JP4290911B2 - Horn speaker - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a horn speaker, and more particularly to a horn speaker whose directivity is controlled.
[0002]
[Prior art]
The directivity characteristics of a horn speaker are determined by the opening diameter of the horn and the throat angle or horn length of the horn. The opening diameter, throat angle, and horn length of the horn are in the relationship between the side of the triangle and the inner angle. If two of the opening diameter, throat angle, and horn length of the horn are determined, the remaining one is naturally Determined. The directivity angle of the horn speaker is determined by the throat angle, and the limit frequency of directivity control in the low sound range is determined by the horn opening diameter.
[0003]
[Problems to be solved by the invention]
In a horn speaker, if the length of the horn is shortened while maintaining the horn opening diameter at a predetermined value, the throat angle is increased and the directivity is increased. On the other hand, if the throat angle is maintained in order to maintain the predetermined directivity, the opening diameter of the horn becomes small and directivity in the low sound range cannot be obtained.
[0004]
An object of the present invention is to provide a horn speaker capable of shortening the length of a horn without increasing the horn opening diameter and reducing the directivity angle. Another object of the present invention is to provide a horn speaker having a narrow directivity without changing the horn opening diameter and the horn length.
[0005]
[Means for Solving the Problems]
The horn speaker according to the present invention has a horn having an opening on the front surface. Various types of horns can be used. For example, a parabolic horn, an exponential horn, a high parabolic horn, or the like can be used. A cone speaker is provided in the horn . A directivity controller is provided in a position in front of the cone speaker in the horn. The horn is composed of two horn inner surfaces arranged opposite to each other at an interval, and the distance between the horn inner surfaces decreases smoothly from the front to the rear. The directivity controller has a rear end portion on the cone speaker side, and has a front end portion disposed on the horn opening side so as not to protrude from the front surface of the horn, and the rear end portion and the front end portion Are connected by the peripheral surface. The center of the surface of the rear end portion facing the cone speaker is a concave portion approximate to the dust cap of the cone speaker, and the shape approximates to the front surface from the center of the cone to the middle. The diameter increases toward the outside from the peripheral surface of the concave portion, and the rear end portion has a curved portion formed concave toward the inside of the directivity controller. The peripheral surface portion has a curved portion that gradually increases in diameter from the front edge of the curved portion at the rear end portion toward the front surface of the horn and is convex toward the outside of the directivity controller. The front edge of the curved portion of the peripheral surface portion is the maximum diameter portion of the directivity controller, and is set approximately equal to the effective vibration diameter of the cone speaker when the horn side is viewed from the front opening of the horn. ing.
[0006]
In a normal horn speaker not provided with a directivity controller, a substantially spherical sound surface centering on the throat of the horn is formed, and sound is output at a directivity angle along this. In this case, the center of the sound wave surface swells most outward. On the other hand, when the directivity controller is provided in the horn as in the present invention, two sub horns are formed in the horn. The sound wave surface radiated from each sub horn has the most swelled position corresponding to the center of these sub horns, and the most concave shape at the front end of the directivity controller. Therefore, the synthesized sound wave surface radiated from the opening surface of each sub-horn is suppressed from bulging at the position corresponding to the front end of the directivity controller, and compared to a horn speaker without a directivity controller. Thus, the sound wave surface has a shape closer to a plane wave, and can have narrow directivity. Therefore, the length of the horn can be shortened without widening the horn opening diameter and the directivity angle, and when the horn opening diameter and the horn length are constant, it is narrower than when no directivity controller is provided. A horn speaker with directivity can be obtained.
[0008]
In addition, a plurality of virtual point sound sources are formed at the outermost part of a narrow space between the curved portion of the peripheral surface portion of the directivity controller and the cone speaker . Of these virtual point sound sources, consider two virtual point sound sources at target positions with a pointing controller in between. Part of the sound radiated from the virtual point sound source on one side of the directivity controller travels along the circumferential surface of the directivity controller toward the front end of the directivity controller, and rotates at the front end. To a point on the other side of the directivity controller. Part of the sound radiated from the other virtual point sound source on the other side of the cone speaker goes directly to the certain point on the other side without following the peripheral surface of the directivity controller. Both sounds are synthesized at the certain point on the other side, but the sound radiated from the virtual point sound source on one side is equivalent to the amount that has traveled along the peripheral surface of the directivity controller. The sound is delayed from the sound from the virtual sound source, and when both sounds are synthesized at the certain point on the other side, a dip is likely to occur. That is, directivity control is performed.
