JPH11146480A - Speaker system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain improvement in sound radiation efficiency by solving the efficiency degradation of a speaker caused by the increase of an impedance to occur before and after an anti-resonance frequency concerning a speaker system provided with the cabinet of a passive radiator type or kelton type equipped with a passive radiator. SOLUTION: This system is provided with plural double voice coil speaker units 20, for which first voice coils 21 and second voice coils 22 are parallelly connected while respectively matching their polarities, attached to a cabinet 50 of the passive radiator type or kelton type equipped with the passive radiator and a single impedance compensating circuit 10 serially connected to the said parallelly connected plural second voice coils 22 for making an input impedance as the speaker system into constant 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, and more particularly to a speaker system in which a plurality of dual voice coil speaker units are mounted on a passive radiator type or Kelton type cabinet provided with a passive radiator.

[0002]

FIG. 7 is disclosed by Watkins.
(WH Watkins "New Loudspeaker with Extended Bass"
Audio, Dec. 1974, PP. 38-46) This is an example of a conventional speaker configuration in which a double voice coil is used to improve the sound radiation efficiency in the low frequency range. In FIG. 7, 100
Is a signal input terminal to a speaker, 20 is a dual voice coil speaker unit, 21 is a first voice coil, 2
Reference numeral 2 denotes a second voice coil, 25 denotes a bobbin for attaching the voice coil, and 10 denotes a compensation circuit for converting the electrical impedance of the speaker to a constant resistance, and is configured by a series circuit of an inductance L and a capacitance C.

In general, when there is no compensation circuit 10, 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. A characteristic peak occurs near the frequency f ₀ . Therefore, the current flowing through the first voice coil 21 decreases near f ₀ , and the efficiency of sound radiated from the speaker decreases. Therefore, in FIG. 7, a series circuit including an inductance L and a capacitance C is inserted in series with the second voice coil 22, and a series resonance circuit to which the resistance of the second voice coil 22 is added is connected in parallel with the first voice coil 21. Constant electrical impedance (constant resistance) by connecting
To improve sound radiation efficiency.

FIG. 9 shows a change in sound pressure level depending on the presence or absence of an impedance compensation circuit in a low sound range. It increases the sound pressure level near the lowest resonance frequency f ₀ by the constant resistance of the impedance using the compensation circuit as can be seen from Figure 9, that is, increase of the sound radiation efficiency is seen. This effect reaches several dB depending on the condition.

FIG. 10 is an extension of the conventional speaker configuration shown in FIG. 7 to a speaker system using a plurality of double voice coil speaker units. In FIG. 10, 10-1,..., 10-i,.
0-n is an impedance compensating circuit, 20-1, ..., 20-
, 20-n are dual voice coil speaker units, 21-1, ..., 21-i, ..., 21-n are first voice coils, 22-1, ... , 22-i, ..., 22-n are second voice coils, 25-1, ..., 25-i, ..., 2
5-n is a bobbin for attaching a voice coil. The same or corresponding parts as those in FIG. 7 are denoted by the same reference numerals.

By the way, in order to realize a constant resistance in a conventional speaker configuration, one impedance compensation circuit is required for one double voice coil speaker unit. Therefore, in FIG. 10, the impedance compensation circuits 10-1,..., 10-i,... Corresponding to the respective speaker units 20-1,..., 20-i,.
.. 10-n is required.

[0007]

In the conventional speaker system configured as described above, when a plurality of speaker units are used as shown in FIG. 10, an impedance compensation circuit corresponding to each unit is required. Therefore, a speaker system using a plurality of units requires a plurality of impedance compensation circuits. Therefore, it is generally expensive, and the space inside the cabinet is occupied, and there is a problem that a sufficient volume for bass reproduction cannot be secured.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has been made to solve the above-mentioned problem. It is an object of the present invention to provide a speaker system of a Kelton type cabinet provided with a radiator type or a passive radiator.

[0009]

SUMMARY OF THE INVENTION In view of the above objects, the present invention comprises a passive radiator type or Kelton type cabinet provided with a passive radiator, and first and second voice coils, respectively. A plurality of dual voice coil speaker units having the same specifications and a single impedance compensating circuit for making the electrical impedance of the speaker system a constant resistance, wherein the first voice coil is a first voice coil;
Are connected in parallel with the same polarity between the voice coils, and the second voice coil is connected in parallel with the same polarity between the second voice coils, and the input signal is directly applied to each first voice coil. The speaker system is characterized in that an input signal through the impedance compensation circuit is applied to each second voice coil.

