Acoustic signal output device

Abstract

To provide a sound signal output device that does not hermetically seal an external acoustic meatus and can suppress sound leakage to the surroundings.SOLUTION: There is provided a sound signal output device 20 having a structure portion including a single or a plurality of sound holes 121a that emit sound signals AC1 to the outside, a hollow portion 220 having an inner space into which sound signals AC2 are emitted, and a single or a plurality of sound holes 123a that emit the sound signals AC2 emitted to the inner space of the hollow portion 220 to the outside. Here, the sound signal output device is designed so that the resonance frequency of the hollow portion 220 is equal to or higher than a predetermined frequency, and the sound signal AC2 in which frequency band components including the predetermined frequency are suppressed is emitted to the outside from the sound holes 123a.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] The present invention relates to an acoustic signal output device, and more particularly to an acoustic signal output device that does not seal the ear canal. [Background technology]

[0002] In recent years, the increased strain on the ears caused by wearing earphones and headphones has become a problem. Open-ear earphones and headphones, which do not block the ear canal, are known as devices that reduce the strain on the ears. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] “WHAT ARE OPEN-EAR HEADPHONES?”, [online], Bose Corporation, [Retrieved May 16, 2022], Internet<https: / / www.bose.com / en_us / better_with_bose / open-ear-headphones.html> [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] However, open-ear earphones and headphones have the problem of significant sound leakage to the surroundings. This problem is not limited to open-ear earphones and headphones, but is a common issue with any acoustic signal output device that does not seal the ear canal.

[0005] This invention has been made in view of these points, and aims to provide an acoustic signal output device that does not seal the ear canal and can suppress sound leakage to the surroundings. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention provides an acoustic signal output device having a structure comprising: one or more first sound holes for emitting a first acoustic signal to the outside; a hollow section for emitting a second acoustic signal into an internal space; and one or more second sound holes for emitting the second acoustic signal emitted into the internal space of the hollow section to the outside. Here, the hollow section is designed so that its resonant frequency is above a predetermined frequency, and the second acoustic signal, in which frequency band components including the predetermined frequency are suppressed, is emitted to the outside from the second sound holes. [Effects of the Invention]

[0007] This allows for the suppression of sound leakage to the surroundings without sealing the ear canal. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a perspective view illustrating the configuration of an acoustic signal output device according to an embodiment. [Figure 2] Figure 2A is a transparent plan view illustrating the configuration of the acoustic signal output device according to the embodiment. Figure 2B is a transparent front view illustrating the configuration of the acoustic signal output device according to the embodiment. [Figure 3] Figure 3A is an end view of 2BA-2BA in Figure 2B. Figure 3B is an end view of 2A-2A in Figure 2A. [Figure 4] Figures 4A and 4B are conceptual diagrams illustrating the arrangement of tone holes. [Figure 5] Figure 5 is a diagram illustrating the usage state of the acoustic signal output device according to the embodiment. [Figure 6] Figure 6A is a diagram illustrating the usage state of the acoustic signal output device of the embodiment. Figure 6B is a diagram illustrating the observation conditions of the acoustic signal emitted from the acoustic signal output device of the embodiment. [Figure 7] Figure 7 illustrates how the acoustic signal output device of the embodiment is placed on a flat surface. [Figure 8]FIG. 8A is a front view for illustrating the arrangement of sound holes. FIGS. 8B and 8C are front views for illustrating the arrangement of sound holes. [Figure 9] FIGS. 9A and 9B are conceptual diagrams for illustrating the arrangement of sound holes. [Figure 10] FIGS. 10A and 10B are conceptual diagrams for illustrating the arrangement of sound holes. [Figure 11] FIG. 11A is a 2BA-2BA end view of FIG. 2B. FIG. 11B is a 2A-2A end view of FIG. 2A. [Figure 12] FIG. 12A is a 2BA-2BA end view of FIG. 2B. FIG. 12B is a conceptual diagram illustrating the drive system of the acoustic signal output device of the embodiment. [Figure 13] FIG. 13 is a graph illustrating an equal-loudness curve (ISO 226:2003 Acoustics - Normal equal-loudness-level contours). [Figure 14] FIG. 14A is a graph for illustrating the relationship between the volume of the internal space of the housing and the resonance frequency. FIG. 14B is a graph for illustrating the sound pressure levels in the case of using an LPF (with LPF) and the case of not using an LPF (without LPF). [Figure 15] FIG. 15 is a diagram for illustrating a configuration for attaching the acoustic signal output device of the embodiment to the auricle. [Figure 16] FIG. 16 is a diagram for illustrating a configuration provided on the temple of glasses for the acoustic signal output device of the embodiment. FIG. 16A is a front view of the acoustic signal output device of the embodiment. FIG. 16B is a magnified transparent view of FIG. 16A. FIG. 16C is a magnified rear view of the acoustic signal output device of the embodiment. [Figure 17] FIG. 17 is a front view for illustrating a modified example of the acoustic signal output device of the embodiment. Embodiment [Figure 18] FIG. 18A is a perspective view for illustrating a modified example of the acoustic signal output device of the embodiment. FIG. 18B is a plan view for illustrating a modified example of the acoustic signal output device of the embodiment. [Figure 19]Figure 19 is a plan view illustrating a modified example of the acoustic signal output device of the embodiment. [Figure 20] Figure 20A is a plan view illustrating a modified example of the acoustic signal output device of the embodiment. Figure 20B is a right side view illustrating a modified example of the acoustic signal output device of the embodiment. Figure 20C is a front view illustrating a modified example of the acoustic signal output device of the embodiment. Figure 20D is a rear view illustrating a modified example of the acoustic signal output device of the embodiment. Figure 20E is a front view illustrating the usage state of the modified acoustic signal output device of the embodiment. [Figure 21] Figure 21A is a perspective view illustrating a modified example of the acoustic signal output device of the embodiment. Figure 21B is a perspective view illustrating a modified example of the acoustic signal output device of the embodiment. Figure 21C is a perspective view illustrating the usage state of the modified acoustic signal output device of the embodiment. [Figure 22] Figure 22A is a front view illustrating a modified example of the acoustic signal output device of the embodiment. Figure 22B is a rear view illustrating a modified example of the acoustic signal output device of the embodiment. [Figure 23] Figure 23A is a front view illustrating a modified example of the acoustic signal output device of the embodiment. Figure 23B is a rear view illustrating a modified example of the acoustic signal output device of the embodiment. Figure 23C is a front view illustrating the usage state of the modified acoustic signal output device of the embodiment. [Figure 24] Figure 24A is a plan view illustrating a modified example of the acoustic signal output device of the embodiment. Figure 24B is a right side view illustrating a modified example of the acoustic signal output device of the embodiment. Figure 24C is a front view illustrating a modified example of the acoustic signal output device of the embodiment. Figure 24D is a rear view illustrating a modified example of the acoustic signal output device of the embodiment. Figure 24E is a front view illustrating the usage state of the modified acoustic signal output device of the embodiment. [Figure 25]Figure 25A is a plan view illustrating a modified example of the acoustic signal output device of the embodiment. Figure 25B is a front view illustrating a modified example of the acoustic signal output device of the embodiment. Figure 25C is a rear view illustrating a modified example of the acoustic signal output device of the embodiment. Figure 25D is a front view illustrating the usage state of the modified acoustic signal output device of the embodiment. [Figure 26] Figure 26A is a plan view illustrating a modified example of the acoustic signal output device of the embodiment. Figure 26B is a front view illustrating a modified example of the acoustic signal output device of the embodiment. Figure 26C is a rear view illustrating a modified example of the acoustic signal output device of the embodiment. Figure 26D is a front view illustrating the usage state of the modified acoustic signal output device of the embodiment. [Figure 27] Figure 27A is a left side view illustrating a modified example of the acoustic signal output device of the embodiment. Figure 27B is a front view illustrating a modified example of the acoustic signal output device of the embodiment. Figure 27C is a front view illustrating the usage state of the modified acoustic signal output device of the embodiment. [Figure 28] Figure 28A is a plan view illustrating a modified example of the acoustic signal output device of the embodiment. Figure 28B is a right side view illustrating a modified example of the acoustic signal output device of the embodiment. Figure 28C is a front view illustrating a modified example of the acoustic signal output device of the embodiment. Figure 28D is a rear view illustrating a modified example of the acoustic signal output device of the embodiment. Figure 28E is a front view illustrating the usage state of the modified acoustic signal output device of the embodiment. [Figure 29] Figure 29A is a conceptual diagram illustrating a modified example of the acoustic signal output device of the embodiment. Figure 29B is a perspective view illustrating a modified example of the acoustic signal output device of the embodiment. [Figure 30] Figure 30A is a front view illustrating a modified example of the acoustic signal output device of the embodiment. Figure 30B is a left side view illustrating a modified example of the acoustic signal output device of the embodiment. Figure 30C is a right side view illustrating a modified example of the acoustic signal output device of the embodiment. [Figure 31]Figure 31A is a front view illustrating a modified example of the acoustic signal output device of the embodiment. Figure 31B is a left side view illustrating a modified example of the acoustic signal output device of the embodiment. Figure 31C is a right side view illustrating a modified example of the acoustic signal output device of the embodiment. [Figure 32] Figure 32A is a front view illustrating a modified example of the acoustic signal output device of the embodiment. Figure 32B is a rear view illustrating a modified example of the acoustic signal output device of the embodiment. [Figure 33] Figure 33 is a conceptual diagram illustrating a modified example of the acoustic signal output device of the embodiment. [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described below with reference to the drawings. [First Embodiment] The acoustic signal output device 10 of this embodiment is an acoustic listening device (for example, open-ear type earphones, headphones, etc.) that is worn without sealing the user's ear canal. As illustrated in Figures 1, 2A, 2B, 3A, and 3B, the acoustic signal output device 10 of this embodiment includes a driver unit 11 that converts an output signal (an electrical signal representing an acoustic signal) output from a playback device into an acoustic signal and outputs it, a housing 12 (structural part) that houses the driver unit 11 inside, and a support part 13 (structural part) that is positioned on the user's auricle when worn.

