JPH089493A - Speaker device - Google Patents

Abstract

(57) [Summary] [Structure] The inside of the hollow hole 15 of the pole piece 3 on the back side of the dust cap 7 is provided with the groove portion 12 provided in the pole piece 3.
Via the rear end side of the voice coil 5 to communicate with the void portion 14 between the pole piece 3 and the magnet 1, and the void portion 14 via the through hole 13 provided in the back plate 2. , And communicated with the outside. As a result, the air in the space 14 into which the voice coil 5 enters enters and leaves the outside by the movement of the dust cap 7 accompanying the vibration of the diaphragm 6.
Is cooled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speaker device for converting an electric signal into sound.

[0002]

2. Description of the Related Art Heretofore, there has been proposed a speaker device which has a magnetic circuit and which is supplied with an electric signal to generate vibration of a diaphragm to convert the electric signal into sound.

As shown in FIG. 18, such a speaker device has a magnetic circuit formed by arranging a pole piece 103 and a magnet 101 on the front side of a back plate 102. The back plate 102 is formed of a high magnetic permeability material such as iron into a substantially disc shape,
A through hole 113 is provided in the central portion. The magnet 1
01 is formed in a ring shape and is used for the back plate 10
It is fixed to the peripheral side portion of the front surface of No. 2. The pole piece 103 is made of a material similar to that of the back plate 102 and is formed into a substantially cylindrical shape having a hollow portion 115 in the central portion. The pole piece 103 is fixed to the central portion of the front surface of the back plate 102, and connects the hollow portion 115 and the through hole 113 of the back plate 102.

A ring-shaped top plate 104 made of a high magnetic permeability material is fixed to the front surface of the magnet 101. The inner peripheral portion of the top plate 104 and the outer peripheral portion of the front end side portion of the pole piece 103 form a magnetic gap portion 111.

On the front surface of the top plate 104,
The frame 110 is attached by screws 116. The frame 110 is formed to have a substantially hollow conical shape, a rear surface portion of a central portion thereof is fixed to the top plate 104, and a peripheral edge portion thereof extends toward the front side. The frame 110 has a through hole at the center.

An outer peripheral portion of a conical diaphragm 106 is joined to a peripheral portion of the frame 110 via an annular edge 108 made of a flexible material. A voice coil 105 is attached to the central portion of the diaphragm 106 toward the rear side. The voice coil 105 has a rear end portion at the magnetic gap portion 11
It has entered into 1. A front end side portion of the voice coil 105 near the joint to the diaphragm 106 is joined to a rear side portion of the frame 110 via an annular damper 109 made of a flexible material.

The front end of the voice coil 105 is closed by a dome-shaped center cap 107. The center cap 107 forms a part of the central portion of the diaphragm 106.

In such a speaker device, the electric signal is supplied to the voice coil 105, and the voice coil 105 generates a driving force in the front-back direction by the magnetic flux in the magnetic gap portion 111. This driving force vibrates the diaphragm 106 in the front-rear direction to generate sound.

[0009]

By the way, in the speaker device as described above, the Joule heat generated by the voice coil 105 being supplied with the electric signal causes the voice coil 105 and the voice coil 105 to have the Joule heat. There is a possibility that the surrounding members may be heated and the members may be melted or damaged due to carbonization.

The void 114 formed on the rear side of the magnetic gap portion 111 into which the voice coil 105 is inserted through the magnetic gap portion 111 is formed by the pole piece 103, the back plate 102 and the magnet 101. It is a closed space, and the heat generated by the voice coil 105 is easily stored.

Particularly, when a high output signal of about 400 W to 600 W is continuously input for a long time of, for example, 2 hours or more, as shown by A in FIG. The temperature of 105 reaches a high temperature of 240 ° C to 340 ° C.

In order to prevent such damage due to the heat generated by the voice coil 105, it is conceivable that each member constituting the speaker device is made of a material having a high heat resistant temperature limit.

However, while satisfying various characteristics,
Moreover, it is difficult to select a material having sufficient heat resistance, and it is expected that the output of the electric signal input to the speaker device will be further increased in the future. Has a limit.

By attaching a so-called heat sink member to the magnetic circuit or attaching an aluminum ring near the voice coil 105,
It is conceivable to release the heat generated by the voice coil 105 to the outside.

However, due to the heat sink and the aluminum ring, sufficient heat cannot be released and it is not possible to cope with the high output of the electric signal.

