Abstract: This application relates to the technical field of speakers and discloses a speaker assembly. The sound-raising assembly includes a first housing, the first housing forms a cavity. The sound assembly includes a cavity, a diaphragm and an armature member, a perimeter of the diaphragm is connected to an inner wall of the cavity, and a side of the diaphragm is provided with a voice coil, the voice coil for driving the vibration of the diaphragm. The armature member is set relative to the cavity and is located on the side of the diaphragm where the voice coil is set. The present application could improve the sound quality of the speaker.

Abstract: A compact multi-element microphone has two rings of directional sensors. Using simple analog electronics, it delivers first-order outputs with low noise, wide bandwidth and tight transient response. The double-ring structure provides exceptionally high directional fidelity in the horizontal plane, while also keeping out-of-plane behaviour under control. This enables faithful capture of ambience, reflections and reverberation. A non-radial capsule arrangement moderates cavity resonances and reduces shading. Combined with digital electronics, the array can efficiently provide second-order and higher-order horizontal directivities that maintain their performance over a wider frequency range than with prior solutions. Outputs can be mono, two-channel stereo and multichannel surround sound. Applications include 360-degree immersive audio, with-height concert hall recording, and advanced voice capture using electronic steering of beams and nulls.

Abstract: A microphone with a combined packaging structure includes: a substrate, a first cover being provided on top of the substrate, the substrate, together with the first cover, forms a first accommodating cavity, an acoustic sensor being provided inside the first accommodating cavity, and an acoustic through-hole being formed in the first accommodating cavity. A second cover is provided on a back face of the substrate, the second cover, together with the substrate, forms a second accommodating cavity, and a proximity sensor is arranged inside the second accommodating cavity. By adopting the above-mentioned technical solutions, the present invention has the beneficial effects that two accommodating cavities are respectively provided on the top and bottom of the substrate in the microphone according to the present invention, for receiving components of a MEMS microphone and the components of a proximity sensor respectively.

Abstract: A microphone, comprising at least two electrodes, spaced apart, configured to have a magnetic field within a space between the at least two electrodes; a conductive fiber, suspended between the at least two electrodes; in an air or fluid space subject to waves; wherein the conductive fiber has a radius and length such that a movement of at least a central portion of the conductive fiber approximates an oscillating movement of air or fluid surrounding the conductive fiber along an axis normal to the conductive fiber. An electrical signal is produced between two of the at least two electrodes, due to a movement of the conductive fiber within a magnetic field, due to viscous drag of the moving air or fluid surrounding the conductive fiber. The microphone may have a noise floor of less than 69 dBA using an amplifier having an input noise of 10 nV/?Hz.

Abstract: A microphone includes an outer casing, a carrier disposed in the outer casing, and a sound receiving module connected to the carrier. The carrier has a through hole opposite to the sound receiving module. An airtight unit includes a shock absorber and an airtight member cooperating with the outer casing and the carrier to define an airtight back chamber configured to generate a pneumatic wave when a mechanical vibration wave is transmitted to the outer casing. A damping material closes the through hole and is configured to change the phase of the pneumatic wave when the latter passes therethrough such that the pneumatic wave and the mechanical vibration wave can offset each other when they are transmitted to the sound receiving module.

Abstract: A communication system includes a processor and a computer readable medium, coupled with the processor, comprising instructions that program the processor to: cause an electromagnetic emitter to irradiate a location on a selected object in proximity to a speaker; determine, from radiation reflected by the selected object at the irradiated location, an audio characteristic of the irradiated location; and when the audio characteristic is acceptable, assigning an electromagnetic microphone to collect audio information from radiation reflected by the selected object at the irradiated location.

Abstract: The present disclosure provides a microphone adapted to be installed inside a case of an electronic device, an electronic device and a mobile terminal. The microphone includes a housing; a vibrating membrane set inside the housing, wherein the housing defines a sound collecting hole facing the vibrating membrane; and a connector adapted to connect the housing with the case of the electronic device and defining a first sound guiding tube and a second sound guiding tube; wherein, one end of the first sound guiding tube is communicated with the first sound entering hole while the other end of the first sound guiding tube is communicated with the second sound entering hole, a first end of the second sound guiding tube is communicated with the first sound guiding tube, and a second end of the second sound guiding tube is communicated with the sound collecting hole.

