Sound insulation structure for a garment

Abstract

A sound insulation structure for a garment is disclosed. The sound insulation structure includes a first layer comprising a sound absorbing material, and a second layer configured to be at least one of sound reflecting and sound diffusing.

Claims

1. A sound insulation structure for a garment, the sound insulation structure comprising: a first layer comprising a sound absorbing material; and a second layer attached to the first layer, the second layer configured to be at least one of sound reflecting and sound diffusing, wherein at least one of the first layer and the second layer comprises a mesh, and wherein the sound insulation structure forms at least a part of the garment.

2. The sound insulation structure of claim 1, wherein the first layer and the second layer at least partially overlap.

3. The sound insulation structure of claim 1, wherein the second layer forms an outer surface of the garment.

4. The sound insulation structure of claim 1, further comprising a third layer configured to be sound diffusing, wherein the second layer is configured to be sound reflecting.

5. The sound insulation structure of claim 4, wherein the third layer forms an inner surface of the garment.

6. The sound insulation structure of claim 1, wherein the first layer and the second layer are configured to reduce average sound loudness by 0.5 to 1 sone in the frequency range of 4,000 Hz to 8,000 Hz in portions where the first layer and the second layer overlap.

7. The sound insulation structure of claim 1, wherein the sound insulation structure has a total thickness of less than 30 mm.

8. The sound insulation structure of claim 1, wherein the first layer is textured on at least one surface.

9. The sound insulation structure of claim 1, wherein the second layer is a coating.

10. The sound insulation structure of claim 1, wherein at least one of the first layer and the second layer are removable from the sound insulation structure.

11. The sound insulation structure of claim 1, wherein at least a portion of the sound insulation structure is configured to be part of a hood.

12. The sound insulation structure of claim 11, wherein the hood comprises a frontal tip, and wherein the frontal tip is configured to be disposed at a wearer's forehead.

13. The sound insulation structure of claim 11, wherein the hood is configured to enclose at least 220 of space around a wearer's head in a horizontal plane at a center of the wearer's head.

14. The sound insulation structure of claim 11, wherein the hood comprises a draw cord configured to tighten an opening of the hood.

15. The sound insulation structure of claim 11, wherein the hood comprises a flap removably attached to a side of an opening of the hood, and wherein the flap is configured to reduce an opening of the hood.

16. A garment comprising the sound insulation structure of claim 1.

17. The garment of claim 16, wherein the garment comprises a hood, and wherein the sound insulation structure is disposed at the hood.

18. The garment of claim 16, wherein the garment comprises a hat, a beanie, or a headband.

19. The garment of claim 16, wherein the sound insulation structure is removably attached to the garment.

20. A sound insulation structure for a wearable accessory, the sound insulation structure comprising: a first layer comprising a sound absorbing material; and a second layer attached to the first layer, the second layer configured to be at least one of sound reflecting and sound diffusing, wherein at least one of the first layer and the second layer are removable from the sound insulation structure, and wherein the sound insulation structure forms at least a part of the wearable accessory.

21. A method of manufacturing a sound insulation structure for a garment, the method comprising: providing a first layer comprising a sound absorbing material; providing a second layer configured to be at least one of sound reflecting and sound diffusing; molding the second layer such that the second layer is configured to diffuse sound; joining the first layer and the second layer; and forming at least a part of the garment with the first layer and the second layer.

22. The method of claim 21, further comprising: arranging the first layer and the second layer such that the first layer and the second layer at least partially overlap in the garment.

23. The method of claim 21, further comprising: providing a third layer configured to be sound diffusing; and joining the third layer and the first layer, wherein the second layer is configured to be sound reflecting.

24. The method of claim 21, further comprising: molding the sound absorbing material such that the sound absorbing material diffuses sound on at least one surface.