[0009]
A surface of the directivity controller that faces the cone speaker at the rear end portion is a concave portion approximate to a dust cap of the cone speaker, and is approximate to a front surface from the center of the cone speaker to the middle. Since the diameter increases toward the outside from the peripheral surface of the concave portion so as to form a shape, and a curved portion formed concave is formed toward the inside of the directivity controller, the rear of the directivity controller The distance between the end portion and the vibration surface of the sound source can be made closer, and the directivity can be controlled well as described above. Furthermore, it is possible to prevent deterioration of the high sound range. That is, generally, the area of the cross section perpendicular to the sound traveling direction in the sound passage way increases gradually, so that deterioration of sound quality can be prevented. When a bag-like space is created in the middle of a sound passage, an equalizer that cuts the high frequency range is formed, and the high frequency range deteriorates. By approximating the shape of the rear end portion of the directivity controller to the vibration surface of the cone speaker, such a space for cutting the high sound region is not formed, and deterioration of the high sound region can be prevented.
[0010]
The peripheral surface between the front end edge of the curved portion of the peripheral surface portion of the directivity controller and the front end portion may be formed as a body portion having a non-concave shape toward the outside having the maximum diameter. . In this case, when the diameter increases from the rear end portion toward the front end portion and then decreases, or after the diameter increases from the rear end portion toward the front end portion, the diameter increases toward the front end portion. If the diameter is reduced by a certain distance and then the diameter decreases toward the front end, or if the diameter of the front edge of the rear end is maintained, the diameter is extended by a certain distance toward the front end, and then the front end. Sometimes it is connected. When formed in this way, there is no constricted portion in the entire peripheral surface, and the directivity is not disturbed.
[0011]
The directivity controller can be arranged in the center of the horn. In this case, the peripheral surface between the rear end portion and the front end portion of the directivity controller is formed so as to form two sub-horns having substantially the same shape in the horn together with the two horn inner surfaces of the horn. Is formed. For example, when the longitudinal cross-sectional shape passing through the center from the rear end portion to the front end portion of the directivity controller is divided into two by a line segment passing through the center, the outer peripheral edge of the divided portion is a horn facing it. It is formed in a shape that is substantially line-symmetric with the peripheral edge without any gap.
[0012]
When configured in this way, two sub-horns are formed in the same manner as described above, and the directivity can be narrowed. However, since the directivity controller is arranged in the center of the horn, The shape is almost the same, and the swelling of the sound wave surface near the center of the horn can be surely suppressed, and a sound wave surface closer to a plane wave can be obtained, and control with narrow directivity is performed well.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
The horn speaker of one embodiment of the present invention has a horn 2 as shown in FIGS. 1 (a) and 1 (b). The horn 2 is composed of two horn inner surfaces 4a and 4b formed opposite to each other. These horn inner surfaces 4a and 4b are inner surfaces of two hollow bimodal portions 6a and 6b that are spaced apart from each other. The two bimodal portions 6 a, 6 b are arranged at an interval in the longitudinal direction of the long base 8. Since the horn 2 has such a configuration, the vertical direction in FIG. 1B is opened.
[0015]
The horn inner surfaces 4a and 4b are formed in line symmetry with respect to the center in the length direction and the width direction of the base 8, that is, the central axis standing perpendicular to the center of the horn. The distance between the horn inner surfaces 4a and 4b is It decreases smoothly from the front side toward the rear. As shown in FIG. 1A, the horn 2 has, for example, an opening diameter D and a length L of about 260 mm and about 150 mm, respectively. In the horn 2, the ratio of the opening diameter D to the length L is approximately 1.7, and the length L is shorter than the opening diameter D. The throat angle θ is about 30 degrees. As the shape of the horn inner surfaces 4a and 4b, various known shapes such as a parabolic type, a conical type, an exponential type or a high parabolic type can be used. The horn 2 is made of, for example, a synthetic resin.
