JP3335828B2 - Horn speaker system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention eliminates air distortion caused by overload of air in a horn or a compression driver, regardless of fluctuations in the amplification factor of a power amplifier provided in a preceding stage of a horn speaker. The present invention relates to a horn speaker system that realizes high-fidelity reproduction for a signal.

[0002]

2. Description of the Related Art In a conventional horn loudspeaker system, second-order harmonic distortion and cross-modulation distortion have occurred due to an overload of air in a horn or a compression driver.

[0003]

In order to further reduce such second-order harmonic distortion and cross-modulation distortion, the applicant has filed a horn speaker system as follows (not disclosed). First, the horn speaker system will be described below.

FIG. 5 is a block diagram modeling a horn speaker system of the prior application. In this figure, the horn speaker system includes a distortion removing device 90 and a distortion removing device 9.
It is composed of a power amplifier 91 for amplifying an output of 0 and a horn speaker 92 for converting the output to a sound.

Here, the horn speaker 92 includes a system 98 of a transfer function H1 of a horn speaker without distortion, a system 99 of a transfer function H2 representing a second-order distortion of the horn speaker, and a system 9 of a transfer function H2.
8 and an adder 100 that adds each output of the system 99 are equivalently represented. The power amplifier 91 is an amplifier that multiplies the output signal of the distortion removing device 90 by A and supplies the output signal to the horn speaker 92. The distortion removal device 90 includes an A / D converter 93 that converts an input signal x (t), which is an analog acoustic signal, into a digital signal, a first filter 94 that performs a one-dimensional convolution operation using a transfer function G1, and a transfer function. A second filter 95 for performing a two-dimensional convolution operation with the function G2, and a first filter 9
4 and an output signal of the second filter 95, and a D / A converter 97 for converting the output signal of the adder 96 into an analog signal.

In such a horn speaker system,
The relationship between the input signal x (t) and the output signal y (t) can be expressed by the following equation (5) when a signal on the time axis is converted into a signal on the frequency axis.

(Equation 7) The first term of the equation (5) indicates a component of x (t) passing through the first filter 94 and the system 98 of the transfer function H1 of the horn speaker. The first term in parentheses in the second term of the equation (5) is x
(T) shows a component passing through the second filter 95 and the system 98 of the transfer function H1 of the horn speaker. The second term in parentheses of the second term of the equation (5) is that x (t) is the first filter 9
System 99 of transfer function H2 representing distortion of horn 4 and horn speaker
And the components passing through.

However, m in the second term of equation (5) is m = m1 +
This is the sum of all combinations that satisfy m2 or | m1-m2 |. Note that x (t) is the second filter 95
Of the transfer function H2 representing the distortion of the horn speaker
The components passing through are small compared to the other terms and are ignored.

In order to remove the distortion component of the horn speaker 92, the two terms in the parentheses of the second term of the equation (5) need only be canceled and their values become zero. Therefore, the transfer function G1 of the first filter 94 and the transfer function G2 of the second filter 95 are determined so that the following equations (6) and (7) are satisfied.

(Equation 8)

(Equation 9)

However, in the above horn speaker system, when the amplification factor A of the power amplifier 91 is changed after the transfer function G2 of the second filter 95 is determined by the equation (7), the distortion removal as originally intended is performed. There is a problem that the effect cannot be obtained. In the horn speaker 92, when the input signal is A times, the secondary distortion component included in the output signal is A ² times. In order to remove the distortion component multiplied by A ² , the filter tap of the second filter 95 must be multiplied by A. This was difficult with the horn speaker system described above.

According to the equation (5), when the amplification factor A of the power amplifier changes after determining the characteristic G1 of the first filter and the characteristic G2 of the second filter, the second term of the equation (5) The two terms in parentheses do not cancel. That is, this means that the output signal y (t) contains a distortion component.

The present invention has been made in view of such a conventional problem. Even when the amplification factor A of a power amplifier provided in front of a horn speaker is changed, a desired distortion removal effect can be obtained. The purpose of the present invention is to realize a horn speaker system that can obtain the following.

