JPS6216060Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a horn speaker having a phase-equivalent function.

FIG. 1 shows a conventional horn speaker with a phase equalizer inside the horn. In this figure, 1 is a phase equalizer, 2 is a horn, 3 is a throat, 4 is a sound path inside the horn, 5 is a frequency, 5g is an air gap in front of the diaphragm 5, 6 is a voice coil, 7 is a center hole, Reference numeral 8 represents a magnet, and reference numeral 9 represents a driving section constituting a magnetic circuit.

In general, a horn speaker having a phase equalizer inside the horn has conventionally been constructed as shown in FIG. 1 in order to widen the reproduced frequency band. 1st
In the design of the throat 3 position composed of such an annular slit as shown in the figure, due to the phase relationship depending on the wavelength of the sound wave inside the air gap 5g,
The throat 3 position is generally designed from the center of the radius of the air gap 5g to a location close to the outer periphery. However, in a device equipped with such a phase equalizer, the sound pressure distribution in the radial direction within the air gap 5g changes with the frequency, and as the frequency increases, the sound pressure near the throat 3 becomes extremely small and the horn The sound pressure radiated from the speaker is reduced,
As shown by the broken line a in FIG. 2, the sound pressure characteristics deteriorate at frequencies near the upper limit of the reproduction frequency where the wavelength becomes shorter.

One way to improve the above problem is to increase the number of slits in the throat section and create a double or triple slit structure, but this does not essentially improve the problem caused by the sound pressure distribution in the air gap. . Furthermore, a phase equalizer having double or triple annular slits has a complicated structure, making it difficult and expensive to manufacture.

Furthermore, there is a horn speaker equipped with a phase equalizer having a plurality of concentric annular slit structures as shown in FIG. This is the same as the case shown in FIG. 1, and there was a problem in that the characteristics deteriorated at higher frequencies in the reproduction frequency band. In order to improve this problem, there has been an attempt to make the throat section of the phase equalizer into a plurality of radial slits in the structure of the drive section 9 as shown in FIG. By using such a phase equalizer having a plurality of radial slit structures, it is possible to eliminate the deterioration of characteristics due to the sound pressure distribution occurring in the radial direction within the air gap as described above. However, in the horn speaker of the type shown in FIG. 3, the drive section 9 has a more complicated structure than the horn speaker shown in FIG. Dimensional accuracy is required to manufacture and install the drive unit 9 inside the drive unit 9, and the drive unit 9 and the phase equalizer are expensive. Furthermore, when attaching the horn 2 to the drive unit 9, dimensional accuracy is required, and at the same time, the number of parts is larger and more expensive than the horn speaker of the type shown in FIG. Ta.

Further, there is a horn speaker having a structure in which a phase equalizer having a radial opening is provided inside the horn, and the phase equalizer extends to the horn opening. However, in this type of horn speaker, although the deterioration of frequency characteristics in the high range of the reproduced frequency band as described above is significantly improved, the horn internal space near the horn opening is divided in the radial direction by the partition wall. Therefore, there was a problem in that the wavefront of the sound wave at the horn opening became more like a plane wave than in the case without the partition wall, and the directivity characteristics deteriorated.

The present invention was made to eliminate the above-mentioned drawbacks, and is designed to provide a horn speaker equipped with a phase equalizer located in front of the diaphragm and inside the horn. The area of the surface perpendicular to the sound axis increases exponentially toward the exit side of the horn, and the length between adjacent openings is the wavelength of the upper limit frequency of the reproduction frequency range at the outermost periphery. A phase equalizer in which a plurality of independent radial slits are formed over the entire length and a plurality of partition walls arranged radially is provided. The maximum width (wall thickness) of the phase equalizer is made shorter on the horn opening side of the phase equalizer than on the diaphragm side, and a sharp edge is provided on each bulkhead at the end of the phase equalizer on the horn opening side. By creating a structure in which the length of the phase equalizer is made shorter than the length of the phase equalizer, the sound pressure frequency characteristics in the high frequency range can be significantly improved without impairing the sound pressure frequency characteristics in the low frequency range of the horn speaker. The purpose is to provide an economical phase equalizer that has a simple structure and is easy to integrally mold.

The details of this invention will be explained below according to the illustrated embodiments.

Figures 4 to 7 are diagrams showing an embodiment of this invention, and Figures 5 to 7 are examples of only a phase equalizer, and the length of the phase equalizer 1 in the sound axis direction is 2
It is shorter than the length of.

