JPH06133385A - Horn for speaker - Google Patents

Abstract

PURPOSE:To realize a uniform sound pressure distribution by selecting a cross section of the horn to be a curve in a specific elliptic function so as to prevent the reduction in the sound pressure in an oblique direction thereby reducing a change in the sound pressure distribution with respect to frequencies. CONSTITUTION:The cross sectional shape in parallel with a throat cross section of the horn 20 at a distance (x) from the throat is a shape expressed in an elliptic function with a horizontal axis whose length is y1=g(x) as a function of (x) and with a vertical axis whose length is y2=h(x) as a function of (x). In the formula, y1 is the length of the horizontal axis of the elliptic cross section, y21 is the length of the vertical axis of the elliptic cross section, X, Y are parametrs representing the locus of the cross section and the relation of 2<=p<=10 is in existence. That is, the side wall in the oblique direction is changed continuously from a horizontal function g(x) till the vertical function h(x) and the directivity in the oblique direction is controlled by selecting the elliptic function for the cross section of the horn. Furthermore, since no, corner is provided, a sound wave is delivered to a wall face in every direction and a uniform sound pressure distribution is expressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a horn used for a horn speaker.

[0002]

2. Description of the Related Art In recent years, as a horn type speaker, a constant directivity horn speaker has been proposed which performs uniform directivity control over a wide frequency range. By limiting the service area, this constant directional horn reduces the disturbance of frequency characteristics at the listening point caused by mutual interference when using a plurality of speakers for loudspeaker, and also the wall surface of a building. It has the effect of reducing the reflected waves from. Further, there is an effect that a uniform sound pressure distribution and a flat frequency characteristic can be realized in the service area.

This horn has a quadrangular pyramidal sound hole consisting of two pairs of wall surfaces facing each other, and the wall surface is a horizontal side wall function designed to keep the directivity of sound waves constant over a wide frequency range. The curved surface follows g (x) and the vertical sidewall function h (x). The opening angle of this function is designed to be independent in the horizontal and vertical directions, and this allows the horizontal and vertical directivity angles to be freely controlled.

The following is a diagram of these constant directivity horns.
It will be described in detail with reference to the surface. Fig. 6 shows the conventional constant orientation
Fig. 7 is a front view of the sex horn, and Fig. 8 (a) is its front view.
Is a horizontal sectional view, and FIG. 6B is a vertical sectional view thereof. Figure
As shown in FIG. 6, curved surfaces 11 and 12, curved surfaces 13 and 14,
It is composed of two pairs of curved surfaces facing each other and has a square pyramidal sound hole.
ing. This is because the directivity in one direction of the horn is
There is a property that depends on the side wall function.
This is for directivity control in the horizontal and vertical directions. This
The curved surface of, for example, Japanese Patent Laid-Open No. 59-20238,
In JP-A-62-28920, the distance from the opening is 1₂
From the to the aperture, the horizontal function (Equation 4) and the vertical function (Equation 4)
5), and the value of n is calculated from the points 5 and 5'in FIG.
N on the opening side ₁(N₁≧ 2), n on the throat side₂(N₂>
n₁) Is a combined form of the function, and the target directivity angle is 2θ
When the horn opening tangent angle is 1.5θ ~ 2.0θ
It is set.

[0005]

[Equation 4]

[0006]

[Equation 5]

Further, between the point at a distance l ₂ from the opening and the throat (that is, l ₁ -l ₂ in FIG. 8A), the vertical function is expressed by (Equation 5), and the value of n is Figure 8 (b)
N ₃ (n ₃ ≧ 2) on the opening side and n ₄ (n ₄ > n ₃ ) on the throat side with respect to points 9 and 9 ′. In the conventional horn shown in FIG. 6, in the horizontal section 15 and the vertical section 16, the distance relationship between the central axis and each side wall is a horizontal function g.
Since (x) and the vertical function h (x) are followed, there is an advantage that uniform directional characteristics can be obtained regardless of frequency when the directional characteristics are measured in the horizontal section 15 and the vertical section 16.

[0008]

However, in the horn having the square-shaped sound hole, the distance relationship between the central axis and the wall surface is g (x), h in the cross section in the oblique direction as shown by the dotted line 17 in FIG.
It is significantly different from the function defined by (x), and the target directivity angle is different between the horizontal side wall and the vertical side wall, so that the directivity changes sharply near the corner. Further, while the wavefront has a property of advancing while becoming spherical, such a horn has a drawback that reflection occurs in this direction because it has a corner. Therefore, as shown in FIG. 5, when the sound pressure distribution on the surface 10 parallel to the opening surface of the horn is examined, the sound pressure in the oblique direction is low as shown in FIG. 9, and the sound pressure distribution is constant depending on the frequency. It had the drawback of not doing it.

The present invention prevents the sound pressure from decreasing in the diagonal direction of the conventional horn, reduces the change in the sound pressure distribution due to the frequency, and realizes a uniform sound pressure distribution.

