JP2014153668A - Ultra-low frequency sound reduction method and ultra-low frequency sound reduction device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively reduce an influence of an ultra-low frequency sound on an object with simple configurations.SOLUTION: A microphone 14 detects information related to a first ultra-low frequency sound S1. A signal processing part 16 generates a signal of a phase reverse to that of a first ultra-low frequency sound S1 on the basis of the information detected by the microphone 14. The controller 18 allows sound generation means 20 to generate a second ultra-low frequency sound S2 of a phase reverse to that of the first ultra-low frequency sound S1 which is large enough to offset the first ultra-low frequency sound S1 by driving the sound generation means 20 on the basis of the signal supplied from the signal processing part 16. The sound generation means 20 is arranged such that the first ultra-low frequency sound S1 during the transmission of the second ultra-low frequency sound S2 from a diesel engine 2A to an object 4 is oriented. The first ultra-low frequency sound S1 and the second ultra-low frequency sound S2 offset each other at a place in front of the object 4 so that the ultra-low frequency sound can be reduced.

Description

  The present invention relates to an ultra-low frequency sound reduction method and an ultra-low frequency sound reduction device for reducing ultra-low frequency sound generated from an ultra-low frequency sound source.

In the shield method, for example, in the muddy water type shield method, the excavated soil or muddy water generated in the tunnel is fluid-transferred to the vibrating screen device installed on the ground outside the tunnel through the drainage pipe, and the soil and sand are removed by the vibrating screen device. Separated into water containing silt clay (see Patent Document 1). Alternatively, in the earth pressure type shield method, excavated soil generated in the tunnel is pumped to the vibrating screen installed on the ground outside the tunnel through the exhaust pipe, and separated into water containing earth and sand and silt clay by the vibrating screen. To do.
Sediment is used for reclamation and the like, and water containing silt clay is treated by a treatment facility, and then fluid is transferred again into the tunnel through a mud pipe.
The vibration sieving device is an ultra-low frequency sound source that generates an ultra-low frequency sound of about 16 Hz in accordance with the operation of vibrating the sieve.
If there is a general house within the reach of ultra-low frequency sound, there will be a problem that furniture such as windows and doors of the house vibrate.
For this reason, conventionally, a concrete sound insulation chamber having a thickness of about 30 cm is constructed so as to surround the vibration sieving device, thereby reducing vibration due to ultra-low frequency sound.

JP 2012-12771 A

However, when a concrete sound insulation room is used, not only a great deal of labor and cost is required for its construction and dismantling, but it is also necessary to deal with environmental problems such as noise and waste disposal during dismantling.
In addition, equipment other than vibrating screen devices, such as diesel engines, air compressors, vibratory conveyors, vacuum pumps, etc. installed in factory buildings also generate ultra-low frequency noise, so ultra-low frequency sound is nearby. It is necessary to take measures to reduce the impact on the house.
However, the construction of a concrete sound insulation room in the same manner as described above requires a large space occupied in the building, and requires a large amount of equipment and increases costs.
The present invention has been made in view of such circumstances, and an object of the present invention is to be able to effectively reduce the influence of the ultra-low frequency sound of the ultra-low frequency sound generation source on the object with a simple configuration. An object of the present invention is to provide a low-frequency sound reduction device and a very low-frequency sound reduction method.

In order to achieve the above-mentioned object, an ultra-low frequency sound reduction method of the present invention is a method for reducing the influence of a first ultra-low frequency sound generated from an ultra-low frequency sound generation source on an object. Sound generating means for generating two ultra-low frequency sounds, and directing the second ultra-low frequency sound generated from the sound generating means to the object and the ultra-low frequency sound generation source, Directing to the first ultra-low frequency sound on the way from the ultra-low frequency sound generation source to the object, detecting information about the first ultra-low frequency sound, as the second ultra-low frequency sound, Based on the detected information, an ultra-low frequency sound having a phase opposite to that of the first ultra-low frequency sound sufficient to cancel the first ultra-low frequency sound is generated from the sound generating means.
The ultra-low frequency sound reduction method of the present invention is a method for reducing the influence of the first ultra-low frequency sound generated from the ultra-low frequency sound generation source on the object, and the second ultra-low frequency sound. Sound generating means for generating the second low frequency sound generated from the sound generating means without directing to the object, directing to the ultra low frequency sound generating source, Information on the very low frequency sound is detected, and the second very low frequency sound is opposite to the first very low frequency sound that is sufficient to cancel the first very low frequency sound based on the detected information. A very low frequency sound having a phase is generated from the sound generating means.
An ultra-low frequency sound reducing apparatus of the present invention is an ultra-low frequency sound reducing apparatus that reduces the influence of a first ultra-low frequency sound generated from an ultra-low frequency sound source on an object. Detecting means for detecting information relating to the first ultra-low frequency sound generated from the frequency sound source; generating a second ultra-low frequency sound; and Sound generating means arranged not to be directed to the generation source and the object, but to be directed to the first ultra-low frequency sound on the way from the ultra-low frequency sound generation source to the object; As the second ultra-low frequency sound, an ultra-low frequency sound having a phase opposite to that of the first ultra-low frequency sound, which is sufficient to cancel the first ultra-low frequency sound based on the detected information, is obtained from the sound generating means. And a control means for generating.
An ultra-low frequency sound reducing apparatus according to the present invention is an ultra-low frequency sound reducing apparatus that reduces the influence of a first ultra-low frequency sound generated from an ultra-low frequency sound generating source on an object. Detecting means for detecting information relating to the first ultra-low frequency sound generated from the wave sound source; generating the second ultra-low frequency sound; and directing the second ultra-low frequency sound toward the object. And the sound generating means arranged to be directed to the ultra-low frequency sound source, and the first ultra-low frequency sound based on the detected information as the second ultra-low frequency sound. Control means for generating from the sound generating means an ultra-low frequency sound having a phase opposite to that of the first ultra-low frequency sound sufficient to cancel.

According to the present invention, based on the information about the first ultra-low frequency sound generated from the ultra-low frequency sound source, the first ultra-low frequency sound having an opposite phase to the first ultra-low frequency sound is sufficient to cancel the first ultra-low frequency sound. On the way from the very low frequency sound source to the object without generating the second very low frequency sound from the sound generating means and directing the second very low frequency sound to the object and the very low frequency sound source In order to direct to the first ultra-low frequency sound, the first ultra-low frequency sound and the second ultra-low frequency sound cancel each other at a location in front of the object, thereby reducing the ultra-low frequency sound.
Therefore, the influence of the ultra-low frequency sound of the ultra-low frequency sound generation source on the object can be effectively reduced with a simple configuration.
Further, according to the present invention, based on the information about the first ultra-low frequency sound generated from the ultra-low frequency sound source, it is opposite to the first ultra-low frequency sound that is sufficient to cancel the first ultra-low frequency sound. The first ultra-low frequency sound is generated from the sound generating means and the second ultra-low frequency sound is directed to the ultra-low frequency sound generation source without being directed to the object. The very low frequency sound is reduced by canceling the sound and the second very low frequency sound near each other in the vicinity of the very low frequency sound generation source.
Therefore, the influence of the ultra-low frequency sound of the ultra-low frequency sound generation source on the object can be effectively reduced with a simple configuration.

It is a figure which shows the structure of 10 A of ultra low frequency sound reduction apparatuses of 1st Embodiment. It is a block diagram which shows the structure of the control system of 10 A of ultra-low frequency sound reduction apparatuses of 1st Embodiment. It is a perspective view which shows the external appearance of the subwoofer unit 22 which comprises the sound generation means 20 of 1st Embodiment. It is a diagram which shows an example of the characteristic of the frequency versus sound pressure of the very low frequency sound which the sound generation means 20 generate | occur | produces. (A)-(C) are explanatory drawings of the principle which cancels a very low frequency sound. It is a figure which shows the structure of the ultra-low frequency sound reduction apparatus 10B of 2nd Embodiment. It is a figure which shows the structure of 10 C of ultra-low frequency sound reduction apparatuses of 3rd Embodiment.

