JPH11146486A - Speaker system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a speaker system that can raise a sound pressure level in a low-frequency range by specifying an impedance of an impedance compensation circuit. SOLUTION: An impedance compensation circuit of an impedance Zc, which turns electric impedance of a speaker system into a constant-resistance in order to prevent a decline of efficiency, is inserted serially in the second voice coil. At this time, the impedance compensation circuit decides the impedance Zc so that the electric impedance as the speaker system becomes the constant- resistance when a bass-reflex system cabinet is used. That is, this impedance compensation circuit becomes what an equation indicates in a formulaic expression. In the equation, each of L1 and L2 indicates inductance and each of C1 and C2 indicates capacity and each of rc1 and rc2 indicates resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speaker system capable of increasing the sound pressure level in a low frequency range by making the electrical impedance of a speaker system constant resistance when the cabinet is of a bass reflex type or Kelton type. It is about.

That is, the present invention provides a bass reflex type cabinet, a double voice coil speaker unit,
A speaker system having an impedance compensation circuit for making the input impedance constant, or a Kelton type cabinet, a double voice coil speaker unit, and an impedance compensation circuit for making the input impedance constant resistance. Related to speaker systems.

[0003]

2. Description of the Related Art A conventional speaker system will be described with reference to FIGS. 7, 8 and 9. FIG. FIG. 7 is disclosed, for example, by Watkins (WH Watkins "N
ew Loudspeaker with Extended Bass ”Audio, Dec. 19
74, pp. 38-46) A configuration example of a conventional speaker system in which a double voice coil is used to improve sound radiation efficiency in a low frequency range.

In FIG. 7, reference numerals 11 and 12 denote signal input terminals to a speaker, reference numeral 20 denotes a double voice coil speaker unit, reference numeral 21 denotes a first voice coil, reference numeral 22 denotes a second voice coil, and reference numeral 23 denotes a voice coil. The bobbin 30 is an impedance compensation circuit for making the electrical impedance of the speaker system constant.

Next, the operation of the conventional speaker system will be described with reference to FIGS. FIG.
FIG. 3 is a diagram showing an electrical impedance characteristic of a conventional speaker system. FIG. 9 is a diagram showing sound pressure level characteristics of a conventional speaker system.

Generally, when the impedance compensation circuit 30 is not provided, that is, when only the first voice coil 21 is used, the electric impedance of the speaker unit 20 becomes a parallel resonance circuit, and as shown in FIG. ) Of the lowest resonance frequency f ₀
A characteristic peak occurs in the vicinity.

Therefore, the current flowing through the first voice coil 21 decreases near the lowest resonance frequency f ₀ , and the efficiency of sound radiated from the speaker decreases.

In FIG. 7, a series circuit composed of a coil L and a capacitor C is inserted in series into the second voice coil 22.
The electric impedance is always constant (constant resistance) by connecting a series resonance circuit to which the resistance of the second voice coil 22 is added in parallel with the first voice coil 21.
To improve sound radiation efficiency.

FIG. 9 shows a change in the sound pressure level depending on the presence or absence of the impedance compensating circuit in a low sound range. As can be seen from FIG.
By increasing the impedance to a constant resistance using, a rise in sound pressure level near the lowest resonance frequency f ₀ , that is, a rise in sound radiation efficiency can be seen. This magnitude can reach several dB depending on conditions.

[0010]

In the conventional speaker system described above, the impedance compensation circuit 30 is used.
Is constituted by a series resonance circuit including a coil L, a capacitor C, and a resistance of the second voice coil 22, the constant resistance can be realized because the electric impedance of the first voice coil 21 is different from that of the parallel resonance circuit. Only if it becomes. In other words, the playback system is limited to a closed cabinet or a system in which a speaker unit is used alone. Therefore, the conventional speaker system shown in FIG. 7 has a problem that it cannot be applied to a bass reflex cabinet currently used generally or other systems.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem. When a cabinet is of a bass reflex type or a Kelton type, the electric impedance of a speaker system is made to have a constant resistance. It is an object of the present invention to obtain a speaker system capable of increasing a sound pressure level.