It is conceivable that the voice coil 105 is cooled by directly blowing the air on the outside to the voice coil 105.

However, blowing the outside air directly onto the voice coil 105 requires a device for feeding the outside air into the magnetic circuit, which not only complicates the device structure but also causes abnormal noise due to the inflow of air. There is a possibility that it will be generated, and it is not appropriate as the configuration of the speaker device.

A speaker device has been proposed in which the width of a part of the magnetic gap portion 111 is widened to form a ventilation portion, and outside air is passed through the ventilation portion to cool the voice coil 105.

However, if the width of the magnetic gap portion 111 is not constant over the entire circumference, the output is reduced due to the reduction of the total amount of magnetic flux in the magnetic gap portion 111, and the magnetic gap portion 111 has a smaller width. Distortion may occur due to the non-uniform magnetic flux density. Further, the cross-sectional area of the ventilation part needs to be set to a certain area or less in order for the magnetic gap part 111 to function as a magnetic gap, so that the voice coil 105 cannot be cooled sufficiently. In addition, there is a fear that the sound quality adjustment cannot be performed by the compliance adjustment of the diaphragm 106.

Therefore, the present invention is proposed in view of the above circumstances, and it is an object of the present invention to provide a speaker device capable of sufficiently suppressing the temperature rise of the voice coil without complicating the structure. To aim.

[0021]

In order to solve the above problems and achieve the above objects, a speaker device according to the present invention is provided with a back plate portion and a ring-shaped magnet disposed on the front side of the back plate portion. A magnetic circuit having a ring-shaped pole piece portion and a ring-shaped top plate portion and forming a magnetic gap portion between an outer peripheral portion of the pole piece portion and an inner peripheral portion of the top plate portion, A diaphragm having a voice coil disposed on the front side of the magnetic circuit and inserted into the magnetic gap portion is attached to the back surface, and a hollow portion in the center of the pole piece portion on the back surface of the diaphragm. A first airway communicating with a void formed continuously with the magnetic gap on the rear side of the magnetic gap, and a second airway communicating with the void on the rear side of the back plate. Airway It is one that is equipped with a.

Further, in the present invention, in the above speaker device, the first airway is constituted by a groove portion formed on the rear end side of the pole piece portion and a front surface portion of the back plate portion, and the second airway is provided. Is configured by a through hole formed in the back plate portion.

Further, in the present invention, in the above speaker device, the first airway has a groove portion formed from a recess formed in a central portion of the front surface of the back plate portion toward an outer peripheral side of the back plate portion. And a rear end portion of the pole piece portion, and the second airway is constituted by a through hole formed in the back plate portion.

Further, in the present invention, in the above speaker device, the first airway is constituted by a first through hole formed in a side wall portion of the pole piece portion, and the second airway is the pole. The pole piece is formed of a groove formed at the rear end of the piece and a second through hole formed in the central portion of the back plate. A partition wall portion that separates the hole from the groove portion is provided.

In the speaker device according to the invention, the magnet is attached to a central portion of the front surface of the back plate portion, the pole piece portion is attached to the front surface of the magnet, and the back plate portion is attached. Has a peripheral wall portion surrounding the periphery of the magnet at a peripheral edge portion, the top plate portion is attached to a front end portion of the peripheral wall portion of the back plate portion, and the first airway is a front surface of the back plate portion. And a rear end portion of the magnet, the groove portion being formed toward the outer peripheral side of the back plate portion from the concave portion formed in the center portion of the magnet,
The second airway is constituted by a through hole formed in the back plate portion.

[0026]

In the speaker device according to the present invention, the diaphragm vibrates so that the air pressure in the void portion formed continuously with the magnetic gap portion on the rear side of the magnetic gap portion causes the back surface of the diaphragm. The central hollow portion of the pole piece portion on the side is changed via a first airway communicating with the void portion, and the air in the void portion is moved outward from the void portion toward the rear side of the back plate portion. In and out via a second airway communicating with the.

Further, in the above speaker device, the first airway is constituted by a groove portion formed on the rear end side of the pole piece portion and the front surface portion of the back plate portion, and the second airway is the back portion. When the pole piece and the back plate are formed by the through holes formed in the plate portion, the pole piece and the back plate can be additionally processed.