[0016]
A sound source section, for example, a cone speaker 10 is arranged behind the rear end portions of the horn inner surfaces 4a and 4b. The cone speaker 10 is also mounted so that its central axis is located on the central axis (the center of the horn 2) standing on the base 8 and its radiation surface faces the opening side of the horn 2. Yes. The cone speaker 10 has a cone 10a, and the maximum diameter of the cone 10a is about 110 mm. A dust cap 10b is provided at the center of the cone 10a. Further, the cone speaker 10 has a base 10d having a magnet 10c and a pole piece (not shown).
[0017]
A directivity controller 12 is disposed inside the horn 2 and in front of the cone speaker 10. This directivity controller 12 is formed in a hollow body having a substantially egg shape. The directivity controller 12 is fixed to the horn inner surfaces 4 a and 4 b by two fins 14 and 14 provided in the middle of the peripheral surface of the directivity controller 12. This directivity controller 12 is also made of synthetic resin.
[0018]
The directivity controller 12 has a rear end portion 13 located on the horn speaker 10 side and a front end portion 15 located on the opening side of the horn 2. A central axis that connects the center of the rear end 13 and the center of the front end 15 is located on the central axis of the base 8. In this directivity controller 12, the vertical cross-sectional shape along the central axis is configured as shown in FIG. 1A, and the vertical cross-sectional shape is a line-symmetric shape with the central axis of the base 8 as the symmetry axis. Is formed.
[0019]
In the directivity controller 12, the center of the rear end portion 13 is a recess 16 that has an approximate shape with the dust cap 10b. A curved portion 18 whose diameter gradually increases from the periphery of the recess 16 toward the outside is formed so as to have a shape approximate to the shape of the front surface from the center of the cone 10a toward the middle. . The curved portion 18 is formed concave toward the inside of the directivity controller 12.
[0020]
A peripheral surface portion 19 is formed from the front peripheral edge of the curved portion 18 toward the front surface. The peripheral surface portion 19 is formed in a non-concave shape, for example, a convex shape from the inside of the directivity controller 12 toward the outside as a whole. In the peripheral surface portion 19, the bending portion 20 extends from the front end edge of the bending portion 18 toward the front end portion 15 side. The curved portion 20 gradually increases in diameter, but is formed so as to protrude outward from the directivity controller 12. The body portion 22 of the peripheral surface portion 19 extends to the vicinity of the fin 14 while maintaining substantially the same diameter from the front end edge of the curved portion 20. The fin 14 and the directivity controller 12 are integrally formed. A curved portion 24 is formed toward the front end portion 15 of the directivity controller 12 while gradually reducing the diameter from the front end edge of the body portion 22. The curved portion 24 is formed so as to protrude outward from the inside of the directivity controller 12.
[0021]
The front end portion 15 of the directivity controller 12 is not pointed and rounded, and the maximum diameter is smaller than the maximum diameter of the rear end portion 13.
[0022]
Since it is configured in this manner, the entire peripheral surface portion 19 including the bending portion 20, the body portion 22, and the bending portion 24 has no constricted portion and is formed smoothly.
[0023]
The front end portion 15 of the directivity controller 12 does not protrude from the front opening of the horn 2, and is located, for example, about 35 mm deep from the front opening. That is, it is located on the far side from the opening surface of the horn 2 by a length of about 0.2 times the length L of the horn 2. The length L1 of the directivity controller 12 in the front-rear direction is about 128 mm, which is shorter than the length L of the horn 2. Further, the maximum diameter portion D1 viewed from the front side of the horn 2, that is, the diameter of the trunk portion 22, is formed to be about 88 mm, which is smaller than the opening diameter D of the horn 2, and the cone 10a of the cone speaker 10 is connected to the horn 2. Is substantially equal to the effective vibration diameter of the cone 10a (a distance from the center of the bellows portion at the outermost periphery of the cone speaker), for example, about 90 percent of the effective vibration diameter. The diameter of the body portion 22 can be 90% or more of the effective vibration diameter.
