You are here

Next Generation Passive Hearing Protection


OBJECTIVE: Develop and demonstrate a passive hearing protection that affords true sense of presence for normal sound with directionality. DESCRIPTION: Hearing loss secondary to blast trauma, is now the most common combat injury in Iraq and Afghanistan. The use of passive hearing protection that protects against transient impact noise at the same time allowing ambient sound would enable Marines to continue to hear and respond in combat, thereby enhancing situational awareness while blocking and/or reflecting harmful blast shock waves in the ear canal. Current ear plugs and over the ear muffs block both loud sounds and the sound of normal speech. As a result, they are not worn when needed, or are worn in a manner that permits normal verbal communication but that makes the devices ineffective for hearing protection. This research effort seeks to demonstrate hearing in a modular fashion, while enhancing communication capabilities at short distances, in a small compact form suitable for field use. Solutions should provide adequate fit across the majority of the population (5th percentile 95th percentile), be easy to clean/maintain, be environmentally durable, maximize ability to detect/identify/pinpoint sounds, be lightweight, easily donned/doffed, and be compatible with currently fielded military equipment, to include helmets. The successful solution should meet the following specifications: - Minimal/No electronic components. - Attenuates impact noise at 125 dB, 140 dB, 160 dB and 171 dB by at least 30 dB. - Maintain a Noise Reduction Rate (NRR) of 12 or less. (NRR is a measure of how much noise earplugs block in the 30 decibel to 60 decibel volume range). - Afford both a sense of presence and directionality of the noise source. - Not interfere with headphones or helmets. - Be available in multiple sizes to fit comfortably in the 5th percentile to 95th percentile Marine. - Not be a custom mold design and should be considered a low cost consumable product. - Material should be compatible with long term use. Hearing protection shall target a NRR of 30 dB or greater and accommodate steady-state and impulse type noise. The system shall maintain the ability of the User to detect, identify, and localize sound, be capable of being turned on/off by either hand (as applicable), with a goal of allowing for near-normal hearing in quiet environments. The design shall provide a good fit, be comfortable, and maintain proper seal for the majority of User population (5th percentile 95th percentile), be easy to clean/keep sanitary, be compatible with currently fielded equipment such as helmets, be lightweight, and be durable in an operational environment. Enhanced communication capability shall be provided, effective at short ranges. The system shall be robust and geared toward operation in multiple environmental conditions. The system shall be capable of being used without removal of helmet. PHASE I: Select from the potential approaches to hearing protection currently used, such as non linear and membrane technologies, to identify an alternative approach that will allow significant enhancement in the ability to detect low level ambient sound while being worn. PHASE II: If needed, Improve upon the design concept developed in Phase I and deliver a quantity of refined working prototype systems. The phase II prototype shall demonstrate a means of incorporating hearing protection and communications capability. In depth testing of the system shall be conducted to demonstrate performance with respect to its intended use, and shall verify/expand upon the design characteristics addressed during the Phase I effort. Deliver a report detailing: (1) the design of the device, to include detailed drawings and schematics; (2) the fabrication processes and associated materials/equipment; (3) testing conducted (to include equipment and methodology) along with results demonstrating the degree of effectiveness of the system for its intended purpose; (4) any limitations of the device, such as effective range, length of operation, etc; (5) updated summary of key characteristics, end item cost estimates, and manufacturing considerations, to include any special processes or equipment anticipated for production purposes; (6) produce and deliver ten prototype devices to the Government for the purposes of testing in a relevant environment. The success of performance evaluation and testing results, if favorable, will lead into Phase III applications. All research, development and prototype designs shall be documented with detailed descriptions and specifications of the materials, designs, processes, and performance. PHASE III: Given successful completion of Phase II, a larger quantity of the integrated device shall be manufactured for larger scale testing and demonstration of manufacturability, reliability, and quality assurance. Prior to use in an operational environment, the complete system must, at a minimum, demonstrate a reasonable degree of hearing protection. In addition, this technology can be applied to civilian law enforcement, industrial and recreational users with similar needs for protection. PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: Commercial applications that would benefit from this technology include: protection for police and other security forces while maintaining situational awareness and the ability to communicate with other team members; factory settings in which machinery produces high levels of noise and where communication between operators is essential; competitive sports, such as those involving firearms; hunting and recreational shooting; etc. REFERENCES: 1. DoDI 6055.12,"Hearing Conservation Program (HCP)", Dec 2010 2. OPNAVINST 5100.23G, Navy Safety and Occupational Health Program Manual, Chapter 18"Hearing Conservation and Noise Abatement", Dec 2005 3. OPNAVINST 5100.19E, Navy Safety and Occupational Health (SOH) Program Manual for Forces Afloat, Chapter B4"Hearing Conservation", May 2007 4. ST 4-02.501,"Army Hearing Program", Feb 2008
US Flag An Official Website of the United States Government