Towards a head-movement-aware spatial localisation model: Elevation

A multiple-microphone-sphere-based localisation model has been developed that predicts source location by modelling the cues given by head movement. In order to inform improvements to this model, a series of experiments was devised to investigate the impact of head movement cues on the localisation response accuracy of human listeners. It was shown that head movements improve elevation localisation response accuracy for noise sources. When pinna cues are impaired the significance of head movement cues increases. The improved localisation resulting from head movement is due to dynamic cues available during the period of movement, and not to improved static cues available once the head is turned to face the sound source. Head movements improve elevation localisation to a similar degree for band- limited sources with differing centre frequencies (500 Hz, 2 kHz and 6 kHz), which indicates that both dynamic ILDs and dynamic ITDs are used. Head movements do not improve elevation response accuracy for programme items with less than an octave bandwidth. Head movements improve elevation response accuracy to a greater degree for sources further away from the equatorial plane.