Abstract: A method of capturing audio includes initiating capture, at a laser microphone, of first audio of an area of interest. The first audio is captured while the laser microphone is focused on a first target surface associated with the area of interest. The method also includes generating adjustment parameters based on a feedback signal to adjust targeting characteristics of the laser microphone. The method further includes adjusting the targeting characteristics of the laser microphone based on the adjustment parameters to focus the laser microphone on a second target surface associated with the area of interest. The method also includes initiating capture, at the laser microphone, of second audio of the area of interest in response to adjusting the targeting characteristics. The second audio has an audio quality that is greater than the first audio.

Abstract: A system includes a laser microphone or laser-based microphone or optical microphone. The laser microphone includes a laser transmitter to transmit an outgoing laser beam towards a face of a human speaker. The laser transmitter acts also as a self-mix interferometry unit that receives the optical feedback signal reflected from the face of the human speaker, and generates an optical self-mix signal by self-mixing interferometry of the laser power and the received optical feedback signal; and a speckles noise reducer to reduce speckles noise and to increase a bandwidth of the optical self-mix signal. The speckles noise reducer optionally includes a vibration unit or displacement unit, to cause vibrations or displacement of one or more mirrors or optics elements of the laser microphone, to thereby reduce speckles noise.

Abstract: MEMS devices are disclosed including a MEMS microphone device comprising a first transducer adjoining a sound port, a second transducer not adjoining a sound port, a housing defining a shared volume for the first and second transducers, and circuitry arranged to combine a first signal from the first transducer and a second signal from the second transducer to produce an output signal.

Abstract: A microphone includes a first micro electro mechanical system (MEMS) motor, the first MEMS motor including a first diaphragm and a first back plate; and a second MEMS motor including a second diaphragm and a second back plate. The first diaphragm is electrically biased relative to the first back plate according to a first voltage, the second diaphragm is biased relative to the second back plate according to a second voltage, and a magnitude of the first voltage is different from a magnitude of the second voltage.

Abstract: An implanted microphone is provided that allows for isolating an acoustic response of the microphone from vibration induced acceleration responses of the microphone. The present invention measures the relative motion between a microphone diaphragm, which is responsive to pressure variations in overlying media caused by acoustic forces and acceleration forces, and a cancellation element that is compliantly mounted within a housing of the microphone, which moves primarily in response to acceleration forces. When the microphone and cancellation element move substantially in unison to acceleration forces, relative movement between these elements corresponds to the acoustic response of the microphone diaphragm. This relative movement may be directly measured using various optical measuring systems.

Abstract: A differential pressure transducer employing a coiled tube to eliminate varying pressure fluctuations is provided. In one embodiment, a method comprises receiving, at an inlet tube of a dampening chamber, a main pressure, wherein the main pressure includes a static pressure component and a dynamic pressure component; filtering, by the inlet tube, at least a portion of the dynamic pressure component of the main pressure; outputting, from the inlet tube, a first filtered main pressure; receiving, at a volume cavity of the dampening chamber, the first filtered main pressure, wherein the volume cavity is operatively coupled to the inlet tube; filtering, by the volume cavity, at least a portion of the dynamic pressure component of the first filtered main pressure; outputting, from the volume cavity, a second filtered main pressure; and wherein the dampening chamber is tuned to a predetermined resonance frequency.

Abstract: A microphone device includes a carrier board, a micro electro-mechanical system unit, an integrated circuit and an upper cover. The micro electro-mechanical system unit includes a substrate, a cap and a capacitive microphone. The cap is installed on the substrate, and is composed of electrically conductive material. The capacitive microphone is positioned between the cap and the carrier board, wherein the capacitive microphone and the cap form a resonant cavity. The integrated circuit is installed on the carrier board, and arranged to control the capacitive microphone. The upper cover is connected to the carrier board, wherein the micro-electro mechanical system unit and the integrated circuit are both positioned inside a space formed by the carrier board and the upper cover.

