Abstract: A dynamic microphone unit includes a diaphragm vibrating upon receiving acoustic waves, a voice coil fixed to the diaphragm, vibrating together with the diaphragm, a magnetic circuit generating a magnetic field in a magnetic gap in which the voice coil is disposed, a rear air chamber formed behind the magnetic circuit, wherein holes for connecting a back side space of the diaphragm with the rear air chamber are formed in a member forming the magnetic circuit in order to reduce resonance and reduce peaks developing in frequency response characteristics, achieving uniformity of directivity.

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 handset microphone includes: a microphone unit, a first switch for turning on or off the output from the microphone unit, and a second switch for enabling or disabling the output from the microphone unit; the first and second switches have contacts operated by a magnetic field; the contact of the first switch is closed and short-circuits the output terminals while the first switch is being affected by the magnetic field; and the contact of the second switch is opened and disconnects one of the output terminals while the second switch is being affected by the magnetic field.

Abstract: A ribbon microphone includes a ribbon microphone unit; an acoustic box for mounting a rear acoustic terminal of the ribbon microphone unit; a detective microphone mounted in the acoustic box, the detective microphone detecting sound waves identical to sound waves guided to the rear acoustic terminal of the ribbon microphone unit; a speaker comprising a diaphragm, the speaker being assembled in the acoustic box and varying the pressure in the acoustic box in response to the driven diaphragm; and a drive unit for driving the speaker so as to cancel a variation in pressure in the acoustic box in response to signals detected by the detective microphone, the variation being caused by sound waves guided to the rear acoustic terminal. This configuration extracts an omnidirectional component without an acoustic tube to achieve a small high-sensitivity unidirectional ribbon microphone and a unidirectional converter for the ribbon microphone.

Abstract: A stereo microphone includes two unidirective mid units and a bidirective side unit, the side unit is a ribbon microphone unit including a ribbon diaphragm, the two mid units are disposed at two respective surfaces of the ribbon diaphragm of the side unit, and the mid units each have a sound collecting axis along a longitudinal direction of the ribbon diaphragm in the side unit.

Abstract: In an electro-acoustic transducer including a needle electrode and a counter electrode facing the needle electrode and inducing electric discharge between the needle electrode and the counter electrode for electro-acoustic conversion by an RF voltage applied across the needle electrode and the counter electrode, the counter electrode has a cylindrical surface surrounding plasma extending from the needle electrode and has a cutout in a part of the cylindrical surface. This configuration prevents a short circuit between the needle electrode and the counter electrode due to plasma.

Abstract: A condenser microphone includes a unit case that supports a condenser microphone unit, has an internal space in communication with a rear acoustic terminal of the microphone unit, and has an opening in a peripheral wall in communication with the internal space; a volume restrictor that reduces the volume of the internal space by partitioning the internal space; a circuit board disposed in the internal space and surrounded by the volume restrictor; and a rigid conductor that electrically connects a signal output terminal of the microphone unit and the circuit board. The circuit board intersects the center axis of the unit case. The rigid conductor is supported such that the rigid conductor slides along the volume restrictor. An elastic conductor is compressed between the rigid conductor and the circuit board or between the rigid conductor and the signal output terminal of the microphone unit.

Abstract: A condenser microphone includes a condenser microphone unit and a piezoelectric element. The piezoelectric element is disposed so as to generate piezoelectric signals in response to vibration causing the unit to generate vibratory noise signals. The piezoelectric signals are inputted through a low-pass filter and a level adjuster circuit to the unit to drive a diaphragm of the unit. The vibratory noise signals generated by the vibration in the unit are canceled with the piezoelectric signals generated by the piezoelectric element.

Abstract: A condenser microphone includes multiple condenser microphone units. Each unit includes an impedance converter. The condenser microphone units are connected in series such that outputs of the impedance converter in one of the condenser microphone units drive another of the condenser microphone units. A polarization voltage is accumulated to a DC voltage supplied from a DC voltage supply through a voltage adjuster to be applied to one of a diaphragm and a fixed electrode, and a voltage applied to the one of the diaphragm and the fixed electrode is adjusted by the voltage adjuster.

Abstract: To provide a noise reduction transmitter which can secure clarity of sounds collected in very noisy environments and maintain a quality of sounds without devising a noise insulation cover particularly. A transmission microphone 7 is arranged inside a noise insulation cover 2 worn on and covering at least a user's 1 mouth. A noise detection microphone 9 which detects external noises is arranged outside the noise insulation cover, and a noise component cancellation circuit 11 is provided which generates a noise component cancellation signal based on an output signal from the noise detection microphone. An electroacoustic transducer 8 is arranged in the noise insulation cover to reproduce a noise component cancellation sound based on an output signal from the noise component cancellation circuit 11.

