Acoustic signal output device

Abstract

To provide an acoustic signal output device that does not seal an ear canal and is capable of reducing sound leakage to the surroundings.SOLUTION: An acoustic signal output device 30 includes a plurality of driver units, a first sound hole 121a-1 for leading out a first acoustic signal emitted from one of the driver units to an outside, a second sound hole 123a-1 for leading out a second acoustic signal, a third sound hole 123a-2 for leading out a third acoustic signal, and a fourth sound hole 121a-2 for leading out a fourth acoustic signal. The first sound hole is opened in a first direction. The second sound hole is opened in a second direction between the first direction and a direction opposite the first direction. The fourth sound hole is opened in a fourth direction which is the same as or approximate to the first direction. The third sound hole is opened in a third direction between the fourth direction and a direction opposite the fourth direction.SELECTED DRAWING: Figure 27

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 September 13, 2021], Internet<https: / / www.bose.com / en_us / better_with_bose / open-ear-headphones.html> [Overview of the project] [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] An acoustic signal output device is provided, comprising: a plurality of driver units; one or more first sound holes for leading out a first acoustic signal emitted from any of the driver units to the outside; one or more second sound holes for leading out a second acoustic signal emitted from any of the driver units to the outside; one or more third sound holes for leading out a third acoustic signal emitted from any of the driver units to the outside; and one or more fourth sound holes for leading out a fourth acoustic signal emitted from any of the driver units to the outside. The first sound holes open facing a first direction; the second sound holes open facing a second direction between the first direction and the opposite direction of the first direction; the fourth sound holes open facing a fourth direction that is the same as or approximate to the first direction; and the third sound holes open facing a third direction between the fourth direction and the opposite direction of the fourth direction. [Effects of the Invention]

