【考案の詳細な説明】[Detailed explanation of the idea]
本考案は新規なスピーカー用キヤビネツト材料
に関するものである。
始めに、本考案を想到するに至つた経緯につい
て簡単に述べると、市販の建築材料のなかにはセ
メントや石膏を原料とした水硬性無機板状体があ
り、不燃材料として確たる地位を築いていること
については従来周知である。しかし、かかる水硬
性無機板状体の使用分野は建材関係に限られてい
た訳であるから、それ以外の分野にも広く使用で
きる用途が開発されたならば、当業界に及ぼす便
益は甚だ大なるものである。ところが斯様な狙い
のもとになされた発明考案については寡聞にして
知らない。
本考案者等は叙上の如き実情に鑑み、市場の流
通量も多く、入手が容易で、しかも安価であると
いつた多くの利点をもつている市販の水硬性無機
板状体をそのままスピーカー用キヤビネツト材料
として使用できないかと考えた。一般にスピーカ
ー用キヤビネツト材料として要求される性質に
は、イ．剛性弾性率が大きく機械的強度が高いこ
と、ロ．共振尖鋭度（Ｑ）が小さいこと、ハ．面
密度が高いこと、ニ．製作するうえで加工性が優
れていること等が挙げられる。実際に試験した結
果は下表に示すとおりであり、共振尖鋭度（Ｑ）
の値が高くて、それ自体ではスピーカー用キヤビ
ネツト材料として不向きであることがわかつた。
The present invention relates to a novel speaker cabinet material. First, to briefly explain how we came up with this idea, there are hydraulic inorganic plates made from cement and gypsum among commercially available building materials, and they have established a solid position as noncombustible materials. is well known in the past. However, since the field of use of such hydraulic inorganic plates has been limited to construction materials, if a wide range of applications were developed in other fields, the benefits to this industry would be enormous. It is what it is. However, I have very little knowledge of inventions and ideas that were made with such a goal in mind. In view of the above-mentioned circumstances, the inventors of the present invention have decided to use a commercially available hydraulic inorganic plate-like material as it is as a speaker, which has many advantages such as being widely distributed in the market, easy to obtain, and inexpensive. I wondered if it could be used as a material for cabinets. Properties generally required for speaker cabinet materials include: High rigidity-elastic modulus and high mechanical strength; b. Resonance sharpness (Q) is small; c. High areal density, d. Among other things, it has excellent workability in manufacturing. The actual test results are shown in the table below, and the resonance sharpness (Q)
It was found that the material had a high value of , making it unsuitable as a speaker cabinet material on its own.
【表】【table】
【表】
キヤビネツトの振動レベルは、構成材料の面密
度（比重×板厚）及び弾性率が高い程低くなり、
共振尖鋭度（Ｑ）が小さい程共振点での振動レベ
ルが低くなる。弾性率と共振尖鋭度（Ｑ）の関係
は、通常、弾性率を上げると共振尖鋭度（Ｑ）も
大きくなり、逆に共振尖鋭度（Ｑ）を小さくする
と弾性率も下がるというように両者相反する傾向
があり、両者を満足させることはむつかしい問題
であつた。
本考案者等は不燃材料である水硬性無機板状体
を芯材とし、その表面に硬質繊維板を貼着するこ
とにより、これら条件をすべて満たす材料を得こ
とができることを見出し、本考案を完成するに至
つたものである。
すなわち本考案は、曲型的には図面に示すよう
に、水硬性無機板状体１を芯材とし、その両表面
に硬質繊維板２を貼着一体化した構成のものであ
る。もつとも硬質繊維板２は水硬性無機板状体１
の片面のみに貼着された構成でもよい。ただし片
面構成にすると表裏面での条件が異なるため反り
が生じ易く、共振尖鋭度（Ｑ）が大きくなるた
め、図示の如き両面貼着構成の方が好ましい。本
考案で使用することができる不燃材料である水硬
性無機板状体１としては、石膏板、石綿セメント
板、エトリンガイト系セメント板、珪酸カルシウ
ム系石綿セメント板、炭酸マグネシウム系成型板
等であり、比重は0.9以上の緻密なものが適する。
厚みは通常10〜25mm程度のものを用いる。また植
物繊維を主原料としたボードである硬質繊維板２
は比重0.8以上のもので、厚みは約２mm程度でよ
い。硬質繊維板２を水硬性無機板状体１の片面ま
たは両面に貼着するための接着剤としては例えば
酢酸ビニル系接着剤がある。
本考案の効果はつぎに述べる性能比較から明ら
かである。すなわち、前に表記した合計８種類の
水硬性無機板状体（厚さは何れも11mmとした）に
厚さ２mmの硬質繊維板を両面貼着構成および片面
貼着構成としたときの共振尖鋭度、比重、動弾性
率の測定結果は、下表のとおりである。種類を示
す番号はそれぞれ符号している。尚、従来使用さ
れている15mm厚のラワン合板およびパーテイクル
ボードの共振尖鋭度はそれぞれ73，45、比重はそ
れぞれ0.50，0.73、動弾性率は4.85×104Kg／cm2、
4.35×104Kg／cm2であるが、本考案のスピーカー
用キヤビネツト材料は従来品と比較し、動弾性率
はほとんど変らないが、比重が約２倍高く、しか
も共振尖鋭度（Ｑ）が小さい優れた材料であると
いえる。[Table] The vibration level of the cabinet decreases as the areal density (specific gravity x plate thickness) and elastic modulus of the constituent materials increase.