In the above speaker device, the first airway has a groove portion and a pole piece portion which are formed from the recess formed in the central portion of the front surface of the back plate portion toward the outer peripheral side of the back plate portion. And a rear end portion, and the second airway is constituted by a through hole formed in the back plate portion,
It can be constructed by additionally processing only the back plate portion.

Further, in the above speaker device, the first airway is constituted by a first through hole formed in a side wall portion of the pole piece portion, and the second airway is provided behind the pole piece portion. The first through hole and the groove portion are formed in the hollow portion of the central portion of the pole piece portion, the groove portion being formed in the end portion and the second through hole formed in the central portion of the back plate portion. In the case where a partition wall portion that separates the pole piece and the back plate is provided, the pole piece and the back plate can be additionally processed.

In the speaker device, the magnet is attached to a central portion of the front surface of the back plate portion, the pole piece portion is attached to the front surface of the magnet, and the back plate portion is a peripheral portion. A peripheral wall portion surrounding the magnet, the top plate portion is attached to a front end portion of the peripheral wall portion of the back plate portion, and the first airway is a central portion of a front surface portion of the back plate portion. And a rear end portion of the magnet, the second airway being formed by a through hole formed in the back plate portion. In the case of being configured, a so-called inner magnet type magnetic circuit is configured, and only the back plate portion is additionally processed. It can be configured Te.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below with reference to the drawings. The speaker device according to the present invention is a device which has a magnetic circuit and which is supplied with an electric signal to generate vibration of the diaphragm to convert the electric signal into sound.

As shown in FIGS. 1 to 12, the magnetic circuit includes a back plate 2 serving as a back plate portion, a ring-shaped magnet 1 arranged on the front side of the back plate 2, and a pole piece portion. Has a ring-shaped pole piece 3 and a ring-shaped top plate 4 that serves as a top plate portion, and forms a magnetic gap portion 11 between the outer peripheral portion of the pole piece 3 and the inner peripheral portion of the top plate 4. Is what you are doing.

The back plate 2 is made of a highly magnetically permeable material such as iron and is formed into a substantially disc shape. The magnet 1 is a so-called ferrite magnet or neodymium magnet, is formed in a ring shape, and is fixed to the peripheral side portion of the front surface portion of the back plate 2. The pole piece 3 is made of a material similar to that of the back plate 2 and is formed into a substantially cylindrical shape having a hollow portion 15 in the central portion. This pole piece 103
Is the central portion of the front surface of the back plate 102,
That is, the magnet 1 is located inside and fixed to the magnet 1. This magnetic circuit is a so-called external magnet type magnetic circuit.

A ring-shaped top plate 4 made of a high magnetic permeability material is fixed to the front surface of the magnet 1. The inner peripheral portion 18 of the top plate 4 and the outer peripheral portion 19 of the front end portion of the pole piece 3 face each other to form the magnetic gap portion 11.

A frame 10 is attached to the front surface of the top plate 4 with screws 16. The frame 10 is formed to have a substantially hollow conical shape, a rear surface portion of a central portion thereof is fixed to the top plate 4, and a peripheral edge portion thereof extends toward the front side. The frame 10 has a through hole at the center.

The outer peripheral portion of the conical diaphragm 6 is joined to the peripheral portion of the frame 10 through an annular edge 8 made of a flexible material. This diaphragm 6
Are arranged in front of the magnetic circuit so as to be covered by the frame 10.

On the back surface of the central portion of the diaphragm 6,
The voice coil 5 is attached to the rear side. The voice coil 5 has its rear end side portion inserted into the magnetic gap portion 11. This voice coil 5
The front end side portion in the vicinity of the joint to the diaphragm 6 of
It is joined to the rear side portion of the frame 10 via an annular damper 9 made of a flexible material.

The front end of the voice coil 5 is closed by a dome-shaped center cap 7.
The center cap 7 forms a part of the central portion of the diaphragm 6.

In the above magnetic circuit, the electric signal is supplied to the voice coil 5, and the voice coil 5 is supplied with the electric signal.
Generate a driving force in the front-back direction by the magnetic flux in the magnetic gap portion 11. This driving force vibrates the diaphragm 6 in the front-rear direction to generate sound.

The speaker device has first and second airways in the magnetic circuit section.