[0010] <Driver Unit 11> The driver unit (speaker driver unit) 11 is a device (a device with speaker functionality) that emits an acoustic signal AC1 (first acoustic signal) based on the input output signal to one side (direction D1), and emits an acoustic signal AC2 (second acoustic signal), which is the inverse phase signal (phase inversion signal) of the acoustic signal AC1 or an approximate signal of the inverse phase signal, to the other side (direction D2). That is, the acoustic signal emitted from the driver unit 11 to one side (direction D1) will be called the acoustic signal AC1 (first acoustic signal), and the acoustic signal emitted from the driver unit 11 to the other side (direction D2) will be called the acoustic signal AC2 (second acoustic signal). The acoustic signal AC1 is used for the user to hear the sound, and the acoustic signal AC2 is used to suppress sound leakage to the surroundings. For example, the driver unit 11 includes a diaphragm 113 that, through vibration, emits an acoustic signal AC1 from one surface 113a toward the D1 direction, and through this vibration, emits an acoustic signal AC2 from the other surface 113b toward the D2 direction (Figure 2B). In this example, the driver unit 11 vibrates the diaphragm 113 based on the input output signal, emitting the acoustic signal AC1 from one surface 111 toward the D1 direction, and emitting an acoustic signal AC2, which is the inverse phase signal of the acoustic signal AC1 or an approximate signal of the inverse phase signal, from the other side 112 toward the D2 direction. In other words, the acoustic signal AC2 is emitted secondarily along with the emission of the acoustic signal AC1. Note that the D2 direction (the other side) is, for example, the opposite direction of the D1 direction (one side), but the D2 direction does not need to be strictly the opposite direction of the D1 direction; it is sufficient that the D2 direction is different from the D1 direction. The relationship between one side (direction D1) and the other side (direction D2) depends on the type and shape of the driver unit 11. Depending on the type and shape of the driver unit 11, the acoustic signal AC2 may be exactly the inverse phase signal of the acoustic signal AC1, or it may be an approximate signal of the inverse phase signal of the acoustic signal AC1. For example, the approximate signal of the inverse phase signal of the acoustic signal AC1 may be (1) a signal obtained by shifting the phase of the inverse phase signal of the acoustic signal AC1, (2) a signal obtained by changing (amplifying or attenuating) the amplitude of the inverse phase signal of the acoustic signal AC1, or (3) a signal obtained by shifting the phase of the inverse phase signal of the acoustic signal AC1 and further changing its amplitude.The phase difference between the out-of-phase signal of acoustic signal AC1 and its approximate signal should preferably be δ1 (rad) or less. Examples of δ1 include π / 36, π / 12, π / 6, π / 3, etc. Furthermore, the ratio of the amplitude of the approximate signal to the amplitude of the out-of-phase signal of acoustic signal AC1 should preferably be δ2 or less. Examples of δ2 include 0.1, 0.5, 1.0, 2.0, etc. For example, the amplitude of the sum signal obtained by adding acoustic signals AC1 and AC2 emitted from the driver unit 11 should be smaller than the amplitude of acoustic signal AC1. For example, let Ae^jωt be the sine wave of each frequency contained in acoustic signal AC1 emitted from the driver unit 11, and let δ2Ae^j(-ωt+δ1) be the sine wave of each frequency contained in acoustic signal AC2 emitted from the driver unit 11. Here, t represents time, ω represents angular frequency, A (A>0) represents amplitude, j represents the imaginary unit, and e represents Napier's number. Also, δ1 represents the phase difference (rad) between the out-of-phase signal of acoustic signal AC1 and acoustic signal AC2, and δ2 (δ2>0) represents the amplitude ratio between the out-of-phase signal of acoustic signal AC1 and acoustic signal AC2. The sum signal obtained by adding the two signals is as follows. (Ae^jωt)+{δ2Ae^j(-ωt+δ1)}=(1-δ2e^jδ1)Ae^jωt The absolute value of the amplitude of this sum signal is |(1-δ2e^jδ1)A|. Therefore, in order to make the amplitude of the sum signal smaller than the amplitude of the acoustic signal AC1, it is necessary to set |(1-δ2e^jδ1)| < 1. That is, the following must be satisfied.

number

[0011] <Enclosure 12> The housing 12 is a hollow member with an outer wall and houses the driver unit 11 inside. For example, the driver unit 11 is fixed to the end of the housing 12 on the D1 direction side. However, this does not limit the present invention. The shape of the housing 12 is also not limited, but for example, the shape of the housing 12 may be rotationally symmetric (line symmetric) or substantially rotationally symmetric about an axis A1 extending along the D1 direction. Note that axis A1 is an axis that extends in the D1 direction through the central region of the housing 12. For example, the housing 12 has a wall 121 located on one side (D1 direction side) of the driver unit 11, a wall 122 located on the other side (D2 direction side) of the driver unit 11, and a wall 123 (side) that surrounds the space between the wall 121 and the wall 122 about the axis A1 passing through the wall 121 and the wall 122 (Figures 2B, 3B). In this embodiment, for the sake of simplicity, an example is shown in which the housing 12 has a substantially cylindrical shape with faces at both ends. However, these are merely examples and do not limit the present invention. For example, the housing 12 may have a substantially dome shape with walls at its ends, a hollow substantially cubic shape, or any other three-dimensional shape. Furthermore, there are no limitations on the material that constitutes the housing 12. The housing 12 may be made of a rigid material such as synthetic resin or metal, or it may be made of an elastic material such as rubber.

[0012] <Sound holes 121a, 123a> The wall of the housing 12 is provided with a sound hole 121a (first sound hole) for releasing (leading out) the acoustic signal AC1 (first acoustic signal) emitted from the driver unit 11 to the outside, and a sound hole 123a (second sound hole) for releasing (leading out) the acoustic signal AC2 (second acoustic signal) emitted from the driver unit 11 to the outside. The sound holes 121a and 123a are, for example, through holes that penetrate the wall of the housing 12, but this is not a limitation of the present invention. The sound holes 121a and 123a do not have to be through holes, as long as the acoustic signals AC1 and AC2 can be released to the outside, respectively.

[0013] In this embodiment, the sound hole 121a (first sound hole) is provided in region AR1 (first region) of the wall portion 121 located on one side of the driver unit 11 (the side in the D1 direction from which the acoustic signal AC1 is emitted) (Figures 2B and 3B). In this embodiment, the sound hole 121a is positioned eccentrically, offset from axis A1 (central axis of the structural portion) in the B1 direction (first direction), and opens facing the D1 direction. The B1 direction is a specific radiation direction centered on axis A1. In this embodiment, for the sake of simplicity, an example is shown in which the shape of the edge of the open end of the sound hole 121a is elliptical (the open end is elliptical). However, this does not limit the present invention. For example, the shape of the edge of the sound hole 121a may be a circle, square, triangle, or other shape. Also, the end of the sound hole 121a may be mesh-like. In other words, the end of the sound hole 121a may be composed of multiple holes. Furthermore, in this embodiment, for the sake of simplicity, an example is shown in which one sound hole 121a is provided in region AR1 (first region) of the wall portion 121 of the housing 12. However, this does not limit the present invention. For example, two or more sound holes 121a may be provided in region AR1 (first region) of the wall portion 121 of the housing 12.

[0014] In this embodiment, the sound hole 123a (second sound hole) is provided in region AR3 of wall 123, which is in contact with region AR between region AR1 of wall 121 of housing 12 and region AR2 of wall 122 located on the D2 direction side of the driver unit 11 (the other side from which the acoustic signal AC2 is emitted). That is, if we take the center of housing 12 as the reference point and define the direction between the D1 direction and the opposite direction of the D1 direction as the D12 direction (Figure 3B), then the sound hole 123a (second sound hole) is provided on the D12 direction side of housing 12. For example, if the housing 12 has a wall portion 121 located on one side (D1 direction side) of the driver unit 11, a wall portion 122 located on the other side (D2 direction side) of the driver unit 11, and a wall portion 123 (side) that surrounds the space between the wall portions 121 and 122 around an axis A1 along the emission direction (D1 direction) of the acoustic signal AC1 passing through the wall portions 121 and 122 (Figures 2B, 3B), then the sound hole 123a (second sound hole) is provided on the wall portion 123 (side).

[0015] Furthermore, the tone hole 123a (second tone hole) in this embodiment is positioned biased toward the B2 direction (second direction). The B2 direction (second direction) is a direction that includes the opposite component of the B1 direction (first direction). For example, the tone hole 123a (second tone hole) is not provided on the B1 direction (first direction) side of axis A1. As illustrated in Figures 4A and 4B, when the tone hole 123a (second tone hole) is positioned in this way, the total area of ​​the opening end of the tone hole 123a (second tone hole) facing space SP1 (first space) is smaller than the total area of ​​the opening end of the tone hole 123a (second tone hole) facing space SP2 (second space). As a result, the sound pressure level of the acoustic signal AC2 (second acoustic signal) emitted from the sound hole 123a (second sound hole) into space SP1 (first space) is lower than the sound pressure level of the acoustic signal AC2 (second acoustic signal) emitted from the sound hole 123a (second sound hole) into space SP2 (second space). Space SP1 (first space) is the space located in the B1 direction (first direction) relative to the sound hole 121a (first sound hole), and space SP2 (second space) is the space located in the B2 direction (second direction) relative to the sound hole 121a (first sound hole). In other words, it is preferable to design the sound hole 123a to be positioned such that there are more sound holes 123a positioned further away from the sound hole 121a on the housing 12, and fewer sound holes 123a positioned closer to the sound hole 121a on the housing 12.

[0016] Furthermore, it is preferable not to provide sound holes on the wall portion 122 side of the housing 12. This is because if sound holes are provided on the wall portion 122 side of the housing 12, the sound pressure level of the acoustic signal AC2 emitted from the housing 12 will exceed the level necessary to cancel out the sound leakage component of the acoustic signal AC1, and this excess will be perceived as sound leakage.