(First embodiment)
Next, an ultra-low frequency sound reduction method together with an ultra-low frequency sound reduction device according to an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, in the present embodiment, a case will be described in which the ultra-low frequency sound generation source is a diesel engine 2 </ b> A as equipment installed and used inside a building 12 such as a factory.
In the vicinity of the building 12, there is an object 4 such as a house or facility that is affected by the first ultra-low frequency sound S1 generated from the diesel engine 2A.
As shown in FIGS. 1 and 2, the ultra-low frequency sound reduction device 10 </ b> A includes a building 12, a microphone 14 (detection unit), a signal processing unit 16, a controller 18, a sound generation unit 20, and an enclosure 26. It is comprised including.

In the building 12, the entire side area and the entire upper area are closed by a sound-insulating wall. That is, the building 12 includes a sound-insulating side wall 1202 (wall portion) and a sound-insulating roof 1204 (wall portion) that connects the upper portion of the side wall 1202, and the building 12 is separated by the side wall 1202 and the roof 1204. The entire region and the entire upper region are closed.
In the building 12, a diesel engine 2A, a microphone 14 (FIG. 2), and a sound generating means 20 are accommodated.
The building 12 is provided with a first duct (flue) 28 that guides exhaust gas discharged from the diesel engine 2 </ b> A to the outside of the building 12.
That is, the side wall 1202 of the building 12 is provided with an exhaust port 30 communicating with the first duct 28, and the first very low frequency sound S 1 generated from the diesel engine 2 A passes through the first duct 28 and is exhausted. 30 is discharged to the outside of the building 12 toward the object 4.

The microphone 14 detects information related to the first very low frequency sound S1, and the information is the amplitude, frequency, and phase of the first very low frequency sound S1.
The signal processing unit 16 generates a signal having a phase opposite to that of the first very low frequency sound S <b> 1 based on information detected by the microphone 14. The signal processing unit 16 can be configured by a DSP (Digital Signal Processor).
The controller 18 drives the sound generation means 20 based on the signal supplied from the signal processing unit 16 to cancel the first very low frequency sound S1 and has the opposite phase to the first very low frequency sound S1. The second very low frequency sound S2 is generated from the sound generating means 20.
In the present embodiment, the signal processing unit 16 and the controller 18 constitute a control means.
The signal processing unit 16 and the controller 18 may be provided either outside or inside the building 12.

The sound generation means 20 generates an ultra-low frequency sound of 20 Hz or less as the second ultra-low frequency sound S2.
As such a sound generating means 20, for example, a commercially available product as shown in FIG. 3 can be used.
The subwoofer unit 22 has an appearance similar to that of a fan, and includes a motor 22B attached to a base 22A, a rotating body 22C, a plurality of rotating shafts 22D, a plurality of blades 22E, It is configured including a voice coil.
The rotating body 22C has a disk shape and is rotated around the central axis by the motor 22B.
The plurality of rotating shafts 22D are provided on the outer periphery of the rotating body 22C so as to protrude outward in the radial direction of the rotating body 22C at equal intervals in the circumferential direction. Each rotary shaft 22D is provided with the voice coil, and is configured to be rotated around the axis by the voice coil.
The plurality of blades 22E are attached to the respective rotation shafts 22D, and are configured such that the pitch of each blade 22E (an angle around the rotation shaft 22D of the blades 22E) is changed by the voice coil.
Each blade 22E of the electric fan becomes a variable pitch by driving each voice coil by a drive signal supplied from the controller 18 while the fan 22E of the electric fan is rotated at a constant speed by the motor 22B, and the pitch is changed. , Air molecules are moved, pressure waves are generated, and bass is output.

