JPH10341495

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DESCRIPTION JPH10341495
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
speaker system which is small in size and low in cost, and has an improved reproduction
capability in the low frequency range and an expanded reproduction range.
[0002]
[Prior Art] A speaker system, a subwoofer, etc. with low-frequency and small-volume, lowfrequency reproduction capability, in order to cope with high-quality, small-size and low-price AV
equipment accompanying digitalization in recent years. Is being desired. These AV devices
include not only single speaker systems and system stereos, but also vehicle-mounted stereos,
televisions, electronic musical instruments, PA devices and the like.
[0003]
Therefore, in order to enhance the low range reproduction capability, the applicant previously
filed Japanese Patent Application No. 8-102390, which will be described below with reference to
the drawings.
[0004]
08-05-2019
1
FIG. 9 is a block diagram of a speaker system.
In FIG. 9, reference numeral 51 denotes a first speaker, and 51a denotes a first cavity, which is a
closed type having an inner volume of 2.0 liters. Reference numeral 51b denotes a first speaker
unit which is a 14 cm diameter woofer housed in the first cavity 51a to constitute the first
speaker 51. The lowest resonance frequency f1 of the first speaker 51 is 62 Hz, and the
resonance sharpening The degree Q1 is 2.1.
[0005]
52 is a second speaker, 52a is a second cavity and is a closed type with an inner volume of 0.7
liter. Reference numeral 52b denotes a second speaker unit having a full range of 7 cm in
diameter, which is accommodated in the second cavity 52a to constitute the second speaker 52,
and the lowest resonance frequency ffr of the second speaker is about 140 Hz.
[0006]
The first speaker 51 and the second speaker 52 are driven together by separate power amplifiers
58 and 59 (bi-amplifier system). The crossover frequency fcr between the first speaker 51 and
the second speaker 52 is about 120 Hz, and 1.4 ≦ Q1 ≦ 10, f1 <ffr, f1 ≦ fcr ≦ f1 × {(Q12 +
1.2Q1) / (Q12) It is set up to satisfy the condition −2.5)} 0.5 × k, 1 ≦ k ≦ {(Q1 / (Q1−1.4))
2.5.
[0007]
FIG. 10 shows the frequency characteristics of the speaker system of the above configuration,
where B in the figure is the sound pressure frequency characteristic of the first speaker 51, C is
the sound pressure frequency characteristic of the second speaker 52, and A is the total sound of
these. Pressure frequency characteristics.
[0008]
However, in the above configuration, the sound pressure frequency characteristic B of the first
speaker 51 becomes single peak, and the bass reproduction band of the first speaker 51 can not
be broadened. There is a problem that the lowest resonance frequency of the second speaker 52
has to be set low.
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[0009]
The present invention solves the above-mentioned problems, and an object of the present
invention is to provide a speaker system that flattens a bass reproduction band of the first
speaker 51 over a wide band at a high sound pressure level.
[0010]
SUMMARY OF THE INVENTION In order to achieve the above object, a speaker system according
to the present invention comprises an electric circuit filter including a speaker in which a speaker
unit for low frequency band is housed in a cavity and having high frequency range attenuation
means for the speaker. Assuming that the lowest resonance frequency of the speaker is f1, the
resonance sharpness is Q1, the resonance frequency of the electric circuit filter is f2, and the
resonance sharpness is Q2, 1.4 ≦ Q1 ≦ 10, 0.7 ≦ Q2 ≦ 5 and f1 <f2 are satisfied.
[0011]
With this configuration, an increase in the sound pressure of the speaker occurs at the resonance
frequency f2 of the filter, and the frequency characteristic of the speaker system becomes a
trapezoidal characteristic with the resonance frequencies f1 and f2 as shoulders, and the bass
reproduction band can be expanded. it can.
[0012]
In addition, since the Q of the low frequency band resonance of the speaker is made extremely
high, the field section of the speaker unit, which is the most expensive, can be made very small,
so that the cost can be reduced.
[0013]
DESCRIPTION OF THE PREFERRED EMBODIMENTS The first invention of the present invention
relates to a first speaker in which a first speaker unit is housed in a first cavity, and a second
cavity driven together with the first speaker. An electric circuit filter having a second speaker
housing a second speaker unit and having high frequency range attenuation means for the first
speaker, wherein a minimum resonance frequency of the speaker is f1, a resonance sharpness is
Q1, and Assuming that the resonance frequency of the electric circuit filter is f2 and the
resonance sharpness is Q2, the conditions of 1.4 ≦ Q1 ≦ 10, 0.7 ≦ Q2 ≦ 5, f1 <f2 are satisfied,
and the bass reproduction band is Expansion and cost reduction can be achieved.
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[0014]
In the second invention of the present invention, a tubular or box-like acoustic tube of length L is
used as an acoustic radiation portion of the first speaker unit of the first speaker as the high
sound attenuation means of the first speaker. The minimum resonance frequency of the first
speaker is f1, the resonance sharpness is Q1, the minimum resonance frequency of the acoustic
tube is f3, the resonance sharpness is Q3, and the sound velocity is c, 1.4 ≦ Q1 ≦ 10, 0.7 ≦ Q3
≦ 5, f1 <f3, 0.7 × {c / (4 × f3)} ≦ L ≦ 1.4 × {c / (4 × f3)} are satisfied, In addition to the
operation of the first aspect of the invention, it is possible to realize a speaker system capable of
determining frequency characteristics with a small number of parameters.
[0015]
Further, according to a third invention of the present invention, as the high-frequency range
attenuation means of the first speaker, the voice coil bobbin of the center tip portion of the
diaphragm of the first speaker unit of the first speaker is via a spring-like elastic member. A
mechanical filter having high frequency range attenuation means for the speaker, wherein the
lowest resonance frequency of the speaker is f1, the resonance sharpness is Q1, the resonance
frequency of the mechanical filter is f4, and the resonance sharpness is Q4. , 1.4 ≦ Q1 ≦ 10, 0.7
≦ Q4 ≦ 5, f1 <f4, and in addition to the operation of the first invention, electric circuit parts are
used for the high-frequency range attenuation means It is possible to realize a speaker system
that can achieve low cost without having to
[0016]
Hereinafter, embodiments of the present invention will be described with reference to the
drawings.
(First Embodiment) FIG. 1 is a block diagram of a speaker system according to a first
embodiment of the present invention.
In FIG. 1, reference numeral 1 denotes a first speaker, whose external dimensions are 15 cm wide
× 15 cm high × 14 cm deep, and the plate thickness is 10 mm.
A first cavity 1a is a closed type having an inner volume of 2.0 liters.
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[0017]
A first speaker unit 1b is a 14 cm diameter woofer.
Impedance is 6 Ω, magnet size is 60 mm outside diameter × 32 mm inside diameter × 9 mm,
BL is 4.3, effective vibration radius is 47 mm, effective vibration mass is 28 g, single resonance
frequency is 30 Hz, mechanical resonance sharpness (Qm Is 8.0, and the voice coil DC resistance
is 4.8 Ω.
The voice coil is an 8-layer type with a diameter of 25 mm, has a very large inductance, and
attenuates the sound pressure level in the high range.
[0018]
The first speaker unit 1b is accommodated in the first cavity 1a to constitute the first speaker 1.
The lowest resonance frequency f1 of the first speaker 1 is 62 Hz, and the resonance sharpness
Q1 is 2.1. It is.
[0019]
A second speaker 2 has an outer dimension of 9 cm wide × 13 cm high × 11.5 cm deep, and a
plate thickness of 10 mm.
A second cavity 2a is a closed type having an inner volume of 0.5 liter.
[0020]
A second speaker unit 2b has a full range of 7 cm in diameter.
The impedance is 4Ω, the output sound pressure level is 80.5 dB / 1 W, and a sound pressure
level of 82 dB can be obtained at 1 W input voltage with 6 Ω impedance.
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[0021]
The second speaker unit 2b is accommodated in the second cavity 2a to constitute the second
speaker 2, and the minimum resonance frequency ffr of the second speaker 2 is about 150 Hz.
[0022]
In the present embodiment, the first speaker 1 and the second speaker 2 are driven together by
separate power amplifiers 8 and 9 provided with electric circuit filters 6 and 7 at the front stage
(bi-amplifier system).
Here, one configuration example of each of the electric circuit filters 6 and 7 is shown in FIG.
In FIG. 2, one is a low pass filter circuit 6 configured of a 10 kΩ resistor R1, R2, a 0.22 μF
capacitor C1, a 0.056 μF capacitor C2 and an operational amplifier OP1, and the other is a 5.6
kΩ resistor R3 10 kΩ A low pass filter circuit 7 is connected to the power amplifier 8, and a
high pass filter circuit 7 is connected to the power amplifier 9. The high pass filter circuit 7
comprises a resistor R 4, capacitors C 3 and C 4 of 0.22 μF, and an operational amplifier OP 2.
