Subjective comparison of binaural reproduction using measured and individualized head-related transfer functions based on verbal descriptors of perceptual qualities
Master Thesis of Heiser, Ben
This thesis’ aim is to compare perceptual qualities of individually measured, estimated and generic Head-Related Transfer Functions (HRTFs) using dynamic binaural reproduction. Individual HRTFs that were acquired with a HRTF measurement system and through individualization by Principle Component Analysis based on a subject’s anthropometric dimensions of the head and ears and a non-individual HRTF of an artificial head are used for a subjective comparison using a loudspeaker placed in the same location as the virtual source as a real world reference. Five verbal descriptors defining perceptual qualities are used to compare the perception of the HRTFs: Elevation, Front/Back position, Distance, Sound source width and Coloration. Using these descriptors, a listening test with 16 subjects is conducted in which the three HRTFs are compared with a real source as reference. Pulsed pink noise is used as a stimulus and is played from two different directions. Binaural reproduction is done over headphones while the reproduction of the reference is done over a loudspeakers meaning that subjects need to remove the headphones before listening to the reference. Across all descriptors, perception with the individually measured HRTF showed the fewest differences compared with the reference. Perception with the artificial head’s HRTF showed the most differences compared with the reference. Distance to the sound source was perceived differently with all the HRTFs.