Auditory localization cue synthesis and human performance

Directional audio technology for headphone applications is discussed. A laboratory demonstration model of a real-time, digital auditory localization cue synthesizer is integrated with a head position tracker, A/D and D/A converters, and a host computer to form a directional audio display (DIRAD). The DIRAD presents sounds over headphones that are perceived to be outside of the listener's head and relatively easy to localize. Possible military applications of directional audio technology include integration with radar warning receivers, voice communication systems, and collision avoidance systems. The auditory localization cue synthesizer board is a modular unit that requires analog and digital interfacing, a host PC with a serial data port, a monaural audio input, a Polhemus digitizing position tracker, and a pair of headphones. Performance experiments demonstrated the ability of humans to localize sounds over headphones. Overall mean magnitude errors of 6.0 degrees were measured in the control condition and 4.8 degrees with the DIRAD. Mean response times of 3.5 s in the control condition and 4.3 s with the DIRAD were measured.<>