According to this configuration, the resonance frequency f2 of the low pass filter circuit 6 is 140
Hz, and the resonance sharpness Q2 is 1.3.
[0023]
In the present embodiment, the high pass filter circuit 7 is provided in the second speaker 2 to
perform bass region signal attenuation, but it is needless to say that it is not necessary to carry
out particularly.
Also, the frequency characteristics of each power amplifier 8, 9 are flat and the input sensitivity
and the maximum output power are also the same, and acoustically the same as when each
speaker is connected in parallel and driven by one power amplifier . In the embodiment of the
present embodiment, the polarities of the first speaker 1 and the second speaker 2 are reversed.
The crossover frequency fcr between the first speaker 1 and the second speaker 2 is set to about
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150 Hz.
[0024]
The operation and effects of the speaker system according to the present embodiment configured
as described above will be described below with reference to FIG. FIG. 3 is a frequency
characteristic diagram of the speaker system of the present embodiment.
[0025]
In FIG. 3, B is the sound pressure frequency characteristic of the first speaker 1, C is the sound
pressure frequency characteristic of the second speaker 2, A is the total sound pressure
frequency characteristic of these, and the input voltage is equivalent to 1 W with an impedance
of 6 Ω. is there. Also these properties are with infinite baffles.
[0026]
Since the resonance sharpness Q1 of the first speaker 1 is as high as 2.1, a high output sound
pressure level of about 83 dB can be obtained near 62 Hz of the lowest resonance frequency f1
as shown in B.
[0027]
The value of the resonance sharpness Q2 of the low-pass filter circuit 6 needs to be 0.7 or more
in order to prevent dips in the frequency characteristics at the crossover with the second speaker
2, and vice versa It becomes clear from simulation analysis and experiment that a peak appears
in the frequency characteristic when the value is extremely large, and it is assumed that about 5
is the upper limit.
[0028]
Further, in the present embodiment, since the conditions of 1.4 ≦ Q1 ≦ 10, 0.7 ≦ Q2 ≦ 5, and
f1 <f2 are set, the low-pass filter provided in the first speaker 1 is provided. The circuit 6 causes
an increase in sound pressure around 140 Hz at the same resonance frequency f2, and a sound
pressure increase of about 3 dB can be obtained compared to a speaker system not provided with
the low pass filter circuit 6.
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[0029]
On the other hand, the first speaker 1 of the present embodiment can expand the reproduction
band to 140 Hz or more as compared with the conventional first speaker 51, so the minimum
resonance frequency ffr of the second speaker 2 does not have to be lowered and is easy The
output sound pressure level can be increased to set the crossover frequency fcr between the first
speaker 1 and the second speaker 2 to about 150 Hz.
In the conventional speaker system, flat characteristics can not be obtained unless the crossover
frequency fcr is set to about 120 Hz.
[0030]
In the present embodiment, although one speaker unit is used for both the first speaker 1 and
the second speaker 2, a plurality of speaker units may be used.
[0031]
Further, in the present embodiment, although the second speaker 2 is of the closed type, it may
be of the bass reflex type.
In this case, if the antiresonance frequency is set lower than the crossover frequency and
designed near the lowest resonance frequency of the first speaker 1, the diaphragm amplitude in
the bass range of the second speaker unit 2b is reduced, and distortion is reduced. can do.
[0032]
Also, a so-called 3D combination in which one first speaker driven by a synthesized bass signal
from stereo L and R channels and a second speaker for each channel (total two) are combined
with this It can also be configured as a scheme.
Even if the number of channels is three or more, one first speaker can be combined with the
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second speaker of each channel number.
[0033]
Further, in the present embodiment, the polarities of the first speaker 1 and the second speaker 2
are reversed, but for example, there is a large distance difference between the first speaker 1 and
the second speaker 2. When the phase rotates around the crossover frequency, flat
characteristics are obtained when the polarity is the same.
[0034]
Further, in the present embodiment, the low pass filter circuit 6 and the high pass filter circuit 7
are configured of a resistor, a capacitor and an operational amplifier, but the present invention is
not limited to this.
[0035]
Needless to say, the present invention is not limited to the examples described above.
[0036]
Second Embodiment FIG. 4 is a block diagram of a speaker system according to a second
embodiment.
