JP2021118526A - Speaker system - Google Patents

Abstract

To provide a speaker system that makes two voice coils bear a desired frequency band and makes the sound pressure uniform.SOLUTION: A speaker system 100 includes an annular vibrating body 101, a first bobbin 102 having a tubular shape and physically connected to the vibrating body 101, a first voice coil 103 wound around the first bobbin 102, a second bobbin 104 having a tubular shape with a larger opening than the first bobbin 102 and physically connected to the vibrating body 101, a second voice coil 105 wound around the second bobbin 104, and an output unit that is electrically connected to the first voice coil 103 and the second voice coil 105 and outputs electric signals having different frequency characteristics to the first voice coil 103 and the second voice coil 105.SELECTED DRAWING: Figure 1

Description

The present invention relates to a speaker system, for example, a speaker system used for a tweeter.

As a speaker capable of producing sound in a wide frequency band, there is a double voice coil speaker equipped with two voice coils. In a double voice coil speaker, a small-diameter voice coil produces sound in a relatively high frequency band, and a large-diameter voice coil produces sound in a relatively low frequency band, thereby producing sound in a wide frequency band.

Patent Document 1 describes a speaker including a large-diameter voice coil unit mounted on the outer edge of the main vibrating portion and a small-diameter voice coil unit mounted on the inner edge of the main vibrating portion.

Japanese Unexamined Patent Publication No. 2006-101202

However, in the conventional double voice coil speaker, there is a problem that it is not possible to make the two voice coils bear a desired frequency band and to make the sound pressure uniform. Further, in the conventional double voice coil speaker, when piston motion is desired, there is a problem that it is not possible to make the frequency bands of the two voice coils uniform and the amplitude amount to be the same.

The speaker system of one embodiment includes an annular vibrating body, a first bobbin having a tubular shape and physically connected to the vibrating body, a first voice coil wound around the first bobbin, and the above-mentioned. A second bobbin having a tubular shape with an opening portion larger than that of the first bobbin and physically connected to the vibrating body, a second voice coil wound around the second bobbin, the first voice coil, and the above. It is electrically connected to the second voice coil, and the first voice coil and the second voice coil are provided with an output unit that outputs electric signals having different frequency characteristics.

According to the present invention, it is possible to provide a speaker system in which two voice coils are provided with a desired frequency band and the sound pressures are made uniform. Further, according to the present invention, it is possible to provide a speaker system in which the frequency bands of the two voice coils are aligned and the amplitude amounts are aligned at the same time.

It is sectional drawing of the speaker which concerns on Embodiment 1. FIG. It is a top view of the speaker which concerns on Embodiment 1. FIG. It is a circuit diagram which shows an example of the electric circuit of the speaker system which concerns on Embodiment 1. FIG. It is a graph which shows an example of the frequency band of a speaker system. It is a graph which shows an example of a sound pressure and a frequency characteristic in a conventional double voice coil speaker. It is a graph which shows an example of a sound pressure and a frequency characteristic in the speaker system of Embodiment 1. FIG. It is sectional drawing of the modification of the speaker which concerns on Embodiment 1. FIG. It is sectional drawing of the modification of the speaker which concerns on Embodiment 1. FIG. It is a circuit diagram which shows the modification of the electric circuit of the speaker system which concerns on Embodiment 1. FIG. It is a graph which shows an example of a sound pressure and a frequency characteristic in the modification of the speaker system of Embodiment 1. It is sectional drawing which shows an example of the speaker which concerns on Embodiment 2. FIG. It is sectional drawing which shows an example of the vibration transmission of a double voice coil speaker. FIG. 5 is a cross-sectional view showing an example of a speaker in which a cap 108 is physically connected to a main diaphragm 121. It is sectional drawing which shows an example of the vibration transmission of the speaker of Embodiment 2. It is a schematic diagram for demonstrating the pressure fluctuation in the speaker which does not have a partition body. It is a schematic diagram for demonstrating the pressure fluctuation in the speaker system of Embodiment 2.

In order to clarify the explanation, the following descriptions and drawings have been omitted or simplified as appropriate. Further, in each drawing, the same elements are given the same reference numerals, and duplicate explanations are omitted as necessary.

Embodiment 1
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of the speaker according to the first embodiment. In FIG. 1, the speaker 100 includes a vibrating body 101, a first bobbin 102, a first voice coil 103, a second bobbin 104, a second voice coil 105, a magnet 106, a plate 107, and a cap 108. A yoke 109, a frame 110, and a partition 111 are provided. Further, FIG. 2 is a top view of the speaker according to the first embodiment.

The vibrating body 101 includes a main diaphragm 121 and an outer support portion 122. The vibrating body 101 has an annular shape. The vibrating body 101 may have an arbitrary cross-sectional shape, but may have a curved shape protruding toward the front side of the speaker as shown in FIG. Further, the vibrating body 101 is preferably formed of synthetic resin, paper, cloth or the like.

The first bobbin 102 has a tubular shape. The first bobbin 102 is physically connected to the vibrating body 101.

The first voice coil 103 is a coil that is wound around the first bobbin 102 and vibrates the first bobbin 102.

The second bobbin 104 has a tubular shape and has a larger opening than the first bobbin 102. For example, when the first bobbin 102 and the second bobbin 104 are cylindrical, the second bobbin 104 has a larger diameter than the first bobbin 102. The second bobbin 104 is connected to the vibrating body 101.

The second voice coil 105 is a coil that is wound around the second bobbin 104 and vibrates the second bobbin 104.

The vibrating body 101 vibrates due to the vibration of the first voice coil 103 and the second voice coil 105. Then, the vibration of the vibrating body 101 can vibrate the air and emit sound waves.

The second voice coil 105 is located outside the first voice coil 103. The size of the second voice coil 105 is larger than that of the first voice coil 103. Here, the size means any of the inner diameter, the outer diameter, the length in the circumferential direction, the area seen from the upper surface, and the volume.

Further, the second voice coil 105 and the first voice coil 103 may be any material as long as they can form an electromagnet. Therefore, the second voice coil 105 and the first voice coil 103 include one or more turns of the conductor.

The position where the second bobbin 104 is physically connected to the main diaphragm 121 is outside the position where the first bobbin 102 is physically connected to the main diaphragm 121. For example, the second bobbin 104 is physically connected to the outer edge of the main diaphragm 121, and the first bobbin 102 is physically connected to the inner edge of the main diaphragm 121. Here, the outer edge of the main diaphragm 121 is a boundary portion between the main diaphragm 121 and the outer support portion 122. The inner edge of the main diaphragm 121 is the open end of the vibrating body 101.

The magnet 106 is, for example, a permanent magnet.

The plate 107 is an annular flat plate connected to the magnet 106. For example, the plate 107 is made of a ferromagnetic material.

The cap 108 is physically connected to the first bobbin 102 and covers the top of the first bobbin 102. In the example of FIG. 1, the height of the top of the cap 108 (in the Z-axis direction) is lower than the height of the top of the main diaphragm 121 of the vibrating body 101.

The magnetic circuit constitutes a first magnetic gap on the inner circumference and a second magnetic gap on the outer circumference, and the first voice coil 103 is in the first gap and the second voice coil 105 is in the second gap. Arranged to receive magnetic flux.

The yoke 109 is connected to the magnet 106 and forms a magnetic circuit together with the magnet 106 and the plate 107. The magnetic circuit supplies magnetic energy to the two magnetic gaps in which the second voice coil 105 and the first voice coil 103 are arranged. For example, the yoke 109 is made of a ferromagnetic material.

The frame 110 is a member that fits with the outer circumference of the yoke 109 on the side surface and fixes the outer support portion 122 of the vibrating body 101 on the upper surface.

