JPH08314471A - Muffler - Google Patents

Abstract

PURPOSE: To reduce actively a noise passing through a window of a room by providing a control means controlling a brake vibration generation means so that an interference sound becomes minimum based on the interference sound detected by an interference sound detection means and the noise detected by a noise detection means. CONSTITUTION: A noise source microphone 5 detects a sound outgoing from a sound generator 6 set up in the room. Vibration generators 3a, 3b vibrate a window glass 2. A detection microphone 7 detects the interference sound caused by the interference between the vibration generated from the vibration generators 3a, 3b and the sound generated from the sound generator 6. A control part 15 controls respective vibration generators 3a, 3b so that the interference sound becomes minimum based on the interference sound inputted by the detection microphone 7 and the noise inputted by the noise source microphone 5. Respective vibration generators 3a, 3b are constituted of a piezoelectric element (PZT) controlling the strength of the vibration by the strength of an electric signal, and are set up on the inside room side surface of the room glass 2 as a partition part parting the inside room and the outside room.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound insulation device capable of actively reducing noise transmitted through a window of a room.

[0002]

2. Description of the Related Art In recent years, the number of people who enjoy playing musical instruments and karaoke at home has increased. When making loud noises indoors, we take measures such as lowering the volume of music and closing windows so as not to make people outdoors feel uncomfortable. In some cases, a soundproof box made of a sound insulating material or a sound absorbing material was installed indoors.

On the other hand, noise generated outdoors (noise of cars, trains, etc.) is also transmitted indoors, and therefore, it is dealt with by closing windows or providing soundproof walls in some cases.

[0004]

However, the window glass used for houses has a small thickness and a small sound transmission loss. Therefore, there is a problem that the sound is transmitted through the window and leaks to the outside to make the neighbors uncomfortable and people living indoors feel uncomfortable. Further, the vibration accompanying the sound was generated in the window glass, and the sound and the vibration caused by the vibration also made the neighbor uncomfortable.

Further, there is a problem that the soundproof box and the soundproof wall require a lot of space and cost for installation.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a sound insulation device capable of actively reducing noise transmitted through a window of a room.

[0007]

In order to achieve this object, a sound insulation device of the present invention is a noise detecting means for detecting indoor or outdoor noise and installed in the vicinity of the noise source.
At least one control vibration generating unit that is disposed in a partition portion that distinguishes between the indoor and the outdoor and that generates a reverse vibration that cancels the vibration of the partition portion generated by the noise, and the noise with respect to the partition portion. Interference sound detecting means, which is disposed on the opposite side of the source and near the partition portion, detects an interference sound generated by the interference between the reverse vibration generated from the control vibration generating means and the noise passing through the partition portion. And a control means for controlling the control vibration generating means based on the interference sound detected by the interference sound detecting means and the noise detected by the noise detecting means so as to minimize the interference sound. I have it.

The interference sound detecting means may be provided in the number corresponding to the number of the control vibration generating means.

Further, a sound generated from a sound generator such as a stereo may be used as the noise, and a signal of the noise may be directly output from the sound generator to the control means.

Further, the noise detecting means and the interference sound detecting means are provided on the indoor side and the outdoor side, respectively, and a state in which the noise detecting means on the indoor side and the interference sound detecting means on the outdoor side operate and an outdoor side There may be provided switching means for selectively switching between a state in which the noise detecting means and the interference sound detecting means on the indoor side operate.

[0011]

According to the sound insulation device of the present invention having the above structure, the noise detected by the noise detecting means installed near the noise source inside or outside the room and the control vibration generating means detected by the interference sound detecting means The control means controls the control vibration generating means so that the interference sound with the generated reverse vibration is minimized, and the vibration reduces the interference sound.

Further, with respect to the interference sound detected by the interference sound detecting means dedicated to the control vibration generating means, which is installed in the vicinity of the control vibration generating means, the control means controls the respective control vibration generating means to make fine adjustments. Implement sound insulation.

Furthermore, a signal of a sound generated from a sound generator such as a stereo is directly output to the control means, and based on the signal and the interference sound detected by the interference sound detection means, the control means is The control vibration generating means is controlled.

