Final Thesis

Validation of an ellipsoidal model for the individualization of arbitrary Head-Related Impulse Responses

Key Info

Basic Information

Professorship:
MEDAK
Status:
abgeschlossen
Research Area:
Binauraltechnik

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Master Thesis of Parvizian, Farzaneh

In this thesis different subjective evaluation method for the analytical ellipsoid model of Lins & Bomhardt are evaluated. With this model it is possible to adapt the interaural time difference (ITD) of a given HRTF to an arbitrary subject. Therefore different types for the determination of an ITD from an HRTF are presented. Then two different kinds of listening test are designed for the evaluation. It turns out that the first method doesn’t work well for the evaluation of the model. Here the subject two sounds with different ITDs are presented to the subject. Then the subject was asked which of them are closer to a given direction which is marked in the listening room with a light. Because of the disadvantages of this kind of pointing method it was tested which subjects can hear a difference between the original ITD and the adapted ITD. Thus, for the model the head width was measured by a caliper and in addition the ITD of the subject is determined an HRTF measurement in front of the listening test. For the test itself a 3AFC method was used to compare once the original and the adapted ITD from caliper as well as the original and the adapted ITD from the HRTF. It figured out that most of the subject’s whose head is 1.5cm smaller than the original can distinguish between both ITDs. In addition it can be found that with increasing difference in the head width the performance to distinguish between both increases. The comparison between the ITD from the caliper and the subjects’ HRTF it shows that it is harder to detect the difference between the original ITD and one from the measured HRTF of a subject. In this thesis different subjective evaluation method for the analytical ellipsoid model of Lins & Bomhardt are evaluated. With this model it is possible to adapt the interaural time difference (ITD) of a given HRTF to an arbitrary subject. Therefore different types for the determination of an ITD from an HRTF are presented. Then two different kinds of listening test are designed for the evaluation. It turns out that the first method doesn’t work well for the evaluation of the model. Here the subject two sounds with different ITDs are presented to the subject. Then the subject was asked which of them are closer to a given direction which is marked in the listening room with a light. Because of the disadvantages of this kind of pointing method it was tested which subjects can hear a difference between the original ITD and the adapted ITD. Thus, for the model the head width was measured by a caliper and in addition the ITD of the subject is determined an HRTF measurement in front of the listening test. For the test itself a 3AFC method was used to compare once the original and the adapted ITD from caliper as well as the original and the adapted ITD from the HRTF. It figured out that most of the subject’s whose head is 1.5cm smaller than the original can distinguish between both ITDs. In addition it can be found that with increasing difference in the head width the performance to distinguish between both increases. The comparison between the ITD from the caliper and the subjects’ HRTF it shows that it is harder to detect the difference between the original ITD and one from the measured HRTF of a subject.