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 boundary microphone that can reduce the change in its directional property caused by change of a sound collection axis of a microphone unit is provided. The boundary microphone includes a unidirectional microphone unit, a cylindrical unit holding member having a unit accommodating pocket in its peripheral surface to accommodate the unidirectional microphone unit, and a boundary plate to which top face the unit holding member is attached so as to rotate about its axis. When the unidirectional microphone unit is held in the unit holding member, a front acoustic terminal is positioned to face the outside of the peripheral surface of the unit holding member, the sound collection axis intersects the axis of a hollow of the unit holding member, and a rear acoustic terminal communicates with the outside at both side ends of the hollow via the hollow of the unit holding member.

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 stereo boundary microphone includes a boundary plate, a case body attached to the boundary plate and having an elongate shape including left and right grooves provided in opposite sides and extending along the longitudinal direction, first and second side walls covering the grooves included in the case body by predetermined distances to form left and right acoustic passages, and first and second microphones contained in tail end portions of the acoustic passages so as directional axes of the first and second microphones to be parallel. An opening communicating with the tail end portion of the case body is provided and services as a rear acoustic terminal to be used by both the first and second microphones. Front ends of the acoustic passages formed by the side walls serve as left and right front acoustic terminals of the first and second microphones.

Abstract: A variable directional microphone includes a unidirectional microphone unit having a front acoustic terminal and a rear acoustic terminal; an acoustic tube which accommodates the microphone unit therein and having a plurality of acoustic resistance openings in a circumferential wall thereof; a supporting member mounted within the acoustic tube to be movable along an axis of the acoustic tube and supporting the microphone unit, the supporting member having a predetermined acoustic resistance and allowing transmission of sound waves; and further includes a gap formed between an outer circumferential wall of the microphone unit and an inner circumferential wall of the acoustic tube for providing communication between the front acoustic terminal and the rear acoustic terminal. Directionality of the variable directional microphone changes depending on the position of the microphone unit in the acoustic tube.

Abstract: A condenser microphone unit is provided that can flatten a frequency response in a high frequency band. The condenser microphone unit includes a unit case having an acoustic-wave entering hole, and a diaphragm accommodated in the unit case. The diaphragm is configured to vibrate in response to acoustic waves from the acoustic-wave entering hole. In the condenser microphone unit, an acoustic resistor is disposed between the acoustic-wave entering hole and the diaphragm. The acoustic resistor includes two elastic members in pressure contact with each other. At least one of the two elastic members is curved in a convex shape before contacting the other of the two elastic members by the pressure contact. A convex surface of one of the two elastic members is a surface that comes in pressure contact with the other elastic member.

Abstract: The electret condenser microphone according to the present invention includes an electret condenser microphone unit including a diaphragm and a fixed pole disposed opposite to the diaphragm; and a three-pin plug including a hot terminal and a cold terminal and being capable of producing a balanced output, wherein each of the hot terminal and the cold terminal is coupled to an FET that functions as an impedance converter a gate terminal of one of the FETs is coupled to the diaphragm, a gate terminal of the other of the FETs is coupled to the fixed pole, and the gate terminal of the FET coupled to the cold terminal is AC-grounded.

Abstract: A connector for a microphone and a microphone are provided that can prevent loose connections to a microphone stand. The connector for the microphone is to be inserted into a connector support hole of a microphone stand. The connector includes pins to be electrically connected to the microphone stand, a connector body accommodating the pins, a sleeve disposed on the outer circumferential surface of the connector body, and an elastic member for biasing the sleeve toward the rear end of the connector body. The sleeve has an insertion portion to be inserted into a space between the connector body and the connector support hole.

Abstract: A dynamic headphone unit includes a diaphragm to which a voice coil is fixed, a permanent magnet, a pole piece disposed adjacent one of the magnetic poles of the permanent magnet, and a yoke disposed adjacent the other magnetic pole of the permanent magnet. The pole piece and the yoke define a magnetic gap therebetween, and the voice coil is vibratably supported by the diaphragm in the magnetic gap. The voice coil includes a lead line for transmitting signal current. The lead line is bonded to the inner surface of a peripheral dome of the diaphragm with a pressure-sensitive adhesive.

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 stereo microphone includes an omnidirectional microphone unit, a bidirectional side-channel microphone unit arranged to be perpendicular to a direction of a sound collecting axis outside the omnidirectional microphone unit, a right-channel microphone unit arranged to form a predetermined angle with respect to the side-channel microphone unit on a plane including the sound collecting axis outside the omnidirectional microphone unit, and a left-channel microphone unit arranged to forma predetermined angle with respect to the side-channel microphone unit and the right-channel microphone unit on the plane including the sound collecting axis outside the omnidirectional microphone unit.

Abstract: A microphone is provided that ensures the electrical connection between a unit case and an audio-signal output circuit board. The microphone includes a unit case 10 having a shape of a hollow cylinder with a closed end and accommodating an electroacoustic transducer 20, an audio-signal output circuit board 40 connected to the electroacoustic transducer, and a microphone case accommodating the unit case and the audio-signal output circuit board, wherein the audio-signal output circuit board has a receiver 41 disposed on a portion of the peripheral edge of the audio-signal output circuit board, and an open end 11 of the unit case comes into contact with the receiver and is positioned when the unit case and the audio-signal output circuit board are accommodated in the microphone case.

