Sound absorbers and sound absorbing structures

Abstract

To provide a sound absorber or a sound absorption structure which is not affected by a dimension of a finishing material even if it is stored in the finishing material of a ceiling face and the like and can adjust a resonance frequency even if it is installed outside the ceiling face and the like.SOLUTION: A sound absorber body 20 includes an inner slit 23 and a cavity 3 connected to the inner slit, connects the inner slit with a space and absorbs sound in the space. A neck member 30 in which a neck is formed outside and / or inside the inner slit by attaching it near the inner slit is provided. Thus, a neck height L and / or a neck slit width b can be changed by attaching / detaching the neck member.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a sound absorber and a sound absorbing structure. More specifically, the present invention relates to a sound absorber and a sound absorbing structure using the same, which includes a sound absorber body that is installed inside at least one of a ceiling surface, a wall surface, or a floor surface facing a space, and a structure installed in the space (hereinafter referred to as a "ceiling surface, etc."), or is exposed inside the space, and the sound absorber body has an inner slit and a cavity that communicates with the inner slit, and the inner slit is connected to the space to absorb sound in the space. [Background technology]

[0002] As an example of the sound absorber and sound absorbing structure as described above, the one described in the following Patent Document 1 is known. This sound absorber is configured to form a Helmholtz resonator and absorb sound by resonating through an opening 102. The resonator described in this document has different resonance frequencies depending on the volumes of the cavities 4 and 5 and the width of the opening 102, etc., and therefore different sound absorption frequency bands.

[0003] Incidentally, when a sound absorber is attached to a ceiling as shown in Figures 5 and 6 of the document, and a ceiling board 46 is further attached around the opening 102, a neck is formed around the opening 102 depending on the thickness of the ceiling board, and the height of this neck and the width of the slit facing the opening 102 determine the height of the neck and the width of the slit. In that case, the resonance frequency of the resonator differs from the initial design, and there is a problem that the desired sound absorption performance cannot be achieved. Also, there has been a demand for a sound absorber whose resonance frequency can be adjusted appropriately according to the environment. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-188954 A Summary of the Invention [Problem to be solved by the invention]

[0005] In view of the above-mentioned conventional situation, the present invention aims to provide a sound absorber and sound absorbing structure which is not affected by changes in resonant frequency due to the dimensions of finishing materials for a ceiling surface, etc., even when stored inside the ceiling surface, etc., and which allows the resonant frequency to be adjusted even when installed outside the ceiling surface, etc. [Means for solving the problem]

[0009] In order to achieve the above-mentioned object, a sound absorber according to the present invention is characterized in that it comprises a sound absorber main body that is installed inside or exposed within the space on at least one of a ceiling surface, a wall surface or a floor surface facing a space, and a structure to be installed within the space (hereinafter referred to as a "ceiling surface, etc."), and the sound absorber main body has an internal slit and a cavity that communicates with the internal slit, and is configured to absorb sound within the space by connecting the internal slit to the space, and further comprises a neck member that forms a neck outside and / or inside the internal slit by being attached near the internal slit, and the neck member comprises a first neck and a second neck of different lengths joined at a 90 degree angle, and either the first or second neck is attached near the internal slit as a fixed part and the other is used as the neck, and the neck height and neck slit width can be changed by selecting either the first or second neck for use as a neck and by changing the attachment position.

[0010] Additionally, there may be an inner neck portion extending into the cavity from the inner slit.

[0011] In the above configuration, a sealing material may be provided to cover the path from the inner slit of the neck member to the inside of the sound absorber body, the sealing material preventing visual observation of the inside of the inner slit without impairing sound absorption properties, and the neck member may have a neck portion and a fixing portion bent at approximately 90 degrees, and a step portion for receiving the sealing material may be formed between the neck portion and the fixing portion. This configuration can prevent foreign objects from being inserted into the inner slit from the outside, and can also improve the design as seen from the outside. Since the sealing material is received in the step portion, it is easy to replace the sealing material even if it is damaged.

