Abstract: Provided is a unidirectional microphone including ribbon diaphragms which is reduced in dimensions. The microphone includes a bidirectional ribbon microphone unit and an omnidirectional condenser microphone unit. The ribbon microphone unit includes a pair of ribbon diaphragms. The condenser microphone unit is disposed between the pair of ribbon diaphragms.

Abstract: A non-directional microphone includes a housing, a microphone unit attached to the housing, and including a diaphragm that receives a sound wave, and a connector portion to which a cable connector including a cable that transmits an audio signal from the microphone unit is connected, and a pressure equalization opening that allows a back-side space of the diaphragm in the housing and an outer space to communicate is provided in the connector portion. In the non-directional microphone, the communication between the back-side space of the diaphragm and the outer space through the pressure equalization opening is cut off when the cable connector is connected to the connector portion, and the back-side space of the diaphragm communicates into the outer space through the pressure equalization opening when the cable connector is disconnected from the connector portion.

Abstract: To prevent penetration of water into a microphone unit side even if the rain falls on a cylindrical acoustic tube in a narrow directional microphone using the acoustic tube. The narrow directional microphone includes a cylindrical acoustic tube base portion, the acoustic tube base portion includes at least one slit-like opening extending along a longitudinal direction of the acoustic tube base portion, a plurality of short fibers are implanted in an outer peripheral surface of the acoustic tube base portion and base portion edge surfaces that form the opening, and the opening is covered with the short fibers.

Abstract: In an impedance converter using an electron tube as an active element, output impedance can be made sufficiently low, and the number of circuit elements therefor is decreased and a circuit configuration therefor is made simple. Provided is an impedance converter having an electron tube cathode-follower connected. The impedance converter includes a bias diode that provides a bias voltage to a cathode of the electron tube, high resistance elements that provide a voltage of the bias diode to a grid of the electron tube, a load circuit connected to the electron tube, and a complementary emitter output circuit including two transistors, respective bases of which are connected to one end and the other end of the bias diode.

Abstract: A microphone with a stable electromagnetic shield includes a microphone case having a shape of a hollow cylinder with a bottom end, the microphone case having an opening, an inner circumferential surface, an exterior and an interior, a microphone unit accommodated in the microphone case, a cord bush through which a microphone cord outputting audio signals from the microphone unit passes, the cord bush being fit to the opening of the microphone case, a sound transmission material accommodated in the microphone case, and a communication path establishing communication between the exterior and the interior of the microphone case. The cord defines a part or a whole of the communication path. The communication path is covered by the sound transmission material from the front of the communication path.

Abstract: In a primary sound pressure-gradient type condenser microphone unit driving a diaphragm by difference in sound pressure applied to acoustic terminals in front and back of the diaphragm, a drive force of the diaphragm and sound collection characteristics in a high frequency band are easily adjusted. The condenser microphone unit includes a first pipe extending forward on the front side of a diaphragm and a second pipe arranged so as to surround the first pipe. A front acoustic terminal communicating with a front surface of the diaphragm is formed on an inner side of either one of the first pipe or the second pipe. A rear acoustic terminal communicating with a back surface of the diaphragm from the rear side of a fixed electrode is formed on an inner side of the other pipe.

Abstract: A condenser microphone includes a first grounded-plate electron tube having a plate to which a dc power is supplied, and a cathode provided with an output terminal, a self-biasing circuit that is connected to the cathode of the first electron tube and that generates a grid bias voltage of the first electron tube by voltage drop with a cathode current, and a second grounded-cathode electron tube having a plate to which a series circuit of the first electron tube and the self-biasing circuit is connected as a load circuit. A positive phase output from a first condenser microphone unit is supplied to a grid of the first electron tube, and a reverse phase output from a second condenser microphone unit is supplied to a grid of the second electron tube.

Abstract: A condenser microphone unit that has a capacitor element with a large effective area and a high signal-noise ratio but does not have frequency-dependence occurring with sound waves beyond the audio frequency range. A solid cylindrical fixed electrode pole is used as a fixed electrode. A diaphragm includes a rectangular synthetic resin film having a length smaller than or equal to the axis length of the fixed electrode pole, and a width equal to a circumferential length of the fixed electrode pole, the synthetic resin film including an electrode film on one face and ribs on the other face and entirely partitioned by the ribs into a plurality of diaphragm regions. The synthetic resin film is attached to an entire outer periphery of the fixed electrode pole such that the ribs are in contact with the outer periphery.

Abstract: A dynamic microphone that enables taking a long propagation path of a sound wave on a back side of a diaphragm, and by which unidirectivity can be obtained even at a low frequency. The dynamic microphone includes: a dynamic microphone unit; and an air chamber provided on a back side of a diaphragm of the dynamic microphone unit, wherein the air chamber is folded back to make a propagation path of a sound wave on the back side of the diaphragm long, a plurality of acoustic resistors is arranged in the air chamber at intervals to each other in a direction of the propagation path of a sound wave, and acoustic resistance values of the plurality of acoustic resistors become higher as the propagation path of a sound wave goes away from the diaphragm.

Abstract: A narrow directional microphone includes a unit case having a front end portion to which a microphone unit is mounted, and a side surface functioning as a grip, an acoustic tube formed of resin material in a tubular shape, covering the microphone unit, and attached to the front end portion of the unit case such that the microphone unit is positioned to an inner bottom portion of the acoustic tube, a piezoelectric film that is arranged in at least one part of the acoustic tube, and that generates a detection output based on a mechanical deformation of the acoustic tube, and an output signal processing unit including an attenuation circuit that attenuates an audio signal from the microphone unit with the detection output from the piezoelectric film and sends the attenuated audio signal to a signal output unit.

