Loudspeaker sound field emulation in earphones using HRTFs

• Main Authors: Chiu, Elson Louie C., Cullano, Rodel Archie M., Gordiel, Garyl Royce Y., Kung, John Edward B.
• Format: text
• Language: English
• Published: Animo Repository 2012
• Online Access: https://animorepository.dlsu.edu.ph/etd_bachelors/14781
• Institution: De La Salle University

Head Related Transfer Functions (HRTFs) are a summarization of the direction dependent acoustic filtering a free-field sound undergoes due to a person’s head, torso and pinna. Given that an individuals has their own unique anthropometrics, HRTFs vary as a function of source position and shoe large inter-subject variation. In this study, the system uses generalized HRTFs, taken from the IRCAM Listen HRTF Database, in producing an 2out of the head3 experience that is close to the sound fidelity produced by a pair of loudspeakers while maintaining an acceptable sound listener. The subjective results show that there was no audible drop in quality when HRTFs are incorporated to the sound as having a rating of 85 compared with a rating of 95 of the unprocessed sound. The similarity of the HRTF processed music with a pair of loudspeakers is satisfactory with a rating from 3.4 to 4.0 out of 5.0. The Common Acoustical Pole and Zero (CAPZ) Model proposed by Haneda, Y., Makino S., Kaneda, Y. & Kitawa, N. requires far fewer variable parameters to represents HRTFs. Different approximations of the CAPZ model are subjectively evaluated by different listeners. No approximation was singled out as having the best sound quality, but, it was observed that the amount of balance between the poles and zeroes had an audible effect to the listeners. One combination of poles and zeroes that is included in the set of approximations is a 20 Pole – 230 Zeroes approximation and overall it is rated as the worst, compared to the combination of 30 Pole – 50 Zeroes approximately which is rated as the best. The CAPZ approximated HRTF that is produced by the system has a rating of 3.3 to 4.1 out of 5.0 which indicates that is also has a satisfactory 2out of the head3 experience that is audible to the listeners.