[0012]

According to the first and third aspects of the present invention, there is provided a distortion removing apparatus comprising:
Filter creates a signal component for removing a distortion component of the horn speaker. A multiplication coefficient α1 corresponding to the amplification factor A of the power amplifier is set in a multiplier that multiplies the output of the filter by a multiplication coefficient. In this way, regardless of the amplification factor A of the power amplifier, distortion generated due to overload of the air in the horn of the horn speaker or in the compression driver is removed, and the audio signal input to the horn speaker system can be reproduced with high fidelity. Will be played.

Further, according to the second and fourth aspects of the present invention, the multiplier of the distortion eliminator converts the output signal of the A / D converter into
Multiplication is performed with the multiplication coefficient α2. And the second filter is
A two-dimensional convolution operation is performed on the output signal of the multiplier. In this way, a signal component for removing the distortion component of the horn speaker from the second filter is created. Thus, regardless of the amplification factor A of the power amplifier, distortion generated due to overload of air in the horn of the horn speaker or in the compression driver is removed, and the audio signal input to the horn speaker system becomes high. Played faithfully.

Further, according to the third and fourth aspects of the present invention, the distortion removal device is provided with amplification factor detection means for the power amplifier and multiplication coefficient control means for the multiplier, so that the amplification factor of the power amplifier is changed on the way. Even so, the multiplier coefficient of the multiplier optimally tracks, and the audio signal input to the horn speaker system is reproduced with high fidelity.

[0015]

The invention according to claim 1 is a horn speaker system in which a power amplifier is connected to a signal input section of a horn speaker and a distortion removing device is connected to an input section of the power amplifier. An A / D converter for converting an analog audio signal into a digital signal, a first filter for performing a one-dimensional convolution operation on an output signal of the A / D converter, and the A / D converter A second filter for performing a two-dimensional convolution operation on the output signal of the second filter, a multiplier for multiplying the output signal of the second filter by a predetermined coefficient, an output signal of the first filter and the multiplier And an D / A converter that converts a digital output signal of the adder into an analog signal and outputs the analog signal to the power amplifier.

With such a configuration, the A / D converter in the distortion removing apparatus receives an analog sound signal,
Convert audio signals to digital signals. The first filter performs a one-dimensional convolution operation on the output signal of the A / D converter, and the second filter performs a two-dimensional convolution operation. The multiplier multiplies the output signal of the second filter by the multiplication coefficient α1. The adder adds the first filter and the output signal of the multiplier. The D / A converter converts the output signal of the adder into an analog signal and outputs the analog signal to a power amplifier.
The power amplifier amplifies the input signal by A times and supplies it to the horn speaker. At this time, the signal component for removing the distortion component of the horn speaker is created by the second filter, and the multiplier sets the multiplication coefficient α1 corresponding to the amplification factor A of the power amplifier. Regardless, the distortion caused by the overload of the air in the horn and the compression driver is removed.

According to a second aspect of the present invention, there is provided a horn speaker system in which a power amplifier is connected to a signal input section of a horn speaker and a distortion removing apparatus is connected to an input section of the power amplifier. An A / D converter for converting an analog audio signal into a digital signal, a first filter for performing a one-dimensional convolution operation on the output signal of the A / D converter, and an output signal of the A / D converter. A multiplier that multiplies by a predetermined coefficient, a second filter that receives an output signal of the multiplier and performs a two-dimensional convolution operation,
An adder for adding the output signal of the first filter and the output signal of the second filter, and a D / A converter for converting a digital output signal of the adder into an analog signal and outputting the analog signal to the power amplifier And characterized in that:

With this configuration, when an analog sound signal is input, the A / D converter in the distortion removing device converts the sound signal into a digital signal. The first filter performs a one-dimensional convolution operation on the output signal of the A / D converter. The multiplier multiplies the output signal of the A / D converter by a multiplication coefficient α2. The second filter performs a two-dimensional convolution operation on the output signal of the multiplier. The adder adds the output signals of the first filter and the second filter. The D / A converter converts the output signal of the adder into an analog signal. The power amplifier converts the output signal of the D / A converter to A
After doubling the power, it is given to a horn speaker. At this time, a signal component for removing the distortion component of the horn speaker is created by the second filter, and the multiplier sets the multiplication coefficient α2 corresponding to the amplification factor A of the power amplifier. Regardless, the distortion caused by the overload of the air in the horn and the compression driver is removed.

