The use of personal hearing protection devices (HPDs) is often recommended to protect workers' hearing from noise-induced damage when no other means of reducing noise levels at the source is effective. The effects of HPDs on speech communication cannot be neglected in spite of their benefit in reducing the risk of hearing loss. While much research has been directed at speech perception, much less is known on how HPDs affect speech production. The tendency of talkers to raise their vocal effort in noise, known as the Lombard effect, is often disrupted by HPDs due to their occlusion effect and the lower noise at the ears as well as the attenuated feedback from one’s own voice. Three main knowledge gaps are addressed in this thesis. The first gap is to characterize speech produced by talkers with or without HPDs under realistic acoustic conditions while immersed in an external noise field. The second gap is to evaluate more comprehensively speech production under protected and unprotected talker and listener ear conditions in different types of fluctuating and continous noises. The third gap is to assess the alterations in the characteristics of speech produced by talkers wearing level-dependent HPDs set at different transmission gain settings and in comparison with passive HPDs. This thesis extends methods used to recover Lombard speech elicited in an external noise field. For this purpose, two noise suppression methods, direct waveform subtraction (DWS) and adaptive noise cancellation (ANC), were found to adequately remove noise from speech recorded for SNRs as low as −10 dB. Moreover, this work contributes new knowledge on the effects of conventional passive HPDs on speech production. When talker wears HPD in noise then speech level were found to decrease by up to 9 dB in continuous noises and by 7 dB in fluctuating noises compared to open ears, while speech levels were found to increase by about 5 dB in all noises when the listener wears HPD. Furthermore, changes in pitch and spectral levels were consistent with changes in speech levels. The effects of level-dependent HPD on speech production, depending on the chosen transmission gain setting, revealed that it led to smaller decrease in talkers’ speech levels in noise compared to conventional passive HPD. These findings indicate that the level-dependent HPDs may impede communication less than conventional passive HPDs, while providing protection against high levels of noise.

Made available in DSpace on 2015-07-22T20:50:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-01-26 / Objetivo: verificar e comparar as crenças e atitudes frente à perda auditiva e proteção auditiva auto-declaradas por funcionários entre duas indústrias do ramo sucroalcooleiro, com e sem participação em um programa de conservação em saúde auditiva.Método: Participaram do estudo 120 funcionários da usina A que receberam o treinamento específico em saúde auditiva e 87 funcionários da usina B, que não receberam o mesmo treinamento. Foi utilizado o questionário “Crenças e atitudes sobre proteção auditiva e perda auditiva”, elaborado por pesquisadores do NIOSH (1996), o qual foi aplicado após o treinamento em saúde auditiva, que é uma das etapas do Programa de Saúde Auditiva - PCA, desenvolvido pela usina A. Para a usina B, o questionário foi aplicado em dias marcados com o setor de engenharia de segurança do trabalho, não seguindo, portanto a seqüência do treinamento em saúde auditiva, uma vez que esta empresa ainda não desenvolve o PCA. A idade média dos funcionários da usina A foi de 31,8 anos e para usina B 30,5 anos. O tempo de exposição médio a ruído dos voluntários da usina A e B foi de 10 anos. A maior parte dos funcionários de ambas as usinas trabalhavam expostos a ruído superior a 85 dBA, com até 10 anos de tempo de exercício. Resultados: Das 10 temáticas avaliadas no questionário destacam-se três: a melhor percepção de susceptibilidade de adquirir uma perda auditiva (p<0,001), melhor percepção de obstáculos de uma ação preventiva quando relacionado ao conforto do uso do protetor auditivo (p=0,022) e melhor percepção da auto-eficácia relacionada ao sucesso frente as ações recomendadas para proteção da saúde auditiva(0,005) observadas na Usina A quando comparadas a usina B. Apenas um funcionário da usina A afirmou não fazer uso de protetor auricular. O escore total das respostas ao questionário da usina A foi maior (p= 0,010) e estatisticamente significantes , em relação aquele da usina B. Conclusão: Através do presente estudo, verificou-se que a aplicação do questionário “Crenças e atitudes sobre a proteção auditiva e perda auditiva”, nos permitiu conhecer a realidade mais próxima dos funcionários quanto ao seu conhecimento sobre a saúde auditiva que demonstrou o cumprimento mínimo das normas regulamentadoras do Ministério do Trabalho. Ao se comparar os resultados entre as usinas com e sem programa de conservação auditiva, foi possível concluir que a usina sucroalcooleira A, que implementou um PCA, desde 2006, apresentou melhor percepção com diferença estatística significante, comparada à usina B em relação às temáticas T1,T4 e T10 referentes à: percepção de susceptibilidade de adquirir uma perda auditiva, percepção de obstáculos para uma ação preventiva:conforto; e auto-eficácia. / the hearing loss and hearing protection for employees between two industries of the sugarcane branch, with and without participation in a program of conservation in hearing health. Methodology: 120 employees had participated of the study in the sugarcane industry A whom had received the specific training in hearing health and 87 employees from the sugarcane industry B, whom they had not received the same training. The questionnaire was used “Beliefs and attitudes on hearing protection and hearing loss”, elaborated for researchers of the