[0012]

A speaker system according to the present invention comprises a bass reflex type cabinet, a double voice coil speaker unit having first and second voice coils attached to the cabinet and to which an input signal is applied. A sound port provided in the cabinet, and an impedance compensation circuit inserted between the input terminal to which the input signal is applied and the second voice coil to make the input impedance constant resistance, The inductances of the circuit elements of the impedance compensation circuit are L ₁ and L ₂ , the capacitances are C ₁ and C ₂ , the resistance is r _C1 ,
When r _C2 is set, the impedance Zc of the impedance compensating circuit is represented by Expression (1).

Further, in the speaker system according to the present invention, a resonance angular frequency of the double voice coil speaker unit is ω ₀ , an equivalent mass of the double voice coil speaker unit is m ₀ , The equivalent mechanical compliance is C ₀ , the electrical sharpness of the double voice coil speaker unit is Q ₀ , the mechanical sharpness of the double voice coil speaker unit is Q _m , and the second voice coil speaker unit is the second voice coil speaker unit. the ratio of the force factor of the voice coil alpha, the bass reflex volume by compliance of the air within the cabinet C _b, viewed equivalent mechanical resistance due to the volume in the bass reflex type cabinet r _b, from the double voice coil speaker unit The equivalent mass of the sound port is _ml ,
When the equivalent mechanical resistance of the sound port viewed from the heavy voice coil speaker unit is r _l , the resistance of the first voice coil is R _V1 , and the resistance of the second voice coil is R _V2 , β = m _l / m ₀ , γ _b = C ₀ / C _b , Q _b = ω ₀ m ₀ /
r _b, the condition _{Q l = ω 0 m 0 /} r l, constants of respective circuit elements of the resistor R _V2 and the impedance compensation circuit of the second voice coil relationship of equation (3) to (9) It is what it was.

A speaker system according to the present invention comprises a bass reflex type cabinet, a double voice coil speaker unit having first and second voice coils attached to the cabinet and to which an input signal is applied.
An acoustic port provided in the cabinet, and an impedance compensating circuit inserted between the input terminal to which the input signal is applied and the second voice coil to make the input impedance a constant resistance, When the inductances, which are the circuit elements of the impedance compensating circuit, are L ₁ and L ₂ and the capacitances are C ₁ and C ₂ , the impedance Zc of the impedance compensating circuit is represented by Expression (2).

A speaker system according to the present invention includes a Kelton type cabinet, a double voice coil speaker unit having first and second voice coils attached to the cabinet and to which an input signal is applied.
An acoustic port provided in the cabinet, and an impedance compensating circuit inserted between the input terminal to which the input signal is applied and the second voice coil to make the input impedance a constant resistance, When the inductances of the circuit elements of the impedance compensating circuit are L ₁ and L ₂ , the capacitances are C ₁ and C ₂ , and the resistances are r _C1 and r _C2 , the impedance Zc of the impedance compensating circuit is expressed by equation (1). Things.

Further, in the speaker system according to the present invention, the resonance angle frequency of the double voice coil speaker unit is ω ₀ , the equivalent mass of the double voice coil speaker unit is m ₀ , The equivalent mechanical compliance is C ₀ , the electrical sharpness of the double voice coil speaker unit is Q ₀ , the mechanical sharpness of the double voice coil speaker unit is Q _m , and the second voice coil speaker unit is the second voice coil speaker unit. the ratio of the force factor of the voice coil alpha, the double voice coil speaker unit rear space by the equivalent mechanical compliance of C _b, the equivalent mechanical resistance due to the air chamber r _b of the double voice coil speaker unit rear space, the 2 Equivalent mechanical compliance with double air coil speaker unit front air chamber The impedance is C _f , the equivalent mechanical resistance by the front air chamber of the double voice coil speaker unit is r _f , the equivalent mass of the sound port viewed from the double voice coil speaker unit is _ml , and the double voice coil speaker unit is The equivalent mechanical resistance of the sound port as viewed from above is r _l , and the resistance of the first voice coil is R
_V1 , when the resistance of the second voice coil is R _V2 , β = _ml / m ₀ , γ _b = C _b / C ₀ , γ _l = C ₁ / C ₀ , Q
_{b = ω 0 m 0 / r} b, Q f = ω 0 m 0 / r f, Q l = ω 0 m 0 / r l
The resistance R _V2 of the second voice coil and the constant of each circuit element of the impedance compensating circuit satisfy the relations of Expressions (14) to (20).

