KR20000047010A - Speaker system - Google Patents

Abstract

PURPOSE: A speaker system is provided to promote efficiency and clearly transfer base sound. CONSTITUTION: A speaker system comprises:a first isolation member isolating the vicinity of one end of a sound impedance matching means; and a second isolation member isolating the vicinity of other end of the sound impedance matching means. An enclosure (30,60,152) is formed between the first isolation member and the second isolation member. The enclosure accommodates gas heavier than air ,that is the gas is slower than air so the speaker system can generates base and minimize size of a sound resonance tube as well. In particular, the speaker system generating base sound can use smaller size of a hone or a sound mirror.

Description

Speaker system

The present invention relates to a device for transmitting, guiding, or directing sound of an acoustic device, and more particularly, a device that can reduce the size while delivering high efficiency and low sound by forming a sealed space and filling a gas that is heavier than air. It is about.

The biggest problem with conventional general speaker systems is low efficiency. In addition, large enclosures were required to reproduce low frequency bass. The Horn Speaker System was developed to solve this problem. By matching the diaphragm of the speaker unit with the impedance of the air, the system can be several times more efficient than a conventional speaker system. As a result, it can be driven by a much smaller output amplifier.

By the way, the horn speaker system has been put into practical use for the mid-range and high-pitched sounds, but only a part of the low pitch is used. The reason is the huge size. If a horn is to be reproduced up to 20 Hz, the lowest frequency that humans can hear, the following conditions must be met:

Where Sm = area of the horn, λ = wavelength = (sonic / frequency).

If the cross section of the horn is circular and the radius is r, then the radius is calculated as

2 π r> λ

The wavelength of a sound at 20 Hz is 340/20 = 17 m, which is the air velocity 340 m / s divided by the frequency 20. Substituting this in the above equation requires a horn with a large circular opening approximately 5.4 m in diameter.

As such, a tube used in a speaker system or musical instrument to transmit, guide, or direct sound becomes large in bass.

Accordingly, it is an object of the present invention to provide a device that delivers, directs, or directs small sound while delivering high efficiency and good bass. Further, such a device is applied to a speaker system.

1 is a cross-sectional view of a horn speaker system according to an embodiment of the present invention.

2 is a cross-sectional view of a transmission line speaker system in accordance with an embodiment of the present invention.

3 is a cross-sectional view of a transmission line speaker system according to another embodiment of the present invention.

4 is a cross-sectional view of a pipe organ according to an embodiment of the present invention.

* Explanation of symbols for the main parts of the drawings

10,50,100: Speaker system 12: Horn

14,52,102: Speaker Unit 16: Neck

18: openings 24,55,154: first membrane

26,56,156: Second membrane 30,60,152: Enclosed space

54,104,150: acoustic resonator (resonance tube) 106,110: diaphragm

108: transducer 112: support

According to the present invention, the both ends of the device for transmitting, directing, or directing a sound made of a pipe are blocked and sealed, and a gas that is heavier than air is accommodated in the sealed space. In gases heavier than air, the speed of sound decreases, reducing the tube size.

According to an aspect of the present invention, in a speaker system having a speaker unit and an acoustic impedance matcher to which the speaker unit is attached at one end thereof,

And a first blocking member for blocking the vicinity of one end in the longitudinal direction of the acoustic impedance matcher, and a second blocking member for blocking the vicinity of the other end in the longitudinal direction of the acoustic impedance matcher. A space enclosed by the second blocking member is formed,

The enclosed space is provided with a speaker system, characterized in that gas that is heavier than air is accommodated.

According to another aspect of the invention, in the acoustic resonator tube used in a speaker system or musical instrument,

The first blocking member and the second blocking member provided near the one end in the longitudinal direction to block the end, and the second blocking member disposed near the other end in the longitudinal direction to block the other end. A space enclosed by the second blocking member is formed,

The sealed space is provided with an acoustic resonator tube, characterized in that a gas that is heavier than air is accommodated.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. Referring to Figure 1, the horn speaker system 10 has a horn 12 and a speaker unit (also called a driver) 14. Horn 12 has throat 16 and mouth 18. The wall 19 of the horn 12 having a circular cross section extends from the neck 16 to the opening 18, where the wall 19 flared outwards from the neck 16 to the opening 18. )All. The cross-sectional area of the horn 12 increases in proportion to some constant function. This ratio is an exponential horn according to the exponential function.