NIOSH (1996), which was applied after the training in hearing health, that is one of the stages of the Program of Hearing Health - PCA, developed for the sugarcane industry A. For the sugarcane industry B, the questionnaire was applied in days marked with the sector of engineering in security of the work, not following, therefore, the sequence of the training in hearing health, however, this company not yet develops the PCA. The average age of the employees in the sugarcane industry A was of 31, 8 years and for sugarcane industry B was 30, 5 years. The average of years of study in the sugarcane industries A and B were of 10 years. Most of the employees both the industries had high risk of hearing loss for exposition to the loud noise above 85db, with interval of 0 the 10 years, as working in the same function for the majority of the employees in the two industries. However, an employee of the sugarcane industry A affirmed that He didn´t use any hearing protector. Results: Nevertheless, 10 thematic evaluated in the questionnaire, the best perception of susceptibilities was observed in the sugarcane industry A to acquire a hearing loss (p<0,001), perception of obstacles of an injunction when related to the comfort of the use of the hearing protector (p=0,022) and better perception of the auto-effectiveness related to the success front the actions recommended for protection of the hearing health (0,005), as well as for a total score(p=0,010) when compared sugarcane industry B that does not develop the PCA. Conclusion: Through this study it was found that the questionnaire "Beliefs and attitudes about hearing protection and hearing loss", allowed us to know the reality closer to employees about their hearing health knowledge that has demonstrated compliance with minimum standards regulating the Ministry of Labour. Comparing the results between plants with and without a hearing conservation program, it was concluded that the sugarcane mill, which implemented a PCA, since 2006, had a relation to thematic T1, T4 and T10 regarding: perceived susceptibility of acquiring a hearing loss, perceived barriers to preventive action, comfort, and self-efficacy. / TEDE

Os equipamentos de proteção individual devem ser utilizados após a implantação de medidas administrativas, de medidas de proteção coletiva, alterações de projeto ou em situações de emergência. Podem ser considerados como a última barreira entre um trabalhador e uma condição perigosa. A seleção destes equipamentos deve ser cuidadosa e este trabalho objetivou a criação de um programa de computador para auxiliar os profissionais responsáveis pelo processo de seleção de protetores auditivos, uma posterior comparação entre as saídas do programa com os equipamentos disponibilizados para os trabalhadores das empresas analisadas e uma análise crítica dos documentos obtidos das empresas. Foi efetuada uma revisão bibliográfica das metodologias de seleção de protetores auditivos, criando-se um fluxograma decisório, com pontos de interação com o usuário para a coleta de dados. Foram utilizados programas de prevenção de riscos ambientais de 7 empresas de mineração, identificadas as atividades cujos níveis de ruído se encontravam acima dos limites legais permitidos, determinando-se a necessidade ou não da utilização de protetores auditivos. Os dados foram introduzidos no programa, obtendo-se uma lista de equipamentos adequados para cada atividade selecionada. Compararam-se os equipamentos selecionados pelo programa com os equipamentos oferecidos pelas empresas, identificando-se as vantagens do programa. Observou-se também a baixa qualidade dos documentos emitidos pelas empresas que, em geral, não atenderam aos requisitos mínimos dispostos na legislação. Verificou-se que, quando selecionados corretamente, os equipamentos selecionados pelas empresas estavam contidos na lista de saída do programa, concluindo-se que o programa permitiu maior flexibilidade na escolha dos equipamentos de proteção auditiva, podendo se refletir em vantagens ergonômicas para os trabalhadores e econômicas para as empresas. / Personal protective equipment should only be used after engineering, administrative and work practices or in emergency situations. For this reason, PPE may be considered the last line of defense between workers and a hazardous situation. This work aims to create computer software to assist safety personnel in the PPE selection process, to compare the results produced by this software with the equipment provided by the companies when data from exposures were input and a critical analysis of the documents provided by the companies. A search for the PPE selection methods was conducted, generating a flowchart for hearing protector selection that was implemented in a web site. Data from risk management programs of 7 Brazilian mining companies were used as input to the software once the high risk of noise exposure activities were identified. A list of adequate equipment was then generated by the software and this list was compared to the list of equipments provided by each company. After a critical analysis the software advantages were found to be the higher flexibility in the choice of hearing protectors brought by the much larger list of adequate equipment. Additional advantages include the smaller amount of time spent looking for the correct choice and the ability to provide multiple choices of equipment for workers to choose from, which increases the comfort and thus the compliance to the PPE program. The quality of the documents provided by the companies was found to be low and lacking several requirements of Brazilian Law. The created software was found to be a useful tool, further testing and improvements are needed to increase its usability and to consolidate it as an asset to health and workplace safety professionals.

