JP2017123637A - Microphone - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize a single directivity type microphone having a ribbon type diaphragm.SOLUTION: A microphone includes a bidirectional ribbon type microphone unit (2) and an omnidirectional capacitor type microphone unit (3). The ribbon type microphone unit (2) includes a pair of ribbon type diaphragms (22b, 23b). The capacitor type microphone unit (3) is disposed between the pair of ribbon type diaphragms (22b, 23b).SELECTED DRAWING: Figure 4

Description

  The present invention relates to a microphone.

  A ribbon microphone, which is one type of microphone, includes a pair of magnets that form a magnetic field and a pair of ribbon diaphragms that vibrate upon receiving sound waves. The pair of ribbon diaphragms are disposed in the magnetic field. When receiving a sound wave, the pair of ribbon diaphragms vibrates in a magnetic field and generates an electric signal corresponding to the sound wave.

  The directivity of the ribbon microphone is generally bi-directional. On the other hand, it is desirable that the directivity of a microphone for the purpose of collecting musical sounds and for sound amplification is unidirectional.

  Unidirectionality of the ribbon microphone is realized by adding a bidirectional component and an omnidirectional component. Unidirectionality of the ribbon microphone is realized by using an acoustic tube built in the ribbon microphone. The ribbon diaphragm has a smaller mass and lower mechanical impedance than the diaphragms of other types of microphones (for example, dynamic microphones). In order to vibrate the ribbon diaphragm at a low frequency, the length of the acoustic tube becomes long. That is, a unidirectional ribbon microphone requires a long acoustic tube. Therefore, it is difficult to reduce the size of the unidirectional ribbon microphone.

  As a technique for miniaturizing a unidirectional ribbon microphone, a unidirectional ribbon microphone having a unidirectional transducer instead of an acoustic tube has been proposed (see, for example, Patent Document 1). .

JP2015-5861

  In the unidirectional ribbon microphone disclosed in Patent Document 1, a unidirectional transducer is attached in order to realize unidirectionality. Therefore, miniaturization of a microphone having a ribbon diaphragm is not sufficient.

  The present invention has been made to solve the above-described problems of the prior art, and aims to reduce the size of a unidirectional microphone including a ribbon diaphragm.

  The present invention is a microphone, comprising a bidirectional ribbon microphone unit and a non-directional condenser microphone unit, the ribbon microphone unit including a pair of ribbon diaphragms, The condenser microphone unit is arranged between a pair of ribbon diaphragms.

  According to the present invention, a unidirectional microphone including a ribbon diaphragm can be reduced in size.

It is a front view which shows embodiment of the microphone concerning this invention. FIG. 2 is a front sectional view of the microphone of FIG. 1. It is a front view of the microphone unit with which the microphone of FIG. 1 is provided. It is the sectional view on the AA line of the microphone unit of FIG. It is a front view of the magnetic circuit assembly with which the microphone unit of FIG. 3 is provided. FIG. 6 is a cross-sectional view of the magnetic circuit assembly of FIG. 5 taken along line XX. FIG. 4 is a cross-sectional view of the microphone unit of FIG. 3 taken along line BB.

● Microphone ●
Hereinafter, embodiments of a microphone according to the present invention will be described with reference to the drawings.

Microphone Configuration FIG. 1 is a front view showing an embodiment of a microphone according to the present invention.
FIG. 2 is a front sectional view of the microphone of FIG.
The microphone M picks up the sound wave from the sound source and outputs an electric signal corresponding to the sound wave. The microphone M includes a microphone case 1, a ribbon type microphone unit 2, and a condenser type microphone unit 3.

  In the following description, the front of the microphone M is the direction of the microphone M directed toward the sound source during sound collection (the direction on the front side in FIG. 1). The rear side of the microphone M is the opposite direction (the direction on the back side of the drawing in FIG. 1). Above the microphone M, a direction in which one end of the microphone M in the longitudinal direction of the microphone M (upward and downward direction in FIG. 1) (the upper end of the microphone M in FIG. 1) is directed (upward direction in FIG. 1). It is. The lower side of the microphone M is the direction opposite to the upper side of the microphone M (the lower direction in FIG. 1).

  The microphone case 1 houses a ribbon type microphone unit 2 and a condenser type microphone unit 3. The microphone case 1 is made of metal and has a bottomed cylindrical shape.