Abstract: Disclosed are systems, devices, and methods for minimizing mechanical-vibration-induced noise in audio signals. In one aspect, a microphone is disclosed that includes a first backplate, a first diaphragm, a second backplate, and a second diaphragm. The first diaphragm moves relative to the first backplate in response to acoustic pressure waves in an environment and mechanical vibrations of the microphone, thereby causing a first capacitance change between the first diaphragm and the first backplate. The second diaphragm is substantially acoustically isolated from the acoustic pressure waves, and moves relative to the second backplate in response to the mechanical vibrations of the microphone, thereby causing a second capacitance change between the second diaphragm and the second backplate. The microphone further includes or is communicatively coupled to an integrated circuit configured to generate an acoustic signal based on the first capacitance and the second capacitance.

Abstract: A micro-electro-mechanical system (MEMS) microphone module and a manufacturing process thereof are described. A thickness of a transparent temporary cover plate temporarily disposed in a conventional plastic package structure is adjusted. After a mold for a plastic protector is formed, an UV ray is utilized to irradiate the mold to reduce adherence on the temporary cover plate and a back surface of the MEMS acoustic wave sensing chip. Then, the temporary cover plate is removed, and the left space left is the main source for the back-volume of the MEMS microphone. Finally, a tag is covered on the plastic protector, so as to define the whole back-volume and form a closed back-volume. In the above-mentioned process, the size of the back-volume is the same as an area of the whole MEMS microphone chip. In addition, the back-volume can be defined.

Abstract: A microphone unit (1) is provided with an electro-acoustic transducer (13) which converts acoustic signals into electric signals on the basis of the oscillation of a diaphragm (134), and a housing (10) which contains the electro-acoustic transducer (13). The housing (10) is provided with: a first sound conduction space (SP1) that guides sound waves from the outside to one side of the diaphragm (134) via at least one first aperture (18) formed on the exterior of the housing (10); and a second sound conduction space (SP2) that guides sound waves from the outside to the other side of the diaphragm (134) via at least one second aperture (19) formed on the exterior of the housing (10). The total square area of at least one first aperture (18) and the total square area of at least one second aperture (19) are not the same.

Abstract: A microphone system has a base coupled with first and second microphone apparatuses. The first microphone apparatus is capable of producing a first output signal having a noise component, while the second microphone apparatus is capable of producing a second output signal. The first microphone apparatus may have a first back-side cavity and the second microphone may have a second back-side cavity. The first and second back-side cavities may be fluidly unconnected. The system also has combining logic operatively coupled with the first microphone apparatus and the second microphone apparatus. The combining logic uses the second output signal to remove at least a portion of the noise component from the first output signal.

Abstract: The invention is directed to systems, methods and computer program products associated with a microphone system for receiving a sound and producing an output signal representing the sound. The microphone system has a first microphone having a first dynamic range, the first microphone to receive the sound and produce a first sound signal based on the received sound. It also has a second microphone having a second dynamic range, the second microphone to receive the sound and produce a second sound signal based on the received sound, wherein the first dynamic range and the second dynamic range overlap thereby forming a transition dynamic range and processing logic operatively coupled to the first microphone and the second microphone. The processing logic is configured to receive the first sound signal from the first microphone, receive the second sound signal from the second microphone, and generate the output signal by combining the first sound signal and the second sound signal.

Abstract: An implantable microphone that includes a hermetically-sealed, enclosed volume and an electret member and back plate disposed with a space therebetween and capacitively coupleable to provide an output signal indicative of acoustic signals incident upon at least one of the electret member and back plate. At least one of the electret member and the back plate may include a plurality of laterally offset portions located in corresponding spatial relation to a plurality of laterally offset regions including the lateral extent of the space. The output signal may be at least one of weighted and weightable in relation to the plurality of laterally offset portions. The electret member may include the plurality of laterally offset portions, and the laterally offset portions may include at least one positively charged dielectric material portion and at least one negatively charged dielectric material portion.

