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JPH077789

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This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
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DESCRIPTION JPH077789
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
cone type speaker for reproducing easy-to-hear sound quality by reducing the peak of a cone
type diaphragm or making an appropriate dip in sound pressure frequency characteristics. .
[0002]
2. Description of the Related Art In recent years, in order to reproduce a high-quality digital
music source comfortably, it is desirable to reduce the peak of the sound pressure frequency
characteristics of a cone type speaker and to eliminate the offensive sound as much as possible. .
In addition to reducing the peak, it is also desirable to control the sound pressure frequency
characteristics of the cone-shaped speaker so that the sound quality is easy to hear.
[0003]
By the way, the sound pressure frequency characteristic peak of the cone type speaker is often
generated due to the high frequency resonance of the cone type diaphragm.
[0004]
Therefore, first, high frequency resonance will be described.
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FIG. 10 shows a computer simulation model of a conventional cone-shaped speaker, which is a
non-deformed state in which no signal is input. FIG. 11 shows a computer simulation vibration
mode when a signal of the first high-order resonance frequency is input. It can be seen that the
outermost periphery of the cone-shaped diaphragm is subjected to the largest resonance
deformation. That is, the antinode of resonance is the outermost periphery of the cone-shaped
diaphragm.
[0005]
FIG. 12 shows a computer simulation vibration mode when a signal of the second high band
resonance frequency is input, but the number of antinodes of the resonance deformation is
increased to two, and the large portion of the resonance deformation moves inward from the
outermost circumference It is slightly closer to the outer periphery of the cone-shaped
diaphragm. Similarly, FIG. 13 shows a computer simulation vibration mode in the case of the
third high band resonance, but the number of antinodes in the resonance deformation is three,
and the large deformation part is to the far inner side of the cone type diaphragm. You can see
that you are moving.
[0006]
As described above, the high frequency resonance is a resonance in which a standing wave is
applied to a cone-shaped diaphragm, and a peak is generated in the sound pressure frequency
characteristic. In addition, the number of antinodes of the resonant deformation increases as the
high-frequency resonance becomes higher, and the portion where the resonant deformation is
large moves to the inner peripheral side of the cone-shaped diaphragm.
[0007]
Hereinafter, a conventional cone-type loudspeaker for reducing high-frequency resonance peaks
will be described with reference to the drawings. FIG. 14 is a sketch of a conventional 18 cmdiameter cone-shaped speaker in which high-frequency resonance peaks are reduced.
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[0008]
The cone-shaped diaphragm 51 is attached to the voice coil bobbin 54, and its outer periphery is
supported by an edge 56 attached to the frame 58. Also, a dust cap 55 is attached to the inner
peripheral portion. The voice coil 53 is held in the magnetic gap of the field section 59 by a
damper 57 attached to the frame 58. For the edge 56, a material such as foamed butyl rubber or
an elastomer having a large internal loss, that is, a high viscosity, is used to reduce the highfrequency resonance peak.
[0009]
With this configuration, as described above, the outermost periphery of the cone-shaped
diaphragm 51 moves best in the first order high-frequency resonance, so that a large internal
loss of the edge 56, that is, a viscous force is received. That is, the first high band resonance
mode is damped, and the first high band resonance peak is reduced.
[0010]
However, in the above-described conventional configuration, it is difficult to damp the mode
higher than the second high band resonance because the portion having a large resonance
deformation is not on the outermost periphery of the cone-shaped diaphragm. As a result, there
is a problem that the second and higher high-frequency resonance peaks can not be reduced.
[0011]
In addition, it is known that if you make appropriate dips in the mid-to-high range of the sound
pressure frequency characteristics and reduce the level of the mid-to-high range to some extent,
the sound quality will be easy to hear. Such control is very difficult, and an equalizer circuit using
a coil and a capacitor had to be added.
[0012]
FIG. 9 shows a computer simulation sound pressure frequency characteristic graph (solid line) of
a conventional cone-shaped speaker, although the peak of the first high band resonance around
1.6 kHz is low, the second high band around 3.2 kHz It can be seen that the peak of the
resonance remains high.
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[0013]
An object of the present invention is to solve the above-mentioned conventional problems, and it
is an object of the present invention to provide a cone type speaker which can reduce peaks and
freely make dips at any frequency.
[0014]
SUMMARY OF THE INVENTION In order to achieve the above object, a cone type loudspeaker
according to the present invention has a mechanical resonator attached near the junction of a
cone type diaphragm and a voice coil bobbin.
