ABSTRACT
Professor Chris Darwin (2005) once wrote, “How often do you hear a single sound by itself? Only when doing psychoacoustic experiments in a sound-proof booth!” (p. 278). Unless you are reading this in a very quiet place, the chances are that you will be able to identify sounds from several sources in the space around you. As I write these words in a study in my house, I can hear the singing of birds in the garden, the rustling of trees in the wind, and (somewhat less idyllically) the whirr of the fan in my laptop computer. Our ears receive a mixture of all the sounds in the environment at a given time: The sound waves simply add together when they meet (Figure 10.1). As you might imagine, in a noisy environment such as a party or a busy street, the result can be very messy indeed! To make sense of all this, the auditory system requires mechanisms that can separate out the sound components that originate from different sound sources and group together the sound components that originate from the same sound source. Bregman (1990) has termed the whole process auditory scene analysis.