[0012] In addition, a flow resistance material that absorbs sound may be provided inside the cavity near the inner slit and oriented toward the back of the inner slit, and the width of the inner slit may be formed wider than the neck slit width. With this configuration, the neck portion of the neck member can be expanded to the width of the inner slit, making it easier to adjust the range of the resonance frequency adjustment. Moreover, since the inner slit portion can be formed wide, there is an advantage that it is easier to insert a flow resistance material such as a sound absorbing material using the inner slit.

[0013] The flow resistive material may be provided on both sides of the inner slit, and a cavity may be located behind each of the flow resistive materials. The sound absorber can be stored and arranged rationally by effectively utilizing the space in the ceiling, behind the wall, etc. Also, the flow resistive material may be provided on only one side of the inner slit, and a cavity may be located only behind the flow resistive material. This configuration makes it easier to install the sound absorber even in an environment where there is no storage space on one side of the ceiling or behind the wall due to a slab.

[0014] Furthermore, a spacer may be provided between the neck member and the sound absorber body to change the neck height and / or the neck slit width. With this configuration, the resonant frequency can be accurately adjusted using the spacer.

[0015] On the other hand, a sound absorbing structure using a sound absorber according to any of the above configurations is characterized in that the sound absorber body is stored inside a ceiling surface or the like, and the neck protrudes from a slit formed in the surface finishing material. According to this configuration, the neck can be installed independently regardless of the thickness of the surface finishing material, so that a sound absorbing structure can be constructed with a desired resonance frequency. Therefore, it is now possible to freely set and design the spacing of the slits in the surface finishing material independently of the neck. Effect of the Invention

[0016] According to the features of the sound absorber and sound absorbing structure of the present invention, even when the sound absorber and sound absorbing structure are stored inside a ceiling surface or the like, they are not affected by the dimensions of the finishing material of the ceiling surface or the like, and the resonant frequency can be adjusted even when the sound absorber and sound absorbing structure are installed outside a ceiling surface or the like.

[0017] Other objects, configurations and effects of the present invention will become apparent from the following detailed description of the preferred embodiments of the present invention. [Brief description of the drawings]

