Abstract: A transducer includes a first piezoelectric layer; and a second piezoelectric layer that is above the first piezoelectric layer; wherein the second piezoelectric layer is a more compressive layer with an average stress that is less than or more compressive than an average stress of the first piezoelectric layer.

Abstract: An audio rendering system includes a processor that combines audio input signals with personalized spatial audio transfer functions having room responses. The personalized spatial audio transfer functions are selected from a database having a plurality of candidate transfer functions derived from in-ear microphone measurements for a plurality of individuals. Alternatively, the personalized transfer functions are derived from actual in-ear measurements of the listener. A room modification module allows the user to modify the personalized spatial audio transfer functions to substitute a different room or to modify the characteristics of the selected room without requiring additional in ear measurements. The module segments the selected transfer function into regions including one or more of direct; head and torso influenced; early reflection, and late reverberation regions. Extraction and modification operations are performed on one or more of the regions to alter the perceived sound.

Abstract: The present application discloses a system for converting vibration to voice frequency wirelessly and a method thereof. By sensing a first vibration variation data and a voice frequency variation data of a vocal vibration part in a first sensing period, a voice frequency reference data is obtained from the voice frequency variation data and the first vibration result. A second vibration result is obtained at a second sensing period for converting to a voice frequency output signal, and the voice frequency output signal is used to output as a voice signal corresponding to the voice frequency various result. Thus, the present application provides a voice signal close to a human voice.

Abstract: A low-frequency loudspeaker is provided comprising an enclosure having a front, a back and a sidewall. An audio speaker is mounted in an opening in the front of the enclosure. The audio speaker has a diaphragm for producing front sound waves that are transmitted outwardly from the diaphragm and back sound waves that are transmitted into the enclosure from the diaphragm. A spiral waveguide is positioned within the enclosure. The spiral waveguide has a first end proximal to the speaker diaphragm for receiving the back sound waves and extends outwardly therefrom in a spiral pattern to a second end that forms a low-frequency terminus exit port opening in the sidewall.

Abstract: A MEMS sound transducer for generating and/or detecting sound waves in the audible wavelength spectrum includes a carrier: a diaphragm connected to and deflectable with respect thereto the carrier and a piezoelectric element spaced apart from the diaphragm along a reciprocation axis. The piezoelectric element includes a coupling element that extends along the reciprocation axis and connects to the diaphragm. The piezoelectric element and the coupling element form a cantilever. The MEMS sound transducer includes two cantilever arms are arranged one behind the other, in a top view.

Abstract: The present application provides a piezoelectric microphone including a substrate having a back cavity and a piezoelectric cantilever diaphragm fixed to the substrate, the piezoelectric cantilever diaphragm includes a fixed end fixedly connected to the substrate and a movable end connected to the fixed end and suspended above the back cavity, the piezoelectric microphone further includes a support back plate, the support back plate includes a support arm opposite to and spaced apart from the movable end of the piezoelectric cantilever diaphragm and a fixing arm that fixes the support arm. The piezoelectric microphone of the present disclosure has better stability compared to the related art.

Abstract: A piezoelectric MEMS transducer formed in a body of semiconductor material, which has a central axis and a peripheral area and comprises a plurality of beams, transverse to the central axis and having a first end, coupled to the peripheral area of the body, and a second end, facing the central axis; a membrane, transverse to the central axis and arranged underneath the plurality of beams; and a pillar, parallel to the central axis and rigid with the second end of the beams and to the membrane. The MEMS transducer further comprises a plurality of piezoelectric sensing elements arranged on the plurality of beams.

Abstract: The present application provides a piezoelectric microphone, and it includes a substrate having a back cavity and a piezoelectric cantilever diaphragm fixed to the substrate. The piezoelectric cantilever diaphragm includes a plurality of diaphragm flaps, and each of the diaphragm flaps has one end fixed to the substrate and another end suspended above the back cavity. Every two adjacent ones of the diaphragm flaps are spaced apart to form a gap. The piezoelectric microphone further comprises an elastically stretchable member connecting the two adjacent diaphragm flaps, and the elastically stretchable member is provided between at least one set of two adjacent ones of the diaphragm flaps. The piezoelectric microphone of the present disclosure has better performance.

