Microphone with frequency pre-emphasis
First Claim
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1. A frequency-compensated hearing aid microphone assembly for providing from incoming ambient sound a frequency-varying differential actuating pressure to a transducer-operating diaphragm comprising:
- a housing having a main chamber therein;
a compliant first diaphragm disposed to divide the interior of said main chamber into a first chamber on a first side of said first diaphragm and a second chamber on a second side of said first diaphragm opposite said first side;
transducing means coupled to said first diaphragm for producing an electrical signal responsive to movement of said first diaphragm;
a compliant second diaphragm disposed to divide said first chamber into a transfer chamber and an excitation chamber and disposed in a generally confronting parallel relationship to said first diaphragm;
input port means configured to deliver incoming ambient sound to said excitation chamber at a peripheral region joining said diaphragms to confine entering sound to pass between said diaphragms and parallel thereto, so that inertance presented to sound passing across said diaphragms and the compliance of said first diaphragm form an acoustical distributed line to cause sound intensity transferred to said transfer chamber to vary with frequency; and
bypass port means for transferring to said second chamber sound delivered to said transfer chamber through said second diaphragm to provide a sound intensity against said second side of said first diaphragm which varies with frequency.
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Abstract
A stepped frequency microphone particularly adapted to a hearing aid application provides a stepped frequency response characteristic relative to frequency, and has a low-pass sonic attenuator for providing to the undriven side of the microphone diaphragm a sonic counterpressure which at low frequencies substantially cancels ambient sound pressure delivered to the drive side of the diaphragm, the attenuator reducing this counterpressure at elevated frequencies to provide accentuated high frequency response.
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Citations
8 Claims
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1. A frequency-compensated hearing aid microphone assembly for providing from incoming ambient sound a frequency-varying differential actuating pressure to a transducer-operating diaphragm comprising:
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a housing having a main chamber therein; a compliant first diaphragm disposed to divide the interior of said main chamber into a first chamber on a first side of said first diaphragm and a second chamber on a second side of said first diaphragm opposite said first side; transducing means coupled to said first diaphragm for producing an electrical signal responsive to movement of said first diaphragm; a compliant second diaphragm disposed to divide said first chamber into a transfer chamber and an excitation chamber and disposed in a generally confronting parallel relationship to said first diaphragm; input port means configured to deliver incoming ambient sound to said excitation chamber at a peripheral region joining said diaphragms to confine entering sound to pass between said diaphragms and parallel thereto, so that inertance presented to sound passing across said diaphragms and the compliance of said first diaphragm form an acoustical distributed line to cause sound intensity transferred to said transfer chamber to vary with frequency; and bypass port means for transferring to said second chamber sound delivered to said transfer chamber through said second diaphragm to provide a sound intensity against said second side of said first diaphragm which varies with frequency. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification