JPH0954593A - Diffracted sound suppressing speaker system - Google Patents
Diffracted sound suppressing speaker systemInfo
- Publication number
- JPH0954593A JPH0954593A JP7242264A JP24226495A JPH0954593A JP H0954593 A JPH0954593 A JP H0954593A JP 7242264 A JP7242264 A JP 7242264A JP 24226495 A JP24226495 A JP 24226495A JP H0954593 A JPH0954593 A JP H0954593A
- Authority
- JP
- Japan
- Prior art keywords
- sound
- speaker
- diffracted
- wave
- speakers
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 230000005855 radiation Effects 0.000 claims abstract description 10
- 230000001629 suppression Effects 0.000 claims description 41
- 238000009413 insulation Methods 0.000 claims description 28
- 230000001902 propagating effect Effects 0.000 claims description 4
- 230000007423 decrease Effects 0.000 abstract description 2
- 230000002452 interceptive effect Effects 0.000 abstract 1
- 230000002250 progressing effect Effects 0.000 abstract 1
- 230000000644 propagated effect Effects 0.000 description 6
- 238000009792 diffusion process Methods 0.000 description 2
- 230000002238 attenuated effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000030279 gene silencing Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Building Environments (AREA)
- Exhaust Silencers (AREA)
- Obtaining Desirable Characteristics In Audible-Bandwidth Transducers (AREA)
- Soundproofing, Sound Blocking, And Sound Damping (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明は、遮音壁などの上端を
回折して裏側へ伝搬する音波に対して、スピーカから逆
位相、同音圧の音波を放射し、双方の音波を音波干渉さ
せることによって、回折波の音波伝搬エネルギーを消耗
させる回折音抑制スピーカシステムに関するものであ
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention radiates sound waves of opposite phase and same sound pressure to a sound wave propagating to the back side by diffracting the upper end of a sound insulation wall or the like, and causing both sound waves to interfere with each other. The present invention relates to a diffracted sound suppressing speaker system that consumes sound wave propagation energy of diffracted waves.
【０００２】[0002]
【従来の技術】従来より、遮音壁などの上端近傍に、騒
音源からの音波と逆位相、同音圧の音波を放射するスピ
ーカを配し、遮音壁などを回折する騒音と、スピーカ音
とを音波干渉させ、騒音の伝搬を抑制するスピーカシス
テムに用いられるスピーカとしては、 １．遮音壁上端近傍に設置され、スピーカ開口面が騒音
の進行方向に向けられたスピーカ。 ２．遮音壁上端近傍に設置され、スピーカ開口面が上向
きのスピーカ。 ３．遮音壁上端近傍騒音発生源側に設置され、スピーカ
開口面が遮音壁上端に向けられたスピーカ。 などが上げられる。2. Description of the Related Art Conventionally, a speaker which emits a sound wave having the same sound pressure and a phase opposite to that of a sound source from a noise source is arranged near the upper end of a sound insulating wall or the like, and the noise diffracting the sound insulating wall and the speaker sound are interfered with each other. The speaker used in the speaker system that suppresses the propagation of noise includes: A speaker installed near the top of the sound insulation wall with the speaker opening facing the direction of noise. 2. A speaker installed near the top of the sound insulation wall with the speaker opening facing up. 3. A speaker installed on the noise source side near the top of the sound insulation wall, with the speaker opening facing the top of the sound insulation wall. And so on.
【０００３】これらのスピーカは、いずれも騒音の音波
と逆位相、同音圧の音波を放射するように工夫されたも
のであり、遮音壁裏側へ騒音が伝搬しないように動作さ
せることを目的として設置されたものである。These speakers are all devised so as to emit sound waves having the same sound pressure and a phase opposite to the sound wave of noise, and are installed for the purpose of operating so that noise does not propagate to the back side of the sound insulation wall. It is a thing.
【０００４】[0004]
【発明が解決しようとする課題】以上のように、従来の
技術は、遮音壁などを回折する音波の波面の伝搬状態
と、遮音壁などの近傍に設置されたスピーカによって放
射される音波の波面の伝搬状態とが、必ずしも一致する
ような構成になっていないことが多いため、周波数帯域
幅の広い騒音、あるいは、特に広いエリアの消音を目的
とするような場合には、対応が難しい。As described above, according to the conventional technique, the propagation state of the wavefront of the sound wave diffracting the sound insulation wall and the propagation of the wavefront of the sound wave radiated by the speaker installed in the vicinity of the sound insulation wall. In many cases, the configuration does not always match the state, so that it is difficult to deal with noise with a wide frequency bandwidth, or particularly when silencing a wide area.