Abstract: A head-mounted wearable device (HMWD) provides audio output using acoustic quadrupole units (AQU). The AQU produces an acoustic pattern having a first region and a second region. The first region has a first phase and the second region has a second phase that is opposite the first phase. A major axis extending through the regions is directed generally upwards from the ear canal of the user. The ear of the user is within the first region. The second region is directed upward. Bystanders are within an acoustically null region of the acoustic pattern. The acoustically null region is perpendicular to the major axis. Within the acoustically null region, the sound intensity is reduced due to destructive interference between the first phase and the second phase. As a result, the user wearing the HMWD is able hear audio output while audio amplitude perceived by the bystanders is significantly reduced.

Abstract: A piezoelectric MEMS transducer formed in a body of semiconductor material, which has a central axis and a peripheral area and comprises a plurality of beams, transverse to the central axis and having a first end, coupled to the peripheral area of the body, and a second end, facing the central axis; a membrane, transverse to the central axis and arranged underneath the plurality of beams; and a pillar, parallel to the central axis and rigid with the second end of the beams and to the membrane. The MEMS transducer further comprises a plurality of piezoelectric sensing elements arranged on the plurality of beams.

Abstract: Offset cartridge microphones are provided that include multiple unidirectional microphone cartridges mounted in an offset geometry. Various desired polar patterns and/or desired steering angles can be formed by processing the audio signals from the multiple cartridges, including a toroidal polar pattern. The offset geometry of the cartridges may include mounting the cartridges so that they are immediately adjacent to one another and so that their center axes are offset from one another. The microphones may have a more consistent on-axis frequency response and may more uniformly form desired polar patterns and/or desired steering angles by reducing the interference and reflections within and between the cartridges.

Abstract: Disclosed is a loudspeaker module comprising a module housing, wherein a loudspeaker unit is accommodated in the module housing; the loudspeaker unit comprises a unit housing and a unit front cover; an end surface of a sidewall of at least one side of the unit housing is provided with an ultrasonic surface welded to the module housing by means of ultrasound; and an ultrasonic line bonded with the ultrasonic surface by means of ultrasound is provided at a position on the module housing corresponding to the ultrasonic surface. The loudspeaker module of the present invention solves the technical problems of a complex assembly process, poor sealing performance and poor appearance of the loudspeaker module in the prior art, and the loudspeaker module of the present invention has a simple assembly process, good sealing performance, high quality appearance, excellent acoustic performance, high production efficiency and low production cost.

Abstract: A method for inspecting a pressure pulse wave sensor is provided. The sensor chip includes a recess which is recessed in a direction perpendicular to the pressure-sensitive face, and the pressure-sensitive element array is formed in a portion of the sensor chip whose thickness is reduced in the direction due to the recess. The method includes: bonding and fixing the sensor chip onto the substrate so that the recess communicates with atmospheric air through only the through hole of the substrate; connecting a substrate-side terminal portion of the substrate and the chip-side terminal portion through an electrically conductive member; and performing characteristic evaluation on the sensor chip based on a signal outputted from the substrate-side terminal portion in a state in which air is sucked through the through hole of the substrate to thereby apply negative pressure to the pressure-sensitive face.

Abstract: The present invention relates to a microphone module comprising a first directional microphone comprising a front sound inlet and a front membrane, a second directional microphone comprising a rear sound inlet and a rear membrane, and a middle sound inlet arrangement being acoustically connected to the front and rear membranes, said middle sound inlet arrangement comprising acoustical resistance means arranged at least partly therein. The microphone module aims at generating a cardioid and an anti-cardioid response, or alternatively any other back-to-back polar patterns.

Abstract: Aspects of the disclosure provide a packaging technique for making a directional microphone which employs mechanical structures to cancel undesired background noise to realize the directional function instead of an extra sensor required in electronic noise-cancelling techniques, thus reducing footprint and cost of a directional microphone. A directional microphone based on this technique can include an acoustic sensor and a housing enclosing the acoustic sensor. The acoustic sensor can include a sensing diaphragm, a cavity below the sensing diaphragm, and a first substrate. The directional microphone device can further includes a channel with an inlet open at an edge of the first substrate and an outlet connected with the cavity. The housing can include a cover attached to a second substrate supporting the first substrate. The cover can include a first opening over the sensing diaphragm and a second opening at a side of the cover.

Abstract: An electroacoustic transducer comprises a sleeve extending along a longitudinal axis; a diaphragm coupled to the sleeve at a first end of the sleeve; a subassembly in the sleeve; and an alignment element extending from the subassembly in a direction substantially away from the diaphragm.