In each figure, 101, 102, 10
Reference numerals 3, 104, 106, and 107 are seven partition walls, each of which is integrally formed by molding or machining from a single metal material (for example, aluminum). Further, in the case of a mold, it is also possible to form each of the partition walls 101 to 107 and the horn 2 integrally with a mold, which is easier and cheaper to manufacture. The width (thickness) of the outermost peripheral portions of these partition walls 101 to 107 gradually decreases (thinner) from the diaphragm 5 side toward the opening side of the horn 2. 111,112,1
13, 114, 115, 116, 117 are openings formed between the partition walls, 111a, 112
a, 113a, 114a, 115a, 116a,
Reference numeral 117a denotes the entrance part of the sound wave generated by the diaphragm 5, and the length between adjacent openings is the wavelength of the upper limit frequency of the reproduction frequency (hereinafter λ) at the outermost periphery.
) has been reduced to less than 1/2. Furthermore, horn 2
The inner diameter of the sound wave inlet side is larger than the diameter of the dome portion of the diaphragm 5. γ is the radius of the inner diameter of the throat opening of the interconnection part of each bulkhead, and the radius in the direction perpendicular to the sound axis is 1/4
It is formed below λ. The openings 111a to 117a of the throat portion are provided radially, and the independent openings 111 to 117 extend over the entire length of the phase equalizer 1 along the central axis in the sound axis direction. Furthermore, each of the openings 111 to 117 is configured such that the area of the surface perpendicular to the sound axis gradually increases exponentially from the sound wave inlet side 111a to 117a of the phase equalizer 1 toward the sound wave outlet side. In addition, by making the shape of the aperture of the phase equalizer 1 wider at the outer periphery than at the center in a plane perpendicular to the sound axis,
This allows for integral molding using a mold. This is the same in the case of only the phase equalizer and in the case of integral molding of the phase equalizer and the horn. Furthermore, the shape of the opening formed by each partition of the phase equalizer is approximately fan-shaped in a plane perpendicular to the sound axis, and the opening angle of the fan-shaped opening is made larger on the horn opening side than on the horn throat. This makes integral molding easier.

The sound pressure characteristics in the embodiments shown in FIGS. 4 to 7 above are as shown by the solid line b in FIG. 2, and as can be seen from the comparison with the broken line a in FIG. As is clear from the comparison with the conventional sound pressure characteristic a, there is almost no deterioration in the sound pressure in the high frequency range. As mentioned above, this is achieved by making the throat of the phase equalizer have multiple radial slits (openings) and making the outer diameter of the radial slits almost the same as the outer diameter of the diaphragm. It was a gift. Furthermore, these apertures are arranged independently along the central axis of the phase equalizer in the sound axis direction over the entire length of the phase equalizer,
The phase equalizer has a structure in which the area of the plane perpendicular to the sound axis increases exponentially toward the exit side of the horn, so that the structure is simple and the phase equalizer is Since it can be integrally molded with the horn, it is easy to manufacture and cost-effective.

Further, if the number of openings 111 to 117 is plural, deterioration of sound pressure in the high frequency range will not occur, but in the above embodiment, the number of openings is seven, because the diaphragm 5
This is to improve the sound pressure distortion caused by the non-axisymmetric vibration of the aperture, and this distortion can be improved by having an odd number of apertures instead of just seven apertures.

Further, in this embodiment, since the opening shape is radial extending in the radial direction, it is not necessary to consider the radial sound pressure distribution generated in the gap 5g at the front of the diaphragm 5, which facilitates the design.

Figures 8 to 10 show the throat opening 111a.
~117a This is a diagram showing other examples regarding the shape, and the fifth
In Figures 8 to 7, the closer the throat openings (slits) 111a to 117a are to the center of the phase equalizer, the narrower the slit width in the circumferential direction; The slit widths may be the same.

Further, the surface shape of the side wall of each of the partition walls 101 to 107 of the phase equalizer 1 in the above embodiment may be a flat surface or a curved surface, and the effect is almost the same. Note that each of the partition walls at the end of the phase equalizer 1 on the horn opening side has a sharp edge, but this is due to the propagation path of the sound wave from the end of the phase equalizer on the horn opening side to the inside of the horn inside the horn 2. The purpose is to avoid sudden changes in acoustic impedance during the
This is to avoid deterioration of characteristics due to diffraction of sound waves at the end of the horn opening of the phase equalizer.

Further, in each of the above embodiments, each partition wall 101 to 1
07 is an example of one integrally molded with a mold and one cut from a single metal material, but each of the partition walls 101 to 107 is manufactured individually, and these individually manufactured partition walls 101 to 107 are bonded to each other. A similar effect can be produced even if assembled by means such as using materials.

Here, we will discuss the point that the outer diameter of the radioactive slit is approximately the same as the outer diameter of the diaphragm, and the point that the length between adjacent openings provided in the slit is set to 1/2 or less of the wavelength.

In the configuration shown in FIG. 1, sound wave propagation in the air gap 5g in front of the diaphragm formed by the diaphragm 5 and the phase equalizer 1 will be explained. The area of
It then propagates from the throat 3 into the horn. Therefore, the positional relationship between the diaphragm 5 and the throat 3 is important.