Further, according to the present invention, the inductances of the circuit elements of the impedance compensation circuit are L ₁ and L ₂ , and the capacitance is C.
_{When 1} , C ₂ , C ₃ and the resistances are r _C1 and r _C2 , the impedance Z _{C of the} impedance compensation circuit is

[0011]

(Equation 5)

The speaker system is characterized by being represented by the following.

Further, according to the present invention, the inductances of the circuit elements of the impedance compensation circuit are L ₁ and L ₂ , and the capacitance is C.
_{When 1} , C ₂ and C ₃ are set, the impedance Z _{C of the} impedance compensation circuit becomes

[0014]

(Equation 6)

The speaker system is characterized by being represented by the following.

Further, the present invention relates to a single radiator type cabinet, wherein the cabinet is a passive radiator type cabinet, and the resonance seen from the first voice coil under the condition that the second voice coil is opened. The angular frequency is ω ₀ , the equivalent mass is m ₀ , the compliance is C ₀ , the electrical sharpness is Q ₀ , the mechanical sharpness is Q _m , the first
Α is the ratio of the force coefficient of the second voice coil to the voice coil, n is the number of double voice coil speaker units to be used, and the air due to the volume in the passive radiator type cabinet viewed from the single speaker unit disposed. compliance and C _b, the mechanical resistance r _b, likewise the equivalent mass of the passive radiator m _p as seen from a single speaker unit, an equivalent mechanical resistance r _p, the equivalent mechanical compliance C _p, the inductance of the impedance compensation circuit L ₁ , L ₂ , capacitance C ₁ , C ₂ , C ₃ , resistance r _C1 ,
When r _C2 and the resistances of the first and second voice coils are R _V1 and R _V2 , respectively, R _V2 and each element constant of the impedance compensation circuit are approximately equal.

[0017]

(Equation 7)

The speaker system according to the present invention is characterized by the following relationship.

The present invention is also a Kelton type cabinet in which the cabinet is provided with a passive radiator, and has a sealed air chamber at the rear of the speaker unit and an air chamber connected to the passive radiator at the front of the speaker unit. Regarding a single dual voice coil speaker unit, the resonance angular frequency viewed from the first voice coil under the condition that the second voice coil is opened is ω ₀ ,
The equivalent mass is m ₀ , the compliance is C ₀ , the electrical sharpness is Q ₀ , the mechanical sharpness is Q _m , the ratio of the force coefficient of the second voice coil to the first voice coil is α, and the duplex using seen the number of the voice coil speaker units n, the compliance of C _b of the sealed air chamber of the speaker unit rear as viewed from the disposed a single speaker unit, an equivalent mechanical resistance r _b, likewise from a single speaker unit The compliance of the air chamber coupled to the passive radiator at the front of the speaker unit is C _f , the equivalent mechanical resistance is r _f , the equivalent mass of the passive radiator viewed from a single speaker unit is m _p , and the equivalent mechanical resistance is r _p ,
The equivalent mechanical compliance is C _p , the inductance of the impedance compensation circuit is L ₁ , L ₂ , and the capacitance is C ₁ , C ₂ , C
_{3. When} the resistors are r _C1 and r _{C 2} , and the resistances of the first and second voice coils are R _V1 and R _V2 , respectively, R _V2 and each element constant of the impedance compensation circuit are approximately

[0020]

(Equation 8)

[0021] A speaker system characterized by the following relationship:

[0022]

Embodiments of the present invention will be described below with reference to the drawings. Embodiment 1 FIG. FIG. 1 is a diagram showing a configuration of a speaker system according to an embodiment of the present invention. In FIG. 1, reference numeral 10 denotes an impedance compensation circuit for converting the electrical impedance of the speaker system to a constant resistance, 20-1,.
, 20-i, ..., 20-n are dual voice coil speaker units of the same specification, 21-1, ..., 21-i, ...,
21-n is the first voice coil, 22-1,..., 22-
i,..., 22-n are second voice coils, 25-1,.
, 25-i, ..., 25-n are bobbins for attaching voice coils, 50 is a passive radiator type cabinet, 52 is a passive radiator, and 100 is a signal input terminal to a speaker.