【０００５】また、複数個のスピーカを用いて広いエリ
アをコントロールしようとすると、隣り合うスピーカが
互いに影響し合って、消音機能に支障が生ずる場合もあ
る。Further, when a large area is controlled by using a plurality of speakers, adjacent speakers may affect each other, and the muffling function may be hindered.
【０００６】本発明が解決しようとする課題は、上述の
問題点に鑑み、遮音壁などを回折して伝搬される音波に
対して、回折点近傍より、回折波の回折点における音波
の波面の伝搬状態と、回折音抑制スピーカの音波放射口
より放射される音波の波面の伝搬状態との違いが、逆相
関係を有することを除いて、極力小さくなるような音波
を放射することによって、双方の音波が互いに音波干渉
し合う点において、位相誤差が少なく、干渉効率の高い
伝搬特性を有する音波を放射する実用的な回折音抑制ス
ピーカシステムを提供することを目的とする。In view of the above-mentioned problems, the problem to be solved by the present invention is to propagate the wavefront of the sound wave at the diffraction point of the diffracted wave from the vicinity of the diffraction point with respect to the sound wave diffracted and propagated by the sound insulation wall or the like. The difference between the state and the propagation state of the wave front of the sound wave radiated from the sound wave emission port of the diffractive sound suppression speaker has the opposite phase relationship, and by radiating the sound wave as small as possible, It is an object of the present invention to provide a practical diffracted sound suppression speaker system that emits sound waves having a propagation characteristic with a small phase error and a high interference efficiency in that the sound waves interfere with each other.
【０００７】[0007]
【課題を解決するための手段】遮音壁を回折して伝搬す
る音波と、スピーカより出力される音波との音波干渉に
よって、回折音の伝搬を抑制する回折音抑制スピーカシ
ステムにおいて、複数個のスピーカを、それぞれの音波
放射口の長径外側エッジが遮音壁上端エッジとなるよう
に並べて遮音壁を構成し、前記スピーカの音波放射口の
長径を前記スピーカによって放射される音波の最大周波
数の１／２波長を超えない大きさとし、前記スピーカの
音波放射口の短径を前記スピーカによって放射される音
波の最大周波数の約１／２０波長程度の大きさとし、前
記スピーカの音波放射開口面を回折波の進行方向へ向け
たものである。A diffracted sound suppression speaker system that suppresses propagation of diffracted sound by sound wave interference between a sound wave diffracting and propagating through a sound insulation wall and a sound wave output from the speaker. , The sound-insulating walls are arranged such that the outer edges of the respective sound-wave emitting ports become the upper edges of the sound-insulating walls, and the sound-insulating walls are configured such that the long-side diameter of the sound-emitting ports of the speaker exceeds 1/2 wavelength of the maximum frequency of the sound wave emitted by the speaker. The size of the sound wave emission port of the speaker is set to be about 1/20 wavelength of the maximum frequency of the sound wave emitted by the speaker, and the sound wave emission opening surface of the speaker is directed in the traveling direction of the diffracted wave. It is a thing.
【０００８】また、騒音などの音波発生源を遮蔽板で遮
蔽し、前記遮蔽板外周に上記回折音抑制スピーカを設置
して、騒音などの音波発生源からの音波が遮蔽板で影と
なる背後に到達しないエリアをつくるものである。Further, a sound wave source such as noise is shielded by a shield plate, and the diffracted sound suppressing speaker is installed on the outer periphery of the shield plate so that the sound wave from the sound wave source such as noise becomes a shadow on the shield plate. To create an area that does not reach.
【０００９】また、スピーカエンクロージャー外周に、
上記回折音抑制スピーカを設置することによって、スピ
ーカの自由な拡散を制限するものである。Further, on the outer periphery of the speaker enclosure,
By installing the above-mentioned diffracted sound suppressing speaker, the free diffusion of the speaker is limited.
