JP2013222191A - Sound adjustment device and sound adjustment unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sound adjustment device and a sound adjustment unit which are capable of easily performing room tuning in various sound environments by equipment which has a simple structure and is light-weight and inexpensive.SOLUTION: A sound-absorbent diffusing panel 1 in which a plurality of sound-absorbent diffusers 6 obtained by forming a paper-made foldable core material 4 into an expanded cylindrical shape are juxtaposed within a square frame 7 is prepared, and a plurality of kinds of sound-absorbent reflecting panels 2 in each of which a plurality of sound-absorbent reflecting plates 13 different in ratio of sound absorbency and reflectance are fitted within a square frame 10 are prepared, and sound-absorbent diffusing panels 1 and sound-absorbent reflecting panels 2 selected from the plurality of kinds of sound-absorbent reflecting plates 2 are freely removably laminated, and a sound adjustment unit 3 obtained by laminating them is used, and the sound adjustment unit 3 is juxtaposed with one kind or other kinds of sound adjustment units in combination.

Description

  The present invention relates to an acoustic adjustment device and an acoustic adjustment unit suitable for room tuning in a music studio, a concert hall, an audio listening room, etc., and more specifically, an acoustic adjustment device of a type in which a plurality of types of block acoustic adjustment units are arranged side by side. The present invention relates to an acoustic adjustment unit applied to an acoustic adjustment device.

  Conventionally, many acoustic tuning devices and acoustic tuning units for room tuning have been implemented, but a sound absorbing panel is often installed on the wall surface or ceiling. In addition, as in Japanese Utility Model Laid-Open No. 2-69398 (Patent Document 1) and Japanese Patent No. 4739785 (Patent Document 2), a cylindrical sound absorber is arranged near the wall surface, and further, Japanese Patent No. 4112958. There is also a structure in which a sound-absorbing panel and a cylindrical sound-absorbing body are provided side by side as in Japanese Patent Publication (Patent Document 3).

  Japanese Utility Model Publication 2-69398   Japanese Patent No. 4739785   Japanese Patent No. 4112958

  Patent Document 1 describes a structure in which a plurality of acoustic adjustment cylinders filled with a sound absorbing auxiliary material made of paper honeycomb are arranged inside a cylindrical thin plate sound absorbing material. The structure is complicated and the sound absorbing effect of the paper honeycomb is reduced.

  Patent Document 2 describes a structure in which sound-absorbing bodies in which a porous skin material made of a lightweight metal such as aluminum is formed into a sawtooth uneven cylinder are arranged in a staggered manner in FIGS. 11 and 18 and in the description thereof. Yes. The porous skin material is made of a lightweight metal, and the configuration is extremely complicated because of the configuration in which a soft fiber sound-absorbing material and a central material with a protruding portion inside are provided inside the porous skin material. There is a disadvantage that it is expensive in weight.

  In Patent Document 3, a sound absorbing member in which a porous plate formed by laminating a mesh metal plate and a sound absorbing layer is formed in a cylindrical shape is sandwiched between a sound absorbing plate and a sound reflecting plate in a parallel state. A sound-absorbing panel having the above structure is described. The sound absorbing member has a complicated structure using a special metal layer and is relatively heavy and expensive.

  Accordingly, an object of the present invention is to provide a lightweight and inexpensive acoustic adjustment device and acoustic adjustment unit based on a simple structure without using a metal material. An object of the present invention is to provide an acoustic adjustment device and an acoustic adjustment unit that can easily perform room tuning of an acoustic environment.

  In order to achieve the above object, the invention of claim 1 is characterized in that a sound-absorbing diffuser in which a paper folding core material such as a paper bias core or a paper honeycomb core is formed into a stretched cylindrical shape is appropriately disposed in a rectangular frame. While preparing a plurality of sound-absorbing diffuser panels arranged in parallel in a substantially parallel state, a plurality of types of sound-absorbing reflector panels each having a sound-absorbing reflector plate with different ratios of sound-absorbing and reflecting properties fitted in a rectangular frame The sound absorption diffused panel and the sound absorbing reflective panel selected from a plurality of kinds are prepared and detachably superposed under the condition that the sound absorbing reflective panel is located on the back of the sound absorbing diffuser panel. An acoustic adjustment device using an adjustment unit and arranging a single species side by side or a combination of a plurality of types.