[0017] <Support Department 13> As illustrated in Figures 1, 2B, and 3B, the support portion 13 is a convex-shaped portion provided on the outer surface of the wall portion 121 on the D1 direction side of the housing 12. The support portion 13 is provided with an open end 131b of the sound hole 121a, and the acoustic signal AC1 emitted from the sound hole 121a is emitted to the outside through the open end 131b. For example, the open end 131b is a through hole, which emits the acoustic signal AC1 emitted from the sound hole 121a to the outside.

[0018] At least a portion of the outer surface region 130 of the support portion 13 is convex. The outer surface region 130 is the outer surface region surrounding the opening end 131b of the sound hole 121a (first sound hole), and is, for example, an annular region located on the outer surface side of the support portion 13 in the D1 direction. The outer surface region 130 includes region 131 (first region) and region 132 (second region) which protrudes more than region 131 (first region), and is configured in a shape that guides the acoustic signal AC1 (first acoustic signal) emitted from the sound hole 121a (first sound hole) towards region 131 (first region). In this example, region 131 (first region) is located on the B1 direction (first direction) side of region 132 (second region), and the outer surface region 130 guides the acoustic signal AC1 emitted from the sound hole 121a towards the B1 direction. For example, the opening end 131b of the tone hole 121a (first tone hole) faces a space SP surrounded by region 132 (second region), and the region 131 (first region) side of space SP is open to the outer periphery of space SP (outward in the B1 direction). In other words, for example, region 132 is a convex-shaped region in which its surface 132a protrudes outward (in the D1 direction) than the surface 131a of region 131, and surrounds the region around the opening end 131b, excluding the region 131 (first region) side (in the B1 direction). To put it another way, for example, region 131 is recessed compared to region 132, and region 132 is curved so as to partially surround the opening end 131b of region 131. In other words, in this example, region 131 is located on the B1 direction (first direction) side of the opening end 131b of the sound hole 121a, and region 132 is a region that bulges out to surround the opening end 131b, except for a portion of the area on the B1 direction side of the 360-degree radial direction. For example, region 132 has a mountain-like shape with a maximum portion at one or more locations. Also, the surface 132a of region 132 in this example is connected to the surface 131a of region 131 via the inclined portion 132c of region 132. That is, the inclined portion 132c in this example has a tapered shape that widens from surface 131a to surface 132a. In this case, when the acoustic signal output device 10 is attached, the acoustic signal AC1 emitted from the sound hole 121a can be efficiently guided to the user's ear canal side, which is located on the region 131 side (B1 direction side). However, the opening end 131b side of region 132 does not have to be tapered.Furthermore, the opening end of the sound hole 123a (second sound hole) faces the space outside the space SP surrounded by region 132 (second region). More specifically, the opening end of the sound hole 123a (second sound hole) in this embodiment faces the space outside the space surrounded by the outer surface region 130. In addition to this, as mentioned above, the sound hole 123a (second sound hole) is positioned biased toward the B2 direction (second direction). As a result, the acoustic signal AC2 emitted from the sound hole 123a is less likely to reach the user's ear canal than the acoustic signal AC1 emitted from the sound hole 121a.

[0019] The shape of the support portion 13 illustrated is merely an example and does not limit the present invention. For example, if the surface 132a of region 132 protrudes in the D1 direction more than the surface 131a of region 131, then the surface 131a of region 131 and the surface 132a of region 132 may be convex, concave, uneven, or flat. However, a curved convex shape of the surface 132a of region 132 provides a better fit when worn. Furthermore, there are no limitations on the material that constitutes the support portion 13. The support portion 13 may be made of a rigid material such as synthetic resin, or it may be made of an elastic material such as rubber or urethane. However, a fit when worn is better if region 132 is made of an elastic material.

[0020] <Wearing condition> Figure 5 illustrates the mounting state of the acoustic signal output device 10. In this embodiment, the acoustic signal output device 10 is mounted on the auricle 1010 (body) of the user 1000 such that the support portion 13 faces the auricle 1010. When the housing 12 and the support portion 13 (structural portion) are attached to the auricle 1010 of the user 1000 in this manner, the region 132 (second region) of the support portion 13 is supported by contacting some part of the auricle 1010 (body), and the opening end 131b of the sound hole 121a (first sound hole) and the region 131 (first region) of the support portion 13 do not come into contact with at least a part of the auricle 1010 (body), and the region 131 (first region) is positioned towards the external auditory canal 1011. For example, when the acoustic signal output device 10 is worn, region 132 is positioned above the auricle 1010, and the surface 132a of region 132 contacts and supports the upper part of the auricle 1010 (e.g., the triangular fossa or scaphoid fossa). This prevents the sound hole 121a from contacting and blocking any part of the user's auricle 1010. In addition, since region 131 contacts the auricle 1010 and acts as support, the device feels very stable when worn. In particular, if region 131 has a convex shape, it fits the concave shape of the auricle 1010 and acts as support, increasing the stability when worn. This effect is greater if region 131 is elastic rather than rigid. When the acoustic signal output device 10 is worn, for example, region 131 is positioned below region 132 (towards the external auditory canal 1011). As described above, the outer surface region 130 of the support portion 13 is shaped to guide the acoustic signal AC1 (first acoustic signal) emitted from the sound hole 121a (first sound hole) toward the region 131 (first region) side (B1 direction side). Therefore, the acoustic signal AC1 emitted from the sound hole 121a is guided toward the external auditory canal 1011 side (below the auricle 1010) and emitted therefrom. Since the region 132 supported by the auricle 1010 protrudes more than region 131, the open end 131b and at least a part of region 131 do not come into contact with the auricle 1010. Preferably, the open end 131b and region 131 do not come into contact with the auricle 1010. Furthermore, the support portion 13 does not block the external auditory canal 1011. As a result, the acoustic signal AC1 emitted from the sound hole 121a reaches the external auditory canal 1011 efficiently.As mentioned above, if the inclined portion 132c of the support portion 13 has a tapered shape that widens from surface 131a to surface 132a, the acoustic signal AC1 emitted from the sound hole 121a reaches the external auditory canal 1011 more efficiently. On the other hand, since the B2 direction side of the opening end 131b of the sound hole 121a is surrounded by region 132, leakage of the acoustic signal AC1 emitted from the sound hole 121a to the B2 direction side (sound leakage) can be suppressed. In other words, when the housing 12 and the support portion 13 (structural portion) are attached to the auricle 1010 (body), the sound pressure level of the acoustic signal AC1 (first acoustic signal) emitted from the external auditory canal 1011 to the external auditory canal 1011 side becomes higher than the sound pressure level of the acoustic signal AC1 (first acoustic signal) emitted from outside the external auditory canal 1011 to a side other than the external auditory canal 1011 side.

[0021] Furthermore, the opening end of the sound hole 123a (second sound hole) in this embodiment faces the space outside the space SP surrounded by the region 132 (second region). Also, the sound hole 123a (second sound hole) is positioned biased toward the B2 direction (second direction). As a result, the acoustic signal AC2 emitted from the sound hole 123a is less likely to reach the external auditory canal 1011 of the user 1000 compared to the acoustic signal AC1 emitted from the sound hole 121a. Furthermore, this acoustic signal AC2 cancels out the acoustic signal AC1 that has leaked to the outside, suppressing sound leakage. This will be explained using Figures 6A and 6B. In the example in Figure 6A, one acoustic signal output device 10 is attached to the right ear auricle 1010 and the left ear auricle 1020 of the user 1000. Any attachment mechanism can be used to attach the acoustic signal output device 10 to the ear. As described above, the acoustic signal output devices 10 are each positioned so that the D1 direction side faces the user 1000. The output signal output from the playback device 100 is input to the driver unit 11 of each acoustic signal output device 10, and the driver unit 11 emits acoustic signal AC1 in the D1 direction and acoustic signal AC2 in the other direction. Acoustic signal AC1 is emitted from the sound hole 121a, and the emitted acoustic signal AC1 enters the external auditory canals 1011 of the right and left ears and is heard by the user 1000. On the other hand, acoustic signal AC2, which is the inverse phase signal of acoustic signal AC1 or an approximate signal of the inverse phase signal, is emitted from the sound hole 123a. A portion of this acoustic signal AC2 cancels out a portion of acoustic signal AC1 emitted from the sound hole 121a (sound leakage component). In other words, when an acoustic signal AC1 (first acoustic signal) is emitted from the tone hole 121a (first tone hole) and an acoustic signal AC2 (second acoustic signal) is emitted from the tone hole 123a (second tone hole), the attenuation rate η of the acoustic signal AC1 (first acoustic signal) at position P2 (second point) relative to position P1 (first point) is 11 a predetermined value η th The following can be determined, and the attenuation η of the acoustic signal AC1 (first acoustic signal) at position P2 (second point) relative to position P1 (first point) 12 A predetermined value ω thcan be achieved as described above. Here, the position P1 (the first point) is a predetermined point where the acoustic signal AC1 (the first acoustic signal) emitted from the sound hole 121a (the first sound hole) arrives. On the other hand, the position P2 (the second point) is a predetermined point that is farther from the acoustic signal output device 10 than the position P1 (the first point). The positions P1 and P2 can be any points. For example, the positions P1 and P2 are positions in a direction other than the B1 direction of the acoustic signal output device 10, and for example, they are positions in the B2 direction or the D2 direction of the acoustic signal output device 10. The predetermined value η th is the attenuation rate η of an arbitrary or specific acoustic signal (sound) by air propagation at the position P2 (the second point) based on the position P1 (the first point) 21 and is a smaller value (lower value). Also, the predetermined value ω th is the attenuation amount η of an arbitrary or specific acoustic signal (sound) by air propagation at the position P2 (the second point) based on the position P1 (the first point) 22 and is a larger value. That is, the acoustic signal output device 10 of the present embodiment is designed such that the attenuation rate η 11 is less than or equal to a predetermined value η 21 that is smaller than the attenuation rate η th , or the attenuation amount η 12 is greater than or equal to a predetermined value ω 22 that is larger than the attenuation amount η th . Note that the acoustic signal AC1 is propagated through the air from the position P1 to the position P2 and attenuates due to this air propagation and the acoustic signal AC2. The attenuation rate η 11 is the ratio (AMP2(AC1) / AMP1(AC1)) of the magnitude AMP2(AC1) of the acoustic signal AC1 at the position P2, which has attenuated due to air propagation and the acoustic signal AC2, to the magnitude AMP1(AC1) of the acoustic signal AC1 at the position P1. Also, the attenuation amount η 12 is the difference (|AMP1(AC1) - AMP2(AC1)|) between the magnitude AMP1(AC) and the magnitude AMP2(AC). On the other hand, when the acoustic signal AC2 is not assumed, an arbitrary or specific acoustic signal AC ar propagated through the air from the position P1 to the position P2 attenuates due to air propagation without being caused by the acoustic signal AC2. The attenuation rate η​The acoustic signal AC at position P1 is ar Size AMP1 (AC ar ) The acoustic signal AC at position P2, which is attenuated due to air propagation (attenuated without being caused by the acoustic signal AC2) ar Size AMP2 (AC ar ) ratio (AMP2(AC ar ) / AMP1(AC ar )) is the case. Also, the attenuation η 22 The size is AMP1(AC ar ) and size AMP2 (AC ar ) difference (|AMP1(AC ar )-AMP2(AC ar )|). Examples of the magnitude of an acoustic signal include the sound pressure or energy of the acoustic signal. Furthermore, "sound leakage component" refers to a component of the acoustic signal AC1 emitted from the sound port 121a that is likely to reach areas other than the user 1000 wearing the acoustic signal output device 10 (for example, a person other than the user 1000 wearing the acoustic signal output device 10). For example, "sound leakage component" refers to a component of the acoustic signal AC1 that propagates in directions other than the D1 direction. For example, the direct wave of the acoustic signal AC1 is mainly emitted from the sound port 121a, and the direct wave of the second acoustic signal is mainly emitted from the second sound port. A portion of the direct wave of the acoustic signal AC1 emitted from the sound port 121a (sound leakage component) is canceled out by interference with at least a portion of the direct wave of the acoustic signal AC2 emitted from the sound port 123a. However, this does not limit the present invention, and this cancellation can occur with waves other than direct waves. In other words, the sound leakage component, which is at least one of the direct and reflected waves of the acoustic signal AC1 emitted from the sound hole 121a, may be canceled out by at least one of the direct and reflected waves of the acoustic signal AC2 emitted from the sound hole 123a. This suppresses sound leakage.