Therefore, regarding the air gap 5g, the propagation of sound waves will be considered separately in the radial direction and the circumferential direction. First, in the radial direction, the sound waves emitted from the portion of the diaphragm facing the slit opening are guided directly to the slit opening and propagated within the horn, as shown by solid arrows in FIG. The sound waves from the diaphragm part of the phase equalizer that faces the part other than the slit opening propagate in the air gap 5g in the radial direction as shown by the broken line arrow in Figure 1, reach the slit opening, and then propagate into the horn. However, in this case, a phase difference occurs due to a time delay corresponding to the distance of propagation within the air gap 5g. Therefore, at the slit opening, the sound waves from various parts of the diaphragm are combined with a phase difference, and the characteristics deteriorate in a high frequency region with a short wavelength.

To improve this problem, it is necessary to make the length of the slit of the phase equalizer approximately the same as the outer diameter of the diaphragm.

Next, in the circumferential direction, in the case of a radial slit structure, slit openings and barrier portions are generally arranged alternately in the circumferential direction, as shown in FIG. In this case, the sound waves from the diaphragm section facing the slit opening are directly propagated from the slit opening into the horn, but the sound waves from the diaphragm section corresponding to the barrier section are propagated inside the air gap along the barrier. After reaching the slit opening, it will be propagated into the horn.

By the way, in the case of waveform synthesis, it is generally known that one of the criteria for deterioration of the synthesized waveform is that the phase difference between the waveforms to be synthesized is 1/4 wavelength or less.

Therefore, when considering the circumferential direction, the distance l between the centers of the slit openings 112 and 113 is half the length L.
As the length becomes longer than approximately 1/4 of the wavelength of the sound waves emitted from the diaphragm, the sound waves synthesized at the slit opening deteriorate due to the influence of the phase difference. In other words, the length L between the openings needs to be less than 1/2 of the wavelength of the sound wave to be reproduced.

Next, we will state that the slit has a shape in which the area of the surface perpendicular to the sound axis increases exponentially toward the exit side of the horn.

In the horn speaker of the embodiment, each slit is separated by a radial partition wall and constitutes an independent horn, so the cross-sectional area of each independent sound path from the slit opening to the phase equalizer exit is an exponential function. There is a need to change.

For example, in the case of an exponential horn, S = S ₀ ^emx S: Any distance x from the independent slit opening
Cross-sectional area at _S0 : Cross-sectional area of independent slit opening m: Change in cross-sectional area determined by flare constant.

By the way, if the cross-sectional area change in the horn does not change exponentially, the slit opening, that is,
The radiation resistance at the throat of the horn is reduced,
The output in the low frequency range of the reappearance frequency band is reduced. Therefore, the cross-sectional area is changed exponentially to improve the characteristics at low frequencies.
Its characteristic diagram is shown in FIG.

In FIG. 12, a solid line b indicates that the change in cross-sectional area is exponential, and a broken line a indicates that the change is not exponential.

The point that a plurality of independent radial slits are formed over the entire length will be described.

In a horn speaker, as described above, the sound waves radiated from each part of the diaphragm are combined once at the slit opening, so the slit opening can be thought of as a virtual diaphragm surface. It is practically difficult to ensure that the synthesized sound waves at each slit opening are the same at each slit opening, considering dimensional accuracy during assembly. Each sound wave has different characteristics. Therefore, a plurality of independent slits are formed, and the sound waves from each slit are guided to the exit of the phase equalizer without being combined in each independent sound path consisting of a phase equalizer and a horn. . Therefore, it is possible to prevent the characteristics from deteriorating in a high frequency region due to the combination of sound waves with different characteristics in the sound path.

That is, as shown in FIG. 13, the effect occurs in the high frequency range of the reproduction frequency band.

In the characteristic diagram of FIG. 13, the solid line b shows the case where each radial slit is independent, and the broken line a shows the case where each radial slit is not independent.

The point that sharp edges are provided on each partition wall at the end portion on the horn opening side will be explained.

In the embodiment, as shown in FIG. 15, phase equalizers constituting independent horns are arranged inside the horn, and the phase equalizers are shorter in length than the horns.

The propagation path of the sound waves from the slit openings 111 to 117 to the horn exit is such that the sound waves from the slit openings first propagate through independent sound paths 41 and 42 formed by phase equalizers, and then pass through the horn of the phase equalizer. The sound waves are radiatively synthesized within the horn 2 at the end E on the opening side, then propagate within the horn, and are finally radiated from the horn exit to the outside space.

When a sound wave propagates from the end E of the phase equalizer on the horn opening side into the horn located outside thereof, the change in cross-sectional area within the sound wave propagation path must be exponential. If the cross section at the end E of the horn opening of the phase equalizer and the cross section of the other horns are not configured to vary exponentially, the acoustic impedance within the horn will be disturbed at this coupling point. occurs, and the number of tones is temporarily ejected in this part, causing disturbances in the characteristics in the low frequency characteristic region.