  The invention according to claim 2 is characterized in that the sound absorbing diffusion panel is detachably polymerized in a sandwich state located before and after the sound absorbing reflection panel, and a single type is arranged in parallel by using the acoustic adjustment unit obtained by the polymerization. The acoustic adjustment device according to claim 1, wherein a plurality of types are combined and arranged in parallel.

  The invention according to claim 3 is characterized in that an acoustic adjustment unit in which a double-adsorbed sound-absorbing diffusion panel is polymerized on the front surface of the sound-absorbing reflection panel is used, and a single type is arranged side by side or a plurality of types are arranged side by side. The acoustic adjustment device according to claim 1 or 2.

  According to a fourth aspect of the present invention, there is provided a sound-absorbing diffuser in which a sound-absorbing reflecting panel having a sound-absorbing reflecting plate fitted in a rectangular frame and a paper folding core material such as a paper bias core or a paper honeycomb core are formed into a stretched cylindrical shape. Is a sound adjustment unit in which a plurality of sound absorption diffusion panels arranged in parallel in a substantially parallel state are kept in a square frame in a detachable manner.

  The invention according to claim 5 is the acoustic adjustment unit according to claim 4 to which a sound-absorbing diffuser in which a foldable core material using corrugated cardboard as a raw paper material is wound around a shaft core is applied.

  The invention of claim 6 adopts any one of hard magnesium plate, foamed magnesium plate, wood plate, rock wool plate or a laminate of two or more thereof as the sound absorbing reflector in the sound absorbing reflector panel. Item 6. The acoustic adjustment unit according to Item 5.

  The invention according to claim 7 is the acoustic adjustment unit according to any one of claims 4 to 6, wherein a paper-made sound-absorbing sound-insulating plate is attached to at least one of the back surface and the front surface of the sound-absorbing reflecting plate. The invention according to claim 8 is the acoustic adjustment unit according to any one of claims 4 to 6, wherein the wooden rectangular frames 7 and 10 are adopted.

  According to the first aspect of the present invention, there is provided a sound-absorbing diffusion panel in which a plurality of cylindrical sound-absorbing diffusers formed by extending a paper folding core material are arranged in parallel in a rectangular frame while maintaining an appropriate distance from each other. A sound-adjusting unit with unique frequency characteristics can be obtained by combining the sound-absorbing diffusion action and the sound-absorbing and reflecting action of the sound-absorbing and reflecting panel in which the sound-absorbing and reflecting board is individually fitted in a rectangular frame. A plurality of different types of acoustic adjustment units are prepared, and the combination of these acoustic adjustment units can be easily changed and arranged, so that desired acoustic adjustment is easy. Furthermore, the light weight is advantageous in terms of movement and handling, and rearrangement and recombination are easy.

  In addition, as a sound absorbing diffuser arranged in the sound absorbing diffuser panel, a cylindrical sound absorbing diffuser in which a paper folding core material is stretched is adopted, so that the sound absorbing and diffusing action based on the material and shape of the sound absorbing diffuser itself is achieved. Not only is this remarkable, but also the resonant reflection absorption action with the adjacent members is synergistically added, and the sound absorption and diffusion action is improved. Furthermore, since the sound-absorbing diffuser is made of paper and has high hygroscopicity, it is desirable for maintaining the indoor humidity in an appropriate stable state, for acoustic adjustment, and for reducing damage to acoustic equipment. In addition, the configuration in which sound absorbing diffusers with cylindrical bias cores or honeycomb cores chamfered at both ends are arranged in parallel has a large decorative effect suitable for the environment where music is enjoyed due to the combination of the shape and the texture of the paper. is there.

  According to the invention of claim 2, the acoustic adjustment unit in which the sound absorption diffusion panel is detachably superposed in a sandwich state located in front of and behind the sound absorption reflection panel is used, and this is placed in front of the highly reflective wall surface. The arrangement is suitable for reverberation adjustment and soundproofing to the outside.

  According to the invention of claim 3, by using the acoustic adjustment unit in which the double-adsorbed sound-absorbing diffusion panel is superimposed on the front surface of the sound-absorbing reflection panel, the sound-absorbing diffusion effect is emphasized and combined with other acoustic adjustment units. You can adjust your favorite sound.