The partition body 111 is a structure that partitions the space formed by the second bobbin 104, the first bobbin 102, the main diaphragm 121, and the yoke 109 and the space formed by the first bobbin 102, the cap 108, and the yoke 109. be. The partition body 111 is a structure that is connected to the first bobbin 102 and the yoke 109 and has flexibility that can be deformed in response to the vibration of the first bobbin 102. For example, the partition 111 is an adhesive.

Next, the electric circuit part will be described. FIG. 3 is a circuit diagram showing an example of an electric circuit of the speaker system according to the first embodiment. In FIG. 3, the speaker system 300 includes a speaker 100 and an output unit 301.

The output unit 301 includes a capacitor C 302, a capacitor C 303, an input terminal 311 and an input terminal 312, an output terminal 321 and an output terminal 322, an output terminal 331, and an output terminal 332. The output unit 301 may be configured to include a filter F302 and a filter F303 (not shown) instead of the capacitor C302 and the capacitor C303. Further, the output unit 301 may be separate from the speaker 100.

The input terminal 311 and the input terminal 312 are terminals for inputting an electric signal. For example, the input terminal 311 and the input terminal 312 are connected to the output terminal of the audio device.

The output terminal 321 and the output terminal 322 are terminals connected to the second voice coil 105. Further, the output terminal 331 and the output terminal 332 are terminals connected to the first voice coil 103. Therefore, the output unit 301 is connected to the speaker 100 by four signal lines.

One end of the capacitor C302 is connected to the input terminal 311 and the other end is connected to the output terminal 321. Further, one end of the capacitor C303 is connected to the input terminal 311 and the other end is connected to the output terminal 331.
The input terminal 312 is connected to the output terminal 322 and the output terminal 332.

With the above configuration, the electric signal input to the output unit 301 has a frequency characteristic determined by the capacitance of the capacitor C302 and the DC resistance value of the second voice coil 105, or a cutoff frequency corresponding to the frequency characteristic of the filter F302. After being attenuated, it is output to the second voice coil 105. Then, the electric signal input to the output unit 301 is attenuated by a frequency characteristic determined by the capacitance of the capacitor C303 and the DC resistance value of the first voice coil 103, or a cutoff frequency corresponding to the characteristic of the filter F302. After that, it is output to the first voice coil 103. The output unit 301 may output the voltage of the electric signal output to the second voice coil 105 and the voltage output to the first voice coil 103 as different voltages by the filter F302 and the filter F303, and may output the cutoff frequency and the voltage. The output voltages may both have different frequency characteristics and output voltages.

The second voice coil 105, the first voice coil 103, and the woofer (not shown) share different frequency bands from each other.

FIG. 4 is a graph showing an example of the frequency band of the speaker system. In FIG. 4, the horizontal axis represents the frequency. The vertical axis indicates the sound pressure level (SPL).

In FIG. 4, the frequency characteristic 401 indicates the frequency band of the woofer. Further, the frequency characteristic 402 indicates the frequency band of the outer second voice coil. The frequency characteristic 403 indicates the frequency band of the inner first voice coil.

As shown in FIG. 4, the first voice coil 103 and the second voice coil 105 share different frequency bands from each other. In the speaker system of the first embodiment, the output unit 301 outputs electric signals having different frequency characteristics to the first voice coil 103 and the second voice coil 105.

Specifically, since the capacitance of the capacitor C302 and the capacitance of the capacitor C303 are independent of each other and can be different, the electricity output from the output unit 301 to the first voice coil 103 and the second voice coil 105. The signals have different frequency characteristics.

