Re: front to rear reversals

[John Middlebrooks <jmidd@xxxxxxxxxxxxxxxxxxxxxxxx>]

We have found that the characteristics of front/back confusions in
virtual listening are systematically related to the HRTFs of the listener
and of the HRTFs through which he or she listens.  The individual
differences in HRTFs tend to correlate with the sizes of listeners' heads
and external ears, so it is convenient to refer to "large" and "small"
listeners.  When small listeners use HRTFs from larger subjects, they
tend to localize low frontal targets to the rear and (somewhat less
consistently) high rear targets to the front.  When large listeners use
HRTFS from smaller listeners, front/back confusions are less
common.  The most common error is that low targets are localized
upward.  For instance, as a large listener myself, when I listen through
generic HRTFs I have no trouble hearing frontal targets as in the front,
but I never hear good realizations of low targets .

The work on individual differences in transfer functions is in JASA
106:1480-1492 (1999), and the corresponding psychophysical work is
in JASA 106:1493-1510 (1999).

John C. Middlebrooks
University of Michigan


Date sent:              Wed, 19 Jan 2000 11:36:10 +0900
Send reply to:          William L Martens <wlm@U-AIZU.AC.JP>
From:                   William L Martens <wlm@U-AIZU.AC.JP>
Subject:                Re: front to rear reversals
To:                     AUDITORY@LISTS.MCGILL.CA

Pierre Divenyi wrote:

> I think I am not the only one to disagree with your phenomenological
> observations [about front to rear reversals].

Another important point to note is the existence of individual differences
in response bias.  Typically, about 70% of listeners tend to report that
frontal sources arrive from the rear, while the other 30% tend to report that
rear sources arrive from the front.  See for example, Begault & Wenzel (1991)
Headphone localization of speech stimuli (Proceedings of the Human Factors
Society 35th Annual Meeting, 82-86).

--
William L. Martens, Ph.D.             Associate Professor
Multimedia Systems Lab                URL: http://www.u-aizu.ac.jp/~wlm
University of Aizu                    TEL: [+81](242)37-2791
Aizu-Wakamatsu  965-8580, Japan       FAX: [+81](242)37-2731
_________________________________
Dr. John C. Middlebrooks
Kresge Hearing Research Institute
University of Michigan
1301 E. Ann St.
Ann Arbor, MI 48109-0506
voice: 734-763-7965
FAX: 734-764-0014
jmidd@umich.edu