Median Plane Localization of Short Noise Bursts in the Presence of Horizontally Spread White Noise Masker

Recent spatial audio techniques involve separating multichannel signals into direct and background parts. However, determining parameters for localizing short sound sources in background sounds remains challenging due to the limited knowledge of spatial hearing resolution. This paper investigates the localization performance when short bursts in the median plane are presented with spectrally similar, horizontally spread broadband noise. Listening tests examined target stimuli in different median plane locations with and without masker noises, using elevation gain, bias, and error rate to evaluate localization performance. The target stimuli comprised aperiodically repeated multiple-burst stimuli with different burst rates and levels and single-burst stimuli with varied duration and levels. The results showed that the burst rate of multiple-burst stimuli had a weak systematic effect on all the criteria for localization performance, regardless of noise. However, extending the duration of single-burst stimuli increased the elevation gain, and the added noise further improved the localization performance. The masker also improved localization performance when the sound level increased, while unmasked stimuli had the opposite effect. The optimal conditions for improving localization performance with background noise found in this study were a signal-to-noise ratio of ≥18 dB.