Signal bandwidth necessary for horizontal sound localization
Daisuke Morikawa, Tatsuya Hirahara · 2010
This paper clarifies how much signal bandwidth is necessary for horizontal sound localization. Horizontal sound localization experiments were conducted with sixteen listeners using white noise, and fourteen listeners using high-pass noise whose cut-off frequency (Fc) was 2, 4, 8, 12, or 16 kHz, or low-pass noise whose Fc was 0.5, 1, 2, 4, or 8 kHz. Four listeners participated in an experiment on band-pass noise whose FcL-FcH was 2-12, 4-12, 2-8, 2-4, 4-8, or 8-12 kHz. It was very difficult to localize sound for high-pass noise whose Fc was high. Sound localization performance was 64% for 12-kHz high-pass noise while it was 27% for 16-kHz high-pass noise. In contrast, sound localization was possible even for 500-Hz low-pass noise. Sound localization performance was 81% for 1-kHz low-pass noise and 67% for that at 500-Hz. It was also difficult to localize sound for narrowband band-pass noise. Sound localization performance was 56% for 2-4-kHz band-pass noise and 67% for that at 8-12-kHz. These results suggest that the interaural time difference, mainly calculated from low-frequency components, the interaural level difference, mainly calculated from high-frequency components, and spectral cues, mainly calculated from middle-frequency (5-10 kHz) components each play roles in sound localization for band-limited noise. We clarified that signal bandwidth from 2 kHz to 12 kHz is necessary to perform good horizontal-sound localization.