[0007] This structure helps to suppress sound leakage to the surroundings. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a transparent perspective view illustrating the configuration of the acoustic signal output device according to the first embodiment. [Figure 2] Figure 2A is a transparent plan view illustrating the configuration of the acoustic signal output device according to the first embodiment. Figure 2B is a transparent front view illustrating the configuration of the acoustic signal output device according to the first embodiment. Figure 2C is a bottom view illustrating the configuration of the acoustic signal output device according to the first 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 3C is an end view of 2BC-2BC in Figure 2B. [Figure 4] Figure 4 is a conceptual diagram illustrating the arrangement of tone holes. [Figure 5] Figure 5A is a diagram illustrating the usage state of the acoustic signal output device of the first embodiment. Figure 5B is a diagram illustrating the observation conditions of the acoustic signal emitted from the acoustic signal output device of the first embodiment. [Figure 6]Figure 6 is a graph illustrating the frequency characteristics of the acoustic signal observed at position P1 in Figure 5B. [Figure 7] Figure 7 is a graph illustrating the frequency characteristics of the acoustic signal observed at position P2 in Figure 5B. [Figure 8] Figure 8 is a graph illustrating the difference between the acoustic signal observed at position P1 and the acoustic signal observed at position P2. [Figure 9] Figures 9A and 9B are graphs illustrating the relationship between the area ratio of tone holes and sound leakage. [Figure 10] Figure 10A is a front view illustrating the arrangement of the tone holes. Figure 10B is a conceptual diagram illustrating the arrangement of the tone holes. [Figure 11] Figure 11A is a front view illustrating the arrangement of the tone holes. Figure 11B is a conceptual diagram illustrating the arrangement of the tone holes. [Figure 12] Figures 12A to 12C are front views illustrating modified arrangements of the tone holes. [Figure 13] Figures 13A and 13B are transparent plan views illustrating variations in the arrangement of the tone holes. [Figure 14] Figures 14A and 14B are conceptual diagrams illustrating variations in the arrangement of tone holes. [Figure 15] Figure 15A is a transparent front view illustrating a modified arrangement of the sound holes. Figure 15B is an end view illustrating a modified arrangement of the sound holes and a modified spacing between the driver unit and the housing. [Figure 16] Figures 16A to 16C are end views illustrating modified examples of the acoustic signal output device of the first embodiment. [Figure 17] Figure 17 is a graph comparing the frequency characteristics of the acoustic signals observed at position P1 in Figure 5B. [Figure 18] Figure 18 is a graph illustrating the frequency characteristics of the acoustic signal observed at position P2 in Figure 5B. [Figure 19] Figure 19 is a graph illustrating the difference between the acoustic signal observed at position P1 and the acoustic signal observed at position P2. [Figure 20]Figure 20 is a transparent perspective view illustrating the configuration of the acoustic signal output device according to the second embodiment. [Figure 21] Figure 21A is a transparent plan view illustrating the configuration of the acoustic signal output device according to the second embodiment. Figure 21B is a transparent front view illustrating the configuration of the acoustic signal output device according to the first embodiment. Figure 21C is a bottom view illustrating the configuration of the acoustic signal output device according to the first embodiment. [Figure 22] Figure 22A is an end view of section 21A-21A in Figure 21B. Figure 22B is a cross-sectional view of section 21B-21B in Figure 21A. [Figure 23] Figures 23A and 23B illustrate the usage state of the acoustic signal output device according to the second embodiment. [Figure 24] Figure 24 is a transparent perspective view illustrating a modified example of the acoustic signal output device of the second embodiment. [Figure 25] Figure 25A is a transparent plan view illustrating a modified example of the acoustic signal output device of the second embodiment. Figure 25B is a transparent front view illustrating a modified example of the acoustic signal output device of the second embodiment. Figure 25C is a bottom view illustrating a modified example of the acoustic signal output device of the second embodiment. [Figure 26] Figure 26 is an end view of the 25A-25A section of Figure 25B. [Figure 27] Figure 27 is a perspective view illustrating the configuration of the acoustic signal output device according to the third embodiment. [Figure 28] Figure 28 is a transparent perspective view illustrating the configuration of the acoustic signal output device according to the third embodiment. [Figure 29] Figure 29 is a conceptual diagram illustrating the arrangement of tone holes. [Figure 30] Figures 30A to 30C are block diagrams illustrating the configuration of the circuit section. [Figure 31] Figure 31 is a diagram illustrating the usage state of the acoustic signal output device according to the third embodiment. [Figure 32] Figure 32A is a perspective view illustrating a modified example of the acoustic signal output device of the third embodiment. Figure 32B is a conceptual diagram illustrating a modified example of the arrangement of sound holes. [Figure 33]Figure 33A is a transparency perspective view illustrating a modified example of the acoustic signal output device of the third embodiment. Figure 33B is a diagram illustrating a modified example of the acoustic signal output device of the third embodiment. [Figure 34] Figure 34A is a diagram illustrating the configuration of the acoustic signal output device of the fourth embodiment. Figure 34B is a diagram illustrating a modified version of the acoustic signal output device of the fourth embodiment. [Figure 35] Figure 35A is a transparent front view illustrating the configuration of the acoustic signal output device according to the fifth embodiment. Figure 35B is a transparent plan view illustrating the configuration of the acoustic signal output device according to the fifth embodiment. Figure 35C is a transparent right side view illustrating the configuration of the acoustic signal output device according to the fifth embodiment. [Figure 36] Figure 36A is a plan view illustrating the fixing part of the fifth embodiment. Figure 36B is a right side view illustrating the fixing part of the fifth embodiment. Figure 36C is a front view illustrating the fixing part of the fifth embodiment. Figure 36D is a cross-sectional view taken along line 36A-36A of Figure 36A. [Figure 37] Figure 37A is a transparent front view illustrating a modified example of the acoustic signal output device of the fifth embodiment. Figure 37B is a transparent plan view illustrating a modified example of the acoustic signal output device of the fifth embodiment. Figure 37C is a transparent right side view illustrating a modified example of the acoustic signal output device of the fifth embodiment. [Figure 38] Figure 38 is a front view illustrating a modified example of the acoustic signal output device of the fifth embodiment. [Figure 39] Figures 39A and 39B are front views illustrating modified examples of the acoustic signal output device of the fifth embodiment. [Figure 40] Figure 40A is a plan view illustrating a modified example of the acoustic signal output device of the fifth embodiment. Figure 40B is a conceptual diagram illustrating a modified example of the arrangement of sound holes. [Figure 41] Figure 41A is a plan view illustrating a modified example of the acoustic signal output device of the fifth embodiment. Figure 41B is a conceptual diagram illustrating a modified example of the arrangement of sound holes. [Figure 42]Figure 42 is a transparent front view illustrating the configuration of the acoustic signal output device according to the fifth embodiment. [Figure 43] Figure 43A is a rear view illustrating the configuration of the acoustic signal output device according to the fifth embodiment. Figure 43B is a cross-sectional view taken along line 43A-43A in Figure 43A. [Figure 44] Figure 44 is a transparent front view illustrating a modified example of the acoustic signal output device of the fifth embodiment. [Figure 45] Figure 45 is a transparent front view illustrating a modified example of the acoustic signal output device of the fifth embodiment. [Figure 46] Figure 46A is a transparent front view illustrating a modified example of the acoustic signal output device of the fifth embodiment. Figure 46B is a transparent bottom view illustrating a modified example of the acoustic signal output device of the fifth embodiment. Figure 46C is a plan view illustrating a modified example of the acoustic signal output device of the fifth embodiment. [Figure 47] Figures 47A and 47B are conceptual diagrams illustrating variations in the arrangement of the tone holes. [Figure 48] Figures 48A and 48B are conceptual diagrams illustrating modified arrangements of tone holes. [Figure 49] Figure 49A is a front view illustrating a modified example of the acoustic signal output device of the sixth embodiment. Figure 49B is a perspective view illustrating a modified example of the acoustic signal output device of the sixth embodiment. [Figure 50] Figure 50A is a perspective view illustrating a modified example of the acoustic signal output device of the sixth embodiment. Figure 50B is a plan view illustrating a modified example of the acoustic signal output device of the sixth embodiment. [Figure 51] Figure 51A is a plan view illustrating a modified example of the acoustic signal output device of the sixth embodiment. Figure 51B is a plan view illustrating a modified example of the acoustic signal output device of the sixth embodiment. [Figure 52] Figure 52A is a plan view illustrating a modified example of the acoustic signal output device of the sixth embodiment. Figure 52B is a transparency perspective view illustrating a modified example of the acoustic signal output device of the sixth embodiment. [Figure 53]Figure 53A is a plan view illustrating a modified example of the acoustic signal output device of the sixth embodiment. Figure 53B is a right side view illustrating a modified example of the acoustic signal output device of the sixth embodiment. Figure 53C is a front view illustrating a modified example of the acoustic signal output device of the sixth embodiment. Figure 53D is a rear view illustrating a modified example of the acoustic signal output device of the sixth embodiment. Figure 53E is a front view illustrating the usage state of the modified example of the acoustic signal output device of the sixth embodiment. [Figure 54] Figure 54A is a perspective view illustrating a modified example of the acoustic signal output device of the sixth embodiment. Figure 54B is a perspective view illustrating a modified example of the acoustic signal output device of the sixth embodiment. Figure 54C is a perspective view illustrating the usage state of the modified example of the acoustic signal output device of the sixth embodiment. [Figure 55] Figures 55A and 55B are front views illustrating the usage of a modified example of the acoustic signal output device of the sixth embodiment. [Figure 56] Figure 56A is a front view illustrating a modified example of the acoustic signal output device of the sixth embodiment. Figure 56B is a rear view illustrating a modified example of the acoustic signal output device of the sixth embodiment. Figure 56C is a front view illustrating the usage state of the modified example of the acoustic signal output device of the sixth embodiment. [Figure 57] Figure 57A is a plan view illustrating a modified example of the acoustic signal output device of the sixth embodiment. Figure 57B is a right side view illustrating a modified example of the acoustic signal output device of the sixth embodiment. Figure 57C is a front view illustrating a modified example of the acoustic signal output device of the sixth embodiment. Figure 57D is a rear view illustrating a modified example of the acoustic signal output device of the sixth embodiment. Figure 57E is a front view illustrating the usage state of the modified example of the acoustic signal output device of the sixth embodiment. [Figure 58]Figure 58A is a plan view illustrating a modified example of the acoustic signal output device of the sixth embodiment. Figure 58B is a front view illustrating a modified example of the acoustic signal output device of the sixth embodiment. Figure 58C is a rear view illustrating a modified example of the acoustic signal output device of the sixth embodiment. Figure 58D is a front view illustrating the usage state of the modified example of the acoustic signal output device of the sixth embodiment. [Figure 59] Figure 59A is a plan view illustrating a modified example of the acoustic signal output device of the sixth embodiment. Figure 59B is a front view illustrating a modified example of the acoustic signal output device of the sixth embodiment. Figure 59C is a rear view illustrating a modified example of the acoustic signal output device of the sixth embodiment. Figure 59D is a front view illustrating the usage state of the modified example of the acoustic signal output device of the sixth embodiment. [Figure 60] Figure 60A is a left side view illustrating a modified example of the acoustic signal output device of the sixth embodiment. Figure 60B is a front view illustrating a modified example of the acoustic signal output device of the sixth embodiment. Figure 60C is a front view illustrating the usage state of the modified example of the acoustic signal output device of the sixth embodiment. [Figure 61] Figure 61A is a plan view illustrating a modified example of the acoustic signal output device of the sixth embodiment. Figure 61B is a right side view illustrating a modified example of the acoustic signal output device of the sixth embodiment. Figure 61C is a front view illustrating a modified example of the acoustic signal output device of the sixth embodiment. Figure 61D is a rear view illustrating a modified example of the acoustic signal output device of the sixth embodiment. Figure 61E is a front view illustrating the usage state of the modified example of the acoustic signal output device of the sixth embodiment. [Figure 62] Figures 62A and 62B are conceptual diagrams illustrating modified examples of the acoustic signal output device of the sixth embodiment. [Figure 63] Figures 63A and 63B are conceptual diagrams illustrating modified examples of the acoustic signal output device of the sixth embodiment. [Figure 64] Figures 64A and 64B are conceptual diagrams illustrating modified examples of the acoustic signal output device of the sixth embodiment. [Figure 65]Figures 65A to 65C are conceptual diagrams illustrating modified examples of the acoustic signal output device of the sixth embodiment. [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described below with reference to the drawings. [First Embodiment] First, a first embodiment of the present invention will be described. <Structure> 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 to 2C, and 3A to 3C, the acoustic signal output device 10 of this embodiment has 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, and a housing 12 that houses the driver unit 11 inside.