[0015]
According to this configuration, the mechanical resonator resonates near the natural resonance
frequency of the mechanical resonator, and the drive energy of the voice coil is absorbed by the
mechanical resonator.
Therefore, the amplitude of the cone-shaped diaphragm decreases in the vicinity of the
frequency, and a dip can be made in the sound pressure frequency characteristic.
If the natural resonance frequency of the mechanical resonator is set near the peak frequency,
the peak is reduced.
[0016]
EXAMPLES Examples of the present invention will be described below.
First, a first embodiment of the present invention will be described with reference to the
drawings.
FIG. 1 is a sketch of an embodiment of a cone-type speaker according to the first aspect of the
present invention.
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[0017]
This cone type speaker has an aperture of 18 cm.
A cone-shaped diaphragm 1 is made of a polypropylene sheet having a thickness of 0.4 mm.
Reference numeral 2 is a mechanical resonator, 3 is a voice coil, an aperture 32 mm, 4 is a voice
coil bobbin, a material is a polyamide resin with a thickness of 0.075 mm, 5 is a dust cap with a
diameter of 57 mm, and a material is a cloth with a thickness of 0.4 mm. 6 is an edge, the
material is an elastomer resin having a thickness of 0.2 mm, 7 is a damper, 8 is a frame, 9 is a
field portion, and all except the mechanical resonator 2 are illustrated in FIG. It is the same as the
conventional one shown.
[0018]
The mechanical resonator 2 comprises a mass (mass) portion 2 a and a suspension portion 2 b,
and is attached to the top of the voice coil bobbin 4. The material of the mechanical resonator 2
is a polypropylene resin for injection.
[0019]
The mass portion 2a is conical and has a hole with a diameter of 10 mm for air circulation open
at its center and a thickness of 1.5 mm. The mass portion 2a is conical in order to make it move
integrally without deformation at high frequencies. The suspension portion 2b is a roll having a
radius of curvature of 2.8 mm and a width of 4 mm and a thickness of 0.27 mm. In this way, the
natural resonance frequency of the mechanical resonator 2 is set to be around 3.2 kHz, which is
the second high-order resonance frequency.
[0020]
The dust cap 5 is attached to the inner peripheral portion of the cone-shaped diaphragm 1 so as
to cover the mechanical resonator 2.
[0021]
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The operation of the cone-type speaker of the present embodiment configured as described
above will be described below.
[0022]
When a signal near 3.2 kHz of the second high-order resonance frequency is added, since the
natural resonance frequency of the mechanical resonator 2 is set to around 3.2 kHz, the mass
portion 2 a vibrates violently to cause resonance.
Then, since the drive energy transmitted from the voice coil bobbin 4 is absorbed by the
mechanical resonator 2, the amplitude of the cone-shaped diaphragm 1 decreases around 3.2
kHz, which is the second higher resonance frequency, to 3.2 kHz. Nearby peaks are reduced.
[0023]
In addition, since the mechanical resonator 2 is covered by the dust cap 5, its natural resonance
sound is not emitted, and a very high-quality reproduced sound can be obtained.
[0024]
The operation of the cone-type loudspeaker of the present embodiment configured as described
above, which has been demonstrated by computer simulation, will be described below.
[0025]
FIG. 7 is a computer simulation model diagram of the cone type speaker of this embodiment.
FIG. 8 is a computer simulation vibration mode diagram in the case where a signal of 3.2 kHz,
which is the second high-order resonance frequency, is added to this simulation model as in the
case of FIG.
From this, it is obvious that the mechanical resonator is vigorously oscillating and that the
amplitude of the cone-shaped diaphragm is so small that the resonance mode as shown in FIG.
12 is hardly visible.
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[0026]
FIG. 6 shows a computer simulation sound pressure frequency characteristic diagram (solid line)
of the cone type speaker of the above embodiment.
It can be seen that the second high band resonance peak near 3.2 kHz, which is the highest level
in FIG. 9, is collapsed and greatly reduced in FIG.
[0027]
As described above, according to the present embodiment, the mechanical resonator 2 is
attached to the top of the voice coil bobbin 4 (that is, in the vicinity of the junction between the
cone type diaphragm 1 and the voice coil bobbin 4). By setting the cone-type diaphragm 1 near
an arbitrary high-resonance frequency, the mechanical resonator 2 resonates near the highfrequency resonance frequency, so that the drive energy of the voice coil 3 is absorbed there, the
cone-type The amplitude of the diaphragm 1 can be reduced to reduce the peak of the high
resonance frequency thereof.
