuracy is less than that for visual spatial acuity, but more than adequate for survival purposes. Only certain types of sounds are inherently localisable and what is crucial is that they contain a large spectrum of frequencies that is broadband noise. Pure tones, simple tone combinations or narrowband noise cannot be localised. There are a myriad of different uses for sound in alarms and in some cases the addition of a localisability component would be superfluous. However, there are other alarms in which the lack of localisability/directionality is potentially highly dangerous.
