JPH09139993A - Horn for speaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the lowering of the sound pressure in an oblique direction, to obtain an almost rectangle-shaped sound pressure distribution and to reduce the change of the sound distribution according to frequencies. SOLUTION: The cross section 5 parallel to a throat has a closed spline shape passing 8 points and the 8 points are the points 8 and 12 on a vertical cross section 2, the points 6 and 10 on a horizontal cross section 1 and the points 7, 9, 11 and 13 on oblique cross sections 3 and 4. The angle a of the horizontal cross section 1 and the oblique cross sections 3 and 4 and an oblique target directing angle are calculated from a horizontal target directing angle and a vertical target directing angle. Each of the cross sections of a horizontal direction, a vertical direction and an oblique direction has the coupled shaped of the curves having two different average opening angles. The short curve is moved in parallel to an opening side so that the opening parts may be matched, and the horn of the shape coupling a straight line or the curve is composed on the throat side. As a result, a sound pressure distribution is improved.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Recently, in this type of speaker horn,
There is provided a constant directivity horn that performs uniform directivity control over a wide frequency range. This constant directivity horn controls directivity in the horizontal direction and the vertical direction, and has a characteristic that a uniform sound field is obtained inside the directivity angle and sound pressure does not easily leak outside the directivity angle. Therefore, there is an effect that the mutual interference when the sound is amplified by using a plurality of horns and the reflected wave from the wall surface of the building are reduced, and a flat frequency characteristic is obtained at the listening point. Such a speaker horn has a quadrangular pyramidal sound hole composed of two pairs of wall surfaces facing each other, and the wall surface is a curved surface defined by a function that makes the directivity of sound waves constant over a wide frequency range. It has become. This function is designed to be independent in the horizontal direction and the vertical direction, so that the directivity in the horizontal direction and the directivity in the vertical direction are separately controlled.

Hereinafter, this constant directivity horn will be described in detail with reference to the drawings. 7 is a perspective view of a conventional constant directivity horn, FIG. 8 is a front view thereof, FIG. 9 (a) is a cross-sectional view of a horizontal cross section 21 thereof, and FIG. 9 (b) is a cross section of a diagonal cross section 26 thereof. The same drawing (c) is a sectional view of the vertical section 20. As shown in FIG. 7, this constant directivity horn has a quadrangular pyramid-shaped sound hole constituted by two sets of different curved surfaces, that is, curved surfaces 22 and 23 and curved surfaces 24 and 25 that face each other.
This is because the directional characteristics of the horn in the horizontal direction depend on the curve function of the horizontal section, and the directivity in the vertical direction depends on the curve function of the vertical section. This is because sex control is performed separately. This curved surface has a target directivity angle of 2θ _h in the horizontal direction and a target directivity angle of 2 in the vertical direction in Japanese Patent Publication No. 50-20238, for example.
When θ _v and θ _h > θ _v , the vertical cross section is expressed by the equation (5), and the value of n is n ₃ (n ₃ ≧ 2 on the opening side from 30, 30 ′ in FIG. 9C). ), N on the throat side
₄ (n ₄ > n ₃ ) and the tangent angle at the horn opening is 1.5θ _{v to} 2θ _v . In the horizontal cross-section of FIG. 9 (a), in between points and the opening of the distance 1 ₂ from the opening is represented by the formula (5), at the opening side of the 27, 27 'n ₁ (n ₁ ≧ 2),
In the throat side is _{n 2 (n 2 ≧ n 1} ), the tangent angle at the horn aperture is 1.5θ _v ~2θ _v, Expo change in sectional area of the horn is in between the distances 1 ₂ from the throat and the opening It is a curved line that makes it a natural one. y = a ₀ (1 + γx) ⁿ (5) a ₀ : throat radius γ: spread coefficient x: distance from throat n: coefficient

As described above, in the above-mentioned conventional horn,
As shown in FIG. 7, in the horizontal section 21 and the vertical section 20, the distance relationship between the central axis and the side wall is a curve in which the opening ratio smoothly gradually increases from the throat toward the opening, and the horizontal directivity and the vertical directivity are wide. It had the advantage of being constant over the frequency range.

[0005]

However, in the above-mentioned conventional speaker horn, in designing a sound field such as a hall or a stadium, as shown in FIG. 6, a plane 19 parallel to the horn opening surface is used. The sound pressure distribution is ideally a rectangular sound pressure distribution. However, in a horn with a square sound hole,
A cross section in an oblique direction such as 26 in FIG. 8 is not considered and the directivity is not controlled. FIG. 9B is a cross-sectional view of the horn shown in FIG. 8 in the direction of 26, which has inflection points 28 and 29. Therefore, when the sound pressure distribution on the surface 19 parallel to the opening surface shown in FIG. 6 is examined, FIG.
As shown in (b) and (c), there is a problem that the sound pressure in the oblique direction is low and the sound pressure distribution differs depending on the frequency.