[0028]
Although in the present embodiment the material of the mechanical resonator 2 is
polypropylene, it is needless to say that it may be made of paper, metal or any other material.
Also, although the mechanical resonator 2 is composed of the mass portion 2a and the
suspension portion 2b, even if it is not divided into two parts like this, for example, an integral
flat plate or other shape may be used. .
[0029]
Further, in the present embodiment, the natural resonance frequency of the mechanical
resonator 2 is set near the second high band resonance frequency, but if it is desired to reduce
another peak, it may be set near the peak frequency. In addition, in order to obtain sound quality
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that is easy to hear, it is possible to set a natural resonance frequency by targeting an offensive
frequency band and create a dip in sound pressure frequency characteristics.
[0030]
Further, in the present embodiment, the mechanical resonator 2 is attached to the top of the
voice coil bobbin 4, but this is attached near the base of the cone type diaphragm 1 or below the
junction of the cone type diaphragm 1 of the voice coil bobbin 4 (the damper 7 You may attach
to the upper side etc. Moreover, although the hole was provided in the center part of the
mechanical resonator 2 in the present Example, of course, it does not matter even if there is no
hole.
[0031]
Next, a second embodiment of the present invention will be described with reference to FIG. FIG.
2 is an enlarged view of a central portion of a cone-shaped speaker according to a second
embodiment of the present invention. The aperture of the speaker is also 18 cm. The difference
from the first embodiment is only in the mechanical resonator portion, and the other
configuration is completely the same, so the description thereof will be omitted.
[0032]
The first mechanical resonator 12 comprises a mass portion 12a and a suspension portion 12b,
and is provided on the inner peripheral side of the mounting position. The second mechanical
resonator 20 is composed of a mass portion 20a and a suspension portion 20b, and is provided
on the outer peripheral side of the mounting position. These materials are polypropylene resins
for injection.
[0033]
The first mechanical resonator has the same shape and size as the first embodiment. The second
mass portion 20a has a cone shape and a diameter of 50 mm and a thickness of 0.9 mm, and the
second suspension portion 20b has a curvature radius of 1.7 mm and a width of 3 mm and a
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thickness of 0.4 mm.
[0034]
Thus, the natural resonance frequency of the first mechanical resonator 12 is around 3.2 kHz,
which is the second high-order resonance frequency, and the natural resonance frequency of the
second mechanical resonator 20 is the third high. The frequency is set to be around 4.4 kHz
which is the area resonance frequency.
[0035]
Then, the dust cap 15 is attached to the inner peripheral portion of the cone-shaped diaphragm
11 so as to cover the first mechanical resonator 12 and the second mechanical resonator 20.
[0036]
The operation of the cone-type speaker according to the present embodiment configured as
described above will be described below.
[0037]
The operation in the case where a signal near 3.2 kHz, which is the second higher resonance
frequency, is added is as described in the first embodiment.
Similarly to the operation when a signal near 4.4 kHz, which is the third high-order resonance
frequency, is added, the second mechanical resonator 20 has its natural resonance frequency set
to about 4.4 kHz. The 2's mass portion 20a vibrates violently to cause resonance.
Then, since the driving energy of the voice coil 13 is absorbed by the second mechanical
resonator 20, the amplitude of the cone-shaped diaphragm 11 decreases around 4.4 kHz, which
is the third higher resonance frequency, Nearby peaks are reduced.
That is, the peaks of both the second and third high band resonances are reduced.
[0038]
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As described above, according to the present embodiment, the first mechanical resonator 12 and
the second mechanical resonator 20 in which respective natural resonance frequencies are set in
the vicinity of two arbitrary peak frequencies of the cone-shaped diaphragm 11 are The first
mechanical resonator 12 and the second mechanical resonator 20 resonate near the respective
peak frequencies by providing them on the inner peripheral side and the outer peripheral side of
the mounting position, so that the drive energy of the voice coil 13 is there As it is absorbed, the
amplitude of the cone diaphragm 11 can be reduced to reduce any two peaks.
[0039]
In the present embodiment, the natural resonance frequencies of the first and second mechanical
resonators 12 and 20 are set near the second and third high-order resonance frequencies, but
they are set near an arbitrary frequency according to the purpose. It goes without saying that it
is also possible.
[0040]
Next, a third embodiment of the present invention will be described with reference to FIG.
FIG. 3 is an enlarged view of a central portion of a cone type speaker according to a third
embodiment of the present invention.
The loudspeaker of this embodiment also has an aperture of 18 cm, and the mechanical
resonator 22 is the same in material and shape as the first embodiment. The natural resonance
frequency is also set around 3.2 kHz.