Here, a plurality of double voice coil speaker units are connected in parallel with the first voice coil being the first voice coil and the second voice coil being the second voice coil being the same in polarity. Have been. The impedance correction circuit 10 is connected in series to the second voice coil connected in parallel.

The passive radiator type cabinet means speaker units 20-1,..., 20-i,.
.., the cabinet 50 having a structure in which the rear space of the 20-n is acoustically coupled to the passive radiator 52 that emits sound to the outside.

Next, the operation will be described with reference to FIGS. Conventionally, the electrical impedance of a passive radiator type speaker system generally has a peak before and after an anti-resonance frequency as shown in FIG. This characteristic corresponds to the case where only the first voice coil of a plurality of units of the same specification connected in parallel is driven in the configuration of FIG. 1, and the speaker units 20-1,..., 20-i,.
..., the electric impedance due to 20-n as in the case of using a single unit, resulting in anti-resonance frequency f _r mountain near the case of driving a plurality of units. Therefore, 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 decrease in efficiency, the second voice coils 22-1,..., 22-i of a plurality of units connected in parallel with one impedance compensating circuit 10 for making the electrical impedance of the speaker system constant resistance. ···, Insert in series with 22-n.

Here, the value of the compensation circuit 10 is determined so that the electrical impedance of the speaker system becomes a constant resistance when a passive radiator type cabinet is used. That is, since the electrical impedance of only the first voice coil of a plurality of units connected in parallel is represented in FIG. 2, the selection is made so as to cancel the peak of the characteristic. This circuit is represented as shown in FIG. 3, and is expressed as follows in mathematical expression.

[0027]

(Equation 9)

Regarding the equation (1), the resistances r _C1 and r _C2 are jωL
Generally smaller than ₂ or 1 / (jωC ₂ ). Therefore, substantially the same effect can be obtained even if FIG. 3 is approximately replaced with the circuit of FIG. The circuit of FIG. 4 is as follows in mathematical expression.

[0029]

(Equation 10)

Here, each element constant of the impedance compensation circuit 10 depends on the number of double voice coil speaker units to be used and the dimensions of the passive radiator type cabinet, but the electric impedance of the speaker system is made completely constant resistance. Conditions are uniquely determined. When a passive radiator type cabinet is used, ω ₀ : resonance angular frequency of the dual voice coil speaker unit viewed from the first voice coil m ₀ : equivalent mass of the dual voice coil speaker unit viewed from the first voice coil C ₀ : Equivalent mechanical compliance of the double voice coil speaker unit viewed from the first voice coil Q ₀ : Electrical sharpness of the double voice coil speaker unit viewed from the first voice coil Q _m : First voice Mechanical sharpness of double voice coil speaker unit as viewed from coil α: ratio of force coefficient of second voice coil to first voice coil C _b : passive radiator method as viewed from a single unit provided compliance r _b volume by the air in the cabinet: viewed from disposed a single unit Passive radiator volume by equivalent mechanical resistance of type cabinet m _p: equivalent mass of the passive radiator as seen from the disposed a single unit r _p: provided by equivalent mechanical passive radiator as seen from a single unit Resistance C _p : Equivalent mechanical compliance of passive radiator viewed from a single unit provided R _V1 : Resistance of first voice coil R _V2 : Resistance of second voice coil n: Resistance of double voice coil speaker unit When the number is set, the resistance R _V2 of the second voice coil, the inductances L ₁ and L ₂ of the elements of the compensation circuit, the capacitances C ₁ , C ₂ and C ₃ ,
The resistances r _C1 and r _C2 are obtained from the following equations.

[0031]

[Equation 11]

FIG. 5 is a calculation result comparing the change of the sound pressure level characteristic and the change of the electric impedance characteristic depending on the presence or absence of the compensating element in the low sound range when two double voice coil speaker units of the same specification are used. As can be seen from FIG. 5, the impedance is constant resistance by compensating circuit, it can be seen that the sound pressure level at around the antiresonance frequency f _r is rising.

Embodiment 2 FIG. FIG. 6 is a diagram showing a configuration of a speaker system according to another embodiment of the present invention. 6, reference numeral 60 denotes a Kelton type cabinet provided with a passive radiator, and other reference numerals denote parts corresponding to those in FIG. 1, and a detailed description thereof will be omitted.

