The Influence of the Masker on the Localization of the Moving Signal in the Horizontal Plane

Abstract The effect of the masker on the localization of the moving signal was investigated in the free field conditions. The experiments were carried out in an anechoic chamber. Sound signals were presented from loudspeakers located on a semicircular arc in the horizontal plane. Bandpass noise bursts (5–18 kHz) were used to create a signal and a masker. The signal and the mask were uncorrelated stimuli and were created from two independent noise bursts. The stationary masker was always on the right at an angle of 15°. The moving signals traveled to or from the masker along two paths located at two places (–86° to –52° and –52° to –18°). The signal and the masker of 1-s duration each were presented either simultaneously or with a delay of the signal onset relative to the masker onset. The delay varied from 1 to 40 ms and 1200 ms. The subjects evaluated the start and end points of the trajectory of the moving sounds. Localization data for a moving signal under masking conditions were compared with spatial estimates of the same signal when presented in isolation (without a masker). Localization of the start and end points of the signal in masking condition was compared with localization of the moving source alone. Results showed that the masker affected the start and end points of the signal trajectory. The shift depended on the direction of movement. The starting points were always shifted in the direction of motion of the signal. The end points were shifted in the opposite direction.