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Simulation Near Eardrum(1989)

Ref: "Headphone simulation of free-field listening. I: Stimulus synthesis",

Frederic L. Wightman, Doris J. Kistler, pp. 858-865, J. Accoust. Soc. Am., 85(2), February 1989.

• Goal: Given x1(t), produce x2(t) s.t. y2(t) equals to y1(t)

¡P  
¡P  -x1(t): electrical signal from a loudspeaker
¡P  -x2(t): electrical signal from a earphone
¡P  -y1(t): resultant electrical signal at eardrum from x1(t)
 -y2(t): resultant electrical signal at eardrum from x2(t)

Fourier Transform: Y1 = X1 L F M

 
 -L: Loudspeaker transfer function
 -F: the free-field-to-eardrum transfer function(Head
 Related Transfer Function, HRTF)
 -M: microphone transfer function
 Y2 = X2HM
 -H: headphone-to-eardrum transfer function
Y2 = X2 H M
let Y1 = Y2, 
 X2 = X1 L F/H
 desired filter transfer function T = L F/H.
measurements were made at all elevations except +72 
and + 90 deg, and at all azimuths around the circle in 15-deg steps.
Thus transfer functions were measured from both ears at 144 source positions.
10 subjects were measured.
¡@

Active Localization of Visual Sound(1990)

• Goal:

¡P  
¡P  - to achieve effective localization of virtual sounds that
¡P  would enable an observer to walk quickly and 
¡P  effortlessly to the position of a simulated sound.
 - see fig.1

• approximation

¡P  
 

• head shadow

¡P  
¡P  - crossover frequency 1.8kHz
 - sinusoidally s.t. Left is attenuated 16dB to Right at 90 deg

• Pinnae shadow

¡P  
¡P  - azimuth = 0, minimum
 - azimuth = 180, maximum 3dB