In FIG. 6, the Kelton type cabinet provided with a passive radiator means speaker units 20-1,..., 20-i,.
-n is a cabinet 60 having a structure in which the rear space is sealed and the space in front of the speaker unit is acoustically coupled to a passive radiator 52 that emits sound to the outside.

Next, the operation of the Kelton type speaker system provided with the conventional passive radiator will have peaks before and after the anti-resonance frequency as shown in FIG. 2, similarly to the passive radiator type. . This characteristic corresponds to the case where only the first voice coil of a plurality of units of the same specification connected in parallel is driven in the configuration of FIG.
0-1, ···, 20-i, ···, as with the electric impedance due to 20-n using a single unit, mountains around the antiresonance frequency f _r when driving the multiple units Is generated. Therefore, 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, a compensation circuit 10 for making the electrical impedance of the speaker system a constant resistance is inserted in series into the second voice coils of a plurality of units connected in parallel.

The determining herein as electrical impedance as a speaker system when the compensation circuit Z _C using Kelton type cabinet having a passive radiator becomes constant resistance. This circuit is generally represented in FIG. 3 as in the case of the passive radiator type cabinet, and its mathematical expression is the same as that of the expression (1).

Further, regarding the equation (1), the resistances r _C1 , r _C2
Is generally smaller than jωL ₂ or 1 / (jωC ₂ ),
Approximately the same effect can be obtained even when the circuit is approximately replaced with the circuit of FIG. Therefore, the mathematical expression is the same as the expression (2).

Here, the element constants of the impedance compensation circuit Z _C depend on the number of double voice coil speaker units to be used and the dimensions of the Kelton type cabinet provided with the passive radiator. The condition for making the resistance constant is uniquely determined. When a Kelton type cabinet equipped with a passive radiator is used, ω ₀ : resonance angular frequency of the double voice coil speaker unit viewed from the first voice coil m ₀ : double voice coil speaker viewed from the first voice coil Equivalent mass of the unit C ₀ : Equivalent mechanical compliance of the double voice coil speaker unit viewed from the first voice coil Q ₀ : Electrical sharpness Q _{m of the} double voice coil speaker unit viewed from the first voice coil Mechanical sharpness of the double voice coil speaker unit as viewed from the first voice coil α: ratio of the force coefficient of the second voice coil to the first voice coil C _b : viewed from the single speaker unit disposed equivalent of the speaker unit at the rear of the sealed air chamber mechanical compliance r _b: disposed Equivalent mechanical resistance of the closed air chamber at the rear of the speaker unit as viewed from the single speaker unit _Cf : Equivalent machine of the air chamber coupled to the passive radiator at the front of the speaker unit as viewed from the installed single speaker unit compliance r _f: provided by equivalent mechanical resistance of the air chamber that is coupled to passive radiator speaker unit front as viewed from a single speaker unit m _p: equivalent passive radiator as seen from the disposed a single unit Mass r _p : Equivalent mechanical resistance of passive radiator viewed from a single unit disposed C _p : Equivalent mechanical resistance compliance of passive radiator viewed from a single unit disposed R _V1 : First voice coil resistor R _V2: a double number of the voice coil unit: resistance n of the second voice coil , The resistance R _V2 of the second voice coil, the inductance L ₁ of the element of the compensation circuit, L _2, capacitor C _1, C _2, C _3,
The resistances r _C1 and r _C2 are obtained from the following equations.

[0039]

(Equation 12)

[0040]

As described above, according to the present invention, a passive radiator type or Kelton type cabinet provided with a passive radiator, and first and second voice coils, respectively, are provided with the same specifications attached to the cabinet. A plurality of dual voice coil speaker units, and a single impedance compensation circuit for converting the electrical impedance of the speaker system into a constant resistance, wherein the first voice coil has a polarity between the first voice coils. And the second voice coil is connected in parallel with the second voice coil having the same polarity.
An input signal is directly applied to each first voice coil, and an input signal via the impedance compensation circuit is applied to each second voice coil. The input to the system is always supplied constant, which can improve the sound radiation efficiency around the anti-resonance frequency of a speaker system with a passive radiator type or a Kelton type cabinet equipped with a passive radiator, and a plurality of units However, there is an effect that a system can be constructed at a low cost even if the above is used, and a sufficient volume required for bass reproduction can be secured.

