## 4 Discussion  
The results of the statistical analysis confirm the hypothesis that the use of one's own individual HRTF results in improved accuracy in localizing virtual sound sources in the vertical plane. This is particularly evident in determining the starting angle of the sound stimulus in the vertical plane. As the initial orientation of the participant's head requires them to look directly at the intersection of horizontal and vertical paper strips, the employment of individual HRTF furnished the participant with more precise localization information. Additionally, the data that indicates the determination of sound source movement in the vertical plane (83.56% correctly determined directions of movement for one's own individual HRTF, compared to 55.07% for the HRTF of another person and 44.12% for generic HRTF) shows that using one's own individual HRTF enhances the accuracy of dynamic localization. Consequently, this result indicates that using one's own HRTF can lead to a more realistic perception of the virtual auditory environment and foster a more immersive spatial awareness. The results of the statistical analysis regarding the localization accuracy in the horizontal plane indicate that no statistically significant improvement is obtained by using one's own individual HRTF compared to the HRTF of another person. The use of generic HRTF when determining the horizontal starting angle leads to the poorest localization accuracy, which is significantly lower compared to the other tested HRTFs. The box and whisker plot that indicates the accuracy of determining the horizontal ending angle shows that the use of the generic HRTF has yielded slightly better results than other HRTFs, but the improvement was not statistically significant. A possible reason for this is the higher resolution of the generic HRTF, with 2702 defined directions compared to the 1460 defined directions for the individual HRTFs. To examine this issue (if relevant), future work will consider the same density of direction points for all HRTFs. A possible reason for the lack of improvement in horizontal plane localization by using one's own individual HRTF could be that the primary cues for horizontal sound localization, such as interaural time differences (ITD) and interaural level differences (ILD), are primarily determined by the ear canal and not significantly affected by individual head and pinna morphology [34]. Therefore, for sound source localization in the horizontal plane, generic HRTFs have the potential to be used without a significant loss (if any) in localization accuracy. The results obtained from the experiment that tested the ability to recognize one's own individual HRTF show that the listeners as a group displayed a certain degree of ability to identify their own individual HRTF when their HRTF was grouped with three HRTFs of other people, which goes beyond random chance. In this experiment, the participants were asked only to select the HRTF that they believed to be their own. A more effective approach, to be considered in future work, would be to implement a ranking system whereby all four HRTFs that were used in the experiment are ranked in order of preference. This approach would be particularly useful in situations where participants may struggle to differentiate between their own HRTF and the specific HRTF of another person. Furthermore, an acknowledged limitation of the presented approach is that a reference sound signal could have been used. Although the use of the reference signal could imply more significant results in the presented experiment, there is a reason for not using it in the current setup. Since it would be necessary for the participants to remove their headsets for the reference signal, that could disrupt the calibration of the head tracker attached to the headphones. In future work, adequate use of the reference sound signal could be considered so that it would not influence the head tracker calibration.