For example, the capacity of the capacitor C302 is larger than the capacity of the capacitor C303. Further, the DC resistance of the second voice coil 105 and the DC resistance of the first voice coil 103 are generally substantially the same. Therefore, the cutoff frequency of the filter composed of the capacitor C 302 and the second voice coil 105 is lower than the cutoff frequency of the filter composed of the capacitor C 303 and the first voice coil 103. That is, an electric signal attenuated at a lower cutoff frequency is input to the second voice coil 105 arranged on the outer side. An electric signal attenuated at a higher cutoff frequency is input to the first voice coil 103 arranged further inside.

As described above, the effect of outputting electric signals having different frequency characteristics to the inner first voice coil 103 and the outer second voice coil 105 will be described in comparison with the conventional double voice coil speaker.

FIG. 5 is a graph showing an example of sound pressure and frequency characteristics in a conventional double voice coil speaker. In FIG. 5, the horizontal axis represents the frequency. The vertical axis indicates the sound pressure level.
The frequency characteristic 501 of FIG. 5 shows the outer peripheral characteristic (frequency characteristic of sound pressure generated by the second voice coil 105) when an electric signal is input without passing through the filter F 303. The frequency characteristic 502 shows an inner peripheral characteristic (frequency characteristic of sound pressure generated by the first voice coil 103) when an electric signal is input without passing through the filter F302. The frequency characteristic 511 indicates the outer peripheral characteristic when an electric signal that has passed through the filter F303 is input. The frequency characteristic 512 indicates an inner peripheral characteristic when an electric signal that has passed through the filter F302 is input.

FIG. 6 is a graph showing an example of sound pressure and frequency characteristics in the speaker system of the first embodiment. In FIG. 6, the horizontal axis represents the frequency. The vertical axis indicates the sound pressure level.

The frequency characteristic 601 of FIG. 6 shows the frequency characteristic of the sound pressure generated by the outer voice coil when the electric signal is input without passing through the filter F303. The frequency characteristic 602 shows the frequency characteristic of the sound pressure generated by the inner voice coil when the electric signal is input without passing through the filter F302. The frequency characteristic 611 shows the frequency characteristic of the sound pressure generated by the outer voice coil when the electric signal passing through the filter F303 is input. The frequency characteristic 612 indicates the frequency characteristic of the sound pressure generated by the inner voice coil when the electric signal passing through the filter F302 is input.

Comparing FIGS. 5 and 6, in the conventional double voice coil speaker, the frequency characteristic 512 of the sound pressure generated by the inner voice coil is the frequency characteristic 511 of the sound pressure generated by the outer voice coil. Although the sound pressure is higher, in the first embodiment, the frequency characteristic 612 of the sound pressure generated by the inner voice coil and the frequency characteristic 611 of the sound pressure generated by the outer voice coil are used. ， The frequency characteristic that there is no step in the sound pressure is formed.

Specifically, the conventional double voice coil speaker has a circuit configuration that outputs a common electric signal to the outer voice coil and the inner voice coil. In other words, the first voice coil 103 and the second voice coil 105 were both connected to the common capacitor C302. Therefore, in order to vibrate the outer voice coil at a lower frequency than the inner voice coil, it was necessary to make the DC resistance of the outer voice coil larger than the DC resistance of the inner voice coil. However, if the DC resistance of the outer voice coil is made larger than the DC resistance of the inner voice coil, the efficiency of acoustic conversion is inversely proportional to the DC resistance of the voice coil when the magnetic energy supplied to each voice coil is the same. , A driving force smaller than that of the inner bobbin is applied to the outer bobbin. Since the outer voice coil has a larger effective mass than the inner voice coil, the outer sound pressure is small and the inner sound pressure is large.

If the DC resistance of the outer voice coil is made smaller than the DC resistance of the inner voice coil in the conventional double voice coil speaker, a common capacitor is used and the capacitance of the capacitor is the same, so the outer voice coil has a higher frequency. A low frequency electrical signal will be input to the inner voice coil. As a result, an electric signal having a frequency unsuitable for each speaker is input.