[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 opposite phase signal (phase inverted signal) of the acoustic signal AC1 or an approximate signal of the opposite 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). For example, the driver unit 11 includes a diaphragm 113 that emits the acoustic signal AC1 from one surface 113a to the D1 direction by vibration, and emits the acoustic signal AC2 from the other surface 113b to the D2 direction by this vibration (Figure 2B). In this example, the driver unit 11 vibrates its diaphragm 113 based on the input output signal, emitting acoustic signal AC1 from one side surface 111 toward the D1 direction, and emitting acoustic signal AC2, which is either the inverse phase signal of acoustic signal AC1 or an approximate signal of the inverse phase signal, from the other side surface 112 toward the D2 direction. In other words, acoustic signal AC2 is emitted secondarily along with the emission of 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 exactly 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 (D1 direction) and the other side (D2 direction) depends on the type and shape of the driver unit 11. Also, depending on the type and shape of the driver unit 11, acoustic signal AC2 may be exactly the inverse phase signal of acoustic signal AC1, or it may be an approximate signal of the inverse phase signal of 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 inverse phase signal of the acoustic signal AC1 and its approximate signal is preferably less than or equal to δ1% of one period of the inverse phase signal of the acoustic signal AC1. Examples of δ1% include 1%, 3%, 5%, 10%, and 20%. Furthermore, the difference between the amplitude of the inverse phase signal of the acoustic signal AC1 and the amplitude of its approximate signal is preferably less than or equal to δ2% of the amplitude of the inverse phase signal of the acoustic signal AC1. Examples of δ2% include 1%, 3%, 5%, 10%, and 20%. Examples of the driver unit 11 type include dynamic, balanced armature, hybrid dynamic and balanced armature, and condenser. There are no limitations on the shape of the driver unit 11 or the diaphragm 113. In this embodiment, for the sake of simplicity, an example is shown in which the driver unit 11 has a substantially cylindrical shape with both end faces and the diaphragm 113 has a substantially disc shape, but this does not limit the present invention. For example, the driver unit 11 may have a rectangular parallelepiped shape, or the diaphragm 113 may have a dome shape. Examples of acoustic signals include sounds such as music, voices, sound effects, and ambient sounds.

[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. There are no limitations on the shape of the housing 12, but it is desirable that the shape of the housing 12 be rotationally symmetric (line symmetric) or substantially rotationally symmetric about an axis A1 extending along the D1 direction. This makes it easier to provide sound holes 123a (details described later) in such a way that the variation in the direction of sound energy emitted from the housing 12 is reduced. As a result, it becomes easier to reduce sound leakage uniformly in each direction. For example, the housing 12 has a first end face which is a wall portion 121 located on one side (D1 direction side) of the driver unit 11, a second end face which is a wall portion 122 located on the other side (D2 direction side) of the driver unit 11, and a side surface which is a wall portion 123 that surrounds the space sandwiched between the first and second end faces, centered on the axis A1 passing through the first and second end faces (Figures 2B and 3B). In this embodiment, for the sake of simplicity, an example is shown in which the housing 12 has a substantially cylindrical shape with both end faces. For example, the distance between the wall portion 121 and the wall portion 122 is 10 mm, and the wall portions 121 and 122 are circular with a radius of 10 mm. However, these are just examples and do not limit the present invention. For example, the housing 12 may have a substantially dome shape with walls at its ends, or it may be a hollow substantially cubic shape, or it may be 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 guiding 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 guiding 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 guided to the outside, respectively.

[0013] The acoustic signal AC1 emitted from sound hole 121a reaches the user's ear canal and is heard by the user. On the other hand, an 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 sound hole 123a. A portion of this acoustic signal AC2 cancels out a portion of the acoustic signal AC1 emitted from sound hole 121a (sound leakage component). In other words, the attenuation rate η of the acoustic signal AC1 (first acoustic signal) at position P2 (second position) relative to position P1 (first position) is determined by the emission of acoustic signal AC1 (first acoustic signal) from sound hole 121a (first sound hole) and acoustic signal AC2 (second acoustic signal) from sound hole 123a (second sound hole). 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 th The above can be achieved. Here, position P1 (first point) is a predetermined point to which the acoustic signal AC1 (first acoustic signal) emitted from the sound hole 121a (first sound hole) reaches. On the other hand, position P2 (second point) is a predetermined point that is further from the acoustic signal output device 10 than position P1 (first point). The predetermined value η th This is the attenuation rate η of an arbitrary or specific acoustic signal (sound) due to air propagation at position P2 (second point) relative to position P1 (first point). 21 It is a value smaller than (lower than) ω. this the attenuation amount η due to air propagation of an arbitrary or specific acoustic signal (sound) at position P2 (second point) with respect to position P1 (first point). 22 is a value larger than that. That is, the acoustic signal output device 10 of the present embodiment has an attenuation rate η 11 which is smaller than the attenuation rate η 21 and is designed to be less than or equal to a predetermined value η th or the attenuation amount η 12 is designed to be greater than or equal to a predetermined value ω 22 which is larger than the attenuation amount η th Note that the acoustic signal AC1 is air-propagated from position P1 to position P, 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 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 position P1. Also, the attenuation amount η 12 is the difference (|AMP1(AC1) - AMP2(AC1)|) between the magnitude AMP1(AC1) and the magnitude AMP2(AC1). 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 position P1 to position P2 attenuates due to air propagation without being caused by the acoustic signal AC2. The attenuation rate η 21 is the ratio (AMP2(AC ar ) / AMP1(AC ar )) of the magnitude AMP2(AC ar ) of the acoustic signal AC at position P2, which has attenuated due to air propagation (without being caused by the acoustic signal AC2), to the magnitude AMP1(AC ar ) of the acoustic signal AC at position P1. Also, the attenuation amount η ar is the difference (|AMP1(AC ar ) - AMP2(AC 22 )) between the magnitude AMP1(AC ar ) and the magnitude AMP2(AC ar ). 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 wearing the acoustic signal output device 10 (for example, a person other than the user 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.

