JPS6351636B2 - - Google Patents

Info

Publication number
JPS6351636B2
JPS6351636B2 JP7094383A JP7094383A JPS6351636B2 JP S6351636 B2 JPS6351636 B2 JP S6351636B2 JP 7094383 A JP7094383 A JP 7094383A JP 7094383 A JP7094383 A JP 7094383A JP S6351636 B2 JPS6351636 B2 JP S6351636B2
Authority
JP
Japan
Prior art keywords
enclosure
speaker
mode
sound pressure
sound
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.)
Expired
Application number
JP7094383A
Other languages
Japanese (ja)
Other versions
JPS59196691A (en
Inventor
Shinichi Sakai
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mitsubishi Electric Corp
Original Assignee
Mitsubishi Electric Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Mitsubishi Electric Corp filed Critical Mitsubishi Electric Corp
Priority to JP7094383A priority Critical patent/JPS59196691A/en
Publication of JPS59196691A publication Critical patent/JPS59196691A/en
Publication of JPS6351636B2 publication Critical patent/JPS6351636B2/ja
Granted legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R1/00—Details of transducers, loudspeakers or microphones
    • H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
    • H04R1/22—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only 
    • H04R1/28—Transducer mountings or enclosures modified by provision of mechanical or acoustic impedances, e.g. resonator, damping means
    • H04R1/2869—Reduction of undesired resonances, i.e. standing waves within enclosure, or of undesired vibrations, i.e. of the enclosure itself
    • H04R1/2884—Reduction of undesired resonances, i.e. standing waves within enclosure, or of undesired vibrations, i.e. of the enclosure itself by means of the enclosure structure, i.e. strengthening or shape of the enclosure
    • H04R1/2888—Reduction of undesired resonances, i.e. standing waves within enclosure, or of undesired vibrations, i.e. of the enclosure itself by means of the enclosure structure, i.e. strengthening or shape of the enclosure for loudspeaker transducers

Landscapes

  • Health & Medical Sciences (AREA)
  • Otolaryngology (AREA)
  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Details Of Audible-Bandwidth Transducers (AREA)
  • Obtaining Desirable Characteristics In Audible-Bandwidth Transducers (AREA)

Description

【発明の詳細な説明】 本発明は低音用スピーカをエンクロージヤのバ
ツフル面に取付けて成るスピーカ装置の改良に関
する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a speaker device in which a bass speaker is attached to a buttful surface of an enclosure.

第１図は従来のこの種の２ウエイスピーカ装置
を示し、１は直方体のエンクロージヤ、２はエン
クロージヤ１のバツフル面、３，４はバツフル面
２に取付けられた、それぞれ、低音用スピーカ、
高音用スピーカである。 FIG. 1 shows a conventional two-way speaker device of this type, in which 1 is a rectangular parallelepiped enclosure, 2 is a butt-full surface of the enclosure 1, and 3 and 4 are bass speakers attached to the butt-full surface 2, respectively;
This is a high-pitched speaker.

第２図は上記装置によつて放射される音波の、
バツフル面２の正面遠方での、音圧周波数特性を
示し、実線ａは総合特性であり、点線ｂ，ｃはそ
れぞれ低音用スピーカ３、高音用スピーカ４だけ
を駆動した時の特性である。 Figure 2 shows the sound waves emitted by the above device.
The sound pressure frequency characteristics are shown in the far front direction of the buff-full surface 2, where the solid line a is the overall characteristic, and the dotted lines b and c are the characteristics when only the bass speaker 3 and the treble speaker 4 are driven, respectively.

ところで、上記装置では、低音用スピーカ３を
駆動すると、エンクロージヤ１内に固有の共振、
すなわち、定在波が起こることが知られている。
この定在波は、低音用スピーカ３から放射される
音波の音圧特性に影響を与えてピークやデイツプ
を生じさせ、音質を劣化させる要因となる。この
定在波対策としてエンクロージヤ１の内壁に吸音
材を貼つているが、それでも、第２図に示した特
性ｂのように、低音用スピーカ３の再生帯域に乱
れが生じている。 By the way, in the above device, when the bass speaker 3 is driven, a unique resonance occurs within the enclosure 1.
In other words, it is known that standing waves occur.
This standing wave affects the sound pressure characteristics of the sound waves radiated from the bass speaker 3, causing peaks and dips, and becomes a factor in deteriorating the sound quality. As a countermeasure against this standing wave, a sound absorbing material is attached to the inner wall of the enclosure 1, but even so, as shown in characteristic b shown in FIG. 2, the reproduction band of the bass speaker 3 is disturbed.

