This Wearable Electret Microphone "Listens" to Your Neck Skin for Clear Speech in Noisy Environments

Researchers at the Pohang University of Science and Technology (POSTECH) have developed a microphone that can pick up a person's speaking voice even in noisy environments — and can be attached to the skin to work around difficulties communicating while wearing a face mask.

"Auditory sensors have shortcomings with respect to not only personalization with wearability and portability," the research team, led by POSTECH professor Kilwon Cho, Dr. Siyoung Lee, and Hajung Roh, explains in the abstract to its paper, "but also detecting a human voice clearly in a noisy environment or when a mask covers the mouth."

While other solutions to the problem have opted for approaches like attempting to extract the speech using a machine learning model, the POSTECH team targeted the root of the problem: the microphone itself. The team's prototype sensor is an electret-powered hole-patterned polymer diaphragm microphone, which attaches to the user's body — picking up the vibration of the skin on their neck as they speak, rather than the vibrations in the surrounding air caused by ambient noise.

"The sensor operates reliably even in the presence of surrounding noise and when the user is wearing a gas mask," the team found during the microphone's testing. "Therefore, the sensor shows strong potential of a communication tool for disaster response and quarantine activities, and of diagnosis tool for vocal healthcare applications such as cough monitoring and voice dosimetry."

The latter, the team hopes, points to the potential to turn the flexible microphone into a diagnostic device — determining any one of a range of respiratory diseases by measuring the frequency of severity of coughs or the patient's voice-usage patterns without having to expose staff to potential infectious agents.

The team's work has been published under closed-access terms in the journal Advanced Materials.