According to a third aspect of the present invention, there is provided a horn speaker system in which a power amplifier is connected to a signal input portion of a horn speaker, and a distortion removing device is connected to a signal input portion of the power amplifier. An A / D converter for converting an analog sound signal into a digital signal;
A first filter that performs a one-dimensional convolution operation on the output signal of the D converter, a second filter that performs a two-dimensional convolution operation on the output signal of the A / D converter, and the second filter. A multiplier for multiplying the output signal of the filter by a predetermined coefficient, an adder for adding the output signal of the first filter and the output signal of the multiplier, and a digital output signal of the adder to an analog signal A D / A converter that converts and outputs the converted power to the power amplifier, an amplification factor detection unit that detects an amplification factor of the power amplifier, and a multiplication of the multiplier based on the amplification factor detected by the amplification factor detection unit. And a multiplication coefficient controller for controlling a coefficient.

With such a configuration, the amplification factor detection means detects the amplification factor of the power amplifier and supplies the value to the multiplication coefficient control means. This allows the multiplier to control the multiplication factor,
Follows changes in the power amplifier gain. In this case, even if the amplification factor A of the power amplifier changes on the way, the distortion generated due to the overload of the air in the horn or the compression driver is automatically removed.

According to a fourth aspect of the present invention, there is provided a horn speaker system in which a power amplifier is connected to a signal input section of a horn speaker and a distortion removing apparatus is connected to a signal input section of the power amplifier. An A / D converter for converting an analog sound signal into a digital signal;
A first filter that performs a one-dimensional convolution operation on the output signal of the D converter, a multiplier that multiplies the output signal of the A / D converter by a predetermined coefficient, A second filter for performing a two-dimensional convolution operation by
An adder for adding the output signal of the first filter and the output signal of the second filter, and a D / A converter for converting a digital output signal of the adder into an analog signal and outputting the analog signal to the power amplifier And an amplification factor detecting means for detecting an amplification factor of the power amplifier; and a multiplication factor controller for controlling a multiplication factor of the multiplier based on the amplification factor detected by the amplification factor detection device. It is characterized by the following.

In such a configuration, the connection position of the multiplier is provided before the second filter, and the same operation as in the third aspect of the invention is achieved.

According to a fifth aspect of the present invention, in the electro-acoustic conversion characteristics of the horn speaker, the transfer function of the horn speaker without distortion is represented by H1, the transfer function representing the second-order distortion is represented by H2, and the transmission of the horn speaker is performed. Function H1
And H2 in parallel, the amplification factor of the power amplifier is A, and in the distortion removing device,
The transfer function of the second filter is G1, the transfer function of the second filter is G2, and the transfer functions H1 and G1 are expressed by using the frequency m as a parameter.
(M) and G1 (m), and the transfer functions H2 and G2 are frequency m (where m = mi + mj or m = | mi-m
j |) as parameters as H2 (m1, m2) and G2 (m1, m2), respectively.
And the multiplication coefficient of the multiplier is α1, (1)
Equations (1), (2), and (3) are simultaneously satisfied so that
It is characterized in that the characteristics of the second filter and the multiplication coefficient α1 are set.

According to such a configuration, claim 1 or 3
In the described invention, the transfer function of the horn speaker is H1
When the amplification factor of the power amplifier is A and the transfer functions of the first and second filters of the distortion removal device are G1 and G2, respectively,
The transfer function G is set so that the equations (2) and (3) are simultaneously satisfied.
If the values of 1, G2 and the multiplication coefficient α1 are determined, the distortion removing device can be designed more specifically.

According to a sixth aspect of the present invention, in the horn loudspeaker system, the transfer function of the horn loudspeaker without distortion is H1, and the transfer function representing the second-order distortion is H2.
And the transfer function of the horn speaker is represented as a parallel connection of H1 and H2, and the amplification factor of the power amplifier is A
In the distortion removing apparatus, the transfer function of the first filter is G1, the transfer function of the second filter is G2, and the transfer functions H1 and G1 are expressed by using the frequency m as a parameter as H1. (M), G1
(M), and the transfer functions H2 and G2 expressed as parameters of the frequency m (however, m = mi + mj or a combination of m = | mi-mj |) are represented as H2 (m1, m2) and G2, respectively. (M1, m2), and the multiplication coefficient of the multiplier is α2, Equation (1), (2)
And (4) are simultaneously established.