[0018] [Figure 1] FIG. 2(a) is a vertical cross-sectional view of a sound absorbing structure in which a sound absorber according to the present invention is installed in a ceiling corner, and FIG. 2(b) is an enlarged cross-sectional view of the sound absorber. [Figure 2a] 4 is a graph showing the sound absorption characteristics of a sound absorber according to the present invention, in which the neck height l and the neck slit width b are changed. [Figure 2b] 1 is a graph showing the sound absorption characteristics of a sound absorber according to the present invention, in which the neck slit width is 15 mm and the neck height l is changed. [Figure 2c] 1 is a graph showing the sound absorption characteristics of a sound absorber according to the present invention, in comparison with other sound absorption techniques when the neck slit width b is changed. [Diagram 3] 1 is a cross-sectional view of a sound absorbing structure in which a sound absorber according to the present invention is housed in the center of a wall surface. [Figure 4] 1 is a cross-sectional view of a sound absorbing structure in which a sound absorber according to the present invention is stored in a corner of a wall surface. [Diagram 5] 1 is a vertical cross-sectional view of a sound absorbing structure in which a sound absorber according to the present invention is stored in a lower corner of a wall surface. [Figure 6] FIG. 2A is a perspective view showing the installation location of a sound absorber according to the present invention with a neck slit, and FIG. 2B is a schematic perspective view showing the relationship between the volume of the sound absorber body and the dimensions of the neck portion. [Figure 7]FIG. 11 is a longitudinal cross-sectional view showing various mounting configurations between a sound absorber and a neck member according to the present invention, in which (a) is when a first neck is used, (b) is when a second neck is used, (c) is when the first neck is used with a width spacer, and (d) is when the first neck is used in addition to using a depth spacer. [Figure 8] FIG. 11 is a longitudinal cross-sectional view of an embodiment of a sound absorber according to the present invention in which a step is provided in the neck member, (a) being a basic form in which a step is provided, (b) being a form in which three neck portions are provided, in which the first neck is used, and (c) being a form in which the second neck is used. [Figure 9] FIG. 1(b) is a cross-sectional view showing a modified example of the sound absorber shown in FIG. 1(b), where (a) is a case where the inner surfaces of the inner neck portion 25 and the neck portion 31 are aligned, and (b) is a case where the slit of the neck portion 31 is narrower than that in (a). [Figure 10] 1(b), where (a) is a cross-sectional view showing a modification of the sound absorber shown in FIG. 1(b), where (b) is a cross-sectional view showing a modification in which only an inner neck portion 39 is provided, and (b) is a cross-sectional view showing a modification in which both an inner neck portion 39 and a neck portion 31 are provided. [Figure 11] 1(b), where (a) is a cross-sectional view showing a modified example of a protrusion for fixing a sound-absorbing material, and (b) is an example in which a neck portion 31 of a different shape is provided. [Figure 12] FIG. 11 is a longitudinal cross-sectional view showing another form in which the sound absorber body is made from multiple parts. (a) is an example in which the sound absorber body is divided into seven parts, (b) is an example in which the sound absorber body is divided into seven different parts, and (c) is an example in which the sound absorber body is divided into three parts. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Next, the present invention will be described in more detail with reference to the accompanying drawings, FIGS. 1 to 6 as appropriate.

[0020] The sound absorber 2 according to the present invention shown in Fig. 1 is installed in an indoor structure 100 shown in Figs. 1 and 6(a), for example, to constitute a sound absorbing structure 1. In the indoor structure 100 in Fig. 6(a), a ceiling board 107, an interior wall board 113, a floor slab 120, and a support 130 are shown. References I, III, IV, and V shown in the figure indicate the positions of the neck slits 32 corresponding to the mounting forms in Figs. 1, 3, 4, and 5, respectively. Each sound absorber is stored in the internal space of a surface finishing material such as the ceiling board 107 or the interior wall board 113, and a neck (to be described later) protrudes from the slit of the surface finishing material. Alternatively, the sound absorber may be stored in the internal space shown in the positions indicated by references XI, XII (when a floor board is provided apart from the floor slab instead of the floor slab 120), and XIII. In addition, a sound absorber may be installed alone outside the surface finishing material at the position shown by symbol XIII, and similarly, sound absorbers may be installed alone outside the surface finishing material at the positions shown by symbols I, III, IV, V, XI, and XII.

[0021] As shown in Fig. 1, the sound absorber 2 is composed of a sound absorber body 20 and a neck member 30, both of which are long in the direction perpendicular to the page, with a sealing material 6 provided between these two members. Note that the sound absorbing performance is not affected even if the sealing material 6 is not provided. The sound absorber body 20 has a hollow portion 3 inside, and contains a pair of sound absorbing materials 5, 5 that act as flow resistance materials.

[0022] The sound absorber body 20 is symmetrical about a central inner slit 23, with opening side protrusions 21a, 21a on the left and right of the opening side plate portion 21, and rear side inner protrusions 22b, 22b and rear side outer protrusions 22a, 22a on the left and right of the rear side plate portion 22, with a pair of left and right sound absorbing materials 5, 5 being held by each protrusion. A cavity is located behind each of the sound absorbing materials 5, 5, forming a double-sided sound absorber body 20A.