【００１０】[0010]
【作用】遮音壁の上端を回折して伝搬する音波に対し
て、遮音壁の上端に並べられた複数個のスピーカから逆
位相、同音圧の音波を放射し、双方の音波を音波干渉さ
せる回折音抑制スピーカにおいて、各スピーカの音波放
射口の長径をスピーカによって放射される音波の最大周
波数の１／２波長を超えない大きさとして、各スピーカ
に同一の信号を加えると、各スピーカの音波放射開口面
を連ねた面と対向し、該開口面を連ねた面との距離が一
定の距離にある任意の面内の各点では、それぞれ、位相
回転のむらが少なく、同じ位相の点を連ねて構成された
ような、位相と振幅の安定した波面が得られる。[Function] With respect to the sound wave diffracting and propagating at the upper end of the sound insulation wall, a plurality of loudspeakers arranged at the upper end of the sound insulation wall emit sound waves of opposite phase and same sound pressure, and suppress both sound waves to interfere with each other. In a speaker, when the same signal is applied to each speaker with the major axis of the sound wave emission port of each speaker not exceeding 1/2 wavelength of the maximum frequency of the sound wave emitted by the speaker, the sound wave emission opening surface of each speaker At each point in an arbitrary plane that is opposed to the surface in which the aperture planes are connected and has a constant distance from the surface in which the aperture planes are connected, and the phase rotation unevenness is small, and the points having the same phase are connected in series. A wavefront with stable phase and amplitude can be obtained.
【００１１】また、スピーカの音波放射口の長径外側エ
ッジが、遮音壁上端の回折音の発生源となるように配置
し、スピーカの音波放射口の短径を、スピーカによって
放射される音波の最大周波数の約１／２０波長程度の大
きさとすると、回折音の素元波発生源となるエッジと、
回折音の素元波発生源に対応する回折音抑制スピーカの
音波の発生源となる音波放射口の短径の中心線との位置
の違いを、音波干渉における許容範囲内に抑えることが
できるため、回折音とスピーカ音との音波干渉の位相誤
差を低減できる。Further, the long-diameter outer edge of the sound wave emission port of the speaker is arranged so as to be a source of the diffracted sound at the upper end of the sound insulation wall, and the short diameter of the sound wave emission port of the speaker is set to the maximum frequency of the sound wave emitted by the speaker. If the size is about 1/20 wavelength, the edge that becomes the source wave of the diffracted sound,
The difference in position from the center line of the minor axis of the sound wave emission port that is the sound source of the diffractive sound suppression speaker corresponding to the source wave of the diffracted sound can be suppressed within the allowable range for sound wave interference. The phase error of the sound wave interference between the diffracted sound and the speaker sound can be reduced.
【００１２】遮音壁の上端に設置されるスピーカの音波
放射開口面の方向を、回折波の進行方向に向けて設置す
るとき、スピーカの音波放射開口面の方向と、遮音壁の
上端近傍を直進する直進波の進行方向との成す角をθと
するとき、θを小さくするにしたがって、回折音抑制ス
ピーカによってコントロールされる範囲は、直進波側に
広がり、θが大きくなるにしたがって、回折音抑制スピ
ーカによってコントロールされる範囲は、回折音側に傾
いて、コントロールされる範囲は狭くなる。When the speaker is installed at the upper end of the sound insulation wall so that the direction of the sound wave emission opening surface of the speaker is directed toward the traveling direction of the diffracted wave, the sound wave emission opening surface of the speaker and the straight line in the vicinity of the upper end of the sound insulation wall go straight. Assuming that the angle formed by the traveling direction of the wave is θ, the range controlled by the diffractive sound suppression speaker expands toward the rectilinear wave side as θ becomes smaller, and the range controlled by the diffractive sound suppression speaker increases as θ increases. The controlled range inclines toward the diffracted sound side, and the controlled range becomes narrow.
【００１３】上述のように構成された回折音抑制スピー
カを、遮蔽板外周に設置して遮蔽板で音波発生源を遮蔽
すると、音波発生源からの音波が遮蔽板で影となる背後
に到達しにくいエリアをつくることができる。When the diffracted sound suppressing speaker constructed as described above is installed on the outer periphery of the shield plate and the sound source is shielded by the shield plate, the sound wave from the sound source reaches behind the shadow plate. You can create difficult areas.
【００１４】また、同様に、上述の回折音抑制スピーカ
をスピーカエンクロージャー外周に設置すると、指向性
を有するスピーカが得られる。Similarly, when the above-mentioned diffracted sound suppressing speaker is installed on the outer circumference of the speaker enclosure, a speaker having directivity can be obtained.