The speaker unit 14 is attached to the neck 16 of the horn 12. The speaker unit 14 includes a diaphragm and a transducer for generating sound. The transducer converts an electrical signal into mechanical movement. The transducer may be a voice coil system or a piezoelectric body. The neck 16 of the horn 12 is preferably the same size as the neck of the speaker unit 14, but may be smaller.

To the neck 16 of the horn 12 a first membrane 24 is attached to block the neck substantially perpendicular to the longitudinal direction of the horn. A second membrane 26 is also attached to the opening 18 to block the opening. The first and second membranes consist of a film of rubber or silicone rubber. An enclosed space 30 is formed which is isolated from the outside air by the first membrane 24, the second membrane 26 and the wall 19 of the horn.

In the sealed space 30, a heavier gas than air is accommodated. The larger the molecular weight of the gas to be contained, the better. However, it is preferable that the gas to be contained does not act chemically and is harmless to the human body. For example, xenon (Xe) gas may be used.

Heavy gases are intended to reduce the size of the horn to make it practical. In order to reduce the size of the horn, it is best to shorten the wavelength. That is, it can be seen from the following equation that it is necessary to reduce the speed of sound inside the horn 12.

Where Sm = area of the horn opening 18, lambda = wavelength, C = sound velocity, and f = frequency. On the other hand, the speed of sound is inversely proportional to the square root of the molecular weight.

Assuming that the enclosed space 30 is filled with xenon having a molecular weight of 131, the speed of sound therein is about 160 m / s (here, the speed of sound in air is assumed to be 340 m / s and the molecular weight of air is 29). ). Substituting this in Equation 3 and assuming that the opening is circular, it can be seen that the diameter of the opening 18 of the horn 12 is reduced by about 0.46 times the opening of the horn made of air.

On the other hand, the flare constant m can be obtained by the following equation.

In the case of general air, when the low cutoff frequency is set at the practical limit of 60 Hz, the m value is

m _air = 4 π 60/340 = 2.22

Becomes In a gas such as Xe with a high molecular weight, the sound velocity is about 160 m / s,

m _Xe = 4 π _60/160 = 4.7

Becomes

Substitute the values of m into Eq. 3 to compare the size of the horn openings. In the case of air,

Sm _air = 340² / 4 π 60² = 2. 56 m²

Xe having a molecular weight of 131

Sm _Xe = 160² / 4 π 60² = 0.57 m²

As a result, it can be seen that the size is reduced to about 2/9 as in the case of air.

Now compare the lengths. The length of the horn is the

Sm = St × e ^mx

(Sm = area of the horn opening, St = area of the horn, m = flare constant, x = length of the horn), so the length x is

Becomes If St is 0.049 m, the length of the horn in air

x _air = 1 / 2.22 [ln (2.56 / 0.049)] = 1.78 m

For aircraft Xe with a sound velocity of 160 m / s,

x _Xe = 1 / 4.7 [ln (0.57 / 0.049)] = 0.52 m

It can be seen that the length is also shortened to about 1 / 3.4 of the horn length in air. Thus, both the size and length of the horn are significantly reduced, allowing a low-end horn of practical size.

In the above embodiment, the horn having a circular cross section has been described, but the cross sectional shape of the horn is not limited thereto. It may be square or rectangular polygon, or elliptical. In the above embodiment, the flare ratio of the horn is an exponential function. Alternatively, the horn flare ratio may be a hyperbolic, conical or parabolic function.

This attempt to use a slow sound gas is equally applicable to the horn speaker system as well as to the transmission line (or quarter wave loading) speaker system 50 as shown in FIG. The transmission line speaker system 50 includes a speaker unit 52 and an acoustic resonator (resonance tube) 54 made of a cylindrical tube having a constant cross-sectional area. The speaker unit 52 is composed of a diaphragm and a transducer. The first resonator 55 is attached to the acoustic resonance tube 54 adjacent to the speaker unit 52. (In other embodiments, the first membrane may be omitted and the diaphragm may act as a blocking member.) The second membrane 56 is also attached to the opposite opening. The first and second membranes consist of a film of rubber or silicone rubber. The enclosed space 60 is formed by the first membrane 55, the second membrane 56 and the wall 58 of the acoustic resonator tube 54 to be isolated from the outside air.