Abstract: Provided is a condenser microphone unit that prevents eccentricity as much as possible and achieves improvement of assembly accuracy. A condenser microphone unit including a diaphragm that vibrates upon receiving a sound wave and made by a plurality of configuration components that are assembled, the condenser microphone unit includes a base member including an opening portion to which the plurality of configuration components is attached, and an adjustment member having an outer diameter corresponding to a diameter of the opening portion, and mounted to a side surface of one or more components accommodated in the opening portion, of the plurality of configuration components. The adjustment member is a frame body exhibiting an annular shape and including a notch portion notched to have a pair of end portions, and is fixed in the opening portion in a state of being mounted to the side surface of the one or more components.

Abstract: A microphone is provided that prevents or reduces generation of noises caused by vibration from a grip body. A microphone includes a grip body having a shape of a cylinder, a head case attached to the grip body, a microphone unit disposed inside the head case, an internal cylinder to which the microphone unit is attached, and an elastic member configured to undergo shear deformation in the longitudinal direction of the grip body. The internal cylinder is disposed inside the grip body with the elastic member.

Abstract: A narrow-angle directional microphone includes: a microphone case; an acoustic tube fit in the microphone case with a gap between the acoustic tube and the microphone case; a microphone element arranged at one end side of the acoustic tube with a clearance that allows a front acoustic terminal and a rear acoustic terminal to communicate into each other between the microphone element and the microphone case; and an acoustic resistance body having elasticity positioned over between the one end side of the acoustic tube and the microphone element to block a passage between the front acoustic terminal and the rear acoustic terminal,whereby adjustments of a degree of compression of the acoustic resistance body are achieved by changes to an interval between the acoustic tube and the microphone element.

Abstract: A condenser type electroacoustic transducer includes a diaphragm, a fixed electrode having a surface facing the diaphragm, and a dielectric disposed in a partial region on the surface of the fixed electrode.

Abstract: In an electrodynamic acoustic transducer which uses a surface potential of an electret dielectric film as a polarization voltage, prevention of partial suctional adhesion of a diaphragm caused by variation in surface potential across the electret dielectric film is ensured in a simple way. In an electrodynamic acoustic transducer including a diaphragm and a fixed pole which are arranged with a predetermined interval so as to face each other, a facing surface of either one of the diaphragm and the fixed pole having an electret dielectric film, a surface of the electret dielectric film is divided into a plurality of segment regions, and a predetermined surface potential is given to each of the segment regions by a polarization processing unit.

Abstract: Provided is an impedance conversion circuit of a condenser microphone which includes a first electron tube operated in grounded-cathode mode to whose grid an output signal from a condenser microphone unit is inputted, and from whose plate a signal is outputted, a first emitter-follower circuit configured to receive a signal based on a plate output of the first electron tube and amplify a current, and a first feedback element configured to transmit a feedback signal from an emitter of a transistor configuring the first emitter-follower circuit to the grid of the first electron tube. And the impedance conversion circuit can achieve a wide dynamic range while using a voltage amplifier circuit with an electron tube at an initial stage.

Abstract: There is provided a boundary microphone inside which a unidirectional microphone unit is contained, the microphone including: a base plate; and a cover plate attached onto an upper face side thereof, wherein a thin and long tubular groove acting as an acoustic tube for making unidirectivity of the microphone unit a narrow directivity is formed on the base plate side, and therein, the microphone unit is contained. In order to prevent liquid from entering the tubular groove from the outside, between a peripheral edge part of the cover plate and the upper face of the base plate, a spacer that is composed of a water repellent thin film material and allows an inside of the tubular groove and outside air to communicate via acoustic resistance with a thin air layer is disposed so as to enclose an entire periphery of the tubular groove.

Abstract: A condenser microphone utilizes a PLL circuit which includes a phase shift oscillator having an RC network that uses an electrostatic capacitance of the condenser microphone unit varying upon reception of a sound pressure and a resistance value of a variable resistance element; a phase detection unit that compares phases of a fixed frequency signal from a reference signal oscillator and an oscillation output signal from the phase shift oscillator and outputs a phase difference signal corresponding to a phase difference; a loop filter that extracts a control signal when receiving the phase difference signal from the phase detection unit; and a driver circuit that changes a resistance value of the variable resistance element provided in the phase shift oscillator based on the control signal obtained from the loop filter. The control signal obtained from the loop filter of the PLL circuit is used as an audio output signal.

Abstract: The present invention provides a microphone device capable of preventing a breakdown of a signal processor, which is provided in a circuit case, processing signals from a microphone unit accommodated in a unit case, and preventing production of noise in a state the unit case is detached from the circuit case. A microphone device 1 includes a unit case 3 accommodating a microphone unit 31, a circuit case 4 accommodating an input terminal receiving signals from the microphone unit, and a signal processor processing the signals input to the input terminal, the unit case 3 being detachably fixed to the circuit case 4, and a detector (38, 44) detecting the attachment or detachment between the unit case and the circuit case. The detector grounds the input terminal in response to the detection of the detachment of the unit case from the circuit case.

Abstract: Provided is a condenser microphone including an audio-signal outputting printed circuit board and a rear case that are in stable electrical connection with each other. The condenser microphone includes a microphone unit 10, an audio-signal outputting printed circuit board 20 connected with the microphone unit 10, a rear case 30 having deep groove 31a, the deep groove 31a receiving the audio-signal outputting printed circuit board 20, a mounting groove 31b being formed on the outer periphery of the rear case 30, the mounting groove 31b receiving a mounting member 50, a fitting groove 21 being formed on the audio-signal outputting printed circuit board 20, the fitting groove 21 receiving the mounting member 50.