Abstract: Representations of an object can comprise two or more separate sub-objects, producing a compound object. Compound objects can affect the quality of object visualization and threat identification. As provided herein, a compound object can be separated into sub-objects based on object morphological properties (e.g., an object's shape, surface area). Further, a potential compound object can be split into sub-objects, for example, eroding one or more outer layers of volume space (e.g., voxels) from the potential compound object. Additionally, a volume of a representation of the sub-objects in an image can be reconstructed, for example, by generating sub-objects that have a combined volume approximate to that of the compound object. Furthermore, sub-objects, which can be parts of a same physical object, but may have been erroneously split, can be identified and merged using connectivity and compactness based techniques.

Abstract: Microphone arrays (MAs) are described that position and vent microphones so that performance of a noise suppression system coupled to the microphone array is enhanced. The MA includes at least two physical microphones to receive acoustic signals. The physical microphones make use of a common rear vent (actual or virtual) that samples a common pressure source. The MA includes a physical directional microphone configuration and a virtual directional microphone configuration. By making the input to the rear vents of the microphones (actual or virtual) as similar as possible, the real-world filter to be modeled becomes much simpler to model using an adaptive filter.

Abstract: A miniaturized microphone maintaining the properties of a microphone chip and achieving a smaller mounting area. The microphone includes a package which includes a first and second member. At least one of the first second members includes a recess. The microphone also includes a circuit element installed on an inner surface of the first member. Additionally, the microphone includes a microphone chip arranged on a surface on an opposite side of an installing surface of the circuit element.

Abstract: A sound capture device comprises a symmetric microphone array that includes non-radially-oriented directional sensors (101). The device typically derives a spherical harmonic representation of the incident sound field, and affords higher signal-to-noise ratios and better directional fidelity than prior arrays, across a wide range of audio frequencies.

Abstract: Microphone arrays (MAs) are described that position and vent microphones so that performance of a noise suppression system coupled to the microphone array is enhanced. The MA includes at least two physical microphones to receive acoustic signals. The physical microphones make use of a common rear vent (actual or virtual) that samples a common pressure source. The MA includes a physical directional microphone configuration and a virtual directional microphone configuration. By making the input to the rear vents of the microphones (actual or virtual) as similar as possible, the real-world filter to be modeled becomes much simpler to model using an adaptive filter.

Abstract: A differential microphone having a perimeter slit formed around the microphone diaphragm that replaces the backside hole previously required in conventional silicon, micromachined microphones. The differential microphone is formed using silicon fabrication techniques applied only to a single, front face of a silicon wafer. The backside holes of prior art microphones typically require that a secondary machining operation be performed on the rear surface of the silicon wafer during fabrication. This secondary operation adds complexity and cost to the micromachined microphones so fabricated. Comb fingers forming a portion of a capacitive arrangement may be fabricated as part of the differential microphone diaphragm.

Abstract: To obtain a composite type microphone, the microphone preventing an increase in size and weight and thereby improving the freedom for installation and handling while keeping the phases of signals output from respective microphone units the same. A composite type microphone that incorporates microphone units of different electroacoustic conversion methods into a common microphone body is provided. Here, in a front acoustic terminal portion of a first microphone unit based on one electroacoustic conversion method, a second microphone unit based on another electroacoustic conversion method is disposed, and in the front acoustic terminal portion of the first microphone unit, an air that vibrates in the same phase with that of a vibrating plate of the first microphone unit exists, and within the air that vibrates in the same phase with that of the vibrating plate of the first microphone unit, the second microphone unit is disposed.

Abstract: A microphone having: a first bidirectional microphone unit formed by connecting two unidirectional microphone units, each of which has a vibrating section on a front side thereof, back to back; and a second bidirectional microphone unit formed by connecting two unidirectional microphone units, each of which has a vibrating section on a front side thereof, back to back, and a directional axis of the second bidirectional microphone unit is arranged to be shifted by 90 degrees with respect to a directional axis of the first bidirectional microphone unit.