In this way, the conventional double voice coil speaker has a circuit configuration that outputs an electric signal through a common capacitor to the outer voice coil and the inner voice coil. Therefore, as described above, the sound pressures are made uniform. And the input of an electric signal in a desired frequency band could not be achieved at the same time.

On the other hand, in the speaker system of the first embodiment, since the frequency characteristics of the electric signals input to the outer voice coil and the inner voice coil of the double voice coil speaker are different, the sound pressure is not limited by the frequency characteristics. The DC resistance of the outer voice coil and the inner voice coil can be set to align. Specifically, in the speaker system of the first embodiment, the DC resistance of the outer voice coil can be set to be smaller than the DC resistance of the inner voice coil. As a result, in the speaker system of the first embodiment, it is possible to make the sound pressure uniform and to input a signal in a desired frequency band at the same time.

Table 1 shows the magnitude relationship between the design values of the conventional double voice coil speaker described above and the design values of the outer voice coil (outer VC) and the inner voice coil (inner VC) in the speaker system of the first embodiment.

Although FIG. 1 describes an example in which a cap 108 covering the top of the first bobbin 102 is provided, the cap 108 may not be provided. FIG. 7 is a cross-sectional view of a modified example of the speaker according to the first embodiment. In FIG. 7, the first bobbin 102 of the speaker 100 has nothing to cover the opening at the top.

Further, in FIG. 1, an example in which the height of the cap 108 covering the top of the first bobbin 102 is lower than that of the main diaphragm 121 of the vibrating body 101 is described, but the cap 108 covering the top of the first bobbin 102 is described. The height may be higher than that of the main diaphragm 121 of the vibrating body 101. FIG. 8 is a cross-sectional view of a modified example of the speaker according to the first embodiment. In FIG. 8, the top of the cap 108 is higher than the top of the main diaphragm 121.

Further, although FIG. 3 describes an example in which the output unit 301 is connected to the speaker 100 by four signal lines, the output unit 301 may be connected to the speaker 100 by three signal lines. good. FIG. 9 is a circuit diagram showing a modified example of the electric circuit of the speaker system according to the first embodiment.

The input terminal 312 is connected from the output unit 301 by a wiring common to the speaker 100. The common wiring is branched in the speaker 100 and connected to the output terminal 322 and the output terminal 332.

Further, in the examples of FIGS. 5 and 6, an example in which the DC resistance of the outer voice coil is set to be smaller than the DC resistance of the inner voice coil is described, but the DC resistance of the outer voice coil is set to the inner voice coil. It may be equal to the DC resistance of.

In the speaker system of the first embodiment, FIG. 10 shows a frequency characteristic when the DC resistance of the outer voice coil is equal to the DC resistance of the inner voice coil. FIG. 10 is a graph showing an example of sound pressure and frequency characteristics in a modified example of the speaker system of the first embodiment. In FIG. 10, the horizontal axis represents the frequency. The vertical axis indicates the sound pressure level.

The frequency characteristic 1001 of FIG. 10 shows the frequency characteristic of the sound pressure generated by the outer voice coil when the electric signal is input without passing through the filter F303. The frequency characteristic 1002 indicates the frequency characteristic of the sound pressure generated by the inner voice coil when an electric signal is input without passing through the filter F302. The frequency characteristic 1011 indicates the frequency characteristic of the sound pressure generated by the outer voice coil when the electric signal passing through the filter F303 is input. The frequency characteristic 1012 indicates the frequency characteristic of the sound pressure generated by the inner voice coil when the electric signal passing through the filter F302 is input.

Comparing FIGS. 5 and 10, in the conventional double voice coil speaker, the frequency characteristic 512 of the sound pressure generated by the inner voice coil is the frequency characteristic 511 of the sound pressure generated by the outer voice coil. Although the sound pressure is higher, in the first embodiment, the frequency characteristic 1012 of the sound pressure generated by the inner voice coil and the frequency characteristic 1011 of the sound pressure generated by the outer voice coil are used. ， The sound pressure has a frequency characteristic with a small step.

