Noise canceling gradient microphone

Abstract From the Canadian patent

An improved Broadside SOG microphone assembly is realized by employing a microphone assembly having at least three ports arranged in a non-colinear fashion with the at least three ports defining and being in a "gradient" plane and with both outer adjacent differential pair of ports aligned in a direction substantially toward a prospective talker's lips. Thus, the inner port(s) is always closer to the prospective talker's lips. Each outer differential pair of ports forms a dipole which yields a high spatial gradient and, hence, higher speech sensitivity since they are pointed substantially toward the prospective talker's lips. Just as important as the prospective, talker's lip position …