The impact of phase on auditory situational awareness

Abstract

A person’s situational awareness is the ability to understand and correctly interpret the world as it exists around them. One component of auditory situational awareness is sound localization, or the ability to identify where a sound is in space relative to the listener. Different aural cues contribute to a listener’s sound localization: the difference in the time it takes for a sound to reach one ear compared to the other (interaural time difference, or ITD) and the difference in the level of the sound at each ear (interaural intensity difference, or IID). The relative contribution of these interaural differences changes with frequency regime, with ITD/IPD being more dominant at low frequencies and IID being more dominant at high frequencies. These cues, as well as a spectral coloration dependent upon the shape of the listener’s pinna and concha bowl, contribute to what is called the head-related transfer function (HRTF). This study examines the impact of a phase inversion in one ear on a person’s auditory situational awareness. Testing was conducted in accordance with ASA/ANSI S3.71-2019, Method 3 to measure the impact on response time, using full spectrum stimuli as well as band-limited stimuli to focus testing on each aural cue.