In the present embodiment, the sound generating means 20 is accommodated in the enclosure 26 installed inside the building 12 and installed on the gantry 24.
The enclosure 26 is formed with a radiation opening 2602 that radiates sound generated from the sound generation means 20, and the radiation opening 2602 communicates with an intermediate portion of the first duct 28 via the second duct 29. Has been.
Then, the sound generating means 20 includes a first ultra-low frequency sound in the middle of the second ultra-low frequency sound S2 from the diesel engine 2A to the object 4 via the radiation opening 2602 and the second duct 29. It arrange | positions so that it may face S1, and 2nd ultra low frequency sound S2 does not point the target object 4 and the diesel engine 2A.
By housing the sound generating means 20 in the enclosure 26, it is possible to suppress the sound radiated from the front of the sound generating means 20 from interfering with the sound radiated from the rear of the sound generating means 20, and further to the enclosure. The sound pressure of the second very low frequency sound S2 output by the resonance of 26 can be increased. Further, it is advantageous for easily securing a large-capacity enclosure 26. Therefore, it is more advantageous in securing the sound pressure of the second very low frequency sound S2 generated from the sound generating means 20.

FIG. 4 is a diagram comparing the output characteristics of the subwoofer unit 22 and the cone-type woofer used in the audio apparatus, where the horizontal axis represents frequency (Hz) and the vertical axis represents sound pressure level (dB SPL). Is shown.
In the figure, an output characteristic A indicated by a broken line indicates the subwoofer unit 22, and the remaining five output characteristics B to F indicate a commercially available cone type woofer.
A solid line G indicates a hearing threshold.
As is clear from FIG. 4, the subwoofer unit 22 outputs a substantially constant sound pressure over 1 Hz to 32 Hz, and has excellent output characteristics compared to other cone-type woofers.
Since the frequency of the first ultra-low frequency sound S1 is about 16 Hz, it is first to use the subwoofer unit 22 as the sound generating means 20 whose sound pressure near 16 Hz is larger than that of other cone type woofers. This is preferable for effectively canceling the very low frequency sound S1.

  Of course, other cone-type woofers or various conventionally known woofers can be used as the sound generating means 20 instead of the subwoofer unit 22. In this case, the controller 18 in FIG. Replace it.

Next, the function and effect of the ultra-low frequency sound reducing device 10A will be described.
5A to 5C are explanatory diagrams of the principle of canceling the very low frequency sound, where the horizontal axis indicates time and the vertical axis indicates sound amplitude.
When the diesel engine 2A is operated, as shown in FIG. 5A, the first ultra-low frequency sound S1 is generated.
The signal processing unit 16 and the controller 18 cancel the first very low frequency sound S1 based on the information about the first very low frequency sound S1 detected by the microphone 14 as shown in FIG. 5B. The sound generating means 20 generates a second very low frequency sound S2 having an opposite phase to the sufficient first very low frequency sound S1.
As a result, as shown in FIG. 5C, the first ultra-low frequency sound S1 generated from the diesel engine 2A and the second ultra-low frequency sound S2 generated from the sound generating means 20 cancel each other out with a broken line. As shown, very low frequency sound is reduced.
That is, since the second very low frequency sound S2 generated from the sound generating means 20 is directed to the first very low frequency sound S1 on the way from the diesel engine 2A to the object 4, the first generated from the diesel engine 2A. The ultra-low frequency sound is reduced by canceling out the first ultra-low frequency sound S1 and the second ultra-low frequency sound S2 generated from the sound generating means 20 at a location in front of the object 4.
Therefore, it is possible to effectively reduce the influence of the first ultra-low frequency sound S1 of the diesel engine 2A on the object 4 with a simple configuration.

  In addition, since it is not necessary to construct a large concrete sound insulation room, the space in the building 12 can be secured, and the ultra-low frequency sound reducing device 10A has a simple configuration, so the ultra-low frequency sound reducing device 10A. This is advantageous in reducing labor and cost when installing the device.