Every year, twenty-two million workers are exposed to potentially damaging noise at work. Last year, U.S. businesses paid more than $1.5 million in penalties for not protecting workers from noise. (OSHA, 2016). In the United States ten million people have some kind of noise related hearing loss (CDC, 2016) and noise damage to the ear may not be detected until it is great enough to cause hearing impairment. Grounds keeper’s functions consist of a variety of activities that require the use of powered tools such as mowers, riding mowers, leaf blowers, pressure washers, trimmers/edgers and chainsaws. OSHA has stated that “noise is a potential hazard for most jobs that involve abrasive or high-power machinery, impact of rapidly moving parts (product or machinery), or power tools”. (OSHA, 2016) in addition to this, their job is mostly outdoors exposing them to the added noise of traffic, construction and people. The purpose of this research study was to obtain occupational noise exposure data for groundskeepers who use powered equipment to do their job. The groundskeepers who participated in this research study were volunteers and worked in a University campus in the State of Florida. Personal noise dosimeters were used to collect the data in this study. Exposure information was collected over 6 days for 8-hour work shifts during the summer months of the year. Dosimetry was done on a maximum of five groundskeepers per monitoring day, ranging from 1 to 5 employees per day depending on availability. Results of this study indicate that the highest noise exposures occurred on groundskeepers in charge of mowing by means of a riding mower. Results of this study indicate that the highest 8-hr TWA noise exposure for the groundskeepers (GK) 1 and 2 occurred the first day of testing which was a Monday. Using the OSHA PEL measurement method GK1 exposure was 98.5 dBA, GK2 was 97.6 dBA. Using the same measurement method the highest exposure to GK3: 89.2 dBA, occurred on day five of the assessment. For GK4 the highest exposure occurred on the third day of testing with an exposure measurement of 86.1 dBA. GK5 was only assessed one day and his exposure measured at 84.5 dBA. GK6 AND GK7 were evaluated two days and their highest exposures measured at GK6: 89.3 dBA and GK7: 85.7 dBA. Using the OSHA Hearing Conversation Act measurement method, GK1 was exposed to excessive noise levels (>85 dBA as an 8-hr TWA) on five days of the six day assessment period. GK2 was exposed to hazardous noise levels on all four days he was assessed. GK3 and GK4 exceeded the OSHA HCA standard one of the two days they were monitored. GK 5 did not have noise exposure levels above 85 dBA on the day he volunteered for monitoring. GK6 had exposures over 85 dBA on both days he volunteered to be monitored. Finally, GK7 exceeded the 85 dBA limit on one of the two days they volunteered for this study.