Further, the impedance compensating circuit is configured such that the inductances of the circuit elements are L ₁ and L ₂ , the capacitance is C ₁ ,
When C ₂ , C ₃ , and resistances are r _C1 and r _C2 , the impedance Z _C of the impedance compensation circuit is represented by the above equation (1).

Further, the impedance compensating circuit is configured such that the inductances of the circuit elements are L ₁ and L ₂ , the capacitance is C ₁ ,
When C ₂ and C ₃ are used, since the impedance Z _C of the impedance compensating circuit is represented by the above equation (2),
Since the circuit is approximately replaced, the circuit can be simplified and the same effect can be obtained.

Further, the cabinet is a passive radiator type cabinet, and for a single dual voice coil speaker unit, the resonance angular frequency viewed from the first voice coil under the condition that the second voice coil is opened. ω ₀ , equivalent mass m ₀ , compliance C ₀ , electrical sharpness Q ₀ , mechanical sharpness Q _m , and the ratio of the force coefficient of the second voice coil to the first voice coil α. double the number of n of the voice coil speaker unit, a passive radiator system volume by the compliance of the air within the cabinet as viewed from the arranged has been one of the speaker units C _b, the mechanical resistance r _b, likewise one of the speaker units the equivalent mass of the passive radiator as seen from the m _p, the equivalent mechanical resistance r _p, the equivalent mechanical compliance C _p, in The inductance of the impedance compensation circuit is L ₁ , L ₂ , the capacitance is C ₁ , C ₂ , C ₃ , and the resistance is r _C1 , r _C2 ,
The resistances of the first and second voice coils are R _V1 and R _V2 , respectively.
In this case, R _V2 and the element constants of the impedance compensating circuit are approximately set in the relations represented by the above equations (3) to (15). Is obtained.

The cabinet is a Kelton type cabinet provided with a passive radiator, and has a sealed air chamber at the rear of the speaker unit and an air chamber connected to the passive radiator at the front of the speaker unit. Regarding the dual voice coil speaker unit, under the condition that the second voice coil is opened, the resonance angular frequency viewed from the first voice coil is ω ₀ , the equivalent mass is m ₀ , the compliance is C ₀ , and the electrical sharpness is Q ₀ , the mechanical sharpness Q _m , the ratio of the force coefficient of the second voice coil to the first voice coil α, the number of double voice coil speaker units used n, the single speaker arranged the speaker unit rear of sealed air chamber of compliance as seen from unit C _b, the equivalent mechanical resistance r _b, similarly The compliance of the air chamber coupled to the passive radiator at the front of the speaker unit viewed from a single speaker unit is C _f , the equivalent mechanical resistance is r _f ,
Similarly, the equivalent mass of the passive radiator viewed from a single speaker unit is m _p , the equivalent mechanical resistance is r _p , the equivalent mechanical compliance is C _p , the inductance of the impedance compensation circuit is L ₁ , L ₂ , and the capacitance is C ₁ , C _2, C _3, the resistance r _C1, r _C2, first, when the resistance of the second voice coil respectively, and R _V1, R _V2, the element constants of R _V2 and impedance compensation circuit schematic above (16) (30), the above effects can be obtained in a speaker system including a Kelton type cabinet provided with a passive radiator.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a speaker system according to an embodiment of the present invention.

FIG. 2 is a diagram showing a comparison of electric impedance characteristics of a passive radiator type speaker system depending on the presence or absence of a compensation circuit.

FIG. 3 is a diagram showing an example of a circuit configuration of an impedance compensation circuit according to the present invention.

FIG. 4 is a diagram showing another example of the circuit configuration of the impedance compensation circuit according to the present invention.

FIG. 5 is a diagram comparing changes in sound pressure characteristics and electric impedance characteristics depending on the presence or absence of a compensation element in a low sound range.

FIG. 6 is a diagram showing a configuration of a speaker system according to another embodiment of the present invention.

FIG. 7 is a diagram showing a speaker configuration using a conventional dual voice coil.

FIG. 8 is a diagram showing a comparison of the electric impedance characteristics of a speaker using a conventional dual voice coil with and without a compensation circuit.

FIG. 9 is a diagram showing a comparison of sound pressure characteristics of a speaker using a conventional dual voice coil with and without a compensation circuit.

FIG. 10 is a diagram showing a configuration of a conventional speaker system using a plurality of dual voice coil speaker units.

