Download or read book The Effect of Helicopter Noise on Communication and Hearing written by Thomas A. Giordano and published by . This book was released on 1973 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: STEM INTELLIGIBILITY ARE SERIOUS ONES. The effort described by this report is aimed at reducing the sound pressure levels at the aviator's ears while maintaining high intelligibility and quality in the communication system. The overall problem is first defined. The noise levels inside all areas of the CH-47 were found to exceed the hearing damage risk criteria set forth by the Surgeon General. Even with hearing protectors, the aviator is limited to the time he may fly without undue risk to his hearing. The electrical characteristics of the communication system were determined. Non-linear frequency responses of the microphone and earcup were detected. These resonances cause emphasis of those frequencies in which the ear is most sensitive. The poor noise cancelling ability of the M-87 microphone at high frequencies cause low signal to noise ratios in the communication system. An intelligibility vs. in-ear dBA level study was run to evaluate the potential success of an 'ideal' perfect noise cancelling microphone and other microphone modifications.
Download or read book The Shock and Vibration Digest written by and published by . This book was released on 1974 with total page 656 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1989 with total page 1134 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evaluation of the Communications Earplug in the H 53 and CH 46 Helicopter Environments written by Ben T. Mozo and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Noise levels inside military helicopters generally exceed noise exposure limits established by DOD Instruction 6055.12, "Hearing conservation" (1991). Noise levels in helicopters with higher load capacities such as the CH-47, CH-46, and H-53 are extremely high and sometimes exceed the helmet's capability to provide adequate hearing protection for crewmembers. Noise compromises communication because of inadequate speech signal to noise ratio at the ear (Mozo, Murphy, and Ribera, 1995; Ribera et al., 1996; Mozo and Murphy, 1997; and Staton, Mozo, and Murphy, 1997). Use of combination protection, earplug in addition to the helmet, does provide the necessary hearing protection, but further compounds the problems associated with communications capability. While active noise reduction (ANR) provides exceptional low frequency hearing protection, it does little or nothing to improve protection for frequencies above 800 hertz. A U.S. Army Aeromedical Research Laboratory (USAARL) report (Mozo and Murphy, 1997) shows ANR does improve speech intelligibility when worn alone, but both hearing protectiOn and speech intelligibility are degraded when worn with ancillary equipment such as spectacles and chemical biological (CB) mask. Aircraft modification, system cost, lateral impact, weight, and others factors should be evaluated carefully when considering the use of ANR in the helicopter environment. The communications earplug (CEP) shown in the figure is a device which incorporates a miniature earphone with foam earplug and can be worn in combination with the aviator's helmet. Calculations show the CEP provides adequate hearing protection for 8 hours duty even in the high noise levels found in the H-53. The device also provides voice communication intelligibility which approaches asymptotic limits near 100 percent in those high noise environments. The system is lightweight, cos.
Download or read book Evaluation of the Communications Earplug in the H 53 and CH 46 Helicopter Environments written by Ben T. Mozo and published by . This book was released on 1997 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of Noise on People written by James David Miller and published by . This book was released on 1971 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Helicopter Noise and Its Effects on Personnel written by Robin Harrison and published by . This book was released on 1976 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Investigation Into the Temporary Auditory Effects of In cabin Helicopter Noise on Flight Students and Flight Instructors at the University of North Dakota written by Janet Lois Turner and published by . This book was released on 1985 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effects of Noise on Man written by Karl D. Kryter and published by . This book was released on 1970 with total page 670 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Noise Spectra and a Listening Task Upon Passenger Annoyance in a Helicopter Interior Noise Environment written by Sherman A. Clevenson and published by . This book was released on 1979 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: A laboratory study was conducted to determine the effects of helicopter interior noise on passenger annoyance. Bothe reverie and listening situations were studied as well as the relative effectiveness of several descriptors (i.e., overall sound pressure level, A-weighted sound pressure level, and speech interference level) for quantifying annoyance response for these situations. The noise stimuli were based upon recordings of the interior noise of the NASA Civil Helicopter Research Aircraft. These noises were presented at levels ranging from approximately 68 to 86 dB(A) with various gear clash tones selectively attenuated to give a range of spectra. The listening tasks required the subjects to listen to and record phonetically balanced words presented within the various noise environments. Results indicate that annoyance during a listening condition is generally higher than annoyance during a reverie condition for corresponding interior noise environments. Attenuation of the planetary gear clash tone results in increases in listening performance but has negligible effect upon annoyance for a given noise level. The noise descriptor most effective for estimating annoyance response under conditions of reverie and listening situations is shown to be the A-weighted sound pressure level. (Author).
Download or read book Effects of Aircraft Noise written by Vincent Mestre and published by Transportation Research Board. This book was released on 2008 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt: "TRB's Airport Cooperative Research Program (ACRP) Synthesis 9: Effects of Aircraft Noise: Research Update on Select Topics includes an annotated bibliography and summary of new research on the effects of aircraft noise. The report is designed to update and complement the U.S. Federal Aviation Administration's 1985 Aviation Noise Effects report"--Publisher's description
Download or read book Should Helicopter Noise be Measured Differently from Other Aircraft Noise written by John A. Molino and published by . This book was released on 1982 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Helicopter Noise on Passenger Annoyance written by Sherman A. Clevenson and published by . This book was released on 1979 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Noise and Military Service written by Institute of Medicine and published by National Academies Press. This book was released on 2006-01-20 with total page 339 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Institute of Medicine carried out a study mandated by Congress and sponsored by the Department of Veterans Affairs to provide an assessment of several issues related to noise-induced hearing loss and tinnitus associated with service in the Armed Forces since World War II. The resulting book, Noise and Military Service: Implications for Hearing Loss and Tinnitus, presents findings on the presence of hazardous noise in military settings, levels of noise exposure necessary to cause hearing loss or tinnitus, risk factors for noise-induced hearing loss and tinnitus, the timing of the effects of noise exposure on hearing, and the adequacy of military hearing conservation programs and audiometric testing. The book stresses the importance of conducting hearing tests (audiograms) at the beginning and end of military service for all military personnel and recommends several steps aimed at improving the military services' prevention of and surveillance for hearing loss and tinnitus. The book also identifies research needs, emphasizing topics specifically related to military service.
Download or read book The Effects of Noise on Man written by Karl D. Kryter and published by Elsevier. This book was released on 2013-09-03 with total page 654 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Effects of Noise on Man covers the techniques for the evaluation of environmental noise in terms of its effects on human. The book provides the fundamental definitions of sound, its measurement, and concepts of the basic functioning, and the attributes of the auditory system. The text also presents along with their experimental basis, procedures for estimating from physical measures of noise its effects on man's auditory system and speech communications. The last part of the book is devoted to man's nonauditory system responses and includes information about the effects of noise on work performance, sleep, feelings of pain, vision, and blood circulation.
Download or read book Helicopter Acoustics Part 2 written by and published by . This book was released on 1978 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technical Information Indexes written by United States. Naval Air Systems Command and published by . This book was released on 1974 with total page 672 pages. Available in PDF, EPUB and Kindle. Book excerpt:
