JP2003092793A - Cylindrical enclosure type speaker system and its structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cylindrical enclosure type speaker system that employs a cylindrical enclosure whose length is a practical size of about 1m so as to satisfy a sufficiently low frequency sound in terms of both the mass and the quality. SOLUTION: The speaker system includes; a cylindrical enclosure 2 of a cylindrical shape whose one end has a speaker unit 1 and whose other end has an opening 5; and an enclosure base 3 and bottom plates 7 that support the cylindrical enclosure 2 in a substantially vertical direction. Part of the other end of the cylindrical enclosure 2 is closed by a closing ring 10 so that the opening of the cylindrical enclosure 2 has a cross sectional area smaller than that of the cylinder bottom of the cylindrical enclosure 2, a sound wave distribution member 6 is connected to the opening 5 of the other end of the cylindrical enclosure 2, distributes a sound wave emitted in the inside of the cylindrical enclosure 2 into four when the speaker unit 1 is excited, after the distributed sound wave is propagated via each propagation path space 7a, and emitted externally in a substantially horizontal direction via each external opening 4a formed to an outer circumferential edge of the enclosure base 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical casing type speaker device for faithfully reproducing a complicated waveform such as a musical sound and its structure.

[0002]

2. Description of the Related Art In a conventional cylindrical housing type speaker device, one cylindrical housing is erected vertically, a speaker unit is installed at an upper opening end, and a front surface of a diaphragm is upward. It was installed so that it would face toward, and the lower open end would be held vertically with the open end separated from the installation surface.

As a speaker unit of a cylindrical housing type speaker device of the prior art, a full range type (single cone type, coaxial 2 way and similar type) is used, and an acoustic signal of about 20 Hz to 20000 Hz which is said to be a human audible band. However, most of the problems that may occur in this case occur in the low frequency range of about 100 Hz or less, and the contents thereof are summarized in the following two points. (1) The bass that shakes the air cannot be reproduced. (2) The reproduction quality of low-pitched sound below the frequency at which the length of the cylindrical casing is ¼ wavelength is poor.

In the conventional cylindrical housing type speaker device, since the lower opening end is in the open state as described above, the acoustic impedance changes abruptly at that portion, which causes a significant deterioration of the bass reproduction quality. Was there. The lower the frequency, the more the reproduction quality deteriorates, and at the same time, the quantity of reproduced sound becomes insufficient.

The above-mentioned problem in the bass range does not occur in a cylindrical housing having an infinite length. However, in reality, a cylindrical casing of about 1 m has to be used, so that the problem in the bass range cannot be fundamentally solved.

Further, the present invention relates to a cylindrical housing type speaker device for faithfully reproducing a complicated waveform signal such as a musical sound, and as a precedent example of the same purpose, JP-A-5-56493.
Japanese Patent Application Laid-Open No. 5-145983 and Japanese Patent Application No.
Although there is a publication such as Japanese Patent No. 343026, all of them have problems in quantitative and qualitative aspects regarding reproduction of bass.

Furthermore, since a solution for enhancing the function of maintaining the plane wave state of the sound wave emitted from the rear surface of the speaker unit to the inside of the housing, which is a feature of the cylindrical housing type speaker device, has not been taken, the reproduction particularly in the middle and high-pitched sound parts. The sound quality problem was not solved sufficiently.

That is, in the cylindrical casing type speaker device,
As an important means to enhance the fidelity of the reproduced sound, the propagation of the sound wave radiated into the inside of the housing from the back of the speaker unit installed at the upper opening end of the vertically standing cylindrical housing is changed to the plane wave mode. It is necessary to keep. In order to maintain the plane wave mode of the sound wave inside the housing, it is necessary to mainly suppress the reflection of the sound wave on the inner wall surface of the housing and prevent the generation of the standing wave. In the prior art, sound absorbing and damping materials such as felt and glass wool are used to suppress the generation of unnecessary sound waves, but since the sound absorbing properties of these materials are not always satisfactory, sound absorbing materials are There was a tendency to use it excessively.

However, the sound absorbing and damping material absorbs harmful sound waves and at the same time absorbs necessary sound waves, thereby reducing sound wave energy, and when excessively used, viscous resistance action of air particles is caused. It increased remarkably and was the cause of suppressing the dynamic nature of the reproduced sound. The wall surface of the cylindrical housing is structurally hard to vibrate, which helps to improve sound quality, but on the other hand, the use of sound absorbing and damping material is excessive due to strong diametrical reflection inside the housing. Tended to become.

Even when the use of sound absorbing and damping material is reduced,
It is unavoidable to attach vibration damping and sound absorbing and damping material to the inner wall surface of the cylindrical housing, and in reality, a part of the housing is filled with sound absorbing and damping material such as glass wool or urethane cotton. There was no choice but to take a method such as hanging the sound absorbing and damping material in the longitudinal direction of the center of the housing. In such a sound absorbing method, the amount of the sound absorbing and damping material used inevitably increases, and the sound vitality tends to be lost. However, when a standing wave is generated due to the reflected wave, there is a problem that the plane wave, which is a feature of the cylindrical housing type speaker device, is destroyed, and therefore, there is no choice but to compromise while making a trade-off between them.

On the other hand, if the cross-sectional diameter of the cylindrical housing is made smaller, the frequency of the sound wave reflected on the wall surface becomes higher and the above problems are lessened. There was a problem in that the volume of the sound was reduced and the lowest range could not be reproduced.

A first object of the present invention is to solve the above problems, and to propagate a sound wave radiated into the inside of the housing from the back surface of a speaker unit attached to the upper open end of a vertically standing cylindrical housing. To provide a cylindrical housing type speaker device capable of maintaining a flat wave mode and more faithfully reproducing a complicated waveform such as a musical sound, and a structure thereof.

A second object of the present invention is to solve the above problems, and by using a cylindrical casing having a length of less than 2 m and a practical length of about 1 m, a sufficiently low bass (for example, 100 to 30 Hz). (EN) It is to provide a cylindrical casing type speaker device and a structure thereof capable of reproducing a bass sound in the lowest sound region) in a state in which both the quality and the quantity are satisfactory.

A third object of the present invention is to solve the above-mentioned problems, and in a cylindrical housing type speaker device, regardless of the cross-sectional diameter of the housing, from low-pitched sound to high-pitched sound area without using a lot of sound absorbing and damping material. It is an object of the present invention to provide a cylindrical casing type speaker device capable of maintaining a plane wave and its structure.

[0015]

A cylindrical casing type speaker device according to a first aspect of the present invention includes a cylindrical casing having a speaker unit at one end and an opening at the other end, and the cylindrical casing. In a cylindrical housing type speaker device provided with a supporting means for supporting the cylindrical housing so as to stand substantially vertically, an opening of the cylindrical housing has a cross-sectional area smaller than a cross-sectional area of a bottom surface of the cylinder housing. A part of the other end of the cylindrical housing is closed so as to have a sound wave radiated into the inside of the cylindrical housing when the speaker unit is excited and connected to the opening at the other end of the cylindrical housing. And a sound wave distributing means for distributing the sound wave into a plurality of N sound waves, and a propagation path having substantially the same cross-sectional area. After propagating the distributed plurality N sound waves through the respective propagation paths, , Through the external openings, radiate outward in a substantially horizontal direction. N propagation means, the distance from the opening at the other end of the cylindrical housing to the external opening of each of the propagation means through the sound wave distributing means, and the opening at the other end of the cylindrical housing. The resonance frequency of Helmholtz, which is determined based on the cross-sectional area and the volume of the cylindrical housing, is set to substantially match the lowest resonance frequency of the speaker unit.

In the above-mentioned tubular casing type speaker device, the area obtained by dividing the cross-sectional area of the opening at the other end of the tubular casing by the plurality N is substantially equal to the cross-sectional area of the propagation path of each propagation means. It is characterized in that they are formed to match.

Further, in the above-mentioned cylindrical casing type speaker device, the sound wave distributing means has a surface for distributing sound waves.
It is characterized by including a sound wave reflection preventing member.

Further, in the above-mentioned tubular casing type speaker device, the tubular units are housed in the tubular casing so that the longitudinal direction of each tubular capillary is substantially parallel to the longitudinal direction of the tubular casing, and the speaker unit is excited. It is characterized by further comprising a plurality of tubular capillaries for maintaining the acoustic waves radiated inside the tubular casing as substantially plane waves.

A tubular casing type speaker device according to a second aspect of the invention has a tubular casing having a speaker unit at one end and an opening at the other end, and the tubular casing in a substantially vertical direction. In a cylindrical housing type speaker device having a supporting means for supporting it so as to stand upright, the longitudinal direction of each cylindrical thin tube is housed in the cylindrical casing so as to be substantially parallel to the longitudinal direction of the cylindrical casing, It is characterized in that a plurality of tubular capillaries are provided for substantially maintaining a sound wave radiated inside the tubular housing as a plane wave when the speaker unit is excited.

Further, in the above-mentioned cylindrical casing type speaker device, each of the cylindrical capillaries is a cylindrical capillarity, and the diameter of each of the cylindrical capillaries is shorter than the upper limit wavelength of the fundamental tone of the plane wave to be maintained, and is to be maintained. Is set to be longer than the upper limit wavelength of the third harmonic of the plane wave.

Further, the above-mentioned tubular casing type speaker device is characterized by further comprising a sound absorbing and damping material provided between each of the tubular capillaries and the cylindrical housing.

According to a third aspect of the present invention, there is provided a cylindrical casing type speaker device having a structure in which a speaker unit is provided at one end and an opening is provided at the other end, and the cylindrical casing is substantially perpendicular to the cylindrical casing. In a structure of a cylindrical housing type speaker device provided with a supporting means that stands upright in a direction, an opening of the cylindrical housing has a cross-sectional area smaller than a cross-sectional area of a bottom surface of the cylindrical housing. A part of the other end of the cylindrical housing is closed and connected to an opening at the other end of the cylindrical housing to generate a plurality of sound waves radiated inside the cylindrical housing when the speaker unit is excited. The sound wave distributing means for distributing the sound waves into N sound waves and the propagation paths having substantially the same cross-sectional areas, respectively, and after propagating the distributed N sound waves through the respective propagation paths, A plurality of N radiating outward in a substantially horizontal direction through the external opening And a distance from the opening at the other end of the cylindrical housing to the external opening of each of the propagation means via the sound wave distributing means, and the disconnection of the opening at the other end of the cylindrical housing. The resonance frequency of Helmholtz, which is determined based on the area and the volume of the cylindrical housing, is set to substantially match the lowest resonance frequency of the speaker unit.

Further, in the structure of the above-mentioned tubular housing type speaker device, the area obtained by dividing the cross-sectional area of the opening at the other end of the tubular housing by the plurality N is substantially equal to the cross-sectional area of the propagation path of each propagation means. It is characterized in that they are formed so as to coincide with each other.

Further, in the structure of the above-mentioned tubular casing type speaker device, the sound wave distributing means is provided with a sound wave reflection preventing member on a surface for distributing sound waves.

Furthermore, in the structure of the above-mentioned cylindrical casing type speaker device, the cylindrical unit is housed in the cylindrical casing so that the longitudinal direction of each cylindrical capillary is substantially parallel to the longitudinal direction of the cylindrical casing, and the speaker unit is accommodated. It is characterized by further comprising a plurality of cylindrical thin tubes for substantially maintaining a plane wave of the sound wave radiated inside the cylindrical housing when excited.

In the structure of the cylindrical housing type speaker device according to the fourth invention, a cylindrical cylindrical housing having a speaker unit at one end and an opening at the other end, and the cylindrical housing substantially perpendicular to each other. In a structure of a cylindrical housing type speaker device provided with a supporting means for standing upright in a direction, the longitudinal direction of each tubular capillary in the tubular casing is substantially parallel to the longitudinal direction of the tubular casing. And a plurality of tubular capillaries for substantially maintaining the acoustic waves radiated inside the tubular housing as plane waves when the speaker unit is excited.

Further, in the structure of the above-mentioned tubular housing type speaker device, each of the tubular capillaries is a cylindrical capillary, and the diameter of each of the tubular capillaries is shorter than the upper limit wavelength of the fundamental tone of the plane wave to be maintained and maintained. It is characterized in that it is set to be longer than the upper limit wavelength of the third harmonic of the plane wave to be attempted.

Further, the structure of the above-mentioned cylindrical casing type speaker device is characterized by further including a sound absorbing and damping material provided between each of the cylindrical thin tubes and the cylindrical casing.

[0029]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment> FIG. 1 is a perspective view showing the structure of a cylindrical housing type speaker device according to a first embodiment of the present invention, and FIG. 2 is a cylindrical housing type speaker device of FIG. It is a front view. 3 is a vertical cross-sectional view taken along the line BB 'of FIG. 1, and FIG. 4 is a cross-sectional view taken along the line AA' of FIG.

The cylindrical housing type speaker device according to the first embodiment is, as shown in FIGS. 1 to 4, a cylindrical cylindrical housing having a speaker unit 1 at one end and an opening 5 at the other end. The body 2 and the housing base 3 and the bottom plate 7, which are supporting means for supporting the cylindrical housing 2 so as to stand in a substantially vertical direction, are provided, and the opening 5 of the cylindrical housing 2 has the opening 5. A part of the other end of the cylindrical housing 2 having a cross-sectional area smaller than that of the bottom surface of the cylinder 2 (preferably having a cross-sectional area of about 1/2 of the effective area of the diaphragm of the speaker unit 1). Is closed by a closing ring 10, and a sound wave distribution member 6 formed by combining two flat plates in a cross shape is conductively connected to the opening 5 at the other end of the cylindrical housing 2, and when the speaker unit 1 is excited, the cylindrical housing. The sound wave radiated inside the body 2 is divided into 4 and Four propagation path spaces 7a extending from the sound wave distributing member 6 at right angles to each other and having substantially the same cross-sectional areas are formed between the housing base portion 3 and the bottom plate 7 to distribute the distributed sound waves. After being propagated respectively through the propagation path space 7a, it is radiated to the outside in a substantially horizontal direction through each external opening 4a formed at the outer peripheral edge portion of the housing base portion 3. There is. Here, the distance from the opening 5 at the other end of the cylindrical housing 2 to the external opening 4 via the sound wave distribution member 6 and each propagation path space 7a, and the disconnection of the opening 5 at the other end of the cylindrical housing 2. The Helmholtz resonance frequency, which is determined based on the area and the volume of the cylindrical housing 2, is set to substantially match the lowest resonance frequency of the speaker unit 1. Furthermore, the area obtained by dividing the cross-sectional area of the opening 5 at the other end of the cylindrical housing 2 by the distribution number = 4 is formed so as to substantially match the cross-sectional area of each propagation path space 7a.

