JPS6264196A - Horn speaker - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention is intended to improve the sound quality depending on the listening position when creating a uniform sound field for a large number of listeners in indoor and outdoor sound reproduction such as halls, station premises, and grounds. The present invention relates to a horn speaker capable of reproducing high-fidelity bodhisattva sounds with no difference in clarity.

2. Description of the Related Art Conventional horns include radial horns, conical horns, and the like. The radial horn is designed so that the wavefront forms an arc in the horizontal plane, so this arc-shaped wavefront propagates concentrically inside the horn, so it radiates directly from the aperture without directivity. Although it has excellent directivity, it has the disadvantage that it is not good in the vertical direction. Also, conical horns have excellent directivity in the horizontal and vertical directions, but
The disadvantage is that the radiation impedance characteristics are disturbed.

FIGS. 8a and 8b show a conical horn disclosed in Japanese Patent Application Laid-Open No. 12724/1983. This horn has a straight sidewall curve and is a combination of two conical horns.

Problems to be Solved by the Invention However, the above-described conventional horn has the drawback of large disturbance in radiation impedance.

The wall shapes of representative horns, such as the exponential, conical, and Bessel horns, are shown in FIG. 9a, and their radiation impedance characteristics are shown in FIG. These horns are expressed as the general formula of the Bessel horn on the web site as shown below.

SM=SO(1+αx)″ SM: Cross-sectional area of the cut So Cross-sectional area of the throat α: Spreading coefficient .

As is clear from FIG. 9, as n becomes smaller, the disturbance in the radiation impedance increases, and the problem is that the disturbance in the radiation impedance of the conical horn becomes the largest.

In view of the above conventional problems, the present invention aims to suppress disturbances in radiation impedance and flatten frequency characteristics.

Means for Solving the Problems In order to achieve the above object, the present invention provides a horn consisting of four walls in which the target pointing angle in the horizontal direction (θH) and the target pointing angle in the vertical direction (θV) are in different relationships. Each wall curve of one opposing wall surface of the horn that faces each other, and each wall curve of the other opposing wall surface of the horn that extends from the opening on the central axis of the horn up to a distance of 12, It is expressed by the following formula, a ” a () (1+(L 1≧2), n2 (n2>''1) on the throat side, and the tangential angle of the horn aperture is 1.5θ to 2.00 when the target pointing angle is 2θ. and the change in cross-sectional area from the throat of the horn to the distance from the opening to 12 points is a straight shape from the throat to the opening, and the change in cross-sectional area is exponential within the straight shape. The structure is such that partition walls having such a shape are arranged in parallel and connected to one opposing wall surface of the horn.

Effects of the present invention With the above-described configuration, the sound pressure 1 distribution does not vary greatly depending on the frequency, the sound quality becomes uniform depending on the listening position, and the frequency characteristics are flat because there is little disturbance in the radiation impedance characteristics.

EXAMPLE An example of the present invention will be described below with reference to the drawings.

First, we performed a simulation of the directivity of a rectangular horn with a straight sidewall curve. This was done using the Wolb & Ma ter formula using an arcuate line sound source model in which the horn was driven with equal sound pressure and two equal phases at the opening of the horn, as shown in FIG.

PA However, Ra is the directivity coefficient of angle α, r is the radius of curvature, and d
is the length of the line sound source divided into (2m+1), and the results of calculations performed using the above formula are shown in FIGS. FIG. 6 shows a case where the tangential angle of the opening is changed, and FIG. 6 shows a case where the arc radius r is changed. From this result, it can be seen that in the low range, the aperture angle and the directivity angle match at a frequency of Ka #1, 89/sinθ. Furthermore, the directivity angle approaches the aperture angle at high frequencies. In order to make the directivity angle uniform, Ka
The directivity angle in the low range centered on 450/2θ is about θ/lo, but we hypothesized that the tangential angle of the horn opening, which is a directivity control factor in this band, is about βθ.

A horn was created based on this hypothesis and the results of actual measurements are shown in FIG.

As is clear from FIG. 7, in the Bessel horn, by setting the tangential angle of the aperture to approximately βθ, the directivity angle in the low range becomes θ, and the hypothesis has been verified.

In addition, the tangential angle of the horn opening is 1.5θ to 2.00,
As a result of making a horn and actually measuring it, it was confirmed that the directivity angle in the low range is θ. Then, we found that the best result was when we set ρθ.

The horn shape of a horn speaker in an embodiment of the present invention is shown in FIGS. 1a and 1b. FIG. 1 & shows the shape in the vertical direction, and FIG. 1 shows the shape in the horizontal direction.