The 1st speaker 11 accommodates the 1st speaker unit 11b of aperture 14 cm woofer in the
cavity 11a of 2.0 liters of internal volume.
Then, on the front surface of the first speaker unit 11b, an acoustic tube 14 having a crosssectional dimension of a box with a width of 13 cm × 3 cm bent in three folds is attached.
The total length of the acoustic tube 14 is about 60 cm.
[0037]
The second speaker 12 is obtained by housing a second speaker unit 12b with a full diameter of
7 cm in a closed cavity 12a with an inner volume of 0.5 liter.
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[0038]
The first speaker unit 11b has an impedance of 6 Ω, a magnet size of 60 mm in diameter × 32
mm in diameter × 9 mm in thickness, a BL of 4.3, an effective vibration radius of 47 mm, an
effective vibration mass of 28 g, and a single lowest resonance frequency of 30 Hz The
mechanical resonance sharpness (Qm) is 8.0, the voice coil DC resistance is 4.8 Ω, and the voice
coil is an 8-layer type with a diameter of 25 mm.
[0039]
The second speaker unit 12 b has an impedance of 4Ω and an output sound pressure level of
80.5 dB / 1 W, and a sound pressure level of 82 dB can be obtained at 1 W input voltage with 6
Ω impedance.
[0040]
The lowest resonance frequency f1 of the first speaker 11 is 62 Hz, the resonance sharpness Q1
is 2.1, and the first resonance frequency of the acoustic tube 14 is 130 Hz.
The lowest resonance frequency ffr of the second speaker 12 is about 150 Hz.
[0041]
In the present embodiment, the first speaker 11 and the second speaker 12 are driven together
by separate power amplifiers 18 and 19 provided with electric circuit filters 16 and 17 at the
front stage (bi-amplifier system).
The electric circuit filter is a low pass filter circuit 16 that attenuates the high frequency range
signal of the first speaker 11 and a high pass filter circuit 17 that attenuates the low frequency
range signal of the second speaker 12.
In the present embodiment, although the high pass filter circuit 17 is provided in the second
speaker 12 to perform the bass region signal attenuation, it is not necessary to perform the
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attenuation particularly.
The frequency characteristics of the power amplifiers 18 and 19 are flat, and the input sensitivity
and the maximum output power are also the same. The crossover frequency fcr between the first
speaker 11 and the second speaker 12 is set to about 150 Hz.
[0042]
The operation and effects of the speaker system of the present embodiment configured as
described above will be described below with reference to FIG. FIG. 5 is a schematic frequency
characteristic of the speaker system of the present embodiment.
[0043]
In FIG. 5, B is a sound pressure frequency characteristic when there is no acoustic pipe 14 of the
first speaker 11, C is a sound pressure frequency characteristic of the second speaker 12, D is a
resonant sound pressure frequency characteristic of the acoustic pipe 14, E Is a sound pressure
frequency characteristic of the first speaker 11, and A is a total sound pressure frequency
characteristic of these.
[0044]
Since the resonance sharpness Q1 of the first speaker 11 is as high as 2.1, as shown in B, a high
sound pressure level can be obtained near 62 Hz of the lowest resonance frequency f1.
[0045]
In addition, since the acoustic tube 14 attached to the front surface of the speaker unit 11b of
the first speaker 11 causes resonance at the opening 15 of the acoustic tube 14 at a frequency
that is an odd multiple of 1⁄4 wavelength, The resonance frequency, that is, the lowest resonance
frequency f3 of the acoustic tube 14 can be easily set.
[0046]
Further, by using the acoustic tube 14, the frequency characteristic can be freely determined
only by the three parameters of the total length L of the acoustic tube 14, the cross-sectional
area of the acoustic tube 14, and the resonance sharpness Q3.
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[0047]
As for the value of the total length L of the acoustic tube 14, in the crossover with the second
speaker 12, a value in the range of 70% to 140% of the calculated value is used to prevent dips
and peaks from appearing in the frequency characteristics. It became clear from the experiment
that it is necessary.
[0048]
In addition, the value of the resonance sharpness Q3 can be adjusted by putting a sound
absorbing material or felt in the interior of the acoustic tube 14, and it is about 0.7 or more and
5 or so as with Q2 of the first embodiment. It is assumed that it is the upper limit.
[0049]
In the present embodiment, the lowest resonance frequency f3 of the acoustic tube 14 is 130 Hz
and the resonance sharpness Q3 is 3. As shown by D in FIG. 5, a high output sound pressure level
is obtained near 130 Hz of the lowest resonance frequency f3. You can get it.
