Accession Number : AD0708816

Title :   THE NOISINESS OF DIFFUSE SOUND FIELDS AT HIGH INTENSITIES.

Descriptive Note : Final rept.,

Corporate Author : WYLE LABS HUNTSVILLE ALA

Personal Author(s) : Ollerhead,J. B.

Report Date : AUG 1969

Pagination or Media Count : 103

Abstract : An experimental study was conducted to establish the relationships between the subjective noisiness, frequency and sound pressure level of random noise in a diffuse acoustic field. The experiments were performed in a fabric enclosure installed within a 100,000 cubic foot reverberant chamber. Twenty-four subjects took part. The growth of noisiness with sound pressure level of an octave band of noise centered at 1000 Hz was determined. The variation of noisiness with frequency was measured at four perceived noise levels between 78 and 104 PNdB. For comparison purposes, one equal noisiness contour was also determined for free field listening conditions in a progressive wave chamber. The results indicated that currently used noisiness growth functions are adequate but that the equal noisiness contours may need some modification at low frequencies. Also the contour shapes vary as sound pressure level increases indicating relatively greater noise sensitivity at both high and low frequencies. (Author)

Descriptors :   (*PSYCHOPHYSICS, *AIRCRAFT NOISE), (*NOISE, MEASUREMENT), STRESS(PHYSIOLOGY), CIVIL AVIATION, AUDITORY PERCEPTION, THRESHOLDS(PHYSIOLOGY), FREQUENCY, INTENSITY, NOISE GENERATORS, TEST FACILITIES, MATHEMATICAL MODELS, DISTORTION, TEST METHODS

Subject Categories : Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE