JPH09230876A - Noise eliminating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a noise eliminating device capable of reducing unpleasantness even in the case of long time wearing by constituting the device so that as acoustic structure part is in non-contact with ears when it is mounted on a head of human body. SOLUTION: In this device, a feedback control system is constituted of a detection means 1 to convert sound wave into an electrical signal and output it as an evaluation signal, an arithmetic operation means 2 to perform an operation based on the evaluation signal and output a control signal, and a control means 3 to convert the control signal into sound wave and output it as control sound. In this case, at least, an acoustic structure part SS provided with the detection means 1 and the control means is mounted on a head of a human body by a jig 10, and the acoustic structure part SS is fitted in noncontact with the ears of the human body by the jig 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silencer,
More specifically, the present invention relates to a head-mounted silencer that reduces noise by outputting a control sound.

[0002]

2. Description of the Related Art FIG. 11 shows a configuration example of a conventional silencer. This silencer is composed of a detection means 1, a calculation means 2 and a control means 3. The detection means 1 is a means for converting a sound wave into an electric signal and outputting it as an evaluation signal,
The sound waves detected by the detection means 1 are the noise 6 from the outside and the control sound from the control means 7. The calculation unit 2 is a unit that performs a predetermined calculation based on the evaluation signal 5 from the detection unit 1 and outputs the control signal 5.
The control unit 3 is a unit that converts the control signal from the calculation unit 2 into a control sound 7 and outputs the control sound 7. Therefore, the detection means 1, the calculation means 2 and the control means 3 constitute a feedback control system. The control means 3 outputs a control sound having a phase opposite to that of the sound wave detected by the detection means 1 and cancels the noise to mute the sound.

Such a conventional silencer is composed of an acoustic structure section SS having at least the detection means 1 and the control means 3, and a jig 10 for installing the acoustic structure section SS on the head. When the acoustic structure section SS is installed on the head, the acoustic structure section SS comes into contact with the user's ear to reduce the intrusion of noise 6 from the outside.

[0004]

As described above, the conventional silencer is installed on the human head so that the acoustic structure contacts the ear. For this reason, there has been a problem that when the muffler is worn for a long time, the user feels a lot of discomfort. The present invention has been made in view of the above circumstances, and when installed on the human head, an acoustic structure is in a state of non-contact with the ears, and a muffling device that reduces discomfort during long-time wearing. The purpose is to provide.

[0005]

According to a first aspect of the present invention, there is provided a sound deadening device which converts a sound wave into an electric signal and outputs the electric signal as an evaluation signal, and a calculation unit based on the evaluation signal. A silencer that forms a feedback control system with a computing unit that outputs a signal and a control unit that converts the control signal into a sound wave and outputs it as a control sound, and includes at least the detection unit and the control unit. The acoustic structure is installed on the human head by a jig, and the acoustic structure is installed by the jig in a non-contact manner with the human ear.

A muffler according to a second aspect of the present invention is the muffler according to the first aspect of the present invention, wherein the arithmetic means is configured as an arithmetic circuit including at least a resistance element. All or part of the resistance element is configured as a variable resistor, and by adjusting the variable resistor, the calculation performed by the calculation means is adjusted.

The muffler according to the present invention as defined in claim 3 is the muffler according to the present invention as set forth in claim 1, wherein the computing means includes a plurality of computing circuits for performing different computations, respectively. And a switching means for selecting one of the arithmetic circuits. The switching means selects and uses one of the arithmetic circuits.

The muffler according to the present invention as defined in claim 4 is the muffler according to the present invention as defined in claim 1, wherein the sound and vibration output from the control means are converted into electrical signals and used as detection signals. A detecting means for outputting, a second calculating means for performing a calculation based on the detected signal, and outputting a second control signal, and a second control signal for synthesizing the second control signal with the control signal output by the calculating means. And a synthesizing means.

According to a fifth aspect of the present invention, there is provided a silencer device according to the second aspect of the present invention, which is provided with automatic tuning means for performing calculation based on the evaluation signal output from the detecting means. The automatic tuning means is configured to automatically adjust the resistance value of the variable resistor of the computing means. A silencer according to the present invention described in claim 6 is the silencer according to the present invention according to claim 3, comprising automatic tuning means for performing calculation based on the evaluation signal output from the detection means, and the automatic tuning described above. The means is configured to automatically switch the switching means of the computing means.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of the construction of a silencer according to the present invention as set forth in claim 1. This muffler is composed of an acoustic structure SS and a jig 10 that supports the acoustic structure SS. The jig 10 is provided with a pad 11, and the pad 11 is arranged so as to come into contact with the human head when the pad 11 is installed on the human head.

When installing this silencer on the human head,
The pad 11 fixes the jig 10 to the human head, and the acoustic structure SS is brought into non-contact with the human ear. For example, the detecting means 1 is about 20 from the ear canal entrance.
cm, and the control means 3 is installed on the human head so that it is about 30 cm from the entrance of the external auditory meatus. The pad 11 is formed of an elastic material in order to prevent discomfort to the human head, and is formed in a shape having a thickness for keeping the acoustic structure section SS in a non-contact state with the ear.

Further, this silencer comprises a detecting means 1, a calculating means 2 and a controlling means 3, and the detecting means 1 and the controlling means 3 are provided in the acoustic structure section SS.
The detection unit 1 is a unit that converts a sound wave in the acoustic structure into an electric signal and outputs it as an evaluation signal. Calculation means 2
Is a means for performing a predetermined calculation based on the evaluation signal 5 from the detection means 1 and outputting the control signal 5, and can be configured as a filter circuit. The control unit 3 is a unit that converts the control signal from the calculation unit 2 into a control sound 7 and outputs the control sound 7. That is, the detection means 1, the calculation means 2 and the control means 3 constitute a feedback control system.

FIG. 2 is a diagram showing an example of the transfer characteristic of the controlled object 8, (a) in the figure showing the gain characteristic, and (b) showing the phase characteristic. Is. Regarding the transfer characteristic of the controlled object 8, the phase delay has a gradual increase in phase delay as the frequency increases, and the gain characteristic has a gradual increase in gain as the frequency increases.

In such a muffler, 100 Hz to
A case where noise reduction is performed for 500 Hz noise will be described. FIG. 3 is a diagram showing an example of the transfer characteristic of the calculation means 2, in which (a) shows the gain characteristic and (b) shows the phase characteristic. The phase characteristic of this computing means 2 is
Around 400 Hz, there is almost no phase shift in a range lower than this, but a phase delay occurs in a range beyond this.

FIG. 4 shows the muting volume of the controlled object 8 shown in FIG. 2 when the computing means 2 shown in FIG. 3 is used. The mute volume is the ratio of the evaluation signal 4 when the control means 3 is not outputting a control sound and the evaluation signal 4 when the control means 3 is outputting a control sound, and FIG. It is the figure which showed the frequency characteristic of quantity. From this figure, about 10
It can be seen that muffling is performed in the range of 0 Hz to 600 Hz.

Therefore, it is possible to reduce the discomfort of the wearer when the silencer is worn for a long time. FIG. 5 shows an example of the configuration of the silencer according to the present invention as defined in claim 2. In this silencer, the arithmetic means 2 shown in FIG. 1 is configured as an arithmetic circuit configured to include at least a resistance element, and all or some of these resistance elements are configured as a variable resistor 12. .

As an example of the configuration of the computing means 2, the content of the computation is represented by the transfer function H (s) in the following equation (1).

[0018]

[Equation 1]

Where wo, Q, H1 and H2 in the above equation
Is

[0020]

[Equation 2]

Where R1 and R2 are resistance values, C1 and C2
Is the capacitance of the capacitor. When such an arithmetic circuit is used, the resistance element that gives the resistance values R1 and R2 can be configured as the variable resistor 12, and the silencing characteristic can be adjusted according to the noise. Therefore, it is possible to adjust the characteristics of the calculation means 2 in accordance with the environment in which the silencer is used to obtain a more desirable silencing effect, and reduce the discomfort of the wearer when the silencer is worn for a long time. be able to.

FIG. 6 shows an example of the construction of the silencer according to the third aspect of the present invention. In this silencer, the arithmetic means 2 shown in FIG. 1 is composed of a plurality of arithmetic circuits 20 to 2n and a switching means 14 for selecting one of these arithmetic circuits. The switching means 14 may be any means for selecting any one of the arithmetic circuits 20 to 2n, and may be a mechanical switch such as a rotary switch or a slide switch, or an electronic switch using a switching element. May be.

Each of the n arithmetic circuits 20 to 2n is a circuit for executing a different arithmetic operation, and the switching means 14 is used.
And a feedback control system together with the detection means 1 and the control means 3. By the switching means 14,
FIG. 7 shows an example of the muting volume when each of the arithmetic circuits 20 to 2n is selected. (A)-(n) in the figure is a diagram showing an example of frequency characteristics of the silence volume in each case.
(A) in the figure shows the case where the arithmetic circuit 20 is selected,
(B) shows the case where the arithmetic circuit 21 is selected, and (n) shows the case where the arithmetic circuit 2n is selected.