The first airway has a hollow portion 15 at the center of the pole piece 3 which is the back side of the diaphragm 6.
The magnetic gap portion 11 is communicated with a void portion 14 formed continuously with the magnetic gap portion 11 on the rear side thereof. Since the front side of the void portion 14 is continuous with the magnetic gap portion 11, the voice coil 5 is inserted from the front side. The void portion 14 is a space formed by being surrounded by the outer peripheral surface portion of the pole piece 3, the inner peripheral surface portion of the magnet 1, and the front surface portion of the back plate 2.

The second airway communicates the void portion 14 with the rear side of the back plate 2.

As shown in FIGS. 1 to 12, the first airway is composed of a groove portion 12 formed on the rear end side of the pole piece 3 and a front surface portion of the back plate 2. Further, the second airway is composed of a plurality of through holes 13 formed in the back plate 2. These through holes 13 are arranged and formed on the circumference surrounding the central portion of the back plate 2, and the gap portion 1 is formed.
It is located on the rear side of No. 4.

In this speaker device, the diaphragm 6 is used.
Is vibrated by the input of the electric signal, the atmospheric pressure in the hollow portion 15 of the pole piece 3 periodically fluctuates, and the fluctuation of the atmospheric pressure passes through the groove portion 12 which is the first airway and the void portion 14 Is transmitted within. Then, the void 14
The air pressure in the inside fluctuates, and the air in the void portion 14 moves in and out of the back side of the back plate 2 through the through holes 13 which are the second airways. Therefore, in this speaker device, the voice coil 5 is cooled by the air flowing in and out of the void portion 14 to the outside.

The temperature rise of the voice coil 5 in this speaker device was measured by continuously supplying a constant output pink noise to the voice coil 5, as shown in FIG. The pink noise is white noise that increases by 6 dB per octave as the frequency increases, and is generated by the pink noise generator 26. This pink noise is supplied to the voice coil 5 of the magnetic circuit through a bandpass filter (bandpass filter) 27 having a passband of 50 Hz to 500 Hz. On the other hand, a detecting device 28 for detecting the temperature of the voice coil 5 from the value of the direct current resistance of the voice coil 5 is connected to the voice coil 5.

The above-described measuring method is performed by the American Acoustic Engineering Association (AUDIO ENGINEERING S
OCIETY, INC. ) Recommended standards (AES Rec
It is in accordance with the Common Practice.

With such a measuring method, as shown by B in FIG. 14, the state of the temperature rise of the voice coil 5 was measured. That is, when the input of 400 W is continued for 2 hours or more, the temperature of the voice coil 5 is about 170 ° C., and the input of 600 W is 24
The temperature is about 0 ° C to 270 ° C, which is about 30% lower than that of the voice coil of the conventional speaker device shown by A in FIG.

Since an adhesive having a heat resistance limit of about 220 ° C. is often used for adhering the voice coil 5, the present invention can realize high input resistance of the speaker device.

In the speaker device according to the present invention, the first airway has an outer peripheral side of the back plate 2 with respect to a recess formed in the central portion of the front surface of the back plate 2, as shown in FIG. Groove portion 20 formed toward
And the rear end of the pole piece 3 may be used. In this example, the second airway is constituted by the plurality of through holes 13 formed in the back plate 2.

Also in the speaker device having the magnetic circuit having such a configuration, the air in the void portion 14 enters and leaves the outside through the through holes 13 to cool the voice coil 5. Planned.

Further, in the speaker device according to the present invention, the first airway is constituted by the first through hole 22 formed in the side wall portion of the pole piece 3, as shown in FIG. Good. Further, in this example, the second airway is constituted by the groove portion 23 formed in the rear end portion of the pole piece 3 and the second through hole 21 formed in the central portion of the back plate 2. There is. Further, in the hollow portion 15 in the central portion of the pole piece 3, a partition wall portion 24 that separates the first through hole 22 and the groove portion 23 is arranged.

Also in the speaker device having the magnetic circuit having such a configuration, the air in the void portion 14 enters and leaves the outside through the groove portion 23 and the through hole 21, and the voice coil 5 Is cooled.

As shown in FIG. 17, the speaker device according to the present invention may have a so-called inner magnet type magnetic circuit.

In this magnetic circuit, the magnet 1 is attached to the central portion of the front surface of the back plate 2. The magnet 1 is a so-called ferrite magnet or neodymium magnet, and is formed in a cylindrical shape having a hollow portion 14. The pole piece 3 is formed in a thin ring shape, and the magnet 1
It is attached to the front part of the.

