Listener orientation and spatial judgments of elevated auditory percepts

Abstract

How do listener head rotations affect auditory perception of elevation? This investigation addresses this in the hopes that perceptual judgments of elevated auditory percepts may be more thoroughly understood in terms of dynamic listening cues engendered by listener head rotations and that this phenomenon can be psychophysically and computationally modeled. Two listening tests were conducted and a psychophysical model was constructed to this end. The frst listening test prompted listeners to detect an elevated auditory event produced by a virtual noise source orbiting the median plane via 24-channel ambisonic spatialization. Head rotations were tracked using computer vision algorithms facilitated by camera tracking. The data were used to construct a dichotomous criteria model using factorial binary logistic regression model. The second auditory test investigated the validity of the historically supported frequency dependence of auditory elevation perception using narrow-band noise for continuous and brief stimuli with fxed and free-head rotation conditions. The data were used to construct a multinomial logistic regression model to predict categorical judgments of above, below, and behind. Finally, in light of the psychophysical data found from the above studies, a functional model of elevation perception for point sources along the cone of confusion was constructed using physiologically-inspired signal processing methods along with top-down processing utilizing principles of memory and orientation. The model is evaluated using white noise bursts for 42 subjects' head-related transfer functions. The investigation concludes with study limitations, possible implications, and speculation on future research trajectories.