Abstract
The auditory processes involved in the localization of sounds in rooms are still poorly understood. The present study investigated the auditory system's across-frequency processing of interaural time differences (ITDs) and the impact of the interaural coherence (IC) of the stimuli in ITD discrimination and localization. First, ITD discrimination thresholds were measured as a function of signal frequency, reference ITD, and IC using critical-band wide noises. The resulting data were fitted with a set of analytical functions and ITD weights were derived using concepts from signal detection theory. Inspired by the weighted-image model [Stern, Zeiberg, and Trahiotis. (1988). J. Acoust. Soc. Am. 84, 156-165], the derived ITD weights were then integrated in a simplified localization model using an optimal combination of ITD information across frequency. To verify this model, a series of localization experiments were conducted using broadband noise in which ITD and IC were varied across frequency. The model predictions were in good agreement with the experimental data, supporting the assumption that the auditory system performs a weighted integration of ITD information across frequency to localize a sound source. The results could be valuable for the design of new paradigms to measure localization in more complex acoustic conditions and may provide constraints for future localization models.
Highlights
IntroductionPeople are exposed to sound that travels directly from the source to their ears, and to the sound reflected from surrounding surfaces
In daily reverberant environments, people are exposed to sound that travels directly from the source to their ears, and to the sound reflected from surrounding surfaces
The resulting average interaural time differences (ITDs) thresholds were approximated by a set of analytical functions and localization weights were derived using concepts from signal detection theory
Summary
People are exposed to sound that travels directly from the source to their ears, and to the sound reflected from surrounding surfaces. Sound source localization can be challenged because the reflections carry spatial cues, such as interaural time differences (ITDs) and interaural level differences (ILDs), which do not directly correspond to the true source location. Reverberation in rooms does not affect all ITDs and ILDs carried by the sound to the same degree. ITDs and ILDs at the signal onsets are predominantly driven by the direct sound and are less affected by reverberation than ITDs and ILDs carried by the steady-state portions of the signal. Within the steady-state portions, the direct sound and reflections overlap in time which leads to a decrease of the interaural correlation of the ear signals, relative to an anechoic condition where only the direct sound is present. Electronic mail: jorg.buchholz@ mq.edu.au b) at: Oticon A/S, Kongebakken 9, 2765 Smørum, Denmark
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