[0024]
Further, the length L1 in the front-rear direction of the directivity controller 12 is formed larger than the maximum diameter D1 of the directivity controller 12. Further, the rear end portion 13 of the directivity controller 12 and the cone speaker 10 are disposed relatively close to each other, for example, close to each other within a range where the vibration surface and the rear end portion 13 of the directivity controller 12 do not contact each other. Specifically, they are 10% or less of the effective vibration diameter, and are arranged close to each other as long as they do not contact the vibration surface and the directivity controller 12. For example, the distance L3 from the outer edge of the recess 16 to the tip of the dust cap is set to about 10 mm.
[0025]
In the horn speaker configured as described above, since the directivity controller 12 is provided, it is equivalent to a plurality of, for example, two sub-horns formed in the horn 2 at some intervals. Moreover, these sub-horns have the same shape and the same directivity angle as the horn 2 in this embodiment.
[0026]
By the way, when the directivity controller 12 is not provided, the sound wave surface of the sound radiated from the horn 2 becomes a spherical surface as indicated by the symbol a in FIG. The sound spreads. This spherical surface has a wide directivity because the upper part of the horn axis swells most.
[0027]
On the other hand, in the case where the directivity controller 12 is provided, the sound wave surface radiated from each sub horn swells most at the portion corresponding to the central portion of each sub horn, as shown by the symbol b in FIG. The spherical wave is the most depressed at the front end 15 of the sex controller 12. These spherical waves are combined, and the sound wave surface is controlled by providing the directivity controller 12 in a shape as shown by reference numerals b 1 and b 2, that is, in a shape in which the bulge of the central portion of the horn 2 is suppressed. . Therefore, for example, as indicated by reference signs a1 and b2, when the sound wave surface with the directivity controller 12 provided at the same position in front of the horn 2 is compared with the sound wave surface with no directivity, the directivity is obtained. When the property controller 12 is provided, the sound wave surface has a shape closer to a plane wave than when the property controller 12 is not provided. Therefore, the sound spreads in a direction perpendicular to the wavefront, but the spread is suppressed, and this is equivalent to the formation of a sound wave surface by a horn having a sharp directivity angle, that is, a long horn length. Such control of the sound wave surface is effective mainly in the midrange.
[0028]
Further, when the same sound having a certain frequency in the high frequency range is emitted from the points d and e in the space formed by the rear end portion of the directivity controller 12 and the cone speaker 10, the sound from the point d is, for example, Go straight as indicated by the solid line, for example, to reach point f. On the other hand, the sound from the point e reaches the front end portion 15 along the length direction of the directivity controller 12, for example, as shown by a solid line, wraps around the point f side, and reaches the point f. At this time, the propagation distance of the sound from the point e is longer than the propagation distance of the sound from the point d, and a phase difference occurs between the two sounds. When this phase difference is exactly 180 degrees, a dip occurs. Even if it does in this way, this horn speaker is especially effective in a high sound range rather than the case where the directivity controller 12 is not provided.
[0029]
Therefore, this horn speaker 2 has directivity as shown by a one-dot chain line that is narrower than when the directivity controller 12 is not provided at a certain frequency. Similarly, other frequencies have a narrow directivity.
[0030]
In order to obtain good directivity, the front end portion 15 does not protrude from the opening surface of the horn 2, the front end portion 15 is rounded, the peripheral surface portion 19 of the directivity controller 12 is not constricted, and directivity The maximum diameter D of the controller 12 is approximately equal to or larger than the effective vibration diameter of the cone speaker 10, the peripheral surface 19 of the directivity controller 12 is formed to be convex outward, and the directivity It is desirable that the length L of the sex controller 12 is larger than the maximum diameter D.
[0031]
In this horn speaker, since the directivity controller 12 is disposed close to the cone speaker 10, the sound emitted from the cone speaker 10 surely goes around the front end 15 of the directivity controller 12, Control with good directivity can be performed. If there is a large interval between the directivity controller 12 and the cone speaker 10, the sound that wraps around the rear end portion 13 of the directional controller 12 increases, and the sound that wraps around the front end portion 15 side decreases. , Good directivity control can not be performed. Further, the surface of the directivity controller 12 facing the sound source, in this embodiment, the shape of the concave portion 16 and the curved portion 18 is approximated to the shape of the cone 10a. It is possible to prevent deterioration of the sound range.
