Accession Number : ADA622427


Title :   Level-Dependent Nonlinear Hearing Protector Model in the Auditory Hazard Assessment Algorithm for Humans


Descriptive Note : Final rept. 1 Oct 2013-31 Oct 2014


Corporate Author : ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD HUMAN RESEARCH AND ENGINEERING DIRECTORATE


Personal Author(s) : Fedele, Paul ; Kalb, Joel


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a622427.pdf


Report Date : Apr 2015


Pagination or Media Count : 66


Abstract : US Army Research Laboratory technical report ARL-TR-6748, Using the Auditory Hazard Assessment Algorithm for Humans (AHAAH) With Hearing Protection Software, Release MIL-STD-1474E, includes AHAAH with a Hearing Protector Module (HPM) modeling all hearing protector devices (HPDs) as level-independent linear devices. Listed HPDs include several level-dependent nonlinear (LDNL) earplugs. These are modeled linearly, based on Real Ear Attenuation at Threshold (REAT) measurements in closed and open modes. When analyzing auditory hazards with LDNL HPDs applied as linear devices based on REAT measurements, results are generally overly protective, since REAT measurements do not reflect increased attenuations for higher waveform pressures. Several MIL-STD-1474E Working Group members felt LDNL HPD performance must be accurately described and incorporated into AHAAH cited in the MIL-STD. Consequently, a nonlinear pressure-amplitude-dependent model for performance of LDNL HPDs was created and added to the HPM of version 2.1 of AHAAH (Release MIL-STD-1474E). We describe LDNL modifications to AHAAH s HPM and validate the LDNL HPD model by comparing predicted and measured insertion losses (ILs) and waveforms under the HPD, for increasingly intense waveforms. A LDNL HPM will more accurately predict ILs and waveforms under HPDs and support more accurate auditory hazard assessments for complex impulsive waveforms encountered in real situations.


Descriptors :   *ALGORITHMS , *COMPUTER PROGRAMS , *HEARING , *IMPULSE NOISE , EAR PROTECTORS , HAZARDS , INSERTION LOSS , MODELS , RISK ANALYSIS , WAVEFORMS


Subject Categories : Anatomy and Physiology
      Numerical Mathematics
      Computer Programming and Software
      Radiofrequency Wave Propagation
      Protective Equipment


Distribution Statement : APPROVED FOR PUBLIC RELEASE