そして、エンクロージヤ１のような直方体の閉
じた音場で起こる固有の共振周波数frは次式のと
おりであることも知られている。 It is also known that the unique resonance frequency f r that occurs in a rectangular closed sound field such as the enclosure 1 is expressed by the following equation.

ここで、ｃは音速、Ｈ、Ｗ、Ｄは直方体音場の
上下、左右、前後各方向の寸法、nH、nW、nDは
Ｈ、Ｗ、Ｄに対応した定在波のモードを表わす整
数（０、１、２、……）である。 Here, c is the speed of sound, H, W, and D are the vertical, horizontal, and longitudinal dimensions of the rectangular parallelepiped sound field, and n H , n W , and n D are the modes of the standing waves corresponding to H, W, and D. It is an integer (0, 1, 2, . . .) representing the value.

上記(1)式で計算できるようにエンクロージヤ１
の一辺が音波の波長の半分、その整数倍になる一
方向のみのモード（nH、nW、nDのうちの二つが０
−このモードは軸モードと呼ばれる）、さらに、
二方向以上のモードが重なり合うモード（nH、
nW、nDのうちの二つ以上が０でない）が形成さ
れる周波数で定在波が多数生ずる。 Enclosure 1 so that it can be calculated using formula (1) above.
A unidirectional mode where one side is half the wavelength of the sound wave and an integer multiple thereof (two of n H , n W , and n D are 0
- this mode is called axial mode), and furthermore,
A mode in which modes in two or more directions overlap (n H ,
A large number of standing waves are generated at frequencies where two or more of n W and n D are not 0).

また、(1)式で表わされる周波数で定在波が生ず
る場合には、エンクロージヤ内の音圧または粒子
速度分布が固有な分布となることも知られてお
り、第３図に一方向のみのモード（軸モード）に
関する１〜３次の分布例を示す。同図の横軸は距
離で両端がエンクロージヤの端面に相当し、縦軸
は音圧または粒子速度の最大値で規格化した値で
あり、実線、点線はそれぞれ音圧、粒子速度を表
わし、特性ａ，ｂ，ｃの順に軸モードの１次、２
次、３次の分布である。 It is also known that when a standing wave is generated at the frequency expressed by equation (1), the sound pressure or particle velocity distribution within the enclosure becomes a unique distribution. An example of first to third order distribution regarding the mode (axial mode) is shown. The horizontal axis in the figure is distance, with both ends corresponding to the end faces of the enclosure, and the vertical axis is the value normalized by the maximum value of sound pressure or particle velocity, and the solid line and dotted line represent sound pressure and particle velocity, respectively. Characteristics a, b, c in the order of the 1st and 2nd order of the axial modes.
This is a third-order distribution.

定在波対策として、第３図の定在波モードを考
慮した方法もとられる。すなわち、定在波音圧モ
ードの節（音圧０）の位置に低音用スピーカを取
付ける方法で、低音用スピーカの中心を音圧モー
ドの節にほぼ一致させれば、そのモードを発生さ
せる定在波は励起されない。この方法を、以下、
節駆動と呼ぶことにする。 As a countermeasure against standing waves, a method that takes into consideration the standing wave mode shown in FIG. 3 is also taken. In other words, by installing a bass speaker at the node of the standing wave sound pressure mode (sound pressure 0), if the center of the bass speaker is approximately aligned with the node of the sound pressure mode, the stationary wave that generates that mode can be installed. Waves are not excited. This method is explained below.
We will call it node drive.