It is also conceivable to direct the second very low frequency sound S2 toward the object 4, but in this case, the phase of the second very low frequency sound S2 with respect to the phase of the first very low frequency sound S1 is accurate. If the phase does not become opposite, not only the cancellation of the first ultra-low frequency sound S1 and the second ultra-low frequency sound S2 is insufficient, but also the second ultra-low frequency with respect to the object 4 The wave sound S2 also has an effect.
On the other hand, in the present embodiment, since the second very low frequency sound S2 is not directed to the object 4, the first very low frequency sound S1 and the second very low frequency sound S2 are cancelled. Even if it becomes insufficient, the second ultra-low frequency sound S2 is difficult to propagate to the object 4, which is advantageous in suppressing the influence on the object 4.

In addition, also when the air compressor which generate | occur | produces 1st very low frequency sound S1 instead of the diesel engine 2A is provided as the installation 40, 10 A of ultra low frequency sound reduction apparatuses similar to 1st Embodiment are provided. By using this, the same effect is produced.
In this case, the air compressor is provided with a first duct 28 for guiding air from the outside of the building 12, and an air intake port communicating with the first duct 28 is provided instead of the exhaust port 30, and is generated from the air compressor. The first ultra-low frequency sound S1 that passes through the first duct 28 is directed to the object 4 from the intake port.

(Second Embodiment)
Next, a second embodiment will be described.
As shown in FIG. 6, the ultra-low frequency sound reducing device 10B of the second embodiment is provided with an equipment 26 as an ultra-low frequency sound source and an enclosure 26 that houses the sound generating means 20 installed outdoors. Is different from the first embodiment.
In the following embodiments, the same parts and members as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

In the present embodiment, the facility is a vibrating screen device 2B (classifier), and the vibrating screen device 2B vibrates the screen from the excavated mud generated by the muddy water type shield construction method. It separates water containing silt clay.
The vibration sieving device 2B operates to generate an ultra-low frequency sound of 16 Hz or less as the first ultra-low frequency sound S1, and the first ultra-low frequency sound S1 is emitted to outdoor air and travels toward the object 4. .

  The microphone 14 is installed at an appropriate location where the first ultra-low frequency sound S1 can be detected, and the signal processing unit 16 and the controller 18 are installed at an appropriate location near the enclosure 26, for example.

In the present embodiment, the sound generating means 20 is housed in the enclosure 26 installed at a location adjacent to the vibration sieving device 2B and installed on the gantry 24.
The enclosure 26 is formed with a radiating opening 2602 that radiates sound generated from the sound generating means 20, and the radiating opening 2602 opens upward.
The sound generating means 20 is arranged so that the second very low frequency sound S2 is directed to the first very low frequency sound S1 on the way from the vibration sieving device 2B to the object 4 through the radiation opening 2602. The second very low frequency sound S2 is not directed to the object 4 and the vibration sieving device 2B.
As in the first embodiment, accommodating the sound generating means 20 in the enclosure 26 is more advantageous in securing the sound pressure of the second ultra-low frequency sound S2.

Also in the second embodiment, the microphone 14, the signal processing unit 16, the controller 18, and the sound generating means 20 operate in the same manner as in the first embodiment, and the second generated from the sound generating means 20 is used. Since the very low frequency sound S2 is directed to the first very low frequency sound S1 on the way from the vibration sieving device 2B to the object 4, the first ultralow frequency sound S1 generated from the vibration sieving device 2B and sound generation are generated. The ultra-low frequency sound is reduced by canceling out the second ultra-low frequency sound S2 generated from the means 20 at a location in front of the object 4.
Therefore, it is possible to effectively reduce the influence of the first ultra-low frequency sound S1 of the vibration sieving device 2B on the object 44 with a simple configuration. Therefore, it is not necessary to construct a concrete sound insulation room as in the conventional case, so it is possible to reduce the labor and cost required for construction and dismantling, and to solve environmental problems such as noise and waste disposal during dismantling. This is advantageous.

  Similarly to the first embodiment, since the second ultra-low frequency sound S2 is not directed to the object 4, the first ultra-low frequency sound S1 and the second ultra-low frequency sound S2 are canceled out. Even if the alignment is insufficient, the second ultra-low frequency sound S2 is difficult to propagate to the object 4, which is advantageous in suppressing the influence on the object 4.

