JP4974690B2 - Ribbon microphone unit and ribbon microphone - Google Patents

Description

  The present invention relates to a ribbon microphone unit using a plurality of movable diaphragms (hereinafter referred to as “ribbon-shaped diaphragms”) formed in a ribbon shape, and a ribbon microphone including the ribbon microphone unit.

  One type of magnetoelectric microphone that collects sound by using electromotive force generated by vibration of a diaphragm is a ribbon microphone that uses a ribbon diaphragm. This ribbon microphone has been avoided for a long time because of its low sensitivity. Has attracted attention in the field.

As shown in FIG. 7, the ribbon microphone includes a ribbon microphone unit including a pair of magnets 104 and 104 that form a magnetic field and a ribbon diaphragm 103 disposed in the magnetic field of these magnets 104 as main components. The basic configuration is to provide.
Further, in the ribbon microphone unit, the ribbon diaphragm is loosely stretched while an appropriate tension is applied by pressing one end side and the other end side in the length direction. For this reason, a ribbon microphone equipped with such a ribbon microphone unit has a light vibration system and is easy to move, and is vulnerable to noise such as human breath and external mechanical vibration. Can be picked up, that is, it has the advantage of having a wide frequency band.
In the ribbon microphone, when the ribbon diaphragm receives a sound wave and vibrates in a magnetic field, electricity flows through the ribbon diaphragm and the sound wave is converted into an electric signal.

  Such a ribbon microphone is designed to increase the magnetic flux density between the magnetic poles in order to increase sensitivity. However, in a ribbon microphone, a signal (electricity) induced from the vibration of a ribbon diaphragm such as an aluminum foil is very weak. For this reason, the output level is low because the impedance is low and the conversion efficiency from voice to current is low. Therefore, it is necessary to step up the signal level to a level that can be handled by the amplifier, for example, up to 1: 50-70 in the step-up ratio. Usually, a step-up transformer for impedance matching is required to step up this signal.

In order to increase sensitivity, a ribbon diaphragm unit that uses a plurality of ribbon diaphragms has also been proposed. For example, as shown in FIG. 8, ribbon-shaped diaphragms 103 </ b> A and 103 </ b> B are disposed in front and rear between a pair of magnets 104 and 104, respectively, so that the vibration direction is cut off between the magnets 104 and 104. A ribbon microphone unit can be obtained by arranging in the above.
There are the following two connection modes of the two ribbon diaphragms arranged in this way.
One is a method of increasing the output voltage by connecting two ribbon-shaped diaphragms 103A and 103B in series as shown in FIG. The other is a method of reducing impedance by connecting two ribbon diaphragms 103A and 103B in parallel as shown in FIG. Note that reference numeral 150 in FIGS. 9 and 10 indicates a step-up transformer.

In addition, as shown in FIG. 11, one end of a ribbon-shaped diaphragm 103A disposed between a pair of magnets 104, 104 is electrically connected to a yoke 102 constituting a magnetic pole, and the yoke is used as a conductor. Has also been proposed.
Further, there has also been proposed a microphone that has four ribbon-shaped diaphragms and outputs the outputs of the respective ribbon-shaped diaphragms individually or in combination (see, for example, Patent Document 1).

However, in the case of the series connection as shown in FIG. 9, wiring for electrically connecting the respective ribbon diaphragms arranged between the pair of magnets at the front and rear is necessary. In this case, since the impedance of the ribbon diaphragm itself is low, the electrical wiring for connection is required to be thick and have low electrical resistance. Therefore, it is necessary to pay attention not to increase the connection resistance in connection, which is troublesome in structure.
On the other hand, in the case of the parallel connection as shown in FIG. 10, the impedance of the microphone unit configured using the ribbon diaphragm can be reduced to about half. However, in order to increase the output voltage, it is necessary to increase the step-up ratio of the transformer. Therefore, when the step-up ratio of the transformer is increased, there is a problem that the frequency response is deteriorated.
Further, in the case of the connection mode as shown in FIG. 11, since the yoke is generally fixed to the outer casing, the operation of the ribbon diaphragm is unbalanced. As a result, noise is easily generated by an external dielectric magnetic field. In this case, there is a method in which the yoke is not electrically connected to the outer casing. However, the potential of the yoke is not determined and noise is likely to be generated. Therefore, the yoke is generally connected to ground.
Further, the technique described in Patent Document 1 does not increase the sensitivity of the microphone and increase the output signal.
Japanese Utility Model Publication No. 47-27831

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a ribbon microphone unit and a ribbon microphone having high sensitivity and a large output signal using a ribbon diaphragm.