The object of the cylindrical casing type speaker device of the first embodiment according to the present invention is the drawback of the cylindrical casing type speaker device of the prior art (1) The reproduction level of the low frequency sound which is close to the audible limit is extremely low and almost no sound is heard. It is an object of the present invention to provide a technical means for solving the phenomenon of non-availability, and (2) the phenomenon that low frequencies close to the reproduction limit are greatly affected by the drastic change in the acoustic impedance in the lower opening and the fidelity is significantly impaired.

In general, the cylindrical housing type speaker device has a structure in which the area of the diaphragm of the speaker unit 1 and the cross sectional area of the cylindrical housing 2 are substantially equal to each other, so that the sound wave radiated from the back surface of the diaphragm is generated. It does not expand and diffuse in the lateral direction, and travels downward in the cylindrical housing 2 in the state of a plane wave. Therefore, when the length of the cylindrical housing 2 is sufficiently long, the acoustic load applied to the back surface of the diaphragm becomes constant regardless of the frequency, and a reproduced sound with high fidelity can be obtained from low to high frequencies. For example, a practical reproduction band is 30 to 2
When set to 0000 Hz, the length of the cylindrical casing is equal to or more than ¼ wavelength of 30 Hz, that is, 344 m / (30 × 4) = 2.8.
If the sound velocity is 7 m or more (however, the sound velocity is 344 m), the sound waves in the above area can be faithfully reproduced with sufficient sound pressure.

However, in a generally used cylindrical housing type speaker device having a length of about 1 m, even if an attempt is made to reproduce a high quality bass, the limit is about 80 Hz and the bass is lower than that. It was unavoidable that both quantity and quantity deteriorate. Since this has a structure in which the lower opening end of the cylindrical housing 2 is opened as described above,
This is because the acoustic impedance changes abruptly at that portion, and a sound wave reflection phenomenon occurs. This effect becomes more remarkable as the sound wave has a longer wavelength, which is a factor of lowering the volume of low-pitched sound and deteriorating the sound quality.

In the first embodiment according to the present invention, in order to prevent such a phenomenon from occurring, the cylindrical casing 2
The opening end of the lower part of the is partially closed by a closing ring 10. If all of the lower open ends of the cylindrical housing 2 are closed, the cylindrical housing 2 is in a hermetically closed state and the back surface pressure of the diaphragm in the low sound range increases, so that the minimum resonance frequency f ₀ of the speaker unit 1 increases. , It is not possible to reproduce to the desired low frequency range around 30 Hz. In order to suppress the increase of the minimum resonance frequency f ₀ of the speaker unit 1, there is a method of increasing the cross-sectional area of the cylindrical housing 2 to increase the volume of the housing. Rapidly expands in the lateral direction, and the plane wave that is a characteristic of the cylindrical housing 2 collapses, making it impossible to obtain a reproduced sound with high fidelity.

In the first embodiment according to the present invention, while maintaining the mode in which the sound wave radiated from the back surface of the diaphragm travels in the state of a plane wave along the wall surface of the cylindrical housing 2, the other lower end of the cylindrical housing 2 is maintained. In order to prevent an increase in the minimum resonance frequency f ₀ caused by the reflection of sound waves or the increase in pressure inside the housing,
The structure is provided with a closing ring 10 that forms the opening 5.

The shape of the opening 5 is preferably circular in order to minimize the collapse of the plane wave which is surrounded by the wall surface of the cylindrical housing 2 and progresses, but other shapes such as a square, a rectangle and a triangle. But there is no problem in practical use. This first
In the above embodiment, the opening 5 has a square shape in order to radiate the radiation in four directions.

Next, referring to FIGS. 1 to 4,
The structure of the cylindrical housing type speaker device according to the present embodiment will be described in detail below.

As shown in FIGS. 1 and 2, the speaker unit 1 is provided at one end of the upper part of the cylindrical housing 2 so that the sound wave from the speaker unit 1 from the front surface of the diaphragm is radiated upward. On the other hand, the other end of the cylindrical case 2 is connected to a cylindrical base case 3 having a cross section larger than the cross section of the bottom surface of the cylindrical case 2 and a bottom plate 7 adhered to the lower part thereof. The housing base portion 3 and the bottom plate support the cylindrical housing 2 so as to stand in a substantially vertical direction.

In FIG. 3, a closing ring 10 is fitted to the other end of the lower portion of the cylindrical housing 2 to close a part thereof, and the circular outer diameter of the closing ring 10 is equal to the inner diameter of the cylindrical housing 2. Equally, a square opening 5 is formed in the central part of the closing ring 10. Also, as will be described later, in order to satisfy the condition of the Helmholtz resonance frequency,
A square tube-shaped conduit tube 11 extending from the opening 5 toward the inside of the cylindrical housing 2 is provided. Further, immediately below the center of the opening 5, a square pillar-shaped propagation path space 6a surrounded by the housing base 3 and the bottom plate 7 is formed. In the propagation path space 6a, as shown in FIGS. As shown, the sound wave distribution member 6 formed by combining two flat plates in a cross shape has two square flat openings 5.
It is provided so as to be located on the diagonal line of and be erected from the bottom plate 7. The sound wave distributing member 6 is radiated into the inside of the cylindrical housing 2 when the speaker unit 1 is excited, and then propagates as a plane wave inside the cylindrical housing 2 through the propagation path space 11a in the conducting tube 11. The sound wave that has reached the opening 5 is divided into four. Therefore, the propagation path space 6 a is divided into four by the sound wave distribution member 6.

The four-divided propagation path spaces 6a extend from the sound wave distributing member 6 at right angles to each other and have substantially the same sectional areas (rectangular longitudinal section; having height H2). The path spaces 7a are conductively connected to each other, and each of the propagation path spaces 7a is formed between the housing base 3 and the bottom plate 7. An external opening 4 formed by opening a part of the housing base portion 3 is formed at an end of each propagation path space 7a. The four external openings 4 also correspond to each propagation path space 7a. Then, they are formed at the outer edge portions of the housing base portion 3 and at right angles to each other.

Here, the cross-sectional area S of the opening 5 is substantially equal to four times the cross-sectional area of each of the isosceles triangular propagation path spaces 6a divided by the sound wave distributing member 6, and the opening is The cross-sectional area S of 5 is preferably four times the cross-sectional area of the rectangular vertical cross section of each propagation path space 7a and each external opening 4.
It is formed so as to be equal to four times the cross-sectional area of the vertical cross section.

On the upper surface of the bottom plate 7 located immediately below each propagation path space 6a, in order to prevent the sound waves propagated as plane waves from being totally reflected by the bottom plate 7, sound wave reflection prevention such as felt or deer skin is prevented. The member 12 is formed. As a result, the sound waves are smoothly distributed to each propagation path space 7a,
It can be conducted.

When the speaker unit 1 is excited in the cylindrical housing type speaker device configured as described above,
The sound wave emitted from the front surface of the diaphragm of the speaker unit 1 is emitted upward, and the sound wave is emitted omnidirectionally over substantially the entire room in which the cylindrical housing type speaker device is installed. On the other hand, the sound wave radiated from the rear surface of the diaphragm of the speaker unit 1 is radiated into the cylindrical housing 2 and then
It propagates as a plane wave inside the cylindrical housing 2 and reaches the opening 5 via the propagation path space 11a in the conducting tube 11, and at this time, the sound wave distribution member 6 is guided to the opening 5 as shown by an arrow 100. The sound wave that arrived is divided into four. Then, the four-divided sound waves are transmitted to each propagation path space 6 as indicated by an arrow 100.
After propagating from a through each propagation path space 7a, it is radiated to the outside in a substantially horizontal direction through each external opening 4 formed at the outer peripheral edge of the housing base 3.

