Binaural Directional Hearing—Impairments and Aids

It is apparent, particularly when we close our eyes, that the auditory system creates a spatial representation of the acoustic environment. We are able to monitor sound sources in all directions, determine the nature and positions of the various sound sources, and focus our attention on sounds in a particular direction. In addition, we can determine certain aspects of the environment itself, such as the size and acoustic “liveness” of the space in which the sounds are generated. Although certain aspects of auditory spatial perception and directional hearing can be achieved when listening with a single ear, it is clear that listening is easier and more effective when listening with two ears. This conclusion is supported by subjective reports as well as by objective experiments on both normal and hearing-impaired listeners (e.g., see Durlach and Colburn, 1978; Durlach et al, 1981; Blauert, 1983; Hausler et al, 1983).