The present invention solves the above-described problem in the conventional speaker horn, and prevents the sound pressure from decreasing in the diagonal direction of the horn to realize a sound pressure distribution close to a rectangle, and the sound pressure distribution An object of the present invention is to provide a speaker horn capable of reducing a change due to frequency.

[0007]

In order to achieve the above object, in the speaker horn of the present invention, a cross section parallel to the throat is defined by eight points of horizontal, vertical and diagonal cross sections. The angle α between the horizontal cross section and the oblique cross section and the target directivity angle in the oblique direction are defined from the target directivity angle and the vertical target directivity angle of, and the horizontal cross section, the vertical cross section, and the oblique cross section are It is a combination of curves having two different average opening angles with respect to the target directivity angle 2θ in each direction, and the average opening angle on the throat side is 0.8 to 1.2θ with respect to the target directivity angle 2θ in that direction. And 1. on the opening side.
1θ to 2θ, and when the length from the throat to the opening is different, a curve having a short length is translated to the opening side so that the opening portions match.

Therefore, according to the present invention, by constructing the speaker horn as described above, it is possible to prevent the sound pressure from decreasing in an oblique direction and obtain a sound pressure distribution close to a rectangle, and the sound pressure distribution. It is possible to reduce the change due to the frequency of.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention.
Is a closed splice whose cross section parallel to the throat passes through 8 points.
The shape of the horn is two, and two of the eight points are vertical sections of the horn.
And the other two points are on the horizontal section of the horn.
The remaining 4 points are the horizontal cross section with respect to the horn center axis.
A horn rotated by an angle α counterclockwise and clockwise
Is a point on the cross section in the diagonal direction, and the horizontal target directivity angle is 2θ.
_hAnd the vertical target directivity angle is 2θ. _vWhere α = tan^-1(Q × tan θ_v) / (P × tan θ_h) (6) α: Angle between oblique section and horizontal section θ_v: Half the vertical target pointing angle θ_h: Half of the horizontal target directivity angle p: Coefficient 1 ≦ p ≦ 1.3 q: Coefficient 1 ≦ q ≦ 1.3
The angle is θ_d= Tan^-1 (R × √ ((p × tan θ_h)^Two+ (Q x tan θ_v)^Two)) (7) θ_d: Half of the diagonal target directivity angle r: Coefficient 1 ≤ r ≤ 1.5, and the horizontal, vertical and diagonal cross sections are
It is a combination of curves with two different average opening angles.
On the throat side, the average opening angle is the target directivity angle in that direction.
0.8 to 1.2θ with respect to 2θ, and 1.
1 to 2θ, which is slanted in the horizontal, vertical, and diagonal directions.
If the length from the port to the opening is different,
Move the short curve parallel to the opening side to
A straight line with an average opening angle of ± 20 ° or less on the funnel side or
It is characterized by having a shape that combines curves.
The horizontal and vertical cross sections are represented by the combination of the above curves.
Therefore, the horizontal and vertical directional angles have a wide frequency range.
It takes a value close to the target directivity angle for several horizon, and it
Angle α between target cross sections and target directivity angle
Calculated from the directivity angle and the vertical target directivity angle, and the cross-sectional shape is
Since the shape is a combination of curved lines, the sound in an oblique direction
It is possible to prevent pressure drop and obtain a sound pressure distribution close to a rectangular shape.
Also, the change in sound pressure distribution due to frequency can be reduced.
effective.