[0022] Furthermore, because the sound hole 123a (second sound hole) is positioned biased toward the B2 direction (second direction), the acoustic signal AC2 emitted from the sound hole 123a does not easily reach the ear canal 1011. Therefore, on the ear canal 1011 side, the acoustic signal AC1 is not easily canceled out by the acoustic signal AC2. In other words, because the sound hole 123a is far from the ear canal 1011, the acoustic signal AC2 emitted from the sound hole 123a does not easily cancel out the acoustic signal AC1 emitted from the sound hole 121a toward the ear canal 1011. To put it another way, the acoustic signal AC2 can suppress sound leakage of the acoustic signal AC1 that has leaked to a side other than the ear canal 1011 without significantly suppressing the acoustic signal AC1 emitted toward the ear canal 1011. For example, when the acoustic signal output device 10 is attached to the auricle 1010, it is desirable that the distance from the external auditory canal 1011 to the sound hole 121a be 2 cm or more and 3 cm or less, and the distance from the sound hole 121a to the sound hole 123a be 2 cm or more. However, this does not limit the present invention.

[0023] <Left unattended> As illustrated in Figure 7, the state in which the acoustic signal output device 10 is placed on a flat surface 1100 such as a desk is described. In Figure 7, the support portion 13 side is positioned on the flat surface 1100. Even in this case, since region 132 protrudes more than region 131, the opening end 131b of the sound hole 121a and at least a part of region 131 do not come into contact with the flat surface 1100. Therefore, the acoustic signal AC1 emitted from the opening end 131b of the sound hole 121a and the acoustic signal AC2 emitted from the sound hole 123a cancel each other out as described above, and sound leakage can be suppressed. In other words, in this embodiment, the position, size, shape, and angle of the surface 132a of region 132 are set so that the opening end 131b of the sound hole 121a and at least a part of region 131 do not come into contact with the flat surface 1100.

[0024] Such effects can also be obtained when the housing 12 is positioned on a plane 1100. That is, regardless of the orientation in which the acoustic signal output device 10 of this embodiment is positioned on the plane 1100, the acoustic signal AC1 emitted from the opening end 131b of the sound hole 121a and the acoustic signal AC2 emitted from the sound hole 123a cancel each other out as described above, thereby suppressing sound leakage.

[0025] [Modified version of the first embodiment] The shape, size, and arrangement of the sound holes 121a and 123a are not limited to those illustrated in the first embodiment. For example, the first embodiment showed an example in which one sound hole 121a is provided in region AR1 of the housing 12, and the open end 131b of one sound hole 121a is provided in the support portion 13. However, as illustrated in Figure 8A, multiple sound holes 121a may be provided in region AR1 of the housing 12, and multiple open ends 131b of multiple sound holes 121a may be provided in the support portion 13. In this case, these multiple sound holes 121a and their open ends 131b may be offset to eccentric positions shifted from axis A1 in the direction of B1.

[0026] In the first embodiment, an example was shown in which sound holes 123a of the same shape and size are arranged on the same circumference of the wall portion 123 of the housing 12. However, the shape and size of the sound holes 123a can be anything as long as the opening end of the sound hole 123a faces the space outside the space SP surrounded by region 132, and the sound holes 123a are arranged biased toward the B2 direction. That is, the sound pressure level of the acoustic signal AC2 emitted from the sound hole 123a to space SP1 should be lower than the sound pressure level of the acoustic signal AC2 emitted from the sound hole 123a to space SP2. As described above, space SP1 is a space located on the B1 direction side with respect to the sound hole 121a, and space SP2 is a space located on the B2 direction side with respect to the sound hole 121a.

[0027] For example, as illustrated in Figure 8B, multiple tone holes 123a (second tone holes) of different sizes may be provided, or as illustrated in Figure 8C, multiple tone holes 123a (second tone holes) of different shapes may be provided, and the multiple tone holes 123a do not have to be arranged on the same circumference.

[0028] For example, as illustrated in Figures 9A and 9B, sound holes 123a may also be provided on the B1 side of axis A1. Even in this case, it is sufficient that the opening area of ​​the sound holes 123a located on the B1 side of axis A1 is smaller than the opening area of ​​the sound holes 123a located biased towards the B2 side, or that the opening area per unit area (i.e., the density of the opening area) of the sound holes 123a located on the B1 side of axis A1 is smaller than the opening area per unit area of ​​the sound holes 123a located biased towards the B2 side. This is because the total area of ​​the opening ends of the sound holes 123a facing space SP1 becomes smaller than the total area of ​​the opening ends of the sound holes 123a facing space SP2, and the sound pressure level of the acoustic signal AC2 emitted from the sound holes 123a to space SP1 becomes lower than the sound pressure level of the acoustic signal AC2 emitted from the sound holes 123a to space SP2. For example, the opening area of ​​the opening end of a tone hole 123a at a distance α1 from the opening end 131b of tone hole 121a may be designed to be smaller than the opening area of ​​the opening end of a tone hole 123a at a distance α2 from the opening end 131b of tone hole 121a, provided that α1 < α2. For example, the opening area of ​​the opening end of a tone hole 123a may be smaller the closer it is to the opening end 131b of tone hole 121a.

[0029] Furthermore, as illustrated in Figures 10A and 10B, even if the sound holes 123a are located on the B1 side of axis A1, it is sufficient that the sound pressure level of the acoustic signal AC2 emitted from them is lower than the sound pressure level of the acoustic signal AC2 emitted from the sound holes 123a that are biased towards the B2 side. For example, the acoustic signal AC2 emitted from the driver unit 11 may be directional, thereby causing the sound pressure level of the acoustic signal AC2 emitted from the sound holes 123a located on the B1 side of axis A1 to be lower than the sound pressure level of the acoustic signal AC2 emitted from the sound holes 123a that are biased towards the B2 side. Alternatively, multiple driver units 11 with different output powers may be housed inside the housing 12, thereby causing the sound pressure level of the acoustic signal AC2 emitted from the sound holes 123a located on the B1 side of axis A1 to be lower than the sound pressure level of the acoustic signal AC2 emitted from the sound holes 123a that are biased towards the B2 side. Alternatively, a material that attenuates acoustic signals may be placed at the opening of the sound hole 123a located on the B1 side of axis A1, or the opening of the sound hole 123a located on the B1 side of axis A1 may have a shape such as a mesh structure that attenuates acoustic signals. In other words, the housing 12 is provided with a plurality of sound holes 123a (second sound holes), and the sound pressure level of the acoustic signal AC2 (second acoustic signal) emitted from the opening end of the sound hole 123a (second sound hole) facing space SP1 (first space) is lower than the sound pressure level of the acoustic signal AC2 (second acoustic signal) emitted from the opening end of the sound hole 123a (second sound hole) facing space SP2 (second space). The sound pressure level of the acoustic signal AC2 emitted from the opening end of a sound hole 123a at a distance α1 from the opening end 131b of a sound hole 121a may be designed to be lower than the sound pressure level of the acoustic signal AC2 emitted from the opening end of a sound hole 123a at a distance α2 from the opening end 131b of a sound hole 121a, provided that α1 < α2. For example, the sound pressure level of the emitted acoustic signal AC2 may be lower for sound holes 123a that are closer to the opening end 131b of a sound hole 121a.

[0030] Furthermore, although the first embodiment showed an example in which multiple sound holes 123a are provided in the housing 12, the housing 12 may have only one sound hole 123a. In this case, it is desirable that the opening end of the sound hole 123a be as far away as possible from the sound hole 121a. Preferably, the sound hole 123a is provided such that the distance between the opening end of the sound hole 123a and the sound hole 121a is maximized.

[0031] [Second Embodiment] Next, a second embodiment will be described. The second embodiment is a further modification of the first embodiment and its modified form. In the following, the differences from the matters described so far will be the focus of the explanation, and matters that have already been explained will be simplified.