With respect to the indoor noise source, the noise generated from the indoor noise source is brought into a state in which the indoor noise detecting means and the outdoor interference sound detecting means are activated by the switching means. Is transmitted through the partition part, and the interference sound between the transmitted noise and the reverse vibration generated by the control vibration generating means is detected by the interference sound detecting means on the outdoor side, and the detected interference sound and the indoor side are detected. The interference sound is reduced based on the noise detected by the noise detecting means. On the other hand, for the noise source on the outdoor side, the noise generated by the noise source on the outdoor side is divided by the switching means so that the noise detecting means on the outdoor side and the interference sound detecting means on the indoor side are activated. The interference sound of the transmitted noise and the reverse vibration generated by the control vibration generating means is detected by the interference sound detecting means on the indoor side, and the detected interference sound and the noise on the outdoor side are detected. The interference sound is reduced based on the noise detected by the detection means.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a sound insulation device embodying the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the structure of a sound insulation device. The sound insulation device of the present embodiment is a noise source microphone 5 for detecting a sound emitted from a sound generator 6 installed indoors.
And vibration generators 3a and 3b as control vibration generating means for vibrating the window glass 2 described later, and the vibration generators 3 described above.
a detection microphone 7 as interference sound detection means for detecting an interference sound generated by the interference between the vibrations generated by a and 3b and the sound generated by the sound generator 6, and the interference sound input by the detection microphone 7. And a control unit 15 as a control means for controlling each of the vibration generators 3a and 3b based on the noise input from the noise source microphone 5 so that the interference sound is minimized. Each of the vibration generators 3a and 3b is composed of a piezo element (PZT) capable of controlling the strength of vibration depending on the strength of an electric signal, and the indoor side of the window glass 2 as a partitioning portion that distinguishes the room from the outdoors. It is installed on the surface. The vibration generator 3
a and 3b are for reducing the sound generated from the sound generator 6 from being transmitted through the window glass 2 by the control unit 15 described later.

The detection microphone 7 is disposed on the outdoor surface of the window glass 2.

The noise source microphone 5 has a freely movable structure, and is arranged near the sound generator 6 in FIG.

Next, the configuration of the electric circuit 20 of this embodiment will be described.

The noise of the sound generator 6 detected by the noise source microphone 5 is amplified by an amplifier 11, and further, an A / D converter 14 for converting an analog signal into a digital signal.
Are converted into digital signals by. The digital signal is input to the control unit 15. On the other hand, the detection microphone 7
The interference sound detected by is amplified by the amplifier 9, further converted into a digital signal by the A / D converter 12, and input to the controller 15.

Based on the interference sound detected by the detection microphone 7 and the noise detected by the noise source microphone 5, the control section 15 minimizes the interference sound by each vibration generator. Control 3a and 3b. In the control unit 15, each D / A conversion unit 13 outputs the digital signal that minimizes the interference sound obtained by the method described later.
output to a and 13b. The digital signal corresponds to each D
The analog signals are converted into analog signals by the A / A converters 13a and 13b, and the analog signals are amplified by the amplifiers 10a and 10b connected to the D / A converters 13a and 13b, and controlled by the vibration generators 3a and 3b. It occurs as vibration.

Next, a method of minimizing the interference sound in the control unit 15 will be described in detail.

In the control section 15, as shown in FIG.
The minimum signal is obtained by a finite impulse response filter (also called FIR filter) that can easily have arbitrary characteristics. The input signal x (n) 200 is the detection signal of the noise source microphone 5 in FIG. 1, the symbol 201 is a delay element, the symbols W _0n , W _1n , W _2n , ..., W _Mn are variable filter coefficients, and the symbol is a symbol. Reference numeral 202 denotes an adder, symbol M denotes the number of taps of the filter, and the minimum signal is obtained as an output y (n) 204 by the following equation.

[0024]

[Equation 1]

The variable filter coefficients W _1n , W _2n , ..., W _Mn are used because they follow changes in the transfer characteristics due to disturbances in the noise path and changes in the characteristics of each electric component itself. This is because it converges to the optimum filter coefficient value.