[0032]
In this way, in this horn speaker, the directivity controller 12 is controlled to have a narrow directivity, so that the length of the horn can be increased without increasing the horn opening diameter or reducing the directivity angle. Can be shortened. Further, this horn speaker can have a narrow directivity without changing the horn opening diameter, the horn length, and the directivity angle. Moreover, since the directivity controller 12 is housed inside the horn 2, the horn speaker as a whole is larger than when a dufuser is attached or when an acoustic lens is provided to narrow the directivity. There is no. In some cases, an equalizer is provided in the horn speaker. This is provided in the throat of the horn speaker, and the sound wave, which is a spherical wave from the driver, is a plane wave. Therefore, the equalizer does not affect the directivity of the horn speaker.
[0033]
In the above embodiment, a cone speaker is used as a sound source. However, a driver unit similar to a dome type usually used for a horn speaker can be used as a sound source. In the above-described embodiment, the peripheral surface portion 19 of the directivity controller 12 is provided with the body portion 22 having a constant diameter. However, the shape is such that this is removed and the bending portion 20 is immediately coupled to the bending portion 24. You can also In this case, it is desirable that the joining surfaces of the curved portions 20 and 24 be smooth. Further, although the front end portion 15 of the directivity controller 12 is provided on the back side of the opening surface of the horn 2, the front end portion 15 may be positioned on the opening surface of the horn 2. In the above embodiment, since the up and down direction of the horn 2 in FIG. 1B is opened, only two sub horns are configured by arranging the directivity controller. When viewed from the front opening side, the number of auxiliary horns can be three or more.
[0034]
【The invention's effect】
As described above, according to the present invention, by providing the directivity controller, the horn speaker can have a narrow directivity, so that the horn opening diameter is not increased and the directivity angle is not reduced. The length of the horn can be shortened, and the entire horn speaker does not become large.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view and a plan view of a horn speaker according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram of directivity of the horn speaker of FIG.
[Explanation of symbols]
2 Horn 4a 4b Horn inner surface 10 Cone speaker (sound source)
12 Directional controller

Claims (3)

A horn having an opening on the front surface;
A cone speaker provided in the horn;
An approximately egg-shaped directivity controller provided at a position in front of the cone speaker in the horn;
Equipped,
The horn is composed of two horn inner surfaces arranged to face each other at a distance, and the distance between the horn inner surfaces decreases smoothly from the front to the rear.
The directivity controller has a rear end portion on the cone speaker side, and has a front end portion disposed on the horn opening side so as not to protrude from the front surface of the horn, and the rear end portion and the front end portion Are connected by the peripheral surface,
The center of the surface facing the cone speaker at the rear end is a concave portion approximate to the dust cap of the cone speaker, and the shape approximates to the front surface from the center of the cone to the middle. The diameter increases as it goes outward from the peripheral surface of the recess, and the rear end portion has a curved portion formed concave toward the inside of the directivity controller,
The peripheral surface portion has a curved portion that gradually increases in diameter as it goes from the front edge of the curved portion at the rear end portion toward the front surface of the horn and is convex toward the outside of the directivity controller, The front edge of the curved portion of the peripheral surface portion is the maximum diameter portion of the peripheral surface portion, and is set approximately equal to the effective vibration diameter of the cone speaker when the horn side is viewed from the front opening of the horn. /> Horn speaker. In the horn speaker according to claim 1, wherein the non-concave outward Chi lifting the maximum diameter peripheral surface between the peripheral surface portion the curved portion front end edge and the front end of the directional controller A horn speaker formed on the shape of the body.   2. The horn speaker according to claim 1, wherein the directivity controller is disposed at a center of the horn, and a peripheral surface between the rear end portion and the front end portion of the directivity controller is 2 of the horn. A horn speaker formed into a shape in which two sub-horns having substantially the same shape are formed in the horn together with the inner surfaces of the two horns.

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