Three-dimensional auditory display apparatus and method utilizing enhanced bionic emulation of human binaural sound localization

Abstract From the Canadian patent

An artificial, three dimensional auditory display which artificially imparts localization cues to a multifrequency component, electronic signal which corresponds to a sound source. The cues imparted are a front to back cue in the form of attenuation and boosting of certain frequency components of the signal an elevational cue in the form of severe attenuation of a selected frequency component, i.e. variable notch filtering, an azimuth cue by means of splitting the signal into two signals and delaying one of them by a selected amount which is not greater than .67 milliseconds, an out of head localization cue by introducing delayed signals corresponding to early reflections of the original …