According to such a configuration, claim 2 or claim 4
In the described invention, the transfer function of the horn speaker is H1
When the amplification factor of the power amplifier is A and the transfer functions of the first and second filters of the distortion removal device are G1 and G2, respectively,
The transfer function G is set so as to simultaneously satisfy the equations (2) and (4).
If the values of 1, G2 and the multiplication coefficient α2 are determined, the distortion removing device can be designed more specifically.

Embodiment 1 A horn speaker system according to a first embodiment of the present invention will be described with reference to FIG. 1 and mathematical expressions. FIG. 1 is a block diagram schematically showing the configuration of the horn speaker system of the first embodiment. As shown in the figure, the horn speaker system includes a distortion removing device 10, a power amplifier 11, and a horn speaker 12.

When the input signal x (t) is input, the distortion removing device 10 performs a one-dimensional convolution operation and a two-dimensional convolution operation on x (t), and adds the operation results. Output. A / D
Converter 13, first filter 14, second filter 1
5, an adder 16, a D / A converter 17, and a multiplier 18.

When the input signal x (t), which is an electroacoustic signal, is input to the distortion removing device 10, the A / D converter 13
A circuit for performing A / D conversion. The first filter 14 has a transfer function G1 and performs a one-dimensional convolution operation on the output signal of the A / D converter 13. The second filter 15 has a transfer function G2 and the A / D converter 13
Is a filter that performs a two-dimensional convolution operation on the output signal of. The multiplier 18 is a circuit that multiplies the output signal of the second filter 15 by a multiplication coefficient α1. The adder 17 is a circuit that adds the output signals of the first filter 14 and the multiplier 18. The D / A converter 17 performs D / A conversion on the output signal of the adder 16 and outputs the output signal z.
This is a circuit for applying (t) to the power amplifier 11.

The power amplifier 11 is a circuit that performs power amplification on the output signal z (t) of the distortion removing device 10 at an amplification factor A and supplies the output signal A · z (t) to the horn speaker 12. The horn speaker 12 is an electroacoustic transducer that outputs an output signal y (t) as a sound to a space when the amplified sound signal A · z (t) is input. The horn speaker 12 includes a system 19 of a first-order transfer function H1 (m) having no distortion in the input / output characteristics as described above, and a second-order transfer function H2 representing the second-order distortion in the input / output characteristics.
It can be equivalently expressed as the sum of the output signal of the system 20 of (m1, m2) and the adder 21.

First, the details of the input / output characteristics of the horn speaker 12 will be described with reference to mathematical expressions. When the input signal A · z (t) is input to the horn speaker 12, the output signal y (t) is expressed as in Expression (8).

(Equation 10) Here, Z (m) is obtained by performing digital Fourier transform to convert z (t) in the time axis into a frequency axis, and Y (m) performs digital Fourier transform on y (t). It is represented. H1 (m) is a transfer function of a system 19 representing a linear input / output characteristic of the horn speaker 12, and H2 (m1, m2) is a transfer function of a system 20 representing a second-order nonlinear distortion generated in the horn. is there.
Note that the second term of this equation is m = m1 + m2 or m = m1 + m2.
| M1-m2 | is the sum of all combinations that satisfy | m1-m2 |. That is, m1 and m2 are values obtained by decomposing the frequency m into a sum of arbitrary frequencies or a frequency difference.

The first term of the equation (8) is a signal Z having a frequency m.
FIG. 6 shows a linear output signal component of the horn speaker 12 with respect to (m). The second term in equation (8) is the input signal Z (m
1) shows a nonlinear output signal component of the horn speaker 12 with respect to Z (m2), and the second term represents a second-order distortion component generated due to an overload of air in the horn or the compression driver. An object of the present invention is to remove the distortion of the output signal of the horn speaker 12 according to the second term of the equation (8) even when the amplification factor A of the power amplifier 11 fluctuates.