【００１５】[0015]
実施例１ 本発明による、回折音抑制スピーカを、図１、図２
（Ａ）（Ｂ）によって説明する。図１は、本発明による
複数個の回折音抑制スピーカを、半無限遮音壁上端に並
べた実施例１を示す斜視図、図２（Ａ）は、図１におけ
る複数個の回折音抑制スピーカによる波面の同相波面を
示す平面図、図２（Ｂ）は、回折波の伝搬状態を示す立
面図である。１１、１２、１３、・・・は、第１、第
２、第３、・・・回折音抑制スピーカ、２は、半無限遮
音壁、３１、３２、３３、・・・は、第１、第２、第
３、・・・音波放射口の長径外側エッジ、４は、第１、
第２、第３、・・・回折音抑制スピーカ１１、１２、１
３、・・・の音波放射口の短径の中心を結ぶ中心線、５
は、同相波面、Ｓは、騒音源、θは、音波放射開口面の
方向と直進波の進行方向との成す角である。以下その動
作について説明する。Embodiment 1 A diffracted sound suppressing speaker according to the present invention is shown in FIGS.
This will be described with reference to (A) and (B). FIG. 1 is a perspective view showing a first embodiment in which a plurality of diffracted sound suppression speakers according to the present invention are arranged on the upper end of a semi-infinite sound insulation wall, and FIG. 2 (A) is a wavefront by the plurality of diffracted sound suppression speakers in FIG. 2B is a plan view showing the in-phase wavefront of FIG. 2B, and FIG. 2B is an elevation view showing the propagation state of the diffracted wave. ..., first, second, third, ... Diffraction sound suppression speakers, 2 a semi-infinite sound insulation wall, 31, 32, 33 ,. 2, 3, ... Longer-diameter outer edge of the sound wave emission port, 4 is the first,
Second, third, ... Diffraction sound suppression speakers 11, 12, 1
3, ... A center line connecting the centers of the short diameters of the sound wave emitting ports, 5
Is the in-phase wavefront, S is the noise source, and θ is the angle formed by the direction of the sound wave radiation aperture plane and the traveling direction of the rectilinear wave. The operation will be described below.
【００１６】半無限遮音壁２上端に並べられた複数個の
回折音抑制スピーカ１１、１２、１３、・・・の中から
隣り合う任意の２つの回折音抑制スピーカを第２、およ
び、第３の回折音抑制スピーカ１２、１３として、これ
らに同一の信号が加えられたときの、それぞれの回折音
抑制スピーカが他の回折音抑制スピーカによって与えら
れる影響について、図２（Ａ）によって説明する。第
２、および、第３の回折音抑制スピーカ１２、１３から
放射される音波の最大周波数をｆ０として、第２、およ
び、第３の回折音抑制スピーカ１２、１３の音波放射口
の長径を、放射される音波の最大周波数ｆ０の１／２波
長を超えない大きさとすることによって、第２、およ
び、第３の回折音抑制スピーカ１２、１３の音波放射開
口面を連ねた面と対向する任意の波面は、他の隣り合う
回折音抑制スピーカから放射される音波との干渉によっ
て位相回転が著しく乱されることのない、安定した同相
波面４が得られる。Any two adjacent diffracted sound suppression speakers among the plurality of diffracted sound suppression speakers 11, 12, 13, ... Arranged on the upper end of the semi-infinite sound insulation wall 2 are the second and third. As the diffracted sound suppression speakers 12 and 13, the effect of each diffracted sound suppression speaker exerted by another diffracted sound suppression speaker when the same signal is applied thereto will be described with reference to FIG. Letting f 0 be the maximum frequency of the sound waves radiated from the second and third diffracted sound suppression speakers 12 and 13, the major axis of the sound wave emission ports of the second and third diffracted sound suppression speakers 12 and 13 be set. By setting the size so as not to exceed 1/2 wavelength of the maximum frequency f 0 of the radiated sound wave, it is opposed to the surface connecting the sound wave radiation opening surfaces of the second and third diffractive sound suppression speakers 12 and 13. As for the arbitrary wavefront, a stable in-phase wavefront 4 is obtained in which the phase rotation is not significantly disturbed by the interference with the sound waves emitted from other adjacent diffracted sound suppression speakers.
