JPH10260168A - Reverberation-type measuring device for sound absorption effectiveness - Google Patents
Reverberation-type measuring device for sound absorption effectivenessInfo
- Publication number
- JPH10260168A JPH10260168A JP9068094A JP6809497A JPH10260168A JP H10260168 A JPH10260168 A JP H10260168A JP 9068094 A JP9068094 A JP 9068094A JP 6809497 A JP6809497 A JP 6809497A JP H10260168 A JPH10260168 A JP H10260168A
- Authority
- JP
- Japan
- Prior art keywords
- sound
- reverberation
- sound absorbing
- leak hole
- absorbing material
- 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
Landscapes
- Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
- Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】この発明は車両や一般建築物
等に採用される各種の吸音材の吸音効果を測定する残響
式吸音効果測定装置に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reverberation type sound absorbing effect measuring device for measuring the sound absorbing effect of various sound absorbing materials used for vehicles, general buildings and the like.
【０００２】[0002]
【従来の技術】従来、例えば、自動車用吸音材の吸音効
果を測定する残響室式吸音効果測定装置は、図５（ａ）
にて示すごとく、密閉状の残響室１を備えており、この
残響室１内には、その底壁１ａ上にて、スピーカ２が残
響室１の周壁に向け音を発するように配置されている。
また、複数のマイクロフォン３が、残響室１内にて、底
壁１ａ上に配置した吸音材４の上方に配設されている。2. Description of the Related Art Conventionally, for example, a reverberation room type sound absorbing effect measuring apparatus for measuring a sound absorbing effect of a sound absorbing material for an automobile is shown in FIG.
As shown in FIG. 1, a closed reverberation chamber 1 is provided. Inside the reverberation chamber 1, a speaker 2 is arranged on its bottom wall 1a so as to emit sound toward the peripheral wall of the reverberation chamber 1. I have.
In addition, a plurality of microphones 3 are arranged in the reverberation room 1 above the sound absorbing material 4 arranged on the bottom wall 1a.
【０００３】そして、スピーカ２が、信号発生器５から
ノイズ信号を受けて音を発すると、この音は、残響室１
内にてランダムに反射されて吸音材４に入射する。この
ことは、スピーカ２が、残響室１内で均一な拡散的音場
を形成して吸音材４に音を入射させることを意味する。
このような音場の形成後、スピーカ２をオフ（図５
（ｂ）にて符号Ｐにより示す時間参照）すると、吸音材
４が、その吸音効果に基づき、残響室１内の音を時間Ｔ
の経過に伴い徐々に吸収する。換言すれば、残響室１内
の音が時間Ｔの経過に伴い徐々に減衰する（図５（ｂ）
にて符号Ｌにて示す特性参照）。When the speaker 2 receives a noise signal from the signal generator 5 and emits a sound, the sound is transmitted to the reverberation room 1.
The light is randomly reflected inside and enters the sound absorbing material 4. This means that the speaker 2 forms a uniform diffused sound field in the reverberation chamber 1 and causes sound to be incident on the sound absorbing material 4.
After such a sound field is formed, the speaker 2 is turned off (FIG. 5).
(Refer to the time indicated by the symbol P in (b).) When the sound absorbing material 4 changes the sound in the reverberation room 1 for a time T based on the sound absorbing effect.
Absorbs gradually over time. In other words, the sound in the reverberation room 1 gradually attenuates as the time T elapses (FIG. 5B).
, Refer to the characteristic indicated by L).
【０００４】そこで、このような減衰に伴う残響音の残
響時間を計測し、この計測結果から吸音材４の吸音率を
求める。なお、図５（ｂ）にて、符号Ｌ１は、残響室１
内に吸音材４がない場合に特性を示す。[0004] Therefore, the reverberation time of the reverberation sound accompanying such attenuation is measured, and the sound absorption coefficient of the sound absorbing material 4 is obtained from the measurement result. In FIG. 5B, reference symbol L1 denotes a reverberation room 1
The characteristics are shown when there is no sound absorbing material 4 inside.
【０００５】[0005]
【発明が解決しようとする課題】ところで、このような
吸音効果測定装置による場合、測定された吸音材の吸音
効果は、当該吸音材を自動車に設置したときの吸音効果
とよく対応している。しかしながら、吸音効果測定装置
の一壁の辺の長さが、例えば、３．３ｍｍと長いことか
ら、吸音効果測定装置の外形形状が大きく、当該吸音効
果測定装置の設置費用が膨大となるという不具合があ
る。By the way, in the case of such a sound absorbing effect measuring device, the measured sound absorbing effect of the sound absorbing material corresponds well to the sound absorbing effect when the sound absorbing material is installed in an automobile. However, since the length of one side of the wall of the sound absorbing effect measuring device is, for example, 3.3 mm, the external shape of the sound absorbing effect measuring device is large, and the installation cost of the sound absorbing effect measuring device becomes enormous. There is.
【０００６】このため、残響室１を小型化したいという
ニーズがでてくるわけであるが、この小型化に伴い、残
響室１内の音場が均一な拡散的音場でなくなってくる。
従って、残響室１内の残響音が徐々に減衰していく時間
から吸音効果を求める方法では、吸音効果が音の測定個
所によって変動する。よって、例えば１５点以上の多数
の測定点の平均値を利用して吸音効果を求める必要が生
じ、複雑な測定方法となってしまう。For this reason, there is a need to reduce the size of the reverberation room 1. However, as the size of the reverberation room 1 decreases, the sound field in the reverberation room 1 does not become a uniform diffuse sound field.
