Generation of the amplitude spectra of the individual head-related transfer functions in the upper median plane based on the anthropometry of the listener’s pinnae

• Published in: Applied Acoustics Vol. 155; pp. 280 - 285
• Main Authors: Iida, Kazuhiro, Shimazaki, Hikaru, Oota, Masato
• Format: Journal Article
• Language: English; Japanese
• Published: Elsevier Ltd 01.12.2019; Elsevier BV
• Subjects: Generation; Head-related transfer function; Individualization; Pinna anthropometry; The median plane; Individualization; Generation; Pinna anthropometry; Head-related transfer function; The median plane
• DOI: 10.1016/j.apacoust.2019.06.007
• ISSN: 0003-682X

In order to address individual differences in head-related transfer functions (HRTFs), individualization of HRTFs has been investigated. The amplitude spectra of individual HRTFs for seven directions in the upper median plane for 27 subjects (54 ears) were estimated from twelve pinna anthropometry and partial regression coefficients, which were obtained by multiple regression analyses. The estimated HRTFs had similar prominent notches and peaks to those for the measured early HRTFs. The spectral distortion and the correlation coefficient between the amplitude spectra of the estimated HRTFs and those of the measured early HRTFs ranged from 3.2 to 4.2 dB and 0.83 to 0.95, respectively. The inter-subject spectral difference was 7.4 dB2. Then, multiple regression analyses were carried out again using 24 subjects (48 ears), who were chosen randomly from the full 27 subjects. The amplitude spectra of three naive subjects (six ears), who were not involved in the multiple regression analysis among 27 subjects, were generated using the pinna anthropometry of the subjects and the partial regression coefficients obtained from 24 subjects. The generated HRTFs had similar prominent notches and peaks to those of the measured early HRTFs, although some of the notches were shallow compared with the measured notches. The spectral distortion and the correlation coefficient ranged from 4.6 to 6.2 dB and from 0.72 to 0.91, respectively. The inter-subject spectral difference was 14.0 dB2. The obtained correlation coefficients suggest the potential for generating an outline of the amplitude spectrum of the HRTFs for an unknown listener from the pinnae anthropometry, although there is a certain absolute difference that needs to be reduced between the amplitude spectrum of the generated HRTFs and the measured early HRTFs.