Inter-individual differences of spectral cues in the median plane

Head-related transfer functions (HRTFs) reflect the interaction between human anatomical structures and sound waves, and depend on individuals due to differences in anatomical structures among individuals. This work investigates inter-individual differences of spectral cues encoded in median-plane individual HRTFs using principle component analysis (PCA). First, magnitudes of individual HRTFs from the CIPIC database are decomposed and reduced dimensions by PCA. Then, individual expansion weights of PCA are extracted. Finally, the inter-individual differences in expansion weights are analyzed using standard deviation. Results show that the inter-individual spectral difference in HRTFs decreases with increasing expansion degree of PCA, and the spatial distribution of large inter-individual difference is always at low elevations. When the expansion degree is 1 and 2, the mean of individual expansion weights mainly reflects the inter-elevation difference. The same method is also applied to a combined HRTF database including 295 subjects.