  The microphone case 1 includes two first window holes 11h, two second window holes (not shown), and a mesh 12. The first window hole 11h and the second window hole are rectangular. The first window holes 11h are arranged on the peripheral wall of the front surface (front surface) of the microphone case 1 along the longitudinal direction of the microphone case 1 (the vertical direction in the drawing of FIG. 1). The second window hole is arranged along the longitudinal direction of the microphone case 1 on the peripheral wall of the rear surface (back surface) of the microphone case 1. The second window hole is disposed to face the first window hole 11h. The first window hole 11h and the second window hole face the ribbon microphone unit 2 when the ribbon microphone unit 2 is housed in the microphone case 1. The first window hole 11 h and the second window hole are covered with the mesh 12 from the inside of the microphone case 1. The mesh 12 prevents foreign matter from entering the microphone case 1.

FIG. 3 is a front view of the ribbon microphone unit 2.
FIG. 4 is a cross-sectional view of the ribbon microphone unit 2 taken along the line AA.

  The ribbon microphone unit 2 collects sound waves from the sound source and outputs an electrical signal corresponding to the sound waves. The directivity of the ribbon microphone unit 2 is bi-directional. The ribbon microphone unit 2 includes a magnetic circuit assembly 21, a first diaphragm assembly 22, a second diaphragm assembly 23, a first protection plate 24, a second protection plate 25, and a mounting screw 26. .

FIG. 5 is a front view of the magnetic circuit assembly 21.
FIG. 6 is a sectional view of the magnetic circuit assembly 21 taken along the line XX.
5 and 6 also show the condenser microphone unit 3 in the magnetic circuit assembly 21. FIG.

  The magnetic circuit assembly 21 generates a magnetic flux in the magnetic circuit assembly 21 and fixes the condenser microphone unit 3. The magnetic circuit assembly 21 includes a yoke 21a, a first magnet 21b, and a second magnet 21c.

  The yoke 21a is made of a magnetic material such as iron. The yoke 21a has a substantially rectangular shape. The yoke 21a includes a substantially rectangular window hole 21ah1. The window hole 21ah1 is disposed at the center of the yoke 21a in the width direction (left and right direction in FIG. 5). The window hole 21ah1 penetrates the yoke 21a in the thickness direction of the yoke 21a (the frontward direction in the drawing of FIG. 5). The window hole 21ah1 forms a magnetic gap, which will be described later, and accommodates ribbon-type diaphragms 22b, 23b, which will be described later.

  The yoke 21a includes four screw holes 21ah2. The screw hole 21ah2 is a hole into which the attachment screw 26 is screwed (see FIG. 3). The two screw holes 21ah2 are arranged symmetrically with respect to the center line in the width direction of the yoke 21a (hereinafter referred to as “center line”) at the upper part of the yoke 21a. The remaining two screw holes 21ah2 are arranged symmetrically with respect to the center line at the lower part of the yoke 21a.

  The yoke 21a has an insertion hole 21ah3 penetrating in the vertical direction (the vertical direction in the drawing of FIG. 6) at the lower end thereof. The insertion hole 21ah3 will be described later.

  The first magnet 21b is, for example, a permanent magnet. The first magnet 21b has an elongated prismatic shape. The configuration of the second magnet 21c is the same as the configuration of the first magnet 21b. The first magnet 21b is fixed to the inner peripheral surface of the window hole 21ah1 along the longitudinal direction of the window hole 21ah1 (the vertical direction in FIG. 5). The second magnet 21c is fixed to the inner peripheral surface of the window hole 21ah1 so as to face the first magnet 21b along the longitudinal direction of the window hole 21ah1. A gap is provided between the first magnet 21b and the second magnet 21c.

  The magnetic pole of the surface facing the second magnet 21c of the first magnet 21b is different from the magnetic pole of the surface facing the first magnet 21b of the second magnet 21c. Therefore, the magnetic flux generated from the first magnet 21b and the second magnet 21c crosses the gap. That is, the magnetic circuit assembly 21 has a magnetic gap.

  As shown in FIGS. 3 and 4, the first diaphragm assembly 22 includes a substrate 22a, a ribbon-type diaphragm 22b, and a fixing portion 22c.

  The substrate 22a is made of a light metal such as aluminum. The substrate 22a has a rectangular shape. The board 22a includes a window hole 22ah1, four first screw insertion holes (not shown), and four second screw insertion holes 22ah2 (partially not shown). The window hole 22ah1 is disposed at the center of the substrate 22a. The window hole 22ah1 is a rectangle that is long in the longitudinal direction of the substrate 22a (the vertical direction in the drawing of FIG. 3). The first screw insertion holes are disposed at each of the four corners of the substrate 22a. The first screw insertion hole is a hole through which the attachment screw 26 is inserted.