25. The method of claim 20, wherein at least one of the first layer and the second layer comprises a mesh.

26. The method of claim 21, wherein at least one of the first layer and the second layer comprises a mesh.

Description

BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES

(1) Aspects of the present invention will be explained in more detail with reference to the accompanying figures in the following. These figures show:

(2) FIG. 1 shows an exemplary embodiment of a sound insulation structure according to the invention arranged on a hooded garment with cut-away portions to reveal different layers;

(3) FIG. 2 shows a further exemplary embodiment of a sound insulation structure according to the invention arranged on a hooded garment;

(4) FIG. 3 shows an exemplary arrangement of a first and a second layer according to the invention in a cross-sectional schematic illustration;

(5) FIG. 4 shows an exemplary arrangement of a first, second, and third layer according to the invention in a cross-sectional schematic illustration;

(6) FIG. 5 shows a further exemplary arrangement of a first and a second layer according to the invention;

(7) FIG. 6 shows a cross-sectional schematic illustration of a sound insulation structure according to the invention;

(8) FIG. 7 shows a cross-sectional schematic illustration of a further exemplary arrangement of a first, second, and third layer according to the invention;

(9) FIG. 8 shows a schematic illustration of a sound insulation structure according to the invention using a spacer knit;

(10) FIG. 9 shows a cross-sectional schematic illustration of an exemplary three-dimensional arrangement of a first, second, and third layer according to the invention;

(11) FIG. 10 shows a cross-sectional schematic illustration of a further exemplary arrangement of a first and a second layer according to the invention being joined at the periphery; and

(12) FIG. 11 shows a cross-sectional schematic illustration of a further exemplary arrangement of a first, second, and third layer according to the invention, wherein the second layer is textured.

DETAILED DESCRIPTION OF THE INVENTION

(13) In the following, embodiments and variations of the present invention are described in more detail.

(14) FIG. 1 shows an exemplary embodiment of a sound insulation structure 10 for a garment 11. The garment 11 in the exemplary embodiment of FIG. 1 is a hooded garment like a tracksuit top. In general, the sound insulation structure 10 according to the invention may be used for a variety of garments including hats, caps, and beanies. The sound insulation structure 10 may alternatively or additionally be arranged around a pocket of a garment which reduces noise generated by coins, keys, etc. when the wearer of the garment walks, exercises, or runs, for example.

(15) In the exemplary embodiment of FIG. 1 the sound insulation structure 10 is arranged on the hood 12 of the garment 11. The sound insulation structure 10 comprises a first layer 13 comprising a sound absorbing material. In the exemplary embodiment of FIG. 1, the first layer 13 is a core layer of the hood 12. The first layer 13 comprises a sound absorbing material, i.e., the material of the first layer 13 is more sound absorbing than the material of the second layer 14 of the sound insulation structure 10 to be discussed below. The material of the first layer 13 may be a foam, a material comprising some partially-void cavities, a mesh, or a spacer knit fabric. In the latter case, the spacer knit fabric may be chosen to have good sound absorbing properties which may be achieved for example by an appropriate spacer yarn and/or by an appropriate knitting technique.

(16) In the embodiment of FIG. 1, the material of the first layer 13 is a polyurethane foam.

(17) The sound insulation structure 10 also comprises a second layer 14 of a sound reflecting material. The sound reflecting material of the second layer 14 is more sound reflecting than the material of the first layer 13.

(18) The material of the second layer 14 may, for example, be a coating coated onto the first layer 13.

(19) The second layer 14 of the sound insulation structure 10 according to the invention may be obtained by texturing the first layer's surface. Surface texturing may be achieved by providing the surface with a 3D shape. Surface texturing may improve the sound diffusion properties of the sound insulation structure. The textured second layer 14 may be covered by one or more layers. Thus, the textured second layer 14 may not be visible from the outside and/or inside. For example, the first layer 13 and second layer 14 may be sandwiched between two other layers. One of those latter layers may comprise a sound diffusing and/or reflecting layer. The surface texturing may be at an inner surface, an outer surface or both surfaces of the first layer 13. The surface texturing may have the shape of pyramids, hemispheres, cubes, etc. Surface texturing may also be provided by a knitted first layer 13. Thus, the knitted layer forms small holes, a relief of some depth and/or a certain pattern which increases sound diffusion.

(20) In the exemplary embodiment of FIG. 1, the second layer 14 is arranged as an outer layer of the hood 12 of the garment 11 and comprises a sound reflecting material. However, in other embodiments, the second layer 14 may comprise a sound diffusing material or a material being both sound reflecting and sound diffusing. Also, in other embodiments, the second layer 14 may be arranged as an inner layer of the hood 12, i.e., beneath the first layer 13 and may be sound reflecting, sound diffusing or both. This may also be advantageous, for example, in applications where the sound generated inside a garment or an accessory must be reduced, such as in a pocket or in a backpack.