Therefore, in the method of obtaining the sound absorbing effect from the time when the reverberation sound in the reverberation room 1 gradually decreases, the sound absorbing effect varies depending on the measurement point of the sound. Therefore, for example, it is necessary to determine the sound absorbing effect by using the average value of a large number of measurement points of 15 or more points, which results in a complicated measurement method.
【０００７】これに対し、本発明者等は、残響室の小型
化及び測定方法の簡単化の双方を達成するため、残響室
式吸音効果測定装置について種々の検討を加えてみた。
その結果、非平行な外壁を有するとともに周壁の一部に
音の漏れ孔部を形成してなる残響室を準備し、残響室か
ら漏れ孔部を通り漏出する音を測定することで、残響室
の小型化を確保しつつ、従来の残響室式吸音効果測定装
置と同等以上の測定結果を得ることができるという結論
に到った。On the other hand, the present inventors have made various studies on a reverberation room type sound absorption effect measuring apparatus in order to achieve both miniaturization of the reverberation room and simplification of the measuring method.
As a result, a reverberation room having a non-parallel outer wall and a sound leak hole formed in a part of the peripheral wall is prepared, and the sound leaking from the reverberation room through the leak hole is measured. It has been concluded that it is possible to obtain a measurement result equal to or more than that of a conventional reverberation room type sound absorption effect measuring device while ensuring miniaturization of the device.
【０００８】このことは、残響室内の多数の測定点の平
均値に近い値が漏れ孔部の１カ所だけの測定で得られ、
従来の残響室式吸音効果測定装置の測定性能を少なくと
も維持しつつ、残響室の小型化と測定方法の簡単化を達
成できることを意味する。そこで、本発明は、以上のよ
うなことに着目して、非平行な壁を有する残響室の形状
を有効に活用して、小型化と良好な測定性能とを確保す
るようにした残響式吸音効果測定装置を提供することを
目的とする。[0008] This means that a value close to the average value of many measurement points in the reverberation chamber can be obtained by measuring only one location of the leak hole,
This means that downsizing of the reverberation room and simplification of the measurement method can be achieved while at least maintaining the measurement performance of the conventional reverberation room type sound absorption effect measuring device. Therefore, the present invention focuses on the above, and makes effective use of the shape of a reverberation chamber having non-parallel walls, thereby ensuring miniaturization and good measurement performance. An object of the present invention is to provide an effect measuring device.
【０００９】[0009]
【課題を解決するための手段】上記課題の解決にあた
り、請求項１乃至４に記載の発明によれば、残響室が非
平行な複数の壁からなるとともに、これら複数の壁の一
部には、漏れ孔部を形成されている。また、ランダム音
発生手段が、複数の壁の他の部分に設けたスピーカを備
え、このスピーカから残響室内にランダム音を発し残響
室内に非平行な壁形状のもと平均的音圧レベルの音場を
形成する。According to the present invention, the reverberation chamber comprises a plurality of non-parallel walls, and a part of the plurality of walls is provided. , A leak hole is formed. Further, the random sound generating means includes a speaker provided in another portion of the plurality of walls, and the speaker emits a random sound into the reverberation room, and a sound having an average sound pressure level under the non-parallel wall shape in the reverberation room. Form a place.
【００１０】そして、マイクロフォンが残響室内に吸音
材を配置した状態で漏れ孔部から漏出する音を検出する
と、この検出出力に基づき吸音材の吸音効果を測定す
る。これにより、残響室を約１ｍ四方以内の形状に小型
化しても、従来の残響式吸音効果測定装置の場合と同等
以上の良好な吸音効果特性を測定できる。また、残響室
の非平行な壁形状のもとでは、漏れ孔部の漏れ音圧レベ
ルが残響室内の内部音圧レベル平均値によく一致するこ
とから、残響室の漏れ孔部という一か所から漏出する音
圧レベルを測定するという簡単な測定でもって、残響室
内の多点計測データの平均値と同様の値が得られる。When the microphone detects the sound leaking from the leak hole with the sound absorbing material disposed in the reverberation chamber, the sound absorbing effect of the sound absorbing material is measured based on the detected output. Thereby, even if the reverberation chamber is reduced in size to about 1 m square or less, good sound absorption effect characteristics equal to or better than those of the conventional reverberation type sound absorption effect measurement device can be measured. Also, under the non-parallel wall shape of the reverberation room, the leak sound pressure level in the leak hole well matches the average value of the internal sound pressure level in the reverberation room. With the simple measurement of measuring the sound pressure level leaking from the reverberation chamber, a value similar to the average value of the multipoint measurement data in the reverberation chamber can be obtained.
【００１１】これにより、残響室の小型化及び低廉化並
びに測定方法の簡単化を確保しつつ従来の残響式吸音効
果測定装置による測定結果と同等以上の良好な値にて吸
音効果を測定できる。また、請求項２に記載の発明によ
れば、漏れ孔部が、残響室内の音が均一に吸音材の表面
に入るようにスピーカから遠く離れて位置する。Thus, the sound absorbing effect can be measured with a good value equal to or better than the result measured by the conventional reverberation type sound absorbing effect measuring device, while miniaturizing and reducing the cost of the reverberating room and simplifying the measuring method. According to the second aspect of the present invention, the leak hole is located far away from the speaker so that the sound in the reverberation chamber uniformly enters the surface of the sound absorbing material.