(Third embodiment)
Next, a third embodiment will be described.
As shown in FIG. 7, the ultra-low frequency sound reducing device 10C of the third embodiment directs the second ultra-low frequency sound S2 generated from the sound generating means 20 to the ultra-low frequency sound generation source. This is different from the first and second embodiments.

In the present embodiment, a case will be described in which the ultra-low frequency sound generation source is a vibrating conveyor 2 </ b> C as equipment installed inside the building 12.
Similarly to the first embodiment, the building 12 includes a side wall 1202 (wall portion) having sound insulation properties and a roof 1204 (wall portion) having sound insulation properties connecting the upper portions of the side walls 1202. The side wall 1202 and the roof 1204 block the entire side area and the entire upper area.
In the present embodiment, a building opening 1210 such as a ventilation louver or a window that penetrates the inside and outside of the building 12 is provided on the side wall 1202 of the building 12. Therefore, the first ultra-low frequency sound S <b> 1 generated from the vibration conveyor 2 </ b> C propagates through the space inside the building 12, is emitted from the building opening 1210 to the outside of the building 12, and travels toward the object 44.

In the present embodiment, the sound generating means 20 is accommodated in the enclosure 26 installed inside the building 12 and installed on the gantry 24.
The enclosure 26 is formed with a radiating opening 2602 for radiating sound generated from the sound generating means 20, and the sound generating means 20 vibrates the second ultra-low frequency sound S <b> 2 via the radiating opening 2602. It arrange | positions so that it may face the conveyor 2C, and the 2nd very low frequency sound S2 does not point the target object 4. FIG.
As in the first embodiment, accommodating the sound generating means 20 in the enclosure 26 is more advantageous in securing the sound pressure of the second ultra-low frequency sound S2.

Also in the third embodiment, the microphone 14, the signal processing unit 16, the controller 18, and the sound generation unit 20 operate in the same manner as in the first embodiment, and the second generated from the sound generation unit 20. Since the very low frequency sound S2 is directed to the first very low frequency sound S1 on the way from the vibrating conveyor 2C to the object 4, the first very low frequency sound S1 generated from the vibrating conveyor 2C and the sound generating means 20 are used. The ultra-low frequency sound is reduced by canceling out the second ultra-low frequency sound S2 generated from the above at a location near the vibrating conveyor 2C.
Therefore, it is possible to effectively reduce the influence of the first ultra-low frequency sound S1 of the vibrating conveyor 2C on the object 44 with a simple configuration.
Further, since it is not necessary to construct a large concrete sound insulation room, the space in the building 12 can be secured, and the ultra-low frequency sound reducing device 10C has a simple configuration, so the ultra-low frequency sound reducing device 10C. This is advantageous in reducing labor and cost when installing the device.

  Similarly to the first embodiment, since the second ultra-low frequency sound S2 is not directed to the object 4, the first ultra-low frequency sound S1 and the second ultra-low frequency sound S2 are canceled out. Even if the alignment is insufficient, the second ultra-low frequency sound S2 is difficult to propagate to the object 4, which is advantageous in suppressing the influence on the object 4.

  In the embodiment, the case where the ultra-low frequency sound generation source is the diesel engine 2A, the vibration sieve device 2B, the vibration conveyor 2C, and the air compressor has been described. It is not limited as long as it is a device or facility that generates ultra-low frequency sound.

  2A ... diesel engine, 2B ... vibrating sieve device, 2C ... vibrating conveyor, 4 ... object, 10A, 10B, 10C ... ultra-low frequency sound reducing device, 12 ... building, 1202 ... side wall (wall) Part), 1204 ... ceiling (wall part), 14 ... microphone (detection means), 16 ... signal processing part (control means), 18 ... controller (control means), 20 ... sound generation means, 26 ... ... enclosure, 2602 ... radiation opening, 28 ... first duct, 29 ... second duct.

