JPH084355B2 - Speaker - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speaker for HiFi reproduction in a room such as a listening room and a small hall.

2. Description of the Related Art In recent years, from the viewpoint of space saving, a wall-mounted type or a built-in type thin speaker is being developed for a speaker used in a listening room, a general household or the like.
As such a thin speaker, a back open type speaker using a large-area diaphragm has long been known.
However, in the case of the open rear speaker, when the sound is played close to the wall surface in the room, the out-of-phase sound from the back becomes noticeable, and the low-frequency level drops, making it difficult to reproduce powerful bass. Becomes

On the other hand, in recent years, there has been proposed a speaker that uses both a closed type speaker and a rear open type speaker. That is, it is a thin speaker in which a part of the large-area diaphragm is of a rear open type and the remaining part is of a closed type. The aim of such an eclectic speaker is to realize a necessary sound pressure level by microvibration even at the time of low frequency reproduction by reducing the size of the diaphragm so that harmonic distortion can be reduced. Compared with the case where all parts are closed, the rigidity of the closed space can be reduced and the low frequency reproduction limit can be expanded, and the other part of the diaphragm can be opened and the open hole on the back of the speaker can be used. By appropriately deciding the size and position of, the low-range reproduction limit can be expanded by placing a certain amount of additional mass on the diaphragm, and the path of the wraparound sound from the back side can be set large, so It is possible to reduce the effect to some extent.

Hereinafter, the above-described closed open eclectic type thin speaker will be described with reference to the drawings.

FIG. 2 is a front view showing the above-described conventional closed open eclectic type thin speaker. Further, FIG. 3 is A- of FIG.
It is an A'cross section figure. In FIGS. 2 and 3, 1 is a speaker box, 2 is an edge, 3 is a diaphragm having a large area, and the diaphragm 3 is located at a closed portion 7 and a central portion by a partition wall 4 and an inner edge 11. It is divided into an open part 5 and an open part 5. Reference numeral 9 denotes a closed space formed by the closed portion 7 of the vibration plate 3, which is an element that acts as stiffness during low frequency reproduction. Reference numeral 10 denotes an open space formed by the open portion 5 of the diaphragm 3, which is located near the center of the back side of the diaphragm 3 and communicates with the outside air through an open hole 6 provided in the back surface of the speaker box 1. There is. Further, by adjusting the opening area of the open hole 6, an appropriate additional mass is added to the open portion 5 of the diaphragm 3. Reference numeral 8 denotes a voice coil arranged at a driving position of the diaphragm 3, which is arranged at a node of natural resonance of the rectangular diaphragm 3.

In the thin speaker as described above, by adjusting the ratio between the closed system portion 7 and the open system portion 5 of the large-area diaphragm and the opening area of the open hole 6, f _0, that is, the stiffness and the added mass of the speaker system. , And the reproduction efficiency can be realized to some extent. Further, by providing the position of the open hole 6 near the center of the back surface of the speaker box 1, it is possible to lengthen the path of the wraparound sound from the back surface of the speaker box, which causes deterioration of low-frequency reproduction due to interference of antiphase sounds. Can be reduced.

Problems to be Solved by the Invention However, in the above example, the open portion 5 of the diaphragm 3 is
Are located near the center of the diaphragm 3 because of the position of the open hole 6. Therefore, when attention is paid to the longitudinal direction of the diaphragm 3, additional mass is added to the vicinity of the center, and considerably large stiffness acts on both sides of the diaphragm 3 due to the closed space, which is structurally unbalanced. Therefore, the longitudinal split resonance of the diaphragm easily occurs. Further, even if the voice coil 8 is located at the node of the split resonance, it is difficult to realize a complete piston motion, and a bending vibration mode is likely to occur due to uneven distribution of the reactance component and the inductance component. Had.

In view of the above problems, the present invention provides a speaker that can reduce structural imbalance in the longitudinal direction of the diaphragm and realize good sound pressure frequency characteristics by node drive.

Means for Solving the Problems In order to solve the above problems, the speaker of the present invention comprises:
The opening method part of the substantially rectangular diaphragm having a large area is arranged in a rectangular shape along the longitudinal direction of the diaphragm, and the aspect ratio a '/ b' of the opening method part is set to the aspect ratio a / b of the diaphragm itself.
It is larger than (a> b).