[0010]

To achieve this object, the cross section of the horn of the present invention has a horizontal function g (x) in the conventional horn as a horizontal axis and a vertical function h (x) as a vertical axis. The elliptic function (Equation 6)

[0011]

[Equation 6]

[0012]

In the elliptic section horn of the present invention, the horizontal function and the vertical function are designed by the same design method as that of the conventional constant directivity horn shown in FIG. Changes continuously from the horizontal function g (x) to the vertical function h (x), and it is possible to control the directivity even in an oblique direction. Further, since there is no corner portion, the sound wave spreads to the wall surface in any direction, and the reflection seen at the corner portion does not occur.
Therefore, it is possible to prevent the sound pressure from decreasing in an oblique direction and to realize a uniform sound pressure distribution.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention is shown in FIG. In this embodiment, the horizontal target directivity angle is θh, the vertical target directivity angle is θv, and θh> θv. FIG. 1 is a perspective view of a horn 20 according to an embodiment of the present invention, and FIG. 2 is a front view of an inner wall of the horn. In addition, the side wall function of the horn section taken along the horizontal plane 1 in FIG. 1 is represented by the solid lines 3 and 4 in FIG.
The side wall function of the horn cross section cut along the vertical plane 2 is shown in FIG.
Are solid lines 7 and 8. As is clear from comparison between FIGS. 3 (a) and 3 (b) and FIGS. 8 (a) and 8 (b), the horn of this embodiment has a horizontal section and a vertical section which are completely different from those of the conventional horn. It is the same, and is characterized in that the cross section parallel to the opening is different. In FIG. 3A, the opening tangent angle in the horizontal direction is (Equation 7).

[0014]

[Equation 7]

The horizontal function is represented by (Equation 4). Here, the value of n is n ₁ (n ₁ ≧ 2) on the opening side and n ₂ (n ₂ > n ₁ ) on the throat side with respect to points 5 and 5 ′ in FIG. Point 5 is determined so that the frequency vs. directivity angle characteristics shown in FIG. 10 are most flat. In addition, in FIG. 3B, the opening tangent angle in the vertical direction is (Equation 8).

[0016]

[Equation 8]

The side wall function of the vertical section is expressed by (Equation 5), and the value of n is n on the opening side with respect to points 9 and 9'in FIG. 3 (b).
₃ (n ₃ ≧ 2) and n ₄ (n ₄ > n ₃ ) on the throat side.
At this time, points 9 and 9'are also determined by the same method as in designing the horizontal function. Since the horizontal directivity angle is larger than the vertical direction, the opening angle of the side wall function is large and the horn length is short. As shown in FIG. 3, when the vertical horn length is l ₁ and the horizontal horn length is l ₂ , l
₁ > l ₂ . From the opening to the portion of l ₂ to the throat, the horizontal function is a curve whose cross-sectional area change becomes exponential. P in (Equation 6) is 2 ≦ p
It is a real number such that ≦ 10, and the sound pressure distribution realized by the horn of the present invention shown in FIG. As shown in FIG. 5, when the sound pressure distribution on the surface 10 parallel to the opening surface of the horn is examined, the sound pressure distribution realized by the horn of the present invention shown in FIG. It can be seen that the above-mentioned improvement is made in comparison with the sound pressure distribution by the constant directivity horn.

[0018]

As described above, according to the present invention, it is possible to obtain a uniform sound pressure distribution in which the sound pressure does not decrease in an oblique direction as compared with the conventional horn and the sound pressure distribution does not change depending on the frequency. Becomes

[Brief description of drawings]

FIG. 1 is a perspective view of a horn according to an embodiment of the present invention.

FIG. 2 is a front view of the inner wall of the horn shown in FIG.

3A is a horizontal sectional view of the horn shown in FIG. 1, and FIG. 3B is a vertical sectional view of the horn shown in FIG.

FIG. 4 is a sound pressure distribution diagram of the horn in the embodiment of the present invention.

FIG. 5 is an explanatory diagram of a method for measuring sound pressure distribution.

FIG. 6 is a perspective view of a conventional horn.

FIG. 7 is a front view of a conventional horn.

8A is a horizontal sectional view of the conventional horn shown in FIG. 6, and FIG. 8B is a vertical sectional view of the conventional horn shown in FIG.

FIG. 9 is a sound pressure distribution diagram of a conventional horn.

FIG. 10 is a horizontal frequency vs. directional angle characteristic diagram of a conventional horn.

[Explanation of symbols]

 1 horizontal plane 2 vertical plane 3,4 horn horizontal function 6 horizontal function coupling point 7,8 horn vertical function 9,9 'vertical function coupling point 10 surface for measuring sound pressure distribution 11, 12, 13, 14 horn Side wall 15 Horizontal surface 16 Vertical surface 17 Diagonal surface 20 Horn

Claims (2)

[Claims] 1. The cross-sectional shape parallel to the horn throat cross section and at a distance x from the throat is expressed as a function of x.
Elliptic function with a horizontal axis of length ₁ = g (x) and a vertical axis of length y ₂ = h (x) expressed as a function of x A speaker horn having a shape represented by. 2. A horizontal function g (x) and a vertical function h (x) from the distance l ₂ from the opening of the horn to the opening are as follows: [Equation 3] And the value of n is n ₁ (n ₁ ≧
2), a combination of functions in which n ₂ (n ₂ > n ₁ ) on the throat side, and the distance l ₂ from the throat to the opening
2. The speaker horn according to claim 1, wherein the vertical function h (x) is expressed by (Equation 3).