The microphone proximity effect is a well-documented phenomenon in the world of electroacoustics. The frequency response and directivity pattern of a pressure gradient microphones change with the distance to the sound source. This work looks into the details of this effect, specifically within the context of condenser microphones. We introduce an analytical model to analyze the proximity effect using only a small number of parameters to define the microphones properties. Our study examines theoretical aspects of the proximity effect and performs comparative analysis with near-field measurements. The model deals with the capsule geometry, diffraction in the near-field, and capsule filter topology. The paper discusses the differences in proximity response among condenser microphones with various polar patterns, membrane configurations (double vs. single membrane), and capsule constructions. Capsules with double membrane construction have a milder low-frequency boost in the near-field compared with single membrane design. This property depends on the ratio of membrane compliance and compliance of the volume between two membranes.
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