Recreational noise exposure has tripled in the last three decades. A major source of this noise is amplified music. Exposure to amplified music can result in similar auditory damage to that caused by other loud noises. Damage to the inner ear leads to elevations of hearing thresholds, characteristically a loss in higher frequencies. An acquired hearing loss due to amplified music can be referred to as a recreational noise-induced hearing loss. Prevention of recreational hearing loss begins with improving awareness about the risk of amplified music. In order to assess the risk perceptions of young people attending music events, a descriptive design involving a quantitative risk-perception survey was conducted at five music events. Dosimetry measurements were performed in order to describe the sound pressure levels. This investigation provided information regarding the influence of demographics on the perception of risk. It was suggested that women, older age groups, and those from a higher socio-economic status (SES) are more likely to identify themselves as more susceptible to auditory-specific symptoms. The demographics of the population that showed greater propensity for risk was males, those aged 18 to 20 years, those in Matric, homemakers and individuals from a lower income group. These individuals may perceive themselves as invulnerable to negative consequences. Furthermore, majority of those who attend music events have never used earplugs; with only a third of them willing to make use of hearing protection if it were stipulated by law. Concern about one’s own hearing and awareness of other auditory symptoms could be associated with greater compliance to hearing protection. In order to promote healthy hearing behaviour among young people, it is crucial to account for differences in risk perceptions. The findings in this investigation are valuable in terms of the development of recreational hearing health risk preventative strategies. Keywords: noise-induced hearing loss, recreational, risk perceptions, gender, age, education, socio-economic status, hearing protection / Dissertation (MCommPath)--University of Pretoria, 2015. / Speech-Language Pathology and Audiology / Unrestricted

Despite the enactment of hearing protection laws and recommended standards over the last four decades, the prevalence of hearing loss among workers has remained unchanged. Limiting the amount of time spend in high noise areas, as well as wearing hearing protection devices, can reduce the effects of noise on hearing loss. Though research has examined the consistency of use of hearing protection devices (HPD) among workers, the importance of fit, and a real-world comparison to the marketed attenuation needed further examination. The goal of this project is to evaluate the effectiveness of HPDs used by agricultural and industrial workers enrolled in a hearing conservation program by comparing personal attenuation rating (PAR) to the manufacturer’s reported noise reduction rating (NRR). The two study groups were selected since workplaces are required to train workers enrolled in an OSHA Hearing Conservation Program on proper insertion techniques, but farmers do not typically receive any training on using hearing protection unless they are employed elsewhere. The effectiveness of the inserted HPDs were quantified via the 3M E-A-RfitTM Dual Ear Validation System, and the results were compared to the NRR provided by the manufacturer. The fit of hearing protection was evaluated for 60 farmers (247 plug pairs) and 76 workers (275 plug pairs), using four models of earplugs (two formable and two non-formable). The results show that although formable ear plugs have higher reported NRRs, a higher percentage of participants achieved PARs greater than or equal to the A-weighted adjusted NRR-7 for the non-formable plugs.

The research described herein was undertaken to determine how masked thresholds changed when individuals wore an active noise reduction (ANR) hearing protection device (HPD), a passive HPD, or no HPD. An ANR earmuff, a passive earmuff, and a user-molded foam earplug were tested in two types of noises (pink and red) at two different noise levels (85 dBA and 100 dBA). The signal used was an industry-standard backup alarm. The experimental design was completely within-subjects. An ascending method of limits was used to obtain 15-20 correct positive responses, which were then averaged to obtain the masked thresholds for each treatment condition. A visual probability monitoring task was incorporated in the experimental design to provide a loading task for the participants. In addition to masked thresholds, comfort and mental workload were assessed. Finally, participants were asked to rank each of the three HPDs with respect to their perceived ability to facilitate hearing the signal in noise. Results indicated that in 85 dBA noise, masked thresholds were lower when hearing protection devices were worn, compared to the unoccluded condition. Additionally, the results indicated that the ANR device provided a significant advantage (lower masked thresholds) over the passive earmuff in the low-frequency biased red noise (across both noise levels) and the 100 dBA noise level (across both noise spectra). However, the ANR earmuff exhibited no significant advantage over the user-molded foam earplug in any of the conditions. Rather, the user-molded foam earplug produced significantly lower masked thresholds at 100 dBA. The results also indicated that there was no difference between the three devices in their perceived ability to facilitate detection of the signal. There was also not a significant difference in comfort ratings between the three HPDs, although there were several complaints about the comfort of the ANR earmuff during the experiment. / Master of Science