  According to the invention of claim 4, since the sound absorption diffusion panel and the sound absorption reflection panel are detachably superposed on the rectangular frame portion, recombination is thereby easy, and it is convenient for changing the type of the acoustic adjustment unit. Therefore, the degree of freedom of acoustic adjustment increases. In particular, the paper folding core material in the sound-absorbing diffusion panel is a sound-absorbing / diffusing surface whose entire peripheral surface is exposed by a bias core or a honeycomb core, and is made of paper with low smoothness and a shape having a remarkably large surface area. In combination, the sound absorption, diffusion, and sound insulation effects are great, so the sound absorption, diffusion, and sound insulation can be controlled based on the selection of the material and dimensions of the sound absorption diffuser, and the timbre and frequency characteristics can be changed. Is easy.

  According to the invention of claim 5, since the sound-absorbing diffuser formed by wrapping a foldable core material using corrugated cardboard as a waste paper raw material is applied to the shaft core, the smoothness of the paper surface formed thereby is small because of its high smoothness. In addition to providing a sound-absorbing effect, the production cost is low, and it is useful for recycling paper resources. Furthermore, the corrugated cardboard has a high hygroscopic property, so that the humidity in the room is maintained in an appropriate stable state, which is not only desirable for acoustic adjustment, but also helps to reduce damage to acoustic equipment.

  According to the invention of claim 6, in the sound absorption reflection panel, a sound absorption reflection panel having various frequency characteristics can be obtained by selecting and replacing an appropriate sound absorption reflection plate, and a combination of the sound absorption reflection panel and the sound absorption diffusion panel. Based on this, it is possible to easily obtain many kinds of acoustic adjustment units.

  According to the seventh aspect of the present invention, the paper sound-absorbing sound insulation plate is attached to at least one of the back surface and the front surface of the sound-absorbing reflection plate, so that the reflected sound behind the sound-absorbing reflection panel is moderately absorbed and relaxed. In addition to the effect of soundproofing to the outside, it is possible to suppress reverberation caused by the gap between the back surface of the acoustic adjustment unit and the rear wall surface, and to mechanically reinforce the sound absorbing reflector.

  According to the invention of claim 8, by making the rectangular frame in the sound-absorbing diffuser panel and the sound-absorbing / reflecting panel wooden, it is suitable for acoustic characteristics such as sound-absorbing / reflecting, and maintains strength despite its relatively light weight, and Processing is also easy.

  The results of the implementation of the acoustic adjustment device of the present invention are illustrated in FIGS. 11 and 12. FIG. 11 shows a case where, for example, a sound absorbing / reflecting panel having a relatively low sound absorbing property is adopted as the sound absorbing reflecting panel, and FIG. 12 is a case where a low absorbing property having a relatively high sound absorbing property is adopted, In either case, the sudden rise and fall of the sound is controlled so that the waveform is almost every minute, and it is recognized that it is easy to hear in the entire area.

  It is a partially broken schematic front view illustrating an acoustic adjustment device according to an embodiment of the present invention.   It is a partial front view of the sound-absorbing diffusion panel of FIG.   FIG. 3 is a cross-sectional plan view taken along line III-III in FIG. 2.   It is a partial front view of the sound-absorption reflective panel of FIG.   FIG. 5 is a cross-sectional plan view taken along line VV in FIG. 4.   It is a cross-sectional top view of the principal part which shows other two examples of a sound-absorbing reflection panel.   It is a top view which illustrates the combination of an acoustic adjustment unit.   It is operation | movement explanatory drawing of a sound adjustment unit.   It is an enlarged front view of only paper folding type core materials.   FIG. 10 is a transverse end view taken along line XX in FIG. 9.   4 is a graph illustrating an example of measuring acoustic characteristics according to the present invention.   4 is a graph illustrating an example of measuring acoustic characteristics according to the present invention.

  Hereinafter, the present invention will be described with reference to an embodiment shown in the accompanying drawings. For example, as shown in FIG. 1, a sound-absorbing diffusion panel 1 and a sound-absorbing reflection panel 2 are detachably polymerized, and an acoustic adjustment unit obtained by this polymerization 3 are juxtaposed side by side and / or sideways.

