JPS5843331Y2 - Structure of cabinet for speakers etc. - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to the structure of a cabinet for a speaker, player, etc., which is designed to eliminate resonance.

In conventional cabinets for speakers, etc., as shown in FIG. 1, there is a particle board (also called a homogen board).

) An organic compound 3 such as vinyl chloride or a wood material 4 such as a so-called veneer was adhered to the surface of the material 1 via an adhesive 2.

Now, the propagation velocity of the vibration waves generated by the speaker's audio output within the medium of the cabinet tends to be low in a structure made of particle board and vinyl chloride bonded to it; When it comes to objects, the loss of vibrational energy applied to the material medium tends to be small.

An object of the present invention is to provide a structure for a cabinet such as a speaker that achieves resonance-free construction by joining media with different propagation velocities of vibration waves.

Generally, the transient characteristics of a resonant rod made of particle board with both ends free are as shown in FIG.

That is, Figure a shows the frequency response characteristics, and as is clear from the figure, the loss (attenuation degree) of vibration waves I/i is small in the low frequency region, and tends to increase as the frequency increases. It can be seen that resonance occurs at a specific frequency.

FIG. 2 is a diagram in which the characteristic root of the characteristic equation of the transfer function of the transient characteristic is plotted on a complex plane, and shows the same contents as FIG.

In fact, as shown in Figure 3, the transient characteristics of metallic materials show that the loss of vibration waves is large in the low frequency range, and tends to decrease as the frequency increases, as shown in Figure 2. It has the opposite characteristics to particle board, and it can be seen that it also resonates at a specific frequency.

Figure 3 shows characteristic roots plotted on a complex plane in the same way as Figure 2.

In this way, the transient response characteristics of a medium with a slow vibration wave propagation speed (for example, particle board) and a medium with a fast vibration wave propagation speed (such as metal) have opposite characteristics.

This invention has been developed based on the above facts,
One embodiment is shown in FIG.

Figure a shows an example of the structure of a cabinet in which a metal material 12 is bonded to one side of a particle board 10 via a viscoelastic body 11 such as double-sided adhesive tape; This is an example of the structure of a cabinet in which metal materials are joined via a metal material.

When media with different propagation speeds of vibration waves are joined in this way, the level of vibration energy decreases as shown in Figure 5, that is, the degree of attenuation increases, and the level of vibration energy remains constant, resulting in a non-resonant state ( Figure 5 a, b).

As shown in FIG. 5, a non-resonant state can be obtained most efficiently when the weights of the particle board and the metal material are approximately the same.

However, not only particle board but also organic compounds can generally be bonded to metal to eliminate resonance.

(Joining here means integrating using a viscoelastic material such as double-sided adhesive tape, excluding an adhesive.

) Actual measurement data is shown in Figs. 6 to 9.

In each case, a 20 mm 0-sheet particle board was used as a sample, and Figure 6 shows only the particle board.
Figures 7 to 9 are made of particle board, glass (plate thickness 5 mm), brass (1.5 mm), copper (1.5 mm).
This is the frequency response characteristic for each case in which 2 mm) are joined.

As is clear from these figures, in the case of only particle board (Figure 6), a resonance state appears at approximately a constant period, but when media with different propagation speeds of vibration waves are joined (
A non-resonant state is obtained in FIGS. 7 to 9).

According to the structure of the speaker cabinet of the present invention, the adhesive material such as a metal plate to be bonded to the cabinet made of organic material via an adhesive material is made of a high-quality metal material with a high propagation speed of vibration waves. At first glance, it seems technically contradictory to attach these materials, which are rigid and are generally considered to be easily vibrated, to the cabinet, but as is clear from the measurement results shown in the drawings. , the resonance between the cabinet constituent materials and the metal plate cancels each other out, making it possible to accurately eliminate resonance, and providing an excellent cabinet with a simple configuration.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view showing the structure of a conventional speaker cabinet, Figure 2 shows the transient characteristics of the particle board during vibration, Figure a shows the frequency response characteristics, and Figure 2 shows the transient characteristics of the particle board during vibration. Figure 3, which is a diagram plotting the characteristic plate of the transfer function on a complex plane, shows the transient characteristics in the case of metal materials, similar to Figure 2, and Figure 3a shows its frequency response characteristics. is a diagram in which the characteristic plate is plotted on a complex plane; FIG. 4 is a sectional view showing the structure of the cabinet according to the present invention;
Figure 5 shows the transient characteristics when media with different vibration wave propagation velocities are joined, and Figure a shows the frequency response characteristics.
This figure is a diagram in which the characteristic plate is plotted on a complex plane, and FIGS. 6 to 9 are diagrams showing actually measured data, respectively. 10...Particle board, 11...
- Viscoelastic body, 12... Metal material.

Claims (1)

[Scope of utility model registration request] A speaker cabinet made of an organic material such as particle board is made of a metal material with a high propagation speed of vibration waves, such as a copper plate, for the whole or -r part of one or both sides of the speaker cabinet.
A cabinet structure characterized in that a metal plate having a mass equal to the total mass of the cabinet constituent members is joined.