Abstract: A directional microphone assembly for a hearing aid, and methods of assembling a directional microphone, are provided. The hearing aid has one or more microphone cartridge(s), and first and second sound passages. Inlets to the sound passages, or the sound passages themselves, are spaced apart such that the shortest distance between them is less than or approximately equal to the length of the microphone cartridge(s). A sound duct and at least one surface of a microphone cartridge may form each sound passage, where the sound duct is mounted with the microphone cartridge. Alternatively, each sound duct may be formed as an integral part of a microphone cartridge.

Abstract: A plurality of speakers are linked in the present invention. The linked position of each speaker can be detected. Audio signal is input to any one of the master speakers. The master speaker synchronizes the other linked speakers, and supplies audio signals to other speakers. It also controls the delay quantity of the speaker unit of each speaker. For a single speaker, the apparent width of this array speaker system becomes twice the width, and the speaker unit spacing becomes one third the spacing. Consequently, the frequency band at which direction is controllable becomes enhanced. Additionally, a plurality of microphone devices are linked at the top, bottom, left and right sides in the present invention. The linked position of each microphone device can be detected. Audio data is output from each microphone device to the master microphone device.

Abstract: In a hearing device with multiple microphones, and a signal generation method, the dynamic range of hearing devices is improved by using a combination including a silicon microphone and an electret microphone for the hearing device input. Low frequencies thus can be acquired by the silicon microphone and high frequencies can be acquired by the electret microphone, in order to generate a wide-band hearing device input signal. The fact that a silicon microphone possesses a lower internal noise than a conventional electret microphone at low frequencies is utilized.

Abstract: A sound capture device comprises a symmetric microphone array that includes non-radially-oriented directional sensors (101). The device typically derives a spherical harmonic representation of the incident sound field, and affords higher signal-to-noise ratios and better directional fidelity than prior arrays, across a wide range of audio frequencies.

Abstract: A wireless communication device such as a cell phone is rendered temporarily inoperable by enclosing the device in a container such as a heat sealable bag (1) which has been metallized so that when the device (2) is sealed in the container (1) it is surrounded by a metal layer (9) which blocks signals to and from the device (3) to thereby render it inoperable. The device is sealed within the container (1) by a seal such as a heat seal which will reveal any attempt to remove the device from the container.

Abstract: The invention concerns a microphone with a membrane. The membrane has a first side which is in fluid contact with the surroundings and a second side which is facing a back chamber, where a barometric relief opening or vent opening is provided between the back chamber and the surroundings. According to the invention control means are provided for controlling the barometric relief opening.

Abstract: A silicon condenser microphone package is disclosed. The silicon condenser microphone package comprises a transducer unit, substrate, and a cover. The substrate includes an upper surface having a recess formed therein. The transducer unit is attached to the upper surface of the substrate and overlaps at least a portion of the recess wherein a back volume of the transducer unit is formed between the transducer unit and the substrate. The cover is placed over the transducer unit and includes an aperture.

Abstract: A microphone pick-up device includes an air chamber unit disposed posteriorly of an annular cap body. A pick-up unit generates an acoustic signal in response to detected sound, and includes a yoke mounted in a front portion of the cap body, a voice coil disposed around a washer and a magnet within the yoke, a diaphragm for covering the yoke and connected to the voice coil, a sound regulating cloth attached to and disposed to surround the cap body, and a sound regulating paper disposed between a rear portion of the cap body and the air chamber unit and covering an air passage unit of the cap body. A signal filter is disposed between the rear portion of the cap body and the air chamber unit, is disposed posteriorly of the sound regulating paper, and is coupled to the voice coil for filtering noise in the acoustic signal.