Next, the input signal x (t) of the distortion removing device 10
And the output signal z (t) is shown in equation (9).

[Equation 11] In the equation (9), X (m) is a value obtained by discretizing the input signal x (t) and expressing it by digital Fourier transform.
(M) represents the output signal z (t) discretized and represented by digital Fourier transform. The first term of the expression (9) is a component of the output signal z (t) that has passed through the first filter 14, and the second term of the expression (9) is the second component of the output signal z (t). Are components that have passed through the filter 15 and the multiplier 18. The addition symbol in the expression (9) indicates the operation of the adder 16. Also, the second term of this equation is m = m1 + m2, or
m = | m1−m2 | is the sum of all combinations that satisfy | m1 | m2 |.

Next, the transfer function G1 of the first filter 14
And the transfer function G2 of the second filter 15 will be described using mathematical expressions. As described above, the input / output relationship of the distortion removing device 10 is expressed by the expression (9), and the horn speaker 12
Is expressed by equation (8), substituting Z (m) in equation (9) for Z (m) in equation (8) gives (10)
An expression is obtained.

(Equation 12)

In the expression (10), the first term of the right side of the output signal Y (m) is that the input signal X (m) passes through the first filter 14 of the distortion removing device 10 and the horn speaker 1
This is a component that has passed through the system 19 having a transfer function H1 of 2.
The second term of equation (10) is the input signals X (m1), X (m2)
Is the second filter 15 and the multiplier 1 of the distortion removal device 10.
8, which passes through the system 19 having the transfer function H1 of the horn speaker 12. The third term of the equation (10) is that the input signals X (m1) and X (m2) are the first
Is a component that has passed through the filter 14 and passed through the system 20 having the transfer function H2 of the horn speaker 12. The fourth term of the equation (10) is that at least one of the input signals X (m1) and X (m2) passes through the second filter 15 of the distortion removing device 10, and
And a system 20 having a transfer function H2 of the horn speaker 12.
It is a component that has passed.

The second and third terms of the equation (10) are m = m1
+ M2 or the sum of all combinations that satisfy m = | m1-m2 |, and the fourth term is m1 = m3 + m4
Or | m3-m4 |, m2 = m5 + m6 or | m5-m
6 | is the sum for all combinations that satisfy 6 |. Here, the fourth term of the expression (10) is a minute signal and is ignored, and the expression (10) is rearranged into the expression (11).

(Equation 13) In the equation (11), the second term is m = m1 + m2, or
m = | m1−m2 | is the sum of all combinations that satisfy | m1 | m2 |.

In order for the horn speaker system to realize high-fidelity reproduction, the output signal Y (m) is converted from the input signal X (m) to the power of the amplification factor A as desired characteristics, for example, as shown in equation (12). It suffices if it is equal to AX (m) amplified by the amplifier. In order to realize this, it is only necessary that the right side of the equation (11) is equal to the right side of the equation (12). Therefore,
When all of the expressions (1), (2) and (3) hold,
Equation (12) is satisfied.

[Equation 14]

(Equation 15)

(Equation 16)

[Equation 17]

Here, when the amplification factor A of the power amplifier 11 fluctuates, only the expression (3) has a relation with the amplification factor A in the expressions (1), (2) and (3). . Therefore, even when the amplification factor A fluctuates, it is not necessary to change the taps of the first and second filters, and the distortion of the horn speaker is removed only by changing the value of the multiplication coefficient α1 of the multiplier 18 to A. can do.

By performing such signal processing, distortion of the sound pressure signal due to air overload in the horn of the horn speaker or the compression driver is removed without being affected by the amplification factor of the power amplifier 11. be able to. For this reason, the input / output signals of the horn speaker system are greatly improved, and high-fidelity reproduction is possible.