  The two second screw insertion holes 22ah2 are arranged side by side between the two first screw insertion holes arranged side by side in the width direction of the substrate 22a (left and right direction in FIG. 3). That is, the board 22a is provided with two second screw insertion holes 22ah2 in the upper part thereof and two second screw insertion holes 22ah2 in the lower part thereof. The second screw insertion hole 22ah2 is a hole through which a mounting screw 22c3 described later is inserted.

  The ribbon diaphragm 22b vibrates according to the sound wave from the sound source and outputs an electrical signal corresponding to the vibration. The ribbon diaphragm 22b is made of metal such as aluminum foil. The ribbon diaphragm 22b has a bellows shape in which portions excluding both ends of the ribbon diaphragm 22b in the vertical direction (vertical direction in FIG. 3) are bent along the vertical direction. The length of the ribbon diaphragm 22b in the width direction (left and right direction in FIG. 3) is shorter than the length of the window hole 22ah1 in the width direction (left and right direction in FIG. 3).

  The fixing portion 22c fixes the ribbon diaphragm 22b to the substrate 22a. The fixing portion 22c includes a spacer 22c1, a metal fitting 22c2, and a mounting screw 22c3. The spacer 22c1 and the metal fitting 22c2 are attached to the upper portion of the substrate 22a and the lower portion of the substrate 22a, respectively, by the mounting screws 22c3 inserted through the second screw insertion holes 22ah2. The spacer 22c1 and the metal fitting 22c2 attached to the substrate 22a sandwich the upper end of the ribbon diaphragm 22b and the lower end of the ribbon diaphragm 22b. In other words, the ribbon diaphragm 22b is fixed to the substrate 22a by the fixing portion 22c.

  The second diaphragm assembly 23 includes a substrate 23a, a ribbon diaphragm 23b, and a fixing portion 23c. The configuration of the second diaphragm assembly 23 is the same as the configuration of the first diaphragm assembly 22. That is, the ribbon diaphragm 23b is fixed to the substrate 23a by the fixing portion 23c.

  The first diaphragm assembly 22 is attached to the front surface of the magnetic circuit assembly 21 (the surface on the right side in FIG. 4) with a mounting screw 26. The mounting screw 26 is inserted into the first screw insertion hole of the first diaphragm assembly 22 and screwed into the screw hole 21ah2 (see FIG. 5) of the magnetic circuit assembly 21. The first diaphragm assembly 22 covers the window hole 21ah1 of the magnetic circuit assembly 21 from the front of the magnetic circuit assembly 21. The ribbon diaphragm 22b is accommodated in the window hole 21ah1, as shown in FIG. As a result, the bellows-like portion of the ribbon diaphragm 22 b is disposed in the magnetic gap of the magnetic circuit assembly 21.

  The second diaphragm assembly 23 is attached to the rear surface of the magnetic circuit assembly 21 (the left side surface of FIG. 4) in the same manner as the first diaphragm assembly 22. The ribbon diaphragm 23b is accommodated in the window hole 21ah1 of the magnetic circuit assembly 21. As a result, the bellows-like portion of the ribbon diaphragm 23b accommodated in the window hole 21ah1 is disposed in the magnetic gap of the magnetic circuit assembly 21.

  The first diaphragm assembly 22 and the second diaphragm assembly 23 are attached to the magnetic circuit assembly 21. The first diaphragm assembly 22 and the second diaphragm assembly 23 sandwich the magnetic circuit assembly 21 from both the front surface and the rear surface of the magnetic circuit assembly 21.

  The first protection plate 24 protects the ribbon diaphragm 22b from magnetic powder and the like. The first protective plate 24 is made of metal. The first protective plate 24 includes a main body 24a and six leg portions 24b. The main body 24a has a rectangular plate shape when viewed from the front. The leg portions 24b are arranged at three locations on both side portions along the longitudinal direction (vertical direction) of the main body 24a. The leg 24b protrudes in a direction perpendicular to the main body 24a. The front end of the leg portion 24b bends at a right angle toward the outside of the leg portion 24b (the left-right direction in FIG. 3). The main body 24a includes a plurality of sound holes 24h. The sound hole 24h guides the sound wave from the sound source to the ribbon diaphragm 22b. The sound holes 24h are arranged substantially evenly in the main body 24a.