Further, setting conditions in the cylindrical casing type speaker device according to the present embodiment will be described.

The low-pitched sound range can be expanded by providing the opening 5 with a structure having a certain length (hereinafter referred to as a conduction propagation path). This idea is based on prior art document 1 “George L. Augspurger of Northwestern
University, "Loudspeakerson Damped Pipes", Journa
l of Audio Engineering Society, Vol. 48, No. 5, May
2000 "paper, Vented pip (Vented pip
e) (corresponding to the cylindrical housing having the conducting tube in the present embodiment) is described as capable of extending the bass range, but the reason and theory thereof are not described. The basis of this idea is based on Helmholtz's resonance theory, and many box-shaped speaker boxes that apply this theory have been put to practical use. Although the so-called phase inversion type is used, the purpose is to expand the low frequency range, and
It is not intended to extend the bass range together with the suppression of low-quality sound waves caused by the disturbance of the plane wave traveling in the cylindrical casing 2 in the lower portion of the casing as in the above embodiment.

Even when the opening 5 is opened in the lower part of the cylindrical housing 2 and opened at a certain length, the acoustic impedance changes at the open end, and a sound wave reflection phenomenon occurs. However, when the resonance phenomenon occurs, the sound pressure below the resonance frequency is rapidly attenuated, so that the energy of the sound wave reflected by the change in the acoustic impedance outside the housing is significantly reduced, and the sound quality deterioration can be suppressed. I can.

In this embodiment, the sound wave radiated from the rear surface of the diaphragm of the speaker unit 1a is the cylindrical housing 2a.
Along the wall surface of the housing, the surface wave proceeds toward the housing base portion 3 while maintaining a plane wave state. An opening 5 of a conducting tube 11 for radiating sound waves to the outside is provided at the center of the housing base 3. The area S of the opening 5 is preferably about ½ of the effective area of the diaphragm of the speaker unit 1, but is finally determined preferably by frequency measurement and hearing. In addition, when the length L of the conduction propagation path described later is insufficient, the length of the conduction tube 11 in the longitudinal direction may be extended so as to further extend inside the cylindrical housing 2.

The conduction propagation path extends downward from the opening 5 through the central portion of the housing base portion 3, and the sound wave distribution member 6 is provided.
The base plate 7 bends in four directions in the front, rear, left, and right directions at an angle of 90 degrees and divides and extends, and is opened to the outside through an external opening 4 provided at the outer peripheral edge of the housing base 3. Here, the cross-sectional area of the external opening 4 is preferably S / 4. In the present embodiment, the conduction propagation path means the conduction tube 1
From the inner side end of the cylindrical housing 2 of No. 1 to the propagation path space 11a in the conducting tube 11, the propagation path space 6a of the sound wave distribution member 6,
And the propagation path of the sound wave through the propagation path space 7a to the external opening 4.

The length L of the conduction propagation path can be determined by referring to FIG.

## EQU1 ## L = L1 + L2, and the space of the conduction propagation path having the length L and the space of the volume V of the cylindrical housing 2a cause the Helmholtz resonance phenomenon. The resonance frequency F ₀ is represented by the following formula according to the Helmholtz theory formula.

[0051]

[Equation 2]

Here, S is the cross-sectional area of the opening 5, and c
Is the speed of sound, and c = 34400 cm / sec.

[0053]

EXAMPLE The resonance frequency F ₀ in the above _equation 2 is set to an approximate frequency that substantially matches the lowest resonance frequency of the speaker unit 1 used in the present speaker device. The following table shows the numerical values of the prototype according to the first embodiment of the present invention.

[0054]

[Table 1] ――――――――――――――――――――――――――――――――――― (1) Internal volume V of the cylindrical housing 2 = 45 liters (2) Length of cylindrical housing 2 = 100 cm (3) Nominal aperture of speaker unit = 20 cm (4) Effective area of diaphragm of speaker unit 1 = 206 cm ² (5) Minimum resonance of speaker unit 1 Frequency f ₀ = 40 Hz (6) Cross-sectional area of opening 5 a = 206 × 0.5 = 103 cm ² (7) Length of conduit 11 = 35 cm (8) Resonance frequency F ₀ = 44 Hz ――――――― ――――――――――――――――――――――――――――

With respect to the expansion of the bass reproduction area, which is the first object of the present invention, in the cylindrical housing type speaker device of about 1 m, the bass which cannot be obtained by the conventional lower open type speaker device is made to have the above structure. Made possible to play by.

Another object of the present invention is to provide a sound wave in the lowest sound region generated by a drastic change in impedance when a sound wave in a plane wave state peculiar to a cylindrical housing is radiated from the lower part of the speaker housing to the outside. Although it is to suppress the sound quality deterioration due to the reflection, by using the above structure, for example, in the case of a prototype, a frequency level below the resonance frequency F ₀ (44 Hz) of the speaker device is 18 dB / o.
It can be sharply attenuated by ct, and the occurrence of the above phenomenon can be effectively prevented.

As described above, in this embodiment, a part of the lower end of the cylindrical housing 2 is closed by the closing ring 10, and the effective area of the diaphragm of the speaker unit 1 is about 50 at the center thereof. The opening 5 having an area of 5% is formed. The opening 5 is an opening in the housing for a conduction propagation path for releasing a sound wave emitted from the back surface of the diaphragm of the speaker unit 1 attached to the upper part of the cylindrical housing 2 to the outside of the cylindrical housing 2. The sound waves travel downward from there, and are distributed by the sound wave distribution member 6 in the housing base portion 4 into four, and are provided in the front, rear, left, and right directions toward the external opening 4 at the position where they hit the bottom plate 7. It is guided to the individual propagation path spaces 7a and radiated in the horizontal direction to the outside from each external opening 4 provided at the outer peripheral edge of the housing base 3. Where 4
The sound waves emitted from the individual outer openings 4 are substantially 360
Directionality, that is, omnidirectionality, and is in the same mode as the sound wave radiated upward from the front surface of the diaphragm of the speaker unit 1. The cross-sectional area of each of the four propagation path spaces 7a and the external opening 4 is ¼ of the cross-sectional area of the lower end opening 5 of the cylindrical housing 2, and the cross-sectional area from the upper opening of the conduit 11 to the opening 5 and each propagation path. There is no change in area up to each external opening 4 through the space 7a.

In this embodiment, the cross-sectional area of the propagation path space = the cross-sectional area S of the opening 5 of the conducting tube 11, the length L of the propagation path space = L1 + L2, and the set value of the internal volume V of the cylindrical housing 2 are set. Can cause Helmholtz resonance. Therefore, the resonance frequency F ₀ can be set to a desired value by setting the three values to appropriate values according to the formula (equation 2) of the same theory. This makes it possible to relatively easily obtain a bass characteristic close to the desired value. Further, since the energy of the sound wave having the resonance frequency F ₀ or less is rapidly attenuated at about 18 dB / oct, the disturbance due to the reflection of the low frequency sound wave below that is suppressed, and the excellent acoustic characteristics of the cylindrical housing 2 can be maintained. This makes it possible to obtain high quality reproduced sound.

Further, in the speaker device of which the lower opening is opened, the housing base portion 3 cannot be physically made large in order to suppress sound quality deterioration, and it is difficult to secure the stability of the cylindrical housing 2 to be erected. However, the structure of the first embodiment according to the present invention makes it possible to form a highly stable housing base portion 3 having a diameter of about 50% of the length of the cylindrical housing 2. It was Further, if necessary, the length L of the conduction propagation path and the area S of the opening 5 can be changed based on a mathematical expression to make the housing base 3 of any size.