(Embodiment 2) A horn speaker system according to a second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a block diagram schematically showing the configuration of the horn speaker system according to the second embodiment. As shown in the figure, the horn speaker system includes a distortion removing device 30, a power amplifier 31, and a horn speaker 32. The distortion removing device 30 includes an A / D converter 33, a first filter 34, a second filter 35, an adder 36, a D / A converter 37, and a multiplier 38. Also regarding the horn speaker 32, a system 39 of a transfer function H1 of a horn speaker without distortion, a system 40 of a transfer function H2 representing a secondary distortion of the horn speaker, and an adder for adding each output of the system 39 and the system 40. 41 and equivalently. Detailed descriptions of the functional description and signals of the blocks having the same names as in the first embodiment will be omitted.

The present embodiment differs from the first embodiment in that the multiplier 38 is not provided after the second filter 35 but is provided before the second filter 35. The multiplier 38 multiplies the output signal of the A / D converter 33 by a multiplication coefficient α2 and supplies the output signal to the second filter 35. However, the first filter 34 has an A / D filter as in the first embodiment.
The output signal of the converter 33 is input.

In the present embodiment, the relationship between the input signal X (m) and the output signal Z (m) of the distortion removing device 20 is expressed by equation (13).

(Equation 18) In the equation (13), α2 is a multiplication coefficient of the multiplier 38. Further, the input / output characteristics of the horn speaker 32 are expressed as in equation (8), as in the first embodiment.

Here, similarly to the first embodiment,
Substituting Z (m) in equation (13) for Z (m) in equation (8),
When the small signal term is ignored, the equation (14) is obtained.

[Equation 19]

In order for the horn speaker system to realize high-fidelity reproduction, the output signal Y (m) is converted from the input signal X (m) to the power of the amplification factor A as desired characteristics, for example, as shown in equation (12). It suffices if it is equal to AX (m) amplified by the amplifier. In order to realize this, it is only necessary that the right side of the equation (12) is equal to the right side of the equation (14). Therefore, when all of the above-mentioned expressions (1), (2), and the following expression (4) are satisfied, the above-mentioned expression (12) is satisfied.

(Equation 20)

Here, when the amplification factor A of the power amplifier 31 fluctuates, in the expressions (1), (2) and (4), the relationship with the amplification factor A is shown above (4). ) Expression only. Therefore, even when the amplification factor A fluctuates, it is not necessary to change the taps of the first and second filters to remove distortion of the horn speaker, and only the multiplication coefficient α2 of the multiplier 38 needs to be changed. .

By performing such signal processing, distortion of the sound pressure signal due to air overload in the horn of the horn speaker or the compression driver can be removed without being affected by the amplification factor of the power amplifier. Can be. For this reason, the input / output signals of the horn speaker system are greatly improved, and high-fidelity reproduction becomes possible.

(Third Embodiment) A horn speaker system according to a third embodiment of the present invention will be described with reference to FIG. FIG. 3 is a block diagram schematically showing the configuration of the horn speaker system according to the third embodiment. As shown in the figure, the horn speaker system includes a distortion removing device 50, a power amplifier 51, and a horn speaker 52.
It is comprised including.

The distortion removing device 50 includes an A / D converter 53,
First filter 54, second filter 55, adder 5
6, D / A converter 57, multiplier 58, amplification factor detecting means 5
9, constituted by a multiplication coefficient control means 60. Also for the horn speaker 52, a system 61 of a transfer function H1 of a horn speaker without distortion, a system 62 of a transfer function H2 representing a secondary distortion of the horn speaker, and an adder for adding each output of the system 61 and the system 62. 63 and equivalently. The description of the function and the signal of the block having the same name as in the first embodiment will be omitted.

The present embodiment differs from the first embodiment in that the distortion removing device 50 is provided with an amplification factor detecting means 59 and a multiplication coefficient controlling means 60. The multiplier coefficient of the multiplier 58 is α3 equal to α1. In this embodiment, in order for the horn speaker system to realize high-fidelity reproduction, the right side of Expression (11) and the right side of Expression (12) need to be equal to each other as in the first embodiment. Therefore,
It suffices that all of the expressions (1), (2) and (3) hold.

The amplification factor detection means 59 is a means for detecting the amplification factor A of the power amplifier 31. Multiplication coefficient control means 60
Is based on the amplification factor A given from the amplification factor detection means 59,
The multiplication coefficient is determined by the operation of the equation (3), and the multiplier 58
Is a means for controlling the operation coefficient α3.