上記節駆動は、従来装置の低音用スピーカ３を
取付けたバツフル面２と平行な上下、左右各方向
に生ずる定在波に対しては有効であるが、バツフ
ル面２と垂直な前後方向に生ずる定在波に対して
は、構造上の制約により、無効である。低音用ス
ピーカ３は、第３図のモード図でいえばその左、
右どちらか一端にあり、前後方向に生ずる定在波
の音圧モードの腹の位置を駆動するからである。 The above-mentioned nodal drive is effective against standing waves that occur in the vertical and horizontal directions parallel to the buff-full surface 2 on which the bass speaker 3 of the conventional device is attached, but it is effective against standing waves that occur in the front-rear direction perpendicular to the buff-full surface 2. It is ineffective for standing waves due to structural constraints. Bass speaker 3 is on the left side in the mode diagram of Figure 3.
This is because it is located at one end of the right side and drives the position of the antinode of the sound pressure mode of the standing wave that occurs in the front-rear direction.

従来装置には、上記のように、エンクロージヤ
内に前後方向の定在波が必らず励起されてしま
い、その結果、音圧特性に乱れが生ずるという欠
点がある。 As described above, the conventional device has the disadvantage that standing waves in the front-rear direction are necessarily excited within the enclosure, resulting in disturbances in the sound pressure characteristics.

本発明は、従来装置の上記欠点を除去すること
を目的とし、このため、エンクロージヤを、内部
が、上下両端を閉止した円筒をその中心軸を含む
少なくとも一平面により二つに切断した、その一
方の形状をなすものとし、かつ、低音用スピーカ
をエンクロージヤの上記円筒としての中心軸上に
取付けるものである。 SUMMARY OF THE INVENTION The present invention aims to eliminate the above-mentioned drawbacks of conventional devices, and for this purpose, an enclosure is constructed of an enclosure in which the interior is a cylinder whose upper and lower ends are closed, and which is cut into two by at least one plane including its central axis. A bass speaker is mounted on the central axis of the cylindrical enclosure.

第４図は本発明の一実施例を示し、ａは正面
図、ｂはａの−に沿つた水平横断面図、１〜
３は第１図におけると同じく、それぞれ、エンク
ロージヤ、バツフル面、低音用スピーカ、５はエ
ンクロージヤ１の円筒面であるが、(イ)エンクロー
ジヤ１は内部が、上下両端を閉止した円筒をその
中心軸を含む平面により二つに切断した、その一
方の半円筒状をなすものであり、(ロ)バツフル面２
は上記切断平面であり、(ハ)低音用スピーカ３は上
記中心軸上、すなわち、バツフル面２の左右方向
の中央に取付けられている、ものである。 FIG. 4 shows an embodiment of the present invention, in which a is a front view, b is a horizontal cross-sectional view taken along - of a, and 1 to 4.
As in Fig. 1, 3 is an enclosure, a full surface, and a bass speaker, respectively, and 5 is a cylindrical surface of the enclosure 1. It has a semi-cylindrical shape, one of which is cut into two by a plane that includes the central axis, and (b) a full surface 2.
is the above-mentioned cutting plane, and (c) the bass speaker 3 is mounted on the above-mentioned central axis, that is, at the center of the buff-full surface 2 in the left-right direction.