[0032] The acoustic signal output device 10 illustrated in the first embodiment suppresses sound leakage by emitting an acoustic signal AC2 from the sound hole 123a, thereby canceling out the acoustic signal AC1 that has leaked to the outside from the sound hole 121a. Ideally, this is based on the fact that the acoustic signal AC2 is in opposite phase to the acoustic signal AC1. However, because the propagation paths of the acoustic signal AC1 and the acoustic signal AC2 are different, a phase difference occurs between the acoustic signals AC1 and AC2, and there are cases where the acoustic signal AC2 is not in opposite phase to the acoustic signal AC1 at the point where sound leakage is to be suppressed. This effect becomes larger as the frequencies of the acoustic signals AC1 and AC2 increase, making it difficult to suppress sound leakage at higher frequencies. In some cases, the acoustic signal AC2 does not cancel out the acoustic signal AC1, and instead, the acoustic signal AC2 is also perceived as a sound leakage component. For example, the sound leakage of the acoustic signal AC1 can be suppressed by the acoustic signal AC2 only when the frequencies of the acoustic signals AC1 and AC2 are up to about 3 kHz, and at higher frequency bands, the acoustic signal AC2 also becomes a sound leakage component.

[0033] Furthermore, the human ear is sensitive to the 3kHz-6kHz frequency range, and in this range, even quiet sounds are perceived as louder compared to other frequency ranges. This characteristic of human hearing can be represented as equal-loudness curves. These equal-loudness curves connect the sound pressure levels at which sounds of various frequencies are perceived as having the same loudness. Figure 13 shows the equal-loudness curves. In Figure 13, the horizontal axis represents frequency [Hz], and the vertical axis represents sound pressure level [dB]. As shown in Figure 13, the equal-loudness curves are minimal around 4kHz, indicating that human hearing sensitivity is high at this frequency. Therefore, it is desirable to lower the sound pressure level of the acoustic signal AC2 in the 3kHz-6kHz frequency range, where human hearing sensitivity is high.

[0034] As mentioned above, the acoustic signal AC2 emitted from the driver unit 11 is emitted into region AR, which is the internal space of the housing 12 (enclosure), and is further emitted to the outside through the sound holes 123a. The sound pressure level of the acoustic signal AC2 is maximum at the resonant frequency of this region AR. Therefore, in order to suppress sound leakage on the high-frequency side, it is desirable to set this resonant frequency to be above the frequency range in which human hearing sensitivity is high (for example, 6kHz or higher). Figure 14A illustrates the relationship between the volume of region AR and the acoustic signal AC2 emitted to the outside through the sound holes 123a. As illustrated in Figure 14A, it can be seen that the smaller the volume of region AR, the higher the resonant frequency fr. Therefore, it is thought that the effect of sound leakage can be reduced by reducing the volume of region AR and setting the resonant frequency of region AR to be above the frequency range in which human hearing sensitivity is high (for example, 6kHz or higher).

[0035] However, if the resonant frequency of region AR is set above the frequency range in which human hearing is highly sensitive, the sound pressure level will also increase in the frequency range surrounding this resonant frequency, and the sound pressure level in the frequency range in which human hearing is highly sensitive will also increase. Therefore, in this embodiment, measures are taken to further reduce the high-frequency side of the acoustic signal AC2 emitted to the outside from the sound hole 123a. This makes it possible to reduce sound leakage in the frequency range in which human hearing is highly sensitive (for example, the 3kHz-6kHz range).

[0036] The acoustic signal output device 20 of this embodiment includes a driver unit 11, a housing 12 (structural part) that houses the driver unit 11, and a support part 13 (structural part) that is positioned on the user's auricle when worn. The housing 12 (structural part) is provided with one or more sound holes 121a (first sound holes) for emitting an acoustic signal AC1 (first acoustic signal) to the outside, a hollow part from which an acoustic signal AC2 (second acoustic signal) is emitting into a region AR (internal space), and one or more sound holes 123a (second sound holes) for emitting the acoustic signal AC2 (second acoustic signal) emitted into the region AR (internal space) of the hollow part to the outside. Here, the design ensures that the resonant frequency of the hollow section is above a predetermined frequency (for example, above the frequency range in which human hearing is highly sensitive, e.g., 6kHz or higher), and that an acoustic signal AC2 (second acoustic signal) is emitted to the outside from the sound hole 123a (second sound hole) with frequency band components including the predetermined frequency (for example, frequency band components in which human hearing is highly sensitive, e.g., 3kHz-6kHz band components) suppressed. This reduces sound leakage in the frequency range in which human hearing is highly sensitive (e.g., the 3kHz-6kHz band). An example of such a design is shown below.

[0037] <Design Example 1> As illustrated in Figure 11A, the housing 12 (structural part) of the acoustic signal output device 20 may have an internal hollow part 241 located in the region AR (internal space) of its hollow part 220. The internal space ISP of the internal hollow part 241 is spatially separated from the region AR (internal space) of the hollow part 220 located outside the internal hollow part 241. That is, the internal hollow part 241 is a hollow member with a wall portion 242 on the outside, and its internal space ISP is spatially separated from the region AR by the wall portion 242. The shape of the internal hollow part 241 can be anything as long as it has such an internal space ISP. There are no limitations on the material that constitutes the wall portion 242. The wall portion 242 may be made of a rigid body such as synthetic resin or metal, or it may be made of an elastic body such as rubber. Furthermore, the internal space ISP of the internal hollow part 241 only needs to be spatially separated from the region AR, and may or may not be completely sealed. The internal space ISP may be filled with air, other gases, or even an elastic material. However, it is desirable that the material placed in the internal space ISP be softer than the wall portion 242. In this example, the bottom portion 242a of the wall portion 242 of the internal hollow portion 241 is fixed to the region AR2 inside the hollow portion 220. However, this is just an example, and any region of the wall portion 242 of the internal hollow portion 241 may be fixed to any region inside the hollow portion 220. By placing the internal hollow portion 241 in the region AR of the hollow portion 220, and creating a double structure with the hollow portion 220 and the internal hollow portion 241, the volume of region AR can be reduced, and the resonant frequency of the hollow portion 220 can be increased. Therefore, by appropriately designing the volume of the internal hollow portion 241, the resonant frequency of the hollow portion 220 can be set to a frequency band where human hearing sensitivity is high or higher (for example, 6 kHz or higher). In particular, the internal hollow section 241 offers a high degree of design flexibility, allowing its shape and size to be set so that the volume of region AR is sufficiently small. For example, it is possible to design the internal hollow section 241 so that it does not touch the driver unit 11 and is as close to the driver unit 11 as possible, thereby making the resonant frequency of the hollow section 220 sufficiently large.Furthermore, the air in the internal space ISP of the internal hollow section 241 acts as a damper, reducing vibrations in the hollow section 220, thereby suppressing the high-frequency band components of the acoustic signal AC2 (second acoustic signal) emitted to the outside from the sound hole 123a (second sound hole).

[0038] <Design Example 2> As illustrated in Figure 11B, a cushioning material 25 may be placed between the bottom surface 242a (outside) of the internal hollow section 241 and the region AR2 (inside) of the hollow section 220, and the bottom surface 242a (outside) of the internal hollow section 241 may be fixed to the region AR2 (inside) of the hollow section 220 via the cushioning material 25. In this example, the cushioning material 25 is placed on the bottom surface 242a of the internal hollow section 241, but the cushioning material 25 may also be placed between the other wall portion 242 of the internal hollow section 241 and the inside of the hollow section 220, and the other wall portion 242 of the internal hollow section 241 may be fixed to the inside of the hollow section 220 via the cushioning material 25. The cushioning material 25 is softer than the wall portion 122 of the housing 12 and the wall portion 242 of the internal hollow section 241, thereby further reducing vibrations of the hollow section 220. This makes it possible to suppress the high-frequency band components of the acoustic signal AC2 emitted to the outside from the sound hole 123a. Examples of materials for the cushioning material 25 include paper, urethane, and rubber, and for example, paper double-sided tape may be used as the cushioning material 25. However, this does not limit the present invention. Furthermore, if such a cushioning material 25 is provided, a solid member with a filled interior may be used instead of the internal hollow portion 241.

[0039] <Design Example 3> As illustrated in Figure 12A, at least a portion of the electronic components 26 for driving the driver unit 11 may be housed in the internal space ISP of the internal hollow portion 241. This allows the internal space ISP, which acts as a damper, to be repurposed as a space for arranging the electronic components 26, thereby enabling miniaturization of the housing 12. Examples of electronic components 26 include wiring cables, electronic components, and electronic circuit boards. Considering its function as a damper, it is desirable that the electronic components 26 be made of a material softer than the wall portion 242, such as a wiring cable. Furthermore, as explained in Design Example 2, a buffer material 25 may be placed between the bottom surface 242a (outside) of the internal hollow portion 241 and the region AR2 (inside) of the hollow portion 220, and the bottom surface 242a (outside) of the internal hollow portion 241 may be fixed to the region AR2 (inside) of the hollow portion 220 via the buffer material 25.

[0040] <Design Example 4> In addition to the configurations described in design examples 1 to 3, the driver unit 11 may further emit an acoustic signal AC2 (second acoustic signal) into the region AR (internal space) of the hollow section 220, in which frequency band components including the aforementioned predetermined frequency (for example, a band in which human hearing is highly sensitive, for example, 6kHz) are suppressed (for example, a band in which human hearing is highly sensitive, for example, a band in the 3kHz-6kHz range). For example, as illustrated in Figure 12B, an LPF (low-pass filter) section 200 may be provided between the playback device 100, which outputs an output signal for driving the driver unit 11, and the driver unit 11. This low-pass filter suppresses (attenuates or flattens) frequency band components including the aforementioned predetermined frequency (for example, a band in which human hearing is highly sensitive). For example, the cutoff frequency of this low-pass filter is set to 3kHz. The output signal output from the playback device 100 is input to the LPF section 200, and the LPF section 200 outputs a low-pass output signal in which the high-frequency side of this output signal is attenuated. The low-pass output signal is input to the driver unit 11, and the driver unit 11 is driven based on the low-pass output signal. As a result, the driver unit 11 emits an acoustic signal AC2 (second acoustic signal) into the region AR (internal space) of the hollow section 220, in which frequency band components including the aforementioned predetermined frequency (for example, a band in which human hearing is highly sensitive, for example, 6kHz) (for example, a band in which human hearing is highly sensitive, for example, a band in the 3kHz-6kHz range) are suppressed. The acoustic signal AC2 (second acoustic signal) emitted into the region AR (internal space) of the hollow section 220 is further emitted to the outside from the sound hole 123a. The LPF section 200 may be implemented using electronic components such as coils and capacitors, or it may be implemented by digital processing. If the LPF section 200 is configured with electronic components such as resistors and capacitors, a power supply to drive the LPF section 200 is not required. In this case, a wired acoustic signal output device 20 that does not require a power supply can also be used. The LPF section 200 may be provided outside the housing 12, or it may be provided on the housing 12 itself.