[0041]
The difference is that the cone-shaped diaphragm 21 and the mechanical resonator 22 are
integrally formed, and the other configurations are exactly the same as in the first embodiment.
The cone-shaped diaphragm 21 is made of polypropylene for injection, has a thickness of 0.4
mm, and has a peak of the second high-frequency resonance around 3.2 kHz.
[0042]
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The operation and effects of the cone-type speaker of the present embodiment configured as
described above are exactly the same as the first embodiment, but in the present embodiment,
the cone-type diaphragm 21 and the mechanical resonator 22 are integrally formed. Since it is
molded, it also has the effect that manufacture of a cone type speaker can be made easy.
[0043]
Next, a fourth embodiment of the present invention will be described with reference to FIG.
FIG. 4 is an enlarged view of a central portion of a cone-shaped speaker according to a fourth
embodiment of the present invention, except that the viscoelastic material 40 is newly attached
to the mechanical resonator 32. The configuration is the same as in the first embodiment.
[0044]
The viscoelastic material 40 is butyl rubber having a thickness of 1 mm, and is attached to the
suspension portion 32b in a divided manner.
[0045]
The operation and effects of the cone type speaker of the present embodiment configured as
described above are basically the same as the first embodiment, but in the present embodiment,
the visco-elastic material 40 is attached to the mechanical resonator 32. Therefore, the Q of the
natural resonance of the mechanical resonator 32 is reduced, and the width of the frequency for
absorbing the drive energy of the voice coil 33 is increased.
[0046]
That is, since the peak can be reduced even if the natural resonance frequency of the mechanical
resonator 32 deviates somewhat from the peak frequency of the cone-shaped diaphragm 31, the
mass production variation of the characteristics of the cone-shaped speaker can be reduced. .
[0047]
In addition, since a broad dip can be created on the sound pressure frequency characteristic over
a wide band, the control of the sound quality is further facilitated.
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[0048]
Finally, a fifth embodiment of the present invention will be described with reference to FIG.
FIG. 5 is a sketch of the cone type speaker according to the fifth embodiment of the present
invention, but the absence of the dust cap, the mechanical resonator 42 and the mechanical
resonator 42 at the base of the cone type diaphragm 41. It has the same configuration as that in
the first embodiment except that it is attached.
[0049]
In the present embodiment, the mass portion 42a of the mechanical resonator 42 is domeshaped and has no hole in the center.
The mechanical resonator 42 doubles as a dust cap.
The material is inexpensive styrene resin.
[0050]
The operation and effects of the cone-type speaker of the present embodiment configured as
described above are the same as those of the first embodiment, but the dust cap is not separately
required in the present embodiment, so the cone-type speaker can be easily manufactured. It also
has the effect of
[0051]
Although the mechanical resonator 42 is attached to the base of the cone-shaped diaphragm 41
in this embodiment, it may be attached to the top of the voice coil bobbin 44 or the like.
[0052]
As described above, according to the cone-type speaker of the present invention, the mechanical
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resonator is attached in the vicinity of the junction between the cone-shaped diaphragm and the
voice coil bobbin, so that the characteristic resonance frequency is near the natural resonance
frequency of the mechanical resonator. The mechanical resonator resonates.
Therefore, since the drive energy of the voice coil is absorbed there and the amplitude of the
cone type diaphragm is reduced, it is possible to reduce the peak and freely make dip in the
sound pressure frequency characteristic.
[0053]
Further, by providing two mechanical resonators having different natural resonance frequencies
respectively on the inner and outer peripheral sides of the mounting position, the peaks of any
two frequencies of the cone-shaped diaphragm can be reduced or the like. Can.
[0054]
In addition, by integrally forming the cone-shaped diaphragm and the mechanical resonator, the
manufacture of a cone-shaped speaker can be facilitated.
[0055]
Also, by attaching a visco-elastic material to the mechanical resonator, the Q of the natural
resonance of the mechanical resonator is lowered, so the peak is displayed even if the natural
resonance frequency of the mechanical resonator is somewhat offset from the peak frequency of
the cone type diaphragm It is possible to reduce the mass production variation of the
characteristics of the cone type speaker.
Furthermore, control of sound pressure frequency characteristics is facilitated.
[0056]
In addition, since the mechanical resonator doubles as the dust cap, the manufacture of the cone
type speaker becomes easy.
[0057]
As described above, the present invention can provide a cone-type speaker with easy-to-listen
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sound quality, and has great practical value.
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