[0023] In this embodiment, the neck member 30 has an L-shaped angle, and the neck portion 31 and the fixing portion 33 are joined at an angle of 90 degrees. The neck slit 32 is formed between the neck portions 31, 31 of the pair of neck members 30, 30 fixed to the opening side plate portion 21 by the fixing portion 33. A sealing material 6 is interposed between the opening side plate portion 21 and the fixing portion 33, and these are all attached with, for example, an adhesive. The opening side plate portion 21 and the fixing portion 33 may be fixed by driving screws into both of them. The sealing material 6 is made of, for example, a metal mesh, a glass fiber cloth, a nonwoven fabric, etc., and is made of a material that covers the inner slit 23 and prevents the inside of the inner slit 23 from being seen without impairing the sound absorption. If it is acceptable to see the internal structure, the sealing material 6 does not need to be attached.

[0024] The inner slit 23 is cut out wider than the distance between the inner protrusions 22b, 22b on the far side, making it easy to insert and install the sound absorbing material 5. The neck slit width b of the neck slit 32 can be adjusted by widening it to the maximum width of the inner slit 23. The neck portion 31 and the fixing portion 33 have different lengths, and if they are inverted to become the first neck 30a and the second neck 30b, respectively, the neck height l can be adjusted.

[0025] The sound absorber 2 is made up of the sound absorber body 20, the sealing material 6, and the neck member 30, which are all long in the direction perpendicular to the paper. In the example of FIG. 6(a), the slit is set to be formed over almost the entire width of the ceiling, and the neck slit length is indicated by the symbol a. The length can be stopped midway. However, the end of the neck part needs to be blocked by another member, like the neck member 30, as indicated by the symbol 31e in FIG. 6(b). That is, both ends of the entire length need only be blocked at the very least with a plate material that follows the outline of the sound absorber body 20 and the neck member 30 in FIG. 1, but a short member like the neck member 30 may be provided perpendicular to the neck member 30, and both ends of the sound absorber body 20 may also be blocked with another plate material. Of course, the neck slit length a is not limited to the entire width of the room, and may be stopped midway.

[0026] The indoor structure 100 in which the sound absorber 2 is installed will be further explained. A hanging bolt 101 supported by a ceiling slab supports a sill support 103 extending in a direction perpendicular to the paper surface via a hanger 102, and a sill 104 is attached perpendicularly, and a ceiling board 107 is attached to the sill 104. Between the mounting channel 106 attached to the foundation wall board 112 and the sill support 103, mounting angles 105 are intermittently provided in a direction perpendicular to the paper surface, and the sound absorber body 20 is attached below the mounting angle 105. A runner 110 is provided at the bottom of the mounting channel 106, extending in a direction perpendicular to the paper surface, and studs 111 are erected intermittently in a direction perpendicular to the paper surface below the runner 110, and an interior wall board 113 is supported by the studs 111. In this example, since there is space behind both the interior wall board 113 and the ceiling board 107, a double-sided sound absorbing sound absorber body 20A is used.

[0027] Figure 2 shows an example of the effect of changing the resonance frequency of the sound absorber with the above-mentioned configuration. The horizontal axis shows the 1 / 3 octave band center frequency (Hz), and the vertical axis shows the sound absorption coefficient using the reverberation room method. The neck height l and neck slit width b were changed. In Figure 2a, the circles indicate l: 10mm, b: 10mm, and the triangles indicate l: 20mm, b: 10mm. By increasing the neck height l, the resonance frequency f 0 Shift to the low frequency side to increase the sound absorption rate in the low frequency range, and the resonance frequency f 0 The square marks indicate l: 35 mm, b: 15 mm, and the increase in the neck slit width b, combined with the increase in the neck height l, increases the resonance frequency f 0 It can be seen that the center of gravity of the graph integral value has shifted further to the lower frequency side.

[0028] In Fig. 2b, the circles indicate l: 20mm and b: 15mm, and the triangles indicate l: 35mm and b: 15mm. By increasing the neck height l, the center of gravity of the graph integral and the resonance frequency f 0 It can be seen that the frequency has shifted to the lower range.