[0014] An example of the arrangement of tone holes 121a and 123a is shown. 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 D1 direction side from which the acoustic signal AC1 is emitted) (Figures 1, 2A, 2B, and 3B). That is, the sound hole 121a opens facing the D1 direction (first direction) along the axis A1. In addition, the sound hole 123a (second sound hole) in this embodiment is provided in region AR3 of the wall portion 123 that is in contact with region AR between region AR1 (first region) of the wall portion 121 of the housing 12 and region AR2 (second region) of the wall portion 122 located on the D2 direction side of the driver unit 11 (the other side from which the acoustic signal AC2 is emitted). In other words, if we take the center of the housing 12 as the reference point, and define the direction between the D1 direction (first direction) and the opposite direction of the D1 direction as the D12 direction (second direction) (Figure 3B), then the sound hole 121a (first sound hole) is located on the D1 direction side (first direction side) of the housing 12, and the sound hole 123a (second sound hole) is located on the D12 direction side (second direction side) of the housing 12. For example, if the housing 12 has a first end face which is a wall portion 121 located on one side (D1 direction side) of the driver unit 11, a second end face which is a wall portion 122 located on the other side (D2 direction side) of the driver unit 11, and a side surface which is a wall portion 123 that surrounds the space between the first and second end faces, centering on an axis A1 along the emission direction (D1 direction) of the acoustic signal AC1 passing through the first and second end faces (Figures 2B and 3B), then the sound hole 121a (first sound hole) is provided on the first end face, and the sound hole 123a (second sound hole) is provided on the side surface. In this embodiment, no sound holes are provided on the wall portion 122 side of the housing 12. 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 that excess will be perceived as sound leakage.

[0015] As illustrated in Figure 2A, the sound hole 121a in this embodiment is positioned on or near the axis A1 along the emission direction (D1 direction) of the acoustic signal AC1. The axis A1 in this embodiment passes through the center or near the center of the region AR1 (first region) of the wall portion 121 located on one side (D1 direction side) of the driver unit 11 of the housing 12. For example, axis A1 is an axis that extends in the D1 direction through the central region of the housing 12. That is, the sound hole 121a in this embodiment is provided at the central position of region AR1 of the wall portion 121 of the housing 12. In this embodiment, for the sake of simplicity of explanation, an example is shown in which the shape of the edge of the open end of the sound hole 121a is circular (the open end is round). The radius of such a sound hole 121a is, for example, 3.5 mm. However, this does not limit the present invention. For example, the shape of the edge of the open end of the sound hole 121a may be an ellipse, a square, a triangle, or other shape. Furthermore, the open end of the sound hole 121a may be mesh-like. In other words, the open end of the sound hole 121a may be composed of multiple holes. Also, in this embodiment, for the sake of simplicity of explanation, 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.

[0016] In this embodiment, the tone hole 123a (second tone hole) is preferably arranged in a manner that takes into consideration the following points, for example. (1) Positional considerations: The sound hole 123a is positioned such that the propagation path of the acoustic signal AC2 emitted from the sound hole 123a overlaps with the propagation path of the sound leakage component of the acoustic signal AC1 that is to be canceled out. (2) From the perspective of area: Depending on the opening area of ​​the sound hole 123a, the propagation region of the acoustic signal AC2 emitted from the sound hole 123a and the frequency characteristics of the housing 12 will differ. In addition, the frequency characteristics of the housing 12 will affect the frequency characteristics of the acoustic signal AC2 emitted from the sound hole 123a, i.e., the amplitude at each frequency. Considering the propagation region and frequency characteristics of the acoustic signal AC2 emitted from the sound hole 123a, the opening area of ​​the sound hole 123a is determined such that in the region where sound leakage components are to be canceled out, the sound leakage components are canceled out by the acoustic signal AC2 emitted from the sound hole 123a. From the above perspective, for example, the tone hole 123a (second tone hole) is preferably configured as follows. For example, as illustrated in Figures 2B, 3A, and 3C, it is desirable that multiple sound holes 123a (second sound holes) in this embodiment are provided along a circumference (circle) C1 centered on axis A1, which is in the direction of emission of the acoustic signal AC1 (first acoustic signal). When multiple sound holes 123a are provided along the circumference C1, the acoustic signal AC2 is emitted radially (radially from axis A1) from the sound holes 123a to the outside. Here, the sound leakage component of the acoustic signal AC1 is also emitted radially (radially from axis A1) from the sound holes 121a to the outside. Therefore, by providing multiple sound holes 123a along the circumference C1, the sound leakage component of the acoustic signal AC1 can be appropriately canceled out by the acoustic signal AC2. In this embodiment, for the sake of simplicity of explanation, an example is shown in which multiple sound holes 123a are provided on the circumference C1. However, the multiple tone holes 123a only need to be arranged along the circumference C1, and it is not necessarily required that all tone holes 123a be precisely positioned on the circumference C1.

[0017] Preferably, when the circumference C1 is divided into a plurality of unit arc regions, the sum of the opening areas of the tone holes 123a (second tone holes) provided along the first arc region, which is one of the unit arc regions, is the same as or approximately the same as the sum of the opening areas of the tone holes 123a (second tone holes) provided along the second arc region, which is one of the unit arc regions excluding the first arc region. For example, as illustrated in Figure 4, when the circumference C1 is divided equally into four unit arc regions C1-1, ..., C1-4, the sum of the opening areas of the tone holes 123a (second tone holes) located along the first arc region (e.g., unit arc region C1-1), which is one of the unit arc regions C1-1, ..., C1-4, is the same as or approximately the same as the sum of the opening areas of the tone holes 123a (second tone holes) located along the second arc region (e.g., unit arc region C1-2), which is one of the unit arc regions excluding the first arc region. Note that, for the sake of simplicity, an example in which the circumference C1 is divided equally into four unit arc regions C1-1, ..., C1-4 is shown here, but this does not limit the present invention. Furthermore, "α1 and α2 are approximately the same" means that the difference between α1 and α2 is less than or equal to β% of α1. Examples of β% include 3%, 5%, 10%, etc. As a result, the sound pressure distribution of the acoustic signal AC2 emitted from the sound holes 123a located along the first arc region and the sound pressure distribution of the acoustic signal AC2 emitted from the sound holes 123a located along the second arc region are point-symmetric or approximately point-symmetric with respect to axis A1. Preferably, the sum of the opening areas of the sound holes 123a (second sound holes) located along each unit arc region is the same or approximately the same for all unit arc regions. As a result, the sound pressure distribution of the acoustic signal AC2 emitted from the sound holes 123a is point-symmetric or approximately point-symmetric with respect to axis A1. This allows the sound leakage component of the acoustic signal AC1 to be more appropriately canceled out by the acoustic signal AC2.

