A systematic study of binaural reproduction systems through loudspeakers: A multiple stereo-dipole approach

This Ph.D. thesis presents an investigation of the acoustical and psycho-acoustical characteristics of binaural reproduction systems through loudspeakers. The study was mainly focused on the characteristics of closely spaced loudspeakers – known as stereo-dipoles – when placed at different positions, e.g. in front of, above or in the back of the head. The main objective of this study is to set foundations for the design of a binaural reproduction system that is robust to head rotations and reduces front-back confusions.

Different crosstalk cancellation techniques were investigated and their performance with respect to loudspeaker configurations was evaluated. The robustness with respect to head misalignments of the different loudspeaker configurations was assessed throughout objective and subjective experiments. Results showed that maximum robustness with respect to head rotations is obtained when the loudspeakers are placed above the head and that closely spaced loudspeakers are more robust to lateral displacements than wider span angles. Based on the results obtained from those experiments, a binaural reproduction system that uses three stereo-dipoles is proposed: one pair in front, on pair behind and one pair above the listener. Experimental results show that a reduction of front-back confusions is obtained with the proposed system. Yet, coloration differences between loudspeaker pairs result in a degradation of the localization performance.