Therefore, in order to solve this problem, sharp edges are provided on each partition wall at the end E on the horn opening side of the phase equalizer, so that the cross-sectional area inside the horn changes exponentially. It is something that exists. Furthermore, if each partition wall at the end E on the horn opening side of the phase equalizer is not linear but thick, a diffraction phenomenon occurs in the sound waves at this end, resulting in deterioration of the characteristics. In other words, when the cross-sectional area inside the horn changes suddenly, the acoustic impedance is disturbed at the changing part, causing reflection inside the horn, and as shown in Figure 14, the characteristic occurs in the low frequency range of the reproduction frequency band. is disturbed.

In the characteristic diagram of FIG. 14, the solid line b shows the case where the end portion has a sharp edge shape, and the broken line a shows the case where the end portion has a flat surface.

As shown in FIG. 15, each partition wall 101 to 107
As indicated by the nutching, the maximum circumferential width (thickness) at the outermost periphery of each partition wall is smaller (thinner) on the horn 2 open side than on the diaphragm 5 side. ), making it possible to mold it in one piece.

As mentioned above, this invention is a horn speaker equipped with a phase equalizer located in front of the diaphragm and disposed inside the horn, which has an outer diameter that is almost the same as the outer diameter of the diaphragm, and which makes the sound The area of the surface perpendicular to the axis increases exponentially toward the exit side of the horn, and the length between adjacent openings is less than 1/2 the wavelength of the upper limit frequency of the reproduction frequency range at the outermost periphery. In addition, a phase equalizer in which a plurality of independent radial slits are formed over the entire length, and a plurality of partition walls arranged radially are provided, and the maximum circumferential length width (thickness) of the partition wall is ) is shorter on the horn opening side of the phase equalizer than on the diaphragm side, and a sharp edge is provided on each bulkhead at the end of the phase equalizer on the horn opening side, making the length of the phase equalizer shorter than the length of the horn. By shortening the length, the sound pressure frequency characteristics in the high range can be significantly improved without changing the sound pressure frequency characteristics in the low range of the horn speaker, and the structure is simple. Since it is easy to integrally mold, it is possible to provide an economical phase equalizer.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view showing a conventional horn speaker, Fig. 2 is a characteristic diagram showing the relationship between frequency and sound pressure response, and Fig. 3 is a longitudinal cross-sectional view showing a part of a conventional horn speaker using another method. , FIGS. 4 to 7 are views showing an embodiment of this invention, in which FIG. 4 is a longitudinal sectional view, FIG. A plan view as seen from the side, FIG. 7 is a plan view similarly seen from the horn opening side, and FIGS. 8 to 10 are views showing other embodiments of this invention.
Fig. 8 is a perspective view showing the phase equalizer, Fig. 9 is a plan view of the phase equalizer seen from the diaphragm side, Fig. 10 is a plan view similarly seen from the horn opening side, and Fig. 11 is a plan view of this device. A plan view conceptually showing the throat part of the phase equalizer to explain the principle, FIGS. 12 to 14 are characteristic diagrams showing the relationship between frequency and sound pressure response to explain the effects of this invention, and FIG. The figure is a broken sectional view of the horn of an embodiment of this invention. In the figure, 1 is a phase equalizer, 2 is a horn, and 3
is the throat, 4 is the sound path inside the horn, 5 is the diaphragm, 5g is the air gap in front of the diaphragm, 10
1,102,103,104,105,106,
107 is a partition wall, 111, 112, 113, 11
4, 115, 116, and 117 are openings. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims for Utility Model Registration] (1) A horn speaker comprising a diaphragm, a horn, and a phase equalizer located in front of the diaphragm and inside the horn, The area of the surface perpendicular to the sound axis increases exponentially toward the exit side of the horn, and the length between adjacent openings increases at the outermost periphery. The phase equalizer has a plurality of independent radial slits that are equal to or less than 1/2 of the wavelength of the upper limit frequency of the frequency range and are formed over the entire length, and a plurality of partition walls arranged radially. The maximum circumferential width of the partition wall is made shorter on the horn opening side of the phase equalizer than on the diaphragm side, and a sharp edge is provided on each partition wall at the end of the phase equalizer on the horn opening side. A horn speaker characterized in that the length of the phase equalizer is shorter than the length of the horn. (2) The horn speaker according to claim 1, wherein the side surface of the partition wall of the phase equalizer has a curvature. (3) The horn speaker according to claim 1, wherein the side surfaces of the partition walls of the phase equalizer are flat. (4) The horn speaker according to claim 1, wherein the partition wall and the horn are integrated. (5) The horn speaker according to claim 1, wherein the plurality of partition walls are integrated.