Accession Number : AD0629427

Title :   AURAL DETECTION AND IDENTIFICATION OF THE PRESENCE OF PERSONNEL.

Descriptive Note : Final rept.,

Corporate Author : OHIO STATE UNIV RESEARCH FOUNDATION COLUMBUS

Personal Author(s) : Black,John W.

Report Date : 01 NOV 1958

Pagination or Media Count : 34

Abstract : Procedures, equipment, and environmental factors involved in obtaining 96 recorded acoustic samples of men walking, representative of four distances, six terrains, and four numbers of participants are described. Spectral analyses and analyses of the sound-pressure levels of the recordings were made. The terrains fell into three distinct groupings in terms of over-all level. The four distances (and sizes of parties) were orderly if viewed as three distances (and sizes), the two mid-distances (or mid-sizes) being pooled. The 96 recorded sounds of walking were heard by two trained observers. According to their judgments forest was more noisy than would have been predicted from the physical analysis; swamp was consistent in terms of judgments and physical measures. Attention was directed to the relative importance of frequencies 2000-6000 cps in terms of aural detection. Twenty db of recorded wind scarcely provided a masking sound; the same intensity of recorded rain shifted the detection threshold 5 db. A multiple-choice response form was devised through accumulating frequently occurring error response to the task of identifying the sound that was heard. This form permitted scoring correct identification and the spread of responses. (Author)

Descriptors :   (*PERSONNEL, DETECTION), (*DETECTION, PERSONNEL), (*IDENTIFICATION SYSTEMS, SOUND), MAGNETIC RECORDING SYSTEMS, AUDITORY PERCEPTION, SWAMPS, TREES, ACOUSTICS, TERRAIN, NOISE

Subject Categories : Acoustic Detection and Detectors

Distribution Statement : APPROVED FOR PUBLIC RELEASE