Abstract: A resilient element is used to bias a vibration element of an auditory prosthesis towards the skin of a recipient. This helps improve transmission of vibration stimuli to the recipient. Additionally, the resilient element helps reduce feedback caused by the vibration element vibrating in close proximity to sound processing components contained within the auditory prosthesis.

Abstract: A hearing instrument microphone device incudes at least two microphone sound ports (or sound inlets), a pressure difference microphone in communication with at least two of the sound ports and a pressure microphone in communication with at least one of the sound ports, wherein the acoustic centers of the pressure difference microphone and the pressure microphone essentially coincide.

Abstract: Embodiments are disclosed for a loudspeaker driven by one or more piezoelectric actuators. In embodiments of the disclosure, a loudspeaker comprises a support structure, and a piezoelectric layered cantilever actuator affixed to the support structure via at least two grips. The support structure may also comprise a membrane suspended over the piezoelectric actuator, the membrane being in contact with the piezoelectric actuator between the at least two grips.

Abstract: An electro-acoustic transducer includes a base, a plurality of vibration portions and a connection portion. Each of the vibration portion includes a piezoelectric transduction layer and has a first connection end and a second connection end opposite to each other, and the first connection ends are connected to the base. The connection portion is separated from the base and connected to the second connection ends. The piezoelectric transduction layers are adapted to receive electrical signals to deform, such that the vibration portions are driven to vibrate and generate corresponding acoustic waves. The vibration portions are adapted to receive acoustic waves to vibrate, such that the piezoelectric transduction layers are driven to deform and generate corresponding electrical signals.

Abstract: A monolithic electrode includes a first portion devoid of apertures and a second portion surrounded by the first portion, the second portion having a web defining a plurality of apertures. A method for forming an electrode includes forming a first electrode portion devoid of apertures and forming a second electrode portion having a web defining a plurality of apertures. The web of the second electrode portion connects to the first electrode portion.

Abstract: The invention relates to a microphone (10). A first (14a) and a second (14b) diaphragm are provided in a housing (12). A first chamber (24a) is delimited by a first side of the first diaphragm (14a) and an inner surface of the housing (12). A first opening (18a) extends from the first chamber (24a) to surroundings of the microphone (10). A second chamber (24b) is delimited by a first side of the second diaphragm (14b) and an inner surface of the housing (12). A second opening (18b) extends from the second chamber (24b) to the surroundings. A common chamber (22) is delimited by a second side of the first diaphragm (14a), a second side of the second diaphragm (14b) and an inner surface of the housing (12). A third opening (20) extends from the common chamber (22) to the surroundings.

Abstract: An ultrasonic transducer with housing contains a transducer assembly, an outer housing surface being fixed against a barrier surface for transferring ultrasonic waves to and from a barrier. The housing has an inner surface with plateau. A cap closes the housing and the transducer assembly has a piezoelectric transducer with a pressure surface around its outer perimeter and an opposite vibration surface engaging the plateau. A ring engages the pressure surface for biasing the vibration surface against the plateau. A holder engages the cap, transducer and ring for positioning and a plurality of springs are spaced around the transducer perimeter and between the cap and ring for biasing the vibration surface toward or against the raised plateau. A viscous couplant is between the vibration surface and plateau for enhancing transmission of the ultrasonic waves.

Abstract: A handheld microphone includes a microphone unit supported with a vibration insulator on a microphone case; the handheld microphone comprising a filter circuit for filtering output signals from the microphone unit; the filter circuit comprising a passive filter connected to an output terminal of the microphone unit, and a high-pass filter connected downstream of the passive filter and outputting the filtered signals from the microphone unit.

Abstract: A unidirectional condenser microphone includes a first and second condenser elements each having a diaphragm and a fixed electrode disposed opposite the diaphragm, an insulating base having an opening at the center thereof and supporting the respective fixed electrodes of the first and second condenser elements at opposite sides of the insulating base, acoustic resistance materials covering both ends of the opening, and air chambers formed respectively between each of the fixed electrodes and the insulating base, such that respective back sides of the diaphragms of the first and the second condenser elements are acoustically in communication with each other, wherein the diaphragm of the second condenser elements is formed to be an annular-shape having a central opening, and the second condenser element has a rear acoustic terminal hole communicating with the central opening.

