Using an acoustic probe the authors have measured the dependence of the level of sound pressure at the inlet to the external auditory meatus of dogs on the azimuth of the source of a tonal signal. It is shown that with rise in frequency from 0·5 to 40 kHz there is gradual "sharpening" of the characteristics of directivity of reception which increases the interaural differences in the intensity of the sound perceived (ΔI). The rotation of the pinnae from the lateral to the frontal position (one of the components of the orientation reaction to sound) leads at frequencies above 4 kHz to fall in the width of the diagrams of directivity and displacement of their maxima to the midline of the head. As a result, in this region the zone of clear coding of the direction of arrival of the sound in the value ΔI increases. It is assumed that the lateral position of the pinnae is optimal for the detection of a signal and the frontal for tracking the displacement of its source in space.
|Состояние||Опубликовано - 1 дек 1985|
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