Even if the DC resistance of the second voice coil 105 and the DC resistance of the first voice coil 103 have the same resistance value, the cutoff frequency of the electric signal input to the first voice coil 103 is set to the second voice coil 105. By making it higher than the cutoff frequency of the input electric signal, the difference in sound pressure between the first voice coil 103 (inner voice coil) and the second voice coil 105 (outer voice coil) can be reduced.

For example, by making the capacity of the capacitor C302 larger than the capacity of the capacitor C303, the cutoff frequency of the electric signal input to the second voice coil 105 is set to be higher than the cutoff frequency of the electric signal input to the first voice coil 103. Can be lowered.

Table 2 below shows the relationship between the design values of the conventional double voice coil speaker described above and the design values of the outer voice coil (outer VC) and the inner voice coil (inner VC) in the modified example of the first embodiment.

As described above, according to the speaker system of the first embodiment, in the double voice coil speaker in which two voice coils are connected to one vibrating body, two voice signals are input to the two voice coils to obtain two voice signals. It is possible to make the voice coil bear a desired frequency band and to make the total sound pressure of the speaker system uniform.

In the above description, the case where the two voice coils bear different frequency bands is described, but the two voice coils may be made to bear the same frequency band. In this case, by vibrating the two voice coils in the same frequency band and in the same phase, the inner edge and the outer edge of the annular vibrating body 101 can be vibrated equally, and the vibrating body 101 can be made to make a piston motion.

Specifically, the DC resistance value of each voice coil is set so as to correct the difference in the amount of amplitude due to the difference in the effective mass of the two voice coils, the stiffness of the support portion, and the magnetic energy supplied. Then, in order to align the phases in a wide frequency band with the DC resistance of the two voice coils set, the capacitance of each capacitor can be set so as to align the cutoff frequencies (by the filter) of the two voice coils.

Embodiment 2
In the second embodiment, the details when the top of the first bobbin 102 is covered with the cap 108 will be described. FIG. 11 is a cross-sectional view showing an example of the speaker according to the second embodiment. FIG. 11 shows half of the cross section of the double voice coil speaker. Therefore, in FIG. 11, the overall image of the cross-sectional view is line-symmetrical along the axis of symmetry indicated by the alternate long and short dash line. Further, the actual double voice coil speaker has a tubular three-dimensional shape centered on the axis of symmetry shown by the alternate long and short dash line in FIG.

As shown in FIG. 11, the first bobbin 102 around which the first voice coil 103 is wound is connected to the inner peripheral side of the ring-shaped main diaphragm 121. Further, a second bobbin 104 around which the second voice coil 105 is wound is connected to the outer peripheral side of the ring-shaped main diaphragm 121.

The outer circumference of the ring-shaped main diaphragm 121 is fixed to the frame 110 by the outer support portion 122.

A cap 108 is connected to one end of the tubular first bobbin 102, and a first voice coil 103 is connected to the other end of the first bobbin 102. A main diaphragm 121 is connected between the first voice coil 103 and one end of the first bobbin 102.

The back of the main diaphragm 121 on the outer peripheral side is connected to one end of the tubular second bobbin 104, and the second voice coil 105 is connected to the other end of the second bobbin 104.

The inner wall of the first bobbin 102 and the yoke 109 are connected by a flexible partition 111 (for example, a silicon adhesive), and the back space of the cap 108 becomes airtight.

Next, the operation will be described.
Electric signals are input to the first voice coil 103 and the second voice coil 105, respectively. Here, the first voice coil 103 wound around the first bobbin 102 and the second voice coil 105 wound around the second bobbin 104 have different magnetic fluxes in terms of diameter, mass, and magnetic gap. Therefore, even if the same electric signal is input to the first voice coil 103 and the second voice coil 105, the Lorentz force generated is different between the first voice coil 103 and the second voice coil 105.

