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Many studies have focused on the importance of pinna spectral cues in vertical median plane localisation, and on the ability of the pinna to localise high or low frequency sounds. The purpose of this experiment is to determine the importance of the pinna, and its ability to localise spectrally complex (high) not low frequency sounds. ... The findings suggest that performance in the noise/ pinna normal was significantly better than chance, and that the pure tone/ normal pinna conditions performance was not significantly different. Contrary the third hypothesis, the findings stated that the performance in the noise/ pinna occluded were significantly greater than chance, however this may be due to the methodology of this experiment, as pinna and spectrally complex sounds have been found to be important in sound localisation. ... Horizontal (or azimuthal) sound localisation depends on interaural, or binaural disparity cues, due to the head being in between the ears, creating a source of high acoustic impedance from one ear to the other (Middlebrooks, 1992). ... Due to this cancellation, it is then assumed that spatial cues from other sources are activated, such as the pinna.
The pinna is the “auricle of the ear”, the external, fleshy part of the ear (World Book Dictionary), and its transformations play a major part of the spectral cues that assist in the localisation of sound on the MVP (Batteau, 1967; Butler & Humanski, 1992; Gardner & Gardner, 1973; Middlebrooks & Green, 1991; Searle, Braida, Cuddy& Davis, 1975). ...
Many studies have been conducted testing the use of the pinna in sound localisation. Humanski and Butler (1992), Morimoto (1993) and Gardner & Gardner, (1973), conducted studies to determine the role of the pinna by occluding the pinna and concha, the deepest cavity of the pinna, separately and combined (Gardner & Gardner, 1973). Others mentioned in Pierce, (1901 cited in Gardner & Gardner, 1973) attempted to bind the pinna to the head, partially or fully occlude the pinna or enlarge the effective area of the pinna to examine how the pinna influences sound localisation.
One of the first experimenters to analyse the pinnae specifically as the source of the spatial cues for sound localisation in the medial plane was Batteau (1967). He stated that the pinna may, in the course of reflecting the sound through its convolutions, transform the sound by means of delay paths. This in turn would produce spatial cues allowing location of the source of the sound. This transformation occurred through miniscule time differences created by the pinnae producing elevation dependant spectral changes, and when reaching the tympanic membrane, altering the frequencies’ components.
Approximate Word count = 2045
Approximate Pages = 8.2
(250 words per page double spaced)
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