Abstract: An omnidirectional electret condenser microphone element with improved low frequency background ambient acoustical noise rejection is provided. The omnidirectional electret condenser microphone element includes a plurality of passageways in acoustic series that couple at least one acoustic aperture of the microphone element to an acoustic cavity formed within the microphone element. At least one of said plurality of passageways is of a predefined size that is determined to provide the desired response roll-off within a predefined frequency range. In at least one preferred configuration, the roll-off resulting from the plurality of passageways is greater than 2.0 dB between 300 and 100 Hz. In at least one alternate preferred configuration, the roll-off resulting from the plurality of passageways is greater than 3.0 dB between 300 and 100 Hz.
Type:
Grant
Filed:
August 4, 2008
Date of Patent:
January 31, 2012
Assignee:
MWM Mobile Products, LLC
Inventors:
Medford Alan Dyer, Christopher Todd Welsh, Jeffrey Phillip McAteer, Alan Dean Michel, John Charles Baumhauer, Jr.
Abstract: A passive sound pressure level (SPL) limiter is provided that can be used with audio sources of varying drive levels and headsets, earbuds, etc. of varying sensitivity. The SPL limiter includes a control circuit that includes a rectifier and, in most configurations, a step-up transformer. The SPL limiter also includes a limiting circuit that utilizes a transistor to shunt current from the audio source in proportion to a control signal output by the control circuit. The control circuit may further include a low pass filter, for example an RC filter, and one or more fast limit diode paths. The limiting circuit may further include a feedback network to increase the linear behavior of the limiting circuit.
Type:
Application
Filed:
August 13, 2009
Publication date:
February 17, 2011
Applicant:
MWM Mobile Products, LLC
Inventors:
Joshua James Barr, Medford Alan Dyer, Alan Dean Michel, Christopher Todd Welsh
Abstract: An omnidirectional electret condenser microphone element with improved low frequency background ambient acoustical noise rejection is provided. The omnidirectional electret condenser microphone element includes a plurality of passageways in acoustic series that couple at least one acoustic aperture of the microphone element to an acoustic cavity formed within the microphone element. At least one of said plurality of passageways is of a predefined size that is determined to provide the desired response roll-off within a predefined frequency range. In at least one preferred configuration, the roll-off resulting from the plurality of passageways is greater than 2.0 dB between 300 and 100 Hz. In at least one alternate preferred configuration, the roll-off resulting from the plurality of passageways is greater than 3.0 dB between 300 and 100 Hz.
Type:
Application
Filed:
August 4, 2008
Publication date:
February 4, 2010
Applicant:
MWM Mobile Products, LLC
Inventors:
Medford Alan Dyer, Christopher Todd Welsh, Jeffrey Phillip McAteer, Alan Dean Michel, John Charles Baumhauer, JR.