WO2007123307A1

WO2007123307A1 - Apparatus for filtering of sound

Info

Publication number: WO2007123307A1
Application number: PCT/KR2007/001405
Authority: WO
Inventors: Wan Jin Chung
Original assignee: Spk Alliance Ltd.
Priority date: 2006-04-21
Filing date: 2007-03-22
Publication date: 2007-11-01

Abstract

The present invention relates to an apparatus for filtering sound, in which a filter panel is suspended by elastic members and filters sound waves from a sound source to correct distorted wave forms by making compressions and rarefactions of the sound waves uniform using the elastic force due to compression and expansion of the elastic members while the sound waves hit the filter panel. According to the invention, the audience can hear soft clear sound close to the original sound while listening a music or seeing a performance, even in a room equipped with a variety of structures that distort sound. Therefore, the invention is particularly useful for specialized-performance buildings having performance halls or theaters.

Description

APPARATUS FOR FILTERING OF SOUND

Technical Field

[1] The present invention relates to an apparatus for filtering sound, particularly, to an apparatus for filtering sound that provides natural and clear quality of sound to the audience by removing distortions in sound waves and filtering the sound waves to have curves having smooth wave forms. Background Art

[2] Recently, people enjoy a variety of cultural activities due to an increase in the standard of living. Further, as cultural activities become popular, architectural sound design is considered.

[3] The architectural sound design is classified into noise control design for preventing harm to the environment due to sound transmitted from a performance hall or home and interior sound design controlling the quality of sound practically heard by the audience in a room.

[4] As for the noise control design, to block sound transmitted into a room from the outside and to the outside from a room, generally sound-absorbing panels are constructed in the wall, ceiling, and floor.

[5] On the other hand, in the interior sound design for providing the audience with the highest quality of sound through the interior structure that is generated from practical sound sources, including electric sound from electric sound equipment, such as an amplifier, an equalizer, an electric instrument, and a speaker, and an acoustic sound from acoustic instruments, the shapes of the sound equipment and the inside, a finish material, and the attachment structure of the finish materials should be compositively considered in terms of the usage of a performance hall and the location of the audience. Disclosure of Invention Technical Problem

[6] Sound-absorbing panels have advantages of maintaining a pleasant environment by blocking sound transmitted into a room from the outside and to the outside from a room as well as controlling sound, such as reverberation, resonance, and echo. However, portions of the wave forms of the sound becomes irregularly distorted while being absorbed into the sound-absorbing panels due to irregular amounts of sound being absorbed according to the frequencies and the sound-absorbing levels, such that it affects the sound that is heard by audience. Consequently, the quality of sound is reduced because of the noise.

[7] Further, it is possible to equip a room with expensive sound equipment or modify the shape and structure of the room in order to improve the quality of sound transmitted to the audience in a room in the interior sound design. However, it increased the equipment costs and removing distorted noise in sound generated from sound sources even though the room is equipped with the best sound equipment along with modified inner structure was limited. Further, because the sound waves were uneven due to contact made with other structures in the room, it had a technical limitation in improving the quality of sound that the audience could practically detect.

[8] A sound travels as a sound wave that is generated by compression and expansion of air and distorted portions appear in wave form when the density of the air is nonuniform in the compression and expansion. Therefore, audience hear unnatural and disturbed noise due to the distorted portions.

[9] Noise, though at the same sound pressure level, is felt stronger by the audience when it travels through non-uniform compression and expansion in the density of air rather than uniform compression and expansion.

[10] Distortion of sound particularly badly affects the work condition of musicians, speakers, and sound engineers in a performance hall.

[11] For example, when hearing a sound made by himself/herself, a musician hears partially distorted sound due to the surroundings in a room, such that the musician is disturbed in playing because he/she cannot feel the original sound made from the instrument due to the distorted portions. Therefore, the distortion makes the sound generated in playing more unstable.

[12] In order to overcome the above problems in the related art, it is an object of the invention to provide an apparatus for filtering sound that allows audience to hear soft, clear sound, not a thick sound by making sound traveling through non-uniform compression and expansion in density of air travel through uniform compression and expansion.

[13] It is another object of the invention to provide an apparatus for filtering sound that reduces intensity of noise heard by the audience, without specific sound-absorbing, by removing as much as possible harsh portions transmitted to the audience of noise in a wide range of tones, i.e. having very irregular compressions and rarefactions. Technical Solution

[14] In order to accomplish the objects, an apparatus for filtering sound of the invention includes an upper supporting portion, upper elastic members that each have elasticity and an end fixed to the upper supporting portion, and a filter panel of which the upper portion is fixed to the upper elastic members.