Since the sound wave radiated from the speaker device according to the first embodiment described above is omnidirectional, the conduction propagation path in the housing base portion 3 is open in the front, rear, left and right directions as described above. It is desirable, but one direction, two directions,
There are no problems in practical use even in three directions. Further, the distribution opening may be performed in five or more directions.

<First Modification> FIG. 5 is a longitudinal sectional view of a cylindrical housing type speaker device according to a first modification corresponding to FIG. 3, and FIG. 6 is a cylindrical housing type speaker of FIG. Of the device,
FIG. 5 is a transverse cross-sectional view of the CC ′ plane corresponding to FIG. 4. This first
The modified example is an example in which the conduction propagation path is opened in two directions, and is characterized by including a sound wave distribution member 106 that distributes a sound wave into two. Hereinafter, differences from the first embodiment will be described in detail.

In FIG. 5, a square conducting tube 111 is conductively connected to the opening 5 at the other lower end of the cylindrical housing 2 in the downward direction, and a propagation path space 111a is formed in the conducting tube 111. It is formed. The case base 103 is connected to the lower portion of the conducting tube 111, and a square column-shaped propagation path space 103a extending in the vertical direction is formed in the center of the case base 103. Further, right below the center of the opening 5 and directly below the propagation path space 103a, in the space surrounded by the housing base 103 and the bottom plate 7, a triangular roof-shaped sound wave distribution member 106 is provided on the bottom plate 7. It is provided. The ridge portion of the triangular roof of the sound wave distribution member 106 is provided so as to pass through the central portions of the two sides of the opening 5 that face each other and divide the opening 5 into two sections. The sound wave distributing member 106 is radiated into the inside of the cylindrical housing 2 when the speaker unit 1 is excited, and then propagates as a plane wave inside the cylindrical housing 2 to propagate a propagation path space in the opening 5 and the conducting tube 111. The sound wave that has reached the propagation path space 106a between the housing base portion 3 and the sound wave distribution member 106 is split into two via 111a. That is, the propagation path space 106a is divided into two.

Each of the two divided propagation path spaces 106a extends from the sound wave distributing member 106 at an angle of 180 degrees with each other and has substantially the same cross-sectional area (rectangular longitudinal section; height H2a). Propagation path space 10 having
7a is conductively connected to each of the propagation path spaces 10
7 a is formed between the housing base portion 103 and the bottom plate 107. An external opening 104 formed by opening a part of the housing base 103 is formed at an end of each propagation path space 107a. The two external openings 104 also correspond to each propagation path space 107a. Then, they are formed at the outer edge portions of the housing base portion 103 and at positions of an angle of 180 degrees with respect to each other. The inside angle of the housing base 103 facing the roof surface of the sound wave distribution member 106 is chamfered 103b.
The cross-sectional area of the conduction propagation path is formed to be substantially the same throughout the conduction propagation path.

Here, the cross-sectional area S of the opening 5 is preferably twice the rectangular cross-sectional area of each of the two propagation path spaces 106, and the cross section of the rectangular vertical cross section of each propagation path space 107a. It is formed to be equal to twice the area and twice the cross-sectional area of the vertical cross section of each external opening 104.

On the upper surface of the roof portion of the sound wave distribution member 106, in order to prevent the sound wave propagated as a plane wave from being totally reflected, a sound wave reflection preventing member 1 such as felt or deer bark.
12 are formed. As a result, the sound wave can be smoothly distributed and conducted to each propagation path space 107a.

In the cylindrical housing type speaker device according to the first modified example having the above-described structure, when the speaker unit 1 is excited, the sound wave emitted from the front surface of the diaphragm of the speaker unit 1 is emitted upward. The sound waves are omnidirectionally radiated over almost the entire room in which the cylindrical housing type speaker device is installed. On the other hand, the sound wave radiated from the rear surface of the diaphragm of the speaker unit 1 is radiated to the inside of the cylindrical housing 2, then propagates as a plane wave inside the cylindrical housing 2, and propagates from the opening 5 into the conducting tube 111. Route space 11
1a to reach the propagation path space 106a, and at this time, the sound wave distribution member 106, as shown by an arrow 110,
The reached sound wave is divided into two. Then, the two-divided sound waves are transmitted to each propagation path space 10 as indicated by an arrow 110.
After propagating from 6a through each propagation path space 107a, it is radiated to the outside in a substantially horizontal direction through each external opening 104 formed at the outer peripheral edge of the housing base 103.

In the first modification constructed as described above, the length L of the propagation path space is L = L11 + L12 + L13.
By setting so as to satisfy the Helmholtz equation (Equation 2) by using, it is possible to obtain the same effect as the effect of the first embodiment described above.

<Second Modification> FIG. 7 shows a cylindrical housing type speaker device according to a second modification, which corresponds to FIG.
It is a cross-sectional view of the C'plane. In this second modified example, FIG.
As shown in FIG. 4, compared with the first embodiment of FIG. 4, a sound absorbing and damping material 13 having a thickness of, for example, 1 cm, made of felt for absorbing sound waves is attached to the inner peripheral surface of the cylindrical housing 2. It is characterized by being attached. Thereby, it is possible to prevent the sound wave radiated in the cylindrical housing 2 from being reflected on the inner peripheral surface of the cylindrical housing 2 and breaking the plane wave, and the plane wave up to a frequency shorter than the cross-sectional diameter of the cylindrical housing 2. The effect that can be maintained can be obtained.

<Third Modification> FIG. 8 shows a cylindrical housing type speaker device according to a third modification, which corresponds to FIG.
It is a cross-sectional view of the C'plane. In this third modified example, FIG.
As shown in FIG. 6, compared with the first modification of FIG. 6, a sound absorbing and damping material 113 having a thickness of 1 cm, for example, made of felt for absorbing sound waves is attached to the inner peripheral surface of the cylindrical housing 2. It is characterized by being attached. Thereby, it is possible to prevent the sound wave radiated in the cylindrical housing 2 from being reflected on the inner peripheral surface of the cylindrical housing 2 and breaking the plane wave, and the plane wave up to a frequency shorter than the cross-sectional diameter of the cylindrical housing 2. The effect that can be maintained can be obtained.

<Second Embodiment> FIG. 9 is a partially cutaway perspective view showing the structure of a cylindrical housing type speaker device according to a second embodiment of the present invention. FIG. 10 is a sectional view taken along line D- of FIG. It is a cross-sectional view of the D'plane. The cylindrical housing type speaker device according to the second embodiment is different from the first embodiment shown in FIG.
A sound absorbing and damping material 13 made of felt, for example, having a thickness of 1 cm, is attached to the inner peripheral surface of the cylindrical housing 2, and the speaker unit 1 is attached to the inner peripheral surface of the sound absorbing and damping material 13. 7 cylindrical capillaries 20 for maintaining the sound wave radiated from the back surface of the cylindrical housing 2 in the plane wave mode are filled and housed so that the longitudinal direction thereof is substantially parallel to the longitudinal direction of the cylindrical housing 2. It has a feature. The other configuration is similar to that of the first embodiment. In addition,
The speaker unit 1 includes a diaphragm 1a and a magnet 1b.