The invention according to claim 2 of the present invention is a horizontal method.
There are two different cross-sections in the vertical, vertical, and diagonal directions.
Is a combination of curves with a
Diameter y ₁Is the opening radius a_m0.3 to 0.8 times that of
The curve on the wireless side is y = √ (a_t ^Two+ Tan^Twoθ · x^Two) (8) x: distance from throat y: radius of cross section at distance x from throat a_t: Radius of throat θ: Expressed by half of the target directivity angle in the relevant direction, and on the aperture side, y = k (xx₁) + (A_m-Y₁-K (a_m-Y₁) / Tan θ_Two) × ((xx₁) ・ Tan θ_Two/ (A_m-Y₁))ⁿ+ Y₁(9) a_m: Cross-sectional radius at opening x₁: Distance from the throat to the junction of the two curves y₁: Radius of joint between two curves (0.3a_m≤ y₁≤
0.8a_m) K: differential coefficient θ of the joint in equation (8)_Two: Average opening angle of the curve on the opening side (θ ≤ θ_Two≦ 2θ) n: Represented by a coefficient (2 <n <5), according to the above formula in the horizontal direction, the vertical direction, and the diagonal direction.
If the length from the throat to the opening calculated by
In the case of_t
To 0.6-2.5 times the throat radius, and
Move parallel to the opening side so that the opening parts match and throw
Straight line or curve with an average opening angle of ± 20 ° or less
2. The shape according to claim 1, wherein
If it is a speaker horn and only satisfies claim 1.
For comparison, the horizontal, vertical, and diagonal sections should be represented by mathematical expressions.
By designing the cross-sectional design of each direction of the horn,
For a wide horizontal and vertical directional angle.
Decrease the deviation from the target directivity angle in the wave number range, and
It is possible to prevent pressure drop and obtain a sound pressure distribution close to a rectangular shape.
Also, the change in sound pressure distribution due to frequency can be reduced.
effective.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. In this embodiment, the case where θ _h > θ _v is described. FIG. 1 is a perspective contour map of a horn according to an embodiment of the present invention, and FIG. 2 is a front contour map thereof. In FIG. 1, 1
Is a horizontal section, 2 is a vertical section, 3 and 4 are diagonal sections.
The horizontal directivity angle is 2θ _h , the vertical directivity angle is 2θ _v , and the angle between the oblique cross sections 3 and 4 and the horizontal cross section 1 is represented by α in the equation (6).

In FIG. 2, reference numeral 5 is an example of a cross section parallel to the throat, and two points 8 and 12 on the vertical cross section 2 and two points 6 and 10 on the horizontal cross section 1 and oblique cross sections 3 and 4 are shown. It has a closed spline shape that passes through a total of 8 points of 4 points 7, 9, 11, and 13. The target directivity angle in the direction of the oblique cross sections 3 and 4 is twice θ _d in the equation (7), and it is obvious from this equation that θ _d > θ _h > θ _v .

FIG. 3 (a) is a sectional diagram of a horn according to the present invention at a horizontal section 1, FIG. 3 (b) is a sectional diagram at oblique sections 3 and 4, and FIG. FIG. 3 is a sectional line diagram in a vertical section 2. 3 (a), (b) and (c), 14, 14 'and 16, 16' and 18, 1
On the opening side from 8 ', each cross section is expressed by the equation (9), and on the throat side, it is expressed by the equation (8). Since a _{θ d> θ h> θ v} , horn length is long 1 ₃ vertical section the most, one value of a _t the value of a _t in equation (8) is a horizontal section in the equation of the vertical section A value of 5 times is taken, and a straight line with an average opening angle of 2 ° is connected to the throat side by the difference 1 _{1 in} horn length from the vertical section. The value of even a _t an oblique section is intended to take 1.5 times the value of a _t in the formula of the vertical section, the straight line of the average opening angle 5 ° by the difference 1 ₂ horn length throat side Are connected.

FIG. 4 shows vertical directional angular frequency characteristics of the horn in this embodiment. It can be seen that the value is close to the target directivity angle in a wide frequency range.

FIG. 5 shows a sound pressure distribution on a surface parallel to the horn opening surface in the present embodiment. Compared with the sound pressure distribution of the conventional horn shown in FIG. 10, a sound pressure drop in an oblique direction is prevented, a sound pressure distribution close to a rectangular shape is obtained, and the change of the sound pressure distribution with frequency is small. I understand.

[0016]

As described above, according to the present invention, as is apparent from the above-described embodiment, the horizontal directivity angle and the vertical directivity angle take a value close to the target directivity angle in a wide frequency range, and the sound in the oblique direction is obtained. There is an effect that a pressure drop can be prevented, a sound pressure distribution close to a rectangular shape can be obtained, and a change in the sound pressure distribution due to frequency can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective contour diagram of a speaker horn according to an embodiment of the present invention.

FIG. 2 is a front contour map of the speaker horn shown in FIG.

3A is a horizontal sectional view of the horn shown in FIG. 1, FIG. 3B is a sectional view of a diagonal direction intersecting the horizontal sectional view of the horn shown in FIG. 1 at an angle α, and FIG. Vertical cross-section diagram of the horn shown in 1.

FIG. 4 is a vertical directivity diagram of a horn according to an embodiment of the present invention.

FIG. 5 is a sound pressure distribution diagram of the horn according to the embodiment of the present invention.