Next, a method for obtaining the variable filter coefficient
This will be described with reference to FIG. Here, the noise of Fig. 1
The noise signal x (n) detected by the sound source microphone 5 is the delay filter 3
02, the reference signal c (n) is generated.
Be done. Detection of this reference signal c (n) and detection microphone 7
The signal e (n) is input to the adaptive algorithm 301, and
Possible using an adaptive formula called LMS algorithm
Variable filter coefficient W_1n, W _2n, ..., W_MnWill be updated.

[0027]

[Equation 2]

The parameter μ in the above equation is a constant called a step size, which is a parameter that influences the convergence speed and convergence accuracy of the filter coefficient W (n).

That is, in order to pursue the convergence speed, it is sufficient to increase the parameter μ within a converging range, but in consideration of the accuracy after convergence, it is necessary to comprehensively select the parameter μ.

As described above, the estimated variable filter coefficient
W _1n W _2n ... W _Mn are transmitted to A of FIG. 2 to generate the output digital signal y (n) 204.

The coefficient h _{0 of} the delay filter 302 shown in FIG.
h ₁ , ... H _p are obtained in advance. FIG. 4 is a block diagram showing the configuration of noise control used to obtain the coefficient of the delay filter 302. Random noise source 400 can provide a random signal. FIG. 4 is a diagram when the vibration generator 3a and the detection microphone 7 are used.

The overall operation of FIG. 4 will be described. A random digital signal is generated from the random noise generation source 400, and this drives the vibration generator 3a via the D / A conversion unit 13a and the amplifier 10a to generate control vibration.
On the other hand, the random noise generation source 400 outputs a random digital signal to the control unit 15. In the adder 403, picked up by the detection microphone 7, the amplifier 9, the A / D conversion unit 1
The noise signal via 2 and the output of the control unit 15 are added to obtain the error e (n).

The control unit 15 sequentially corrects the coefficient of the control unit 15 so as to minimize this error e (n). Finally, this convergence value is set to the filter coefficient h ₀ ,
It is used as h ₁ , ... H _p .

Next, the operation of the sound insulation device of this embodiment will be described with reference to FIG.

First, when the sound generated by the sound generator 6 in the room is input by the noise source microphone 5, the sound is amplified by the amplifier 11, and then the A / D converter 1
It is converted into a digital signal by 4 and input to the control unit 15. On the other hand, the interference sound near the outside that passes through the window glass 2 is input by the detection microphone 7 and amplified by the amplifier 9. Then, it is input to the control unit 15 via the A / D conversion unit 12.

In the control unit 15, the vibration generators 3a, 3a for generating control vibration for exciting the window glass 2 from the detection microphone 7 are provided.
The noise and vibration generator 3a passing through the window glass 2 is based on the transfer function showing the characteristics of the electric components up to b, the amplifiers 10a and 10b, the A / D converter 12, the D / A converters 13a and 13b, and the like. The filter coefficient W (n) is determined so that the interference sound due to the interference with the vibration generated from 3b is minimized.

Further, the control unit 15 generates a digital signal having an amplitude characteristic and a phase characteristic which minimizes the interference sound, based on the noise signal input by the noise source microphone 5 and the filter coefficient W _Mn. . The digital signal is converted into an analog signal by each of the D / A converters 13a and 13b, and then amplified by each of the amplifiers 10a and 10b to generate a control vibration for canceling the interference sound from each of the vibration generators 3a and 3b. The sound generated and transmitted by the sound generator 6 can be reduced.

As is clear from the above description, the sound insulation device according to the present embodiment generates the noise detected by the noise source microphone 5 installed near the sound generator 6 in the room and the vibration detected by the detection microphone 7. Since the control unit 15 controls the vibration generators 3a and 3b so that the interference sound with the control vibration generated from the devices 3a and 3b is minimized, the sound transmitted through the window glass 2 is reduced by the reverse vibration. It is possible to reduce discomfort caused by noise given to a neighbor or the like.

