Accession Number : AD0423421
Title : INVESTIGATION OF THE DESIGN AND OPERATION OF SOUND SYSTEMS FOR CIVIL DEFENSE.
Descriptive Note : Final rept.
Corporate Author : BOLT BERANEK AND NEWMAN INC CAMBRIDGE MASS
Report Date : 15 NOV 1963
Pagination or Media Count : 1
Abstract : Outdoor Civil Defense alerting and voice warning systems for urban areas have been traditionally designed using sources of sound mounted high above the buildings. Results have generally not been satisfactory, because of sound attenuation in the atmosphere. As an alternative, the blockby-block coverage system is investigated in this study. In this system directive sound sources are placed in the streets. The results of extensive acoustic and meteorological field tests carried out in city streets show that sound propagation conditions in city streets are favorable. Coverage from elevated sources was found to be suitable only for open areas with low and separated buildings. Design criteria for outdoor Civil Defense warning systems are developed and approximate costs of typical systems estimated. (Author)
Descriptors : (*PUBLIC ADDRESS SYSTEMS, WARNING SYSTEMS), (*CIVIL DEFENSE, SOUND), (*WARNING SYSTEMS, CIVIL DEFENSE), ACOUSTIC PROPERTIES, URBAN AREAS, COSTS, SOUND PITCH, BANDWIDTH, SOUND TRANSMISSION, TEMPERATURE, WIND, ATTENUATION, LOUDSPEAKERS, POWER AMPLIFIERS
Distribution Statement : APPROVED FOR PUBLIC RELEASE