In this embodiment, by attaching the sound absorbing and damping material 13, it is possible to prevent the sound wave radiated in the cylindrical casing 2 from being reflected on the inner peripheral surface of the cylindrical casing 2 and breaking the plane wave. Therefore, the plane wave can be maintained up to the frequency of the wavelength shorter than the cross-sectional diameter of the cylindrical housing 2. In addition, in the present embodiment, the sound absorbing and damping material 13 is not always essential and may not be provided.

As shown in FIG. 10, seven cylindrical thin tubes 20 for maintaining a plane wave are formed in the cylindrical housing 2 so as to be in contact with each other. The vibrating member 13 is further bonded and fixed with an adhesive, and the diameter of one cylindrical thin tube 20 is about one third of the inner diameter of the cylindrical housing 2. Further, as shown in FIG. 9, each cylindrical thin tube 20 has a length L ₁₀ of the cylindrical housing 2.
Has a length L ₂₀ that is about ⅔ to about 3/4 of that of the speaker unit 1 and has a predetermined distance L ₁₁ so as not to contact the magnet 1b of the speaker unit 1, while the lower part has a cylindrical housing 2 Is mounted with a predetermined distance L ₁₂ (details will be described later) from the bottom of the. Here, the distance L ₁₂ is preferably about 1/3 to about 1/4 of the length L ₁₀ of the cylindrical housing 2.

Here, the inner peripheral surface and the outer peripheral surface of each cylindrical thin tube 20 are preferably smooth surfaces in order to smooth the progress of the parallel wave, that is, to prevent the progress of the parallel wave. A traveling wave that is a parallel wave of a part
The outer peripheral surface may be a rough surface to some extent in consideration of traveling in the inner peripheral surface of 0. Further, substantially perpendicularly to the inner peripheral surface and the outer peripheral surface of each cylindrical thin tube 20 (horizontal direction,
That is, since it is necessary to absorb the reflected wave or standing wave incident in the lateral direction, it is preferable to form each cylindrical thin tube 20 with a material that easily converts the acoustic energy into heat energy. Is a material in which fibers are entangled and wound in 3 to 5 layers, and has a sound absorbing property to reflected waves or standing waves. As the paper of the above-mentioned material, for example, drawing paper made by Daishowa Paper Manufacturing (125 k in the 46th edition)
g / 1000 sheets; for example, a thickness of 0.2 to 0.3 mm) is suitable. Alternatively, each cylindrical thin tube 20 may have a structure in which multiple-rolled paper is surrounded by a single closed paper tube, and other materials may be used as long as they have equivalent performance.

Next, the maximum diameter and the minimum diameter of each cylindrical thin tube 20 will be described below. The maximum diameter (upper limit value) and the minimum diameter (lower limit value) of the inner diameter of each cylindrical thin tube 20 are determined by the maximum frequency (upper limit) of the plane wave to be maintained. According to Olson's singing voice and the fundamental frequency band table of musical instruments, the upper limit of the fundamental tone is 1
The number of 000 Hz musical instruments is 70% of the total. If the upper limit of the fundamental tone is further set to 4000 Hz, it reaches 95% of the whole. The instrument with the highest fundamental pitch is a pipe organ, about 8
It is 000 Hz.

Here, if the upper limit of the fundamental tone is 4000 Hz, the wavelength of the plane wave of the upper limit of the fundamental tone is 34400 ÷ 400.
Since 0 = 8.6 cm, the maximum diameter (inner diameter) of each cylindrical thin tube 20 is preferably set shorter than the upper limit wavelength of the fundamental wave of the fundamental tone. This is because a sound wave having a frequency shorter than the cross-sectional diameter of the cylindrical thin tube 20 is likely to be reflected on the inner wall surface of the cylindrical housing 2 and it becomes difficult to maintain a plane wave. On the other hand, the fundamental tone is 120% at the third harmonic of the instrument with 4000 Hz
Since it is 00 Hz, the wavelength of the plane wave at the upper limit of the third harmonic is
34400 ÷ 12000 = 2.9 cm, and the minimum diameter (inner diameter) of each cylindrical thin tube 20 is preferably set longer than the upper limit of the wavelength of the plane wave of the third harmonic. As a result, it is possible to propagate a plane wave including most high frequency components. By setting the maximum diameter (upper limit value) and the minimum diameter (lower limit value) of the inner diameter of each of the cylindrical thin tubes 20 described above, the cylindrical housing sufficiently contains the frequency component of the plane wave to be maintained and substantially maintains the plane wave. 2 can be propagated.

Further, the reason why a space having a length L ₁₂ is provided between each cylindrical thin tube 20 and the housing base portion 3 in the lower portion of the cylindrical housing 2 will be described below.

When the lower end of the cylindrical thin tube 20 is extended to the bottom of the cylindrical casing 2, when the Helmholtz resonance phenomenon occurs, the cylindrical casing 2 is opened from the opening of the conducting pipe 11 at the bottom. Since the sound pressure of the sound wave that expands and diffuses rapidly toward the inner tube wall is attenuated on the wall surface of each cylindrical thin tube 20, the resonance phenomenon is suppressed and the bass level is lowered. In an extreme case, when the cylindrical thin tube 20 located at the center of the plurality of cylindrical thin tubes 20 covers the opening of the conducting tube 11, the resonance phenomenon hardly occurs. On the other hand, each cylindrical thin tube 20
If the length of is shortened and the lower space is taken too wide, the maintenance of the plane wave becomes incomplete and the sound quality deteriorates. According to the results of experiments conducted by the inventor, the compromise was obtained by taking the lower end of the cylindrical capillary tube 20 from the lowermost portion of the cylindrical housing 2 to a height of about 25%.

In the cylindrical housing type speaker device according to the second embodiment configured as described above, the sound wave radiated from the back surface of the speaker unit 1 passes through the internal space 20a of each cylindrical capillary 20 and is in the cylindrical housing. Propagate to the bottom of 2. Since the inner diameter of each cylindrical thin tube 20 is about one third of the inner diameter of the cylindrical housing 2, the maximum frequency of the plane wave that each cylindrical thin tube 20 can maintain is about three times the maximum frequency that the cylindrical housing 2 can maintain. . A space 21 formed between each cylindrical thin tube 20 and the cylindrical casing 2 and a space 2 formed between the cylindrical thin tubes 20.
For plane waves passing through 2, it is possible to maintain even higher frequencies.

Although the above description relates to the maintenance of the plane wave by the cylindrical thin tube 20, the effect of the cylindrical thin tube 20 in the present embodiment is that the sound absorbing and damping material 13 attached to the inner wall surface of the cylindrical housing 2 completely absorbs the sound. Each cylindrical thin tube composed of multiple windings of paper in which fibers are entangled to form a non-reflected wave
0 is to absorb sound efficiently. The feature of this sound absorption is that the plane wave traveling in each cylindrical thin tube 20 toward the lower part of the cylindrical housing 2 does not travel in the sound absorbing and damping material 13 made of raised fibers such as felt or glass wool, but on the surface. Can travel through each smooth cylindrical thin tube 20 without being subjected to the viscous resistance of air particles, so that a vibrant and highly vibrant sound can be reproduced.

In the above-described second embodiment, seven cylindrical thin tubes 20 are filled and housed in the cylindrical casing 2, but the number is not limited to seven, and a plurality of cylindrical thin tubes 20 may be stored. May be accommodated.

In the above second embodiment, the housing base portion 3, the external opening 4 and the bottom plate 7 used in the first embodiment are provided in the lower portion of the cylindrical housing 2. Is not limited to this, the entire lower surface of the cylindrical housing 2 is opened,
A supporting member such as a leg portion for supporting the cylindrical casing 2 so as to stand upright may be provided. In addition, the lower structure of the cylindrical housing 2 is shown in FIG.
The structure may be the same as that of the first modification of FIG.