(21) In the exemplary embodiment of FIG. 1, the material of the first layer 13 and the material of the second layer 14 are different materials. However, the material of the first layer 13 and the material of the second layer 14 may also be the same material. In this case, the material may have different properties in each layer. For example, the material in the first layer 13 may have a different density, fiber structure, shape, surface texture, etc. than the material in the second layer 14. Thus, in the first layer 13, the material may be more sound absorbing than in the second layer 14. On the other hand, the material in the second layer 14 may be more sound diffusing and/or reflecting than in the first layer 13.

(22) In general, all layers according to the invention may be either made from one piece or may be made from different pieces which may be overlapping or not. For example, two or more pieces of a layer (e.g., the sound absorbing layer 13) could overlap over the ears of a wearer to increase sound absorbance. It is also possible that the thickness of a layer varies. For example, a sound absorbing layer 13 could be thicker in the area of the ears of a wearer to increase sound absorbance in that area.

(23) In the exemplary embodiment of FIG. 1, the first layer 13 and the second layer 14 coincide in their entirety as they are arranged as layers of the hood 12. In other embodiments the first layer 13 may be separated from the second layer 14, i.e., both layers may be arranged at different locations on the garment 11. In further embodiments, the first layer 13 may at least partially overlap the second layer 14. Thus, different arrangements of the first layer 13 and the second layer 14 are possible which may be chosen depending on the type of application.

(24) In the exemplary embodiment of FIG. 1, the sound insulation structure further comprises a third layer 15 comprising a sound diffusing material. The material of the third layer 15 is understood to be more sound diffusing than the material of the first layer 13 and the material of the second layer 14. In the exemplary embodiment of FIG. 1 different materials were chosen for the first layer 13 and the third layer 15. However, in other embodiments, the same material could be used for the first layer 13 and the third layer 15 having different properties in each layer. For example, the material in the first layer 13 may have a different density, fiber structure, shape, surface texture, etc. than the material in the third layer 15. Thus, in the first layer 13, the material may be more sound absorbing than in the third layer 15. On the other hand, the material in the third layer 15 may be more sound diffusing than in the first layer 13. The third layer 15 may for example be a warp knitted layer. Furthermore, the material of the third layer 15 may be a coating on the first layer 13, a coating on the second layer 14, or a coating on a further layer of the garment 11.

(25) In the exemplary embodiment of FIG. 1, the sound diffusing inner layer 15 avoids or at least reduces the funnel effect described above by diffusing the impacting sound waves in all directions instead of focusing them onto the ears. Likewise, resonances may be reduced by the sound diffusing inner surface 15 of the hood 12.

(26) Measurements conducted on an exemplary embodiment similar to that of FIG. 1 have been led. In this embodiment, the hood comprises a first layer made of a PU foam with open cells, an inner layer made of a mesh with open holes, and an outer layer made of a mesh with open holes. The three layers were stitched together on the edges of the hood. The sound insulation structure forms the hood and has a total thickness of about 3 mm.

(27) For such measurements a mannequin head with a microphone placed on one of its ears has been placed in a room. In this room two speakers have been spaced apart by one meter and placed so as to form an equilateral triangle with the head of the mannequin. The measurements have been repeated with the mannequin looking between the two speakers (in a direction 30 degrees from each speaker, front in the table below), with the mannequin looking right from the speakers (in a direction 60 degrees from a first speaker and 120 degrees from the other, right in the table below), and with the mannequin looking away from the speakers (in a direction 150 degrees from each speaker, rear in the table below). A first series of measurements have been made with nothing on the mannequin's head, and a second series with said hood placed on the mannequin head.

(28) The results of these measurements are provided in tables 1 and 2 below.

(29) TABLE-US-00001 TABLE 1 Sound Magnitude Reduction Front Right Rear 1-4 kHz 4-8 kHz 1-4 kHz 4-8 kHz 1-4 kHz 4-8 kHz Average 5.0 8.3 5.5 13.3 5.0 7.7 Reduction [dB/20 Pa] Standard 3.4 3.1 4.0 5.1 2.8 2.6 Deviation [dB/20 Pa] Maximum 11.3 16.4 12.1 22.9 10.1 14.3 reduction [dB/20 Pa]

(30) Table 1 shows the average reduction in sound wave magnitude on the indicated frequency range, the standard deviation around this average for the set of measurements obtained, and the maximum value in each frequency range, for each incoming direction of the sound (front, right, back). The magnitude reduction is measured in decibels, with the reference sound pressure being 20 Pa.