In the sealed space 60, a heavier gas than air is accommodated. The larger the molecular weight of the gas to be contained, the better. However, it is preferable that the gas to be contained does not act chemically and is harmless to the human body. For example, xenon (Xe) gas may be used.

This speaker system uses the principle of causing resonance when the length of the acoustic resonance tube 54 is one quarter of the wavelength of a specific frequency. Wavelength is the speed of sound divided by frequency,

(Here, λ: wavelength, C: sound velocity, F: frequency)

If you make a transmission line that reproduces up to 60 Hz, the wavelength

λ = 340/60 = 5.67 m

Therefore, the length L of the acoustic resonance tube 54 should be 1.42 m, which is one quarter of the wavelength. If the enclosed space is filled with Xe, the sound velocity is 160 m / s and the length of the acoustic resonance tube 54 is 2.67 m. That is, 0.67 times the length corresponding to that of air, which is also considerably shorter.

3 shows another embodiment. Referring to FIG. 3, the transmission line speaker system 100 according to another embodiment also includes a speaker unit 102 and an acoustic resonator 104 made of a cylindrical tube having a constant cross-sectional area. The speaker unit 102 is composed of a diaphragm 106 and a transducer 108. One side of the acoustic resonance tube 104 is blocked by the diaphragm 106. The other side is attached to the diaphragm 110 which functions as a passive radiator (without a transducer). No transducer is attached to the diaphragm 108. Between the outer periphery of the diaphragm 106 and 110 and the acoustic resonator tube 104, a support 112 of flexible material is interposed to attach the diaphragm 110 to the acoustic resonator tube 104.

The enclosed space 114 is isolated from the outside air by the diaphragms 106 and 110 and the wall 105 of the acoustic resonance tube 104. In the sealed space 114, a gas that is heavier than air is accommodated. The larger the molecular weight of the gas to be accommodated, the better, but it is preferable that the gas is not chemically active with the materials of the diaphragms 106 and 110 and the support 112, and is harmless to the human body. For example, xenon (Xe) gas can be used.

4 shows the concept of the present invention applied to an acoustic resonance tube of an instrument (pipe organ). The first membrane 154 and the second membrane 156 are attached to form a closed space 152 on both sides of the acoustic resonance tube 150. In the sealed space 152, a heavier gas than air is accommodated.

The speaker system according to the present invention can reproduce the bass while reducing the size of the horn or the acoustic resonance tube. In particular, a speaker system that reproduces bass can be used with a reduced horn or acoustic maze. In the case of musical instruments, the size of the resonator tube can be reduced.

Claims (4)

A speaker system having a speaker unit and an acoustic impedance matcher to which the speaker unit is attached at one end thereof, The first blocking member and the second blocking member for blocking near the other end of the acoustic impedance matcher, and the second blocking member for blocking near the other end of the acoustic impedance matcher, the first blocking member and the first 2 a closed space is formed by the blocking member, Speaker system, characterized in that the gas heavier than air is accommodated in the sealed space. According to claim 1, wherein the impedance matcher is made of a horn having a neck and an opening opening to which the speaker unit is attached, the first blocking member installed in the neck is made of a diaphragm of the speaker unit, is installed in the opening The second blocking member is a horn speaker system, characterized in that consisting of passive diaphragm. In an acoustic resonator tube used in a speaker system or an instrument, The first blocking member and the second blocking member provided near the one end in the longitudinal direction to block the end, and the second blocking member disposed near the other end in the longitudinal direction to block the other end. A space enclosed by the second blocking member is formed, Acoustic resonator tube, characterized in that the gas heavier than air is accommodated in the sealed space. The acoustic resonator tube of claim 3, wherein a speaker unit is installed at one end, the first blocking member is formed of a diaphragm of the speaker unit, and the second blocking member is formed of a passive diaphragm.