The back plate 2 has a yoke portion, which is a peripheral wall portion surrounding the periphery of the magnet 1, in the peripheral portion. The top plate 4 is attached to the front end portion of the yoke portion of the back plate 2.

In this magnetic circuit, the magnetic gap portion 11 is formed by the outer peripheral surface portion of the pole piece 3 and the inner peripheral surface portion of the top plate 4. The gap formed continuously with the magnetic gap portion 11 on the rear side of the magnetic gap portion 11 includes a rear portion of the top plate 4, an outer peripheral surface portion of the magnet 1, and a yoke portion of the back plate 2. It is formed as a space surrounded by the inner peripheral surface portion 25 and the front surface portion of the back plate 2.

The frame 10 supporting the vibrating plate 6 is attached to the front surface of the top plate 4.

The first airway has a groove 20 formed toward the outer peripheral side of the back plate 2 from a recess formed in the center of the front surface of the back plate 2.
It is composed of the rear end of the magnet 1. Further, the second airway is composed of a plurality of through holes 13 formed in the back plate 2. These through holes 13 are arranged and formed on the circumference surrounding the central portion of the back plate 2, and are located on the rear side of the void portion.

Also in the speaker device having the magnetic circuit having such a structure, the air in the void portion goes in and out of the outside through the through holes 13 to cool the voice coil 5. .

[0060]

As described above, in the speaker device according to the present invention, the vibrating plate vibrates to cause the air pressure in the void portion formed continuously with the magnetic gap portion on the rear side of the magnetic gap portion. Through the first airway that communicates the hollow portion of the central portion of the pole piece portion that is the back side of the diaphragm with the void portion, and the air in the void portion moves the void portion into the back plate. In and out via a second airway that communicates to the outside on the rear side of the section.

Therefore, in this speaker device, the air in the void contacting the voice coil that has entered the magnetic gap is released to the outside through the second airway, and the outside air is released from the void. The voice coil is cooled because it flows into the interior and contacts the voice coil. Particularly when the speaker device for a low band of about 50 Hz to 500 Hz is configured, the vibration effect is large because the amplitude of the diaphragm is large.

By cooling the voice coil, a high input resistance can be realized, and a change in direct current resistance of the voice coil can be suppressed, so that a reduction in conversion efficiency can be suppressed.

In this speaker device, the first airway is composed of a groove formed on the rear end side of the pole piece portion and the front surface of the back plate portion, and the second airway is the back plate portion. When it is configured by the through hole formed in the above, the pole piece and the back plate can be additionally processed.

Further, in the above speaker device, the first airway has a groove portion and a pole piece portion which are formed from the concave portion formed in the central portion of the front surface of the back plate portion toward the outer peripheral side of the back plate portion. When the second airway is constituted by a rear end portion and the second airway is constituted by a through hole formed in the back plate portion, it is constituted by additionally machining only the back plate portion. You can

Further, in the speaker device, the first airway is constituted by a first through hole formed in the side wall of the pole piece portion, and the second airway is the rear end portion of the pole piece portion. And a second through hole formed in the central portion of the back plate portion. The first through hole and the groove portion are separated from each other in the hollow portion of the central portion of the pole piece portion. When the partition is provided, it can be constructed by additionally machining the pole piece and the back plate.

In the above speaker device, the magnet is attached to the central portion of the front surface of the back plate portion, the pole piece portion is attached to the front surface portion of the magnet, and the back plate portion is attached to the peripheral portion of the magnet. A recessed portion having a peripheral wall portion surrounding the periphery of the back plate portion, the top plate portion being attached to the front end portion of the peripheral wall portion of the back plate portion, and the first airway being formed in the central portion of the front surface portion of the back plate portion. And a rear end portion of the magnet, and a second airway is formed of a through hole formed in the back plate portion. In that case, a so-called inner magnet type magnetic circuit is configured,
Further, it can be constructed by additionally machining only the back plate portion.

That is, the present invention can provide a speaker device capable of sufficiently suppressing the temperature rise of the voice coil without complicating the structure.

In the speaker device according to the present invention, the width of the magnetic gap is constant over the entire circumference,
Since the magnetic flux in the magnetic gap portion has a constant magnetic flux density over the entire circumference of the magnetic gap portion, there is no fear that the output will be reduced due to the decrease in the total amount of magnetic flux or the distortion due to the non-uniformity of the magnetic flux density. .

