Binaural measures of spatial properties of audio reproduced in cars
Tomas Fajersson, Henrik Wikner · KTH Publication Database DiVA (KTH Royal Institute of Technology) · 2008
This master's thesis was carried out at Volvo Car Corporation in Gothenburg, Sweden. The purpose was to find objective measures for the spatial properties of the sound image in the car compartment. Two objective binaural measures, FIACC and perceived frequency response, have been found to describe these spatial properties as perceived by the human auditory system. Due to the decorrelating characteristics of the car compartment, frequencies below 1000Hz were found to be most important when measuring the localization. The measures were implemented in a tuning procedure as a complement to the subjective tuning methods used today. Through the introduction of a phantom source a more symmetrical sound image was achieved, compared to most car audio systems. Furthermore, the phase relationship between the front speakers was found to be of great importance for the perceived center impression. Spaciousness, simulated by the Dolby Pro Logic II decoder, was found to increase with additional rear speakers.