[15] Further, the apparatus for filtering sound of the invention further includes lower elastic members mounted on the lower end of the filter panel and a lower supporting portion where ends of the lower elastic members are fixed.

Advantageous Effects

[16] According to the invention, since filter panels are suspended by elastic members, when sound waves generated from sound resources hit the filter panels, compressions and rarefactions in the sound waves are made uniform through filtering by the elastic force due to compression and expansion of the elastic members, so that distorted wave forms are corrected. Further, it is possible to considerably reduce the magnitude of noise that is practically felt by the audience by changing wave forms of sound soft without reducing the volume of the sound using sound absorption.

[17] By using the invention, the audience can hear soft, clear sound close to the original sound even if they watch a concert or other performances in a room equipped with structures that may distort sound. Therefore, the invention is particularly useful for specialized-performance buildings having performance halls or theaters. Brief Description of the Drawings

[18] FIGS. 1 and 2 are schematic views of an apparatus for filtering sound according to a preferred embodiment of the invention.

[19] FIG. 3 shows a sine wave graph illustrating the principle of the invention.

[20] FIG. 4 shows a graph of frequency response characteristics to sound pressures comparing sound waves measured in an empty room and a room equipped with an apparatus for filtering sound of the invention.

[21] FIG. 5 is a schematic view of the apparatus for filtering sound of the invention used in the experiment in relation to FIG. 4 provided in a room.

[22] FIGS. 6 to 12 are schematic views of other embodiments of the invention.

[23] FIGS. 13 to 17 are a variety of modifications for a filter panel of the invention.

Mode for the Invention

[24] Preferred embodiments of the invention are described hereafter in detail with reference to the accompanying drawings.

[25] Installed where sound is generated from sound sources, an apparatus for filtering sound according to a first embodiment of the invention, as shown in FIGS. 1 and 2, includes a filter panel 20 suspended by upper elastic members 10 at a predetermined distance from the walls 3 in a room 1.

[26] The filter panel 20 has a thick plate shape with two flat sides and may be formed of any materials, such as a wooden plate, aluminum plate, steel plate, synthetic resin plate, etc. However, a metal plate and a wood plate are preferable because they provide more uniform and effective expansion and compression, i.e. compressions and rarefactions.

[27] The filter panel 20 is suspended at a predetermined elevation from the floor by elastic support of the upper elastic members 10 of which ends are connected to the upper end. [28] Although a coil spring is exemplified for the upper elastic member 10 in the invention, a leaf spring other than the coil spring, or other elastic bodies than a spring may be used. [29] The other ends of the upper elastic members 10 are fixed to an upper supporting part 30. A specific member may be used as an upper supporting part 30, but when the apparatus for filtering sound is installed in a room 1, as shown in FIGS. 1 and 2, the ceiling of the room 1 may be the upper supporting part 30. [30] The upper supporting part 30 includes fixing rings 31 to fix the other ends of the upper elastic members 10. [31] According to the invention having the above configuration, when sound waves generated out of a sound source hit the filter panel 20 elastically suspended through the upper elastic members 10, a part of the sound waves is reflected and the other is diffracted and transmitted to the rear side of the filter panel 20. [32] The filter panel 20 generates fine movements by the wave energy of the sound and the upper elastic members 10 extend and compress due to the fine movements. [33] The upper elastic member 10 convert the non-uniform sound waves into smooth waves and reflects them as shown in FIG. 2 by restraining non-uniform compressions and rarefactions in the air hitting the filter panel 20 in the opposite direction through the compression and extension.

[34] This principle is explained in brief as follows.

[35] A sound or sound wave is disturbance on density of gas in the same way as pressure of which disturbance is generated in the gas by periodic changes in air pressure due to vibration of a sound source. [36] A sound wave in a gas is a longitudinal wave resulting from continuous compression and expansion transmitted through the gas, as an elastic wave or dense wave. [37] The sound wave, of a pure tone, as shown in FIG. 3, appears as a wave form that continuously undulates up and down in uniform level of sound pressure within a predetermined interval, uniformly compressing and expanding air at a constant frequency. [38] Most sounds, however, are very complicated complex tones, not of pure tone, and of which level of sound pressure changes irregularly according to the frequency. [39] When the density of air, which is compressed and expanded in transmission of a sound wave, is non-uniform, the non-uniform density non-uniformly distorts a part of the sound wave forming a wave form and causes an abnormal sound. Consequently, the distorted sound is heard by the audience as a sound reduced in quality. [40] The graph shown in FIG. 4 was given to compare a sound wave 100 in an empty room without an apparatus for filtering sound of the invention with a sound wave 200 in a room installed with the apparatus for filtering sound of the invention. The apparatus for filtering sound of the invention was installed as shown in FIG. 5 in which several filter panels 20 are disposed around the walls.