By configuring the horn speaker system in this manner, even when the amplification factor A of the power amplifier 51 is not known in advance, or when it is desired to change the amplification factor A during the reproduction of the music signal, the music signal can be reproduced with high fidelity. It can be carried out.

(Embodiment 4) A horn speaker system according to a fourth embodiment of the present invention will be described with reference to FIG. FIG. 4 is a block diagram schematically showing the configuration of the horn speaker system according to the fourth embodiment. As shown in the figure, the horn speaker system includes a distortion removing device 70, a power amplifier 71, and a horn speaker 72.
It is comprised including.

The distortion removing device 70 includes an A / D converter 73,
First filter 74, second filter 75, adder 7
6, D / A converter 77, multiplier 78, amplification detection means 7
9. Multiplication coefficient control means 80. Also regarding the horn speaker 72, a system 81 of the transfer function H1 of the horn speaker without distortion, a system 82 of the transfer function H2 representing the secondary distortion of the horn speaker, and an adder for adding each output of the system 81 and the system 82. 83 and equivalently. The description of the function and the signal of the block having the same name as the fourth embodiment will be omitted.

The present embodiment is different from the third embodiment in that a multiplier 78 for a multiplication coefficient α4 is provided in a stage preceding the second filter 75 in the distortion removing device 70.
It is assumed that the multiplier coefficient α4 of the multiplier 78 is equal to α2.

In the horn speaker system having such a configuration, in order to realize high-fidelity reproduction, the right side of the expression (12) and the right side of the expression (14) need to be equal to each other, as in the second embodiment. Therefore, all of the expressions (1), (2), and (4) should be satisfied. The amplification factor detection means 79 detects the amplification factor A of the power amplifier 71 and outputs it to the multiplication coefficient control means 80. The multiplication coefficient control means 80 determines the multiplication coefficient α2 by the operation of the equation (4) based on the amplification factor A, and supplies it to the multiplier 406.

Thus, the amplification factor A of the power amplifier 71
Is not known in advance, or the amplification factor A is
The horn speaker system can perform high-fidelity reproduction of a music signal even when it is desired to change the audio signal.

[0057]

As described above, according to the present invention, a horn speaker that reproduces an input signal with high fidelity irrespective of the amplification factor of a power amplifier by providing a multiplier at a stage after or at a stage before the second filter. The system can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a horn speaker system according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a horn speaker system according to a second embodiment of the present invention.

FIG. 3 is a block diagram illustrating a configuration of a horn speaker system according to a third embodiment of the present invention.

FIG. 4 is a block diagram illustrating a configuration of a horn speaker system according to a fourth embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a horn speaker system of the prior application.

[Explanation of symbols]

10, 30, 50, 70, 90 Distortion remover 11, 31, 51, 71, 91 Power amplifier 12, 32, 52, 72, 92 Horn speaker 13, 33, 53, 73, 93 A / D converter 14, 34, 54, 74, 94 First filter 15, 35, 55, 75, 95 Second filter 16, 21, 36, 41, 56, 63, 76, 83, 9
6,100 Adders 17,37,57,77,97 D / A converters 18,38,58,78 Multipliers 19,39,61,81,98 One-dimensional transfer function H1
20, 40, 62, 82, 99 Two-dimensional transfer function H2
59, 79 Gain detection means 60, 80 Multiplication coefficient control means

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04R 3/00 310 H04R 1/30

Claims (6)