  The second protective plate 25 protects the ribbon diaphragm 23b from magnetic powder or the like. The second protective plate 25 includes a main body 25a and leg portions 25b. The main body 25a includes a sound hole 25h. The configuration of the second protection plate 25 is the same as the configuration of the first protection plate 24.

  The first protective plate 24 is attached to the front surface of the first diaphragm assembly 22. The leg portion 24 b of the first protective plate 24 is attached to the substrate 22 a of the first diaphragm assembly 22. The main body 24a of the first protective plate 24 is opposed to the ribbon diaphragm 22b and protects the ribbon diaphragm 22b.

  The second protective plate 25 is attached to the rear surface of the second diaphragm assembly 23. The leg portion 25 b of the second protective plate 25 is attached to the substrate 23 a of the second diaphragm assembly 23. The main body 25a of the second protection plate 25 is opposed to the ribbon diaphragm 23b and protects the ribbon diaphragm 23b.

  The condenser microphone unit 3 collects sound waves from the sound source. The directivity of the condenser microphone unit 3 is omnidirectional. The external shape of the condenser microphone unit 3 is cylindrical. The condenser microphone unit 3 includes a sound hole (not shown) on the upper end surface of the condenser microphone unit 3. The sound hole introduces sound waves from the sound source into the condenser microphone unit 3. The condenser microphone unit 3 is connected to a connector (not shown) via a cable C. The cable C is inserted into the insertion hole 21ah3 of the magnetic circuit assembly 21.

  7 is a cross-sectional view of the ribbon microphone unit 2 of FIG.

  The condenser microphone unit 3 is disposed inside the ribbon microphone unit 2, that is, between the pair of ribbon diaphragms 22b and the ribbon diaphragm 23b. The condenser microphone unit 3 is disposed between the pair of first magnets 21b and second magnets 21c. That is, the condenser microphone unit 3 is surrounded by the pair of ribbon diaphragms 22b and 23b and the pair of magnets 21b and 21c in the magnetic gap of the magnetic circuit assembly 21. In other words, the condenser microphone unit 3 is disposed inside the yoke 21a.

  The condenser microphone unit 3 is disposed at equal intervals from each of the pair of ribbon diaphragm 22b and ribbon diaphragm 23b. The upper end surface of the condenser microphone unit 3 is, as shown in FIG. 4, from the center in the longitudinal direction of the pair of ribbon diaphragms 22b and the ribbon diaphragm 23b (dashed line along the horizontal direction in FIG. 4). It is arranged below.

Acoustic Terminal The acoustic terminal of the ribbon microphone unit 2 and the acoustic terminal of the condenser microphone unit 3 will be described with reference to FIG.

  The acoustic terminal of the ribbon microphone unit 2 is a position of air that effectively applies sound pressure to the ribbon microphone unit 2. In other words, the acoustic terminal of the ribbon microphone unit 2 is the center position of air that moves simultaneously with the ribbon diaphragm 22b (ribbon diaphragm 23b) included in the ribbon microphone unit 2. That is, the acoustic terminal of the ribbon microphone unit 2 is an acoustic center with respect to the ribbon microphone unit 2.

  There are two acoustic terminals of the ribbon microphone unit 2 because the directivity of the ribbon microphone unit 2 is bi-directional. Of the two acoustic terminals of the ribbon microphone unit 2, one acoustic terminal is the center in the longitudinal direction of the ribbon diaphragm 22b, and the sound hole 24h of the first protection plate 24 in front of the first protection plate 24. It exists in the position close to. The other acoustic terminal is located at the center in the longitudinal direction of the ribbon diaphragm 23b and in the vicinity of the sound hole 25h of the second protective plate 25 behind the first protective plate 24.

  The acoustic terminal of the condenser microphone unit 3 is a position of air that effectively applies sound pressure to the condenser microphone unit 3. In other words, the acoustic terminal of the condenser microphone unit 3 is the center position of air that moves simultaneously with the diaphragm included in the condenser microphone unit 3. That is, the acoustic terminal of the condenser microphone unit 3 is an acoustic center with respect to the condenser microphone unit 3.

  There is one acoustic terminal of the condenser microphone unit 3 because the directivity of the condenser microphone unit 3 is omnidirectional. The acoustic terminal of the condenser microphone unit 3 is present at a position close to the sound hole of the condenser microphone unit 3 above the condenser microphone unit 3.