[0018] More preferably, the multiple sound holes 123a are provided along the circumference C1 with the same shape, size, and spacing. For example, multiple sound holes 123a with a width of 4 mm and a height of 3.5 mm are provided along the circumference C1 with the same shape, size, and spacing. When multiple sound holes 123a are provided along the circumference C1 with the same shape, size, and spacing, the sound leakage component of the sound signal AC1 can be more effectively canceled out by the sound signal AC2. However, this does not limit the present invention.

[0019] Preferably, the sound hole 123a (second sound hole) is provided in the wall portion that is in contact with region AR located on the other side (D2 direction side) of the driver unit 11 (Figure 3B). This allows the direct wave of the acoustic signal AC2 emitted from the other side of the driver unit 11 to be efficiently guided out through the sound hole 123a. As a result, the sound leakage component of the acoustic signal AC1 can be more appropriately canceled out by the acoustic signal AC2.

[0020] In this embodiment, for the sake of simplicity, we will illustrate the case where the edge of the open end of the tone hole 123a is square (i.e., the open end is rectangular), but this does not limit the present invention. For example, the edge of the open end of the tone hole 123a may be a circle, an ellipse, a triangle, or any other shape. Also, the open end of the tone hole 123a may be mesh-like. In other words, the open end of the tone hole 123a may be composed of multiple holes. Furthermore, there is no limit to the number of tone holes 123a; a single tone hole 123a may be provided in the region AR3 of the wall portion 123 of the housing 12, or multiple tone holes 123a may be provided.

[0021] The ratio S2 / S1 of the total opening area S2 of tone holes 123a (second tone hole) to the total opening area S1 of tone holes 121a (first tone hole) is desirable to satisfy 2 / 3 ≤ S2 / S1 ≤ 4 (details will be described later). This allows the sound leakage component of acoustic signal AC1 to be appropriately canceled out by acoustic signal AC2.

[0022] The sound leakage suppression performance may also depend on the ratio of the area of ​​the wall portion 123 where the sound hole 123a is provided to the opening area of ​​the sound hole 123a. For example, consider a case where the housing 12 has a first end face which is a wall portion 121 located on one side (D1 direction side) of the driver unit 11, a second end face which is a wall portion 122 located on the other side (D2 direction side) of the driver unit 11, and a side surface which is a wall portion 123 that surrounds the space between the first and second end faces, centered on an axis A1 along the emission direction (D1 direction) of the acoustic signal AC1 passing through the first and second end faces, with a sound hole 121a (first sound hole) provided on the first end face and a sound hole 123a (second sound hole) provided on the side surface (Figures 2B, 3B). In such cases, the ratio S2 / S3 of the sum of the opening areas of the sound holes 123a to the total surface area S3 of the side is preferably 1 / 20 ≤ S2 / S3 ≤ 1 / 5 (details will be described later). This allows the sound leakage component of the acoustic signal AC1 to be appropriately canceled out by the acoustic signal AC2. However, this does not limit the present invention.

[0023] <Usage Status> Figure 5A illustrates the usage of the acoustic signal output device 10. In the example in Figure 5A, one acoustic signal output device 10 is attached to the right ear 1010 and one to the left ear 1020 of user 1000. Any attachment mechanism can be used to attach the acoustic signal output device 10 to the ears. Each acoustic signal output device 10 is 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 to the D1 direction side and acoustic signal AC2 to the other side. Acoustic signal AC1 is emitted from the sound hole 121a, and the emitted acoustic signal AC1 enters the right ear 1010 and the left ear 1020 and is heard by 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 the acoustic signal AC1 (sound leakage component) emitted from the sound hole 121a.

[0024] <Experimental Results> This section presents experimental results demonstrating the sound leakage suppression effect of the acoustic signal output device 10 of this embodiment. In this experiment, as shown in Figure 5B, the acoustic signal output devices 10 were attached to both ears of a dummy head 1100 that mimicked a human head, and acoustic signals were observed at positions P1 and P2. In this example, position P1 is near the left ear 1120 of the dummy head 1100 (near the acoustic signal output device 10), and position P2 is 15 cm away from position P1.

[0025] Figure 6 illustrates the frequency characteristics of the acoustic signal observed at position P1 in Figure 5B, Figure 7 illustrates the frequency characteristics of the acoustic signal observed at position P2 in Figure 5B, and Figure 8 illustrates the difference (difference in sound pressure level for each frequency) between the frequency characteristics of the acoustic signal observed at position P1 and the frequency characteristics of the acoustic signal observed at position P2. The horizontal axis represents frequency (Frequency [Hz]), and the vertical axis represents sound pressure level (SPL [dB]). The solid line graph illustrates the frequency characteristics when using the acoustic signal output device 10 of this embodiment, and the dashed line graph illustrates the frequency characteristics when using a conventional acoustic signal output device (open-ear type earphone). As illustrated in Figure 8, it can be seen that when using the acoustic signal output device 10 of this embodiment, the difference between the sound pressure of the acoustic signal observed at position P1 and the sound pressure of the acoustic signal observed at position P2 is larger compared to when using a conventional acoustic signal output device. This indicates that the acoustic signal output device 10 of this embodiment is able to suppress sound leakage at position P2 compared to conventional acoustic signal output devices.

[0026] Figure 9A illustrates the relationship between the ratio S2 / S1 of the total opening area S2 of the tone holes 123a (second tone hole) to the total opening area S1 of the tone holes 121a (first tone hole), and the difference between the frequency characteristics of the acoustic signal observed at position P1 and the frequency characteristics of the acoustic signal observed at position P2. The horizontal axis shows the ratio S2 / S1, and the vertical axis shows the sound pressure level (SPL) [dB] representing the difference. r12h6 illustrates the results when there are 6 tone holes 121a and 4 tone holes 123a, r12h12 illustrates the results when there are 12 tone holes 121a and 4 tone holes 123a, and r45h35 illustrates the results when there is 1 tone hole 121a and 4 tone holes 123a. As illustrated in Figure 9A, the ratio S2 / S1 of the total opening area S2 of sound holes 123a to the total opening area S1 of sound holes 121a is in the range of 2 / 3 ≤ S2 / S1 ≤ 4, and in particular, the difference between the sound pressure of the acoustic signal observed at position P1 and the sound pressure of the acoustic signal observed at position P2 is large. This indicates that the sound leakage suppression effect is large in this range. Figure 9B illustrates the relationship between the ratio S2 / S3 of the total opening area S2 of the sound holes 123a (second sound holes) to the total side surface area S3, and the difference between the frequency characteristics of the acoustic signal observed at position P1 and the frequency characteristics of the acoustic signal observed at position P2. The horizontal axis shows the ratio S2 / S3, and the vertical axis shows the sound pressure level (SPL) [dB] representing the difference. The meanings of r12h6, r12h12, and r45h35 are the same as in Figure 9A. As illustrated in Figure 9B, it can be seen that the difference between the sound pressure of the acoustic signal observed at position P1 and the sound pressure of the acoustic signal observed at position P2 is particularly large when the ratio S2 / S3 of the total opening area S2 of the sound holes 123a (second sound holes) to the total side surface area S3 is in the range of 1 / 20 ≤ S2 / S3 ≤ 1 / 5. This indicates that the sound leakage suppression effect is large in this range.

