NOISE ATTENUATION CHARACTERISTICS OF AN OVERTHE-EAR TYPE PERSONNEL NOISE PROTECTIVEDEVICE.
NAVAL SCHOOL OF AVIATION MEDICINE PENSACOLA FLA
Pagination or Media Count:
The attenuation values obtained from the artificial earmanikin head indicate generally, although not consistently, greater attenuation for the RCA-X1 over previously obtained values on the V-51R up to 2000 cps. Above this frequency more attenuation was found for the V-51R. However, for the continuous aircraft type noises the V-51R yielded increased attenuation values. 1 The relative attenuation values for pulsed pure tone threshold shifts were greater for the V-51R at 125 and 250 cps than for the RCA-X1 but were not as great for the frequencies above 250 cps, with the exeption of 8000 cps. 2 For wide-band and octave-bands of noise the relative attenuation values for the V-51R were greater than for the RCA-X1 at two octave bands, 75-150 and 150-300. However, the results were reversed for the other seven noise bands. 3 The Spondee word threshold shift data show increased attenuation for the RCA-X1 over the V-51R by some nine db. Author