The influence of timbre and loudness on the localisation of sounds

Abstract

In analysing the factors determining our localisation of sounds, it will be found convenient to distinguish “laterality" from “incidence.” By the laterality of a sound I mean its apparent position in relation to the median vertical front-to-back, or “sagittal,” plane; thus, a sound may give the impression of rightward or leftward laterality, or it may appear to have zero laterality— that is to say, its position may seem to be in the median plane. By the incidence of a sound I means its apparent position in relation to the horizontal “interaural” or “coronal” line, thus, a sound may give the impression of more or less upward, downward, forward, or backward incidence, or it may appear to be directly sideward, neither above nor below, neither in front of nor behind, the interaural line—when the incidence is of zero value. I consider it important to distinguish at the outset these two elements in localisation, since they are dependent on very different factors. In normal subjects, that is to say, in persons who have normal binaural hearing, the one certain and obvious determinant of laterality consists in binaural differences of intensity. A sound is localised on the side of that ear which receives the stronger stimulus; it is localised in the middle line, midway between the two ears, when they are equally stimulated by the sound.