Dynamic human strategies for localizing tones in rooms

Abstract

Reflections and standing waves in a room cause distorted binaural information, making it difficult for listeners to localize ongoing sound sources. Possibly head motion allows a listener to sample a distorted sound field, gaining dynamic information that enables more accurate localization. The present research tries to discover listener strategies for localizing pure tones using a variable acoustics environment. Over the course of 9-s trials, a head tracker recorded head position and orientation while probe microphones in the ear canals recorded the signals and interaural differences. Therefore, the experiment provided complete information. Two model strategies are considered. In the “nulling” strategy, the listener discovers temporally and spatially discrete head pointing directions where the dominant interaural difference is zero. Candidate directions are weighted by head-pointing perseverance in the vicinity of the interaural zero. In the “inferred source” strategy the listener registers temporally and spatially continuous inferred-source candidates based on instantaneous interaural differences and head pointing directions. Each candidate is weighted by the instantaneous ratio of head-angle change to inferred-source change evaluated at the candidate location. Model strategies are evaluated by comparing weighted candidate source locations with listener response locations.