【００１２】これにより、吸音材の全体に亘る平均的な
吸音効果を良好に測定できる。また、請求項４に記載の
発明によれば、漏れ孔部が、複数の壁のうち最も面積の
小さい壁に形成されている。これにより、残響室内の音
の反射波を漏れ孔部にて最も多く獲得できる。その結
果、残響室内の音量を最も有効に活用できる。Thus, the average sound absorbing effect over the entire sound absorbing material can be measured well. According to the fourth aspect of the present invention, the leak hole is formed in the wall having the smallest area among the plurality of walls. Thereby, the most reflected waves of the sound in the reverberation chamber can be obtained at the leak hole. As a result, the volume in the reverberation room can be used most effectively.
【００１３】[0013]
【発明の実施の形態】以下、本発明の一実施形態を図面
により説明する。図１は、自動車用吸音材の吸音効果を
測定するに適した本発明に係る残響式吸音効果測定装置
の一例を示している。この吸音効果測定装置は、残響室
１０を備えている。この残響室１０は、小型の残響箱か
らなるもので、この残響室１０は、５角形状の底壁１１
と、この底壁１１に対向する５角形状の上壁１２と、こ
れら底壁１１と上壁１２との間に形成した周壁１３とに
より構成されている。周壁１３は、底壁１１及び上壁１
２の５角形状に対応して、５つの側壁１３ａ乃至１３ｅ
により構成されている。DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of a reverberation type sound absorbing effect measuring apparatus according to the present invention suitable for measuring the sound absorbing effect of a sound absorbing material for an automobile. This sound absorbing effect measuring device includes a reverberation room 10. The reverberation room 10 is composed of a small reverberation box, and the reverberation room 10 has a pentagonal bottom wall 11.
And a pentagonal upper wall 12 facing the bottom wall 11, and a peripheral wall 13 formed between the bottom wall 11 and the upper wall 12. The peripheral wall 13 includes a bottom wall 11 and an upper wall 1.
5, five side walls 13a to 13e corresponding to the two pentagonal shapes.
It consists of.
【００１４】ここで、残響室１０の底壁１１、上壁１２
及び各側壁１３ａ乃至１３ｅの各辺の長さは、図１にて
示すような寸法を有している。このため、残響室１０の
外形寸法は１（ｍ3 ）内に収まっている。また、残響室
１０の底壁１１、上壁１２及び各側壁１３ａ乃至１３ｅ
は互いに非平行となっている。これにより、残響室１０
の小型化のもとこの残響室１０内でランダム音を安定的
に確保できるようになっている。なお、残響室１０の各
壁は、滑らかな表面を有する鉄筋モルタル製のものであ
って、例えば４０（ｍｍ）の板厚を有する。Here, the bottom wall 11 and the upper wall 12 of the reverberation room 10
The length of each side of each of the side walls 13a to 13e has a dimension as shown in FIG. For this reason, the external dimensions of the reverberation room 10 are within 1 (m 3 ). Further, the bottom wall 11, the upper wall 12, and the side walls 13a to 13e of the reverberation chamber 10 are provided.
Are non-parallel to each other. Thereby, the reverberation room 10
As a result, random sounds can be stably secured in the reverberation room 10 under the miniaturization of the above. Each wall of the reverberation room 10 is made of reinforced mortar having a smooth surface, and has a plate thickness of, for example, 40 (mm).
【００１５】また、残響室１０の側壁１３ａの下部に
は、漏れ孔部１３ｆが円形状に形成されており、この漏
れ孔部１３ｆは、残響室１０内の音を外部に漏出させる
役割を果たす。また、本実施形態では、この漏れ孔部１
３ｆの内径ｄは、約７０（ｍｍ）となっている。ここ
で、漏れ孔部１３ｆの内径ｄを上述のように定めた根拠
について説明する。A leak hole 13f is formed in a circular shape below the side wall 13a of the reverberation room 10, and the leak hole 13f plays a role of leaking the sound in the reverberation room 10 to the outside. . In the present embodiment, the leakage hole 1
The inner diameter d of 3f is about 70 (mm). Here, the basis for determining the inner diameter d of the leak hole portion 13f as described above will be described.
【００１６】残響室１０内の音の内部音圧レベルの平均
値と周波数との関係を調べたところ、図２にて示すごと
く、グラフＬ０による特性が得られた。また、漏れ孔部
１３ｆの内径ｄ＝５０（ｍｍ）、７０（ｍｍ）及び９０
（ｍｍ）の場合につき、漏れ孔部１３ｆの漏れ音圧レベ
ルと周波数との関係を調べてみたところ、図２にて示す
ごとく、各グラフＬ１、Ｌ２及びＬ３による特性が得ら
れた。When the relationship between the average value of the internal sound pressure level of the sound in the reverberation room 10 and the frequency was examined, the characteristics according to the graph L0 were obtained as shown in FIG. Further, the inner diameter d of the leak hole portion 13f = 50 (mm), 70 (mm) and 90 (mm).
When the relationship between the leak sound pressure level of the leak hole 13f and the frequency was examined in the case of (mm), as shown in FIG. 2, the characteristics according to the graphs L1, L2, and L3 were obtained.
