Sound localization

ruprik at ruprik at
Sat Mar 1 01:44:20 EST 1997

On Fri, 28 Feb 1997 19:32:26 +0000, Richard Tuck
<rtuck at> wrote:

>In article <Pine.SOL.3.91.970226160918.11876A-100000 at>,
>"Wei C. Lin" <wlin2 at> writes
>>       I am studying the machinism of sound localization, which is 
>>thought to be accomplished by using the interaural temporal difference (ITD)
>>and interaural level difference (ILD). ITD is thought to be achieved by 
>>neuronal delay line, and will divide azimuth into several partitions.
>>       Does someone hear of any theory which accounts how the ILD is 
>>used along with ITD to divide the auditory space, especially how ILD is 
>>used to estimate the distance of sound source?
>There is another very important source of localisation cues.  This is
>the change in the frequency response between ears caused by the head and
>torso and, at higher frequencies by the pinna.  Without this mechanism
>we would not be able to differentiate between front to back and up or
>I cannot point you in the direction of any literature on the subject but
>it should be reasonably easy to find with online searching.

Head-related transfer functions (or HRTFs) are used to describe the
direction-specific filtering of sound that includes both azimuth and
elevation. They are currently being used to create vitrual acoustic
environments in the 3-D sound devices over headpones. Fred Wightman at
the U of Wisconsin has done considerable research on this. Starkey's
upcoming digital aid, developed at the House Ear Institute, is suppose
to reintroduce the user's 0-degree HRTF in both magnitude and phase.



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