Learning the cues associated with non-individualised HRTFs John
Worley and Jonas Braasch Binaural and Spatial Hearing Group
Slide 2
Head-Related Transfer Functions
Slide 3
Binaural and Spatial Hearing Group Individual Differences in
HRTFs Highly idiosyncratic. Differences in HRTF magnitude due to
differences in the size and shape of pinnae. Inter-subject
differences in level as much as 28 dB (Wightman & Kistler,
89a).
Slide 4
Binaural and Spatial Hearing Group Using Non-Individualised
HRTFs Binaural cues cue multiple locations. Cones of confusion lead
to reversal errors. Non-individualised HRTFs result in a 3-fold
increase in reversals over individualised HRTFs.
Slide 5
Binaural and Spatial Hearing Group Learning non-individualised
HRTFs Listeners adapt to long-term pinna modifications (Hofman et
al, 98). Scaling non-individualised HRTFs improves localisation
(Middlebrooks, 99). Localisation is unaffected by smoothing HRTFs
(Kulkarni & Colburn, 98). Visual system calibrates auditory
input Early-blind listeners (Zwiers & Van Opstal, 01).
Compressed visual space compresses auditory space (Zwiers,03).
Slide 6
Binaural and Spatial Hearing Group Methodology Headphone-based
azimuth localisation of scrambled noise. HRTFs from prototype
Neumann KU80 (pinna molded from average pinna). 12 possible
locations, surrounding the listener. Instructed to respond to
auditory event. Responses recorded via GELP method (Gilkey et al
1995). Test auditory localisation over time: Day 1 = Auditory alone
Day 1 to 9 = Auditory location cued by visual stimuli Day 10 =
Auditory alone
Slide 7
Binaural and Spatial Hearing Group Methodology - Testing 330
X
Slide 8
Binaural and Spatial Hearing Group Methodology - Training
210
Results Day 1- Testing Responses clustered in the rear
hemisphere.
Slide 13
Results Training Type I (2 listeners) Type - II (3 listeners)
Response bias
Slide 14
Results All Days- Testing Majority of front-to-back reversals.
No reduction in reversals as a function of time.
Slide 15
Results All Days- Testing Type - I Type - II Type I = No
reversal predisposition. Type- II = Majority of front-to-back
reversals. Response bias significantly determines reversal
type
Slide 16
Conclusions Listeners display a response bias. Response bias
determines reversal type. Overall, Non-sig. reduction in reversals
over training period. Why?, Difference between passive -v- dynamic
listening. Individualised head -v- dummy head.