A ribbon microphone unit according to the present invention is a ribbon microphone unit having a structure in which a ribbon-shaped diaphragm is arranged in the magnetic field of a pair of magnets that form a magnetic field. The ribbon microphone unit has a support made of a magnetic material, on one side of the support. A pair of attached first magnets, a first ribbon diaphragm arranged in the magnetic field of the first magnet, a pair of second magnets attached to the other surface side of the support, and the second magnet with second ribbon diaphragm disposed within the magnetic field of at least, one end side of the first ribbon diaphragm, and one end side of the second ribbon diaphragm is, through the support The main feature is that they are electrically connected.

The ribbon microphone unit of the present invention includes a first ribbon-type diaphragm disposed in a magnetic field formed by a pair of first magnets, and a second ribbon disposed in a magnetic field formed by a pair of second magnets. The other end of the shaped diaphragm is electrically connected via a support made of a magnetic material.
Therefore, the first ribbon diaphragm and the second ribbon diaphragm are connected in series, and the sensitivity of the ribbon microphone can be increased and the output voltage can be increased by the two ribbon diaphragms. In addition, the two ribbon diaphragms that are connected in series and vibrate in the same phase operate in a balanced manner, and the output audio signal can be a push-pull signal.
Therefore, it is possible to provide a ribbon microphone unit and a ribbon microphone having high sensitivity and a large output signal using the ribbon diaphragm.

Hereinafter, embodiments of a ribbon microphone unit according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a front view showing an example of a ribbon microphone unit according to the present invention. 2 is a vertical cross-sectional view taken along the line I-I indicated by the one-point difference line in FIG. 1, and FIG. 3 is a cross-sectional view taken along the line II-II indicated by the one-point difference line in FIG. is there.
The ribbon microphone unit 1 of the present embodiment has a structure in which a ribbon-shaped diaphragm is arranged in the magnetic field of a pair of magnets that form a magnetic field, and has a rectangular window hole as shown in FIGS. A pair of first magnets 4A, 4A attached to the one surface 2a side of the support 2, and a first ribbon diaphragm 3A disposed in the magnetic field of the first magnet 4A, A pair of second magnets 4B, 4B attached to the other surface 2b side of the support 2 and at least a second ribbon diaphragm 3B arranged in the magnetic field of the second magnet 4B are provided.

In the ribbon microphone unit 1, one end 33 a side of the first ribbon diaphragm 3 </ b> A and one end 33 b side of the second ribbon diaphragm 3 </ b> B are electrically connected via the support 2. It is characterized by.
As a result, the sensitivity is enhanced by the two ribbon-shaped diaphragms 3A and 3B connected, and the output level of the audio signal output by the serial connection can be increased to obtain a push-pull signal. In addition, it is not necessary to increase (increase) the step-up ratio in the step-up transformer so that the frequency response does not deteriorate. Further, since the ribbon diaphragms 3A and 3B that vibrate in the same phase operate in a balanced manner, noise due to an externally induced magnetic field can be hardly generated.

  The support body 2 is a so-called yoke, and lowers the magnetic resistance of the magnetic circuit including the first magnets 4A, 4A and the second magnets 4B, 4B, and between the first magnets 4A, 4A and the second magnet 4B. , 4B to increase the magnetic flux density. Examples of the material of the support 2 include soft magnetic materials such as iron, blunt iron, silicon iron, and amorphous.

  The first ribbon diaphragm 3 </ b> A and the second ribbon diaphragm 3 </ b> B are movable diaphragms formed in a ribbon shape, and a thin conductor having a thickness of several microns that is cut into an elongated shape is used. Examples of the material for the ribbon diaphragm include aluminum foil. This aluminum is suitable as a ribbon-type diaphragm for a ribbon microphone because of its good conductivity and low specific gravity compared to other metal materials.

The first ribbon diaphragm 3 </ b> A and the second ribbon diaphragm 3 </ b> B have conductive spacers 8 stacked on both sides of the support 2 with the support 2 sandwiched between the ends 33 a and 33 b. Further, the presser member 6 that is overlaid on the upper surface 8 is further fastened by a screw 16 to be fixed to the support body 2. Therefore, the connecting portion between the first ribbon diaphragm 3 </ b> A and the second ribbon diaphragm 3 </ b> B is electrically connected via the support 2. The other ends 34a and 34b of the first ribbon diaphragm 3A and the second ribbon diaphragm 3B are electrically insulating spacers 9 stacked on both surfaces of the support 2 with the support 2 sandwiched therebetween, respectively. , 9, and the presser member 7 stacked from above is fixed to the support 2 by being tightened by screws 17.
This eliminates the need for electrical wiring for relaying the ribbon-shaped diaphragms, and enables reliable electrical connection, low impedance, and no generation of noise.