A speaker system according to the present invention includes a Kelton type cabinet, a double voice coil speaker unit having first and second voice coils attached to the cabinet and to which an input signal is applied.
An acoustic port provided in the cabinet, and an impedance compensating circuit inserted between the input terminal to which the input signal is applied and the second voice coil to make the input impedance a constant resistance, When the inductances, which are the circuit elements of the impedance compensating circuit, are L ₁ and L ₂ and the capacitances are C ₁ and C ₂ , the impedance Zc of the impedance compensating circuit is represented by Expression (2).

Furthermore, the speaker system according to the present invention, wherein the impedance compensation circuit comprises: a first series circuit of the inductance L ₁ and the capacitor C _1, is connected to the first series circuit, a resistor r _C1 A parallel circuit in which a resistor r _C2 and a third series circuit having an inductance L ₂ are connected in parallel to a second series circuit having a capacity C ₂ .

Further, in the speaker system according to the present invention, the impedance compensation circuit is connected to the series circuit of the inductance L ₁ and the capacitor C ₁ and the parallel circuit of the inductance L ₂ and the capacitor C ₂ . It is composed of

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIGS. 1 to 5 show a speaker system according to Embodiment 1 of the present invention.
This will be described with reference to FIG. FIG. 1 is a diagram showing a configuration of a speaker system according to Embodiment 1 of the present invention. In the drawings, the same reference numerals indicate the same or corresponding parts.

In FIG. 1, reference numerals 11 and 12 denote signal input terminals to speakers, reference numeral 20 denotes a double voice coil speaker unit, reference numeral 21 denotes a first voice coil, reference numeral 22 denotes a second voice coil, and reference numeral 23 denotes a voice coil. Bobbin 30A is an impedance compensating circuit for making the electrical impedance of the speaker system a constant resistance;
Denotes an acoustic port, and 100 denotes a bass reflex type cabinet.

Here, the "bass reflex type cabinet" refers to a cabinet 100 having a structure in which a rear space of the speaker unit 20 is acoustically coupled to an acoustic port 40 for emitting sound to the outside, as shown in FIG. It is.

Next, the operation of the first embodiment will be described with reference to FIGS. FIG. 2 is a diagram showing electric impedance characteristics of the bass reflex speaker system according to Embodiment 1 of the present invention.

[0024] Conventionally, the electrical impedance of bass reflex speaker system results in generally two peaks before and after the anti-resonance frequency f _r as shown in Figure 2. This system corresponds to the case where only the first voice coil 21 is used in FIG. 1, and the electrical impedance of the speaker unit 20 (speaker system) is the anti-resonance frequency _fr.
, Two peaks occur before and after the input signal, so that the input current decreases in response to the increase in the impedance, and the efficiency of sound radiated from the speaker decreases.

Therefore, in order to prevent this reduction in efficiency, an impedance compensating circuit 30A having an impedance Zc for converting the electrical impedance of the speaker system into a constant resistance is inserted in series with the second voice coil 22.

Here, as the impedance compensating circuit 30A, the impedance Zc is determined so that the electric impedance of the speaker system becomes a constant resistance when the bass reflex cabinet 100 is used. That is, since the electric impedance of the first voice coil 21 is shown in FIG. 2, each element is selected so as to cancel the peak of the characteristic. This impedance compensation circuit 30A
Generally, it is represented in FIG. 3 and expressed in the following mathematical expression (1).

[0027]

(Equation 7)

In the above equation (1), the resistances r _C1 and r _C2
Is generally smaller than jωL ₂ , 1 / (jωC ₂ ). Therefore, substantially the same effect can be obtained even if the circuit in FIG. 3 is approximately replaced with the circuit in FIG. The circuit of FIG.
In mathematical expression, the following expression (2) is used.

[0029]

(Equation 8)

Here, each element constant of the impedance compensating circuit 30A depends on the bass reflex type cabinet 100 to be used.
Depends on the dimensions of the loudspeaker system, the condition for completely making the electrical impedance of the speaker system constant resistance is uniquely determined.