In the second embodiment described above, the cylindrical thin tube 20 is used, but the present invention is not limited to this, and as shown in the following example, the present invention is not limited to a cylinder, but other shapes such as a polygon and an ellipse. The cross-section may have a tubular shape.

<Fourth Modification> FIG. 11 shows a cylindrical housing type speaker device according to a fourth modification, which corresponds to FIG.
It is a transverse cross-sectional view of the −D ′ plane. This fourth modification is shown in FIG.
Compared with the second embodiment of No. 0, in the internal space 20a of each cylindrical thin tube 20, a cylindrical thin tube 25 narrower than the cylindrical thin tube 20 is provided.
It is characterized by being filled with 5 and accommodated. This extends the maintenance function of the plane wave in each cylindrical thin tube to the high range,
Furthermore, the sound absorbing effect in the cylindrical housing 2 can be enhanced.
In addition, in the fourth modified example, 7 per 7
Although the cylindrical thin tubes 25 are filled and housed, the present invention is not limited to this, and preferably four cylindrical thin tubes 25 or a plurality of cylindrical thin tubes 25 may be housed.

<Fifth Modification> FIG. 12 shows a cylindrical housing type speaker device according to a fifth modification, which corresponds to FIG.
It is a transverse cross-sectional view of the −D ′ plane. The fifth modification is characterized in that a regular hexagonal tubular thin tube 26 is filled and housed in place of the cylindrical thin tube 20 according to the second embodiment.
In the case of this regular hexagonal tubular thin tube 26, the cross section becomes a so-called honeycomb shape, and there is no space between each regular hexagonal tubular thin tube 26, so that a large number of regular hexagonal tubular thin tubes 26 are accommodated to maintain the plane wave. The sound quality improvement can be remarkable.

<Sixth Modification> FIG. 13 shows a cylindrical housing type speaker device according to a sixth modification, which corresponds to FIG.
It is a transverse cross-sectional view of the −D ′ plane. The sixth modification is characterized in that an isosceles triangular tubular thin tube 27 is filled and housed in place of the cylindrical thin tube 20 according to the second embodiment. In the case of this isosceles triangular tubular thin tube 27,
Since there is no space between the isosceles triangular tubular thin tubes 27,
By accommodating a large number of isosceles triangular tubular thin tubes 27, it is possible to significantly improve the sound quality by maintaining the plane wave.

<Seventh Modification> FIG. 14 shows a cylindrical housing type speaker device according to a seventh modification, which corresponds to FIG.
It is a transverse cross-sectional view of the −D ′ plane. In the seventh modified example, instead of the cylindrical thin tube 20 according to the second embodiment, the cylindrical housing 2 is used.
The thin tube located in the central portion of is a cylindrical thin tube 20, and is characterized in that an elliptic tubular thin tube 28 is filled and housed between the cylindrical thin tube 20 in the central portion and the cylindrical housing 2. Since the inner diameter of each elliptic cylindrical thin tube 28 is not constant like a circle, a standing wave is unlikely to occur in the thin tube, and the elliptic cylindrical thin tubes 2 in the surroundings
Since the number of eight can be increased, the sound quality can be improved.

In the above embodiments and modifications, the cylindrical casing type speaker device has been described, but the shape of the cylindrical casing 2 is not limited to a cylinder, but may be a polygonal shape of a triangle or more or an elliptic cylindrical shape. May be.

[0088]

As described in detail above, according to the present invention, a cylindrical casing having a speaker unit at one end and an opening at the other end, and the cylindrical casing in a substantially vertical direction. In a cylindrical casing type speaker device or a structure thereof, which is provided so as to stand upright on the cylindrical casing, the opening of the cylindrical casing has a cross-sectional area smaller than the cross-sectional area of the cylinder bottom face of the cylindrical casing. A part of the other end of the cylindrical housing is closed and connected to an opening at the other end of the cylindrical housing to generate a plurality of sound waves radiated inside the cylindrical housing when the speaker unit is excited. The sound wave distributing means for distributing the sound waves into N sound waves and the propagation paths having substantially the same cross-sectional areas, respectively, and after propagating the distributed N sound waves through the respective propagation paths, A plurality of N radiations that radiate outward in a substantially horizontal direction through the external openings. And a cross-sectional area of the opening at the other end of the cylindrical housing, the distance from the opening at the other end of the cylindrical housing to the external opening of each of the propagation means via the sound wave distributing means. And the Helmholtz resonance frequency determined based on the volume of the cylindrical housing is set to substantially match the lowest resonance frequency of the speaker unit. Here, the area obtained by dividing the cross-sectional area of the opening at the other end of the cylindrical housing by the plurality N is preferably formed so as to substantially match the cross-sectional area of the propagation path of each of the propagation means. .

Therefore, according to the present invention, it is possible to reproduce a lower bass which cannot be obtained by the lower open type speaker device of the prior art, and the acoustic impedance at the lower open end of the cylindrical housing type speaker device is reduced. Prevents quantitative and qualitative deterioration of the reproduced sound in the low-pitched sound area caused by drastic changes,
From low tones around 30 to 40 Hz, which is fully satisfactory for practical use, 2
It is possible to reproduce a reproduced sound up to a high sound of about 0000 Hz without impairing the excellent characteristics of the cylindrical housing type speaker device. Furthermore, it is possible to provide a structure that eliminates the instability that is easily fallen, which is a weak point of the vertically-arranged cylindrical housing type speaker device.

According to another aspect of the invention, the cylindrical casing having the speaker unit at one end and the opening at the other end and the cylindrical casing are erected substantially vertically. In a cylindrical housing type speaker device or a structure thereof having a supporting means for supporting the cylindrical housing, the cylindrical housing is housed in the cylindrical housing such that a longitudinal direction of each cylindrical thin tube is substantially parallel to a longitudinal direction of the cylindrical housing. A plurality of cylindrical capillaries are provided for substantially maintaining the acoustic waves radiated inside the cylindrical casing as plane waves when the speaker unit is excited.

Therefore, according to the present invention, when the speaker unit is excited, the sound wave radiated inside the cylindrical casing can be substantially maintained as a plane wave, and a complicated waveform such as a musical sound can be further suppressed. Can be faithfully reproduced. Further, regardless of the cross-sectional diameter of the housing, it is possible to maintain the plane wave from the low sound to the high sound range without using a lot of sound absorbing and damping material.

[Brief description of drawings]

FIG. 1 is a perspective view showing a structure of a cylindrical housing type speaker device according to a first embodiment of the present invention.

FIG. 2 is a front view of the cylindrical housing type speaker device of FIG.

3 is a vertical cross-sectional view taken along the line B-B 'of FIG.

FIG. 4 is a cross-sectional view taken along the line A-A ′ of FIG.

FIG. 5 is a vertical cross-sectional view of a cylindrical housing type speaker device according to a first modification, corresponding to FIG. 3.

6 is a horizontal cross-sectional view of the cylindrical housing type speaker device of FIG. 5 taken along the line CC ′ of FIG. 4.

FIG. 7 is a horizontal cross-sectional view of a cylindrical casing type speaker device according to a second modification, taken along the line CC ′ of FIG. 4.

FIG. 8 is a transverse cross-sectional view of the cylindrical housing type speaker device according to the third modification, taken along the line CC ′ of FIG. 6;

FIG. 9 is a partially cutaway perspective view showing the structure of a cylindrical housing type speaker device according to a second embodiment of the present invention.