(31) TABLE-US-00002 TABLE 2 Sound Loudness Reduction Front Right Rear 1-4 kHz 4-8 kHz 1-4 kHz 4-8 kHz 1-4 kHz 4-8 kHz Average 0.36 0.72 0.57 0.97 0.38 0.71 Reduction [sone] Standard 0.29 0.15 0.48 0.50 0.21 0.08 Deviation [sone] Maximum 0.86 0.98 0.80 1.62 0.73 0.79 reduction [sone]

(32) Table 2 shows the results of table 1 weighted by a human sensitivity to frequencies, the result being expressed in sones.

(33) It should be noted that these measurements reflect the properties of an exemplary embodiment of the present invention and are not to be understood as limiting.

(34) For example, the material of the first layer 13 and the material of the second layer 14 may be chosen so as to reduce average sound pressure by at least 6 dB, at least in the frequency range of 4,000 Hz to 20,000 Hz.

(35) In general, in the context of the present invention, the sound insulation structure 10 for a garment 11 may reduce average sound pressure by at least 6 dB, at least in the frequency range of 4,000 Hz to 20,000 Hz. The sound insulation structure 10 may reduce average sound pressure by at least 8 dB, more particularly by at least 10 dB, and in some embodiments by at least 16 dB at least in the frequency range of 4,000 Hz to 20,000 Hz. The sound insulation structure 10 may reduce average sound pressure by at least 6 dB, in particular by at least 10 dB, and in some embodiments by at least 15 dB in the human ear range of 20 Hz to 20,000 Hz. The sound insulation structure 10 may reduce the sound perceived by a wearer of the garment 11 by at least one sone, more particularly by at least two sones. The sound insulation structure 10 may reduce average sound pressure and/or sound perceived by a wearer of the garment 11 for sound waves impacting the sound insulation structure 10 perpendicular to a surface of the sound insulation structure 10.

(36) In general, in the context of the present invention, the sound insulation structure 10 for a garment 11 may have a total thickness of less than 30 mm. The total thickness may be less than 20 mm, in particular less than 10 mm, and in some embodiments less than 5 mm, e.g., about 3 mm. This is in particular true for a sound insulation structure with damping characteristics according to tables 1 and 2 above.

(37) Furthermore, the sound insulation structure 10 for a garment 11 may reduce average sound pressure by at least 6 dB, at least in the frequency range of 4,000 Hz to 20,000 Hz and may comprise a total thickness of less than 30 mm, in particular less than 20 mm, in particular less than 10 mm, and in some embodiments less than 5 mm, e.g., about 3 mm. The sound insulation structure 10 comprising a total thickness of less than 30 mm, in particular less than 20 mm, in particular less than 10 mm, and in some embodiments less than 5 mm, e.g., about 3 mm, may reduce average sound pressure by at least 8 dB, more particularly by at least 10 dB and in some embodiments by at least 16 dB, at least in the frequency range of 4,000 Hz to 20,000 Hz. The sound insulation structure 10 comprising a total thickness of less than 30 mm, in particular less than 20 mm, in particular less than 10 mm, and in some embodiments less than 5 mm, e.g., about 3 mm, may reduce average sound pressure by at least 6 dB, in particular by at least 10 dB, and in some embodiments by at least 15 dB in the human ear range of 20 Hz to 20,000 Hz. The sound insulation structure 10 comprising a total thickness of less than 30 mm, in particular less than 20 mm, in particular less than 10 mm, and in some embodiments less than 5 mm, e.g., about 3 mm, may reduce the sound perceived by a wearer of the garment 11 by at least one sone, more particularly by at least two sones. The sound insulation structure 10 comprising a total thickness of less than 30 mm, in particular less than 20 mm, in particular less than 10 mm, and in some embodiments less than 5 mm, e.g., about 3 mm, may reduce average sound pressure and/or sound perceived by a wearer of the garment 11 for sound waves impacting the sound insulation structure 10 perpendicular to a surface of the sound insulation structure 10.

(38) In the exemplary embodiment of FIG. 1, the first layer 13, the second layer 14, and the third layer 15 are permanently attached to each other and form, together, the sound insulation structure 10 which coincides with the garment's hood. The layers are stitched together at the edges of the hood by a merrow (or overlock) stitch. In general, however, different stitches or different joining techniques such as gluing or welding could be used as well.

