JP6815165B2 - Active noise control system - Google Patents

Description

The present invention relates to an active noise control system that reduces noise at a control point by emitting a control sound.

Conventionally, as an active noise control system for reducing noise, those having various structures have been proposed (see, for example, Non-Patent Document 1 and Patent Document 1).

FIG. 4 is a block diagram showing an example of a conventional configuration of an active noise control system. Reference numeral 102 in the drawing indicates a first microphone arranged in the vicinity of the noise source J1 to detect the noise, and reference numeral 103 is a reference microphone. A second microphone for detecting a sound at an arbitrary position (control point) at which noise is desired to be reduced is indicated by reference numeral 105 for emitting a sound having a phase opposite to the noise detected by the first microphone 102 from the speaker 104. A control unit that generates a speaker drive signal based on the detection signals from the first microphone 102 and the second microphone 103 is shown, and reference numeral 107 indicates an amplifier that amplifies the speaker drive signal.

Further, FIG. 5 is a block diagram showing another example of the conventional configuration of the active noise control system, in which reference numeral 202 is arranged in the vicinity of the noise source J2 in the interior of the building to detect the noise. 1 microphone is indicated, reference numeral 203 indicates a second microphone arranged on the indoor side of the window opening 206 to detect sound, and reference numeral 205 indicates a sound having a phase opposite to the noise detected by the first microphone 202. A control unit that generates a speaker drive signal for emitting from 204 based on the detection signals from the first microphone 202 and the second microphone 203 is shown, and reference numeral 207 indicates an amplifier that amplifies the speaker drive signal. ..

Japanese Patent Application Laid-Open No. 8-314471

Homepage of IHI Rotating Machinery Co., Ltd., Active Noise Reduction System, [Search on September 7, 2016], Internet (URL: https://www.ihi.co.jp/inc/product/product01. html)

By the way, there are cases where it is desired to effectively reduce noise outside the building (for example, running noise of a car or train) inside the building, but a noise having an appropriate structure has not been proposed.

An object of the present invention is to provide an active noise control system capable of solving the above-mentioned problems.

The first aspect of the present invention is illustrated in FIG. 1A, in an active noise control system (1) that reduces noise at control points (CP1, CP2) by emitting a control sound.
An external microphone (2) that is placed outside the building (B) and detects noise outside the building (B),
An internal microphone unit (3) arranged at control points (CP1, CP2) inside the building (B) and detecting sound at the control points (CP1, CP2), and
A speaker arranged on the outdoor side (6o) of the window opening (6) and near the edge of the window opening (6) so as to emit a control sound along the window opening (6) of the building (B). Unit (4) and
The speaker drive signal (S5) for emitting a sound having a phase opposite to the noise detected by the external microphone (2) from the speaker unit (4) is based on the detection signal (S2) from the external microphone (2). A signal that is generated and optimizes the speaker drive signal (S5) based on the detection signal (S3) from the internal microphone unit (3) so that noise at the control points (CP1 and CP2) is reduced. Processing unit (5) and
With
The speaker drive signal (S5) from the signal processing unit (5) is configured to reduce noise at the control points (CP1 and CP2) by emitting a control sound from the speaker unit (4). It is a feature.

A second aspect of the present invention is that the speaker unit (4) is the outdoor side (6o) of the window opening (6) and is near the upper edge (6A) and / or the lower edge of the window opening (6). (6B) It is characterized in that it is arranged in the vicinity.

The third aspect of the present invention is illustrated in FIGS. 1 (a) and 2 (b), wherein the speaker unit (4) is the outdoor side (6o) of the window opening (6). ) To the first upper speaker (4A) arranged near the upper edge (6A) of the window opening (6) and to the first upper speaker (4A) along the upper edge (6A). It has at least a second upper speaker (4B) arranged side by side,
The internal microphone unit (3) is characterized by having at least a first internal microphone (3A) and a second internal microphone (3B).

The fourth aspect of the present invention is illustrated in FIGS. 1A and 1B, which is the outdoor side (6o) of the window opening (6) and the lower edge of the window opening (6). 6B) A first lower speaker (4C) arranged so as to face the first upper speaker (4A) in the vicinity, and the first lower speaker (4C) along the lower edge (6B). ), And a second lower speaker (4D) arranged so as to face the second upper speaker (4B).

A fifth aspect of the present invention is a concrete surface near the lower edge (6B) of the window opening (6) and facing the first upper speaker (4A) and the second upper speaker (4B). It is characterized in that (F) is formed.