The smaller the resonance sharpness (Q), the lower the vibration level at the resonance point. The relationship between elastic modulus and resonance sharpness (Q) is usually contradictory, such that as the elastic modulus increases, the resonance sharpness (Q) also increases, and conversely, as the resonance sharpness (Q) decreases, the elastic modulus decreases. This made it difficult to satisfy both parties. The present inventors discovered that a material that satisfies all of these conditions could be obtained by using a hydraulic inorganic plate-like material, which is a non-combustible material, as the core material and pasting hard fiberboard on the surface of the core material, and developed the present invention. It has come to completion. That is, as shown in the drawings, the present invention has a structure in which a hydraulic inorganic plate-like body 1 is used as a core material, and hard fiberboards 2 are attached and integrated on both surfaces thereof. The hard fiberboard 2 is actually a hydraulic inorganic plate-like body 1
The structure may be such that it is attached only to one side. However, if a single-sided structure is used, warping is likely to occur because the conditions on the front and back surfaces are different, and the resonance sharpness (Q) becomes large. Therefore, a double-sided bonding structure as shown in the drawing is preferable. The hydraulic inorganic plate-like body 1 which is a noncombustible material that can be used in the present invention includes a gypsum board, an asbestos cement board, an ettringite cement board, a calcium silicate-based asbestos cement board, a magnesium carbonate molded board, etc. A dense material with a specific gravity of 0.9 or higher is suitable.
The thickness is usually about 10 to 25 mm. In addition, hard fiberboard 2 is a board made mainly of plant fibers.
has a specific gravity of 0.8 or more and a thickness of approximately 2 mm. An example of an adhesive for attaching the hard fiberboard 2 to one or both sides of the hydraulic inorganic plate-like body 1 is a vinyl acetate adhesive. The effectiveness of the present invention is clear from the performance comparison described below. In other words, the resonance sharpness when a hard fiberboard with a thickness of 2 mm is attached on both sides and on one side to the previously described eight types of hydraulic inorganic plate-like bodies (thickness of each was 11 mm). The measurement results of elasticity, specific gravity, and dynamic elastic modulus are shown in the table below. The numbers indicating the type are each coded. In addition, the resonance acuity of the conventionally used 15 mm thick lauan plywood and particle board is 73 and 45, respectively, the specific gravity is 0.50 and 0.73, respectively, and the dynamic elastic modulus is 4.85 × 10 4 Kg/cm 2 .
4.35×10 4 Kg/cm 2 .Compared to conventional products, the speaker cabinet material of the present invention has almost no change in dynamic elastic modulus, but its specific gravity is approximately twice as high, and the resonance sharpness (Q) is It can be said that it is a small and excellent material.
【表】
次に本考案によるスピーカー用キヤビネツト材
料を用いて、幅230mm×高さ385mm×奥行243mm
（板厚15mm）のスピーカー用キヤビネツトを作り、
従来使用されている材料によるキヤビネツトと比
較した。その結果、本考案に係る材料を用いたも
のは、比重が高い為振動レベルが低く、しかも共
振尖鋭度（Ｑ）が小さいため、キヤビネツトの共
振が殆んど無いので、低音域において従来品より
音の伸びがあつて、中高音域では音の出が鮮明で
あつて美しく、極めて良好な音響特性が得られる
ことが認められた。
本考案は上記のように構成したスピーカー用キ
ヤビネツト材料であるから、遮音特性が良く、共
振尖鋭度（Ｑ）が小さく、振動レベルを低くでき
るので、スピーカーとして組立てたとき低音域に
おいて音の伸びがあり、中音域では音の出が鮮明
で美しい極めて良好な音響特性が得られるという
実用上すぐれた効果を奏しうるものである。[Table] Next, using the speaker cabinet material of the present invention, a width of 230 mm x height of 385 mm x depth of 243 mm was created.
(Plate thickness: 15mm) I made a speaker cabinet.
A comparison was made with a cabinet made of conventionally used materials. As a result, products using the material according to the present invention have a high specific gravity, so the vibration level is low, and the resonance sharpness (Q) is small, so there is almost no resonance in the cabinet, so it is better than conventional products in the bass range. It was recognized that the sound was extended, the sound output was clear and beautiful in the mid-to-high range, and extremely good acoustic characteristics were obtained. Since the present invention is a speaker cabinet material constructed as described above, it has good sound insulation properties, low resonance sharpness (Q), and can reduce vibration levels, so when assembled as a speaker, sound extension in the bass range is improved. This has an excellent practical effect in that in the midrange, the sound is clear and beautiful, and extremely good acoustic characteristics can be obtained.
【図面の簡単な説明】[Brief explanation of the drawing]
図面は本考案によるスピーカー用キヤビネツト
材料の断面図である。
１……水硬性無機板状体、２……硬質繊維板。
The drawing is a cross-sectional view of a speaker cabinet material according to the present invention. 1...Hydraulic inorganic plate-like body, 2...Hard fiberboard.