Abstract: A silicon condenser microphone is disclosed. The silicon condenser microphone includes a substrate including a side surrounding a cavity, a transducer unit supported by the substrate, a partition positioned in the cavity of the substrate for dividing the cavity into an upper cavity and a lower cavity. The transducer unit includes a backplate and a diaphragm forming a capacitor. The partition includes a main body connected to an inner surface of the side of the substrate, and a perforation penetrating the main body for communicating the upper cavity with the lower cavity. The sensitivity of the silicon condenser microphone is accordingly improved.

Abstract: A portable electronic device that provides compact configurations for audio elements are disclosed. The audio elements can be drivers (e.g., speakers) or receivers (e.g., microphones). According to one aspect, mesh structures, such as mesh barriers, are formed to facilitate improved acoustic sealing in a space efficient manner. In one embodiment, a mesh barrier for an audio port can be reliably acoustically sealed (or coupled) with an audio chamber and/or outer device housing in a space efficient manner. A mesh barrier can serve to block undesired foreign substances from entry or further entry into an audio port and/or serve as a cosmetic barrier which obscures vision into an audio port. In one embodiment, a portion of a mesh structure can be provided with a substantially planar surface that facilitates improved acoustic sealing.

Abstract: A microphone and method of manufacturing the microphone are provided. The microphone includes a substrate that has a penetration aperture, a vibration film disposed on the substrate that covers the penetration aperture, and a first electrode disposed on the vibration film. The first electrode includes a first portion and a second portion separated from each other. In addition, the microphone includes a piezoelectric layer disposed on the second portion of the first electrode, a second electrode disposed on the piezoelectric layer, and a fixed electrode. Further, the first portion of the first electrodes is disposed at a substantially center portion of the vibration film and the second portion of the first electrode is disposed at an edge portion of the vibration film.

Abstract: The invention relates to a microphone (10). A first (14a) and a second (14b) diaphragm are provided in a housing (12). A first chamber (24a) is delimited by a first side of the first diaphragm (14a) and an inner surface of the housing (12). A first opening (18a) extends from the first chamber (24a) to surroundings of the microphone (10). A second chamber (24b) is delimited by a first side of the second diaphragm (14b) and an inner surface of the housing (12). A second opening (18b) extends from the second chamber (24b) to the surroundings. A common chamber (22) is delimited by a second side of the first diaphragm (14a), a second side of the second diaphragm (14b) and an inner surface of the housing (12). A third opening (20) extends from the common chamber (22) to the surroundings.

Abstract: Capacitive micromachined ultrasonic transducers (CMUTs) having a pre-charged floating electrode are provided. Such CMUTs can operate without an applied DC electrical bias. Charge can be provided to the floating electrode after or during fabrication in various ways, such as injection by an applied voltage, and injection by ion implantation.

Abstract: An apparatus including a flexible circuit having a flexible substrate and at least one electrical conductor; and a least one piezoelectric member adapted to move when a voltage is applied to the piezoelectric member. The piezoelectric member is mounted to a first side of the flexible substrate and electrically connected to at least one of the electrical conductors.

Abstract: A microphone package for providing a modified microphone signal includes a microphone and an equalizer device coupled to the microphone.

Abstract: Provided are an acoustic sensor and a method of manufacturing the same. The acoustic sensor includes a substrate including an acoustic chamber, a first hole, and a second hole, penetrating the substrate, a lower electrode pad extended onto a top surface of the substrate while covering a sidewall of the first hole, a diaphragm pad extended onto the top surface of the substrate while covering a sidewall of the second hole, a lower electrode provided on the acoustic chamber and connected to the lower electrode pad, and a diaphragm above the lower electrode while being separated from the lower electrode and connected to the diaphragm pad.

Abstract: A piezoelectric sound component that includes a resin sheet, a piezoelectric diaphragm, and a casing. The piezoelectric diaphragm vibrates by bending, and is attached to at least part of a central portion of the resin sheet excluding a peripheral portion of the resin sheet. The casing holds the peripheral portion of the resin sheet. The casing supports at least one corner portion of the piezoelectric diaphragm.

