Abstract
Psychoacoustic experiments were conducted to investigate absolute cues for auditory distance in an anechoic room. The presence of absolute cues allows a listener to judge the distance of a sound image with little or no prior experience regarding stimuli or environment. Therefore, the first presentations of the stimuli to the listeners were analyzed. In the first experiment, listeners were divided into three groups based on the distance from a frontal loudspeaker (0.5 m, 1 m, or 4 m) and each group was also divided into four subgroups based on the type of stimulus used in the first presentation. No significant difference was found in the loudspeaker distance or in the type of stimulus by the analysis excluding non-frontal perceptions. The second experiment, in which the loudspeaker was situated at 60 degrees azimuth, demonstrated that the perceived distances of the first presentation were significantly different between the loudspeaker distance of 0.5 m and the loudspeaker distances of 1 m and 4 m. These results imply that the strength of absolute cues in the lateral direction is stronger compared to the frontal direction. Considering the results of measurements on distance-dependent head-related transfer functions reported in previous studies, interaural level differences seem to provide an absolute cue in the lateral direction of 0.5 m.