[41] The graph indicates experimental values measured by a common sound wave detector that is able to measure sound wave levels to frequency of vibration. The filter panels 20 used in this experiment of the invention was formed of a steel plate of 0.8 mm thickness and 120x120 cm area.

[42] As seen from FIG. 4, as for the sound wave 100 measured in an empty room, distorted wave forms that roughly vibrate appeared at the peaks and troughs.

[43] The wave form of an interior sound is easy to be distorted by a variety of interfering or disturbing factors in the room and heard by the audience as small noise. Accordingly, it prevents the audience from hearing the original sound from the sound source and deteriorates the quality of the sound. The distortion of the sound wave results from non-uniformity in the density of air that results during the compression and expansion of air.

[44] On the other hand, as for the sound wave 200 measured in a room equipped with the apparatus for filtering sound of the invention, it appeared as a smooth curve wave form that did not have the distorted wave forms.

[45] The reason is that when the sound wave from the sound source hits the filter panel

20, the upper elastic members 10 compress and extend according to the wave energy of the sound wave, non-uniform compressions and rarefactions are restrained in the opposite direction in the air hitting the filter panel 20 by the compression and extension such that energy density of sound becomes uniform and the wave form of sound changes into soft wave form.

[46] To be more detailed, because sound energy for the non-uniform compressions in the sound wave is restrained by repulsion due to the elastic force of the upper elastic members 10, the rough non-uniform wave forms at the compressions are smoothed, while because sound energy for the non-uniform rarefactions in the sound wave is restrained by attraction due to the elastic force of the upper elastic member 10, the rough non-uniform wave forms at the rarefactions are smoothed.

[47] As seen from the graph, the sound heard in the room equipped with the apparatus for filtering sound of the invention provides considerably clear quality of sound as compared with the empty room.

[48] On the other hand, according to a second embodiment of the invention, as shown in

FIG. 6, a plurality of filter members 20 may be arranged one after the other at a predetermined interval from the wall 3.

[49] This configuration is made to achieve better soft, clear quality of sound by filtering the sound several times with the filter panels 20.

[50] On the other hand, an apparatus for filtering sound according to a third embodiment of the invention, as shown in FIG. 7, includes lower elastic members 40 mounted on the lower end of a filter panel 20 and a lower supporting part 41 where ends of the lower elastic members 40 are fixed.

[51] The lower supporting part 41, for example as shown in FIG. 7, may be the floor of a room or a support frame additionally provided on the floor.

[52] Further, the third embodiment of the invention includes fixing rings 42 to fix the other ends of the lower elastic members 40.

[53] The apparatus for filtering sound according to the third embodiment of the invention is more effective with increase in size of the filter panel 20.

[54] As the filter panel 20 increases in size, the elastic force of the upper elastic members 10 may not be sufficiently transmitted to the lower portion, thereby reducing the filtering effect of the sound at the lower portion of the filter panel 20.

[55] Accordingly, the third embodiment of the invention was designed such that filtering effect at the lower portion of the filtering panel 20 is not reduced even for the large- sized filter panel 20 by elastically fixing the lower end of the filter panel 20 and uniform filtering effect is achieved throughout the filtering panel 20.

[56] An apparatus for filtering sound according to a fourth embodiment of the invention, as shown in FIGS. 8 and 9, may include a casing that contains a filter panel 20.

[57] As shown in FIG. 8, as the casing, a closed casing 50 having a closed space to receive the filter panel 20 may be used, or as shown in FIG. 9, an open casing 60 with a side open may be used.

[58] According to the fourth embodiment of the invention, the upper side of each of the casings 50, 60 serves as an upper supporting part 30 that supports the upper end of the filter panel 20 and the lower side of each of the casings 50, 60 serves as a lower supporting part 41 that supports the lower end of the filter panel 20. Further, wheels 70 may be provided below the casings 50, 60 to facilitate movement.

[59] An apparatus for filtering sound according to a fifth embodiment of the invention, as shown in FIG. 10, may include a frame member consisting of a base frame 81 forming the lower end, side frames 82 vertically disposed at both sides of the base frame 81, and an upper frame 83 connected with the side frames and where upper elastic members 10 are mounted, and wheels 70 mounted below the base frame 81.