Abstract: A low profile ultrasonic emitter comprises a support member operable to support an ultrasonic emittive material, the support member including a plurality of support ribs, each support rib being spaced from adjacent support ribs and extending longitudinally along the support member. An ultrasonic emittive film is coupled to upper portions of the support ribs so as to be carried by the support member. A first electric lead is coupled to a first face of the emittive film and a second electric lead coupled to an opposing face of the emittive film. The first and second leads are coupled to their respective faces adjacent one another but staggered from one another so as to not overlap one another when the film is positioned between the leads.

Abstract: A sound pickup system is disclosed. The sound pickup system includes a screen, an accelerometer attached to the screen, and a pre-processing module electrically connecting with the accelerometer. The screen is configured to detect a vibration caused by sound waves, the accelerometer is configured to receive the vibration detected by the screen and convert the vibration into an acceleration signal, and the pre-processing module is configured to receive the acceleration signal, and process the acceleration signal then convert the processed acceleration signal into a voice signal.

Abstract: There are provided a vibration film (21) having a piezoelectric element, a magnetic circuit (20) which generates magnetic force on the basis of a first electric signal and vibrates the vibration film (21) by the magnetic force; and an adjustment unit (31) which generates a second electric signal on the basis of the first electric signal and applies a voltage based on the second electric signal between both surfaces of the piezoelectric element. The amplitude of the entire vibration film (21) is expanded by making the vibration by the magnetic force, which is generated from the magnetic circuit (20), and the vibration, which is generated by application of a voltage to the piezoelectric element, synchronize with each other.

Abstract: Provided is an acoustic generator which has a high sound pressure at ultrahigh frequencies and which can suppress occurrence of large peak dips. An acoustic generator includes a film, a frame member disposed on an outer peripheral edge of the film, a piezoelectric element disposed on the film and inside the frame member, and a resin layer filled inside the frame member so as to cover the piezoelectric element.

Abstract: In an embodiment an apparatus includes a graphical display panel and a loudspeaker. The panel has a display layer for displaying images and defines a plurality of apertures penetrating through at least the display layer. The loudspeaker includes a diaphragm arranged substantially parallel to the display layer. Sound from the loudspeaker diaphragm is directed outside a host device through the apertures. The speaker may be an electret or a piezo-electric speaker for thinness. There may be apertures on an opposed side of the host device housing to achieve a dipole pattern which is directed and gives acoustic privacy to the user, or a rear acoustic cavity for a monopole pattern which more broadly disperses the sound. One illustrated embodiment is selectable between monopole and dipole. Size and total area of the holes determines acoustic resistance and so a method is described to determine those from physical parameters of the display panel.

Abstract: Disclosed is a piezoelectric speaker including: a piezoelectric layer that converts electrical signals into oscillation and outputs sound; an electrode that is formed on a top or a bottom of the piezoelectric layer to apply the electrical signals to the piezoelectric layer; an acoustic diaphragm that is made of a hetero material including a first acoustic diaphragm and a second acoustic diaphragm and is attached to the bottom of the piezoelectric layer on which the electrode is formed; and a frame attached in a form enclosing a side of the acoustic diaphragm.

Abstract: A microphone base includes a plurality of metal layers and a plurality of core layers. Each of the plurality of core layers is disposed between selected ones of the metal layers. A dielectric membrane is disposed between other selected ones of the plurality of metal layers. A port extends through the metal layers and the core layers but not through the dielectric membrane. The dielectric membrane has a compressed portion and an uncompressed portion. The uncompressed portion extends across the port and the compressed portion is in contact with the other selected ones of the metal layers. The compressed portion of the membrane is effective to operate as a passive electronic component and the uncompressed portion is effective to act as a barrier to prevent at least some external debris from traversing through the port.

Abstract: Audio apparatus comprising a housing and a piezoelectric transducer (12) mounted in the housing (10) so that the transducer is adjacent a user's pinna whereby the transducer excites vibration in the pinna to cause it to transmit an acoustic signal from the transducer to a user's inner ear characterised by comprising a coupler (14) coupling the transducer (12) to the housing (10) with the coupler (14) approximating to a simple support for the transducer (12).

Abstract: The present invention provides a reverse-phase modulating structure of a piezoelectric ceramic speaker, comprising a positioning frame, an acoustic generator and two or more than two flexible units; wherein the acoustic generator comprises a plurality of ceramic layers stacked onto one another to form a ceramic slat, and said flexible units are clamped between an inner edge of the positioning frame and the acoustic generator. Via the pressure exerted onto the acoustic member by the flexible units, the in-phase movement of the acoustic generator can be modulated and the phase conflict of the acoustic generator can be reduced as well as the prevision of the sound quality distortions such that high quality of the ceramic speaker can be enhanced and realized.