【００１７】これらの結果によれば、各グラフＬ１、Ｌ
２及びＬ３のうちグラフＬ２による漏れ孔部１３ｆの漏
れ音圧レベルの周波数特性が、グラフＬ０による残響室
１０内の内部音圧レベルの平均値の周波数特性とよく一
致していることが分かる。このことは、上述した残響室
１０の非平行な壁形状及び外形寸法のもとでは、内径ｄ
＝７０（ｍｍ）の漏れ孔部１３ｆの場合における漏れ音
圧レベルが、残響室１０内の内部音圧レベル平均値に最
もよく一致することを意味する。According to these results, each graph L1, L
It can be seen that the frequency characteristics of the leak sound pressure level of the leak hole portion 13f according to the graph L2 of the graphs L2 and L3 are in good agreement with the frequency characteristics of the average value of the internal sound pressure levels in the reverberation room 10 according to the graph L0. This means that given the non-parallel wall shape and outer dimensions of the reverberation chamber 10 described above, the inner diameter d
This means that the leak sound pressure level in the case of the leak hole portion 13f of = 70 (mm) best matches the average value of the internal sound pressure levels in the reverberation chamber 10.
【００１８】そこで、漏れ孔部１３ｆの内径ｄを上述の
ごとく７０（ｍｍ）とした。なお、残響室１０の空間の
寸法を変える場合には、この残響室１０の空間の寸法の
変化量に比例して漏れ孔部１３ｆの内径ｄを変えればよ
い。また、漏れ孔部１３ｆの開口は円形状に限ることな
く、四角形等の形状でもよい。一般的には、残響室１０
内の音圧レベル分布を乱さない程度に漏れ孔部１３ｆの
開口面積が設定されていればよい。Therefore, the inner diameter d of the leak hole 13f is set to 70 (mm) as described above. When the size of the space of the reverberation room 10 is changed, the inner diameter d of the leak hole 13f may be changed in proportion to the amount of change in the size of the space of the reverberation room 10. Further, the opening of the leak hole portion 13f is not limited to a circular shape, but may be a square shape or the like. Generally, the reverberation room 10
It is sufficient that the opening area of the leak hole 13f is set so as not to disturb the sound pressure level distribution in the inside.
【００１９】スピーカ２０は、残響室１０内にて側壁１
３ｄの中央にケーシング２０ａを介し装着されており、
このスピーカ２０は、その発音部にて、ケーシング２０
ａの開口を通し残響室１０内に臨んでいる。しかして、
このスピーカ２０は、ランダムノイズ発生器３０から増
幅器４０を通しランダムノイズを受けて残響室１０内に
向け音として発する。The loudspeaker 20 is mounted on the side wall 1 in the reverberation room 10.
It is attached to the center of 3d via the casing 20a,
The speaker 20 has a casing 20
It faces the reverberation room 10 through the opening of “a”. Then
The speaker 20 receives the random noise from the random noise generator 30 through the amplifier 40 and emits the sound as a sound toward the reverberation room 10.
【００２０】なお、ランダムノイズ発生器３０は、１／
３オクターブ又は１／１オクターブのバンドノイズをラ
ンダムノイズとして増幅器４０に出力する。また、増幅
器４０は、ランダムノイズ発生器３０からのランダムノ
イズを増幅してスピーカ２０に出力する。ここで、スピ
ーカ２０と漏れ孔部１３ｆとの間の相対的位置関係につ
いて調べてみた。Note that the random noise generator 30 has 1 /
The band noise of three octaves or 1/1 octave is output to the amplifier 40 as random noise. The amplifier 40 amplifies the random noise from the random noise generator 30 and outputs the amplified noise to the speaker 20. Here, the relative positional relationship between the speaker 20 and the leak hole 13f was examined.
【００２１】残響室１０を小型化しても吸音材に当てる
音は実車相当の音量が必要と考えられる。このため、残
響室１０の小型化に伴い、スピーカ２０の影響がより大
きくなる。従って、漏れ孔部１３ｆをスピーカ２０から
どの程度離せばよいかが問題となる。そこで、残響室１
０の上記空間の寸法を前提に、残響室１０内の音響エネ
ルギー密度Ｅの対数値ｌｏｇＥと、漏れ孔部１３ｆとス
ピーカ２０との間の距離ｒとの関係を調べたところ、図
３にて示すように、グラフＭによる特性として得られ
た。但し、音響エネルギー密度Ｅは、次の数１の式で表
される。It is considered that even if the reverberation room 10 is downsized, the sound applied to the sound absorbing material needs to have a volume equivalent to that of an actual vehicle. For this reason, as the size of the reverberation room 10 is reduced, the influence of the speaker 20 is further increased. Therefore, how much the leakage hole 13f should be separated from the speaker 20 becomes a problem. So, reverberation room 1
The relationship between the logarithmic value logE of the acoustic energy density E in the reverberation chamber 10 and the distance r between the leak hole 13f and the speaker 20 was examined on the assumption that the size of the space was 0, and FIG. As shown, it was obtained as a characteristic according to graph M. However, the acoustic energy density E is represented by the following equation (1).
【００２２】[0022]
【数１】 Ｅ＝（Ｗ／ｃ）〔｛Ｑ／（４πｒ2 ）｝＋（４／Ｒ）〕 ここで、数１の式で、各符号は以下の物理量を表す。 Ｒ：残響室１０の室定数（ｍ2 ） Ｑ：音源指向係数 Ｗ：スピーカ２０の出力（ｗ） ｃ：音速 また、数１の式は、残響室１０内のスピーカ２０と漏れ
孔部１３ｆとの間の距離とスピーカ２０の直接音の寄与
との関係を示す。E = (W / c) [{Q / (4πr 2 )} + (4 / R)] Here, in the expression of Expression 1, each code represents the following physical quantity. R: room constant of the reverberation room 10 (m 2 ) Q: sound source directivity coefficient W: output of the speaker 20 (w) c: sound speed And the contribution of the direct sound of the speaker 20.