When the arithmetic circuit 20 is selected, the frequency band that can be muted (silence frequency band) is approximately 100 Hz.
When the arithmetic circuit 21 is selected, the silencing frequency band is approximately 100 Hz to 600 Hz, and when the arithmetic circuit 21 is selected, the silencing frequency band is approximately 800 Hz to 1300 Hz. Therefore, it becomes possible to adjust the characteristics of the calculation means 2 in accordance with the environment in which the silencer is used to obtain a more desirable silencing effect, and reduce the discomfort of the wearer when the silencer is worn for a long time. be able to.

FIG. 8 shows an example of the construction of the silencer according to the fourth aspect of the present invention. This silencer is configured by further providing the silencer shown in FIG. 1 with a second detecting means 15 provided in the control means 3, a second computing means 16, and a control signal synthesizing means 30. To be done. The second detection means 15 is attached to the speaker as the control means 3, converts the vibration of the cone paper into an electric signal, and outputs it as a detection signal 17. The second calculation means 16 calculates based on the detection signal 17 and outputs the second control signal 1
8 is output. The synthesizing means 30 is means for synthesizing the control signal 5 output from the computing means 2 and the second control means 18 output from the second computing means 16 and inputting the synthesized signal to the control means, and is configured by an analog adder. can do.

FIG. 9 shows the silencer shown in FIG.
A transfer system from the output of the synthesizing means 30 to the detection signal 17 of the second detection means 15 is a block 22, its transfer function is a function C1, and a transfer system from the detection signal 17 to the control sound 7 is a block 23. The transfer function is shown as a function C2. In this figure, the detection signal 17 output from the block 22 is output to the block 2 by the second arithmetic means 15.
It is fed back to 2 and forms a loop.

Therefore, if the control target 8 is the control target 19 to which the second calculation means 15 is added, and its transfer function is Ce, then this function Ce is

[0028]

(Equation 3)

It can be expressed as Where the transfer function C
Is a controlled object 8 including a block 22 and a block 23
And the transfer function H3 is the transfer function of the calculating means 16. The calculation means 2 may perform a calculation on the expanded control target 19 so that the control system is stable and a desired noise reduction effect is obtained with respect to noise. Therefore, a more desirable control system can be designed when designing a silencer that reduces the discomfort of the wearer when wearing the silencer for a long time.

FIG. 10 shows an example of the construction of the silencer according to the present invention as defined in claims 5 and 6. This silencer is configured by further providing automatic tuning means T to the silencer shown in FIG. 5 or FIG. The automatic tuning means T adjusts the calculation in the calculation means 2 based on the evaluation signal 4 output from the detection means 1. That is, the automatic tuning means T converts the evaluation signal 4 into a noise level, obtains its overall value, and adjusts the computing means 2 so that this overall value is minimized.

Here, the evaluation signal 4 is the sound pressure level (dB) detected by the detection means 3, but the way humans perceive noise is different for each frequency band. Therefore, each sound pressure level for each frequency is individually sensuously corrected to obtain a noise level (dB (A)). The automatic tuning means T finds the sum of the noise levels for each frequency as an overall value, and adjusts the computing means 2 so that this value is minimized.

In the case of the silencer shown in FIG. 5, the calculation means 2
Is configured to include the variable resistor 12, the automatic tuning means T automatically adjusts the calculation in the calculating means 2 by changing the resistance value of the variable resistor 12, thereby achieving a more desirable muffling. The effect can be obtained.
Further, in the case of the silencer shown in FIG. 6, since the arithmetic means 2 is composed of a plurality of arithmetic circuits 20 to 2n and the switching means 14, the automatic tuning means T automatically switches the switching means. This makes it possible to automatically adjust the calculation in the calculating means 2 and obtain a more desirable silencing effect.

In this way, according to the target noise,
It is possible to provide a muffling device that automatically obtains a desired muffling effect and reduces the discomfort of the wearer when the muffling device is worn for a long time.

[0034]

According to the sound deadening device of the present invention described in claim 1, even when it is installed on the human head, the acoustic structure is in a state of non-contact with the human ear, so that it can be used for a long time. The discomfort of the wearer with respect to the wearing can be reduced. That is, it is possible to provide a head-mounted silencer that reduces discomfort caused by wearing for a long time.

In the muffler according to the present invention as defined in claim 2, the calculating means includes a variable resistor, and the muffling characteristic of the muffler can be adjusted by adjusting the variable resistor. . Therefore, it is possible to provide a head-mounted silencer that can obtain a desired silencing effect according to the target noise and reduce discomfort when worn for a long time.

In the muffler according to the present invention as set forth in claim 3, the calculation means is composed of a switching means and a plurality of calculation circuits. By switching the calculation circuits by the switching means, the muffling characteristics of the muffler are adjusted. be able to.
Therefore, it is possible to provide a head-mounted silencer that can obtain a desired silencing effect according to the target noise and reduce discomfort when worn for a long time.