[0041] <Design Example 5> As illustrated in Figure 12B, a switching unit 210 may be provided to switch whether the driver unit 11 emits an acoustic signal AC2 (second acoustic signal) with frequency band components including the predetermined frequency (for example, a band in which human hearing is highly sensitive, for example, 6kHz) suppressed (for example, a band in which human hearing is highly sensitive, for example, a band in the 3kHz-6kHz range) into the region AR (internal space) of the hollow section 220, or whether the driver unit 11 emits an acoustic signal AC2 (second acoustic signal) without suppressing the frequency band components including the predetermined frequency into the region AR (internal space) of the hollow section 220. For example, the switching unit 210 switches whether or not to use the LPF section 200 of design example 4. When switched to use the LPF section 200, as explained in design example 4, a low-pass output signal via the LPF section 200 is input to the driver unit 11, and the driver unit 11 is driven based on this low-pass output signal. On the other hand, when the LPF section 200 is switched off, the output signal from the playback device 100 is directly input to the driver unit 11, and the driver unit 11 is driven based on this output signal. By operating such a switching unit 210, the user can suppress high-frequency sound leakage by emitting acoustic signals AC1 and AC2 with the aforementioned frequency band components suppressed in environments where sound leakage is a concern, and emit acoustic signals AC1 and AC2 without suppressing the aforementioned frequency band components in environments where external noise is high and sound leakage is not a concern. In the latter case, the aforementioned frequency band components (for example, frequency band components to which human hearing is highly sensitive, for example, the 3kHz-6kHz frequency band component) are not suppressed, so music and voices can be heard even in high-noise environments. The switching unit 210 may be provided on the outside of the housing 12 or on the housing 12 itself.

[0042] <Design Example 6> Instead of using the LPF section 200 in design example 4, the high-frequency components (frequency band components including the predetermined frequencies mentioned above) of the acoustic signal AC2 (second acoustic signal) emitted from the driver unit 11 may be suppressed based on the structure of the driver unit 11. For example, if the diaphragm of the driver unit 11 is a dynamic type with a cone, the stiffness sh of the cone's neck should be designed so that the high-frequency reproduction limit frequency fh of the cone becomes the upper limit of the band in which human hearing sensitivity is high (for example, the 3kHz-6kHz band component) (for example, 6kHz or nearby). The high-frequency reproduction limit frequency fh and stiffness sh satisfy the following relationship. fh = (1 / (2π)) × √(sh / M) However, M is the mass of the vibrating system including the cone paper. In other words, the softer the material of the diaphragm of the driver unit 11, the lower the high-frequency reproduction limit frequency fh can be. Alternatively, such a driver unit 11 may be combined with the LPF section 200 of design example 4.

[0043] <Experimental Results> Figure 14B illustrates the sound pressure levels with and without the LPF 200. As illustrated in Figure 14B, using the LPF 200 suppresses the sound pressure level in the frequency band where human hearing is highly sensitive (for example, the 3kHz-6kHz band component), thereby reducing sound leakage.

[0044] [Third Embodiment] In the third embodiment, we illustrate the mounting method of the acoustic signal output device described above.

[0045] <Installation Method 1> In the example shown in Figure 15, one end 311 of a curved, rod-shaped ear hook portion 310 is fixed to the outside of the housing 12. By attaching this ear hook portion 310 to the auricle, the acoustic signal output device 10(20) can be attached as shown in Figure 5. In this example, one end 311 of the ear hook portion 310 is fixed to the region 132 (second region) side, not the region 131 (first region) side. As a result, the acoustic signal AC1 (first acoustic signal) emitted to the region 131 side is emitted into the external auditory canal 1011 without being obstructed by the ear hook portion 310.

[0046] <Installation Method 2> The acoustic signal output device 30 illustrated in Figures 16A to 16C is an integrated version of the aforementioned acoustic signal output device 10(20) with the temple 33 of the eyeglasses. In this example, region 131 (first region) of the support region 13 is located on the ear hook portion 33a side (B1 direction side) of the temple 33 that is attached to the auricle 1020, and region 132 (second region), which protrudes more than region 131 (first region), is located on the lens 34 side (B2 direction side). Region 131 (first region) protrudes inward (D1 direction) of the temple 33, and as described above, it is configured to guide the acoustic signal AC1 (first acoustic signal) emitted from the sound hole 121a (first sound hole) towards region 131 (first region) (B1 direction side). When wearing such glasses, the region 132 (second region) of the support part 13 is supported by contact with some part of the head (body), and the opening end 131b of the sound hole 121a (first sound hole) and the region 131 (first region) of the support part 13 are positioned on the external auditory canal 1011 side without contacting at least part of the head (body). The acoustic signal AC1 emitted from the sound hole 121a is guided and emitted towards the external auditory canal 1021 side (below the auricle 1020).

[0047] <Mounting Method 3> As illustrated in Figure 17, the acoustic signal output device 3100 of the mounting method 3 includes a structural part 2112 including a housing and a support part, and a mounting part 2122 configured to hold the structural part 2112 and be mounted on the intermediate part 1023 of the auricle 1020. The intermediate part 1023 is the intermediate part between the upper part 1022 (helix side) and the lower part 1024 (lobe side) of the auricle 1020. The structural part 2112 is the housing 12 and support part 13 illustrated in the first embodiment, its modified form, or the second embodiment.

[0048] <Mounting Method 4> As illustrated in Figure 18A, the acoustic signal output device 4100 of the mounting method 4 has a structural part 2112 including a housing and a support part, and a mounting part 2224 that holds the structural part 2112 and is mounted on the upper part 1022 of the auricle 1020, which is part of the auricle 1020.

[0049] <Mounting Method 5> As illustrated in Figure 18B, the acoustic signal output device 4100' of mounting method 5 includes a structural part 2112 including a housing and a support part, a mounting part 2224 configured to hold the structural part 2112 and be mounted on the upper part 1022 of the auricle 1020, which is part of the auricle 1020, and a mounting part 4421 configured to be in contact with the concha of the auricle 1020.

[0050] <Mounting method 6> The acoustic signal output device 4200 illustrated in Figure 19 includes a structural part 2112, a columnar mounting part 4210 that holds the structural part 2112 and is configured to be positioned on the base side of the auricle 1020 when worn, and arc-shaped mounting parts 4220 that are held at both ends of the mounting part 4210 and are mounted on the area from the back side of the upper part 1022 to the lower part 1024 of the auricle 1020.

[0051] <Mounting Method 7> The acoustic signal output device 5110 of the mounting method 7 illustrated in Figures 20A to 20E has a structural part 5111 that emits an acoustic signal and a mounting part 5112 that holds the structural part 5111 and hooks onto the back side of the upper part 1022 of the auricle 1020 when worn. The structural part 5112 is the housing 12 and support part 13 illustrated in the first embodiment, its modified form, or the second embodiment. The mounting part 5112 is a bent rod-shaped member, and the structural part 5111 is attached to one end thereof so as to be rotatable in the R5 direction. The auricle 1020 is sandwiched between the structural part 5111 and the mounting part 5112, thereby fixing the acoustic signal output device 5110 to the auricle 1020. Furthermore, since the structural part 5111 is rotatable in the R5 direction relative to one end of the mounting part 5112, the mounting position and the position of the sound hole can be adjusted according to the size and shape of each individual auricle 1020.

[0052] <Mounting method 8> The acoustic signal output device 5120 of the mounting method 8 illustrated in Figures 21A to 21C has a structural part 5121 that emits an acoustic signal and a mounting part 5122 that holds the structural part 5121 and hooks onto the back of the upper part 1022 of the auricle 1020 when worn. The structural part 5121 is the housing 12 and support part 13 illustrated in the first embodiment, its modified form, or the second embodiment. Unlike mounting method 7, the structural part 5121 is not rotatable to the mounting part 5122. The auricle 1020 is sandwiched between the structural part 5121 and the mounting part 5122, thereby fixing the acoustic signal output device 5120 to the auricle 1020.

[0053] <Mounting Method 9> The acoustic signal output devices 5130 and 5140 of the mounting method 9 illustrated in Figures 22A and 22B each have a structural part 5131 and 5141 that emits an acoustic signal, and a mounting part 5132 and 5142 that hold the structural parts 5131 and 5141 and are of a type that can be hooked onto the back side of the upper part 1022 of the auricle 1020 when worn. The structural parts 5131 and 5141 are the housing 12 and support part 13 illustrated in the first embodiment, its modified form, or the second embodiment. Furthermore, the acoustic signal output device 5140 illustrated in Figure 22B is provided with a mounting part 5143 configured to contact the concha of the auricle 1020 when worn. This enables more stable mounting.

[0054] <Mounting method 10> The acoustic signal output device 5150 illustrated in Figures 23A, 23B, and 23C includes a structural part 5151 that emits an acoustic signal, a rod-shaped attachment part 5152 that holds the structural part 5151 and is hooked onto the back of the upper part 1022 of the auricle 1020 when worn, a columnar support part 5154 that holds the structural part 5151 at one end and holds the attachment part 5152 at the other end, a rod-shaped attachment part 5153 that is hooked onto the back of the middle part 1023 and upper part 1022 of the auricle 102 from the middle part 1023 side when worn, and a columnar support part 5155 that holds the structural part 5151 at one end and holds the attachment part 5153 at the other end. The structural part 5151 is the housing 12 and support part 13 illustrated in the first embodiment, its modified form, or the second embodiment. The auricle 1020 is sandwiched between the structural part 5151 and the mounting parts 5152 and 5153, thereby fixing the acoustic signal output device 5150 to the auricle 1020.

