An interactive virtual-environment generator for psychoacoustic research II: Collection of head-related impulse responses and evaluation of auditory localization

This note is concerned with an interactive virtual-environment generator (t he SCATIS-lab), which is currently being used for psychoacoustic experiment ation at our institute. While the architecture and implementation of the sy stem has been the subject of a prior note, issues of psychoacoustic perform ance are dealt with here. Starting with a description of the measurement pr ocedure for individual head-related transfer functions (HRTFs), the interpo lation technique for deriving HRTFs for directions located between the meas ured ones is explained. The psychoacoustic performance of the SCATIS-lab in terms of sound localization is then compared to other systems cited in the literature. Evaluation results with and without head movements show that a uditory localization in SCATIS-lab-generated virtual environments and in re al anechoic environments are very similar. Further, it is confirmed that bo th inversions and localization blur decrease considerably when the head tra cker is switched on. To obtain results that can be directly compared to tho se found in the literature, localization experiments were performed applyin g the GELP pointing technique. Alternative methods were tested as well, i.e . pointing with a finger and pointing with the head. These methods were ide ntified as being better suitable for localization experiments in interactiv e auditory virtual environments.