As shown in FIG. 12, in the main diaphragm 121, the driving force of the first voice coil 103 is transmitted to the first bobbin 102 and transmitted to the inner circumference of the main diaphragm 121, and the second voice coil 105. The driving force of the above is transmitted to the second bobbin 104, and the force (1201) transmitted to the outer periphery of the main diaphragm 121 is superimposed and vibrates (1202). That is, two different forces are input to the diaphragm. FIG. 12 is a schematic cross-sectional view showing an example of vibration transmission of the double voice coil speaker.

The details of the vibration in the cap 108 will be described below.
Since the diameter of the cap 108 is smaller than the outer circumference of the main diaphragm 121, the cap 108 tends to vibrate in a higher frequency range than the second voice coil 105 (the outer circumference of the main diaphragm 121). That is, the cap 108 reproduces a frequency band higher than that of the main diaphragm 121. Further, since the area of the cap 108 is smaller than that of the main diaphragm 121, the shape is such that high frequencies can be easily reproduced.

With respect to the cap 108 that vibrates by the driving force of the first voice coil 103, the vibration caused by the second voice coil 105 becomes unnecessary vibration, and the vibration of the cap 108 becomes noise. There are two main types of noise. Here, the two types of noise will be described below as the first noise source and the second noise source, respectively.

The first noise source is the vibration of the second voice coil 105 in the same band. Specifically, the first noise source is in a band in which the inner peripheral characteristics and the outer peripheral characteristics of the main diaphragm 121 overlap. The vibration based on the first voice coil 103 of the cap 108 is mixed with the sound (disturbance) of the same band of the second voice coil 105, and the original vibration of the cap 108 cannot be performed.

The second noise source is the vibration of the second voice coil 105 in a band lower than the cap 108 reproduction band. Specifically, the second noise source is vibration having a frequency lower than the vibration band of the cap 108 of the second voice coil 105. Since the vibration has a large amplitude in the frequency band lower than the cap 108 reproduction band, the vibration in the cap 108 reproduction band is modulated by the Doppler effect, and the original vibration cannot be performed. This becomes noticeable when inputting all bands, for example, when playing music.

In order to suppress vibration transmission from these noise sources to the cap 108 and vibrate the cap 108 without being affected by noise, the outer circumference of the cap 108 is the first bobbin 102 around which the first voice coil 103 is wound. It is desirable that it is connected to one end (the end of the tubular portion) and is joined so as to pass only through the first bobbin 102. Here, a material that causes distortion at least equal to or less than that of the bobbin in the vibration axis direction of the first bobbin 102 may be further interposed.

Here, if the cap 108 is connected to the main diaphragm 121, the main diaphragm due to the sound of the second voice coil 105 in the same band as the vibration band of the cap 108 or the sound in the band lower than the vibration band of the cap 108. The deflection of 121 further affects the vibration of the cap 108. FIG. 13 is a cross-sectional view showing an example of a speaker in which the cap 108 is connected to the main diaphragm 121.

The vibration on the outer peripheral side of the main diaphragm 121 driven by the second voice coil 105 is also transmitted to the inner circumference of the diaphragm, and the vibration on the inner peripheral side of the main diaphragm 121 driven by the first voice coil 103. Interfere with.

Since the cap 108 is connected to one end (the tip of the tubular portion) of the first bobbin 102, the influence of vibration caused by the second voice coil 105, which is unnecessary vibration for the first bobbin 102, can be reduced.

Further, since the first bobbin 102 is connected to the top surface of the yoke 109 by a flexible partition 111 (such as a silicon adhesive), it is caused by the second voice coil 105 as shown in FIG. The transmission of vibration (1401) to the cap 108 can be suppressed. FIG. 14 is a cross-sectional view showing an example of vibration transmission of the speaker of the second embodiment.