[0027] [Modification 1 of the First Embodiment] In the first embodiment, an example was shown in which multiple tone holes 123a (second tone holes) of the same shape, size, and spacing are provided along the circumference C1. However, this does not limit the present invention. Multiple tone holes 123a of different shapes and / or sizes and / or spacings may be provided along the circumference C1. For example, as illustrated in Figures 10A, 10B, 11A, 11B, and 12A, multiple tone holes 123a of different shapes and spacings may be provided in the wall portion 123 along the circumference C1, as illustrated in Figure 12B, multiple tone holes 123a of different spacings may be provided in the wall portion 123 along the circumference C1, as illustrated in Figure 12C, and multiple tone holes 123a of different shapes and sizes may be provided in the wall portion 123 along the circumference C1.

[0028] Furthermore, even in such cases, when the circumference C1 is divided into multiple unit arc regions, it is preferable that the sum of the opening areas of the tone holes 123a (second tone holes) provided along the first arc region, which is one of the unit arc regions, is the same as or approximately the same as the sum of the opening areas of the tone holes 123a provided along the second arc region, which is one of the unit arc regions excluding the first arc region. More preferably, it is desirable that the sum of the opening areas of the tone holes 123a provided along each unit arc region is the same or approximately the same for all of them. For example, as illustrated in Figures 10A, 10B, 11A, and 11B, the number and size of the tone holes 123a provided in each unit arc region C1-1, C1-2, C1-3, and C1-4 are different from each other. However, it is desirable that the sum of the opening areas of the tone holes 123a provided in unit arc region C1-1, the sum of the opening areas of the tone holes 123a provided in unit arc region C1-2, the sum of the opening areas of the tone holes 123a provided in unit arc region C1-3, and the sum of the opening areas of the tone holes 123a provided in unit arc region C1-4 are all the same or approximately the same.

[0029] It is sufficient that multiple tone holes 123a are aligned along the circumference C1, and not all tone holes 123a are necessarily positioned precisely on the circumference C1. For example, as shown in Figures 12A, 12B, and 12C, not all tone holes 123a are necessarily positioned on the circumference C1; it is sufficient that these multiple tone holes 123a are arranged along the circumference C1. Note that the position of the circumference C1 is not limited to that exemplified in the first embodiment, and any circumference centered on axis A1 is acceptable.

[0030] Furthermore, if sufficient sound leakage suppression can be obtained, not all sound holes 123a are required to be arranged along the circumference C1. In other words, some sound holes 123a may be located outside the circumference C1. Also, if sufficient sound leakage suppression can be obtained, there is no limit to the number of sound holes 123a, and even one sound hole 123a may be provided.

[0031] [Modification 2 of the First Embodiment] In the first embodiment, a configuration was illustrated in which one sound hole 121a is located at the central position (hereinafter simply referred to as the "central position") of region AR1 (the region of the wall portion located on one side of the driver unit) of the wall portion 121 of the housing 12. However, multiple sound holes 121a may be provided in region AR1 of the wall portion 121 of the housing 12, or the sound holes 121a may be biased to an eccentric position offset from the center (central position) of region AR1 of the wall portion 121 of the housing 12. For example, as illustrated in Figure 13A, one sound hole 121a may be provided at an eccentric position on region AR1 (a position on axis A12 that is offset from axis A1 and parallel to axis A1) (hereinafter simply referred to as the "eccentric position"). In other words, the position of one sound hole 121a provided in region AR1 may be biased to an eccentric position. Alternatively, as illustrated in Figure 13B, multiple sound holes 121a may be provided in region AR1, and these multiple sound holes 121a may be offset from axis A1 and located at eccentric positions on axis A12 parallel to axis A1. In other words, the positions of the multiple sound holes 121a provided in region AR1 may be offset to eccentric positions. That is, there may be one sound hole 121a or multiple sound holes 121a, and the sound holes 121a may be offset to the center of region AR1 on the wall portion 121 of the housing 12, or to eccentric positions. There is no limit to the distance between axis A1 and axis A12, and it should be set according to the required sound leakage suppression performance. An example of the distance between axis A1 and axis A12 is 4 mm, but this does not limit the present invention.

[0032] The resonant frequency of the housing 12 can be controlled by the arrangement of the sound holes 121a provided in region AR1 (for example, the number, size, spacing, and arrangement of the sound holes 121a). The resonant frequency of the housing 12 affects the frequency characteristics of the acoustic signals emitted from the sound holes 121a and 123a. Therefore, the frequency characteristics of the acoustic signals emitted from the sound holes 121a and 123a can be controlled by the arrangement of the sound holes 121a provided in region AR1. For example, as the frequencies of acoustic signals AC1 and AC2 increase, their wavelengths become shorter, making it difficult to phase-align them so that the sound leakage component of acoustic signal AC1 emitted to the outside is canceled out by acoustic signal AC2. As a result, the higher the frequencies of acoustic signals AC1 and AC2, the more difficult it becomes to suppress sound leakage of acoustic signal AC1. At the resonant frequency of the housing 12, the sound pressure levels of acoustic signals AC1 and AC2 increase, so if the resonant frequency of the housing 12 falls within a high-frequency band where sound leakage suppression is difficult, the sound leakage will be perceived as significant. To solve this problem, the arrangement of the sound holes 121a may be set as in the following examples 2-1 and 2, and the resonant frequency of the housing 12 may be controlled.

[0033] <Example 2-1> In high-frequency ranges where sound leakage is difficult to suppress, the arrangement of the sound holes 121a may be set so that human auditory sensitivity to the resonant frequency of the housing 12 is reduced. For example, a predetermined frequency f of the housing 12 where the position of the sound holes 121a is biased to a certain eccentric position. th S represents the human auditory sensitivity (ease of hearing) to acoustic signals at the above resonant frequencies. d Furthermore, the predetermined frequency f of the housing 12, in which the sound hole 121a is located at the central position. th The human auditory sensitivity to acoustic signals at the above resonant frequencies is defined as S. c Let's assume that the auditory sensitivity S in this case is... d auditory sensitivity S c It is assumed to be lower than that. In other words, the predetermined frequency f of the housing 12 is such that the position of the sound hole 121a (first sound hole) is biased to a certain eccentric position (a position offset from the center of the wall region located on one side of the driver unit). th Human auditory sensitivity S to acoustic signals at the above resonant frequencies dThis is the predetermined frequency f of the housing 12, assuming that the sound hole 121a is located in the central position (center of the wall area on one side of the driver unit). th Human auditory sensitivity S to acoustic signals at the above resonant frequencies c It is lower than this. The position of the sound hole 121a may be shifted to such an eccentric position. Note that auditory sensitivity can be any indicator that represents how easily a sound is heard. The higher the auditory sensitivity, the easier it is to hear. An example of auditory sensitivity is the reciprocal of the sound pressure level required for a person to perceive a sound of a standard loudness. For example, auditory sensitivity is the reciprocal of the sound pressure level at each frequency in the equal loudness curves. A predetermined frequency f th This refers to the lower limit of the frequency band that includes the frequency at which it becomes difficult to cancel out the sound leakage component of acoustic signal AC1 with acoustic signal AC2. (Determined frequency f) th Examples include 3000Hz, 4000Hz, 5000Hz, and 6000Hz.