When the bass reflex type cabinet 100 is used, the resonance angular frequency of the double voice coil speaker unit is “ω ₀ ”, the equivalent mass of the double voice coil speaker unit is “m ₀ ”, and the double voice coil speaker unit is The equivalent mechanical compliance is “C ₀ ”, and the electrical sharpness of the double voice coil speaker unit is “Q
₀ ”, the mechanical sharpness of the double voice coil speaker unit is“ Q _m ”, and the second voice coil
, The force coefficient ratio of the voice coil 22 is “α”, the air compliance by the volume in the bass reflex cabinet 100 is “C _b ”, the equivalent mechanical resistance by the volume in the bass reflex cabinet 100 is “r _b ”, and the speaker unit The equivalent mass of the acoustic port 40 as viewed from the speaker unit 20 is “m _l ”, the equivalent mechanical resistance of the acoustic port 40 as viewed from the speaker unit 20 is “r _l ”, and the first voice coil 2
When the resistance of the first voice coil 22 is "R _V1 ", the second voice coil 22
R _V2 , the inductance L ₁ of the compensation circuit element,
L ₂ , capacitance C ₁ , C ₂ , resistance r _C1 , r _C2 are calculated by the following equation (3).
To (9).

[0032]

(Equation 9)

Where β, γ _b , Q _b , Q
_l is as shown in the following formulas (10) to (13).

[0034]

(Equation 10)

FIG. 5 is a diagram showing calculation results comparing changes in sound pressure level characteristics and changes in electric impedance characteristics depending on the presence or absence of the impedance compensating circuit 30A in the low frequency range. Referring to FIG. 5, the impedance compensation circuit 3
Electrical impedance depending 0A, together are the constant resistance (electrical impedance characteristic curve → thick line in electrical impedance characteristic curve of the thin line), anti-resonance frequency f the sound pressure level characteristics of that sound pressure levels before and after rises (thin line _r Curve →
It can be seen that the sound pressure level characteristic curve of the bold line).

As described above, the speaker system using the double voice coil speaker unit according to the first embodiment is composed of one double voice coil speaker unit 2 attached to the bass reflex type cabinet 100.
0 and a dedicated impedance compensating circuit 30A, so that the input impedance of the speaker system can be made constant.

Therefore, the input to the speaker system is always supplied at a constant level, which has the effect of improving the sound radiation efficiency near the anti-resonance frequency of the bass reflex speaker system.

Embodiment 2 Embodiment 2 A speaker system according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 6 is a diagram showing a configuration of a speaker system according to Embodiment 2 of the present invention.

In FIG. 6, reference numerals 11 and 12 denote signal input terminals to a speaker, reference numeral 20 denotes a double voice coil speaker unit, reference numeral 21 denotes a first voice coil, reference numeral 22 denotes a second voice coil, and reference numeral 23 denotes a voice coil. Bobbin 30B is an impedance compensating circuit for making the electrical impedance of the speaker system constant resistance, 40B
Is an acoustic port, and 200 is a Kelton type cabinet.

Here, the "Kelton type cabinet" means that the rear space of the speaker unit 20 mounted inside is sealed and the front space of the speaker unit 20 is connected to the acoustic port 40 for emitting sound to the outside. A cabinet 200 having an acoustically coupled structure.

Next, the operation will be described. Electrical impedance characteristics of the Kelton type speaker system, like the bass reflex rise to two peaks before and after the anti-resonance frequency f _r as shown in Figure 2.

Here, the anti-resonance frequency f in the Kelton system
_r is an acoustic resonance frequency determined by the acoustic space at the front of the speaker unit 20 and the acoustic port 40.

Therefore, this method is the first in FIG.
And the electric impedance of the speaker unit 20 (speaker system) has two peaks before and after the anti-resonance frequency _fr , so that the input current corresponds to the rise of the impedance. And the efficiency of the sound emitted from the speaker decreases.

Therefore, in order to prevent the sound efficiency from lowering, an impedance compensating circuit 30 B for making the electric impedance of the speaker system a constant resistance is inserted in series with the second voice coil 22.