[0029] In Fig. 2c, the circle marks are l: 20 mm, b: 20 mm, and the triangle marks are l: 20 mm, b: 10 mm. For example, by reducing the neck slit width b, the resonant frequency f 0 The square rock wool sound absorbing boards and diamond tile carpets can be used to supplement any deficiencies and selectively absorb the main frequency ranges at conversation levels.

[0030] Fig. 3 shows an example in which a slit is formed in an inner wall board 113 at position III in Fig. 6(a) to house the sound absorber 2. Studs 111 extend in the direction perpendicular to the plane of the paper, and by similarly arranging the double-sided sound absorber body 20A along the studs 111, sound-absorbing slits can be formed in the wall surface along the top and bottom of the space.

[0031] Fig. 4 shows an example in which a sound absorber 2 is housed in a slit formed in the corner where the interior wall boards 113, 113 intersect at right angles at position IV in Fig. 6(a). In this example, a one-sided sound absorbing body 20B is used, and it can be installed particularly well when, for example, there is no stud 111 on the left side and the interior wall board 113 is close to the wall slab 114. Therefore, when there is a space on the left side, a two-sided sound absorbing body 20A such as the part indicated by reference symbol 20C may be used.

[0032] An L-angle neck member 30, similar to the previous embodiment, is used on the right side of the inner slit 23, but a flat neck member 35 is used on the left side of the inner slit. Since the left-side inner wall board 113 can form part of the neck, the flat neck member 35 may be used for design purposes in addition to homogenizing the material of the neck. In this example, the left end of the sealing material 6 is bent and attached to the outer wall of the sound absorber body 20.

[0033] Fig. 5 shows an example in which a sound absorber 2 is housed in a slit formed in the corner where the lower end of the interior wall board 113 and the floor slab 120 intersect at right angles at position V in Fig. 6(a). In this example, a one-sided sound absorber body 20B is used as in the previous example, and the side where the inner slit 23 is formed is in contact with the floor slab 120, thereby using the floor slab 120 as part of the neck.

[0034] A lower runner 121 is arranged on top of the sound absorber body 20, extending along the sound absorber body 20 in a direction perpendicular to the plane of the drawing, and a stud 111 is provided on top of the lower runner 121, to which an inner wall board 113 is fixed.

[0035] FIG. 7 shows a modified example of the neck member 30. In FIG. 7(a), the neck portion 31 and the fixed portion 33 are provided with turn-back portions 34 at 90 degrees each other, and the lengths of the neck portion 31 and the turn-back portions 34 are different to form the first and second neck portions 30a and 30b. By using the second neck portion 30b as shown in FIG. 7(b), it is possible to adjust the neck height l from l1 to l2 lower with more reliable dimensional accuracy than when the first neck portion 30a is used. As shown in FIG. 7(c), by inserting a width spacer 36 between each turn-back portion 34 (or the portion indicated by the reference numeral 31 when inverted) and the side surface of the sound absorber main body 20, the neck width b can be expanded by the thickness 2ΔW. Furthermore, by inserting a depth spacer 37 between the fixed portion 33 and the lower surface of the sound absorber main body 20 as shown in FIG. 7(d), the neck height l can be expanded by the thickness Δt of the depth spacer 37.

[0036] 8 shows a modified example for making the sealing material 6 replaceable, in which a step 38 is provided between the neck portion 31 and the fixing portion 33, and the sealing material 6 is stored in this step 38 and attached to the sound absorber body 20. With this configuration, the sealing material 6 is not sandwiched between the fixing portion 33 and the sound absorber body 20, so it is easy to replace it via the neck slit 32. Figures 8(b) and 8(c) show a configuration in which the folded-back portion 34 is provided in addition to the step 38, and the neck height l can be changed to l1 or l2 by reversing the first and second neck portions 30a and 30b as in the previous embodiment.

