jens blauert, bochum binaural hearing and human sound localization
TRANSCRIPT
Jens Blauert, Bochum
Binaural Hearing and Human Sound Localization
Physics Psychophysics
“sounds” “sensations”
Psychophysics“sensations”
Physics“sounds”
ακούειν (akúın)to hear
Acoustics
acoustic event auditory event
Head-Related Coordinate System
Some Key Words
Effect of Head Movement
Binaural Hearing and Human Sound Localization
- Introductory remarks - Directional hearing in the median sagittal plane - Directional hearing with sounds from lateral directions - Distance perception and inside-the-head locatedness - Summing localization - Auditory precedence and the echo threshold - The effect of interaural decorrelation - Binaural signal detection - Suppression of reverberance and coloration - Summary
Directional hearing in the median sagittal plane
Directional Hearing in the Median Sagittal Plane
Directional Hearing in the Median Plane
directionalbands
boosted bands
1/3 octnoise
Directional Hearing with Sounds from Lateral Directions
Lateralization
ear axis
Generation of ITDs and ILDs
attenuatorsdelay lines
Lateralization Blur for ILDs
Lateralization Due to ILDs
Lateralization Blur for ITDs
ITD-Lateralization Cues
right ear
left ear
Lateralization due to ITDs (broad-band signals)
Distance Perception Inside-the-Head Locatedness
Summing Localization Auditory Precedence
Echoes
Standard Stereo-Listening Arrangement
Summing Localization for Broad-Band Sounds
Ear Signals for Impulsive Sounds in Stereo
Summing Localization with Sideways Loudspeakers
after Plenge & Theile
Auditory Effects with Two Coherent Sound Sources
Summing localization Precedence Effect Echo Threshold
broad-bandsounds
primary auditory event
echo
Precedence Effect, Haas Effect and Backward Inhibition
signal: running speech of 50 syllables/s
delay of the reflection
The Effect of Interaural Decorrelation
Some Further Key Words
Controlling the Degree of Coherence
3 independentnoise generators
Spatial Extent of the Auditory Event as a Function of Interaural Correlation
after Dubrovski & Cherniak, 1966
The Perceptive Phenomena of „Auditory Spaciousness“
Pioneer researches e.g., Kuhl, West, Marshall, Barron, Schroeder, Morimoto
Binaural Signal Detection Suppression of Reverberance
and Coloration
The Binaural Intellegibility–Level Difference, BILDCherry’s Experiment
Binaural Suppression of ReverberanceDanilenko’s Experiment
degree of AM, m
reverberant chamber
reverb
anechoicthre
shol
d of
per
cept
ibili
ty
higher localization accuracy, lower blurbetter source segregation (transparency)
suppression of undesired signals (cocktail-party effect)suppression of coloration and reverberance (better articulation)
>> clearer auditory perspective<<
better sense of envelopmenthigher auditory source width (auditory spaciousness)
>> better spatial impression<<
Advantages of Binaural Hearing
Higher Quality of the „Acoustics“!
More details regarding the topic of this lecture can be found in
Jens Blauert (1997)
Spatial Hearing:The Psychophysics of Human Sound Localization
published by
The MIT Press, Harvard MA, ISBN 0-262-02413-6
TASK A
Young men and women (about 30 years old) have applied to be admitted to a school for airline pilots.
For being accepted, they must have very good spatial-hearing capabilities.
This is necessary, among other reasons, because they have to respond correctly to signals from auditory displays in the cockpit.
Outline a battery of perceptual tests which could be used to evaluate these capabilities.
(a) What would you measure?(b) Which methods would you apply?(c) What equipment would you need?
TASK B
The binaural-hearing capabilities of elderly people (over 65 years) are to be evaluated by means of routine screening tests.
The goal is to assess their abilities to localize sounds in space and to communicate under acoustically adverse conditions.
The information is needed , among other reasons, to decide if hearings aids should be applied to them – and, if yes, which kind of these?
Outline a battery of perceptual tests that could be used to evaluate these capabilities.
(a) What would you measure?(b) Which methods would you apply?(c) What equipment would you need?