Here, when the Kelton system cabinet 200 is used as the impedance compensating circuit 30B, the impedance Zc is determined so that the electric impedance of the speaker system becomes a constant resistance.

This impedance compensating circuit 30B is generally represented in FIG. 3 similarly to the case of the bass reflex type speaker system, and the mathematical expression of the impedance Zc is the same as the above-mentioned expression (1).

Further, regarding the above equation (1), the resistance r
_C1, r _C2 is, jωL _2, 1 / generally small compared to (j [omega] C _2). Therefore, substantially the same effect can be obtained even if the circuit in FIG. 3 is approximately replaced with the circuit in FIG. That is, the circuit of FIG. 4 is the same as the above equation (2) in mathematical expression.

Here, each element constant of the impedance compensating circuit 30B depends on the Kelton type cabinet 200 used.
Depends on the dimensions of the loudspeaker system, the condition for completely making the electrical impedance of the speaker system constant resistance is uniquely determined.

When the Kelton type cabinet 200 is used, the resonance angular frequency of the double voice coil speaker unit is “ω ₀ ”, the equivalent mass of the double voice coil speaker unit is “m ₀ ”, and the double voice coil speaker unit is The equivalent mechanical compliance is “C ₀ ”, and the electrical sharpness of the double voice coil speaker unit is “Q
₀ ”, the mechanical sharpness of the double voice coil speaker unit is“ Q _m ”, and the second voice coil
"Α" the ratio of the force factor of the voice coil 22 of the "C _b" the equivalent mechanical compliance by the speaker unit at the rear space, "r _b" the equivalent mechanical resistance due to the air chamber of the speaker unit at the rear space, the speaker unit front "C _f" the equivalent mechanical compliance with air chambers, "r _f" the equivalent mechanical resistance due to the speaker unit front air chamber, the equivalent mass of the acoustic port 40 as viewed from the speaker unit 20 "m _l", from the speaker unit 20 The equivalent mechanical resistance of the acoustic port 40 seen is " _rl ",
When the resistance of the voice coil 21 is “R _V1 ”, the resistance R _{V2 of} the second voice coil 22, the inductances L ₁ and L _{2 of the} compensating circuit elements, the capacitances C ₁ and C ₂ , and the resistances r _C1 and r _{C C2} is obtained from the following equations (14) to (20).

[0050]

[Equation 11]

Where β, γ _b , γ _f , Q _b ,
Q _f and Q _l are as in the following equations (21) to (26).

[0052]

(Equation 12)

As described above, the speaker system using the double voice coil speaker unit according to the second embodiment is composed of one double voice coil speaker unit 2 mounted on the Kelton type cabinet 200.
0 and a dedicated impedance compensating circuit 30B, so that the input impedance of the speaker system can be made constant.

Therefore, the input to the speaker system is always supplied at a constant level, and the sound radiation efficiency near the anti-resonance frequency of the Kelton speaker system is improved.

[0055]

According to the speaker system of the present invention,
As described above, a bass reflex cabinet, a double voice coil speaker unit having first and second voice coils attached to the cabinet and to which an input signal is applied, an acoustic port provided in the cabinet, An impedance compensating circuit inserted between the input terminal to which the input signal is applied and the second voice coil so as to make the impedance a constant resistance, wherein the inductance which is a circuit element of the impedance compensating circuit is L _{When 1} , L ₂ , capacitances are C ₁ and C ₂ , and resistances are r _C1 and r _C2 , the impedance Zc of the impedance compensating circuit is expressed by the equation (1). The resistance can be made constant, and the sound radiation efficiency near the anti-resonance frequency can be improved. There is an effect that kill.