  As shown in FIGS. 2 and 3, the sound-absorbing diffuser panel 1 includes a sound-absorbing diffuser 6 formed by winding a paper folding core material 4 around a wooden shaft 5 in a cylindrical shape in a wooden rectangular frame 7. A plurality of lines are arranged side by side in a substantially parallel state while maintaining an appropriate distance from each other. The paper folding core material 4 is a bias core formed by using a cardboard base paper made of paper having a relatively high coefficient of friction (relatively low surface smoothness), for example, waste paper, as shown in FIGS. Alternatively, the honeycomb core is wound and fixed by means of adhesion or the like in a state where a large number of vertically slit-like holes are formed in the wooden shaft core 5. Furthermore, both ends of the sound-absorbing diffuser 6 are made into a conical shape with large chamfers, and the shaft core 5 is wound in a state of being divided into a plurality of stages, thereby improving the sound-absorbing action by increasing the surface area, and easy to manufacture and handle It is good to make it. Note that the core material 4 may be aligned in the horizontal direction for the arrangement in the rectangular frame 7, but as shown in FIG. 2, the core material 4 may be formed in a vertical staggered shape in which the adjacent core materials 4 are displaced from each other. This is desirable in the sense that the gap formed between the adjacent core members 4 is averaged.

Good results were obtained using 120 g / m ² corrugated cardboard as the paper folding core material 4. The cardboard paper was measured by a sliding angle test according to JIS-P-8147. As a result, the sliding angle was 25.1 in static friction and 23.2 in dynamic friction. As a test condition of the slip angle test, in a constant temperature and humidity chamber at 23 ° C. and 50%,
Load cell = 5kgf Range = 20% Load weight = 1001g
Test direction = vertical direction × vertical direction Speed = 10 mm / min
The test was conducted under the following conditions. The static friction coefficient and the dynamic friction coefficient were 468 and 430, respectively, on an average of three occasions.

  As a result of testing using various corrugated cardboards under the above conditions, it was found that a slip angle of 20 to 35 was desirable in static friction.

  According to the cylindrical sound-absorbing diffuser 6, the wall surfaces of the many slit-shaped holes are remarkably wide and the sound-absorbing action and the diffusing action are conspicuous because each wall surface is inclined in various different directions. . Further, when corrugated cardboard is used for the sound absorbing diffuser 6, since the surface smoothness is small, a higher sound absorbing effect can be obtained, the production cost can be reduced, and it is useful for recycling paper resources. Furthermore, the corrugated cardboard has a high hygroscopic property, so that the indoor humidity is kept in an appropriate stable state, which is not only desirable for acoustic adjustment but also effective for the maintenance of acoustic equipment.

  The dimensions of the sound-absorbing diffuser 6 are preferably, for example, a diameter of several tens of mm and a length of about several hundred mm, and are provided in a plurality of stages under a state where the shaft core 5 is divided into hundreds of tens of mm. In addition, the gap C1 between the sound absorbing diffusers 6 and the gap C2 between the peripheral surface of the sound absorbing diffuser 6 and the rectangular frame 7 are used as sound absorbing and reflecting passages, and these are formed to about 10 to several tens of millimeters. As for the size of the opening of the hole in the paper folding core material 4, those having a major axis of several tens of mm and a minor axis of about several mm are suitable in terms of the sound absorption and diffusion effect and manufacturing convenience. The wooden rectangular frame 7 is desirable because the use of a hard solid material such as teak, rose, walnut, mahogany has mechanical strength and a high-class feeling. Further, in addition to forming a fitting protrusion 8 on the front end edge of the square frame 7, a rear end edge is formed with a fitting groove 9 coinciding with the fitting protrusion 8, and the sound absorbing diffusion panel 1 and the sound absorbing reflection panel 2 are formed. When the two are superposed, or when the sound absorbing diffusion panels 1 are superposed one another. As a material of the rectangular frame 7, paper material or hard magnesium material may be used in addition to the wood.

  The shape of the paper folding core material 4 in the sound-absorbing diffusion panel 1 is an aggregate of polygonal slit-shaped holes that gradually expand in the outer circumferential direction, so that the incident sound from the sound source is absorbed by itself. In addition to the diffusion and resonance reflection absorption with the adjacent member, the sound absorption and sound insulation effects are controlled to cause a change in timbre and frequency characteristics, which are reflected as converted sound and diffused sound.

  As shown in FIGS. 4 and 5, the sound-absorbing diffuser panel 2 has the same height and width as the sound-absorbing diffuser 6 so that the sound-absorbing diffuser 6 can be fitted in a superposed state before and after the rectangular frame 7 in the sound-absorbing diffuser 6. A rectangular frame made of the same material and having the same dimensions is employed, and the same fitting protrusion 8 and fitting groove 9 as in the rectangular frame 7 are formed in the front end edge and the rear end edge so as to coincide with each other. The rectangular frame 10 is adopted, and the block 11 is fitted into the wooden rectangular frame 10 at the entire peripheral edge near the rear end or a part of the opposing peripheral edge, and the sound absorbing sound insulating plate 12 and the sound absorbing reflecting plate are made of paper. 13 is inserted into the immovable state in a detachable manner so as to abut against the blocking piece 11 under the state of being laminated.

