An active control strategy to reduce acoustic occlusion in in-ear devices

Occlusion effects occur when the ear canal is sealed with an ear tip, often resulting in discomfort from unnatural low-frequency amplification of ambient and body-conducted sounds. Reducing acoustic occlusion is a significant challenge in hearing aids and other in-ear audio devices. This study proposes an active feedback control method to design a controller to mitigate occlusion effects by suppressing low-frequency gain in the occluded ear canal. A custom hearing aid is fabricated by integrating an electret microphone and a balanced armature speaker into a memory foam ear tip, along with the designed feedback controller. The custom hearing aid is tested on a GRAS ear and cheek simulator, and occlusion effects are compared for fully open, partly open, and fully occluded ears with a designed feedback controller. The methodology discussed in this study for occlusion reduction could have implications for improving user comfort in hearing aids and in-ear audio devices.