As described above, in the speaker system according to the present invention, the resonance angular frequency of the double voice coil speaker unit is ω ₀ , the equivalent mass of the double voice coil speaker unit is m ₀ , and the double voice coil speaker unit is m ₀ , The equivalent mechanical compliance of the voice coil speaker unit is C ₀ , the electrical sharpness of the double voice coil speaker unit is Q ₀ , the mechanical sharpness of the double voice coil speaker unit is Q _m , the first voice coil the ratio of the force factor of the second voice coil α with respect to, the bass reflex compliance with C _b of air by volume in the cabinet, the bass reflex equivalent mechanical resistance due to the volume of the cabinet r _b, the double voice coil The equivalent mass of the sound port viewed from the speaker unit is _ml , When the equivalent mechanical resistance of the sound port viewed from the voice coil speaker unit is r _l , the resistance of the first voice coil is R _V1 , and the resistance of the second voice coil is R _V2 , β = m ₁ / m ₀ , γ _b = C ₀ /
_{C b, Q b = ω 0} m 0 / r b, the condition _{Q l = ω 0 m 0 /} r l, constants of respective circuit elements of the resistor R _V2 and the impedance compensation circuit of the second voice coil Since the relations of Expressions (3) to (9) are satisfied, the input impedance of the speaker system can be made constant resistance, and the effect of improving the sound radiation efficiency near the anti-resonance frequency can be obtained.

As described above, the speaker system according to the present invention comprises: a bass reflex type cabinet; a double voice coil speaker unit having first and second voice coils attached to the cabinet and to which an input signal is applied; An acoustic port provided in the cabinet, and an impedance compensating circuit inserted between the input terminal to which the input signal is applied and the second voice coil to make the input impedance a constant resistance, When the inductances L ₁ and L ₂ and the capacitances C ₁ and C ₂ are the circuit elements of the impedance compensating circuit, the impedance Zc of the impedance compensating circuit is expressed by equation (2). Capacitance can be made constant resistance,
There is an effect that the sound radiation efficiency near the anti-resonance frequency can be improved.

As described above, the speaker system according to the present invention comprises a Kelton type cabinet, a double voice coil speaker unit having first and second voice coils attached to the cabinet and to which an input signal is applied. An acoustic port provided in the cabinet, and an impedance compensating circuit inserted between the input terminal to which the input signal is applied and the second voice coil to make the input impedance a constant resistance, When the inductances of the circuit elements of the impedance compensating circuit are L ₁ and L ₂ , the capacitances are C ₁ and C ₂ , and the resistances are r _C1 and r _C2 , the impedance Zc of the impedance compensating circuit is expressed by equation (1). Therefore, the input impedance of the speaker system can be made constant resistance. An effect that it is possible to improve the sound radiation efficiency near the anti-resonance frequency.

As described above, in the speaker system according to the present invention, the resonance angular frequency of the double voice coil speaker unit is ω ₀ , the equivalent mass of the double voice coil speaker unit is m ₀ , and the double voice coil speaker unit is m ₀ , The equivalent mechanical compliance of the voice coil speaker unit is C ₀ , the electrical sharpness of the double voice coil speaker unit is Q ₀ , the mechanical sharpness of the double voice coil speaker unit is Q _m , the first voice coil The ratio of the force coefficient of the second voice coil to α is α, the equivalent mechanical compliance by the rear space of the double voice coil speaker unit is C _b , and the equivalent mechanical resistance by the air chamber in the rear space of the double voice coil speaker unit is Cb. r _b, the double voice coil speaker unit front air chamber The equivalent mechanical compliance is C _f , the equivalent mechanical resistance due to the front air chamber of the double voice coil speaker unit is r _f , and the equivalent mass of the sound port viewed from the double voice coil speaker unit is m.
_l , the equivalent mechanical resistance of the sound port as viewed from the double voice coil speaker unit is r _l , the resistance of the first voice coil is R _V1 , and the resistance of the second voice coil is R
When the _{V2 is, β = m l / m 0} , γ b = C b / C 0, γ l
= C ₁ / C ₀ , Q _b = ω ₀ m ₀ / r _b , Q _f = ω ₀ m ₀ / r _f , Q
_{Under the} condition of _l = ω ₀ m ₀ / r _l , the resistance R _V2 of the second voice coil and the constants of each circuit element of the impedance compensating circuit have the relationship of the equations (14) to (20).
The input impedance of the speaker system can be made constant resistance, and the sound radiation efficiency near the anti-resonance frequency can be improved.