Abstract: A piezoelectric speaker includes a cover with a receiving space and a vibrating speaker unit accommodated in the receiving space. The vibrating speaker unit includes a piezoelectric oscillator including an upper surface and an lower surface, a diaphragm disposed on the upper surface of the piezoelectric oscillator, and a vibrating member kept a distance from the lower surface of the piezoelectric oscillator. The piezoelectric oscillator defines a first amplitude capable of driving the diaphragm only and a second amplitude driving both the vibrating member to vibrating with a largest amplitude and the diaphragm to generate sound. The distance is larger than the first amplitude and smaller than the second amplitude.

Abstract: This disclosure provides systems, methods and apparatus for sense elements in an electromechanical microphone device. In one aspect, a piezoelectric sense element may include a glass substrate, electrode layers, piezoelectric layers, and elastic layers. The elastic layers may serve to modify the neutral plane of the piezoelectric sense element. Including an elastic layer or layers to modify the neutral plane of the piezoelectric sense element may serve to configure the sense element such that the piezoelectric layer generates a voltage in response to a sound wave or may serve to increase the sensitivity of the sense element.

Abstract: A vibrating electrode plate 24 that senses a sound pressure faces a counter electrode plate 25 to form a capacitance type acoustic sensor. Acoustic perforations are opened in the counter electrode plate 25 in order to allow vibration to pass through. The acoustic perforations opened in the counter electrode plate 25 include plural acoustic perforations 31 having a relatively small opening area and one acoustic perforation 36 having a relatively large opening area. The acoustic perforations 31 and 36 are disposed into a lattice shape at equal intervals. Assuming that L is a width of a diaphragm 28, in the counter electrode plate 25, the acoustic perforation 36 having the large opening area is provided within a circular region a having a radius r=L/4 around a position facing a center of the diaphragm 28.

Abstract: A piezoelectric actuator 60 includes a piezoelectric element 10 expanding and contracting according to a state of an electric field, a pedestal 20, a vibration film 30, and a support member. In the vibration mode of the divided vibration occurring in the piezoelectric actuator in a high frequency band, one or more reinforcement members 50 are selectively disposed on an upper surface or a lower surface of the piezoelectric element 10, in a region where a node of divided vibration occurs. With such configurations, the vibration mode can be changed in the piezoelectric element 10. Therefore, in the frequency sound pressure level characteristics, the divided vibration causing hills or valleys (peaks or dips) can be effectively suppressed, thus enabling the achievement of flatness of frequency sound pressure level characteristics and of reproduction of excellent sound.

Abstract: A piezoelectric acoustic transducer achieves both space-saving and high sound quality without increasing the number of parts. In order to achieve this, the transducer includes a piezoelectric element constructed of a piezoelectric material interposed between two surface electrodes and a diaphragm of which at least one principal surface is provided with a print wiring and at least one principal surface is bonded to the piezoelectric element. The diaphragm includes a frame section, a vibrating section which is bonded with the piezoelectric element and which vibrates, and at least one supporting section which connects the frame section and the vibrating section and which supports the vibrating section. Either the frame section or the at least one supporting section includes at least one electrical resistance which is integrally formed to the print wiring and which constructs, in combination with the piezoelectric element, a series-RC circuit.

Abstract: A piezoelectric MEMS microphone comprising a multi-layer sensor that includes at least one piezoelectric layer between two electrode layers, with the sensor being dimensioned such that it provides a near maximized ratio of output energy to sensor area, as determined by an optimization parameter that accounts for input pressure, bandwidth, and characteristics of the piezoelectric and electrode materials. The sensor can be formed from single or stacked cantilevered beams separated from each other by a small gap, or can be a stress-relieved diaphragm that is formed by deposition onto a silicon substrate, with the diaphragm then being stress relieved by substantial detachment of the diaphragm from the substrate, and then followed by reattachment of the now stress relieved diaphragm.

Abstract: A microphone includes a first diaphragm and a second diaphragm coupled to the first diaphragm by a closed air volume. The first diaphragm and the second diaphragm each constitutes a piezoelectric diaphragm. The first diaphragm and the second diaphragm are electrically coupled so that movement of the first diaphragm causes movement of the second diaphragm.