Earmolds and Impressions

Custom shells for power, retention, and comfort

Overview

Earmolds are custom shaped pieces made from an impression of the ear canal and outer ear, used to couple hearing aids to the ear, to provide hearing protection, or to house in ear monitors and earphones. They improve retention, especially in children, and create the acoustic seal needed for high gain hearing aids without feedback. Styles include full shell, half shell, canal, and skeleton designs, trading discretion against retention and sealing. Materials range from soft silicone to hard acrylic. Venting, a small channel through the mold, lets low frequency sound escape and reduces the occlusion effect, the hollow, booming perception of one own voice. Impressions are taken by placing a foam or cotton block deep in the canal to protect the eardrum and then filling the canal with a soft silicone material; digital scanning of the ear is increasingly used. Custom in ear monitors used by performing musicians are made the same way and also provide substantial sound isolation.