JPH0725839Y2 - Resonance box for soundboard percussion instrument - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resonance box of a percussion instrument that strikes a tone plate and produces a sound of a specific frequency.

[0002]

2. Description of the Related Art This type of sound plate percussion instrument has an opening formed on the upper surface of a rectangular parallelepiped hollow box body to combine air inside and outside the box, and a sound plate for producing a hammering sound is provided in the box body outside the opening. With the attached one, hit the sound board to resonate the tapping sound in the box body.
It is a well-known musical instrument having a structure for making it.

This percussion instrument can be said to be a direct application of the Helmholtz resonator, but the lower the tone due to its structure, the larger the resonance box must be in order to lower the resonance frequency. For example, in the conventional resonance box structure, 82.4 Hz (2
When trying to obtain a resonance frequency of 0E), the box body is
The width and height are also 270 × 600 × 350 (mm) (see FIG. 5B).

[0004]

The present invention has been made in view of the above-mentioned points. The problem is to reduce the size of the resonance box of a percussion instrument and to obtain resonance in the low frequency range with a particularly small volume. To be able to do so.

[0005]

In order to solve the above-mentioned problems, the present invention forms an opening 2 on one surface of a box body 1 and resonates the tapping sound of a sound plate 3 provided outside the opening in the box body 1. The soundboard percussion instrument is designed to have a throat 5 which is fitted into the opening 2 and whose inner end 4 projects into the box body to change the resonance frequency. It is a thing.

It has been found in the course of development of the present invention that the length of the throat 5 and the distance from the sound plate 3 change the resonance frequency. Therefore, the present invention also aims to change the resonance frequency by changing the length of the throat 5 or the distance between the throat 5 and the sound plate 3.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A description will be given below with reference to the drawings. As shown in FIGS. 1 to 3 or 6, the sound plate percussion instrument has a box-shaped box body 1. In each figure, 6 is a top plate,
An opening 2 having a required area is formed in a slender shape in the center thereof.

The sound plate 3 is arranged above the opening 2 and
It is attached to the upper surface plates 6 on both sides in the longitudinal direction at two positions via the left and right fulcrum mechanisms 10, and the pitch P between both fulcrums can be changed according to the frequency (FIG. 2).

The fulcrum mechanism 10 is provided in mounting holes 11 formed at fixed positions on both extensions of the opening 2, and a lower cushion 12 fixed to the upper surface plate 6 at the mounting hole positions and an upper cushion fixed to the upper portion thereof. 13, both cushions 1
It has fulcrum bolts 15 penetrating 2 and 13 and the sound plate 3 placed thereon, and erected via an insulator 14 fitted to the lower end of the mounting hole 11.

The fulcrum bolt 15 is provided with washers 16 and 17 for holding both upper and lower surfaces of the upper plate 6, and a spacer 18 consisting of a nut screwed with the bolt 15 on the upper washer 17.
Sleeve tube 2 made of rubber material, etc.
It is covered with 0. Therefore, the sound plate 3 comes into contact only with the uppermost cushion 19 provided between the bolt head 23, the upper cushion 13 and the sleeve tube 20.

The throat 5 is fitted and fixed in the opening 2, and its inner end 4 projects into the box body 1. The illustrated opening 2 is formed to be elongated in conformity with the oblong shape (of the top plate) of the box body 1, and the throat 5 also has an elongated cross-sectional shape that is closely fitted thereto. However, the shape of the opening that gives this area S can be changed according to the shape of the box body 1.

With such a structure in which the throat 5 is fitted and attached to the opening 2, it becomes easy to adjust the gap G between the upper end portion 7 and the lower surface of the sound plate 3, and the gap G can be adjusted by this adjustment. It was found that the resonance frequency can be increased by increasing the value. If you change the throat 5 to a different length,
Even if the volume of the box body 1 is the same, the resonance frequency can be changed. Therefore, it is possible to reduce the size of the box body 1.

The opening area S of the throat 5 is one factor that gives the resonance frequency fo according to the Helmholtz resonance theory. The resonance frequency fo is given by the following equation.

Fo = c / 2π√ (S / Vl) where c is the speed of sound, V is the volume of the resonance box body 1, and 1 is the length of the throat 5.

If the resonance frequency is set to 82.4 Hz as shown in FIG. 5B, the length, width and height of the resonance box according to the present invention are 220 × 600 × 295 (m).
m), and the throat opening area S is 14925 at this time.
mm ² (theoretical value 10747mm ²⁾ is. The volume ratio between the conventional resonance box and the resonance box according to the present invention is about 68.7%, which means that the size is reduced by 30% or more.

By changing the length 1 of the throat 5 and the shape of the sound plate 3, different resonance frequencies can be dealt with. For sounds above 20E, the relationship is as shown in the following table. In the table, P is the pitch between fulcrums, and this value is usually set to 60% of the length of the sound plate 3.

[0017]

[Table 1] In each drawing, 21 is a gap between the head of the fulcrum bolt and the sound plate 3, 2
Reference numeral 2 is a cushioning leg that supports the box body 1, and the cushions 13 and 19
It consists of felts as well.

[0018]

Since the present invention is constructed and operates as described above, the throat 5 is provided at the opening of the resonance box and the lower end 4 of the throat 5 is projected into the box body 1. Significantly reduces the volume of the resonance box that resonates with
Resonance in the low frequency range can be obtained with a small volume, and the effect of miniaturizing the sound plate percussion instrument is achieved. Also, the miniaturization of the resonance box body 1 does not impair the generation of powerful resonance sound,
There are many advantages such as maintaining good acoustic effects. Furthermore, the resonance frequency can be changed without changing the size of the box body 1 by changing the length of the throat 5 or the distance between the throat 5 and the sound plate. Exerts the characteristic of facilitating.

[Brief description of drawings]

FIG. 1 is a partially omitted plan view according to an embodiment of a percussion instrument of the present invention.

FIG. 2 is a partially cutaway front view of the same.

FIG. 3 is a side view of the same.

FIG. 4 is a sectional view of the fulcrum structure of the above.

FIG. 5A is an outline view of a resonance box according to the present invention. (B) The outline figure of the conventional resonance box concerning the same frequency as (a).

Claims (3)

[Scope of utility model registration request] 1. A sound plate percussion instrument in which an opening 2 is formed on one surface of a box body 1 and the sound of a sound plate 3 provided outside the opening is made to resonate in the box body 1. Fit in,
A resonance box for a percussion instrument, characterized in that the box body (1) is provided with a throat (5) whose inner end (4) projects into the box body to change the resonance frequency. 2. The throat 5 is fitted into the opening 2 so as to be attached, whereby a gap G between the upper end portion 7 of the throat 5 and the lower surface of the sound plate 3 can be adjusted, and the height of the resonance frequency can be adjusted by adjusting the gap G. The resonance box for a percussion instrument of claim 1, wherein the resonance box is configured to be adjustable. 3. The resonance box for a musical instrument as claimed in claim 1, wherein the resonance frequency is changed by changing the length of the throat 5 with respect to the box body 1 having the same volume.