Sound Source Localization and the Pitch of Very LowFrequency (200 Hz) Sounds

Project: Research project

Project Details

Description

Sound Source Localization and the Pitch of Very LowFrequency (200 Hz) Sounds Sound Source Localization and the Pitch of Very Low-Frequency (<200 Hz) Sounds Scope of Work. Work to be performed in the Auditory Perception Facility in the Speech and Hearing Science Department at Arizona State University under the direction of Dr. William A. Yost, PhD, Professor of Speech and Hearing Science and Director of the Auditory Perception Facility. Two main experimental projects (Projects 1 and 2) will be undertaken; Project 1 has 2 subprojects (A and B) and Project 2 has 2 subprojects (A and B): Project 1. Human subject tests to elucidate unambiguously the localization limit for frequencies< 200 Hz. Sound source localization experiments to measure sound source localization accuracy for: SubProject 1.A. Measurements using pure tones from 200 Hz to as low in frequency as we can make measurements. a) Pilot work will be done to determine the lowest tonal frequencies that can be produced in the lab without distortion and are audible as tones (purchasing different loudspeakers with better very low-frequency responses than the ones currently in the lab may be necessary). b) A range of tones between 250 Hz and this lowest frequency (a) above) will be chosen for sound source localization accuracy measurements using 12 subjects locating sound sources in the front azimuth hemifield. Work Product: SubProject 1.A will take about 3.5 months and the data will be plots of sound source localization performance measures (accuracy, bias, and reliability) as a function of frequency and loudspeaker location. Measures of subject variability will also be made. Depending on the experimental outcomes, one or more journal papers or meeting presentations may be produced. SubProject 1.B. Since pure-tones do not exist in the real world and there is a significant difference in sound source localization accuracy for tones as opposed to noise, we will also measure sound source localization accuracy for low-pass noise stimuli, with upper-frequency cutoffs of 250 Hz, 150, Hz, 100, Hz, 50 Hz and 25 Hz. We will make sound source localization accuracy measurements using 12 subjects locating sound sources in the front azimuth hemifield. Work Product: SubProject 1.B will take about 2.5 months and the data will be plots of sound source localization performance measures (accuracy, bias, and reliability) as a function of frequency and loudspeaker location. Measures of subject variability will also be made. Comparisons of sound source localization accuracy measures between Parts A and B will also be made. Depending on the experimental outcomes, one or more journal papers or meeting presentations may be produced. Project 2. Pitch of complex sounds with selected spectral regions removed. SubProject 2.A. Measurements of the pitch of different harmonic series of tones and the pitch and pitch strength of iterated ripple noise will be made as a function of removing the fundamental component (lowest spectral component) and other harmonics (spectral regions). 12 subjects will be used and the stimuli will have low fundamental frequencies (low, lowest-frequency component) between 20 Hz and 200 Hz. SubProject 2.B The autocorrelation model previously developed by the P.I. will be applied to the data of Part A to determine its ability to account for the pitch and pitch strengths obtained in the experiments. Comparisons will also be made to measurements made in the literature which usually have involved stimuli with fundamental frequencies greater than 100 Hz. Model modifications will be made if needed. Work Product: Project 2 will take about 4 months and the data will be plots of the matched pitch and measures of pitch strength as a function of the fundamental frequency and harmonic removal. Measures of subject variability will also be made. Fits of the predictions of the autocorrelation model will be provided. Depending on the experimental outcomes, one or more journal papers or meeting presentations may be produced.
StatusFinished
Effective start/end date4/15/1412/31/14

Funding

  • INDUSTRY: Domestic Company: $62,882.00

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