Alan R. Watson

Pressure gradient electret microphone

A pressure gradient electret microphone provided with a plurality of channels extending between ports located in a ring of plastic material disposed about the periphery of a cylindrical back plate. Each of the channels expanding in horn fashion from the port at the diaphragm chamber to ports in the casing, and the ports in the casing being provided with an electrically conducting shield connected to the electrically conducting casing. In one embodiment of the invention, a line extends from the forward side of the diaphragm, and the line is provided with an aperture adjacent to the diaphragm coupling the diaphragm to the surrounding sound field at frequencies below the critical frequency of the line.

Directional microphone with high frequency selective acoustic lens

A unidirectional dynamic microphone provided with a first sound path to the forward side of the diaphragm and a second sound path to the rear side of the diaphragm, a Helmholtz resonator disposed in the first sound path having a sound entrance, and a diffraction lens mounted ahead of the Helmholtz resonator and partially shadowing the sound entrance to the Helmholtz resonator for the purpose of increasing the high frequency response of the microphone.

Electrostatic microphone with damping to improve omnidirectionality, flatten frequency response, reduce wind noise

An electret microphone in which the condenser unit of the microphone is contained within a cylindrical shell open at one end and mounted coaxially on a larger cylindrical casing at the other, the region surrounding the shell and extending to the casing having a mass of closed cellular plastic foam therein, and the open end of the casing being covered by a layer of open cellular foam plastic, the mass of closed cellular foam plastic and layer of open cellular foam plastic being contained within a wire grill.