Despite the availability of active hearing protection devices (HPDs), noise-proof helmets, and earmuffs, passive in-ear HPDs are still widely used by military personnel in loud work environments and during operations due to their versatility and low economic cost. While these passive devices offer adequate sound pressure attenuation, an undesired effect persists known as the occlusion effect. Currently, two solutions are utilized to reduce the occlusion effect for in-ear passive devices: deep insertion and ventilation. Deep insertion methods result in a difficult insertion and discomfort for wearers, while ventilation methods often experience an unavoidable reduction in pressure attenuation. The dilemma between eliminating the occlusion effect and maintaining a desired level of attenuation and comfort significantly impedes the development of passive in-ear HPDs or earplugs. To address this, Oto-Biomechanics proposes the development of an in-ear hearing protection device made from a Nanoporous Polyurea Aerogel (NPA), a highly customizable, soft, low-density, and compressible material with the potential to reduce the occlusion effect. We believes that an NPA earplug would drastically reduce the experienced occlusion effect and improve the wearerÂ’s overall experience while using in-ear HPDs with our material.
