The absolute difference limen of directional perception in the median plane under conditions of both, natural hearing and hearing with artificial-head-system

An observer with unmovable head and under free-field conditions receives identical signals at both ears, when sound is coming from directions of the median plane. The ability of directional differentiation is then primarily determined by the directional characteristics of the outer ear and is dependent on the spectrum of the sound. Under these external conditions, the following measurements were carried out. At first the absolute difference limen of directional perception were measured with sound coming from before and behind as a function of the spectrum of the stimulus.