【００１７】第２、および、第３の回折音抑制スピーカ
１２、１３から放射される音波の最大周波数がｆ０より
も小さい周波数の場合は、波長は最大周波数ｆ０の波長
よりも大きくなるから、２つの回折音抑制スピーカの音
波放射開口面を連ねた面と対向する任意の波面内では、
音波の最大周波数がｆ０のときよりも、それぞれ隣り合
う他の回折音抑制スピーカの波面による影響は、受けに
くくなるため、より安定した同相波面４が得られる。A second, and, if the maximum frequency of the sound waves radiated from the third diffracted sound suppression speakers 12 and 13 of the smaller frequency than f 0, because the wavelength is larger than the wavelength of the maximum frequency f 0 In an arbitrary wavefront opposite to the surface connecting the sound wave emission aperture surfaces of the two diffracted sound suppression speakers,
Compared with the case where the maximum frequency of the sound wave is f 0 , it is less affected by the wavefronts of the adjacent diffractive sound suppressing speakers, so that a more stable in-phase wavefront 4 is obtained.
【００１８】つぎに、半無限遮音壁２上端に並べられた
複数個の回折音抑制スピーカ１１、１２、１３、・・・
の中から任意の１つ、第２の回折音抑制スピーカ１２を
取り出して、第２回折音抑制スピーカ１２の音波放射口
の長径外側エッジ３２を回折する回折波と、第２回折音
抑制スピーカ１２の音波放射口から放射される音波との
立面的な動作について、図２（Ｂ）によって説明する。
第２回折音抑制スピーカ１２後方遠方より直進して伝搬
してきた音波は、第２回折音抑制スピーカ１２の音波放
射口の長径外側エッジ３２を回折して半無限遮音壁２で
影となる裏側へ放射状に広がる。このとき、回折音は、
第２回折音抑制スピーカ１２の音波放射口の長径外側エ
ッジ３２を回折音の素元波発生源として伝搬していく。
回折音を逆相の音波によって音波干渉させ、効率よく回
折音を抑制するためには、回折音と逆相の音波との位相
差を±１０°以内としたい。そこで、第２回折音抑制ス
ピーカ１２の音波放射口の短径を、第２回折音抑制スピ
ーカ１２によって放射される音波の最大周波数ｆ０の約
１／２０波長程度の大きさとすることによって、回折音
の素元波発生源となる第２回折音抑制スピーカ１２の音
波放射口の長径外側エッジ３２と、第２回折音抑制スピ
ーカ１２の音波の発生源となる音波放射口の短径の中心
線４の位置との違いから生ずる誤差を少なくするととも
に、スピーカ開口面積を必要以上に小さくすることによ
って生ずるスピーカ出力のロスを低減することができ
る。Next, a plurality of diffracted sound suppression speakers 11, 12, 13, ... Arranged on the upper end of the semi-infinite sound insulation wall 2.
Any one of the above, the second diffracted sound suppressing speaker 12 is taken out, and the diffracted wave diffracting the long diameter outer edge 32 of the sound wave emission port of the second diffracted sound suppressing speaker 12 and the second diffracted sound suppressing speaker 12 The elevational operation with respect to the sound wave radiated from the sound wave radiating port will be described with reference to FIG.
The sound waves that have propagated straight from a distance far behind the second diffractive sound suppression speaker 12 are diffracted at the long-diameter outer edge 32 of the sound wave emission port of the second diffractive sound suppression speaker 12 and are radiated to the back side that is shaded by the semi-infinite sound insulation wall 2. Spread to. At this time, the diffracted sound is
The long-diameter outer edge 32 of the sound wave emission port of the second diffracted sound suppressing speaker 12 propagates as a source wave generation source of diffracted sound.
In order to efficiently suppress the diffracted sound by causing the diffracted sound to interfere with the sound wave by the opposite phase sound wave, the phase difference between the diffracted sound and the opposite phase sound wave should be within ± 10 °. Therefore, by setting the minor diameter of the sound wave emission port of the second diffractive sound suppression speaker 12 to be about 1/20 wavelength of the maximum frequency f 0 of the sound wave radiated by the second diffractive sound suppression speaker 12, The long-diameter outer edge 32 of the sound wave emission port of the second diffractive sound suppression speaker 12 that is the source of the fundamental wave of sound, and the short diameter center line of the sound wave emission port that is the source of sound waves of the second diffractive sound suppression speaker 12. It is possible to reduce the error caused by the difference from the position of 4 and to reduce the loss of the speaker output caused by making the speaker opening area smaller than necessary.