[0050]
Furthermore, in the present embodiment, 1.4 ≦ Q1 ≦ 10, f1 <f3, 0.7 ≦ Q3 ≦ 5, 0.7 × {c / (4 ×
f3)} ≦ L ≦ 1.4 × {c The sound pressure frequency characteristic B of the first speaker 11 and
the acoustic tube attached to the first speaker 11 are set so as to satisfy the condition of / (4 ×
f3)} and (where c is the speed of sound). The resonance sound pressure frequency characteristic
D of 14 provides a trapezoidal characteristic E having the lowest resonance frequency f1 and the
lowest resonance frequency f3 as shoulders.
[0051]
On the other hand, since the reproduction band of the speaker 11 of this embodiment can be
expanded to 130 Hz or more as compared with the conventional first speaker 51, the minimum
resonance frequency ffr of the second speaker 12 does not have to be lowered and the output
sound can be easily output. The pressure level can be increased, and the crossover frequency fcr
between the first speaker 11 and the second speaker 12 can be set to about 150 Hz.
[0052]
In addition, although the 1st speaker 11 and the 2nd speaker 12 used one speaker unit in this
Embodiment, you may use several speaker units.
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[0053]
Further, in the present embodiment, although the second speaker 12 is of the closed type, it may
be of the bass reflex type.
In this case, if the antiresonance frequency is set lower than the crossover frequency and
designed around the lowest resonance frequency of the first speaker 11, the diaphragm
amplitude in the low frequency range of the second speaker unit 12b is reduced and distortion is
reduced. can do.
[0054]
Also, a so-called 3D combination in which one first speaker driven by a synthesized bass signal
from stereo L and R channels and a second speaker for each channel (total two) are combined
with this It can also be configured as a scheme.
Even if the number of channels is three or more, one first speaker can be combined with the
second speaker of each channel number.
[0055]
Also, in the present embodiment, the polarities of the first speaker 11 and the second speaker 12
are reversed, but there is a large distance difference between the first speaker and the second
speaker, for example, When the phase rotates around the over frequency, flat characteristics are
obtained when the polarity is the same.
[0056]
Further, in the present embodiment, the shape of the acoustic tube 14 is formed by bending the
box several folds, but it may be tubular.
[0057]
Needless to say, the present invention is not limited to the examples described above.
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[0058]
Third Embodiment FIG. 6 is a block diagram of a speaker system according to a third
embodiment of the present invention, which is substantially the same as the speaker system
according to the first embodiment.
The difference is in the first speaker unit 21b.
[0059]
Therefore, the first speaker unit 21b is accommodated in the first cavity 21a to constitute the
first speaker 21. The lowest resonance frequency f1 of the first speaker 1 is 62 Hz, and the
resonance sharpness Q1 is 2.1. It is.
[0060]
The second speaker unit 22b is accommodated in the second cavity 22a to constitute the second
speaker 22, and the minimum resonance frequency ffr of the second speaker 22 is about 150 Hz.
[0061]
FIG. 7 is a structural view of the speaker unit according to the third embodiment of the present
invention.
31 is an edge, 32 is a diaphragm, 33 is a dust cap, 34 is a damper, 35 is a frame, 36 is a top
plate, 37 is a magnet, 38 is a plate with a center pole, 39 is a spring-like elastic member, resin
fibers And the thickness is 0.075 mm.
４０はボイスコイルボビン、４１はボイスコイルである。
The diameter of the elastic member 39 is the same as that of the voice coil bobbin 40, and four
bellows of about 1 mm are provided.
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In the above configuration, when the center tip of the diaphragm 32 is coupled to the voice coil
bobbin 40 via the spring-like elastic member 39, it acts as a mechanical filter, and its equivalent
circuit is as shown in FIG.
8, F is a driving force, Cc is a compliance of the vibration system, Cm is a compliance of the
mechanical filter by the elastic member 39, M is a vibration mass on the voice coil 41 side, and m
is a vibration mass on the diaphragm 32 side.
In the present embodiment, the resonance frequency f4 of the mechanical filter is set to 140 Hz,
and the resonance sharpness Q4 is set to 2.5.
[0062]
The value of Q4 can be adjusted by changing the internal loss of the elastic member 39, and the
upper limit is set to about 0.7 or more and 5 as in the case of Q2 of the first embodiment.