FIG. 6 is a schematic diagram for explaining a method of measuring sound pressure distribution.

FIG. 7 is a perspective view of a conventional speaker horn.

FIG. 8 is a front view of a speaker horn in a conventional example.

9A is a horizontal sectional view of the conventional horn shown in FIG. 7, FIG. 9B is an oblique sectional view of the conventional horn shown in FIG. 7, and FIG. 9C is a conventional sectional view of FIG. Vertical section diagram of the horn

FIG. 10 is a sound pressure distribution diagram of the conventional horn shown in FIG.

[Explanation of symbols]

1 horizontal cross section 2 vertical cross section 3, 4 diagonal cross section 5 cross section parallel to throat 6, 7, 8, 9, 10, 11, 12, 13 8 points through which cross section 5 passes 14, 15 horizontal function coupling points 16, 17 Coupling point of diagonal function 18 Coupling point of vertical function 19 Surface for measuring sound pressure distribution 20 Horizontal section 21 Vertical section 22, 23, 24, 25 Horn side wall 26 Oblique section 27 Coupling point of horizontal function 28, 29 Variation of oblique function Inflection point 30 Connection point of vertical function

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoshi Hirai, Isamu Matsushita Communication Industrial Co., Ltd., 4-3 Tsunashima-higashi, 3-chome, Kohoku-ku, Yokohama-shi, Kanagawa

Claims (2)

[Claims] 1. A cross-section parallel to the throat has a closed spline shape that passes through eight points, two of the eight points are points on a vertical section of the horn, and another two points are horizontal sections of the horn. The remaining four points are points on the diagonal cross section of the horn obtained by rotating the horizontal cross section clockwise and counterclockwise with respect to the horn center axis by an angle α, and the horizontal target directivity angle is 2θ. _h , the vertical target directivity angle is 2θ _v , and α = tan ⁻¹ (q × tan θ _v ) / (p × tan θ _h ) ... (1) α: angle between the diagonal section and the horizontal section θ _v : Half of the vertical target directivity angle θ _h : Half of the horizontal target directivity angle p: Coefficient 1 ≦ p ≦ 1.3 q: Coefficient 1 ≦ q ≦ 1.3 Represented by the relational expression and in the diagonal direction The target directivity angle at is θ _d = tan ⁻¹ (r × √ ((p × tan θ _h ) ² + (q × tan θ _v ) ² )) (2) θ _d : Half of the diagonal target directivity angle r: Coefficient 1 ≦ r ≦ 1.5, and the curves in the horizontal, vertical, and diagonal cross sections each have two different average opening angles The average opening angle is 0.8 to 1.2θ with respect to the target directivity angle 2θ of the direction on the throat side, and the average opening angle on the throat side is 1.
1 to 2θ, and if the length from the throat to the opening is different in the horizontal, vertical, and diagonal directions, move the curve with a short length parallel to the opening side so that the opening parts match, and move to the throat side. A speaker horn having a shape in which straight lines or curved lines having an average opening angle of ± 20 ° or less are combined. 2. The horizontal, vertical, and diagonal cross-sections are a combination of curves each having two different spreading rates, and the radius y ₁ at the connection is 0.3 of the opening radius a _m .
Is 0.8 times, the curve of the throat ^{_{side, y = √ (a t 2}} + tan 2 θ · x 2) ··· (3) x: distance from the throat y: radius of the cross section of the distance x from the throat a _t: the radius of the throat theta: is represented by one half of the target directivity angle of the direction, the opening side, y = k (x-x 1) + (a m -y 1 -k (a m -y 1) / _{tanθ 2) × ((x-} x 1) · tanθ 2 / (a m -y 1)) n + y 1 ··· (4) a m: cross section at the opening radius x _1: binding of the two curves from the throat distance to part y _1: binding of the two curves radius (0.3a _m ≦ y ₁ ≦
0.8a _m ) k: differential coefficient of the joint portion in Expression (3) θ ₂ : average opening angle of the curve on the opening side (θ ≦ θ ₂ ≦ 2θ) n: expressed by a coefficient (2 <n <5), When the length from the throat to the aperture calculated by the above formulas in the horizontal direction, the vertical direction, and the diagonal direction is different, the curve of the cross section with the short horn length is a _t in the formula (3).
Is set to a value of 0.6 to 2.5 times the radius of the throat, and is translated to the opening side so that the opening portions match, and a straight line or a curve with an average opening angle of ± 20 ° or less is connected to the throat side. The speaker horn according to claim 1, wherein the horn has a curved shape.