Since the flexible partition 111 (silicon adhesive or the like) is airtight, the space on the back side of the main diaphragm 121 and the space on the back side of the cap 108 are blocked from communicating with each other. As a result, even if pressure fluctuation occurs in the space behind the ring-shaped main diaphragm 121 due to the vibration of the ring-shaped main diaphragm 121, it is not transmitted to the space behind the cap 108, and the vibration of the main diaphragm 121 The cap 108 can be vibrated without being affected by.

The influence of this pressure fluctuation will be described with reference to FIGS. 15 and 16.
FIG. 15 is a schematic diagram for explaining pressure fluctuation in a speaker without a partition. In FIG. 15, the pressure fluctuation of the space 1502 (second space) behind the main diaphragm 121 is transmitted to the cap 108 back space 1501 (first space), and the influence of the vibration of the main diaphragm 121 by the second voice coil 105 is capped. 108 receives and oscillates. Since the area of the main diaphragm 121 is larger than the area of the cap 108, the cap 108 is subjected to a pressure having an amplitude larger than the amplitude of the main diaphragm 121 due to Pascal's principle, which has a great influence.

FIG. 16 is a schematic diagram for explaining the pressure fluctuation in the speaker system of the second embodiment. Since the pressure fluctuation of the space 1602 (second space) behind the main diaphragm 121 is not transmitted to the cap 108 back space 1601 (first space), the vibration of the cap 108 is not affected by the vibration of the main diaphragm 121.

As described above, according to the speaker system of the second embodiment, the first space formed by the cap and the yoke and the second space formed by the main diaphragm 121 and the yoke are provided with a partition body. Since the pressure fluctuation in the two spaces is not transmitted to the first space, the vibration of the cap is not affected by the vibration of the main diaphragm 121.

The present invention is not limited to the above embodiment, and can be appropriately modified without departing from the spirit. For example, the annular shape is not limited to an annulus, but also includes an angular ring composed of polygons. Further, the cylindrical shape is not limited to a cylinder, and may be a square cylinder having a polygonal opening shape.

In the above embodiment, the voice coil is wound around the bobbin, but the voice coil may be directly connected to the vibrating body without passing through the bobbin. Along with this, the cap is connected to the first voice coil and covers the top of the first voice coil.

100 Speaker 101 Vibrating body 102 1st bobbin 103 1st voice coil 104 2nd bobbin 105 2nd voice coil 106 Magnet 107 Plate 108 Cap 109 York 110 Frame 111 Partition 121 Main diaphragm 122 Outer support 300 Speaker system 301 Output 311, 312 Input terminals 321, 322, 331, 332 Output terminals C302, C303 Condenser

Claims (4)

An annular vibrating body and
The first bobbin, which has a tubular shape and is physically connected to the vibrating body,
The first voice coil wound around the first bobbin and
A second bobbin having a tubular shape with a larger opening than the first bobbin and physically connected to the vibrating body,
The second voice coil wound around the second bobbin and
A speaker system including an output unit that is electrically connected to the first voice coil and the second voice coil and outputs electric signals having different frequency characteristics to the first voice coil and the second voice coil. The output unit suppresses the low frequency region with different cutoff frequencies and outputs the input electric signal to the first voice coil and the second voice coil.
The speaker system according to claim 1, wherein the cutoff frequency of the electric signal output to the first voice coil is higher than the cutoff frequency of the electric signal output to the second voice coil. The output unit outputs the input electric signal to the first voice coil and the second voice coil at different voltages.
The speaker system according to claim 1 or 2, wherein the voltage of the electric signal output to the second voice coil is higher than the voltage of the electric signal output to the first voice coil. A cap covering the opening of the first bobbin and
A yoke forming a space for accommodating the first bobbin, the first voice coil, the second bobbin, and the second voice coil.
The speaker system according to any one of claims 1 to 3, further comprising a first space formed by the cap and the yoke, and a partition body that partitions the vibrating body and the second space formed by the yoke.

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