[0055] <Mounting method 12> The acoustic signal output device 5160 illustrated in Figures 24A to 24E includes a structural part 5161 that emits an acoustic signal, a columnar mounting part 5164 that holds the structural part 5161 and is configured to be positioned on the base side of the auricle 1020 when worn, a rod-shaped mounting part 5162 that is held at one end of the mounting part 5164 and is of the type that hooks onto the back side of the upper part 1022 of the auricle 1020 when worn, and a rod-shaped mounting part 5163 that is held at the other end of the mounting part 5164 and is of the type that hooks onto the back side of the lower part 1024 of the auricle 1020 when worn. The structural part 5161 is the housing 12 and support part 13 illustrated in the first embodiment, its modified form, or the second embodiment. The auricle 1020 is sandwiched between the structural part 5161 and the attachment part 5164 and the attachment parts 5152 and 5153, thereby fixing the acoustic signal output device 5160 to the auricle 1020.

[0056] <Mounting method 13> The acoustic signal output devices 5170 and 5180 illustrated in Figures 25A to 25D and Figures 26A to 26D each have a structural part 5171 and 5181 that emits an acoustic signal, a columnar mounting part 5172 and 5182 configured to be positioned on the back side of the intermediate portion 1023 of the auricle 102 when worn, and a curved band-shaped support part 5173 and 5183, one end of which holds the structural part 5171 and 5181 and the other end of which holds the mounting part 5172 and 5182. The structural parts 5171 and 5181 are the housing 12 and support part 13 illustrated in the first embodiment, its modified form, or the second embodiment. The auricle 1020 is sandwiched between the structural parts 5171 and 5181 and the mounting part 5172 and 5182, thereby fixing the acoustic signal output devices 5170 and 5180 to the auricle 1020.

[0057] <Mounting method 14> The acoustic signal output device 5190 illustrated in Figures 27A to 27C comprises a structural part 5191 that emits an acoustic signal, and a rod-shaped mounting part 5192 that holds the structural part 5191 and is configured to be positioned on the back side of the auricle 102 when worn. The structural part 5191 is the housing 12 and support part 13 illustrated in the first embodiment, its modified form, or the second embodiment. The mounting part 5192 holds the structural part 5191 at one end on the side that is positioned on the lower part 1024 of the auricle 1020 when worn. The auricle 1020 is sandwiched between the structural part 5191 and the mounting part 5192, thereby fixing the acoustic signal output device 5190 to the auricle 1020.

[0058] <Mounting method 15> The acoustic signal output device 5200 illustrated in Figures 28A to 28E comprises a structural part 5201 that emits an acoustic signal and an annular mounting part 5202 that holds the structural part 5021. The structural part 5201 is the housing 12 and support part 13 illustrated in the first embodiment, its modified form, or the second embodiment. When worn, the auricle 1020 is inserted into the annular mounting part 5202, and the mounting part 5202 is positioned on the back side of the upper part 1022, the middle part 1023, and the lower part 1024 of the auricle 1020. At this time, the auricle 1020 is sandwiched between the structural part 5201 and the mounting part 5202, thereby fixing the acoustic signal output device 5200 to the auricle 1020.

[0059] <Mounting method 16> As illustrated in Figure 29A, the acoustic signal output device 5250 may have a structural part 5251 fixed to a curved rod-shaped mounting part 5352 that is shaped to be attached to the back of the user's head and auricle 1020. The structural part 5251 is the housing 12 and support part 13 illustrated in the first embodiment, its modified form, or the second embodiment. The mounting part 5352 is attached to the back of the user's head and auricle 1020, and the housing 12 and support part 13 are arranged as described above.

[0060] <Mounting method 17> The acoustic signal output device 5600 illustrated in Figure 29B comprises the aforementioned driver unit 11 (not shown), a roughly spherical housing 5612 (structural part) housing the driver unit 11, a roughly spherical mounting part 5601 positioned on the auricle when worn, and a curved elastic part 5602 connecting the housing 5612 and the mounting part 5601. The housing 5612 is provided with a sound hole 121a (first sound hole) for releasing (leading out) the acoustic signal AC1 (first acoustic signal) emitted from the driver unit 11 to the outside, and a sound hole 123a (second sound hole) for releasing (leading out) the acoustic signal AC2 (second acoustic signal) emitted from the driver unit 11 to the outside. Here, the design may be such that the sound pressure level of the acoustic signal AC2 emitted to the outside from the sound hole 123a is higher the further away the space is from the sound hole 121a. When the acoustic signal output device 5600 is attached, the housing 5312 is positioned on the front side (ear canal side) of the auricle with the sound hole 121a facing the ear canal, and the attachment part 5601 is positioned on the back side (side where there is no ear canal), and the auricle is sandwiched between the housing 5312 and the attachment part 5601.

[0061] [Fourth Embodiment] In this embodiment, an example is provided of an acoustic signal output device that is partially fitted inside the ear canal but does not completely seal the ear canal.

[0062] <Example 4-1> As illustrated in Figures 30A to 30C, the acoustic signal output device 5300 in this example includes the aforementioned driver unit 11, a housing 5312 (structural part) that houses the driver unit 11, and a support part 5313 (structural part) that is positioned in the user's ear canal when worn.

[0063] <Enclosure 5312> The housing 5312 is a hollow component with an external wall, housing the driver unit 11 inside. For example, the driver unit 11 is fixed to the end of the housing 5312 on the D1 direction side. However, this does not limit the present invention. There are no limitations on the shape of the housing 5312.

[0064] <Sound holes 121a, 123a> The wall of the housing 5312 is provided with a sound hole 121a (first sound hole) for releasing (leading out) the acoustic signal AC1 (first acoustic signal) emitted from the driver unit 11 to the outside, and a sound hole 123a (second sound hole) for releasing (leading out) the acoustic signal AC2 (second acoustic signal) emitted from the driver unit 11 to the outside.

[0065] In this example, the sound hole 121a (first sound hole) is provided in a region AR1 (first region) of the wall located on one side of the driver unit 11 (the side in the D1 direction from which the acoustic signal AC1 is emitted). In this example, the sound hole 121a is positioned eccentrically, offset from axis A1 (central axis of the structural part) in the B1 direction (first direction), and opens facing the D1 direction. Axis A1 is an axis extending in the D1 direction through the central region of the housing 5312, and the B1 direction is a specific radial direction centered on axis A1. In this example, for the sake of simplicity, an example is shown where the shape of the edge of the open end of the sound hole 121a is elliptical (the open end is elliptical). However, this does not limit the present invention. For example, the shape of the edge of the sound hole 121a may be a circle, square, triangle, or other shape. Also, the end of the sound hole 121a may be mesh-like. In other words, the end of the sound hole 121a may be composed of multiple holes. Also, in this example, for the sake of simplicity, we show an example in which one sound hole 121a is provided in region AR1 (first region) of the wall of the housing 5312. However, this does not limit the present invention. For example, two or more sound holes 121a may be provided in region AR1 (first region) of the wall of the housing 5312.

[0066] In this example, the sound hole 123a (second sound hole) is located in region AR3 of the wall portion 123 that is in contact with the region between region AR1 of the wall portion 5312 and region AR2 of the wall portion located on the D2 direction side of the driver unit 11 (the other side from which the acoustic signal AC2 is emitted). Furthermore, in this example, the sound hole 123a (second sound hole) is positioned biased toward the B2 direction (second direction). The B2 direction (second direction) is a direction that includes the opposite component of the B1 direction (first direction). Specific examples of such arrangement configurations are illustrated in the embodiments and their modifications described above. In addition, the sound pressure level of the acoustic signal AC2 emitted to the outside from the sound hole 123a is designed to be higher the further away the sound hole 121a is from the sound hole 123a. Specific examples of such arrangement configurations are also illustrated in the embodiments and their modifications described above.

[0067] <Support Department 5313> The support portion 5313 is a convex-shaped portion provided on the outer surface of the wall portion on the D1 direction side of the housing 5312. At least a portion of the outer surface area of ​​the support portion 5313 is convex. The outer surface area of ​​the support portion 5313 is the outer surface area surrounding the opening end 131b of the sound hole 121a (first sound hole). The outer surface area of ​​the support portion 5313 includes area 53131 (first area) and area 53132 (second area) which protrudes more than area 53131 (first area). Here, the outer surface area of ​​the support portion 5313 may be configured in a shape that guides the acoustic signal AC1 (first acoustic signal) emitted from the sound hole 121a (first sound hole) towards area 53131 (first area). In this example, the support portion 5313, which includes regions 53131 and 53132, is provided on the B1 direction side, while the support portion 5313 is not provided in region 5314 on the B2 direction side, which includes the opposite component.

[0068] <Wearing condition> The difference from the first embodiment is that when the acoustic signal output device 5300 is attached, the tip of the housing 5312 on the support portion 5313 side is inserted into the user's ear canal. When the tip of the housing 5312 is inserted into the ear canal, the region 5314 on the B2 direction side where the support portion 5313 is not provided comes into contact with the inside of the ear canal. Also, the region 53132 (second region) of the support portion comes into contact with the inside of the ear canal. On the other hand, the region 53131 (first region) of the support portion does not come into contact with the inside of the ear canal. Therefore, a gap is created between region 53131 and the inside of the ear canal, and the ear canal is not sealed. This has the advantage that the user can easily hear external sounds. Conversely, a portion of the acoustic signal AC1 emitted from the open end 131b of the sound hole 121a is emitted to the outside through the gap between region 53131 and the inside of the ear canal. The acoustic signal AC1 emitted to the outside in this manner is perceived as sound leakage, but as described in the first embodiment, this acoustic signal AC1 is canceled out by the acoustic signal AC2 emitted from the sound hole 123a, thereby suppressing sound leakage. Furthermore, since the sound hole 123a in this example is positioned biased toward the B2 direction, the acoustic signal AC2 emitted from the sound hole 123a is less likely to penetrate into the ear canal through the gap between region 53131 and the inside of the ear canal. Therefore, the acoustic signal AC1 is not canceled out to a great extent inside the ear canal, and the user can hear the acoustic signal AC1 with sufficient sound quality. A battery case for housing and charging the acoustic signal output device 5300 may be provided. In this case, it may be designed according to the convex shape provided on the support portion. For example, the area in which the convex shape is in contact when the acoustic signal output device 5300 is housed in the battery case may be designed to be deeper than the area in which other areas of the support portion are in contact. If the convex shape is made of a material that allows for shape modification, it may be designed to be, for example, smaller by a predetermined amount than the size including the convex shape, so that when the acoustic signal output device 5300 is housed in the battery case, the acoustic signal output device 5300 is held in the battery case by the convex shape.

