Active noise reduction microphone placing
AssigneeBose Corporation
InventorRoman Sapiejewski
Life of this patent
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Abstract
A method and apparatus for increasing phase margin in a feedback circuit of an active noise reduction headphone. The method includes providing an acoustic block comprising an acoustic driver comprising a voice coil mechanically coupled along an attachment line to an acoustic energy radiating diaphragm, the acoustic block further comprising a microphone positioned along a line parallel to an intended direction of vibration of the acoustic diaphragm and intersecting the attachment line, the acoustic block characterized by a magnitude frequency response compensating the magnitude frequency response by a compensation pattern that has a positive slope over at least one spectral range above 10 kHz.
Claims8
Apparatus for an active noise reduction headphone comprising:
- an acoustic driver, comprising
- a diaphragm and a voice coil, for applying mechanical force to the diaphragm along a force application line;
- a microphone with a microphone opening positioned within 2 mm of a line parallel to an intended direction of motion of the diaphragm and intersecting the force application line;
- and
- structure for attenuating frequency response aberrations resulting from resonances of components of the acoustic driver.
Apparatus for an active noise reduction headphone comprising:
- an acoustic driver for an active noise reduction headphone, comprising a highly damped diaphragm and a voice coil attached to the diaphragm along an attachment line;
- and
- a microphone, positioned along a positioning line parallel to an intended direction of motion of the diaphragm and intersecting the attachment line.
A noise reduction headphone, comprising:
- an earphone for being urged against a user's head to enclose a cavity, comprising
- acoustic driver comprising a diaphragm and a voice coil, for applying mechanical force to the diaphragm along a force application line to cause the diaphragm to radiate acoustic energy into the cavity;
- a microphone enclosed by the cavity for transducing acoustic energy in the cavity to a noise signal, positioned within 2 mm of a line parallel to an intended direction of motion of the diaphragm and intersecting the force application line;
- and
- structure for attenuating frequency response aberrations resulting from resonances of components of the acoustic driver.
Active noise reduction apparatus comprising:
- an acoustic driver, comprising
- a diaphragm and a voice coil, for applying mechanical force to the diaphragm along a force application line;
- a microphone with a microphone opening positioned within 2 mm of a line parallel to an intended direction of motion of the diaphragm and intersecting the force application line;
- and
- structure for attenuating frequency response aberrations resulting from resonances of components of the acoustic driver;
- and
- an acoustic block characterized by a first magnitude frequency response;
- a compensator characterized by a second magnitude frequency response to combine the second magnitude frequency response with the first magnitude frequency response to provide a combined magnitude frequency response,
- wherein the second magnitude frequency response is characterized by a pattern that has a positive slope at a frequency interval in the spectral portion above 10 kHz.
Dependencies are inferred from the claim text.