The present invention is not limited to the embodiments described above in detail, and within the scope of the invention,
Various changes can be made. For example, in this embodiment, the sound of the indoor sound generator 6 is prevented from passing through the window glass 2. However, as shown in FIG. 5, the sound generator 6 is configured to be compatible with indoor and outdoor noise sources. May be. In this case, the indoor noise source microphone 5a is used as the noise detecting means.
Is arranged near the sound generator 6 and the outdoor noise source microphone 5b is arranged near the external noise source 30, and each of the noise source microphones 5a and 5b is connected to the first changeover switch 31 which can be selectively selected. . On the other hand, the indoor detection microphone 7b as the interference sound detecting means is arranged near the indoor surface of the window glass 2, and the outdoor detection microphone 7a is arranged near the outdoor surface of the window glass 2 to detect each detection microphone 7a. , 7b are connected to the second changeover switch 32 which can be selected alternatively. Further, in the case of such a configuration, the delay filter coefficient when the indoor noise source microphone 5a and the outdoor detection microphone 7a are used and the delay filter coefficient when the outdoor noise source microphone 5b and the indoor detection microphone 7b are used It is necessary to obtain the coefficient and the coefficient by the method described above.

The operation of the sound insulation device thus configured will be described with reference to FIG.

If the noise source is the outdoor noise source 30, the first changeover switch 31 is set to the outdoor noise source microphone 5.
b, and the second changeover switch 32 is set to the indoor detection microphone 7b. Then, the noise generated from the outdoor noise source 30 is detected by the outdoor noise source microphone 5b. The detected noise is amplified by the amplifier 11, and then converted into a digital signal by the A / D converter 14 and input to the controller 15.

In the control section 15, the electric components from the indoor detection microphone 7b to the vibration generators 3a and 3b for generating the control vibration for exciting the window glass 2, the amplifiers 10a and 10b,
Interference due to interference between the sound transmitted through the window glass 2 and the vibration generated from the vibration generators 3a and 3b based on the transfer function indicating the characteristics of the A / D conversion unit 12, the D / A conversion units 13a and 13b, and the like. The filter coefficient W (n) is determined so that the sound is minimized.

Further, the control unit 15 generates a digital signal having an amplitude characteristic and a phase characteristic which minimizes the interference sound, based on the noise signal input by the outdoor noise source microphone 5b and the filter coefficient W _Mn. To do. The digital signal is converted into an analog signal by the D / A converters 13a and 13b, then amplified by the amplifiers 10a and 10b, and reverse vibration for canceling the interference sound is generated from the vibration generators 3a and 3b. It is possible to prevent the noise generated from the external noise source 30 from penetrating into the room through the window glass 2.

On the other hand, in order to prevent the noise on the indoor side from leaking outside, the first changeover switch 31 is set to the indoor noise source microphone 5a and the second changeover switch 32 is set to the outdoor side detection microphone 7a. . In this case, the configuration is the same as that of the above-described embodiment, and thus the description of the operation is omitted.
In this way, it is possible to reduce the penetration of indoor noise and outdoor noise through the window glass 2.

In the above configuration, the user switches the first changeover switch 31 and the second changeover switch 32. However, by changing one changeover switch, the other changeover switch is automatically changed. It may be configured to switch.

Further, in this embodiment, the sound of the music generator 6 is input through the noise source microphone 5, but the output signal of the sound generator 6 may be sent to the control unit 15. Therefore, the noise source microphone 5 can be omitted. In this case, the output signal from the sound generator 6 is amplified by the amplifier 11, further converted into a digital signal by the A / D conversion unit 14, and then input to the control unit 15.

Further, in this embodiment, two vibration generators 3a and 3b are provided as the control vibration generating means, but the number may be further increased. Further, in this case, the same number of detection microphones as interference sound detection means are provided corresponding to the number of speakers, and the control unit 15 minimizes the interference sound detected by the respective detection microphones. May control the vibration generator. Alternatively, the interference sounds detected by the respective detection microphones may be combined, and the control unit 15 may control the vibration generator so that the combined sound is minimized.

In the control unit 15, when the digital signal value of the noise detected by the noise source microphone 5 exceeds a predetermined value, for example, 50 dB at which it feels quiet, each D / A converter 13a, 13b. It is also possible to output a reverse vibration signal that minimizes the interference sound, and prevent the reverse vibration from being generated from the vibration generators 3a and 3b when it does not exceed 50 dB. In this case, it is possible to save electric power for operating the vibration generators 3a and 3b when there is no risk of intrusion or leakage to the outside, that is, when there is no need to insulate sound, and the vibration generator 3a can be saved. ,
The durability of 3b can be improved.