[0037] 9 shows a modified example of the sound absorber shown in FIG. 1(b), where (a) shows a case where the inner surfaces of inner neck portion 25 and neck portion 31 are flush with each other. Inner neck portion 25 fits inward at a position corresponding to rear inner protrusion 22b, and together with neck portion 31 of neck member 30, the neck height is l. A portion of sound absorbing material 5 is fixed by inner neck portion 25. Volume V in the previous equation 3 is calculated as the following equation 4, since the volume of inner neck portion 25 is excluded.

[0038] formula 4 V=A*B*La*b2*l2 V: cavity volume, A: cavity length, B: cavity width, L: cavity height, a: neck slit length, b: neck slit width, l: neck height, b2: inner neck outer width, l2: inner neck height

[0039] In this example, the inner neck portions 25 are fixed and cannot be adjusted, but if the sound absorber body 20 is divided as shown in Figures 12(b) and (c) below, the spacing between the inner neck portions 25 can be adjusted. In this example, the neck member 30 is provided separately, making it possible to change the neck slit width b and neck height l.

[0040] In Fig. 9(b), in addition to the inner neck portion 25, an inner protrusion 21b on the opening side is provided to hold the sound absorbing material 5. The slit of the neck portion 31 is narrower than that in Fig. 9(a), and the narrowest part is the neck slit width b.

[0041] In FIG. 10, inner neck portion 39 is a separate member from sound absorber body 20, and in FIG. 10(a), it can be inverted into first neck 39a and second neck 39b, and the neck slit width b can also be adjusted.

[0042] 10(b) shows a case where both an inner neck portion 39 and a neck portion 31 are provided. In addition to the inner neck portion 39, an opening-side inner protrusion 21b is provided to hold the sound-absorbing material 5. When providing the sealing material 7, in addition to a sealing sheet 7a similar to the previous sealing material 6, sound-absorbing materials 7b and 7c made of the same material as the previous sound-absorbing material 5 may be provided in the neck slits 32.

[0043] Figure 11(a) shows a modified example of a protrusion for fixing the sound-absorbing material, in which a pair of opening side central protrusions 21c and a pair of rear side central protrusions 21c are directed opposite each other on the opening side plate portion 21 and the rear side plate portion 22, and each protrusion 21c, 22c bites into the widthwise center of the sound-absorbing material 5 to fix the sound-absorbing material.

[0044] 11(b) shows an example in which a neck portion 31 of a different shape is provided, which has a step portion 31c between a narrow neck portion 31a and a wide neck portion 31b. The narrow neck portion 31a has a neck slit width b.

[0045] In the above embodiment, the sound absorber body 20 is integrally formed by extrusion molding or the like in the direction perpendicular to the page, but it may also be constructed by combining multiple parts as shown in Fig. 12. In Fig. 12(a), the sound absorber body is divided into seven parts, with one channel part 20a combined with two angle parts 20b to create the main part, and inside it, small channels 20c and small angles 20d are combined to form the protrusions of the sound absorbing material 5.

[0046] In Fig. 2(b), the sound absorber body is divided into seven different parts, with two large channel sections 20f and two small channel sections 20g connected by a flat plate 20h. At the front, the large channel section 20f and the small channel section 20g are each connected by a neck member 30. Fig. 2(c) shows an example in which the sound absorber body is divided into three parts. Two large channel sections 20f with protrusions 21ab and 22ab are connected by a flat plate 20h.