【００１９】第２回折音抑制スピーカ１２の音波放射開
口面の方向を、回折波の進行方向に向けて設置すると
き、第２回折音抑制スピーカ１２の音波放射開口面の方
向と、遮音壁の上端近傍を直進する直進波の進行方向と
の成す角をθとするとき、θを小さくするにしたがっ
て、第２回折音抑制スピーカ１２によってコントロール
される範囲は、直進波側に広がり、θが大きくなるにし
たがって、第２回折音抑制スピーカ１２によってコント
ロールされる範囲は、回折音側に傾いて、コントロール
される範囲は狭くなる。When the direction of the sound wave radiation opening surface of the second diffracted sound suppression speaker 12 is set so as to face the traveling direction of the diffracted wave, the direction of the sound wave radiation opening surface of the second diffracted sound suppression speaker 12 and the upper end of the sound insulation wall. Assuming that the angle formed by the traveling direction of a straight traveling wave traveling in the vicinity is θ, the range controlled by the second diffracted sound suppressing speaker 12 expands toward the straight traveling wave and θ increases as θ decreases. Accordingly, the range controlled by the second diffracted sound suppressing speaker 12 is inclined toward the diffracted sound side, and the controlled range is narrowed.
【００２０】実施例２ 図３に基づいて実施例２を説明する。図１、図２、と共
通の部分は、同一符号を付してある。６は、遮蔽板であ
る。図３は、本発明による実施例２を示すものであり、
複数個の第１、第２、第３、・・・回折音抑制スピーカ
１１、１２、１３、・・・を、遮蔽板６の外周に設置し
て、放射状に拡散される騒音源Ｓからの音波が、遮蔽板
６で影となる背後に回り込みにくいエリアをつくるもの
である。Second Embodiment A second embodiment will be described with reference to FIG. The same parts as those in FIGS. 1 and 2 are designated by the same reference numerals. 6 is a shielding plate. FIG. 3 shows a second embodiment according to the present invention,
A plurality of first, second, third, ... Diffraction sound suppression speakers 11, 12, 13 ,. This creates an area where the sound wave is less likely to wrap around behind the shielding plate 6 in the shadow.
【００２１】実施例３ 図４に基づいて実施例３を説明する。図１〜３と共通の
部分は、同一符号を付してある。７は、警報音発生源、
８は、緊急自動車である。図４は、本発明による実施例
３を示すものであり、複数個の第１、第２、第３、・・
・回折音抑制スピーカ１１、１２、１３、・・・を、遮
蔽板６の外周に、直進波と回折波との境界の音波の進行
方向と、回折音抑制スピーカの音波放射開口面の方向と
の成す角θが、適度な大きさを有するような方向に向け
て設置して、放射状に拡散される警報音発生源７からの
音波が、遮蔽板６で影となる緊急自動車８の車室内に過
大な音量で入り込まないようにするとともに、車外の広
い範囲に拡散される警報音の音量が、低減してしまうこ
とのないようにするものである。Third Embodiment A third embodiment will be described with reference to FIG. The same parts as those in FIGS. 1 to 3 are designated by the same reference numerals. 7 is an alarm sound source,
8 is an emergency car. FIG. 4 shows a third embodiment according to the present invention, in which a plurality of first, second, third, ...
The diffracted sound suppression speakers 11, 12, 13, ... Are provided on the outer periphery of the shield plate 6 along the traveling direction of the sound wave at the boundary between the rectilinear wave and the diffracted wave, and the direction of the sound wave radiation opening surface of the diffracted sound suppression speaker. The angle θ formed by is oriented so that it has an appropriate size, and the sound waves from the alarm sound source 7 that are radially diffused are shaded by the shielding plate 6 in the interior of the emergency vehicle 8. The volume of the warning sound diffused in a wide range outside the vehicle is prevented from being reduced, while preventing the sound from entering into the vehicle at an excessive volume.
【００２２】実施例４ 図５に基づいて実施例４を説明する。図１〜４と共通の
部分は、同一符号を付してある。９は、スピーカ、１０
は、スピーカエンクロージャーである。図５は、本発明
による実施例４を示すものであり、複数個の第１、第
２、第３、・・・回折音抑制スピーカ１１、１２、１
３、・・・を、スピーカエンクロージャー１０の左右側
面に、直進波と回折波との境界の音波の進行方向と、回
折音抑制スピーカの音波放射開口面の方向との成す角θ
が、適度な大きさを有するような方向に向けて設置し
て、スピーカ９からの音波がスピーカエンクロージャー
１０左右側面エッジ３１、３２、３３、・・・を回折し
て伝搬される回折波のエネルギーを、音波干渉によって
減衰させ、スピーカ９の音波の自由な拡散を制限するこ
とによって、スピーカに指向性を与えるものである。Fourth Embodiment A fourth embodiment will be described with reference to FIG. The same parts as those in FIGS. 1 to 4 are designated by the same reference numerals. 9 is a speaker, 10
Is a speaker enclosure. FIG. 5 shows Embodiment 4 according to the present invention, in which a plurality of first, second, third, ...