Abstract: To stably obtain high acoustic resistance required for pressure equalization in a non-directional condenser microphone unit. A diaphragm 8 whose circumferential edge is attached to a diaphragm holder 4 and a fixed electrode 6 made of a metal material and arranged to face the diaphragm at a predetermined interval through an electrically insulating spacer 5 are provided, and the rear space of the above-mentioned diaphragm is closed to constitute the non-directional condenser microphone unit. A blind groove 16a is formed by an etching process at a portion which is in contact with the spacer 5 and in the fixed electrode 6 so that the rear space between the diaphragm and the fixed electrode may communicate with the outside, and a communication part formed between the groove 16a and the spacer 5 may be used as acoustic resistance for pressure equalization.

Abstract: A unidirective condenser microphone unit includes a diaphragm; a fixed electrode facing the diaphragm with a gap and defining a capacitor together with the diaphragm; an insulating spacer disposed adjacent to the rear surface of the fixed electrode and supporting the fixed electrode; an acoustic resistor disposed in an air chamber defined by the front surface of the insulating spacer and the fixed electrode; a unit case, a front acoustic terminal; and a rear acoustic terminal. The insulating spacer has a protrusion projecting toward the fixed electrode with a gap, and the protrusion is fixed to the surface of the fixed electrode with fixing material.

Abstract: A condenser microphone unit includes a diaphragm; a fixed electrode defining a capacitor together with the diagram; a cylindrical electrode having a first end and a second end, the first end being fitted to the periphery of the fixed electrode; a circuit board in contact with a second end of the cylindrical electrode, the circuit board being electrically connected to the cylindrical electrode; a unit casing accommodating the diaphragm, the fixed electrode, the cylindrical electrode, and the circuit board; and a hollow insulating air chamber provided between the internal peripheral surface of the unit casing and the external peripheral surface of the cylindrical electrode.

Abstract: A condenser microphone which prevents a directional axis from varying depending on a sound source frequency is provided. The condenser microphone includes a first reflector member 2 provided below the microphone unit 17 and covering an electronic circuit substrate 19 and a second reflector member 3 formed in the same shape as the first reflector member and provided above the microphone unit, the first reflector member and the second reflector member being disposed symmetrically with respect to the microphone unit.

Abstract: A dynamic microphone unit includes: a diaphragm that vibrates in response to received sound waves; a voice coil that is fixed to the diaphragm and vibrates together with the diaphragm; a magnetic circuit that generates a magnetic field in a magnetic gap, the voice coil being disposed in the magnetic gap; a resonator that is disposed adjacent to the obverse of the diaphragm; and a noise canceling coil that is fixed to a surface of the resonator so as to face a position of fixing the voice coil, the surface facing the diaphragm. The noise canceling coil is connected in series with the voice coil and has a winding direction different from that of the voice coil.

Abstract: A phantom power circuit has a detection circuit and a limiting circuit, the detection circuit detecting a pulse current generated in association with connection or disconnection of a condenser microphone, the limiting circuit limiting the output of the condenser microphone. The detection circuit detects a pulse current generated between input terminals of the condenser microphone. The limiting circuit reduces the output from the condenser microphone when the detection circuit detects the pulse current.

Abstract: A microphone holder is provided that allows a microphone to be attached and detached by a one-touch operation and to be securely held. A first and a second magnet 77a and 72b are provided at positions where a holding frame 5 and a clamp arm 6 overlap with each other such that different poles are opposed to each other. The magnets are magnetically attached to each other to lock the movement.

Abstract: A microphone includes a microphone unit having a diaphragm, a fixed electrode and a FET as an impedance converter; a plug outputting audio signals output from the microphone unit; and a jack into which audio signals inputted in the microphone unit are inputted. While the plug of the other microphone is inserted in the jack of the microphone, the audio signals output from the other microphone unit are added to the audio signals output from the microphone unit and are output.

Abstract: A back air room of a microphone unit can be enlarged and a model with a sound signal output switch can easily be diverted to a switchless model. A reed switch 16 is used as the sound signal output switch which turns on or off the sound signal from a microphone unit 1. This reed switch is disposed at an output connector 11 portion at an rear end of a microphone case 6. It is arranged that a magnet 22 is disposed at a connector cover 21 which surrounds an output connector and relative movement of the connector cover with respect to the output connector allows on/off operation. Thus, by removing the connector cover 21, it is possible to provide the microphone as a switchless model which always outputs the sound signal from the microphone unit 1.

Abstract: A microphone unit has a diaphragm vibrating in response to sound waves; a unit casing accommodating the diaphragm; and a connecting path connecting a front acoustic terminal and a rear acoustic terminal. The unit casing has a small-diameter internal periphery defining the front acoustic terminal; a large-diameter internal periphery accommodating built-in components including the diaphragm; and a shoulder provided between the small-diameter internal periphery and the large-diameter internal periphery and positioning the built-in components. The unit casing has a groove in an axial direction provided in the large-diameter internal periphery and a groove in a radial direction provided in the shoulder and being in communication with the groove in the axial direction. The groove in the axial direction and the groove in the radial direction configure the connecting path.