As described above, the speaker system according to the present invention includes a Kelton type cabinet, a double voice coil speaker unit having first and second voice coils attached to the cabinet and to which an input signal is applied. An acoustic port provided in the cabinet, and an impedance compensating circuit inserted between the input terminal to which the input signal is applied and the second voice coil to make the input impedance a constant resistance, When the inductances L ₁ and L ₂ and the capacitances C ₁ and C ₂ are the circuit elements of the impedance compensating circuit, the impedance Zc of the impedance compensating circuit is expressed by equation (2). Capacitance can be made constant resistance,
There is an effect that the sound radiation efficiency near the anti-resonance frequency can be improved.

Further, in the speaker system according to the present invention, as described above, the impedance compensating circuit is connected to the first series circuit having the inductance L ₁ and the capacitance C ₁ and the first series circuit. , Resistance r
The input impedance as a speaker system is made to be a constant resistance because it is composed of a parallel circuit in which a resistor r _C2 and a third series circuit of an inductance L ₂ are connected in parallel to a second series circuit of _C1 and a capacitor C ₂ . Therefore, the sound radiation efficiency near the anti-resonance frequency can be improved.

[0062] Further, the speaker system according to the present invention, as described above, wherein the impedance compensation circuit comprises a series circuit of the inductance L ₁ and the capacitor C _1, is connected to the series circuit, the inductance L ₂ and the capacitance since being composed of a parallel circuit of C _2, the input mosquito impedance as the speaker system can be fixed resistance, an effect that it is possible to improve the sound radiation efficiency near the anti-resonance frequency.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a bass reflex speaker system according to Embodiment 1 of the present invention.

FIG. 2 is a diagram showing electric impedance characteristics of the bass reflex speaker system according to Embodiment 1 of the present invention.

FIG. 3 is a diagram showing an impedance compensation circuit of the bass reflex speaker system according to Embodiment 1 of the present invention.

FIG. 4 is a diagram showing another impedance compensation circuit of the bass reflex speaker system according to Embodiment 1 of the present invention.

FIG. 5 is a diagram comparing changes in a sound pressure level characteristic and an electrical impedance characteristic in the bass reflex type speaker system according to Embodiment 1 of the present invention depending on the presence or absence of a compensation circuit in a low frequency range.

FIG. 6 is a diagram showing a configuration of a Kelton speaker system according to Embodiment 2 of the present invention.

FIG. 7 is a diagram showing a configuration of a conventional speaker system.

FIG. 8 is a diagram showing electric impedance characteristics of a conventional speaker system.

FIG. 9 is a diagram showing a sound pressure level characteristic of a conventional speaker system.

[Explanation of symbols]

11, 12 signal input terminal, 20 double voice coil speaker unit, 21 first voice coil, 22
2nd voice coil, 23 bobbins, 30A, 30B
Impedance compensation circuit, 40 sound ports, 100
Bass reflex cabinet, 200 Kelton cabinet.

Claims (8)

