Auditory localization researchers are generally familiar with Interaural Level Difference (ILD), Interaural Phase Difference (IPD), Interaural Time Difference (ITD), and spectral cues. However, these cues are not the only factors that should be considered when assessing the effects head-worn devices have on auditory localization. Additional factors for consideration include conflicting cues, spatial release from masking, hearing loss or functional difference, sound level, sound duration, motion, cross-sensory input, familiarity with the sound, and other top-down effects. Each is briefly presented. Most publications focus on azimuth determination and elevation determination, and very few focus on distance determination. The cues for sound localization in the azimuth and elevation are reviewed, with an emphasis on which cue is dominant in each frequency range. The cues used for distances are also reviewed, with an emphasis on which cue is dominant in each distance range. Wearing a hearing protection device can decrease localization performance by attenuating the sound, blocking the pinnae, and introducing non-linear effects. However, when a device initially disrupts sound localization, by just attenuating the sound, a listener can relearn the altered localization cues. The amount of function that can be relearned and the time it takes vary in the literature.
Derek Schwaller (Wed,) studied this question.