A sixth aspect of the present invention is characterized in that the speaker unit (4) has a line array speaker.

It should be noted that the numbers in parentheses and the like are for convenience to indicate the corresponding elements in the drawings, and therefore, this description is not limited to the description on the drawings.

According to the first to sixth viewpoints described above, it is possible to reduce noise outside the building that invades from the window opening to the control point.

According to the third aspect described above, it is possible to expand the spatial area where noise can be reduced as compared with the case where there is only one microphone.

FIG. 1 (a) is a cross-sectional view showing an example of the configuration of the active noise control system according to the present invention, and FIG. 1 (b) is a view taken along the line DD. 2 (a) to 2 (c) are front views showing each example of the speaker arrangement state. FIG. 3 is a graph for explaining the effect of the present invention. FIG. 4 is a block diagram showing an example of a conventional configuration of an active noise control system. FIG. 5 is a block diagram showing another example of the conventional configuration of the active noise control system.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 3.

The active noise control system according to the present invention is configured to reduce noise at a control point by emitting a control sound in the vicinity of the control point (that is, any point at which noise is desired to be reduced). ..

The active noise control system according to the present invention is illustrated by reference numeral 1 in FIG. 1 (a).
-An external microphone (sensor microphone) 2 that is placed on the outside Bo of the building B and detects the noise of the outside Bo of the building B,
An internal microphone unit (control point microphone) 3 arranged at control points CP1 and CP2 of the internal Bi of the building B and having at least one internal microphone for detecting sound (noise) at the control points CP1 and CP2.
・ Speaker unit (control speaker unit) 4 and
A signal processing unit (control unit) 5 that generates a speaker drive signal S5 for emitting a control sound from the speaker unit 4 and
Is equipped with.

Further, the signal processing unit 5 described above generates a speaker drive signal S5 for emitting a sound having a phase opposite to the noise detected by the external microphone 2 from the speaker unit 4 based on the detection signal S2 from the external microphone 2. It is configured to generate. Further, the signal processing unit 5 has the internal microphone so that the noise at the control points CP1 and CP2 is reduced (preferably, the noise in the vicinity of the control points CP1 and CP2 is minimized). It is configured to optimize the speaker drive signal S5 based on the detection signal S3 from the unit 3. The speaker drive signal (that is, the drive signal optimized as described above) S5 from the signal processing unit 5 is amplified by the amplifier 7 to drive the speaker unit 4, and as a result, the speaker drive signal S5 causes the speaker unit 4. The speaker unit 4 emits a control sound, and the noise at the control points CP1 and CP2 is reduced.

By the way, the speaker unit 4 described above is the outdoor side 6o of the window opening 6 and is arranged near the edges 6A and 6B of the window opening 6. Specifically, the speaker unit may be arranged along the side edge of the window opening 6 as illustrated by reference numerals 4E, 4F, 4G, and 4H in FIG. 2A. It is preferable that the outdoor side 6o of the window opening 6 is arranged in the vicinity of the upper edge 6A and / or the lower edge 6B of the window opening 6. In other words
The first upper speaker 4A is arranged in the vicinity of the upper edge 6A of the window opening 6 on the outdoor side 6o of the window opening 6, and the second upper side is placed on the first upper speaker 4A along the upper edge 6A. Speakers 4B can be installed side by side,
-As illustrated by reference numerals 4C and 4D in FIG. 2C, the window opening 6 may be arranged near the lower edge 6B of the window opening 6.
As illustrated by reference numerals 4A, 4B, 4C, and 4D in FIG. 1B, the window openings 6 may be arranged near both the upper edge 6A and the lower edge 6B.
Then it is good. When the first upper speaker 4A and the second upper speaker 4B are provided as illustrated in FIG. 2B, the first upper speaker 4A and the second upper speaker 4A and the second upper speaker 4A are provided in the vicinity of the lower edge 6B of the window opening 6. A concrete surface F may be formed at a position facing the upper speaker 4B. Further, when the speaker unit is arranged in both the vicinity of the upper edge 6A and the vicinity of the lower edge 6B of the window opening 6, the speaker unit is as illustrated in FIG. 1 (b).
A first upper speaker 4A which is the outdoor side 6o of the window opening 6 and is arranged in the vicinity of the upper edge 6A of the window opening 6.
A second upper speaker 4B arranged in parallel with the first upper speaker 4A along the upper edge 6A, and
The first lower speaker 4C, which is the outdoor side 6o of the window opening 6 and is arranged so as to face the first upper speaker 4A in the vicinity of the lower edge 6B of the window opening 6.
A second lower speaker 4D arranged in parallel with the first lower speaker 4C along the lower edge 6B and arranged so as to face the second upper speaker 4B.
It is good to have at least.