[0034] <Example 2-2> Depending on the arrangement of the sound holes 121a, the resonance peak of the magnitude of the acoustic signal AC1 and / or acoustic signal AC2 emitted from the housing 12 may be distorted. For example, the predetermined frequency f of the magnitude of the acoustic signal AC1 emitted from the sound holes 121a and / or acoustic signal AC2 emitted from the sound holes 123a of the housing 12 in which the position of the sound holes 121a is biased to a certain eccentric position th The sharpness (point of sharpness) of the peak in the above is Q. d Furthermore, the magnitude of the acoustic signal AC1 emitted from the sound hole 121a of the housing 12, which has the sound hole 121a located in the central position, and / or the acoustic signal AC2 emitted from the sound hole 123a, is a predetermined frequency f. th The sharpness of the peak above is Q c Let's assume the peak sharpness Q is as follows. d Q is the sharpness of the peak. c It is assumed to be duller than that. That is, the predetermined frequency f of the magnitude of the acoustic signal AC1 (first acoustic signal) emitted from the acoustic signal AC2 (secondth Peak sharpness Q d This is a predetermined frequency f of the magnitude of the acoustic signal AC1 (first acoustic signal) emitted from the acoustic signal 121a (first acoustic signal) and / or the acoustic signal AC2 (second acoustic signal) emitted from the acoustic signal 123a (second acoustic signal) of the housing 12, assuming that the acoustic signal 121a is located in the center. th Peak sharpness Q c It is less responsive than that. In other words, the magnitude of the acoustic signal AC1 and / or acoustic signal AC2 emitted from the housing 12, where the position of the sound hole 121a is biased to a certain eccentric position, is a predetermined frequency f th The peaks described above correspond to a predetermined frequency f of the magnitude of the acoustic signal AC1 and / or acoustic signal AC2 emitted from the housing 12, assuming that the sound hole 121a is located in the central position. th The peak is flatter than the peak shown above. The position of the tone hole 121a may be shifted to such an eccentric position.

[0035] If the positions of one or more tone holes 121a are biased to eccentric positions, the distribution and opening area of ​​the tone holes 123a may be biased accordingly. For example, as shown in Figure 13A or Figure 13B, the positions of one or more tone holes 121a provided in region AR1 are biased to eccentric positions on axis A12, which is offset from axis A1, and as illustrated in Figures 14A and 14B, the opening area of ​​the tone holes 123a provided in region AR3 may also be biased toward the eccentric position on axis A12. In the example of Figure 14A, the number of tone holes 123a provided along unit arc region C1-3, which is far from the eccentric position on axis A12, is less than the number of tone holes 123a provided along unit arc region C1-1, which is closer to the eccentric position. In the example shown in Figure 14B, the opening area of ​​each tone hole 123a located along unit arc region C1-3, which is farther from the eccentric position on axis A12, is smaller than the opening area of ​​each tone hole 123a located along unit arc region C1-1, which is closer to the eccentric position. That is, when the circumference C1 is divided into multiple unit arc regions, the sum of the opening areas of the tone holes 123a (second tone holes) located along the first arc region (e.g., C1-3), which is one of the unit arc regions, is smaller than the sum of the opening areas of the tone holes 123a located along the second arc region (e.g., C1-1), which is one of the unit arc regions closer to the eccentric position than the first arc region. If the position of the tone hole 121a is eccentric, the distribution of the acoustic signal AC1 emitted from the tone hole 121a to the outside is also eccentric. Here, by shifting the distribution and opening area of ​​the sound holes 123a to an eccentric position, the distribution of the acoustic signal AC2 emitted to the outside from the sound holes 123a can also be shifted to an eccentric position. As a result, the sound leakage component of the acoustic signal AC1 can be sufficiently canceled out by the emitted acoustic signal AC2.

[0036] For other purposes, the sound hole 121a may be offset to an eccentric position, away from the center (central position) of region AR1 of the wall portion 121 of the housing 12, in order to control the resonant frequency of the housing 12. Furthermore, the size of the openings of the sound holes 121a and 123a, the thickness of the wall portion of the housing 12, and the internal volume of the housing 12 all affect the resonant frequency of the housing 12. Therefore, by controlling at least some of these, the resonant frequency of the housing 12 can be raised or lowered. That is, the larger the size of the openings of the sound holes 121a and 123a, the thinner the wall portion of the housing 12, and the smaller the internal volume of the housing 12, the higher the resonant frequency of the housing 12 can be. Conversely, the smaller the size of the openings of the sound holes 121a and 123a, the thicker the wall portion of the housing 12, and the larger the internal volume of the housing 12, the lower the resonant frequency of the housing 12 can be.

[0037] [Modification 3 of the First Embodiment] As described above, in the first embodiment and its modifications 1 and 2, an acoustic signal AC2, which is the inverse phase signal of the acoustic signal AC1 or an approximate signal of the inverse phase signal, is emitted from the sound hole 123a, and a portion of the emitted acoustic signal AC2 cancels out a portion of the acoustic signal AC1 emitted from the sound hole 121a (sound leakage component). For this purpose, when the direct wave of the acoustic signal AC1 is mainly emitted from the sound hole 121a, it is desirable that the direct wave of the acoustic signal AC2 is mainly emitted from the sound hole 123a. This is because, since reflected waves have a different propagation path from direct waves, if the acoustic signal AC2 emitted from the sound hole 123a contains reflected waves, the acoustic signal AC2 emitted from the sound hole 123a may exhibit a different phase from the inverse phase signal or approximate signal of the acoustic signal AC1 emitted from the sound hole 121a, which may reduce the efficiency of canceling out the sound leakage component. In other words, it is desirable that the enclosure 12 has an internal structure that suppresses the reflection of the acoustic signal AC2 (second acoustic signal) within the enclosure 12, and that the direct waves of the acoustic signal AC2 are mainly emitted from the sound hole 123a (second sound hole). The following is an example of such a configuration.