(39) However, in other embodiments, the first layer 13 or the second layer 14 or both may be removable from the sound insulation structure. The same is true for the third layer 15. Thus, at least one layer may be removably attached to the sound insulation structure 10. In one embodiment, the whole sound insulation structure 10 may be removably attached to the garment 11. Means for removably attaching the layers and/or the sound insulation structure may be a hook-and-loop fastener, a zipper, a press-stud, or the like.

(40) In some embodiments, the first layer 13 and/or the second layer 14 and/or the third layer 15 (if present) may comprise perforations. In this way, breathability of the sound insulation structure and, thus, of the garment may be improved. Such perforations may, for example, be created by loops of a weft or warp knit fabric, by the apertures of a mesh, or may be punched out.

(41) In the exemplary embodiment of FIG. 1, the hood 12 may be configured so that the distance between the hood 12 and an ear of a wearer is at maximum 20 cm. In some embodiments, the distance is less than 80 mm and more particularly between 10 mm and 40 mm. In some embodiments including, for example, the hooded garment 11 of FIG. 1, but also hats, beanies, headbands, and caps, the garment 11 may be fit on the ear of the wearer, thereby reducing the distance to 0 mm. The garment 11 may be stretchable so that the garment 11 tightly fits the wearer's head. At least a layer of said garment may be stretchable to tightly fit the wearer's head.

(42) The hood 12 may be configured so that the frontal tip of the hood comes to the forehead of the wearer. The hood 12 may further be configured so that the frontal tip of the hood comes to the forehead of a wearer when the head of the wearer touches the back of the hood 12. In other embodiments, the hood comes down to the eyebrows. In further embodiments, the hood's tip may come down lower than the eyebrows (e.g., to the nose) in order to further reduce the incoming noise.

(43) The hood 12 may be configured to enclose at least 220 of the space around a wearer's head, in particular at least 260, and more particularly at least 275. The covering angle of the hood 12 may be defined from the center of the wearer's head and may be defined in a cross sectional plane perpendicular to the wearer's longitudinal axis (i.e., a transverse plane in an anatomical meaning or horizontal plane).

(44) The hood 12 may comprise means to tighten the opening of the hood. This permits lowering the sound entering from the front opening of the hood. The tightening means may be a draw cord. The cord may be arranged in a tunnel, e.g., sewn on the edge of the hood's opening.

(45) The hood 12 may comprise a flap configured to be removably attached to the other side of an opening of the hood 12 so as to reduce the diameter of the opening of the hood 12. The flap may be attached to the hood 12 by means of a hook-and-loop fastener, a press-stud, a magnet, or the like. The flap may be arranged in the bottom of the hood 12 so as to close the opening in front of the neck of a wearer. In some embodiments, the flap may be configured to close the opening in front of a chin of a wearer.

(46) FIG. 2 shows a further embodiment of a sound insulation structure 10 arranged on a hood 12 of a garment 11. In the exemplary embodiment of FIG. 2, the sound insulation structure 10 comprises a first layer 13 being the core layer of the hood 12, i.e., the first layer 13 defines the shape of the hood 12. The core layer is made from a sound absorbing material. The sound absorbing material is a PU foam with open cells.

(47) As in FIGS. 6 and 7, the sound absorbing material forms the core layer which is sound absorbing and an inner layer (i.e., the side of the hood 12 facing the head of the wearer) which is sound diffusing and sound absorbing. The inner layer 15 is sound absorbing because it is made of the same sound absorbing material as the core layer 13, and it is sound diffusing because it comprises a textured surface, for example a pyramid-shaped surface structure as in FIG. 7. Such a pyramid-shaped surface structure helps to diffuse incoming sound waves. The inner layer 15 is joined to the core layer 13 by stitching both layers at their respective edges. However, the layers may be joined at other locations additionally or alternatively. Furthermore, other techniques like welding or gluing could be used as well.

(48) In this embodiment, the core layer 13 and inner layer 15 may be manufactured by a hot or cold forming process. To this end, foamed material is placed in a mold comprising a surface structure corresponding to the negative of the surface structure of the inner layer 15. Then, the material of the core layer 13 and inner layer 15 is pressed under pressure. The resulting material layers are cut to shape and an outer layer of the hood 12 may be joined to it by sewing, gluing, or welding, or be sprayed on it. An additional inner layer may be added onto the inner layer 15 to improve its sound diffusing properties and/or to improve the comfort of the wearer. In one embodiment, this inner layer may be acoustically transparent.

