An acoustical switch is provided for a directional microphone of a hearing
aid device. The hearing aid device includes a faceplate having a switch
aperture, a front port, and a rear port. The microphone includes a front
inlet in communication with the front port within the face plate and a
front chamber of the microphone. The microphone further includes two rear
inlets in communication with the rear port within the faceplate and a
rear chamber of the microphone. The acoustical switch comprises a switch
actuator having a body portion and a lever portion. The body portion
includes a first closure surface and a second closure surface. The switch
actuator is adapted to be disposed within the switch aperture of the face
plate of the hearing aid device such that the body portion is disposed
adjacent to the inlets of the microphone. The switch actuator s moveable
between a first position wherein the first closure surface of the body
portion is adapted to cover one of the rear inlets of the microphone, and
a second position wherein the second closure surface of the body portion
is adapted to cover the other of the rear inlets of the microphone. The
body portion includes a side surface having an acoustical resistance
associated therewith wherein the acoustical resistance is substantially
greater than an acoustical resistance between either of the ports and its
respective microphone chamber.