Perforated Concave Earplug (pCEP): A Proof-of-Concept Earplug to Improve Sound Localization without Compromising Noise Attenuation

Nir Fink, Rachel Levitas, Arik Eisenkraft, Linn Wagnert-Avraham, S. David Gertz, Leah Fostick

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Combat soldiers are currently faced with using a hearing-protection device (HPD) at the cost of adequately detecting critical signals impacting mission success. The current study tested the performance of the Perforated-Concave-Earplug (pCEP), a proof-of-concept passive HPD consisting of a concave bowl-like rigid structure attached to a commercial roll-down earplug, designed to improve sound localization with minimal compromising of noise attenuation. Primarily intended for combat/military training settings, our aim was an evaluation of localization of relevant sound sources (single/multiple gunfire, continuous noise, spoken word) compared to 3M™-Combat-Arms™4.1 earplugs in open-mode and 3M™-E-A-R™-Classic™ earplugs. Ninety normal-hearing participants, aged 20–35 years, were asked to localize stimuli delivered from monitors evenly distributed around them in no-HPD and with-HPD conditions. The results showed (1) localization abilities worsened using HPDs; (2) the spoken word was localized less accurately than other stimuli; (3) mean root mean square errors (RMSEs) were largest for stimuli emanating from rear monitors; and (4) localization abilities corresponded to HPD attenuation levels (largest attenuation and mean RMSE: 3M™-E-A-R™-Classic™; smallest attenuation and mean RMSE: 3M™-Combat-Arms™4.1; pCEP was mid-range on both). These findings suggest that the pCEP may benefit in military settings by providing improved sound localization relative to 3M™ E-A-R™-Classic™ and higher attenuation relative to 3M™-Combat Arms™-4.1, recommending its use in noisy environments.

Original languageEnglish
Article number7410
Issue number17
StatePublished - 25 Aug 2023
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2023 by the authors.


This research was funded by the Israel Defense Forces (IDF) Medical Corps and Directorate of Defense Research and Development, Israeli Ministry of Defense (IMOD DDR&D) grants #4440697173 and #4440796070; The Stuart Roden Family Research Fund, London, UK; The Alexander Grass Family Research Fund; The Dr. Bruce and Baila Waldholtz Research Fund, and The Dr. Martin and Grace Rosman Research Fund, Faculty of Medicine, The Hebrew University of Jerusalem, Israel.

FundersFunder number
Alexander Grass Family Research Fund
Baila Waldholtz Research Fund
IMOD DDR&D4440796070, 4440697173
Israel Defense Forces
Hebrew University of Jerusalem
Ministry of Defense


    • hearing protection devices
    • military noise
    • perforated concave earplugs (pCEP)
    • sound localization


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