[60] The upper frame 83 serves as an upper supporting part that supports the upper end of the filter panel 20 and the base frame 81 a lower supporting part that supports the lower end of the filter panel 20.

[61] This configuration is designed to easily move and freely install and remove the apparatus for filtering sound, if needed. [62] According to the fifth embodiment of the invention, the apparatus for filtering sound may be constructed together with the walls or the ceiling of a building in order not to be exposed to the outside. FIGS. 11 and 12 show embodiments in which the apparatus for filtering sound was constructed in the wall and the ceiling, respectively, according to the fifth embodiment of the invention.

[63] In general, a wall finish material 3a is constructed on the interior walls, in the fifth embodiment of the invention, as shown in FIG. 11, the filter panel 20 is suspended in the empty space between the wall 3 and the wall finish material 3a by the upper elastic members 10.

[64] Further, a ceiling finish panel 2b is usually constructed under the slab 2a of the ceiling 2 of a building, in the fifth embodiment of the invention, a plurality of filter panels 30 is suspended at a predetermined interval in the empty space between the slab 2a and the ceiling finish panel 2b by the upper elastic members 10.

[65] When an apparatus for filtering sound is mounted in the walls and ceiling of a building according to the fifth embodiment of the invention, because sound waves transmitted to the ceiling as well as the walls are filtered, the quality of sound is substantially improved.

[66] According to the fifth embodiment of the invention, an apparatus for filtering sound can be constructed together with the building. Further, when the apparatus for filtering sound is constructed in a specialized-performance building, such as performance halls and theaters, it is not exposed to the outside and allow the gracefull beauty of the interior appearance.

[67] A variety of modifications for the filter panel 20 that is flexible in design depending on the structure of acoustic equipment and a room or the location of the audience are shown in FIGS. 13 to 17.

[68] As shown in FIG. 13, several through-holes 21 may be formed in the front side of a filter panel 20.

[69] The through-holes 21 are formed to filter a portion of sound waves traveling to the filter panel 20, transmitting the others. This configuration allows the filtering panel 20 to adjust the filtering amount of sound waves according to the degree of distortion of the sound waves from sound sources in a room. Therefore, it has an advantage of high flexibility in interior acoustic design.

[70] As shown in FIG. 14, a filter panel 20 may be formed in a C-shape in transverse cross-section.

[71] According to the shape, the filter panel 20 has a convex side, so that it is possible to achieve sound effects that diffuses sound waves and adjust the filtering amount of the sound waves according to the directions of the sound waves from sound sources.

[72] As shown in FIG. 15, a filter panel 20 may have alternate peaks and troughs, i.e. be formed in a chopping wave shape, in the transverse cross-section.

[73] Further, as shown in FIG. 16, a filter panel 20 may have alternate prominences and depressions, i.e. be formed in a pulse wave shape, in the transverse cross-section. Alternatively, as shown in FIG. 17, a filter panel 20 may be formed in a pulse wave with alternative prominences 22 and depressions 23 that are different in width in the transverse cross-section.

[74] As shown in FIGS. 16 and 17, when the filter panel 20 has prominences and depressions, it is possible to achieve unconventional sound effects by changing the degree of diffusion of sound waves.

Claims

[I] An apparatus for filtering sound, comprising: an upper supporting portion: upper elastic members that each have elasticity and an end fixed to the upper supporting portion; and a filter panel of which the upper portion is fixed to the other end of the upper elastic members. [2] The apparatus according to claim 1, wherein the plurality of filter panels are arranged one after the other at a predetermined interval. [3] The apparatus according to claim 1, further comprising: lower elastic members mounted on the lower end of the filter panel: and a lower supporting portion where ends of the lower elastic members are fixed. [4] The apparatus according to claim 1, further comprising: a casing that receives the components. [5] The apparatus according to claim 4, further comprising: wheels provided below the casing. [6] The apparatus according to claim 1, further comprising: a rectangular frame member that receives the components. [7] The apparatus according to claim 6, further comprising: wheels mounted on the frame member. [8] The apparatus according to claim 1, wherein a plurality of through-holes are formed in the filter panel. [9] The apparatus according to claim 1, wherein the filter panel is formed in a flat panel shape. [10] The apparatus according to claim 1, wherein the filter panel has a C-shaped transverse cross-section.

[I I] The apparatus according to claim 1, wherein the filter panel has alternate peaks and troughs in transverse cross-section.

[12] The apparatus according to claim 1, wherein the filter panel has alternate prominences and depressions in transverse cross-section.