[Claims] 1. A bass reflex type cabinet, a double voice coil speaker unit attached to the cabinet and having first and second voice coils to which an input signal is applied, an acoustic port provided in the cabinet, An impedance compensating circuit inserted between the input terminal to which the input signal is applied and the second voice coil to make the impedance a constant resistance, wherein an inductance which is a circuit element of the impedance compensating circuit is L ₁ , L ₂ , capacitance C ₁ , C ₂ , resistance r _C1 , r _C2
Wherein the impedance Zc of the impedance compensation circuit is expressed by the following equation. (Equation 1) 2. The resonance frequency of the double voice coil speaker unit is ω ₀ , the equivalent mass of the double voice coil speaker unit is m ₀ , the equivalent mechanical compliance of the double voice coil speaker unit is C ₀ , The electrical sharpness of the double voice coil speaker unit is Q ₀ , the mechanical sharpness of the double voice coil speaker unit is Q _m , and the ratio of the force coefficient of the second voice coil to the first voice coil is Q. alpha, the bass reflex compliance with C _b of air by volume in the cabinet, the bass reflex equivalent mechanical resistance due to the volume of the cabinet r _b, the equivalent mass of the acoustic port looking from the double voice coil speaker unit m
_l , the equivalent mechanical resistance of the sound port as viewed from the double voice coil speaker unit is r _l , the resistance of the first voice coil is R _V1 , and the resistance of the second voice coil is R
When the _{V2 is, β = m l / m 0} , γ b = C 0 / C b, Q b
= Ω ₀ m ₀ / r _b and Q _l = ω ₀ m ₀ / r _l , the resistance R _V2 of the second voice coil and the constant of each circuit element of the impedance compensation circuit have the following relationship. The speaker system according to claim 1, wherein: (Equation 2) 3. A bass reflex cabinet, a double voice coil speaker unit attached to the cabinet and having first and second voice coils to which an input signal is applied, an acoustic port provided in the cabinet, An impedance compensating circuit inserted between the input terminal to which the input signal is applied and the second voice coil to make the impedance a constant resistance, wherein an inductance which is a circuit element of the impedance compensating circuit is L A speaker system wherein the impedance Zc of the impedance compensation circuit is represented by the following equation, where ₁ , L ₂ and capacitances are C ₁ and C ₂ . (Equation 3) 4. A skeleton cabinet, a double voice coil speaker unit attached to the cabinet and having first and second voice coils to which an input signal is applied, an audio port provided in the cabinet, An impedance compensating circuit inserted between the input terminal to which the input signal is applied and the second voice coil to make the impedance a constant resistance, wherein an inductance which is a circuit element of the impedance compensating circuit is L ₁ , L ₂ , capacitance C ₁ , C ₂ , resistance r _C1 , r _C2
Wherein the impedance Zc of the impedance compensation circuit is expressed by the following equation. (Equation 4) 5. The resonance frequency of the double voice coil speaker unit is ω ₀ , the equivalent mass of the double voice coil speaker unit is m ₀ , the equivalent mechanical compliance of the double voice coil speaker unit is C ₀ , The electrical sharpness of the double voice coil speaker unit is Q ₀ , the mechanical sharpness of the double voice coil speaker unit is Q _m , and the ratio of the force coefficient of the second voice coil to the first voice coil is Q. α, the equivalent mechanical compliance due to the rear space of the double voice coil speaker unit is C _b , the equivalent mechanical resistance due to the air chamber in the rear space of the double voice coil speaker unit is r _b , the front air of the double voice coil speaker unit the equivalent mechanical compliance by the chamber C _f, the double voice coil spin The equivalent mechanical resistance due to the car unit front air chamber r _f, the equivalent mass of the acoustic port looking from double voice coil speaker units m _l, the equivalent mechanical resistance of the acoustic port looking from the double voice coil speaker unit _rl , when the resistance of the first voice coil is R _V1 and the resistance of the second voice coil is R _V2 , β = _ml / m ₀ , γ _b = C _b / C ₀ , γ _l = C _l /
_{C 0, Q b = ω 0} m 0 / r b, Q f = ω 0 m 0 / r f, Q l = ω 0
m ₀ / the r _l as a condition, a speaker system according to claim 4, wherein the constants of the circuit elements of the resistor R _V2 and the impedance compensation circuit of the second voice coil is characterized in that it is in the following relationship. (Equation 5) 6. A skeleton cabinet, a double voice coil speaker unit attached to the cabinet and having first and second voice coils to which an input signal is applied, an audio port provided in the cabinet, An impedance compensating circuit inserted between the input terminal to which the input signal is applied and the second voice coil to make the impedance a constant resistance, wherein an inductance which is a circuit element of the impedance compensating circuit is L A speaker system wherein the impedance Zc of the impedance compensation circuit is represented by the following equation, where ₁ , L ₂ and capacitances are C ₁ and C ₂ . (Equation 6) 7. The impedance compensating circuit is connected to a first series circuit having an inductance L ₁ and a capacitor C _{1 and} a second series circuit having a resistor r _C1 and a capacitor C ₂ . 5. The speaker system according to claim 1, wherein the circuit comprises a parallel circuit in which a third series circuit having a resistance r _C2 and an inductance L ₂ is connected in parallel. 8. The impedance compensating circuit is connected to a series circuit of an inductance L ₁ and a capacitance C ₁ and is connected to the series circuit.
Speaker system according to claim 3 or 6, wherein it is composed of ₂ and a parallel circuit of capacitance C _2.