00000nam 2200000za 4500 9.821131 CaOODSP 20240219183432 cr ||||||||||| 160714s2003 onc|||||o f000 0 eng d CaOODSP eng eng fre n-cn--- D68-4/077-2003E-PDF Accoustical performance of the Communications Ear Plug (CEP) in combination with the Gentex SPH-5 flight [electronic resource] / by Sharon M. Abel ... [et al.]. [Ottawa] : Defence Research and Development Canada, c2003. viii, 30 p. : figures, graphs, tables. Technical report ; 2003-077 "June 2003." Includes bibliographical references. An experiment was carried out to measure the real-ear attenuation at threshold provided by the Communications Ear Plugs (the CEP) and Gentex SPH-5 flight helmet withcommunications capability, worn alone or in combination. Word recognition in quiet and inHelicopter and Sea King noise was also assessed under the three ear conditions. Like the standard issue Aearo E-A-R® foam ear plugs, the CEP worn in combination with the helmet has the capability of increasing the sound attenuation achieved at low frequencies. The CEP has the added advantage of improving the speech-to-noise ratio of the communications channel. Ten subjects with normal hearing were tested. The results showed that the two devices worn in combination provided significantly greater attenuation than the helmet worn alone, by 6-16 dB over the frequency range tested. The best predictor of outcome at each frequency (0.25-8 kHz) was the addition of 5 dB to the higher of the attenuations realized for the devices worn alone. When the devices were worn in combination the level of speech required to achieve a 60% correct word recognition score decreased by about 18 dB due to a 13-dB increase in the absolute level of the speech reaching the ear in combination with a 5-dB increase in the attenuation of the external noise. gccst Technical reports Assessment methods Conceptual definitions Operational definitions Abel, Sharon M. Defence R&D Canada. Technical report (Defence R&D Canada) 2003-077 (CaOODSP)9.820558 PDF 1.46 MB https://publications.gc.ca/collections/collection_2016/rddc-drdc/D68-4-077-2003-eng.pdf