Since the holding member 7 is made of a conductive member, a part of the holding member 7 can serve as the output terminal portions 7a and 7b. In FIG. 1, the presser member 7 is formed in a T-shape, and the tip portions hanging from the center are output terminal portions 7a and 7b. The output terminal portions 7a and 7b output audio signals generated by the first ribbon diaphragm 3A or the second ribbon diaphragm 3B, and are electrically connected to an impedance matching step-up transformer 50 described later. Connected.
As a result, it is possible to easily take out an audio signal generated by the first ribbon diaphragm 3A or the second ribbon diaphragm 3B and to easily connect the step-up transformer 50.

When the first ribbon diaphragm 3A and the second ribbon diaphragm 3B are thin conductor plates such as aluminum foil, it is necessary to lower the resonance frequency. Therefore, generally, a conductor thin plate formed in a ribbon shape is pressed against a gear-shaped molded member, and is bent into a bellows shape along the short direction, thereby increasing the substantial length. However, in the ribbon diaphragm having such a structure, when a strong impact or wind pressure is applied, the ribbon diaphragm is plastically deformed (stretched), which is not preferable. In particular, the central part, which is the main part of the ribbon diaphragm, is easily extended. Therefore, as shown in FIG. 4, the end portions 31, 31 in the length direction of the ribbon diaphragm 3 (3A, 3B) are bent in a bellows shape along the short direction (width direction), The central portion 32, which is the main portion, may be bent in a bellows shape along the length direction.
As a result, both end portions 31 and 31 of the ribbon diaphragm 3 (3A and 3B) can receive a sound wave and easily vibrate in a magnetic field, and the main part of the ribbon diaphragm 3 (3A and 3B). The possibility that the part 32 is plastically deformed can be suppressed.

The first magnet 4A and the second magnet 4B are permanent magnets respectively joined to the one surface 2a side and the other surface 2b side of the support 2. That is, the support body 2 is sandwiched between the first magnet 4A and the second magnet 4B. The first magnet 4A and the second magnet 4B form a magnetic circuit as shown in FIG. 5, and a magnetic field is formed in a space where the first magnet 4A and the second magnet 4B face each other.
In FIG. 5, for example, the magnetism emitted from the magnet extends from one side of the first magnet 4 </ b> A to the other, reaches the second magnet 4 </ b> B through the support body 2, and is supported again from one side of the second magnet 4 </ b> B to the other. Return to one of the first magnets 4A through the body 2. Accordingly, a magnetic field is formed from one to the other of the first magnet 4A and from one to the other of the second magnet 4B, and the ribbon diaphragms 3A and 3B are arranged in parallel to the magnetic field direction. Ribbon-shaped diaphragms 3A and 3B, when receiving a sound wave, vibrate in a direction across the magnetic field and generate an electrical signal corresponding to the sound wave.

The support 2 preferably has a grounding terminal portion 5. The ground terminal portion 5 is connected to, for example, the center tap of the primary winding of the step-up transformer 50. Since the current flowing through the grounding terminal portion 5 is small and there is no problem even if the electrical resistance of the wiring connecting the grounding terminal portion 5 and the primary winding of the step-up transformer 50 is high, fine wiring may be used.
As a result, the support 2 can be electrically connected to the ground so that noise is hardly generated by an externally induced magnetic field, and wiring can be easily routed.

The support 2 may have a horseshoe shape or the like, but as described above, the support 2 is preferably a frame having a window-like hole. Thereby, the ground terminal portion 5 can be formed so as to extend from the end edge portion of the support 2.
The grounding terminal portion 5 is formed in the vicinity of the edge portion of the support 2 to which the other end 34a, 34b side of the ribbon diaphragms 3A, 3B is attached and fixed, so that it is close to the output terminal portions 7a, 7b. Can be formed. Therefore, the output terminal portions 7a and 7b are connected to the respective terminals of the primary winding of the step-up transformer 50, and the ground terminal portion 5 is connected to the center tap of the primary winding of the step-up transformer 50 without extending the electrical wiring for a long time. I can do it.
Further, since the support body 2 is a frame body, the one end 33a, 33b side and the other end 34a, 34b side of the first ribbon-type diaphragm 3A and the second ribbon-type diaphragm 3B are stably attached to the support body 2. Can be fixed.