Further, in this embodiment, the vibration generators 3a, 3a
Although PZT is used as b, a device that can generate vibration by an electric signal, such as a vibrator using a coil and a permanent magnet, may be used.

Further, in the present embodiment, the detection microphone 7 is used as the interference sound detecting means, but any device capable of detecting vibration may be used, for example, an acceleration pickup used for vibration analysis or the like is used. May be.

[0051]

As is apparent from the above description, the sound insulation device of the present invention has the noise detected by the noise detection means installed in the vicinity of the noise source indoors or outdoors and the control detected by the interference sound detection means. The control means controls the control vibration generating means so that the interference sound with the reverse vibration generated from the vibration generating means is minimized, and the interference sound is reduced by the reverse vibration. The discomfort of can be reduced.

Since the control means controls the respective control vibration generating means with respect to the interference sound detected by the interference sound detecting means dedicated to the control vibration generating means, which is installed in the vicinity of the control vibration generating means, Fine sound insulation can be implemented.

Furthermore, a signal of a sound generated from a sound generator such as a stereo is directly output to the control means, and based on the signal and the interference sound detected by the interference sound detection means, the control means Since the control vibration generating means is controlled, the noise of only the noise source can be reduced.

With respect to the noise source on the indoor side, the noise generated by the noise source on the indoor side is set by the switching means so that the noise detecting means on the indoor side and the interference sound detecting means on the outdoor side operate. Is transmitted through the partition part, and the interference sound between the transmitted noise and the reverse vibration generated by the control vibration generating means is detected by the interference sound detecting means on the outdoor side, and the detected interference sound and the indoor side are detected. The interference sound is reduced based on the noise detected by the noise detection means of, while the noise source on the outside is:
The noise generated from the noise source on the outdoor side is transmitted through the partition portion while the noise detection means on the outdoor side and the interference sound detection means on the indoor side are operated by the switching means, and the transmitted noise, and The interference sound with the reverse vibration generated by the control vibration generating means is detected by the interference sound detecting means on the indoor side, based on the detected interference sound and the noise detected by the noise detecting means on the outdoor side, Since the interference sound is reduced, it is possible to obtain an effect such that the noise can be prevented from passing through the partition portion with respect to a noise source inside or outside the room.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a sound insulation device that insulates noise in a room.

FIG. 2 is a block diagram for generating a control sound in the control unit of the present embodiment.

FIG. 3 is a block diagram for obtaining a filter coefficient used when generating a control sound according to the present embodiment.

FIG. 4 is a block diagram showing a configuration of noise control used for obtaining a coefficient of a delay filter.

FIG. 5 is a block diagram showing a configuration of a sound insulation device that insulates indoor and outdoor noise.

[Explanation of symbols]

 2 Window glass 3a Vibration generator 3b Vibration generator 5 Noise source microphone 6 Sound generator 7 Detection microphone 15 Control unit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H03H 21/00 G10K 11/16 D

Claims (4)

[Claims] 1. A noise detecting means for detecting indoor or outdoor noise and being installed in the vicinity of the noise source, and a noise detecting means arranged in a partition part for distinguishing the indoor from the outdoor and generated by the noise. At least one control vibration generating means for generating a reverse vibration for canceling the vibration of the partition part, and on the opposite side of the noise source with respect to the partition part,
An interference sound detecting unit that is disposed near the partition portion, detects an interference sound generated by the interference of the reverse vibration generated from the control vibration generating unit, and the noise that passes through the partition portion, and the interference sound detecting unit. Based on the detected interference sound and the noise detected by the noise detection means, there is provided a control means for controlling the control vibration generation means so as to minimize the interference sound. apparatus. 2. The sound insulation device according to claim 1, further comprising a number of the interference sound detectors corresponding to the number of the control vibration generators. 3. The sound generated from a sound generator such as a stereo is used as the noise, and a signal of the noise is directly output from the sound generator to the control means. Sound insulation device described. 4. The noise detecting means and the interference sound detecting means are respectively provided on the indoor side and the outdoor side, and a state in which the noise detecting means on the indoor side and the interference sound detecting means on the outdoor side operate and an outdoor side The sound insulation device according to claim 1, further comprising a switching unit that selectively switches between a state in which the noise detection unit and the interference sound detection unit on the indoor side operate.