In the silencer according to the present invention as defined in claim 4, the detecting means and the feedback loop by the second calculating means are provided to facilitate the design of the calculating means. Therefore, a more desirable control system can be designed when designing a silencer that reduces the discomfort of the wearer when wearing the silencer for a long time. In the muffler according to the present invention as set forth in claim 5, the automatic tuning means automatically changes the resistance value of the variable resistor based on the evaluation signal to automatically adjust the arithmetic means, which is more preferable. A muffling effect can be obtained.

Therefore, it is possible to provide a muffling device which automatically obtains a desired muffling effect in accordance with the target noise and reduces the discomfort of the wearer when the muffling device is worn for a long time. In the muffler according to the present invention as set forth in claim 6, the automatic tuning means, based on the evaluation signal,
By automatically switching the switching means, it is possible to automatically adjust the computing means and obtain a more desirable silencing effect.

Therefore, it is possible to provide a muffling device which automatically obtains a desired muffling effect according to the target noise and reduces the discomfort of the wearer when the muffling device is worn for a long time.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration example of a silencer according to the present invention as set forth in claim 1.

FIG. 2 is a diagram showing an example of a transfer characteristic of a controlled object 8 shown in FIG.

FIG. 3 is a diagram showing an example of a transfer characteristic of a calculation means 2 shown in FIG.

FIG. 4 is a diagram showing a sound deadening level when the calculation means 2 shown in FIG. 3 is used for the controlled object 8 shown in FIG. 2.

FIG. 5 is a diagram showing a configuration example of a silencer according to the present invention as defined in claim 2;

FIG. 6 is a diagram showing a configuration example of a silencer according to the present invention as defined in claim 3;

FIG. 7 is a diagram showing an example of the volume of silence when each of the arithmetic circuits 20 to 2n is selected by the switching means.

FIG. 8 is a diagram showing a configuration example of a silencer according to the present invention as defined in claim 4;

FIG. 9 is a block diagram of the silencer shown in FIG.

FIG. 10 is a diagram showing a configuration example of a silencer according to the present invention as defined in claims 5 and 6.

FIG. 11 is a diagram showing a configuration example of a conventional silencer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Detection means 2 ... Calculation means 3 ... Control means 4 ... Evaluation signal 5 ... Control signal 7 ... Control sound 10 ... Jig SS ... Acoustic structure part 12・ ・ ・ Variable resistor 14 ・ ・ ・ Switching means 15 ・ ・ ・ Detecting means 16 ・ ・ ・ Second arithmetic means 20 to 2n ・ ・ ・ Multiple arithmetic circuits 30 ・ ・ ・ Synthesis means T ・ ・ ・ Automatic tuning means

Claims (6)

[Claims] 1. A detecting means for converting a sound wave into an electric signal and outputting it as an evaluation signal, a calculating means for performing a calculation based on this evaluation signal and outputting a control signal, and a converting means for converting the control signal into a sound wave. In a silencer that constitutes a feedback control system with a control unit that outputs as a control sound, an acoustic structure unit including at least the detection unit and the control unit is installed on a human head by a jig, and the acoustic structure A silencer, wherein the part is installed by the jig in a non-contact manner with a human ear. 2. The silencer according to claim 1, wherein the arithmetic means is configured as an arithmetic circuit including at least a resistance element, and the resistance element is wholly or partly a variable resistor. A silencer characterized in that the calculation performed by the calculation means is adjusted by adjusting the variable resistor. 3. The silencer according to claim 1, wherein the arithmetic means comprises a plurality of arithmetic circuits each performing different arithmetic operations, and a switching means for selecting one of these arithmetic circuits. A silencer characterized in that any one of the arithmetic circuits is selected and used by the switching means. 4. The silencer according to claim 1, wherein the sound and vibration output from the control means are converted into an electric signal and output as a detection signal, and a calculation is performed based on the detection signal. A silencer comprising: a second arithmetic means for outputting a second control signal; and a synthesizing means for synthesizing the second control signal with the control signal output by the arithmetic means. . 5. The silencer according to claim 2, further comprising: automatic tuning means for performing calculation based on the evaluation signal output from the detecting means, wherein the automatic tuning means is the resistance of the variable resistor of the calculating means. A muffling device characterized by automatically adjusting the value. 6. The silencer according to claim 3, further comprising automatic tuning means for performing calculation based on an evaluation signal output from the detecting means, wherein the automatic tuning means automatically changes the switching means of the calculating means. A silencer characterized by switching to.