(49) FIG. 3 shows an exemplary arrangement of a first layer 13 and a second layer 14 according to the invention. The first layer 13 in this example is sound absorbing, whereas the second layer 14 is either sound diffusing, sound reflecting, or both. The second layer 14 in this example is bonded to the first layer 13, for example, by gluing. The second layer 14 may be arranged on an outer surface of the first layer 13 to reflect or diffuse ambient noise. In an alternative embodiment, the second layer 14 may be arranged on an inner surface of the first layer 13 to help reduce the sound generated inside a garment or bag. For example, the garment may comprise a pocket formed by a sound absorbing core layer 13 and lined on its inner surface by a sound reflecting or diffusing layer 14. Thus, sound generated by objects carried in the pocket (e.g., coins) is significantly reduced by such an arrangement. Consequently, such an arrangement could be used with a bag, like a backpack, sports bag, etc., as well.

(50) FIG. 4 shows a further exemplary arrangement of a sound absorbing first layer 13, a sound reflecting second layer 14, and a sound diffusing third layer 15. The second layer 14 and the third layer 15 in this example are bonded to the first layer 13, for example, by gluing. The second layer 14 could be arranged on an outer surface of a garment and the third layer 15 could be arranged on an inner surface of a garment. Such an arrangement could be advantageous, for example, with a hooded garment, where the sound insulation structure 10 formed by the three layers 13, 14, and 15 is arranged on the hood or forms at least a part of the hood. In this example, the second layer 14 would reflect ambient noise, whereas the third layer 15 would diffuse ambient noise entering the hood through its opening, thus decreasing the funnel effect described above. It should be noted, however, that in other embodiments the arrangement of the second layer 14 and third layer 15 could be reversed, i.e., the second layer 14 could be arranged on an inner surface of the first layer 13 and the third layer 15 could be arranged on an outer surface of the first layer 13.

(51) FIG. 5 shows a further exemplary embodiment of a sound absorbing first layer 13 and a second layer 14 according to the invention. In this example, the second layer 14 is sound diffusing. Additionally, the second layer 14 comprises holes, three of which are exemplarily denoted with the reference numeral 51. The second layer 14 may be a mesh, for example a knit polyester mesh

(52) The first layer 13 and second layer 14 are arranged, such that there is a gap between both layers. This is achieved by a yarn 52 which interconnects both layers 13 and 14. However, the yarn 52 does not join both layers 13 and 14, such that they would abut, like with a stitch. Instead, the yarn 52 allows for a spaced apart arrangement of both layers 13 and 14. This joining of the first layer 13 and second layer 14 may provide, in particular, a better comfort for the wearer.

(53) FIG. 6 shows a cross sectional view of a further exemplary embodiment of a sound insulation structure 10 according to the invention. In this example, the sound insulation structure is made from a single material. The material comprises a density gradient in a direction perpendicular to a surface of the sound insulation structure 10. The material has a higher density on its outer surface 62 than in other portions, thereby creating a sound reflecting layer 14. Thus, the sound reflecting layer 14 is formed by high density material. Such density may be reached by different manufacturing processes, such as use of gravity during manufacturing to separate two layers, or curing (e.g., by heat), etc.

(54) From this sound reflecting layer 14 the density decreases and a continuous layer of material forms the sound absorbing layer 13.

(55) A sound diffusing layer 15 is created on the inner face of the sound insulation structure 10 by a surface texturing of the material. In the example of FIG. 6, this surface structure is formed by a random sequence of grooves, three of which are exemplarily denoted by the reference numeral 61. Other surface texturing could be used as well, such as pyramids, hemispheres, cubes, etc. which could be regular or random. In addition to facilitating sound diffusion, surface texturing also increases the flexibility and pliability of the sound insulation structure 10. The surface texturing can be formed during manufacturing the sound insulation structure 10, e.g., during molding, or could be formed in a later step, e.g., by cutting, milling, melting, etc.

(56) FIG. 7 shows a further exemplary arrangement of the first layer 13, second layer 14, and third layer 15. In this example, the sound reflecting second layer 14 is bonded to the first sound absorbing layer 13, e.g., by gluing. The sound diffusing third layer 15 is made from the same material as the first sound absorbing layer 13 and formed in this material as a textured area. The texture in this example is pyramid-shaped. In general, other geometries like random or regular hemispheres, cones, cubes, ridges, etc. could be used as well.

