Wind immune microphone

An acoustic device, comprising:

• an enclosed housing defining an inner volume and having a front and a back;
• an acoustic port penetrating the front of the housing;
• a support structure attached to the inside of the housing;
• a first sense structure attached to the support structure;
• a second sense structure attached to the inside of the housing, the first and second sense structures defining a gap between the first and second sense structures;
• a front volume defined by the portion of the inner volume between the first sense structure and the front of the housing;
• a back volume defined by the portion of the inner volume between the second sense structure and the back of the housing;
• and
• at least one vent in the support structure, the at least one vent operatively connecting the front volume and the gap, wherein
• the acoustic device has a cutoff frequency above approximately 100 Hz.

An acoustic device, comprising:

• an enclosed housing defining an inner volume and having a front and a back;
• an acoustic port penetrating the front of the housing;
• a support structure attached to the inside of the housing;
• a first and second sense structure attached to the support structure and defining a gap between the first and second sense structures;
• a front volume defined by the portion of the inner volume between the first sense structure and the front of the housing;
• a back volume defined by the portion of the inner volume between the second sense structure and the back of the housing;
• and
• at least one vent in the support structure, the at least one vent operatively connecting the front and back volumes, wherein
• the acoustic device has a cutoff frequency above approximately 100 Hz.

An acoustic device, comprising:

• an enclosed housing defining an inner volume and having a front and a back;
• an acoustic port penetrating the front of the housing;
• a first and second sense structure attached to the inside of the housing and defining a gap between the first and second sense structures;
• a front volume defined by the portion of the inner volume between the first sense structure and the front of the housing;
• a back volume defined by the portion of the inner volume between the second sense structure and the back of the housing;
• and
• at least one vent in the second sense structure operatively connecting the back volume and the gap, wherein the acoustic device has a cutoff frequency above approximately 100 Hz.

A method of forming an acoustic device, comprising the steps of:

• forming an enclosed housing defining an inner volume and having a front and a back;
• forming an acoustic port penetrating the front of the housing;
• attaching a diaphragm having a compliance Cd to the inside of the housing, the diaphragm dividing the inner volume into a front volume and a back volume, the back volume having a compliance Cv;
• forming at least one vent in the diaphragm, the vent having an acoustic resistance Rl;
• and
• setting Cd, Cv, and Rl to non-zero values such that the acoustic device has a cutoff frequency fc of approximately 100 Hertz or greater, with fc defined by the equation
• f
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A method of forming an acoustic device, comprising the steps of:

• forming an enclosed housing defining an inner volume and having a front and a back;
• forming an acoustic port penetrating the front of the housing;
• attaching a support structure to the inside of the housing;
• attaching a diaphragm having a compliance Cd to the support structure, the diaphragm dividing the inner volume into a front volume and a back volume, the back volume having a compliance Cv;
• forming at least one vent connecting the front volume to the back volume, the vent having an acoustic resistance Rl;
• and
• setting Cd, Cv, and Rl to non-zero values such that the acoustic device has a cutoff frequency fc of approximately 100 Hertz or greater, with fc defined by the equation
• f
• c
• ≈
• 1
• 2
• 
• π
• 
• 
• R
• l
• 
• (
• C
• d
• +
• C
• v
• )
• .