Abstract: Microphone is disclosed having unmatched electroacoustic transducers. The microphone may be a traditional ECM microphone, or it may be a MEMS microphone. Each of the unmatched electroacoustic transducers may have its own peak frequency selected so that the electroacoustic transducers together produce a desirable resultant peak frequency. The unmatched electroacoustic transducers may have different package sizes, front volumes, back volumes, and/or diaphragm tensions, thicknesses, lengths, widths, and/or diameters. In some embodiments, the microphone may have different backplate charging and/or output signal amplification schemes for the electroacoustic transducers. Where the microphone is a MEMS microphone, voltage generation and output signal amplification are provided by an integrated circuit that may be mounted either within a front volume of one of the electroacoustic transducers or adjacent to one of the electroacoustic transducers.

Abstract: To obtain a composite type microphone, the microphone preventing an increase in size and weight and thereby improving the freedom for installation and handling while keeping the phases of signals output from respective microphone units the same. A composite type microphone that incorporates microphone units of different electroacoustic conversion methods into a common microphone body is provided. Here, in a front acoustic terminal portion of a first microphone unit based on one electroacoustic conversion method, a second microphone unit based on another electroacoustic conversion method is disposed, and in the front acoustic terminal portion of the first microphone unit, an air that vibrates in the same phase with that of a vibrating plate of the first microphone unit exists, and within the air that vibrates in the same phase with that of the vibrating plate of the first microphone unit, the second microphone unit is disposed.

Abstract: A process of forming a capacitive audio transducer, preferably having an all-silicon monolithic construction that includes capacitive plates defined by doped single-crystal silicon layers. The capacitive plates are defined by etching the single-crystal silicon layers, and the capacitive gap therebetween is accurately established by wafer bonding, yielding a transducer that can be produced by high-volume manufacturing practices.

Abstract: An eletrostatic microphone capsule includes a diaphragm which is subjected to a sound field and is excited to oscillate by the sound field, and an electrode arranged at a distance from the diaphragm. The electrode has at least two areas with different charge densities. The at least two areas may include an at least essentially circular area and an at least essentially annular area. At least two of the areas of the electrode may operate in accordance with the capacitor principle, wherein different voltages are applied to the areas.

Abstract: A condenser microphone has a conductive diaphragm 3 having an earth electrode layer 31 formed of a conductive light metal; a conductor fixed electrode 5 arranged opposite to the conductive diaphragm 3 through an air layer; an organic dielectric layer 32 formed of the organic compound provided on the boundary surface 32C side between the air layer and the conductive diaphragm 3; and a permanent electric charge layer 32A composed of ions or electrons formed in the inner portion side receding from the air layer 8side, from a middle position in the thickness direction of the organic dielectric layer 32 in the inside of the organic dielectric layer 32.

Abstract: The present invention relates to an electret condenser microphone including the vibratory diaphragm which is comprised of an electret film into which an electric charge is charged; a conductive film formed on one side of the electret film by sputtering or chemical vapor deposition (CVD); and a polar ring disposed at a peripheral edge of the underside of the conductive film such that the conductive film formed on the electret film is located apart from the inner surface of the case at a given distance (&Dgr;t). Also, this microphone includes a vibratory diaphragm support member which is disposed on the vibratory diaphragm and has a concave groove and a concave portion. The concave portion has a plurality of sound holes which are formed at a bottom surface thereof such that the vibratory diaphragm is vibrated easily. On the vibratory diaphragm support member is attached an integrated circuit serving to receive and amplify a transformed electrical signal from the vibratory diaphragm.

Abstract: A device for collecting sounds from objects comprises a plurality of microphones whose directivity can be varied depending on the environment in which each object is located. An optical microphone includes a vibration board (2) which vibrates by sound pressure, a light source (3) for emitting a light beam to the vibration board (2), a photodetector (5) which receives the light beam reflected from the vibration board (2) and produces a signal corresponding to the vibration of the vibration board (2), a drive circuit (13) for supplying the light source (3) with predetermined current, and a negative feedback circuit (100) that supplies the drive circuit (13) with a negative feedback signal consisting of a signal output from the photodetector (5). The negative feedback circuit (100) changes the amount of negative feedback depending on the environment.

