Transcript Psychoacoustics

CHAPTER 12
Sound Localization and
Binaural Hearing
Binaural Hearing: Some Terms
• AZIMUTH-angle from straight ahead in
horizontal plane.
• Minimum Audible Amgle- jnd for azimuth.
(smallest at 0 degrees, largest near 90 and
270 deg.)
Binaural
LOCALIZATION &
LATERALIZATION
LOCALIZATION:
• ability to determine location of a sound
source in the sound field.
LATERALIZATION:
• perceived position of sound within your
head for stimulation under headphones.
Binaural
Binaural
Sound Localization
LOCALIZATION CUES:
• INTERAURAL TIME DIFFERENCE
works best at low freqs: up to 0.65 ms at 90 deg.
• INTERAURAL INTENSITY DIFFERENCE
works best at high freqs: where head shadow
exists.
• PRECEDENCE EFFECT
people can tell which ear was stimulated first.
Binaural
Masking Level Difference (MLD)
Masker and Signal in Each Ear
Test Threshold twice:
> once with identical signals in each ear
> once with 180 degrees out of phase R to L
Binaural
Masking Level Difference (MLD)
(cont’d)
• Signal is easier to detect with the interaural
phase difference
• Shift in threshold is about 12 to 15 dB at low
frequencies.
• Reflects processing in the auditory brainstem)
Binaural