(57) FIG. 8 shows a further exemplary arrangement of a first layer 13 and a second layer 14 according to the invention. In this example the first sound absorbing layer 13 is realized as a spacer knit. A spacer knit is manufactured by weft-knitting or warp-knitting at least one spacer yarn 81 between two weft-knitted or warp-knitted plies 82 and 83, interconnecting the two plies 82 and 83 while leaving a gap between these two plies, and simultaneously serving as a filler. The spacer yarn 81 can comprise the same material as the plies 82 and 83 themselves, e.g., polyester, or another material. The spacer yarn 81 can also be a monofilament which provides the spacer weft-knitted fabric or spacer warp-knitted fabric with more stability. In the exemplary embodiment of FIG. 8 the second layer 14 is coated on a ply 83 of the spacer knit. Such a coating may, for example, be provided by spray coating. The gap between the two plies 82 and 83 of the spacer knit allows for additional frequency-selective noise cancellation, because the gap acts like a resonant filter for sound waves entering the spacer knit. Thus, the frequency response of the sound absorbing layer 13 can be set by varying the distance of the two plies 82 and 83 correspondingly.

(58) FIG. 9 shows a further exemplary arrangement of the first layer 13, second layer 14, and third layer 15. In this example, all three layers comprise a 3D shape in the form of a zig-zag shape. In general, different shapes could be used as well, such as a sinusoidal or rectangular shape. Such a 3D shape further increases sound diffusion on both faces of the sound insulation structure 10, but also increases flexibility and pliability of the whole sound insulation structure 10.

(59) FIG. 10 shows a further exemplary arrangement of the first sound absorbing layer 13 and the second sound reflecting or diffusing layer 14. In this example, the first layer 13 and the second layer 14 are only joined along their periphery. Thus, in other locations the first layer 13 and the second layer 14 are allowed to be spaced apart. The gap between the first layer 13 and the second layer 14 could be filled for example by down, foam, or another filler material to increase thermal insulation. In the example of FIG. 10, both layers are joined by a seam 101 which can be sewn either by hand or by a sewing machine. In general, however, other techniques like welding or gluing could be used as well.

(60) FIG. 11 shows a further exemplary embodiment of a sound insulation structure 10 according to the invention, wherein the second layer 14 is shaped with plies, but not the first layer 13. In the example, the second layer 14 comprises a triangular or pyramid shape and is spaced apart from the first layer 13. The shape of the second layer 14 can be obtained by folding the second layer 14 appropriately. Other shapes could be used as well, such as hemispheres, cones, cubes, ridges, etc. In this example, the shaped second layer 14 could be an inner layer or an outer layer of a garment.

(61) In some embodiments, at least one layer may be obtained by a melt-blown process. In a melt-blown process, molten filaments emerge from a spinneret, are drawn by a primary air flow, and are broken into staple fibers by eddy currents. A secondary air flow transfers the fibers onto a substrate. Melt blowing is a very efficient process for producing non-woven fabrics. The layer may be obtained by blowing fibers onto a substrate.

(62) More particularly, the first sound-absorbing layer may be obtained by a melt-blown process. In particular, the size and density of the fibers may be chosen to obtain a high sound absorption in a targeted range of frequencies.

(63) The second layer may be obtained by a post-processing of one face of the non-woven first layer, for example by application of heat and/or pressure. The second layer may also be obtained by applying heat and/or pressure to a non-woven fabric, which is then combined with the first layer.

(64) The substrate may be a three-dimensional shape. Thereby, the non-woven layer may be directly formed in a three-dimensional shape of the final product. Thus, no additional forming of the non-woven fabric is required as it is directly made to its useful shape. The three-dimensional shape may, for example, be a shape of a head, a hood, a pocket, etc.

(65) The substrate may have a texture. The non-woven layer thereby adopts a negative texture on its face in contact with the substrate. Such texture may enhance comfort and/or sound diffusion.

(66) The substrate may comprise a plurality of holes in at least a portion of its surface and the method may further comprise the step of applying a pressure differential to the plurality of holes, so that the fibers transferred onto the substrate are attracted by the pressure differential. This allows compacting the fibers together to obtain a more dense non-woven fabric. In some embodiments, it may also allow creating a texture on the surface so as to improve its sound diffusion, sound absorption, and/or comfort, in particular with a wide array in which the fibers are pulled in the holes of the array so as to form padded humps on the surface of the non-woven fabric.

(67) The present invention has been described above by way of exemplary embodiments. Accordingly, the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalences. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.