Dissertations, Theses, and Capstone Projects

Date of Degree

1999

Document Type

Dissertation

Degree Name

Ph.D.

Program

Speech-Language-Hearing Sciences

Advisor

Harry Levitt

Committee Members

Arthur Boothroyd

Stanley Gelfand

Arlene C. Neuman

Subject Categories

Speech and Hearing Science

Abstract

Brief bursts of third-octave bands of noise (center frequencies at 0.5, 1.0, 2.0 and 4.0 kHz) and band pass noises with different degrees of low-frequency content (0.5 to 4.0 kHz, 1.0 to 4.0 kHz and 2.0 to 4.0 kHz) were recorded binaurally from 17 different horizontal locations (90 degrees on the left to 90 degrees on the right in 11.25 degree steps) one meter from the ears of an anthropomorphic mannequin (KEMAR) in an anechoic room and a reverberant room. The recorded sounds were processed by attenuating or removing interaural intensity differences and presented to five normally hearing subjects through insert transducers (ER-3A) in a sound-source identification task. The localization accuracy of the subjects for unprocessed signals was similar to that reported in the literature for free-field listening. Auditory localization performance was not significantly degraded by reducing interaural intensity difference cues to 50% of their original value in dB. However, attenuating interaural intensity differences by 100% degraded localization performance by introducing a bias toward the center. The effect was frequency dependent, with no effect for a 0.5 kHz third octave band. Some asymmetries in localization performance were observed. Localization accuracy was similar for signals recorded in a reverberant room as for those recorded in an anechoic room.

Comments

Digital reproduction from the UMI microform.

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