Claims (8)

A method for reducing the influence of a first ultra-low frequency sound generated from an ultra-low frequency sound source on an object,
Providing sound generating means for generating a second ultra-low frequency sound;
The second ultra-low frequency sound generated from the sound generating means is not directed to the object and the ultra-low frequency sound generation source, and the midway from the ultra-low frequency sound generation source to the object Direct to the first very low frequency sound,
Detecting information about the first very low frequency sound;
As the second ultra-low frequency sound, the sound is generated as an ultra-low frequency sound having an opposite phase to the first ultra-low frequency sound, which is sufficient to cancel the first ultra-low frequency sound based on the detected information. Generated from the means,
An ultra-low frequency sound reduction method. A method for reducing the influence of a first ultra-low frequency sound generated from an ultra-low frequency sound source on an object,
Providing sound generating means for generating a second ultra-low frequency sound;
Directing the second very low frequency sound generated from the sound generating means to the very low frequency sound generation source without directing to the object;
Detecting information about the first very low frequency sound;
As the second ultra-low frequency sound, the sound is generated as an ultra-low frequency sound having an opposite phase to the first ultra-low frequency sound, which is sufficient to cancel the first ultra-low frequency sound based on the detected information. Generated from the means,
An ultra-low frequency sound reduction method. An ultra-low frequency sound reduction device that reduces the influence of a first ultra-low frequency sound generated from an ultra-low frequency sound source on an object,
Detecting means for detecting information relating to the first very low frequency sound generated from the very low frequency sound source;
Generating a second very low frequency sound, and directing the second very low frequency sound from the very low frequency sound source without directing the second very low frequency sound to the very low frequency sound source and the object; Sound generating means arranged to be directed to the first ultra-low frequency sound on the way to
As the second ultra-low frequency sound, the sound is generated as an ultra-low frequency sound having an opposite phase to the first ultra-low frequency sound, which is sufficient to cancel the first ultra-low frequency sound based on the detected information. Control means generated from the means;
An ultra-low frequency sound reduction device comprising: An ultra-low frequency sound reduction device that reduces the influence of a first ultra-low frequency sound generated from an ultra-low frequency sound source on an object,
Detecting means for detecting information relating to the first very low frequency sound generated from the very low frequency sound source;
Sound generating means arranged to generate a second ultra-low frequency sound and to direct the second ultra-low frequency sound to the ultra-low frequency sound generation source without directing to the object; ,
As the second ultra-low frequency sound, the sound is generated as an ultra-low frequency sound having an opposite phase to the first ultra-low frequency sound, which is sufficient to cancel the first ultra-low frequency sound based on the detected information. Control means generated from the means;
An ultra-low frequency sound reduction device comprising: A building was constructed in which the entire side area and the entire upper area were closed by the sound-insulating wall,
The ultra-low frequency sound generation source, the detection means and the sound generation means are housed in the building,
An enclosure in which an opening for radiation that contains the sound generating means and emits the second ultra-low frequency sound is formed is provided inside the building,
The ultra-low frequency sound reduction device according to claim 3 or 4, A building was constructed in which the entire side area and the entire upper area were closed by the sound-insulating wall,
The ultra-low frequency sound generation source, the detection means and the sound generation means are housed in the building,
A first duct is formed for guiding the first ultra-low frequency sound from the ultra-low frequency sound source to the outside of the building;
An enclosure in which an opening for radiation that contains the sound generating means and emits the second ultra-low frequency sound is formed is provided inside the building,
A second duct is formed which communicates the radiation opening and the middle of the first duct;
The ultra-low frequency sound reduction device according to claim 3. The ultra-low frequency sound generation source and the enclosure that houses the sound generation means are installed outdoors,
The ultra-low frequency sound reduction device according to claim 3 or 4, The ultra-low frequency sound source is a vibrating screen device that separates excavated soil generated by a shield method into water containing earth and sand and silt clay,
The ultra-low frequency sound reduction device according to any one of claims 3 to 7, wherein

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