  The condenser microphone unit 3 is arranged inside the ribbon microphone unit 2 so that the acoustic terminals of the condenser microphone unit 3 are coaxial with the two acoustic terminals of the ribbon microphone unit 2. As a result, the acoustic terminals of the condenser microphone unit 3 are in the same plane in the vicinity of the two acoustic terminals of the ribbon microphone unit 2. In other words, the condenser microphone unit 3 is located inside the ribbon microphone unit 2 so as to be in the same plane and coaxial with the acoustic terminal of the capacitor microphone unit 3 and the acoustic terminal of the ribbon microphone unit 2. Placed in.

  The acoustic terminal of the condenser microphone unit 3 arranged inside the ribbon microphone unit 2 is coaxial with the acoustic terminal of the ribbon microphone unit 2 and close to the same plane. That is, the sound pressure of the sound wave received by the ribbon microphone unit 2 is the same as the sound pressure of the sound wave received by the condenser microphone unit 3. The condenser microphone unit 3 collects the same sound wave as that of the ribbon microphone unit 2. The electrical signal output from the condenser microphone unit 3 is added to the electrical signal output from the ribbon microphone unit 2. In other words, the omnidirectional component of the omnidirectional condenser microphone unit 3 is added to the bidirectional component of the bidirectional ribbon microphone unit 2. That is, the directivity of the microphone M is unidirectional.

  The condenser microphone unit 3 may be disposed inside the ribbon microphone unit 2 so as to receive the same sound pressure as the ribbon microphone unit 2 and collect the same sound wave. That is, for example, the upper end surface of the condenser microphone unit 3 is on the axis connecting the two acoustic terminals of the ribbon microphone unit 2, that is, the center in the longitudinal direction of the pair of ribbon diaphragm 22b and ribbon diaphragm 23b. May be arranged.

Summary According to the embodiment described above, the condenser microphone unit 3 is arranged inside the ribbon microphone unit 2. The acoustic terminal of the omnidirectional condenser microphone unit 3 is coaxial with the acoustic terminal of the bidirectional ribbon microphone unit 2 and close to the same plane. That is, the directivity of the microphone M is unidirectional by adding the bidirectional component of the ribbon microphone unit 2 and the omnidirectional component of the condenser microphone unit 3. As described above, the directivity of the microphone M is unidirectional with a simple structure in which the bidirectional microphone type microphone unit 2 and the non-directional condenser microphone unit 3 are combined. In the microphone M, a condenser microphone unit 3 is disposed inside the ribbon microphone unit 2. Therefore, miniaturization of the microphone M is realized.

M Microphone 1 Microphone case 11h Window hole 12 Mesh 2 Ribbon type microphone unit 21 Magnetic circuit assembly 21a York 21ah1 Window hole 21ah2 Screw hole 21ah3 Insertion hole 21b First magnet 21c Second magnet 22 First diaphragm assembly 22a Substrate 22ah1 Window Hole 22ah2 Second screw insertion hole 22b Ribbon type diaphragm 22c Fixing part 22c1 Spacer 22c2 Metal fitting 22c3 Mounting screw 23 Second diaphragm assembly 23a Substrate 23b Ribbon type diaphragm 23c Fixing part 24 First protection plate 24a Main body 24b Leg part 24h Sound hole 25 Second protective plate 25a Main body 25b Leg 25h Sound hole 26 Mounting screw 3 Condenser type microphone unit C Cable

Claims (5)

Bidirectional ribbon type microphone unit,
An omnidirectional condenser microphone unit,
Having
The ribbon microphone unit includes a pair of ribbon diaphragms,
The condenser microphone unit is disposed between the pair of ribbon diaphragms.
A microphone characterized by that. The acoustic terminal of the ribbon type microphone unit and the acoustic terminal of the condenser type microphone unit exist in the same plane.
The microphone according to claim 1. A magnetic circuit assembly having a magnetic gap;
Having
The magnetic circuit assembly includes:
A yoke with a window hole;
A magnet fixed to the window hole;
With
The pair of ribbon diaphragms are disposed in the magnetic gap,
The condenser microphone unit is disposed in the yoke.
The microphone according to claim 1. The condenser type microphone unit is disposed at a position equidistant from the pair of ribbon type diaphragms.
The microphone according to claim 3. Adding the electrical signal output from the ribbon microphone unit and the electrical signal output from the capacitor microphone unit;
The microphone according to claim 1.

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