A warfighter's situation awareness is vital to their survival and lethality on the battlefield. Situation awareness, achieved through audition, allows the warfighter to quickly and accurately locate the position of fellow warfighters and potential threats. However, hearing loss, acoustic trauma, or the use of hearing protection can diminish this vital ability to locate sounds in the environment accurately. The introduction of electronically modulated hearing protection and enhancement devices (HPED) is an attempt to improve auditory situation awareness for the warfighter. Currently, however, there are no auditory fitness-for-duty measures that allow an warfighter, commander, or medical personnel to assess localization performance in the open-ear or with hearing protection. Such an assessment is important for pre-placement of a warfighter into a hearing critical job and also as a readiness metric prior-to and during a deployment. The ability to measure performance with a hearing protector will also assist warfighters in selecting protection that will afford maximum performance. This study examined a set of auditory fitness for duty (AFFD) test/stimulus combinations designed to quantify horizontal localization performance. Three listening conditions were used throughout the study; they included an open-ear condition as well as in-the- ear HPED and over-the-ear HPED. The Peltor Com-Tac IITM was used as the over-the- ear HPED and the Etymotic EB15 BlastPLGTM was used as the in-the-ear HPED. Stimuli consisted of filtered pink-noise that differed in both duration and frequency. Frequencies ranged from 500-1000 Hz (low) and 3000-6000 Hz (high) and durations included 300 ms (short) and 3 seconds (long). Stimuli were presented at 60 and 70 dB SPL. AFFD measures were specifically designed to measure current performance or to predict performance after training. Measures of current performance include an accuracy test measured in four quadrants (Left-Front, Right-Front, Left-Rear, and Right- Rear) and a front-back confusion test (FBCT). Accuracy within each quadrant was reduced to a mean absolute error, in degrees, for stimuli presented at 30 deg and 60 deg from the medial plane. FBCT consisted of a percent correct for stimuli presented at 0 deg and 180deg. Measures of post-training performance include an inter-aural cues test and a front-back difference test FBDT. The IACT and FBDT required participants to identify if two sequential stimuli were presented from the same or different locations. The IACT was tested in the left-front and right-front quadrants (for stimuli at 30 deg and 60 deg) and the FBCT was tested with stimuli at 0 deg and 180 deg These tests also provided a percent. Results show that the high-frequency long-duration (H-Long) stimuli predicted current localization performance well, for all listening conditions. Other AFFD test/stimulus combinations were also found to predict performance for a given listening condition, but not for all conditions. AFFD measures designed to predict post-training performance did not show any AFFD test/stimuli combinations that worked for all listening conditions. There were some combinations that worked for a given listening condition but not all conditions. A further analysis of the data showed that the limited number and types of HPEDs used may have confounded these results. Passive hearing protectors as well as HPEDs are known to disturb the spectral and temporal auditory cues that allow for accurate localization. While these cues are disturbed they are often still present in the signal heard by the listener. With training/use of a hearing protector, auditory learning may occur that allows these cues to be used again to accurately locate a sound source. Auditory learning was assessed by providing HPED training/use to novice hearing protection users. Pre and post-training testing was performed with the open-ear, in-the-ear HPED, and over-the-ear HPED. Training was provided for only one type of HPED. Results indicate that auditory learning occurred for the training HPED only. There was no crossover of auditory learning to the non-training protector. Other measures of auditory learning included a subjective confidence rating of the HPED and a measure of response time for the localization task. Results showed that confidence increased for the HPED that was used in training. However, no changes in response time were found for any listening condition. Based on the results of this study, it is recommended that AFFD measures continue to be developed for implementation as pre-placement, HPED selection, return-to-duty, and readiness metrics for U.S. military personnel. It is also recommended that objective and subjective measures of hearing protection performance consider the effect of auditory learning. The rating or ranking of HPEDs by novice users of such a device, without adequate training/use to allow for auditory learning, should be weighed carefully. / Ph. D.

Identical experiments were conducted between two acoustical-testing laboratories to determine the inter-laboratory differences of using two different hearing protection device (HPD) fitting procedures for testing the real-ear attenuation at threshold (REAT) of a popular vinyl foam earplug and a multi-sized premolded PVC single-flanged earplug. The first fitting procedure tested in the experiment is included in the revision of the American National Standards Institute (ANSI) standard S12.6-1984 by the ANSI Working Group ANSI S12/WG11, <i>Field Effectiveness and Physical Characteristics of Hearing Protectors</i>. This fitting procedure, “subject fit,” is intended to estimate “...the attenuation obtained in the top 10-20% of today’s industrial and military hearing conservation programs, i.e. the attenuation that should be obtained by an informed and motivated work force” (ANSI S12.6-199X, Draft 1.4, p. 4). The subject-fit procedure employs HPD-naive subjects, minimizes experimenter involvement, enforces subject-selection controls, and requires subjects to fit the HPD with reasonable comfort using only the manufacturer’s fitting instructions. The subject-fit method differs from the second procedure tested in this investigation, experimenter fit, in both procedure and objective. In the ANSI S3.19-1974 “experimenter-fit” method, which is the procedure currently required by the Environmental Protection Agency (EPA) for the testing and labeling of HPDs (EPA, 1990), the experimenter fits the HPD to the subject (comfort is not a consideration) to determine the optimum attenuation of the HPD. The development of the subject-fit protocol was motivated by the large discrepancy between the attenuation achieved in the field and that claimed by manufacturers of HPDs using