【００２３】音響エネルギーは、スピーカ２０からの距
離ｒに関係する直接音の項｛Ｑ／（４πｒ2 ）｝と室内
での吸音効果に関係するいわば反射音の音場を表す項
（４／Ｒ）の和で表される。この和の対数を縦軸に、横
軸に距離を取ったものがグラフＭである。このグラフＭ
によれば、直接音の寄与は、距離ｒの増大に伴い急激に
小さくなり、音響エネルギー密度Ｅは反射音の音場を表
す項の値に収束することが分かる。従って、このグラフ
Ｍの横軸に平行な部分では、反響音が大部分となる。The acoustic energy is a term (Q / (4πr 2 )) relating to the direct sound related to the distance r from the speaker 20 and a term (4 / R) representing the sound field of the reflected sound related to the indoor sound absorbing effect. ). Graph M shows the logarithm of the sum on the vertical axis and the distance on the horizontal axis. This graph M
According to the above, it can be understood that the contribution of the direct sound sharply decreases as the distance r increases, and the acoustic energy density E converges to the value of the term representing the sound field of the reflected sound. Therefore, in the portion parallel to the horizontal axis of the graph M, the reverberation sound becomes the majority.
【００２４】その結果、残響室１０の上記空間の寸法の
もとでは、距離ｒは、約０．５（ｍ）以上でよいことが
分かる。そこで、本実施形態では、残響室１０内のスピ
ーカ２０と漏れ孔部１３ｆとの間の距離が約０．５
（ｍ）以上となるように、漏れ孔部１３ｆの位置を側壁
１３ａの下部に選定した。As a result, it is understood that the distance r may be about 0.5 (m) or more under the size of the space of the reverberation room 10. Therefore, in the present embodiment, the distance between the speaker 20 in the reverberation room 10 and the leak hole 13f is about 0.5.
(M) The position of the leak hole 13f was selected at the lower part of the side wall 13a so as to be more than (m).
【００２５】なお、一般的には、漏れ孔部１３ｆが、残
響室１０内の音が均一に吸音材Ｓ（後述する）の表面に
入るようにスピーカ５０から遠く離れて位置しておれ
ば、吸音材Ｓの全体に亘る平均的な吸音効果を良好に測
定可能である。また、漏れ孔部１３ｆの位置は、側壁１
３ａの下部に限ることなく、例えば、側壁１３ａの上部
でもよい。Generally, if the leak hole 13f is located far from the speaker 50 so that the sound in the reverberation chamber 10 uniformly enters the surface of the sound absorbing material S (described later), The average sound absorbing effect over the entire sound absorbing material S can be measured well. The position of the leak hole 13f is determined by the side wall 1.
The upper part of the side wall 13a is not limited to the lower part of the side wall 3a.
【００２６】被測定対象である吸音材Ｓは、残響室１０
内にてその底壁１１***に置かれている。この吸音材
Ｓは、当該自動車に採用されるもので、長さ４００（ｍ
ｍ）及び幅４００（ｍｍ）の長方形状を有する。なお、
吸音材Ｓは、繊維同士の摩擦作用や、小孔の共鳴作用に
よって音を吸収する綿状、スポンジ状、又は布状等のも
のである。また、吸音材Ｓは、下壁１１に代えて、残響
室１０内にてその上壁１２中央に位置するようにしても
よい。The sound absorbing material S to be measured is placed in the reverberation room 10.
Is located at the center on the bottom wall 11. This sound absorbing material S is employed in the automobile and has a length of 400 (m).
m) and a rectangular shape having a width of 400 (mm). In addition,
The sound absorbing material S is a cotton-like, sponge-like, cloth-like material or the like that absorbs sound by a friction effect between fibers or a resonance effect of small holes. Further, the sound absorbing material S may be located in the center of the upper wall 12 in the reverberation room 10 instead of the lower wall 11.
【００２７】マイクロフォン５０は、残響室１０の外側
にて、漏れ孔部１３ｆの近傍に配置されており、このマ
イクロフォン５０は、残響室１０から漏れ孔部１３ｆを
通り漏出する音を受信して騒音計６０に出力する。騒音
計６０は、マイクロフォン５０の出力に基づき漏れ孔部
１３ｆの漏出音圧レベルを測定する。（１／３）オクタ
ーブ分析方式の分析器７０は、騒音計６０の測定出力を
分析してパーソナルコンピュータ８０に出力する。The microphone 50 is disposed outside the reverberation room 10 and near the leak hole 13f. The microphone 50 receives the sound leaking from the reverberation room 10 through the leak hole 13f and generates noise. Output to a total of 60. The sound level meter 60 measures the leaked sound pressure level of the leak hole 13f based on the output of the microphone 50. The (1/3) octave analysis type analyzer 70 analyzes the measurement output of the sound level meter 60 and outputs it to the personal computer 80.