[Explanation of symbols]

10 Impedance compensation circuit, 20-1 to 20-n dual voice coil speaker unit, 21-1 to 21-n
1st voice coil, 22-1 to 22-n 2nd voice coil, 25-1 to 25-n bobbin, 50 passive radiator type cabinet, 52 passive radiator, 60 Kelton type cabinet provided with passive radiator, 100 signals Input terminal.

Claims (5)

[Claims] 1. A plurality of dual voice coil speakers having a passive radiator type or a Kelton type cabinet provided with a passive radiator, and first and second voice coils, respectively, and having the same specification and mounted on the cabinet. And a single impedance compensating circuit for converting the electrical impedance of the speaker system into a constant resistance. The first voice coil is connected in parallel with the first voice coil with the same polarity, and the second voice coil is connected in parallel with the second voice coil. Are connected in parallel with the second voice coils having the same polarity, and an input signal is directly applied to each first voice coil, and an input signal is applied to each second voice coil through the impedance compensation circuit. A speaker system, characterized in that a voltage is applied to the speaker system. 2. The impedance of the circuit element of the impedance compensation circuit is L ₁ , L ₂ , and the capacitance is C ₁ , C ₂ , C ₃ ,
The speaker system according to claim 1, wherein when the resistances are r _C1 and r _C2 , the impedance Z _C of the impedance compensation circuit is represented by the following equation. (Equation 1) 3. When the inductances of the circuit elements of the impedance compensation circuit are L ₁ and L ₂ and the capacitances are C ₁ , C ₂ and C ₃ , the impedance Z _{C of the} impedance compensation circuit is set.
Is a circuit represented by the following equation:
The speaker system described in 1. (Equation 2) 4. The cabinet according to claim 1, wherein the cabinet is a passive radiator type cabinet, and for a single dual voice coil speaker unit, the resonance angular frequency viewed from the first voice coil is determined under the condition that the second voice coil is opened. ω ₀ , equivalent mass m ₀ , compliance C ₀ , electrical sharpness Q ₀ , mechanical sharpness Q _m , and the ratio of the force coefficient of the second voice coil to the first voice coil α. double the number of n of the voice coil speaker unit, a passive radiator system volume by the compliance of the air within the cabinet as viewed from the arranged has been one of the speaker units C _b, the mechanical resistance r _b, likewise one of the speaker units the equivalent mass of the passive radiator as seen from the m _p, the equivalent mechanical resistance r _p, the equivalent mechanical compliance C _p, Inpi L ₁ the inductance of the Nsu compensation circuit,
L ₂ , capacitance C ₁ , C ₂ , C ₃ , resistance r _C1 , r _C2 , first,
_{4. The} device according to claim 2, wherein when the resistance of the second voice coil is R _V1 and R _V2 , respectively, R _V2 and each element constant of the impedance compensating circuit have a relationship approximately represented by the following equation. 5. Speaker system. (Equation 3) 5. The cabinet according to claim 1, wherein the cabinet is a Kelton type cabinet provided with a passive radiator, wherein the cabinet has a sealed air chamber at the rear of the speaker unit and an air chamber coupled to the passive radiator at the front of the speaker unit. Regarding the dual voice coil speaker unit, under the condition that the second voice coil is opened, the resonance angular frequency viewed from the first voice coil is ω ₀ , the equivalent mass is m ₀ ,
Compliance is C ₀ , electrical sharpness is Q ₀ , mechanical sharpness is Q _m , the ratio of the force coefficient of the second voice coil to the first voice coil is α, and the number of double voice coil speaker units used N, the compliance of the closed air chamber at the rear of the speaker unit as viewed from the disposed single speaker unit is C _b , the equivalent mechanical resistance is r _b , similarly at the front of the speaker unit as viewed from the single speaker unit. The compliance of the air chamber coupled to the passive radiator is C _f , the equivalent mechanical resistance is r _f , similarly, the equivalent mass of the passive radiator viewed from a single speaker unit is m _p , the equivalent mechanical resistance is r _p , and the equivalent mechanical compliance is C _p, L ₁ the inductance of the impedance compensation circuit, L _2, C ₁ to capacitance, C _2, C _3, the resistance r _C1, r _{C 2} First, when the second respectively the resistance of the voice coil R _V1, R _V2, claim 2 or 3 each element constants of R _V2 and impedance compensation circuit is characterized in that it is in the relationship shown schematically under formula The speaker system described in 1. (Equation 4)