Abstract: A boundary microphone is provided that does not generate spark discharge during an operation of a switch. The boundary microphone includes a microphone unit 6, and a switching unit (a button 4, a tube 9, a detector 10, a comparator, and a switching circuit) that switches turning-on or turning-off of output signals from the microphone unit 6, wherein the switching unit (the button 4, the tube 9, the detector 10, the comparator, and the switching circuit) includes an air chamber 9 and a controller that controls the turning-on or turning-off based on the air pressure inside the air chamber 9.

Abstract: Excellent narrow-angle directivity is obtained by causing a microphone case main body to function as an acoustic tube, reducing a weight of a microphone, and suppressing leakage of sound waves from an inside of the acoustic tube to an outside. An acoustic tube microphone case includes a microphone case main body made of a metal tube having a plurality of openings formed in a peripheral surface, and acoustic resistance materials formed in a rectangular sheet manner, cylindrically rounded such that both right and left ends are mutually in contact, and arranged along an inner peripheral surface of the microphone case main body. A plurality of the acoustic resistance materials is layered, and at least the innermost acoustic resistance material applies a force in a developing direction by an elastic force thereof, and presses the outside acoustic resistance materials against the inner peripheral surface of the microphone case main body.

Abstract: A microphone includes a microphone unit that converts a sound into an electrical signal. A tubular housing houses the microphone unit and includes a rear opening portion in a side surface. A step portion surrounds the rear opening portion in an inner surface of the housing. A plate-like shielding member is attached to the step portion from an inner surface side of the housing, and a circuit board housed in the housing in contact with the shielding member includes a ground pattern its side surface and in a contact position between the circuit board and the shielding member.

Abstract: A condenser microphone includes a condenser microphone unit having a diaphragm and a fixed electrode disposed opposite to the diaphragm; a field effect transistor serving as an impedance converter; and a transistor to generate operational power for the field effect transistor; wherein the field effect transistor comprises a gate, a source and a drain, the gate is connected to the fixed electrode or the diaphragm, the diaphragm disposed opposite to the fixed electrode connected to the gate or the fixed electrode facing the diaphragm connected to the gate is grounded; the source is connected to a base of the transistor; the drain is connected to an emitter of the transistor; and a resistor establishing a base potential of the transistor is disposed between the base of the transistor and a ground.

Abstract: A condenser microphone outputs a signal resistive to distortion caused by an excess input without a variation in signal-to-noise ratio. The microphone includes a first condenser microphone unit and a second condenser microphone unit that generate output signals having phases opposite to each other; and a twin variable resistor connected to an output terminal of each of the first and second condenser microphone units. In the microphone, the output signal of the first unit is combined with the output signal of the second unit in a first variable resistor included in the twin variable resistor and the composite signal is applied to an input of the first unit, and the output signal of the first unit is combined with the output signal of the second unit in a second variable resistor included in the twin variable resistor and the composite signal is applied to an input of the second unit.

Abstract: A connector of a microphone includes a cylindrical connector case 1 having openings at both ends and a projection 10 on an inner face thereof; two substrates 11 and 12 having shapes fittable to the inner face of the cylindrical connector case 1, the substrates 11 and 12 facing each other across the projection 10 in the cylindrical connector case 1; and a connector pin 2 extending through the substrates 11 and 12 in the cylindrical connector case 1, having a contact 21 that is electrically connected to electronic parts 16 mounted on the substrates 11 and 12, and having a caulked portion 23 fixed to one of the substrates 11 and 12 on an opposite side to the contact 21.

Abstract: A microphone device includes an audio signal output circuit that balanced-outputs, through a balanced transmission line, an audio signal output from a condenser microphone unit, a balanced output terminal including a hot terminal, a cold terminal, and a ground terminal connected to the balanced transmission line, a power supply circuit that supplies a phantom power supply to the audio output circuit from the balanced output terminal through the balanced transmission line, and a display circuit including light emitting elements that perform lighting and non-lighting according to an operation of a manual switch, and the display circuit includes constant current elements that generate a constant current through the balanced transmission line, a constant voltage element connected to the constant current elements and which generates a constant voltage, and light emitting elements connected to the constant current elements, and to which the constant voltage by the constant voltage element is applied.

Abstract: An acoustic tube attaching unit that attaches an acoustic tube to a side of a main body case where a microphone unit is mounted. The acoustic tube attaching unit includes first and second elastic members lying between a fixing member and a washer, and bolts that tight the fixing member and the washer in an axial direction. A peripheral edge surface of the first elastic member is formed in a linear manner, and a peripheral edge surface of the second elastic member is formed in a recessed surface manner, so that the peripheral edge surface of the first elastic member protrudes in an outer peripheral direction by elastic deformation by the tightening of the bolts. The acoustic tube is attached to the main body case side by fixing action to an inner wall of the acoustic tube by the protrusion of the first elastic member in the outer peripheral direction.