【００２８】以上のように構成した本実施形態において
は、上述のごとく、残響室１０の各壁は互いに非平行で
表面の滑らかなコンクリートの壁で構成されている。こ
のため、残響室１０の内部で音が不規則に反射し２度と
同じ経路を進行しない。従って、スピーカ２０が、ラン
ダムノイズ発生器３０から増幅器４０を通しランダムノ
イズを受信して残響室１０内に音を発すれば、残響室１
０内での音、即ち、ランダムノイズの周波数特性が変化
しない。このため、このランダムノイズは、残響室１０
内で残響するとともに、ランダムノイズの音圧レベルは
残響室１０内の各所で安定的に保たれる。In the present embodiment configured as described above, as described above, the walls of the reverberation chamber 10 are formed of concrete walls having non-parallel surfaces and smooth surfaces. For this reason, the sound is reflected irregularly inside the reverberation room 10 and does not travel the same path as the second time. Therefore, if the speaker 20 receives the random noise from the random noise generator 30 through the amplifier 40 and emits a sound into the reverberation room 10, the reverberation room 1
The sound within 0, that is, the frequency characteristics of the random noise does not change. Therefore, this random noise is generated in the reverberation room 10
And the sound pressure level of the random noise is stably maintained at various points in the reverberation room 10.
【００２９】よって、残響室１０内に設置した吸音材Ｓ
に音が何度も入射して吸音材の吸音効果を最大限に発揮
させるため、吸音材のある場合とない場合の内部音圧レ
ベルが安定して保たれる。そして、吸音材Ｓが残響室１
０内に有る場合及び無い場合における漏れ孔部１３ｆか
らの漏れ音圧レベルをマイクロフォン５０により受信す
れば、このマイクロフォン５０の各受信出力が、騒音計
６０及び分析器７０を通りパーソナルコンピュータ８０
に入力される。Therefore, the sound absorbing material S installed in the reverberation room 10
In order to maximize the sound-absorbing effect of the sound-absorbing material by causing sound to be incident many times, the internal sound pressure level with and without the sound-absorbing material is stably maintained. The sound absorbing material S is in the reverberation room 1
When the sound pressure level leaking from the leak hole 13f is received by the microphone 50 when the sound pressure level is within 0 and when the sound pressure level does not exist, the received output of the microphone 50 passes through the sound level meter 60 and the analyzer 70 and the personal computer 80.
Is input to
【００３０】すると、パーソナルコンピュータ８０は、
吸音材Ｓの音圧レベル−周波数特性を求めて、この音圧
レベル−周波数特性を、吸音材Ｓの無い場合の音圧レベ
ル−周波数特性と共に表示する。また、パーソナルコン
ピュータ８０は、吸音材Ｓの有る場合と無い場合にマイ
クロフォン５０で測定した音圧の差を求めることによっ
て、吸音材Ｓの吸音効果を測定し得る。Then, the personal computer 80
The sound pressure level-frequency characteristic of the sound absorbing material S is obtained, and the sound pressure level-frequency characteristic is displayed together with the sound pressure level-frequency characteristic when the sound absorbing material S is not provided. Further, the personal computer 80 can measure the sound absorbing effect of the sound absorbing material S by obtaining a difference between sound pressures measured by the microphone 50 when the sound absorbing material S is present and when the sound absorbing material S is not present.
【００３１】この場合、上述のごとく、残響室１０の非
平行な壁形状及び空間の寸法のもとでは、内径ｄ＝７０
（ｍｍ）の漏れ孔部１３ｆの場合の漏れ音圧レベルが残
響室１０内の内部音圧レベル平均値に最もよく一致する
ことから、残響室１０の漏れ孔部１３ｆという一か所か
ら漏出する音圧レベルを測定するという簡単な測定でも
って、残響室１０内の多点計測データの平均値と同様の
値が得られる。In this case, as described above, the inner diameter d = 70 under the non-parallel wall shape and space size of the reverberation room 10.
Since the leak sound pressure level in the case of the leak hole 13f of (mm) best matches the average value of the internal sound pressure level in the reverberation chamber 10, the leak sound leaks from the leak hole 13f of the reverberation chamber 10. With the simple measurement of measuring the sound pressure level, a value similar to the average value of the multi-point measurement data in the reverberation room 10 can be obtained.
【００３２】これにより、残響室１０の小型化及び測定
方法の簡単化を達成しつつ従来の残響式吸音効果測定装
置による測定結果と同等以上の吸音効果を測定できる。
また、吸音材Ｓの大きさは実車に必要な吸音材の大きさ
であるから、残響室１０を上述のように小型化しても、
被測定対象としての吸音材の必要な大きさの上限を充分
にカバーしつつ、良好な吸音効果の測定が可能となる。As a result, it is possible to measure a sound absorbing effect equal to or higher than that obtained by a conventional reverberation type sound absorbing effect measuring device while achieving downsizing of the reverberating room 10 and simplification of the measuring method.
Further, since the size of the sound absorbing material S is the size of the sound absorbing material necessary for the actual vehicle, even if the reverberation room 10 is reduced in size as described above,
It is possible to measure a good sound absorbing effect while sufficiently covering the upper limit of the required size of the sound absorbing material as the object to be measured.
