A canal hearing device with a dual acoustic seal system for preventing
feedback while minimizing occlusion effects. The two-part device comprises
a main module and an elongated tubular insert for conducting sound to the
tympanic membrane and sealing within the bony region of the ear canal. The
main module is positioned in the cartilaginous portion of the ear canal.
The tubular insert comprises a sound conduction tube and a cylindrically
hollow primary seal medially positioned in the bony region. The device
also comprises a secondary seal laterally positioned in the cartilaginous
region. The secondary seal, although providing additional acoustic sealing
for the prevention of feedback, is sufficiently vented to provide a path
of least acoustic resistance for occlusion sounds within the ear canal. In
a preferred embodiment, the tubular insert comprises a coiled skeletal
frame to provide high radial flexibility while maintaining sufficient
axial rigidity for comfortable, kink-resistant, and consistent placement
within the ear canal.
