Patent ID: 9591417
Date: 2017-03-07
CPC Classifications: G01H,H04R

Claim:
1. An extremely low frequency acoustic measurement system comprising: an electret microphone comprising a membrane, a backplate, and a backchamber; wherein the backchamber is sealed to allow substantially no air exchange between the backchamber and outside the microphone, and wherein one or more of a tension of the membrane, a structure of the backplate, and a volume of the backchamber is selected to compensate for having substantially no air exchange between the backchamber and outside the microphone; and a windscreen enclosing at least a portion of the microphone, wherein the windscreen material is non-porous and is selected from the group consisting of closed-cell polyurethane foam, balsa wood, and silica tile; wherein a shape, size, and material of the windscreen are selected such that substantially no convected pressure fluctuations reach the enclosed portion of the microphone and such that propagating infrasonic signals pass through the windscreen to the enclosed portion of the microphone with substantially no pressure amplitude reduction.