【００３３】また、漏れ孔部１３ｆが残響室１０の最も
面積の小さい側壁１３ａに形成されているから、残響室
１０の残りの内壁面からの反射波を漏れ孔部１３ｆにお
いて最も多く獲得できる。従って、残響室１０内の音量
を最も有効に利用できるから、マイクロフォン５０によ
る受信漏れ音量も充分に確保できる。なお、残響室１０
の小型化は、Ｓ／ｎ比の悪化を招くから、スピーカ２０
から定常的に音を出し続けることで、吸音材の吸音効果
を測定する。これにより、Ｓ／ｎ比が向上し得る。Further, since the leak hole 13f is formed on the side wall 13a having the smallest area of the reverberation chamber 10, the reflected wave from the remaining inner wall surface of the reverberation chamber 10 can be obtained most in the leak hole 13f. Therefore, since the sound volume in the reverberation room 10 can be used most effectively, the sound leakage due to the microphone 50 can be sufficiently ensured. The reverberation room 10
Since the miniaturization of the speaker causes the deterioration of the S / n ratio, the speaker 20
, The sound absorbing effect of the sound absorbing material is measured by continuously emitting sound. Thereby, the S / n ratio can be improved.
【００３４】図４は、吸音材Ｓとして、厚さや構造密度
等が異なる５種類の吸音材Ｓａ乃至Ｓｅを採用し、これ
ら吸音材Ｓａ乃至Ｓｅの吸音効果につき、本発明装置に
より測定した場合の吸音効果の序列と、従来の残響式測
定装置により測定した場合吸音効果の序列と、実車での
吸音効果の序列との対応を示す。なお、吸音材Ｓｃは、
内部に空気層を持つ吸音材である。吸音材Ｓｄは表面に
アルミ箔を張った吸音材である。FIG. 4 shows a case where five kinds of sound absorbing materials Sa to Se having different thicknesses, structural densities and the like are used as the sound absorbing material S, and the sound absorbing effects of these sound absorbing materials Sa to Se are measured by the apparatus of the present invention. The order of the sound absorbing effect, the order of the sound absorbing effect when measured by a conventional reverberation type measuring device, and the order of the sound absorbing effect in an actual vehicle are shown. The sound absorbing material Sc is
Sound absorbing material with an air layer inside. The sound absorbing material Sd is a sound absorbing material whose surface is covered with aluminum foil.
【００３５】図４によれば、上記各吸音材Ｓａ乃至Ｓｅ
では、本発明装置による測定結果は、その序列におい
て、実車や従来の残響室測定装置による場合の測定結果
とよく対応していることが分かる。なお、本発明の実施
にあたっては、自動車用吸音材に限ることなく、一般建
築物用吸音材等の各種の吸音材の吸音効果を測定するに
あたり、本発明を適用してもよい。According to FIG. 4, each of the sound absorbing materials Sa to Se is described.
It can be seen that the measurement results obtained by the apparatus of the present invention in the order correspond well to the measurement results obtained by the actual vehicle and the conventional reverberation room measurement apparatus. In practicing the present invention, the present invention may be applied to measuring the sound absorbing effect of various sound absorbing materials such as sound absorbing materials for general buildings, without being limited to the sound absorbing material for automobiles.
【００３６】また、本発明の実施にあたり、残響室１０
の外形形状及び外形寸法は、上記実施形態に述べたもの
に限ることなく、非平行な壁形状及び小型形状を満たす
ことを前提に、必要に応じて適宜変更してもよい。In implementing the present invention, the reverberation room 10
The external shape and external dimensions of are not limited to those described in the above embodiment, and may be appropriately changed as necessary on the assumption that non-parallel wall shapes and small shapes are satisfied.
【図１】本発明の一実施形態を示す概略全体構成図であ
る。FIG. 1 is a schematic overall configuration diagram showing an embodiment of the present invention.
【図２】漏れ孔部の内径をパラメータとして、内部音圧
レベル及び漏れ音圧レベルと周波数との関係を示すグラ
フである。FIG. 2 is a graph showing a relationship between an internal sound pressure level and a leak sound pressure level and a frequency, using an inner diameter of a leak hole as a parameter.
【図３】エネルギー密度の漏れ孔部とスピーカとの間の
距離との関係を示すグラフである。FIG. 3 is a graph showing the relationship between the energy density and the distance between a leak hole and a speaker.
【図４】各種の吸音材の吸音効果を、上記実施形態の吸
音効果測定装置、従来の吸音効果測定装置及び実車によ
り測定した結果を示すグラフである。FIG. 4 is a graph showing the results of measuring the sound absorbing effect of various sound absorbing materials using the sound absorbing effect measuring device of the embodiment, the conventional sound absorbing effect measuring device, and an actual vehicle.
【図５】（ａ）は、従来の残響式吸音効果測定装置の残
響室を示す図であり、（ｂ）は、当該測定装置による音
圧レベルの時間に伴う減衰する傾向を示すグラフであ
る。FIG. 5A is a diagram showing a reverberation chamber of a conventional reverberation-type sound absorbing effect measuring device, and FIG. 5B is a graph showing a tendency of the sound pressure level of the measuring device to attenuate with time. .