Internal loss can be varied by the thickness and type of fiber, and the resin impregnation
concentration.
[0063]
In the embodiment configured as described above, the speaker according to Embodiment 1 is set
because the conditions of 1.4 ≦ Q1 ≦ 10, 0.7 ≦ Q4 ≦ 5, and f1 <f4 are set. As in the system,
the sound pressure frequency characteristic of the first speaker 21 is as shown in B of FIG. 3, and
it is possible to obtain trapezoidal characteristics with the lowest resonance frequency f1 and the
resonance frequency f4 of the mechanical filter as shoulders.
[0064]
Further, by using a mechanical filter, it is possible to reduce the cost without the need for
electrical circuit parts.
[0065]
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Further, since the reproduction band of the speaker 21 of the present embodiment can be
expanded to 140 Hz or more as compared with the conventional first speaker 51, the minimum
resonance frequency ffr of the second speaker 22 does not have to be lowered and the output
sound can be easily output. The pressure level can be increased, and the crossover frequency fcr
between the first speaker 21 and the second speaker 22 can be set to about 150 Hz.
[0066]
In the present embodiment, although one speaker unit is used for both the first speaker 21 and
the second speaker 22, a plurality of speaker units may be used.
[0067]
Further, in the present embodiment, the second speaker 22 is a closed type, but it may be a bass
reflex type.
In this case, if the antiresonance frequency is set lower than the crossover frequency and
designed near the lowest resonance frequency of the first speaker 21, the diaphragm amplitude
in the low frequency range of the second speaker unit 22b is reduced and distortion is reduced.
can do.
[0068]
Also, a so-called 3D combination in which one first speaker driven by a synthesized bass signal
from stereo L and R channels and a second speaker for each channel (total two) are combined
with this It can also be configured as a scheme.
Even if the number of channels is three or more, one first speaker can be combined with the
second speaker of each channel number.
[0069]
Further, in the present embodiment, the polarities of the first speaker 21 and the second speaker
22 are reversed, but there is a large distance difference between the first speaker and the second
speaker, for example, When the phase rotates around the over frequency, flat characteristics are
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obtained when the polarity is the same.
[0070]
Needless to say, the present invention is not limited to the examples described above.
[0071]
As described above, according to the present invention, since the resonance sharpness of the first
speaker is very high, the output sound pressure level in the low tone range can be significantly
increased, and the first speaker can be further enhanced. On the other hand, the bass
reproduction band can be expanded by using a high resonance sharpness electric circuit filter
having a high range attenuation means.
[0072]
Further, by attaching an acoustic tube to the acoustic radiation part of the speaker unit of the
first speaker, the frequency characteristic can be determined with a small number of parameters,
and the bass reproduction band can be expanded.
[0073]
Further, by using a mechanical filter with high resonance sharpness having high-tone range
attenuation means for the first speaker, it is possible to achieve cost reduction and expand the
bass reproduction band without requiring electric circuit parts. .
[0074]
In addition, since the Q of the low frequency band resonance of the speaker is made extremely
high, the field section of the speaker unit, which is the most expensive, can be made very small,
so that the cost can be reduced.
[0075]
In addition, since the bass reproduction band of the first speaker can be expanded, and there is
no need to lower the lowest resonance frequency of the second speaker, the output sound
pressure level in the middle to high range can be easily increased.
[0076]
Brief description of the drawings
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[0077]
1 is a block diagram of the speaker system according to the first embodiment of the present
invention
[0078]
Fig. 2 Configuration diagram of the electric circuit filter in the same speaker system
[0079]
Fig. 3 Frequency characteristics of the speaker system
[0080]
4 is a configuration diagram of a speaker system according to a second embodiment of the
present invention
[0081]
Fig. 5 Frequency characteristics of the same speaker system
[0082]
6 is a configuration diagram of a speaker system according to a third embodiment of the present
invention
[0083]
Fig. 7 Structure of the speaker unit of the speaker system
[0084]
Figure 8 Equivalent circuit diagram of mechanical filter of the speaker unit
[0085]
Fig. 9 A block diagram of the conventional speaker system
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[0086]
Fig. 10 Frequency characteristics of the conventional speaker system
[0087]
Explanation of sign
[0088]
Reference Signs List 1 first speaker 1a first cavity 1b first speaker unit 2 second speaker 2a
second cavity 2b second speaker unit 6 low pass filter circuit 7 high pass filter circuit 8, 9 power
amplifier
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