The first ribbon diaphragm 3A and / or the second ribbon diaphragm 3B is connected to the support 2 via the spacer 8 on one end 33a, 33b side and the spacer 9 on the other end 34a, 34b side. It should be attached.
As a result, each of the ribbon diaphragms 3A and 3B protrudes outward from the surface of the support 2 by the thickness of the spacers 8 and 9. Therefore, the ribbon diaphragms 3A and 3B can be reliably arranged in the magnetic field formed by the magnets 4A and 4B arranged on the same support 2.

The spacers 8 and 9 are thinner than the first magnet 4A and / or the second magnet 4B. That is, as shown in FIG. 3, it is assumed that the thickness t1 of the spacer 8 is smaller than the thickness t2 of the first magnet 4A and the thickness t3 of the second magnet 4B, and has a relationship of t1 <t2, t3. 3 shows only the spacer 8 attached to one end side of each of the ribbon diaphragms 3A and 3B, the same applies to the spacer 9.
Thereby, each ribbon-shaped diaphragm 3A, 3B is located inward from the virtual surface that connects the outer surfaces of the magnets 4A, 4A and the virtual surface that connects the outer surfaces of the magnets 4B, 4B. Therefore, the ribbon diaphragms 3A and 3B can be reliably arranged in the magnetic field generated by the magnets 4A and 4B.

FIG. 6 shows an example of the electrical wiring configuration in the ribbon microphone unit 1 configured as described above.
In FIG. 6, the step-up transformer 50 has a center tap T on the primary side. Therefore, the output terminal portions 7a and 7b can be connected to the respective primary terminals of the transformer, and the ground terminal portion 5 can be connected to the center tap T thereof.
The secondary side of the step-up transformer 50 is connected to a broadcast audio microphone input terminal (not shown) of the mixer, for example, via a microphone cable (not shown).

  And, by incorporating the ribbon microphone unit 1 configured in this way into a microphone case having a head case made of metal mesh or punching metal that takes in sound waves and protects internal components, the sensitivity is high, A ribbon microphone having a large output signal can be provided.

It is a front view which shows the Example of the ribbon microphone unit which concerns on this invention. It is a longitudinal cross-sectional view along the II line | wire shown in FIG. It is a cross-sectional view along the II-II line shown in FIG. It is a perspective view which shows the example of the ribbon-type diaphragm applicable to the ribbon microphone unit which concerns on this invention. It is a cross-sectional view explaining the magnetic path in the Example of the said ribbon microphone unit. It is a wiring diagram which shows the example of the electrical wiring applied to the Example of the said ribbon microphone unit. It is a perspective view explaining simply an example of the conventional ribbon microphone unit. It is a top view which shows simply the other example of the conventional ribbon microphone unit. It is the schematic explaining the connection method of the ribbon-shaped diaphragm in the conventional ribbon microphone unit. It is the schematic explaining the other connection method of the ribbon-shaped diaphragm in the said ribbon microphone unit. It is a front view which shows the other example of the conventional ribbon microphone unit.

Explanation of symbols

1 Ribbon microphone unit 2 Support (yoke)
3A 1st ribbon type diaphragm 3B 2nd ribbon type diaphragm 4A 1st magnet 4B 2nd magnet 5 Grounding terminal part 6, 7 Holding member 7a, 7b Output terminal part 8, 9 Spacer

Claims (5)

A ribbon microphone unit having a structure in which a ribbon diaphragm is arranged in the magnetic field of a pair of magnets that form a magnetic field,
A support made of a magnetic material,
A pair of first magnets attached to one side of the support, and a first ribbon diaphragm arranged in the magnetic field of the first magnets;
A pair of second magnets attached to the other surface side of the support, and a second ribbon diaphragm arranged in the magnetic field of the second magnets;
Comprising at least
Ribbon microphone unit and one end of the first ribbon diaphragm, and one end side of the second ribbon diaphragm, characterized in that it is electrically connected through the support. The ribbon microphone unit according to claim 1, wherein the support has a grounding terminal. The ribbon microphone unit according to claim 1, wherein the support is an annular frame. The first ribbon-type diaphragm and / or the second ribbon-type diaphragm are provided on one end side and the other end side thereof with a spacer thinner than the thickness of the first magnet and / or the second magnet. The ribbon microphone unit according to claim 1, wherein the ribbon microphone unit is attached to the support. A ribbon microphone comprising the ribbon microphone unit according to any one of claims 1 to 4.

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