  As the paper sound-absorbing sound insulation board 12, a semi-chemical pulp is used, and a sandwich in which a large number of independent air chambers are formed by adhering paper pieces to both sides of a plate-like core material such as a bias core, honeycomb core, or feather core. Adopt structure. It is a reinforcing material for the sound-absorbing reflection plate 13, and absorbs sound reflected from the wall surface and sound reflected from the wall surface by the independent air chamber, and has a sound insulation and soundproofing action. In addition, the position where the sound absorbing sound insulating plate 12 is provided may be at least one of the back surface and the front surface of the sound absorbing reflector plate 13 in the sense of reinforcing the sound absorbing reflector plate 13; Thus, when the sound-absorbing and sound-insulating plate 12 is provided on the front surface of the sound-absorbing and reflecting plate 13, the sound-absorbing property is increased.

  The sound-absorbing reflection plate 13 is any one of a hard magnesium plate, a foamed magnesium plate, a wood plate, and a rock wool plate, or a laminate of two or more thereof. The hard magnesium plate is a plate material mainly composed of magnesium hydroxide, magnesium oxide, and magnesium chloride, and further including silicon dioxide, calcium oxide, sodium oxide, etc., and is manufactured into a plate shape by extrusion molding. High reflectivity and relatively low sound absorption. The foamed magnesium plate is the same as the constituent material of the hard magnesium plate, but is foamed in the process of forming into a plate shape by adding a foaming agent, and has high sound absorption and low reflectivity. Naturally, the sound absorption and reflectivity also change depending on the thickness.

  The ratio of the main materials such as hard magnesium plate and foamed magnesium plate is 43% magnesium hydroxide, 36% magnesium oxide, 13% magnesium chloride, other silicon dioxide, calcium oxide, sodium oxide, etc. Is less than several percent. These ratios are not limited to these values, and can be appropriately changed from the viewpoint of sound absorption and reflectivity.

  The sound-absorbing reflection plate 13 is preferably a solidified glass sheet after extrusion molding by enclosing a glass fiber woven fabric or net for mechanical strength reinforcement. The thickness may be selected from 3 to several tens of millimeters, but it is appropriate to adjust the sound-absorbing reflection characteristics by adopting a thin one and increasing or decreasing the number.

  The wood used for the sound-absorbing reflector 13 is selected not only because the hardness varies depending on the type, but also because the hardness varies depending on the same type, and the difference in sound-absorbing property and reflectivity also depends on the smoothness of the surface. The range is relatively wide, and it is convenient in design which one is adopted. Naturally, the sound-absorbing property and the reflecting property of the rock wool plate change depending on the density and thickness.

  FIG. 8 is an explanatory diagram of the operation of the acoustic adjustment unit 3. Sound from the sound source is diffused by the sound absorbing diffuser 6, and the diffused sound is mixed with the adjacent sound absorbing diffuser 6 or the inner wall surface of the wooden rectangular frame 7. Resonant reflection is absorbed between. On the other hand, the sound that has passed through the gap C1 and the gap C2 is absorbed and reflected by the sound absorbing reflector 13. A part of the reflected sound is folded back and passes through the gap C1 and the gap C2, and the other reflected sound is further absorbed and diffused by the sound absorbing diffuser 6 and passes through the gap C1 and the gap C2. As a result, the sound is reflected as a converted sound and a diffused sound that are acoustically adjusted by the sound absorbing and diffusing panel 1 and the sound absorbing and reflecting panel 2.

  In the case of FIG. 5 in which, for example, a foamed magnesium plate or a rock wool plate having a high sound absorbing effect is adopted as the sound absorbing reflector 13, unnecessary low-frequency sound is generated under the cooperation of the sound absorbing diffuser panel 1 and the sound absorbing reflector panel 2. The sound can be reflected and converted as diffused sound from the gap C1 and the gap C2 in the sound-absorbing diffusion panel 1 in a state in which the necessary low-frequency sound is optimized.