Operation The present invention has a structure in which the added mass added by the open method and the stiffness acting by the closed method are uniformly distributed in the longitudinal direction of the rectangular diaphragm where the split resonance is most likely to occur, by the above-mentioned configuration. It is possible to realize good piston motion over a wide band together with the nodal drive method of the diaphragm, eliminating the physical imbalance.

Example Hereinafter, a speaker of an example of the present invention will be described with reference to the drawings.

FIG. 1 is a front view showing a speaker according to an embodiment of the present invention. In FIG. 1, a speaker box 1, an edge 2, a diaphragm 3, a partition wall 4, an opening method part 5 and a sealing method part 7 of the diaphragm 3, an opening hole 6 provided on the back surface of the speaker box 1, a diaphragm. The voice coil 8 provided at the driving position 3 is the same as that shown in FIGS. Also on the drawing a, b
Is the vertical and horizontal dimensions of the diaphragm 3, and when a> b, a is the longitudinal direction. Reference characters a'and b'represent the vertical and horizontal dimensions of the opening method portion 5 of the diaphragm 3 (a '>b'), which are substantially rectangular. Further, in this embodiment, the diaphragm 3 and the opening method portion 5 are aligned in the longitudinal direction, the target axes are aligned with each other, and the aspect ratio of the opening method portion 5 is larger than that of the diaphragm 3, that is, a '. / b ′
> A / b.

In the loudspeaker configured as described above, as the mass acting on the diaphragm 3, in addition to the mass of the diaphragm 3 itself, the additional mass is placed in the region of the open system portion 5. In addition to the stiffness of the support system, a stiffness (significantly larger than that of the support system) caused by the closed space is generated in the region of the sealing system portion 7 as the stiffness to act. Considering the longitudinal direction of the diaphragm 3 where split resonance is most likely to occur, that is, the XX direction in FIG. 1, the distribution of these structural elements is considered to be substantially uniform at least in the middle and low range reproduction.
Therefore, by using the joint drive method using a plurality of voice coils 8 together, good piston motion of the diaphragm 3 can be realized over a relatively wide band, and sound pressure frequency characteristics with few peak dips can be realized. .

In FIG. 1, the number of the open holes 6 provided on the back surface of the speaker box 1 is one, but a plurality of open holes may be provided.

EFFECTS OF THE INVENTION The present invention makes a part of a flat plate-shaped diaphragm having a substantially rectangular shape an open system and makes an area constituting the open system a substantially rectangular shape, and sets the aspect ratio to be equal to or greater than the aspect ratio of the diaphragm itself, and sets the longitudinal direction to By arranging them in alignment, it is possible to realize a good piston motion of the diaphragm over a relatively wide band and a speaker capable of obtaining a sound pressure frequency characteristic with few peak dips.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view showing a speaker in an embodiment of the present invention, FIG. 2 is a front view showing a conventional speaker, and FIG. 3 is a sectional view of the same. 1 ... speaker box, 2 ... edge, 3 ... vibration plate, 4 ... intermediate partition wall, 5 ... vibration plate opening method part,
6 ... Open hole, 7 ... Diaphragm sealing part, 8 ... Voice coil, 9 ... Sealed space, 10 ... Open space, 11 ...
Inner edge.

Front Page Continuation (72) Inventor Katsumasa Sato 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Kazuei Sato 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (72) Inventor Hiroyuki Takewa 1006, Kadoma, Kadoma-shi, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor, Shuji Saeki Osaka, Kadoma 1006 Kadoma, Matsushita Electric Industrial Co., Ltd. (72) Inventor, Seiichi Ishikawa Osaka 1006 Kadoma, Kadoma-shi, Matsushita Electric Industrial Co., Ltd. (72) Inventor, Yoichi Kimura, 1006 Kadoma, Kadoma, Osaka Prefecture (72) Inventor, Shuichi Obata, 1006, Kadoma, Kadoma, Osaka Matsushita Electric Sangyo Co., Ltd. (56) Reference JP-A-63-77299 (JP, A)

Claims (1)

[Claims] 1. A structure in which a flat plate diaphragm having a substantially rectangular shape is partly opened and the remaining part is a closed part, and a region constituting the open part of the flat plate diaphragm is made substantially rectangular and its length and width are defined. A loudspeaker characterized in that the ratio is set to an aspect ratio of the diaphragm itself of a / b (a> b) or more, and the diaphragm is arranged substantially symmetrically with respect to the flat diaphragm.