Furthermore, in this speaker device, the sound quality can be easily adjusted by adjusting the compliance of the diaphragm by appropriately setting the cross-sectional area of each airway.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a configuration of a speaker device according to the present invention.

FIG. 2 is an exploded perspective view showing a configuration of a magnetic circuit of the speaker device.

FIG. 3 is a front view showing the shape of a pole piece forming the magnetic circuit of the speaker device.

FIG. 4 is a vertical cross-sectional view showing the shape of the pole piece.

FIG. 5 is a rear view showing the shape of the pole piece.

FIG. 6 is a front view showing a shape of a top plate that constitutes a magnetic circuit of the speaker device.

FIG. 7 is a vertical cross-sectional view showing the shape of the top plate.

FIG. 8 is a front view showing the shape of a magnet forming a magnetic circuit of the speaker device.

FIG. 9 is a vertical cross-sectional view showing the shape of the magnet.

FIG. 10 is a front view showing a shape of a back plate which constitutes a magnetic circuit of the speaker device.

FIG. 11 is a vertical cross-sectional view showing the shape of the back plate.

FIG. 12 is a rear view showing the shape of the back plate.

FIG. 13 is a block diagram showing a configuration of an apparatus for measuring a temperature of a voice coil of a speaker device.

FIG. 14 is a graph showing a temperature rise of a voice coil in a speaker device according to the present invention and a conventional speaker device.

FIG. 15 is a vertical cross-sectional view showing another example of the configuration of the speaker device according to the present invention, in which the airway is formed on the back plate.

FIG. 16 is a vertical cross-sectional view showing another example of the configuration of the speaker device according to the present invention, in which the airway is formed on the side surface portion of the pole piece.

FIG. 17 is a vertical cross-sectional view showing another example of the configuration of the speaker device according to the present invention, in which the magnetic circuit is a so-called inner magnet type.

FIG. 18 is a vertical cross-sectional view showing the configuration of a conventional speaker device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 magnet 2 back plate 3 pole piece 4 top plate 5 voice coil 6 diaphragm 7 center cap 11 magnetic gap 12 groove part 13 through hole 14 void part 20 groove part 21 second through hole 22 first through hole 23 groove part

Claims (5)

[Claims] 1. A back plate portion, and a ring-shaped magnet, a ring-shaped pole piece portion, and a ring-shaped top plate portion arranged on the front side of the back plate portion. A magnetic circuit forming a magnetic gap portion between an outer peripheral portion and an inner peripheral portion of the top plate portion, and a voice coil which is disposed on the front side of the magnetic circuit and has entered the magnetic gap portion on the back surface. The diaphragm attached to the portion, and the hollow portion of the central portion of the pole piece portion, which is the back side of the diaphragm, on the rear side of the magnetic gap portion to the void portion formed continuously with the magnetic gap portion. First to communicate
And a second airway communicating the air gap with the outside of the back plate at the rear side. 2. The first airway is constituted by a groove portion formed on the rear end side of the pole piece portion and a front surface portion of the back plate portion, and the second air passage is formed by the transparent portion formed on the back plate portion. The speaker device according to claim 1, wherein the speaker device is formed of a hole. 3. The first airway is formed by a groove portion formed toward the outer peripheral side of the back plate portion from a recess portion formed in the central portion of the front surface portion of the back plate portion and a rear end portion of the pole piece portion. The speaker device according to claim 1, wherein the second airway is constituted by a through hole formed in the back plate portion. 4. The first airway is constituted by a first through hole formed in a side wall portion of the pole piece portion, and the second airway is formed with a groove portion formed in a rear end portion of the pole piece portion. The second formed on the central portion of the back plate portion
2. The speaker device according to claim 1, wherein a partition wall portion that separates the first through hole and the groove portion is provided in a hollow portion in a central portion of the pole piece portion. 5. The magnet is attached to the central portion of the front surface of the back plate portion, the pole piece portion is attached to the front surface portion of the magnet, and the back plate portion surrounds the periphery of the magnet at a peripheral edge portion. A top plate part is attached to a front end part of the peripheral wall part of the back plate part, and a first airway has a recess formed in a central part of the front part of the back plate part. The speaker according to claim 1, wherein the speaker is configured by a groove portion formed toward the outer peripheral side of the portion and a rear end portion of the magnet, and the second airway is configured by a through hole formed in the back plate portion. apparatus.