JPH028476Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention relates to an improvement of the vibration system of a dome-shaped speaker in the field of electroacoustic equipment.

[Conventional technology]

A dome-shaped speaker generally has a magnet 31, a center pole 32, a front plate 33, and a back plate 34, as shown in FIG.
The edge 37 supports the diaphragm so that the voice coil 36 fixed to the outer periphery of the diaphragm 35 is positioned in the magnetic gap formed by the center pole 32 and the front plate 33 of the magnetic circuit. The diaphragm 35 is driven through electric current to emit sound waves.

The diaphragm 35 is usually made of a lightweight and highly rigid material such as duralumin in order to make the divided vibration frequency as high as possible and improve the frequency characteristics.

Another configuration of the dome-shaped speaker is that the diaphragm is made of a soft material with extremely high internal loss.
There are so-called soft dome speakers.

[Problems to be solved]

In the conventional example described above, the diaphragm using a high-rigidity material has low mechanical internal loss as a material, so at frequencies higher than the piston vibration range,
The vibration energy transmitted from the periphery of the diaphragm and the vibration energy reflected at the center of the diaphragm interfere with each other, causing vibration nodes near the outer periphery of the diaphragm due to so-called anti-resonance. Since the vibration phase of the diaphragm outside and inside this vibration node is opposite to each other, the frequency of the anti-resonance is
A dip occurs in the frequency characteristics in _FR .
Furthermore, a peak occurred at the subsequent high-frequency resonance frequency _FH , resulting in deterioration of frequency characteristics and transient characteristics, which impaired the sense of hearing.

In addition, in the latter type of soft dome speaker, the internal loss of the diaphragm is extremely large, so resonance and anti-resonance are unlikely to occur, but the diaphragm has a large mass and it is difficult to transmit vibration energy, so the conversion efficiency as a speaker is extremely low. It was hot.

[Purpose of invention]

The present invention eliminates the drawbacks of the conventional example described above and uses an improved vibration system to prevent anti-resonance from occurring.
The purpose is to obtain a dome-shaped speaker with good frequency characteristics and efficiency.

[Means for solving problems]

In order to achieve the above object, the vibration system of the dome-shaped speaker according to the present invention extends the inner peripheral part of the edge inward with approximately the same curvature as the diaphragm, and the extended part has a diameter smaller than that of the voice coil. A dome-shaped diaphragm is glued, and one or more small holes are drilled in the extension of the edge outside the diaphragm so that the stiffness of this part is uneven, and the voice coil is Like the speaker, it has a structure that is glued to the bottom surface of the edge.

[Effect]

In the vibration system having the above configuration, the rigidity of the edge extension that supports the diaphragm is non-uniform over the entire circumference due to the small holes drilled in the edge extension that supports the diaphragm. Since the stiffness of the outer periphery of the diaphragm differs along the circumferential direction, significant anti-resonance and resonance in F _R and F _H as in the conventional example are dispersed, and the resulting frequency characteristics are The dips and peaks of the sound disappear, resulting in a flat frequency characteristic, and at the same time, the significant resonance disappears, resulting in good transient characteristics, resulting in a marked improvement in the reproduced sound quality.
Furthermore, since the voice coil bobbin is not directly connected to the diaphragm, the stiffness of the extension acts as a high-cut filter, and has the effect of cutting off unnecessary high frequencies.

〔Example〕

The vibration system of the dome-shaped speaker according to the present invention will be explained in detail with reference to FIGS. 1a, b to 2.

The voice coil bobbin 2 is finished in a cylindrical shape using the same material as the conventional one, and the voice coil 3 is wound around the lower end.

The diaphragm 1 is made of metal, paper impregnated with a hard excipient,
It is made of a lightweight, highly rigid material such as cloth or synthetic resin reinforced with a highly rigid filler, and its diameter is smaller than that of the voice coil bobbin 2.

The edge 4 is made of the same material as the diaphragm 1 or a soft, high internal loss material suitable for the edge. Extension part 41
is integrally formed, the above-mentioned diaphragm 1 is adhered to the extension part 41, and one or more small holes 42 are bored in the edge 4 extension part 41 outside the diaphragm, and the extension part 41 is Make sure that the stiffness is uneven in places.

A voice coil bobbin 2 with a voice coil 3 wound around its lower end is adhered to the lower surface of the edge 4, and the driving force from the voice coil 3 is transmitted through the voice coil bobbin 2 and is applied to the diaphragm 1 via the extension 41 of the edge 4. transmitted to the outer periphery.

A small hole 42 bored in this edge 4 extension 41
The size is such that it falls within the range of the extension outside the diaphragm, and the radial dimension d ranges from a minimum gap of just a cut to about 50% of the inner radius of the edge, and the width. W is 3 to 50 of the entire inner circumference of edge 4
%, and one or more locations (four locations in the illustrated example), or approximately six locations, give better results according to experimental results.

In addition, as another embodiment of the present invention, a structure in which a viscoelastic substance 5 such as rubber is filled or adhered to the surrounding area including the small hole 42 described above has the same effect as the present invention. Furthermore, it has the effect of preventing air from flowing in and out of the rear surface of the diaphragm 1, thereby eliminating a drop in efficiency, and also damping the outer peripheral portion of the diaphragm 1, which is in a free vibration state, to further improve the transient characteristics. (Second
The figure shows a state in which a viscoelastic body is attached. ) [Effects] Figure 4 shows the frequency characteristics of the dome-shaped speaker according to the present invention in comparison with a conventional example.

The solid line shows the characteristics of the dome-shaped speaker of the present invention, and the dotted line shows the characteristics of the conventional example.

In the conventional example, there are large peaks and dips at approximately 20KHz to 30KHz that are thought to be caused by resonance and anti-resonance, but in the present invention, these peaks and dips are dispersed and disappear, and the frequency characteristics are flat. Therefore, it is clear that the configuration of the vibration system according to the present invention is extremely effective in improving the frequency characteristics of a dome-shaped speaker.

In addition, since the diaphragm is mainly made of hard material and is lighter than a soft dome diaphragm, there is no drop in efficiency, resulting in a dome-shaped speaker with excellent frequency characteristics and transient characteristics not seen in conventional speakers. It is something that can be done.

[Brief explanation of the drawing]

Figures 1a, b, and 2 are front views, sectional views, and half sectional views of the vibration system of the dome-shaped speaker of the present invention, Figure 3 is a sectional view of a general dome-shaped speaker, and Figure 4 is It is a frequency characteristic diagram. 1 is a diaphragm, 2 is a voice coil bobbin, 3 is a voice coil, 4 is an edge, 41 is an extension part, 42 is a small hole, and 5 is a viscoelastic material.

Claims (1)

[Claims for Utility Model Registration] 1 Consists of a dome-shaped diaphragm 1, a voice coil bobbin 2, a voice coil 3 wound around the voice coil bobbin 2, and an edge 4 bonded to the upper end of the voice coil bobbin 2. In a dome-shaped speaker having a vibration system, an extension part 41 having approximately the same curvature as the diaphragm 1 is formed on the inner peripheral part of the edge 4, one or more small holes 42 are bored in the extension part 41, and a voice coil is formed. 1. A dome-shaped speaker characterized by having a vibration system configured such that a diaphragm 1 having a diameter smaller than 3 is attached to the extension part 41. 2. The dome speaker according to claim 1, wherein the small hole 42 is closed by filling, coating, or pasting the viscoelastic substance 5.