[0047] The present invention can be modified in various ways without departing from the spirit of the present invention, and the above-described embodiments can be combined with each other, for example, by combining the examples of FIGS. [Industrial Applicability]

[0048] The present invention can be used as a sound absorber and sound absorbing structure that can be installed as an existing or additional installation on at least one of the ceiling, wall or floor surfaces facing a space, and on structures to be installed in the space (wood boards, metal, glass, stone, tiles, etc.). It can also be installed exposed on the outside of the surface finishing material in the above-mentioned space to adjust the acoustic environment by absorbing sound. It can absorb sound in the frequency range where the sound absorbing power of conventionally used finishing sound absorbing materials (glass wool, rock wool sound absorbing boards, etc.) is insufficient, and also in the main frequency range of human conversation level, and can be used as a base material for various materials. [Explanation of symbols]

[0049] 1: sound absorbing structure, 2: sound absorber, 3: cavity, 5: sound absorbing material, 6: sealing material, 7a: sealing sheet, 7b, 7c: sound absorbing material, 7: sealing material, 20: sound absorber body, 20A: double-sided sound absorbing sound absorber body, 20B: single-sided sound absorbing sound absorber body, 21: opening side plate portion, 21a: opening side protrusion, 21b: opening side inner protrusion, 21c: opening side central protrusion, 22: side plate portion, 22a: rear side outer protrusion, 22b: rear side inner protrusion, 21c: rear side central protrusion, 23: inner slit, 25: inner neck portion, 30: neck member, 30a: first neck, 30b: second neck, 31: neck portion, 31a: thin neck portion, 31b: thick neck portion, 31c: step portion, 32: neck slit, 3 3: fixing part, 34: folded part, 35: flat neck member, 36: width spacer, 37: depth spacer, 38: step part, 39: inner neck part, 39a: first neck, 39b: second neck, 100: indoor structure, 101: hanging bolt, 102: hanger, 103: sill support, 104: sill, 105: mounting angle, 106: mounting channel, 107: ceiling board, 110: runner, 111: stud, 112: foundation wall board, 113: interior wall board, 114: wall slab, 120: floor slab, 121: lower runner, 130: support, B: cavity width, a: neck slit length, b: neck slit width, L: cavity height, l: neck height

Claims

1. A sound absorber comprising: a sound absorber body that is installed in at least one of a ceiling surface, a wall surface, or a floor surface facing a space, and a structure installed in the space (hereinafter referred to as a "ceiling surface, etc."), or that is exposed in the space, the sound absorber body having an inner slit and a cavity that communicates with the inner slit, and the inner slit communicates with the space to absorb sound in the space, The sound absorber further includes a neck member that forms a neck outside the inner slit by being attached near the inner slit, the neck member comprising a first neck and a second neck of different lengths joined at a 90 degree angle, one of the first and second necks being attached near the inner slit as a fixed part and the other being used as the neck, and the neck height and neck slit width being changeable depending on the selection of whether the first or second neck is used as a neck and the attachment position.

2. 2. The sound absorber of claim 1, further comprising an inner neck portion extending into the cavity from said inner slit.

3. 2. The sound absorber of claim 1, wherein a sealing material is provided to cover the path from the inner slit of the neck member to the inside of the sound absorber body, the sealing material preventing visual inspection of the inside of the inner slit without impairing sound absorption properties, the neck member having a neck portion and a fixing portion that is bent approximately 90 degrees, and a step portion that accepts the sealing material is formed between the neck portion and the fixing portion.

4. 4. A sound absorber as described in claim 1, wherein a flow resistance material for absorbing sound is provided inside the cavity near the inner slit and oriented toward the back of the inner slit, and the width of the inner slit is formed wider than the width of the neck slit.

5. 5. The sound absorber according to claim 4, wherein the flow resistive material is provided on both sides of the inner slit, and a cavity is located deep inside each of the flow resistive materials.

6. 5. The sound absorber according to claim 4, wherein the flow resistive material is provided on only one side of the inner slit, and a cavity is located only behind the flow resistive material.

7. 7. The sound absorber according to claim 1, further comprising a spacer that can be inserted between the neck member and the sound absorber body to change the neck height and / or the neck slit width.

8. 7. A sound absorbing structure using the sound absorber according to claim 1, wherein the sound absorber body is stored inside a ceiling surface or the like, and the neck is protruded from a slit formed in a surface finishing material.

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