Abstract: An optical microphone element comprising a diaphragm (31) vibrating with sound pressure, a case (40) containing the diaphragm (31) and having first and second openings (38, 39) made in symmetric positions and facing the diaphragm (31), a light source (32) for irradiating the diaphragm (31) with a light beam, and a photodetector (35) for receiving the light beam reflected by the diaphragm (31) and outputting a signal corresponding to vibration of the diaphragm (31).

Abstract: A device for collecting sounds from objects comprises a plurality of microphones whose directivity can be varied depending on the environment in which each object is located. An optical microphone includes a vibration board (2) which vibrates by sound pressure, a light source (3) for emitting a light beam to the vibration board (2), a photodetector (5) which receives the light beam reflected from the vibration board (2) and produces a signal corresponding to the vibration of the vibration board (2), a drive circuit (13) for supplying the light source (3) with predetermined current, and a negative feedback circuit (100) that supplies the drive circuit (13) with a negative feedback signal consisting of a signal output from the photodetector (5). The negative feedback circuit (100) changes the amount of negative feedback depending on the environment.

Abstract: A vibration detecting unit is arranged in an air chamber in communication with a microphone unit and changes in pressure in the air chamber caused by the vibrations of a diaphragm of the vibration detecting unit is transmitted to the back surface side of a diaphragm of the microphone unit thereby suppressing the displacement of the diaphragm caused by external vibrations.

Abstract: An optical microphone includes a laser and beam splitter cooperating therewith for splitting a laser beam into a reference beam and a signal beam. A reflecting sensor receives the signal beam and reflects it in a plurality of reflections through sound pressure waves. A photodetector receives both the reference beam and reflected signal beam for heterodyning thereof to produce an acoustic signal for the sound waves. The sound waves vary the local refractive index in the path of the signal beam which experiences a Doppler frequency shift directly analogous with the sound waves.

Abstract: An improved, single diaphragm SOD microphone uses acoustic filters to remove resonances associated with the ducting that guides the ambient sound pressure to the front and rear faces of a FOD microphone element. The microphone element communicates with respective front and rear chambers, two ports communicate with the front chamber via front conduits, and two ports communicate with the rear chamber via rear conduits. The microphone further comprises first and second side chambers for dissipating acoustic energy of undesired resonances. The first side chamber communicates with the front conduits, and the second side chamber communicates with the rear conduits. In specific embodiments of the invention, each of the side chambers comprises a branch conduit approximately equal in length to one-quarter wavelength of an undesired resonance. In certain embodiments, each of these branch conduits includes a small neck joining the branch conduit to its corresponding front or rear conduits.

Abstract: An improved Broadside SOG microphone assembly is realized by employing a microphone assembly having at least three ports arranged in a non-colinear fashion with the at least three ports defining and being in a "gradient" plane and with both outer adjacent differential pair of ports aligned in a direction substantially toward a prospective talker's lips. Thus, the inner port(s) is always closer to the prospective talker's lips. Each outer differential pair of ports forms a dipole which yields a high spatial gradient and, hence, higher speech sensitivity since they are pointed substantially toward the prospective talker's lips. Just as important, as the prospective talker's lip position relative to the microphone varies, this alignment of each outer differential pair of ports will result in the least change in the dipole sensitivity and, therefore, the lowest Broadside SOG microphone position sensitivity.

Abstract: A second-order differential (SOD) microphone includes a first-order differential (FOD) microphone element installed in a housing. A pair of front sound conduits extend from respective ports to a chamber on the front side of the microphone diaphragm, and a pair of rear sound conduits extend from respective ports to a chamber on the rear side of the microphone diaphragm. The two front ports and the two rear ports are all substantially collinear along a minor axis, with the rear ports intermediate the front ports or the front ports intermediate the rear ports. The respective acoustic transfer functions from each port to the microphone diaphragm are equivalent. The microphone response is approximately proportional to the second spatial derivative, along the minor axis, of a sample acoustic pressure field.