(57) [Claims] 1. A horn speaker system in which a power amplifier is connected to a signal input unit of a horn speaker and a distortion removing device is connected to an input unit of the power amplifier, wherein the distortion removing device converts an analog sound signal into a digital signal. An A / D converter for conversion; a first filter for performing a one-dimensional convolution operation on an output signal of the A / D converter; and a two-dimensional convolution on an output signal of the A / D converter A second filter that performs an operation, a multiplier that multiplies an output signal of the second filter by a predetermined coefficient, and an adder that adds an output signal of the first filter and an output signal of the multiplier. And a D / A converter that converts a digital output signal of the adder into an analog signal and outputs the analog signal to the power amplifier. 2. A horn speaker system in which a power amplifier is connected to a signal input portion of a horn speaker and a distortion removing device is connected to an input portion of the power amplifier, wherein the distortion removing device converts an analog audio signal into a digital signal. An A / D converter for conversion; a first filter for performing a one-dimensional convolution operation on an output signal of the A / D converter; and a multiplication of the output signal of the A / D converter by a predetermined coefficient. A multiplier, a second filter that receives the output signal of the multiplier and performs a two-dimensional convolution operation, and an adder that adds the output signal of the first filter and the output signal of the second filter And a D / A converter that converts a digital output signal of the adder into an analog signal and outputs the analog signal to the power amplifier. . 3. A horn speaker system in which a power amplifier is connected to a signal input unit of a horn speaker and a distortion removing device is connected to a signal input unit of the power amplifier, wherein the distortion removing device converts an analog sound signal. An A / D converter for performing digital conversion, a first filter for performing a one-dimensional convolution operation on an output signal of the A / D converter, and a two-dimensional filter for an output signal of the A / D converter. A second filter that performs a convolution operation, a multiplier that multiplies an output signal of the second filter by a predetermined coefficient, and an adder that adds an output signal of the first filter and an output signal of the multiplier A D / A converter that converts a digital output signal of the adder into an analog signal and outputs the analog signal to the power amplifier; an amplification factor detection unit that detects an amplification factor of the power amplifier; A horn speaker system, comprising: a multiplication coefficient controller that controls a multiplication coefficient of the multiplier based on an amplification factor detected by an amplification factor detection unit. 4. A horn speaker system in which a power amplifier is connected to a signal input unit of a horn speaker and a distortion removing device is connected to a signal input unit of the power amplifier, wherein the distortion removing device converts an analog sound signal. An A / D converter for performing digital conversion; a first filter for performing a one-dimensional convolution operation on the output signal of the A / D converter; and a multiplication of the output signal of the A / D converter by a predetermined coefficient A second filter that performs a two-dimensional convolution operation on the output signal of the multiplier; and an adder that adds the output signal of the first filter and the output signal of the second filter. A D / A converter that converts a digital output signal of the adder into an analog signal and outputs the analog signal to the power amplifier; an amplification factor detection unit that detects an amplification factor of the power amplifier; A horn speaker system, comprising: a multiplication coefficient controller that controls a multiplication coefficient of the multiplier based on an amplification factor detected by an amplification factor detection unit. 5. In the electro-acoustic conversion characteristic of the horn speaker, a transfer function without distortion of the horn speaker is H1, a transfer function representing a second-order distortion is H2, and transfer functions of the horn speaker are H1 and H2. The amplification factor of the power amplifier is represented by A, the transfer function of the first filter is represented by G1, and the transfer function of the second filter is represented by G2.
And the transfer functions H1 and G1 expressed by using the frequency m as a parameter are H1 (m) and G1 (m), respectively.
And the transfer functions H2 and G2 are represented by a frequency m (where m =
mi + mj or a combination of m = | mi−mj |) as parameters,
(M1, m2), G2 (m1, m2), and the multiplication coefficient of the multiplier is α1, (Equation 2) (Equation 3) The horn loudspeaker system according to any one of claims 1 and 3, wherein the characteristics of the first and second filters and the multiplication coefficient α1 are set so as to satisfy the following. 6. The horn speaker system,
A transfer function of the horn speaker without distortion is H1,
A transfer function representing a second-order distortion is represented by H2, a transfer function of the horn speaker is represented by a parallel connection of H1 and H2, an amplification factor of the power amplifier is represented by A, and in the distortion removing device, Let the transfer function be G1, and let the transfer function of the second filter be G2
And the transfer functions H1 and G1 expressed by using the frequency m as a parameter are H1 (m) and G1 (m), respectively.
And the transfer functions H2 and G2 are represented by a frequency m (where m =
mi + mj or a combination of m = | mi−mj |) as parameters,
(M1, m2), G2 (m1, m2), and the multiplication coefficient of the multiplier is α2. (Equation 5) (Equation 6) The horn speaker system according to any one of claims 2 and 4, wherein