[0069] <Example 4-2> In Example 4-1, a support portion 5313 is provided on the B1 direction side of the outer surface of the wall portion on the D1 direction side of the housing 5312, and no support portion is provided in the region 5314 on the B2 direction side, which includes the opposite component (Figure 30A). However, a protruding region surrounding the open end 131b of the sound hole 121a may be provided in this region 5314. This protruding region surrounding the open end 131b is, for example, an annular convex region surrounding the B2 direction side of the open end 131b. Preferably, when the acoustic signal output device 5300 is installed, most or all of this annular convex region surrounding the B2 direction side of the open end 131b is in contact with the inside of the ear canal, and it is desirable that the acoustic signal AC1 emitted from the open end 131b of the sound hole 121a does not leak out to the B2 direction side as much as possible.

[0070] <Example 4-3> Instead of providing the support portion 5313 in Example 4-1, a sound hole 53123b (for example, a through hole) may be provided on the outer surface of the wall portion on the D1 direction side of the housing 5312, as illustrated in the acoustic signal output device 5400 shown in Figures 31A to 31C. The sound hole 53123b takes in external sound into the ear canal and also releases the acoustic signal AC1 emitted into the housing 5312 to the outside. In this example, the sound hole 53123b is provided on the B1 direction side, and no sound hole 53123b is provided in the region 5314 on the B2 direction side, which includes the opposite direction component.

[0071] When the acoustic signal output device 5400 is attached, the tip of the housing 5312 is inserted into the ear canal, and the tip of the housing 5312 comes into contact with the inside of the ear canal. Also, the sound hole 53123b is located on the outside of the ear canal, so the ear canal is not sealed. This has the advantage that the user can easily hear external sounds. On the other hand, some of the acoustic signal AC1 emitted from the open end 131b of the sound hole 121a is emitted to the outside from the sound hole 53123b. This acoustic signal AC1 emitted to the outside is perceived as sound leakage, but as explained in the first embodiment, this acoustic signal AC1 is canceled out by the acoustic signal AC2 emitted from the sound hole 123a, thereby suppressing sound leakage. In addition, since the sound hole 123a in this example is positioned biased toward the B2 direction, the acoustic signal AC2 emitted from the sound hole 123a is less likely to penetrate into the inside of the ear canal from the sound hole 53123b. Therefore, the acoustic signal AC1 is not significantly canceled out within the ear canal, and the user can hear the acoustic signal AC1 with sufficient sound quality.

[0072] <Example 4-4> As illustrated in Figures 32A and 32B, the acoustic signal output device 5500 in this example has the aforementioned driver unit 11 and a housing 5512 (structural part) that houses the driver unit 11. The housing 5512 has an insertion part 5512a that is inserted into the ear canal when worn, and an external placement part 5512b that is positioned on any part of the auricle. The insertion part 5512a is provided with a through hole 55121 that penetrates the insertion part 5512a. As a result, even when the insertion part 5512a is inserted into the ear canal, the ear canal is open to the outside through the through hole 55121 and is not sealed. Although the external shape of the insertion part 5512a in Figures 32A and 32B is a donut shape with a through hole 55121, the external shape of the insertion part 5512a may be other shapes with a through hole 55121 (for example, a rectangular prism shape, a triangular prism shape, etc. with a through hole 55121). One or more sound holes 121a (first sound holes) are provided on one side of the insertion portion 5512a (the side inserted into the ear canal when worn: the D1 direction side). One or more sound holes 123a (second sound holes) are provided on the other side of the insertion portion 5512a (the D2 direction side). As described above, sound holes 121a release the acoustic signal AC1 emitted from the driver unit 11 to the outside, and sound holes 123a release the acoustic signal AC2 emitted from the driver unit 11 to the outside. Furthermore, the sound pressure level of the acoustic signal AC2 emitted from sound holes 123a may be designed to be higher the further away the sound holes 121a are from the space. Specific examples of such arrangement configurations are illustrated in the embodiments and their modifications described above.

[0073] When the acoustic signal output device 5500 is attached, the insertion portion 5512a of the housing 5512 is inserted into the ear canal, and the external placement portion 5512b is positioned on one of the parts of the auricle. The ear canal is not sealed by the through-hole 55121 of the insertion portion 5512a. This has the advantage that the user can easily hear external sounds. On the other hand, a portion of the acoustic signal AC1 emitted from the open end 131b of the sound hole 121a is emitted to the outside through the through-hole 55121. This acoustic signal AC1 emitted to the outside is perceived as sound leakage, but as explained in the first embodiment, this acoustic signal AC1 is canceled out by the acoustic signal AC2 emitted from the sound hole 123a, thereby suppressing sound leakage.

[0074] <Example 4-5> Any of Examples 4-1 to 4-4 may be combined with Design Examples 1 to 6 of the second embodiment. That is, in any of Examples 4-1 to 4-4, the resonance frequency of the hollow portion of the housing 5312, 5512 may be designed to be above a predetermined frequency (for example, above the frequency band in which human hearing is highly sensitive, for example, above 6kHz), and the acoustic signal AC2 (second acoustic signal) in which frequency band components including the predetermined frequency (for example, frequency band components in which human hearing is highly sensitive, for example, the 3kHz-6kHz frequency band component) are suppressed may be emitted to the outside from the sound hole 123a (second sound hole).

[0075] <Example 4-6> As illustrated in Figure 33, the structural part 5781 may be fixed to a curved rod-shaped mounting part 5782 that is shaped to be worn on the shoulder or neck of the user 1000. The structural part 5781 is, for example, one of the acoustic signal output devices 5300, 5400, or 5500 in Examples 4-1 to 4-5.

[0076] [Other variations] It should be noted that the present invention is not limited to the embodiments described above. For example, in each of the embodiments described above, the housing 12 and the support portion 13 were separate components, but the housing 12 and the support portion 13 may be integrally constructed.

[0077] In the first embodiment, the housing 12 does not necessarily have to have a sound hole 123a. Even in such a case, when the housing 12 and the support part 13 (structural part) are attached to the auricle 1010 of the user 1000, the region 132 (second region) of the support part 13 contacts and supports some part of the auricle 1010 (body), and the opening end 131b of the sound hole 121a (first sound hole) and the region 131 (first region) of the support part 13 do not contact at least a part of the auricle 1010 (body), and the region 131 (first region) is positioned on the external auditory canal 1011 side. In this case, the region 131 contacts the auricle 1010 and acts as support, so there is a high sense of stability when worn. Also, since the B2 direction side of the opening end 131b of the sound hole 121a is surrounded by the region 132, it is possible to suppress the leakage (sound leakage) of the acoustic signal AC1 emitted from the sound hole 121a to the B2 direction side. Furthermore, in the second embodiment, the support portion 13 may not be provided.

[0078] Furthermore, in each of the embodiments described above, the driver unit 11 was housed inside the housing 12. However, the driver unit 11 may be located outside the housing 12, and the acoustic signals AC1 and AC2 emitted from the driver unit 11 may be introduced into the housing 12 through a waveguide. [Explanation of Symbols]

[0079] 10,20,30,3100,4100,4200,5110,5120,5130,5140,5150,5160,5170,5190,5200-5600 Acoustic signal output device 5021,5111,5112,5121,5131,5151,5171,5191,5201,5781 Structural part 121a,123a sound hole 11 Driver Units 210 Switching section 220 Hollow part 241 Internal hollow part 1000 users 1010,1020 Auricle 1011,1021 External auditory canal

Claims

1. The structure includes one or more first sound holes for emitting a first acoustic signal to the outside, a hollow section for emitting a second acoustic signal into an internal space, and one or more second sound holes for emitting the second acoustic signal emitted into the internal space of the hollow section to the outside. The hollow section is designed to have a resonant frequency of 6 kHz or higher, and the second acoustic signal, in which frequency band components including 6 kHz are suppressed, is emitted to the outside from the second sound hole. The structural part includes an internal hollow part arranged in the internal space of the hollow part, An acoustic signal output device in which the internal space of the internal hollow portion is spatially separated from the internal space of the hollow portion located outside the internal hollow portion.

2. An acoustic signal output device according to claim 1, The device further comprises an electronic component for driving a driver unit that emits at least one of the first acoustic signal and the second acoustic signal. An acoustic signal output device in which at least a portion of the electronic component is housed in the internal space of the internal hollow portion.

3. An acoustic signal output device according to claim 1, The present invention further comprises a cushioning material disposed between the outer side of the internal hollow portion and the inner side of the hollow portion, An acoustic signal output device, the outer side of the internal hollow portion being fixed to the inner side of the hollow portion via the cushioning material.

4. An acoustic signal output device, The structure includes one or more first sound holes for emitting a first acoustic signal to the outside, a hollow section for emitting a second acoustic signal into an internal space, and one or more second sound holes for emitting the second acoustic signal emitted into the internal space of the hollow section to the outside. The hollow section is designed to have a resonant frequency of 6 kHz or higher, and the second acoustic signal, in which frequency band components including 6 kHz are suppressed, is emitted to the outside from the second sound hole. When the acoustic signal output device is fitted to the user, the first sound hole is positioned in a first direction, and the second sound hole is positioned in a second direction different from the first direction, with the first direction being the side of the user's ear canal. The structural part includes an internal hollow part arranged in the internal space of the hollow part, An acoustic signal output device in which the internal space of the internal hollow portion is spatially separated from the internal space of the hollow portion located outside the internal hollow portion.

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