10 is a cross-sectional view taken along the line D-D 'of FIG.

11 is a transverse cross-sectional view of the cylindrical housing type speaker device according to the fourth modification, taken along the line DD ′ of FIG.

FIG. 12 is a transverse cross-sectional view of the cylindrical housing type speaker device according to the fifth modification, taken along the line DD ′ of FIG. 10.

FIG. 13 is a transverse cross-sectional view of the cylindrical housing type speaker device according to the sixth modification, taken along the line DD ′ of FIG. 10.

FIG. 14 is a transverse cross-sectional view of the cylindrical housing type speaker device according to the seventh modification, taken along the line DD ′ of FIG.

[Explanation of symbols]

1 ... speaker unit, 1a ... diaphragm, 1b ... Magnet, 2 ... Cylindrical housing, 3, 103 ... Casing base portion, 4, 104 ... External opening, 5 ... opening, 6, 106 ... Sound wave distribution member, 7,107 ... bottom plate, 10 ... Closure ring, 11, 111 ... Conducting tube, 12, 112 ... Sound wave reflection preventing member, 13,113 ... Sound absorbing and damping material, 20 ... Cylindrical thin tube, 20a ... internal space, 21, 22 ... space, 25 ... Cylindrical thin tube, 26 ... Regular hexagonal tubular thin tube, 27 ... Isosceles triangular tubular thin tube, 28 ... Elliptic cylindrical thin tube.

Claims (14)

[Claims] 1. A cylindrical casing having a speaker unit at one end and an opening at the other end, and a supporting means for supporting the cylindrical casing so as to stand in a substantially vertical direction. In a tubular housing type speaker device provided with, a part of the other end of the tubular housing is closed so that the opening of the tubular housing has a cross-sectional area smaller than the cross-sectional area of the bottom surface of the tubular housing. A sound wave distribution unit that is connected to the opening at the other end of the cylindrical housing and that distributes a sound wave radiated inside the cylindrical housing into a plurality of N sound waves when the speaker unit is excited, Has a propagation path of the same cross-sectional area, the plurality of distributed N sound waves are propagated through the respective propagation paths, and then, through the external openings, to the outside in a substantially horizontal direction. A plurality of N radiating means for radiating, and an opening at the other end of the cylindrical housing Of the Helmholtz determined based on the distance to the external opening of each of the propagating means through the sound wave distributing means, the cross-sectional area of the opening at the other end of the tubular housing, and the volume of the tubular housing. A cylindrical casing type speaker device, wherein a resonance frequency is set to substantially match the lowest resonance frequency of the speaker unit. 2. An area obtained by dividing the cross-sectional area of the opening at the other end of the cylindrical casing by the plurality N is formed so as to substantially match the cross-sectional area of the propagation path of each of the propagation means. The tubular casing type speaker device according to claim 1. 3. The cylindrical housing type speaker device according to claim 1, wherein the sound wave distributing means is provided with a sound wave reflection preventing member on a surface for distributing a sound wave. 4. The cylindrical casing is housed so that the longitudinal direction of each cylindrical thin tube is substantially parallel to the longitudinal direction of the cylindrical casing, and is housed inside the cylindrical casing when the speaker unit is excited. 4. The cylindrical casing type speaker device according to claim 1, further comprising a plurality of cylindrical capillaries for maintaining the emitted sound wave as a substantially plane wave. 5. A cylindrical casing having a speaker unit at one end and an opening at the other end, and a supporting means for supporting the cylindrical casing so as to stand in a substantially vertical direction. In a cylindrical housing type speaker device, the cylindrical housing is housed in the cylindrical housing such that the longitudinal direction of each cylindrical capillary is substantially parallel to the longitudinal direction of the cylindrical housing, and the cylindrical housing is excited when the speaker unit is excited. A cylindrical casing type speaker device comprising a plurality of cylindrical capillaries for substantially maintaining a sound wave radiated inside the body as a plane wave. 6. Each of the tubular capillaries is a cylindrical capillary, and the diameter of each of the tubular capillaries is shorter than the upper limit wavelength of the fundamental tone of the plane wave to be maintained, and the upper limit of the third harmonic of the plane wave to be maintained. The cylindrical casing type speaker device according to claim 4 or 5, wherein the speaker device is set to be longer than the wavelength. 7. The sound absorbing and damping material provided between each of the tubular capillaries and the cylindrical casing, further comprising: a sound absorbing and damping material. Cylinder housing type speaker device. 8. A tubular casing having a speaker unit at one end and an opening at the other end, and support means for supporting the tubular casing so as to stand upright in a substantially vertical direction. In the structure of the tubular housing type speaker device provided, a part of the other end of the tubular housing is closed so that the opening of the tubular housing has a cross-sectional area smaller than the cross-sectional area of the bottom surface of the tubular housing. Sound wave distribution means connected to the opening at the other end of the cylindrical housing and distributing sound waves radiated inside the cylindrical housing into a plurality of N sound waves when the speaker unit is excited; After having propagated the plurality of distributed N sound waves through the respective propagation paths, each of which has a propagation path of substantially the same cross-sectional area, and then through the respective external openings, in a substantially horizontal direction. A plurality of N propagating means for radiating to the outside are provided, and the other end of the cylindrical casing is opened. Section to the external opening of each of the propagation means through the sound wave distributing means, the cross-sectional area of the opening at the other end of the cylindrical housing, and the volume of the cylindrical housing. A structure of a cylindrical casing type speaker device, wherein a Helmholtz resonance frequency is set to substantially match a lowest resonance frequency of the speaker unit. 9. The area formed by dividing the cross-sectional area of the opening at the other end of the cylindrical housing by the plurality N is formed so as to substantially match the cross-sectional area of the propagation path of each of the propagation means. The structure of the cylindrical housing type speaker device according to claim 8. 10. The structure of the cylindrical housing type speaker device according to claim 8, wherein the sound wave distributing means is provided with a sound wave reflection preventing member on a surface for distributing a sound wave. 11. The cylindrical casing is housed so that the longitudinal direction of each cylindrical capillary is substantially parallel to the longitudinal direction of the cylindrical casing, and when the speaker unit is excited, it is housed inside the cylindrical casing. 11. The structure of the cylindrical housing type speaker device according to claim 8, further comprising a plurality of cylindrical capillaries for maintaining the emitted sound waves as substantially plane waves. . 12. A tubular casing having a speaker unit at one end and an opening at the other end, and support means for supporting the cylindrical casing so as to stand in a substantially vertical direction. In the structure of the cylindrical housing type speaker device provided, the cylindrical thin tubes are housed in the cylindrical housing so that the longitudinal direction thereof is substantially parallel to the longitudinal direction of the cylindrical housing, and when the speaker unit is excited, A structure of a cylindrical housing type speaker device, comprising a plurality of cylindrical thin tubes for substantially maintaining a sound wave radiated inside the cylindrical housing as a plane wave. 13. Each of the tubular capillaries is a cylindrical capillary, and the diameter of each of the tubular capillaries is shorter than the upper limit wavelength of the fundamental tone of the plane wave to be maintained, and 3 mm of the plane wave to be maintained.
13. The structure of the cylindrical housing type speaker device according to claim 11 or 12, wherein the structure is set to be longer than the upper limit wavelength of the overtone. 14. The sound absorbing and damping material provided between each of the tubular capillaries and the cylindrical housing, further comprising: a sound absorbing and damping material as set forth in any one of claims 8 to 13. Structure of a cylindrical housing type speaker device.