Fast head-related transfer function measurement via reciprocity

• Published in: The Journal of the Acoustical Society of America Vol. 120; no. 4; pp. 2202 - 2215
• Main Authors: Zotkin, Dmitry N., Duraiswami, Ramani, Grassi, Elena, Gumerov, Nail A.
• Format: Journal Article
• Language: English
• Published: Woodbury, NY Acoustical Society of America 01.10.2006; American Institute of Physics
• Subjects: Acoustic Stimulation; Animals; Audition; Auditory Perception - physiology; Biological and medical sciences; Ear - physiology; Fundamental and applied biological sciences. Psychology; Head Movements; Humans; Manikins; Models, Biological; Perception; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Signal Processing, Computer-Assisted; Sound; Sound Localization - physiology; Microphone; Head; Sound source; Modeling; Direct method; Sphere; Hearing; Virtual reality; Reciprocity theorem; Transfer function; Localization; Sound synthesis; Speaker
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.2207578

An efficient method for head-related transfer function (HRTF) measurement is presented. By applying the acoustical principle of reciprocity, one can swap the speaker and the microphone positions in the traditional (direct) HRTF measurement setup, that is, insert a microspeaker into the subject's ear and position several microphones around the subject, enabling simultaneous HRTF acquisition at all microphone positions. The setup used for reciprocal HRTF measurement is described, and the obtained HRTFs are compared with the analytical solution for a sound-hard sphere and with KEMAR manikin HRTF obtained by the direct method. The reciprocally measured sphere HRTF agrees well with the analytical solution. The reciprocally measured and the directly measured KEMAR HRTFs are not exactly identical but agree well in spectrum shape and feature positions. To evaluate if the observed differences are significant, an auditory localization model based on work by J. C. Middlebrooks [ J. Acoust. Soc. Am. 92 , 2607-2624 ( 1992 ) ] was used to predict where a virtual sound source synthesized with the reciprocally measured HRTF would be localized if the directly measured HRTF were used for the localization. It was found that the predicted localization direction generally lies close to the measurement direction, indicating that the HRTFs obtained via the two methods are in good agreement.