  In the case of FIG. 6A in which, for example, a wood plate having a good balance between the sound absorption effect and the reflection effect or a magnesium plate having a relatively high sound absorption effect is adopted as the sound absorption reflection plate 13, cooperation between the sound absorption diffusion panel 1 and the sound absorption reflection panel 2 Based on this, it is possible to balance the low to high range, promote the activation of the sound, convert it into a pleasant tone and reflect it.

  Further, in the case of FIG. 6B in which, for example, a hard magnesium plate having a high reflection effect is adopted as the sound absorbing reflection plate 13, under the cooperation of the sound absorbing diffusion panel 1 and the sound absorbing reflection panel 2, due to the adverse effect of the installation environment. By reflecting and diffusing the lost sound, it can be reflected as a timbre closer to the sound source.

  The sound effect of the sound absorbing reflector 13 has been described with reference to the above three examples. However, the range of sound absorbing properties and reflectivity can be set broadly by selective exchange from among the various sound absorbing reflectors 13. The sound range and timbre can be changed in multiple steps, and the sound from the sound source can be variously converted and diffused in cooperation with the sound absorbing diffuser 6. In addition, by selecting the superposition form of the sound absorbing diffusion panel 1 and the plurality of types of sound absorbing reflection panels 2, a larger number of types of acoustic adjustment units 3 can be obtained. Therefore, by selectively arranging a plurality of types of acoustic adjustment units 3, Desired room tuning can be realized.

DESCRIPTION OF SYMBOLS 1 Sound absorption diffusion panel 2 Sound absorption reflection panel 3 Sound adjustment unit 4 Paper folding core material 5 Axle core 6 Sound absorption diffuser 7 Rectangular frame 8 Fitting protrusion 9 Fitting groove 10 Square frame 11 Block 12 Sound insulation board 13 Sound absorption board Reflector C1, C2 gap

Claims (8)

  A sound-absorbing diffuser (6) in which a paper folding core material (4) such as a paper bias core or a paper honeycomb core is formed into a stretched cylindrical shape is almost kept in a square frame (7) with a proper distance from each other. A plurality of sound-absorbing diffuser panels (1) arranged in parallel are prepared, and sound-absorbing reflectors (13) having different ratios of sound-absorbing properties and reflecting properties are individually fitted in the rectangular frame (10). A plurality of types of sound-absorbing reflection panels (2) are prepared, and the sound-absorbing / diffusing panel (2) and the sound-absorbing / reflecting panel (2) selected from the plurality of types are arranged on the back side of the sound-absorbing / diffusing panel (1). It is characterized in that it is detachably polymerized under the condition located at the position, and the acoustic adjustment unit (3) obtained by this polymerization is used, and a single type is arranged side by side or a plurality of types are arranged side by side. An acoustic adjustment device.   The sound-absorbing diffusion panel (1) is detachably polymerized in a sandwich state located before and after the sound-absorbing / reflecting panel (2), and the acoustic adjustment unit (3) obtained by this polymerization is used to make a single species. The acoustic adjustment device according to claim 1, wherein the acoustic adjustment devices are arranged in parallel or in combination of a plurality of types.   Use the acoustic adjustment unit (3) in which the double-absorbed sound-absorbing diffuser panel (1) is superposed on the front surface of the sound-absorbing / reflecting panel (2). The acoustic adjustment device according to claim 1, wherein:   A sound-absorbing reflection panel (2) in which a sound-absorbing reflection plate (13) is fitted in a rectangular frame (10) and a paper folding core material (4) such as a paper bias core or a paper honeycomb core are formed into a stretched cylindrical shape. An acoustic adjustment unit in which the formed sound absorbing diffuser (6) is detachably superposed on a plurality of sound absorbing diffuser panels (1) arranged in parallel in a substantially rectangular state within a rectangular frame (7).   The sound adjustment unit according to claim 4, wherein a sound absorbing diffuser (6) is used in which a foldable core material (4) using a corrugated cardboard raw material is wound around the shaft core (5).   The acoustic adjustment unit according to claim 4 or 5, wherein any one of a hard magnesium plate, a foamed magnesium plate, a wood plate, and a rock wool plate or a laminate of two or more thereof is adopted as the sound absorbing reflector (13). .   The sound adjusting unit according to any one of claims 4 to 6, wherein a paper sound absorbing sound insulating plate (12) is attached to at least one of the back surface and the front surface of the sound absorbing reflecting plate (13).   The acoustic adjustment unit according to any one of claims 4 to 6, wherein the wooden rectangular frames (7) and (10) are adopted.

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