Ｓ…吸音材、１０…残響室、１３ｆ…漏れ孔部、２０…
スピーカ、３０…ランダムノイズ発生器、４０…増幅
器、５０…マイクロフォン、６０…騒音計、８０…パー
ソナルコンピュータ。S: sound absorbing material, 10: reverberation room, 13f: leak hole portion, 20:
Speaker, 30: random noise generator, 40: amplifier, 50: microphone, 60: sound level meter, 80: personal computer.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 稲垣 光夫 愛知県西尾市下羽角町岩谷14番地 株式会 社日本自動車部品総合研究所内 (72)発明者 野場 幹雄 愛知県豊田市トヨタ町１番地 トヨタ自動 車株式会社内 (72)発明者 河合 保 愛知県豊田市トヨタ町１番地 トヨタ自動 車株式会社内 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mitsuo Inagaki 14 Iwatani, Shimowasumi-cho, Nishio-shi, Aichi Prefecture Inside Japan Automotive Parts Research Institute Co., Ltd. (72) Mikio Noba 1st Toyota Town, Toyota-shi, Toyota-shi, Aichi Toyota Motor (72) Inventor Tamotsu Kawai 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation
Claims (4)
乃至１３ｅ）からなるとともにこれら複数の壁の一部分
に漏れ孔部（１３ｆ）を形成してなる残響室（１０）
と、 前記複数の壁の他の部分に設けたスピーカ（２０）を備
え、このスピーカから前記残響室内にランダム音を発し
前記残響室内に前記非平行な壁形状のもと平均的音圧レ
ベルの音場を形成するランダム音発生手段（３０、４
０）と、 前記残響室内に吸音材を配置した状態で前記漏れ孔部か
ら漏出する音を検出するマイクロフォン（５０）とを備
え、 このマイクロフォンの検出出力に基づき前記吸音材の吸
音効果を測定するようにした残響式吸音効果測定装置。A plurality of non-parallel walls (11,12,13a)
To a reverberation chamber (10) comprising a leak hole (13f) formed in a part of the plurality of walls.
And a speaker (20) provided on the other part of the plurality of walls, wherein the speaker emits a random sound into the reverberation chamber and has an average sound pressure level based on the non-parallel wall shape in the reverberation chamber. Means for generating a random sound (30, 4
0), and a microphone (50) for detecting sound leaking from the leak hole with the sound absorbing material disposed in the reverberation room, and measuring a sound absorbing effect of the sound absorbing material based on a detection output of the microphone. Reverberation-type sound absorption effect measuring device.
一に前記吸音材の表面に入るように前記スピーカから遠
く離れて位置することを特徴とする請求項１に記載の残
響式吸音効果測定装置。2. The reverberation type sound absorbing device according to claim 1, wherein the leak hole portion is located far away from the speaker so that sound in the reverberation chamber uniformly enters the surface of the sound absorbing material. Effect measurement device.
内の音圧レベル分布を乱さない程度に設定されているこ
とを特徴とする請求項１又は２に記載の残響式吸音効果
測定装置。3. The reverberation-type sound absorption effect measuring apparatus according to claim 1, wherein an opening area of the leak hole is set so as not to disturb a sound pressure level distribution in the reverberation chamber. .
も面積の小さい壁に形成されていることを特徴とする請
求項１乃至３のいずれか一つに記載の残響式吸音効果測
定装置。4. The reverberation type sound absorption effect measurement according to claim 1, wherein the leak hole is formed in a wall having the smallest area among the plurality of walls. apparatus.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP06809497A JP3324432B2 (en) | 1997-03-21 | 1997-03-21 | Reverberation type sound absorption measurement device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP06809497A JP3324432B2 (en) | 1997-03-21 | 1997-03-21 | Reverberation type sound absorption measurement device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH10260168A true JPH10260168A (en) | 1998-09-29 |
| JP3324432B2 JP3324432B2 (en) | 2002-09-17 |
Family
ID=13363814
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|---|---|---|---|
| JP06809497A Expired - Fee Related JP3324432B2 (en) | 1997-03-21 | 1997-03-21 | Reverberation type sound absorption measurement device |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002532689A (en) * | 1998-12-07 | 2002-10-02 | タレス ネーデルラント ベスローテン フェンノートシャップ | Test room |
| JP2007078472A (en) * | 2005-09-13 | 2007-03-29 | Ihi Aerospace Co Ltd | Immersion type ultrasonic flaw detector |
| JP2013019817A (en) * | 2011-07-12 | 2013-01-31 | Misuzu Kogyo:Kk | Micropore inspection apparatus and micropore inspection method |
| CN103713046A (en) * | 2014-01-08 | 2014-04-09 | 神龙汽车有限公司 | Measuring method and device for sound-proofing quantity of perforation structure assembly |
| CN113237955A (en) * | 2021-05-21 | 2021-08-10 | 安徽江淮汽车集团股份有限公司 | Method and system for testing sound absorption performance of molding material |
| CN117847000A (en) * | 2024-03-07 | 2024-04-09 | 山东省东澎冷暖工程有限公司 | Fan operation noise detection device |
-
1997
- 1997-03-21 JP JP06809497A patent/JP3324432B2/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002532689A (en) * | 1998-12-07 | 2002-10-02 | タレス ネーデルラント ベスローテン フェンノートシャップ | Test room |
| JP2007078472A (en) * | 2005-09-13 | 2007-03-29 | Ihi Aerospace Co Ltd | Immersion type ultrasonic flaw detector |
| JP2013019817A (en) * | 2011-07-12 | 2013-01-31 | Misuzu Kogyo:Kk | Micropore inspection apparatus and micropore inspection method |
| CN103713046A (en) * | 2014-01-08 | 2014-04-09 | 神龙汽车有限公司 | Measuring method and device for sound-proofing quantity of perforation structure assembly |
| CN113237955A (en) * | 2021-05-21 | 2021-08-10 | 安徽江淮汽车集团股份有限公司 | Method and system for testing sound absorption performance of molding material |
| CN117847000A (en) * | 2024-03-07 | 2024-04-09 | 山东省东澎冷暖工程有限公司 | Fan operation noise detection device |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3324432B2 (en) | 2002-09-17 |
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