上記実施例のエンクロージヤ１の半円筒内に起
こる定在波は円筒音場のそれから推定することが
できる。円筒音場では次式の固有周波数fcで共振
（定在波）が起こることが知られている。すなわ
ち、 fc＝Ｃ／２ αmn／Ｒ ……(2) ここで、Ｃは音速、Ｒは円筒の半径、αmnは
dJm（πα）／dαのｎ番目の根（dJm（παmn）dα＝0.
Jm （πα）はベツセル関数）、ｍ、ｎは０以上の整数
で、ｍが周方向の、ｎが径方向のモードを表わす
次数である。(2)式の周波数fcにおける固有モード
を周波数の低い順に図示すると、第５図ａ〜ｈと
なる。同図において、点線は円筒音場の音圧モー
ドの節を示し、その節は円筒横断面を2m分また
は2n分するように生ずる。たとえば、ｍ＝２の
場合、節は中心を通り周方向を４等分するように
生ずる（第５図ｂ）。また、実線は半円筒にする
場合の円筒切断平面を示し、その場合に切断平面
が周方向音圧モードの腹となるようにモードは生
ずる。したがつて、半円筒にする場合には、径方
向だけのモード（ｍ＝０、ｎ＞０）は生じないこ
とになる。 The standing waves occurring within the semi-cylinder of the enclosure 1 of the above embodiment can be estimated from that of the cylindrical sound field. It is known that resonance (standing wave) occurs in a cylindrical sound field at the natural frequency f c of the following equation. That is, f c = C/2 αmn/R ...(2) Here, C is the speed of sound, R is the radius of the cylinder, and αmn is
nth root of dJm(πα)/dα (dJm(παmn)dα=0.
Jm (πα) is a Betzel function), m and n are integers greater than or equal to 0, where m is an order representing a circumferential mode and n is an order representing a radial mode. If the eigenmodes at the frequency f c of equation (2) are illustrated in descending order of frequency, they are shown in FIGS. 5a to 5h. In the figure, dotted lines indicate nodes of the sound pressure mode of the cylindrical sound field, and the nodes occur so as to cover the cylindrical cross section by 2m or 2n. For example, when m=2, the nodes are generated so as to pass through the center and equally divide the circumferential direction into four (FIG. 5b). Further, the solid line indicates the cylinder cutting plane when forming a semi-cylindrical cylinder, and in this case, a mode is generated such that the cutting plane becomes the antinode of the circumferential sound pressure mode. Therefore, in the case of a semi-cylindrical shape, a mode only in the radial direction (m=0, n>0) will not occur.

このため、上記実施例では、その(イ)、すなわ
ち、エンクロージヤ１の内部が半円筒状であるこ
とにより、 (i) 音圧モードの節の位置が限定され、 (ii) 径方向だけのモードは生ぜず、 (iii) 周方向モードの節は円筒の中心を通り、この
ため、円筒切断平面の中央に節が集中する ことになる。そして、この(iii)から、その(ハ)、すな
わち、低音用スピーカ３が切断平面の中央に取付
けられていることにより、円筒音場に関する節駆
動が達成されることになる。このように、上記実
施例は、その(イ)、(ハ)により、円筒音場のモードに
関する定在波をすべて励起しないものとなる。 Therefore, in the above embodiment, due to (a), that is, the inside of the enclosure 1 is semi-cylindrical, (i) the position of the node of the sound pressure mode is limited, and (ii) the position of the node in the sound pressure mode is limited, and (ii) the position of the node in the sound pressure mode is No mode is generated, and (iii) the nodes of the circumferential mode pass through the center of the cylinder, so the nodes are concentrated at the center of the cylinder cutting plane. From this (iii), it follows that (c), that is, by installing the bass speaker 3 at the center of the cutting plane, nodal drive regarding the cylindrical sound field is achieved. Thus, in the above embodiment, due to (a) and (c), all standing waves related to the modes of the cylindrical sound field are not excited.

本発明のエンクロージヤの内部は、上記実施例
の半円筒状のものに限定されるものでなく、円筒
をその中心軸を含む二平面により二つに切断した
その一方のもの、すなわち、第６図ａ，ｂに示す
ようなものであつてもよい。同図ａは切断二平面
のなす角度180゜よりも小としたもの、同図ｂは上
記角度を180゜よりも大としたものであり、エンク
ロージヤ１の水平横断面は扇形をなしており、い
ずれも、上記実施例のエンクロージヤ１と全く同
じ動作をする。 The inside of the enclosure of the present invention is not limited to the semi-cylindrical shape of the above embodiment, but can be formed by cutting a cylinder into two by two planes including the central axis, that is, the sixth half. It may be as shown in Figures a and b. In Figure a, the angle formed by the two cutting planes is smaller than 180°, and in Figure b, the angle is larger than 180°, and the horizontal cross section of enclosure 1 is fan-shaped. , all operate exactly the same as the enclosure 1 of the above embodiment.

本発明のエンクロージヤにも、従来装置の直方
体エンクロージヤと同じく、上下方向（円筒の中
心軸方向）の定在波が起こるが、従来装置につい
て述べたように、低音用スピーカの取付位置をそ
の定在波モードの節の位置としてその対策とする
ことができる。 In the enclosure of the present invention, standing waves occur in the vertical direction (in the direction of the center axis of the cylinder), as in the rectangular parallelepiped enclosure of the conventional device, but as described for the conventional device, the mounting position of the bass speaker is This can be taken as a countermeasure by determining the position of the node of the standing wave mode.

