Mark A. Ericson
Richard L. McKinley
AL/CFBA, Wright--Patterson AFB, OH 45433-6573
An auditory localization cue synthesizer has been developed that can electronically encode directional information on various auditory signals and present the sounds over headphones. Performance of the synthesizer has been evaluated in several laboratory studies to validate its reproduction of free-field cues and its potential for various applications. Data were collected for localization in noise, binaural intelligibility level difference, and target acquisition experiments. Subjects were able to localize sounds in spectrally similar noise at low (-10 to -20 dB) signal-to-noise ratios. A 3- to 6-dB release from masking was observed in various single talker and competing message experiments. Directional audio information facilitated visual target acquisition under high visual workload conditions. A comparison between these data and free-field localization data indicates that the synthesizer is capable of reproducing the free-field cues necessary to localize sounds over headphones. The technology for generating localization cues over headphones has shown beneficial effects in these applications without additional training by the listeners.