, ... on the left and right side surfaces of the speaker enclosure 10, an angle θ formed between the traveling direction of the sound wave at the boundary between the rectilinear wave and the diffracted wave and the direction of the sound wave emission opening surface of the diffracted sound suppression speaker.
However, the energy of the diffracted wave propagated by the sound wave from the speaker 9 diffracting the right and left side edges 31, 32, 33, ... Is attenuated by the sound wave interference and the free diffusion of the sound wave of the speaker 9 is limited, thereby giving the speaker directivity.
【００２３】[0023]
【発明の効果】本発明によれば、遮音壁によって音源が
影となり、音源から放射された音波が回折して伝搬され
るエリアをつくり、回折波の波面の伝搬状態が、遮音壁
上端エッジを素元波発生源として放射状に拡散する一様
な特性を有する波面となるようにコントロールし、回折
点近傍の回折音抑制スピーカより、放射状に拡散する回
折波に対して、回折波の波面の伝搬状態と逆位相、同音
圧の音波を放射し、双方の音波を音波干渉させることに
よって、回折波の伝搬エネルギーを効率よく低減するこ
とができる。According to the present invention, the sound source is shaded by the sound insulation wall to create an area where the sound wave radiated from the sound source is diffracted and propagated, and the propagation state of the wave front of the diffracted wave is based on the sound insulation wall upper edge. As a wave generation source, control is performed so that the wavefront has a uniform characteristic that diffuses radially, and the diffracted wave suppressing state near the diffraction point causes the propagation state of the wavefront of the diffracted wave with respect to the diffracted wave that diffuses radially. The propagation energy of the diffracted wave can be efficiently reduced by radiating sound waves having opposite phases and the same sound pressure and causing both sound waves to interfere with each other.
【００２４】従って、本発明による回折音抑制スピーカ
システムは、遮音壁を適宜に設定することによって、遮
音壁で影となる裏側に回折する音波を効果的に低減でき
るため、遮音壁の裏側へ伝搬する騒音の低減、遮蔽板で
遮蔽して影となるエリアに伝搬される騒音の低減、緊急
自動車の警報音の車室内への侵入の抑制、指向性を有す
るスピーカなどに利用することができる。また、本発明
による回折音抑制スピーカシステムは、空中の音波ばか
りでなく、水中などの音波についても、空中と同様に取
り扱うことができることは言うまでもない。Therefore, in the speaker system for suppressing diffracted sound according to the present invention, by appropriately setting the sound insulation wall, the sound waves diffracted to the back side shadowed by the sound insulation wall can be effectively reduced, so that the noise propagated to the back side of the sound insulation wall can be reduced. The present invention can be used for a reduction, a reduction in noise propagated to a shadowed area that is shielded by a shielding plate, a suppression of an alarm sound of an emergency vehicle from entering the vehicle interior, a speaker having directivity, and the like. Further, it goes without saying that the diffracted sound suppressing speaker system according to the present invention can handle not only sound waves in the air but also sound waves in the water in the same manner as in the air.
【図１】実施例１を示す斜視図である。FIG. 1 is a perspective view showing a first embodiment.
【図２】（Ａ）同相波面を示す平面図である。 （Ｂ）回折波の伝搬状態を示す立面図である。FIG. 2A is a plan view showing an in-phase wavefront. (B) An elevation view showing a propagation state of a diffracted wave.
【図３】実施例２を示す斜視図である。FIG. 3 is a perspective view showing a second embodiment.
【図４】実施例３を示す斜視図である。FIG. 4 is a perspective view showing a third embodiment.
【図５】実施例４を示す斜視図である。FIG. 5 is a perspective view showing a fourth embodiment.
１１、１２、１３、・・・ 第１、第２、第３、・・・
回折音抑制スピーカ ２ 半無限遮音壁 ３１、３２、３３、・・・ 第１、第２、第３、・・・
音波放射口の長径外側エッジ ４ 音波放射口の短径の中心線 ５ 同相波面 ６ 遮蔽板 ７ 警報音発生源 ８ 緊急自動車 ９ スピーカ １０ スピーカエンクロージャー Ｓ 音源 θ 音波放射開口面の方向と直進波進行方向との成す角11, 12, 13, ... First, second, third, ...
