Abstract: A microphone includes a polar piece contacting with a first magnetic pole of a first permanent magnet, a yoke body annularly arranged around the polar piece through a magnetic gap G with a predetermined width, a magnetic circuit unit including a tail yoke connected to the yoke body and contacting with a second magnetic pole of the first permanent magnet, and a diaphragm unit provided with a voice coil arranged to vibrate in the magnetic gap. The second magnetic pole of the first permanent magnet contacts with one side of the tail yoke, a first magnetic pole of the second permanent magnet is disposed to contact with other side of the tail yoke, a magnetic path is produced between the second magnetic pole of the second permanent magnet and the yoke body, and the first permanent magnet and the second permanent magnet are polarized in the same sense.

Abstract: Housings on the right/left of the noise cancellation headphone, where a speaker unit is incorporated, are connected to each other with a headband, and a battery receiving portion is provided on a side surface of at least one of the right and left housings. The battery receiving mechanism includes: a battery receiving portion provided in the side surface of the housing; a battery lid opening and closing the battery receiving portion; and a flexible connecting member preventing the battery lid from dropping off from the housing in a state where the battery lid opens the battery receiving portion. The housing and the battery lid each include an engagement part which engages with each other by pushing in the battery lid in a direction intersecting with the side surface of the housing, and the battery lid occupies a part of the side surface of the housing.

Abstract: Provided is a narrow-angle directional microphone in which a microphone unit is attached to an acoustic tube, the acoustic tube is accommodated a microphone case and which prevents the rattling of components provided in the microphone case and has high mechanical strength. A narrow-angle directional microphone 1 includes a microphone unit 2, an acoustic tube 3 that has an opening formed in a circumferential wall along an axis direction and a rear end to which the microphone unit is connected, a cylindrical microphone case 4 that accommodates the acoustic tube, and fixing means 3a, 4a, 10, and 20a that fix the acoustic tube in the microphone case, with stress being applied to the acoustic tube in the microphone case in the axis direction from the leading end side of the acoustic tube using the rear end of the acoustic tube as a fulcrum.

Abstract: A ribbon microphone circuit includes a ribbon microphone unit; a step-up transformer; buffer amplifier circuits connected to a secondary winding of the step-up transformer; an external power supply circuit as a power source for driving the buffer amplifier circuits; and a switch circuit including photo-relays having lights that are turned on while the external power source is being supplied and having contacts operating depending on states of the respective lights, wherein signals output from the ribbon microphone unit are sent through the buffer amplifier circuits while the external power source is being supplied, and sent without passing through the buffer amplifier circuits while the external power source is being not supplied.

Abstract: A microphone adapter is attachable to a microphone including a microphone unit and a casing having a front sound terminal and a back sound terminal. The microphone adapter has a bottom having a hole through which the casing of the microphone extends and a cylindrical peripheral wall integrated with the bottom, having an open end opposite to the bottom, and covering the periphery of the back sound terminal. The cylindrical peripheral wall has an internal diameter larger than the external diameter of the casing of the microphone so as to define a space between the cylindrical peripheral wall and the external peripheral surface of the casing of the microphone extending through the hole, and extends from the bottom at least to a position of the front sound terminal in a sound collection axis direction.

Abstract: Noise canceling headphones designed so that external noise coming from all directions can be effectively concerned by means of a canceling sound before being heard by a user. These feed-forward noise canceling headphones use noise canceling headphones (10), each of which comprises an air chamber (8) formed from a space that is sealed by a member covering the outer circumference of the housing and provided more outward than a front air chamber (7), and wherein the sound-wave introducing part of a microphone (2) is inside the air chamber (8).

Abstract: A handheld condenser microphone is provided with a condenser microphone unit having two unidirectional condenser elements. A conductive fabric 221 is put between a lock ring 213 and the second condenser element 10b, when an acoustic-electric transducer 220 is fixed inside a unit case 210 by fastening force of the lock ring 213.

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 first diaphragm FD and a second diaphragm RD are respectively arranged across a fixed electrode BP at both sides to constitute the variable directivity condenser microphone. A microphone body 1 includes a vacuum tube Q1 for impedance converting an audio signal obtained at the fixed electrode, and a connector 2 provided with a hot side connector terminal and a cold side connector terminal through which the audio signal that is impedance converted by the vacuum tube is outputted in parallel. A means for supplying a polarization voltage applied to the second diaphragm RD from an external power supply circuit 3 is arranged such that the hot side connector terminal and the cold side connector terminal are used as a forward conductor and a ground connector terminal for the microphone body arranged at the connector is used as a return conductor.

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: 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 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 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.