The horn of this embodiment consists of four wall surfaces 1.2, 3.4 and a partition wall 6, and when the horizontal and vertical directivity angles are equal, the connection angle of the side walls at the horn opening is approximately -0. . Each side wall curve of the horn is expressed as a function of """ o ('10 αx), n ao Nisthroat dimension a: Dimension of the cross section at distance X from the throat α: Spreading coefficient (different between the n1 part and the n2 part) and the value of n is nl (n1≧2) on the opening side.
, n2 (n2>nl) on the throat side. Point A is determined by the flatness of the deviation of the directional characteristics.

On the other hand, if the horizontal directivity angle θH and the vertical directivity angle θ■ are different, the longer the directivity angle, the shorter the length. θ
If V〈θH, then the change in cross-sectional area from the throat to point B in the θH direction is a straight shape, and within that straight shape, a partition wall 6 of a shape such that the change in cross-sectional area is exponential is placed parallel to the wall surface. and connect it to the vertical upper and lower walls 1°2. Also, in the portion extending from point B to the opening side, the side wall curve changes from nl to n2 at point C. Note that point C is determined by the flatness of the deviation of the directivity angle characteristics.

The directivity characteristics of the horn speaker according to the present invention are shown in Fig. 2a and b.
Shown below. Furthermore, the radiation impedance and frequency characteristics are shown in FIGS. 3a and 3b. In Figures 3a and 3b, solid lines indicate the present invention;
The broken line indicates a conventional conical horn.

In this example, 2θy: 400.2θH = 9oO is selected, and within that range, the sound pressure distribution does not vary greatly depending on the frequency, does not vary greatly depending on the listening position, and the sound quality is uniform depending on the listening position. It shows that something is true. Furthermore, since there is little disturbance in the radiation impedance characteristics, this indicates that the frequency characteristics are flat.

In addition, as shown in Figure 7, the side wall shape from the 82 point distance from the opening on the central axis of the horn to the throat is straight, and the opposing wall surfaces are parallel, making it easy to manufacture the horn itself. Become.

By making the cross-sectional area change on the throat side different from the white wall line on the opening side in this way, the horn's radiation impedance changes in the cross-sectional area in the exponential and hi-bopolytsu shapes, which have less disturbance and load faster near the cutoff frequency. is applied, and the flatness of the sound pressure frequency characteristics is improved. Also,
Since the directivity is controlled, the sound pressure distribution does not vary greatly depending on the frequency, and the sound quality has the advantage of being uniform depending on the listening position.

Effects of the Invention As described above, the present invention has the advantage that the sound pressure distribution does not vary greatly depending on the frequency, the sound quality is uniform depending on the listening position, and the frequency characteristics are flat because there is little disturbance in the radiation impedance characteristics. It is something that you have.

Further, since the side wall shape is straight for a predetermined length from the horn opening, and the opposing wall surfaces are parallel, the horn itself can be manufactured easily.

[Brief explanation of the drawing]

Figures 1a and b are vertical and horizontal cross-sectional views of a horn speaker according to an embodiment of the present invention, Figures 2a and b are directional characteristic diagrams of the horn speaker, and Figures 3a and b are the same horn speaker. Radiation impedance characteristics and sound pressure frequency characteristics of
The figure shows a directivity angle characteristic diagram for the arcuate line sound source model shown in FIG. 4, FIGS. A horizontal sectional view and a vertical sectional view, FIG. 9a is a half sectional view of various horns, and FIG. 9 is a radiation impedance characteristic diagram of the same various horns. 1.2, 3.4... Wall surface, 6... Partition wall. Name of agent: Patent attorney Toshio Nakao and 1 other person
1 Fig. 2 Fig. 5 Fig. 711.1h: cst> Fig. 6 Fig. 1. Hono Cane (#, 0 Figure 8)

Claims (1)

[Claims] A horn comprising four walls in which the target pointing angle (θ_H) in the horizontal direction and the target pointing angle (θ_V) in the vertical direction are different from each other, and the horns are oriented toward each other. Each wall surface curve of one opposing wall surface that meets each other and each wall surface curve of the other opposing wall surface of the horn that extends from the opening to the distance l_2 on the central axis of the horn are expressed by the following formula, a=a_O( 1+αX)^n a_O: Dimension of throat a: Dimension of cross section at distance It is a combination of functions, where the tangential angle of the horn aperture is set to 1.5θ to 2.0θ when the target directivity angle is 2θ, and the cross section from the throat of the horn to the distance l_2 point from the aperture. The change in area is straight from the throat to the opening, and a partition wall having a shape such that the change in cross-sectional area is exponential is arranged in parallel within the straight shape, and on one opposing wall surface of the horn. A horn speaker characterized by being combined.