The speaker unit described above does not emit a control sound toward the window opening 6 or a control sound in a direction away from the window opening 6, but emits a control sound along the window opening 6. Have been placed. In order to generate a control sound along the window opening 6, it is better to use a speaker having excellent directivity for the speaker unit 4, and specifically, it is preferable to use a line array speaker.

By the way, it is preferable that the above-mentioned internal microphone unit 3 is made into a stand type so as to be portable so that it can be freely moved inside the building B. For example, when reading on a sofa in the living room, the internal microphone unit 3 may be placed near the sofa (for example, on a table in front of the sofa). The internal microphone unit 3 may be connected to the signal processing unit 5 with a cord, or may be wirelessly connected. Further, it is preferable to use an omnidirectional microphone for the internal microphone unit 3. Further, the internal microphone unit 3 may have at least two first internal microphones 3A and two second internal microphones 3B, in which case the two microphones can be moved integrally. Either, or it may be possible to move them separately.

Further, in the example shown in FIG. 1A, the external microphone 2 is arranged on the handrail of the balcony, but of course, the present invention is not limited to this, and the external microphone 2 may be arranged at another position.

According to the present invention, it is possible to reduce the noise of the external Bo of the building B that invades from the window opening 6 to the control points CP1 and CP2. FIG. 3 is a graph for explaining the effect of the present invention, the broken line in the figure shows the measurement result of the sound pressure level when the active noise control is not performed in a certain dwelling unit, and the solid line in the figure is , The measurement result of the sound pressure level when active noise control is performed in the dwelling unit is shown. According to this experiment, it can be seen that the noise is reduced by about 10 dB in the sound range of the frequency of 100 to 250 Hz. In this experiment, the above-mentioned two microphones (first internal microphone 3A and second internal microphone 3B) and four speakers 4A, 4B, 4C, and 4D shown in FIG. 1 (b) were used.

Further, when the internal microphone unit 3 is composed of two microphones (first internal microphone 3A and second internal microphone 3B) as described above, the space area where noise can be reduced is expanded as compared with the case where there is only one microphone. Can be done. As a result of confirmation by the present inventors by experiments, it was found that noise can be reduced in a spatial region having a radius of 1 to 2 m.

Since it is difficult to reduce noise having a frequency higher than 300 Hz by the system of the present invention, such noise having a high frequency may be reduced by a known means such as a double sash.

1 Active noise control system 2 External microphone 3 Internal microphone unit 3A 1st internal microphone 3B 2nd internal microphone 4 Speaker unit 4A 1st upper speaker 4B 2nd upper speaker 4C 1st lower speaker 4D 2nd lower speaker 5 Signal processing Unit 6 Window opening 6A Upper edge of window opening 6B Lower edge of window opening 6o Outdoor B Building Bi Inside of building Bo Outside of building CP1, CP2 Control point S5 Speaker drive signal

Claims (4)

In an active noise control system that reduces noise at control points by emitting a control sound
An external microphone that is placed outside the building and detects noise outside the building,
An internal microphone unit that is placed at a control point inside the building and detects sound at the control point,
To emit該建product control sound along the window opening of a outdoor side of the window opening, in the form sandwiched between the upper edge of the arrangement ceiling beams and windows open to the outside the chamber, and an upper A speaker unit having an upper speaker, which is arranged in contact with the slab,
A speaker drive signal for emitting a sound having a phase opposite to the noise detected by the external microphone from the speaker unit is generated based on the detection signal from the external microphone, and the noise at the control point is reduced. A signal processing unit that optimizes the speaker drive signal based on the detection signal from the internal microphone unit, and
With
The speaker unit is a line array speaker.
The speaker drive signal from the signal processing unit is configured to reduce noise at the control point by emitting a control sound from the speaker unit along the window opening on the outdoor side.
An active noise control system that features. The internal microphone unit has at least a first internal microphone and a second internal microphone.
The active noise control system according to claim 1 . The speaker unit has a lower speaker which is located on the outdoor side of the window opening and is arranged so as to face the upper speaker in the vicinity of the lower edge of the window opening .
The active noise control system according to claim 1 . A concrete surface is formed near the lower edge of the window opening and faces the upper speaker , and the lower speaker is arranged on the concrete surface.
The active noise control system according to claim 3 .

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