experimenter fit from ANSI S3.19-1974. Some experts have developed schemes to derate manufacturers’ laboratory data to approximate attenuation typically achieved in the field. In addition to investigating the differences between the two fitting protocols, other factors relevant to the revision of ANSI S12.6-1984 were studied: subject and experimenter gender effects, ear canal size effects, inter-laboratory differences, and the number of replications and subjects needed for REAT tests. Results indicated that the subject-fit method provided statistically significantly less attenuation than the experimenter-fit method. Subject-fit tended to overestimate in-field attenuation, but not by as much as experimenter-fit. No consistent subject-gender effects were found in the analysis. Experimenter gender did not have a significant effect on subject-fit foam-earplug attenuation. The lack of significant trial effects indicated that the goodness of fit did not change for either fitting condition or across trials. Ear canal size and attenuation effects were documented with mixed results. / Master of Science

Hearing protection can mitigate the harmful effects of noise, but for Service Members these devices can also obscure auditory situation awareness cues. Tactical Communication and Protective Systems (TCAPS) can restore critical cues through electronic circuitry with varying effects on localization. Evidenced by past research, sound localization accuracy can improve with training. The investigator hypothesized that training with a broadband stimulus and reducing the number of presentations would result in training transfer. Additionally, training transfer would occur with implementation of more user-engaged training strategies. The purpose of the experiments described in this study was to develop an optimized auditory azimuth-training protocol for use in a field-validated portable training system sensitive to differences among different TCAPS. A series of indoor experiments aimed to shorten and optimize a pre-existing auditory localization training protocol. Sixty-four normal-hearing participants underwent localization training. The goal of training optimization included the following objectives: 1) evaluate the effects of reducing stimulus presentations; 2) evaluate the effects of training with a broadband stimulus (but testing on untrained military-relevant stimuli); and 3) evaluate performance differences according to training strategies. Twenty-four (12 trained and 12 untrained) normal-hearing listeners participated in the field-validation experiment. The experiment evaluated localization training transfer from the indoor portable system to live-fire blanks in field. While training conducted on the portable system was predicted to transfer to the field, differences emerged between an in-the-ear and over-the-ear TCAPS. Three of four untrained stimuli showed evidence of training transfer. Shortening the training protocol also resulted in training transfer, but manipulating training strategies did not. A comparison of changes in localization scores from the indoor pretest to the field posttest demonstrated significant differences among listening conditions. Training improved accuracy and response time for the open ear and one of two TCAPS. Posttest differences between the two TCAPS were not statistically significant. Despite training, localization with TCAPS never matched the open ear. The portable apparatus employed in this study offers a means to evaluate the effects of TCAPS on localization. Equipped with a known effect on localization, TCAPS users can render informed decisions on the benefits or risk associated with certain devices. / Doctor of Philosophy / Hearing protection can mitigate the harmful effects of noise, but for Service Members these devices can obscure auditory situation awareness cues. Certain powered hearing protection can restore critical cues through electronic circuitry with varying effects on localization. Evidenced by past research, sound localization accuracy can improve with training. The investigator hypothesized that training with a broadband stimulus and reducing the number of presentations would result in auditory learning. Additionally, implementing more user-engaged training strategies would demonstrate more auditory learning. The purpose of the experiments described in this study was to develop an optimized auditory azimuth-training protocol for use in a field-validated training system sensitive to differences among active hearing protection. A series of indoor experiments aimed to shorten and optimize a pre-existing auditory localization training protocol. Sixty-four normal-hearing participants underwent localization training. The goal of training optimization included the following objectives: 1) evaluate the effects of reducing stimulus presentations; 2) evaluate the effects of training with a broadband stimulus (but testing on untrained military-relevant stimuli); and 3) evaluate performance differences in localization performance according to training strategies. In the field-validation study, 12 trained and 12 untrained normal-hearing listeners participated. The experiment evaluated localization learning from the indoor portable training system to live-fire blanks in a field. Training conducted on the portable system was predicted to transfer to the field, but differences would emerge between an in-the-ear and an over-the-ear TCAPS. Three of four untrained stimuli showed evidence of localization learning. Shortening the protocol also resulted in localization learning, but manipulating training strategies did not. A comparison of changes in localization scores from the indoor pretest to the field posttest demonstrated significant differences among listening conditions. Training improved performance for the open ear and one of two active hearing protectors. Posttest differences between the two devices were not significant. Despite training, performance with hearing protection never equaled the open ear. The portable apparatus employed in this study offers a means to evaluate the effects of hearing protection on localization. Knowing the effects of hearing protection on localization apprises users of the benefits and/or risk associated with the use of certain devices.