Diffraction sound suppression speaker 2 Semi-infinite sound insulation walls 31, 32, 33, ... First, second, third, ...
Edge of major axis of sound wave emission port 4 Center line of minor axis of sound wave emission port 5 In-phase wave front 6 Shield 7 Alarm sound source 8 Emergency vehicle 9 Speaker 10 Speaker enclosure S Sound source θ Direction of sound wave emission surface and traveling direction of straight wave Angle between
Claims (3)
ーカより出力される音波との音波干渉によって、回折音
の伝搬を抑制する回折音抑制スピーカシステムにおい
て、複数個のスピーカを、それぞれの音波放射口の長径
外側エッジが遮音壁上端エッジとなるように並べて遮音
壁を構成し、前記スピーカの音波放射口の長径を前記ス
ピーカによって放射される音波の最大周波数の１／２波
長を超えない大きさとし、前記スピーカの音波放射口の
短径を前記スピーカによって放射される音波の最大周波
数の約１／２０波長程度の大きさとし、前記スピーカの
音波放射開口面を回折波の進行方向へ向けたことを特徴
とする回折音抑制スピーカシステム。1. A diffracted sound suppression speaker system that suppresses the propagation of diffracted sound by sound wave interference between a sound wave diffracting and propagating through a sound insulation wall and a sound wave output from the speaker. The sound insulating wall is formed by arranging the long-diameter outer edges of the radiation ports to be the sound-insulating wall upper end edges, and the long diameter of the sound wave radiation port of the speaker is set to a size that does not exceed 1/2 wavelength of the maximum frequency of the sound waves radiated by the speaker. The short diameter of the sound wave emission port of the speaker is set to about 1/20 wavelength of the maximum frequency of the sound wave emitted by the speaker, and the sound wave emission opening surface of the speaker is directed in the traveling direction of the diffracted wave. A speaker system that suppresses diffracted sound.
板外周に上記回折音抑制スピーカを設置したことを特徴
とする請求項１記載の回折音抑制スピーカシステム。2. The diffractive sound suppression speaker system according to claim 1, wherein the sound wave source is shielded by a shielding plate, and the diffractive sound suppression speaker is installed on the outer periphery of the shielding plate.
折音抑制スピーカを設置したことを特徴とする請求項１
記載の回折音抑制スピーカシステム。3. The diffracted sound suppression speaker is installed on the outer circumference of a speaker enclosure.
The diffracted sound suppression speaker system described.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24226495A JP3937465B2 (en) | 1995-08-17 | 1995-08-17 | Diffraction sound suppression speaker system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24226495A JP3937465B2 (en) | 1995-08-17 | 1995-08-17 | Diffraction sound suppression speaker system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0954593A true JPH0954593A (en) | 1997-02-25 |
| JP3937465B2 JP3937465B2 (en) | 2007-06-27 |
Family
ID=17086684
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP24226495A Expired - Fee Related JP3937465B2 (en) | 1995-08-17 | 1995-08-17 | Diffraction sound suppression speaker system |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3937465B2 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001172925A (en) * | 1999-10-08 | 2001-06-26 | Mitsubishi Heavy Ind Ltd | Active sound insulation wall and active sound insulation unit |
| EP1349143A3 (en) * | 2002-03-29 | 2004-09-15 | Kabushiki Kaisha Toshiba | Active sound muffler and active sound muffling method |
| US7492911B2 (en) | 2003-05-15 | 2009-02-17 | Takenaka Corporation | Noise reducing device |
| CN117098052A (en) * | 2023-03-17 | 2023-11-21 | 锐捷网络股份有限公司 | a public address system |
-
1995
- 1995-08-17 JP JP24226495A patent/JP3937465B2/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001172925A (en) * | 1999-10-08 | 2001-06-26 | Mitsubishi Heavy Ind Ltd | Active sound insulation wall and active sound insulation unit |
| EP1349143A3 (en) * | 2002-03-29 | 2004-09-15 | Kabushiki Kaisha Toshiba | Active sound muffler and active sound muffling method |
| US7352870B2 (en) | 2002-03-29 | 2008-04-01 | Kabushiki Kaisha Toshiba | Active sound muffler and active sound muffling method |
| US7492911B2 (en) | 2003-05-15 | 2009-02-17 | Takenaka Corporation | Noise reducing device |
| CN117098052A (en) * | 2023-03-17 | 2023-11-21 | 锐捷网络股份有限公司 | a public address system |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3937465B2 (en) | 2007-06-27 |
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