FILM TYPE PHASE DELAY FILTER FOR OMNIDIRECTIONAL CONDENSER MICROPHONE

摘要

PURPOSE: A phase delay filter for an omnidirectional condenser microphone is provided to increase a mass productivity by using film type conventional phase shift filter. CONSTITUTION: A phase delay filter(100) plays only a sound incident from a predetermined direction in an amplified magnitude while reducing the magnitude of the other sound incident from a direction different from the predetermined one. A rear sound inputted from a rear portion of the microphone is attenuated. The phase delay filter for an omnidirectional condenser microphone has a thickness between 50 and 400 m and has a hole diameter between 0.025 and 15 m. The phase delay filter is the one selected from a group consisting of a fluorine, an acryl-resin group, a cellulose group, a polyimide group, a polyester group, a glass fiber and a silica product.