以上のように、本発明によれば、低音用スピー
カをエンクロージヤのバツフル平面に取付けて成
るスピーカ装置を、従来装置のように、エンクロ
ージヤ内に前後方向の定在波を励起させることな
く、したがつて、音圧特性の乱れが少なく、ひい
て、音質の劣化も少ないものとすることができ
る。 As described above, according to the present invention, a speaker device in which a bass speaker is attached to a butt-full plane of an enclosure can be used without exciting standing waves in the front-rear direction inside the enclosure, unlike conventional devices. Therefore, there is less disturbance in the sound pressure characteristics, and therefore less deterioration in sound quality.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は従来のスピーカ装置を示す斜視図、第
２図は第１図示のものの音圧周波数特性を示す
図、第３図ａ〜ｃは定在波周波数時の音圧と粒子
速度の、それぞれ、１次〜３次のモードを示す
図、第４図は本発明の一実施例を示し、ａは正面
図、ｂはａの−に沿つた水平横断面図、第５
図ａ〜ｈは円筒音場の音圧モードを示す図、第６
図ａ，ｂは、それぞれ、本発明の他の実施例を示
す図である。 １……エンクロージヤ、２……バツフル面、３
……低音用スピーカ、５……円筒面。 FIG. 1 is a perspective view showing a conventional speaker device, FIG. 2 is a diagram showing sound pressure frequency characteristics of the speaker device shown in FIG. 1, and FIGS. 3 a to c show sound pressure and particle velocity at standing wave frequencies. 4 shows an embodiment of the present invention, a is a front view, b is a horizontal cross-sectional view taken along - of a, and FIG.
Figures a to h are diagrams showing the sound pressure mode of a cylindrical sound field.
Figures a and b are diagrams showing other embodiments of the invention, respectively. 1...Enclosure, 2...Bullet surface, 3
...Bass speaker, 5...Cylindrical surface.

Claims (1)

【特許請求の範囲】 １ 低音用スピーカをエンクロージヤのバツフル
面に取付けて成るスピーカ装置において、エンク
ロージヤを、内部が、上下両端を閉止した円筒を
その中心軸を含む少なくとも一平面により二つに
切断した、その一方の形状をなすものとし、か
つ、低音用スピーカをエンクロージヤの上記円筒
としての中心軸上に取付けたことを特徴とするス
ピーカ装置。 ２ エンクロージヤの水平横断面が半円形である
ことを特徴とする特許請求の範囲第１項記載のス
ピーカ装置。 ３ 低音用スピーカの取付位置がエンクロージヤ
内の上下方向に生ずる定在波の音圧モードの節の
位置でもあることを特徴とする特許請求の範囲第
１項または第２項記載のスピーカ装置。[Scope of Claims] 1. A speaker device in which a bass speaker is attached to the butt-full surface of an enclosure, in which the enclosure is divided into two by at least one plane including the central axis of a cylinder whose interior is closed at both upper and lower ends. What is claimed is: 1. A speaker device having a cut-off shape, and having a bass speaker mounted on the central axis of the cylindrical enclosure. 2. The speaker device according to claim 1, wherein the horizontal cross section of the enclosure is semicircular. 3. The speaker device according to claim 1 or 2, wherein the mounting position of the bass speaker is also a node position of a sound pressure mode of a standing wave generated in the vertical direction within the enclosure.
JP7094383A 1983-04-22 1983-04-22 Speaker device Granted JPS59196691A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP7094383A JPS59196691A (en) 1983-04-22 1983-04-22 Speaker device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP7094383A JPS59196691A (en) 1983-04-22 1983-04-22 Speaker device

Publications (2)

Publication Number Publication Date
JPS59196691A JPS59196691A (en) 1984-11-08
JPS6351636B2 true JPS6351636B2 (en) 1988-10-14

Family

ID=13446085

Family Applications (1)

Application Number Title Priority Date Filing Date
JP7094383A Granted JPS59196691A (en) 1983-04-22 1983-04-22 Speaker device

Country Status (1)

Country Link
JP (1) JPS59196691A (en)

Also Published As

Publication number Publication date
JPS59196691A (en) 1984-11-08

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