[0038] <Example 3-1> A reverberation-suppressing material (e.g., sponge or paper) may be installed in the internal areas of the walls of the enclosure 12 (e.g., areas AR2, AR3) to suppress reverberation. The walls of the enclosure 12 themselves may be made of the reverberation-suppressing material, or a sheet-like reverberation-suppressing material may be fixed to the walls of the enclosure 12. Alternatively, the shape of the internal areas of the walls of the enclosure 12 (e.g., areas AR2, AR3) may be made uneven to suppress reverberation. Alternatively, a sheet with an uneven surface shape that has a reverberation-suppressing effect may be fixed to the internal areas of the walls of the enclosure 12.

[0039] <Example 3-2> As illustrated in Figures 15A and 15B, the opening end of the sound hole 123a (second sound hole) may be directed toward the edge portion 112a of the other side 112 (D2 direction side) of the driver unit 11, and the sound hole 123a may be configured to emit a direct wave of the acoustic signal AC2 (second acoustic signal) mainly emitted from the other side 112 of the driver unit 11.

[0040] <Example 3-3> As illustrated in Figure 15B, the wall portion 122 (region AR2) located on the other side of the driver unit 11 may be in non-contact with the driver unit 11 (non-contact while the driver unit 11 is being driven), and the distance dis1 between the driver unit 11 and the wall portion 122 located on the other side 112 of the driver unit 11 may be 5 mm or less, and the direct wave of the acoustic signal AC2 (second acoustic signal) may be mainly emitted from the sound hole 123a (second sound hole). Note that region AR2 being in non-contact with the driver unit 11 while the driver unit 11 is being driven means, for example, that the distance dis1 is greater than the amplitude of the other side 112 of the driver unit 11 while it is being driven.

[0041] [Modification 4 of the First Embodiment] As mentioned above, the higher the frequencies of the acoustic signals AC1 and AC2, the shorter their wavelengths become, making it difficult to cancel out the sound leakage component of acoustic signal AC1 with acoustic signal AC2. In some cases, it may become difficult to phase-align the acoustic signals AC1 and AC2 at high frequencies, and conversely, the sound leakage component of acoustic signal AC1 may be amplified by acoustic signal AC2. Therefore, it may be better to suppress the emission of high-frequency acoustic signals AC2 from the sound holes 123a. For this reason, sound-absorbing material that absorbs high-frequency acoustic signals may be provided in the housing 12. This sound-absorbing material has the characteristic that its sound absorption coefficient for an acoustic signal of frequency f1 is greater than its sound absorption coefficient for an acoustic signal of frequency f2. However, frequency f1 is higher than frequency f2 (f1>f2). In other words, this sound-absorbing material suppresses the high-frequency components of the acoustic signal more than the low-frequency components. Frequency f1 is a predetermined frequency f2 th The following applies, and frequency f2 is the predetermined frequency f2 th Larger than the specified frequency f2. th Examples include 3000Hz, 4000Hz, 5000Hz, 6000Hz, etc. The sound absorption coefficient α of a sound-absorbing material is calculated by the energy of the acoustic signal input to the sound-absorbing material. in The energy of the acoustic signal reflected by the sound-absorbing material or the energy of the acoustic signal that passed through the sound-absorbing material is E out In that case, α = (E in -E out ) / E in It can be expressed as follows. Examples of such sound-absorbing materials include paper such as washi and hanshi, nonwoven fabrics, silk, and cotton.

[0042] <Example 4-1> The sound-absorbing material 13 may be provided in at least one of the sound holes 123a (second sound hole). For example, as illustrated in Figure 16A, the sound-absorbing material 13 may be packed into at least one of the sound holes 123a. At least one of the inside or outside of at least one of the sound holes 123a may be covered with the sound-absorbing material 13.

[0043] <Example 4-2> The sound-absorbing material 13 may be provided in the area on the other side 112 (D2 direction side) of the driver unit 11 inside the housing 12. For example, as illustrated in Figure 16B, the sound-absorbing material 13 may be fixed to the area AR2 of the wall portion 122 located on the other side 112 (D2 direction side) of the driver unit 11. The sound-absorbing material 13 may also be fixed to the inside of the wall portion 123.

[0044] <Example 4-3> The sound-absorbing material 13 may be provided in at least one of the sound holes 123a (second sound hole), and the sound-absorbing material 13 may also be provided in the area on the other side 112 (D2 direction side) of the driver unit 11 inside the housing 12. For example, as illustrated in Figure 16C, the sound-absorbing material 13 may be packed into at least one of the sound holes 123a, and the sound-absorbing material 13 may also be fixed to the area AR2 of the wall portion 122.

[0045] <Experimental Results> This section presents experimental results demonstrating the sound leakage suppression effect of the acoustic signal output device 10 of this modified example. In this experiment, experiments were conducted using the acoustic signal output device 10 of the first embodiment (no acoustic absorbent) and using the acoustic signal output device 10 with the sound hole 123a covered with an acoustic absorbent, as illustrated in this modified example (with acoustic absorbent). Washi paper was used as the acoustic absorbent. In this experiment, as shown in Figure 5B, the acoustic signal output device 10 was attached to both ears of a dummy head 1100 that mimicked a human head, and the acoustic signal was observed at positions P1 and P2. Position P1 is near the left ear 1120 of the dummy head 1100 (near the acoustic signal output device 10), and position P2 is 15 cm away from position P1.

[0046] Figure 17 illustrates the frequency characteristics of the acoustic signal observed at position P1 in Figure 5B, Figure 18 illustrates the frequency characteristics of the acoustic signal observed at position P2 in Figure 5B, and Figure 19 illustrates the difference between the frequency characteristics of the acoustic signal observed at position P1 and the frequency characteristics of the acoustic signal observed at position P2. The horizontal axis represents frequency (Frequency [Hz]), and the vertical axis represents sound pressure level (SPL) (dB)). The solid line graph illustrates the frequency characteristics when using the acoustic signal output device 10 with the sound holes 123a covered with sound-absorbing material (With acoustic absorbent), and the dashed line graph illustrates the frequency characteristics when using the acoustic signal output device 10 of the first embodiment (No acoustic absorbent). As illustrated in Figure 19, in the frequency band above 2000 Hz, the difference between the sound pressure of the acoustic signal observed at position P1 and the sound pressure of the acoustic signal observed at position P2 is generally larger when using an acoustic signal output device 10 with sound holes 123a covered with sound-absorbing material compared to when using an acoustic signal output device 10 without sound-absorbing material. This indicates that, in the frequency band above 2000 Hz, sound leakage at position P2 is generally suppressed more effectively when using an acoustic signal output device 10 with sound holes 123a covered with sound-absorbing material.

[0047] [Second Embodiment] Next, a second embodiment of the present invention will be described. The second embodiment is a modification of the first embodiment. In the following, the differences from the matters described so far will be the main focus of the description, and the explanation of matters already described will be simplified by using the same reference numerals.

[0048] In order to improve the sound quality of the acoustic signal output device 10 in the first embodiment or its modified form, it may be necessary to increase the size of the driver unit 11. However, in the first embodiment or its modified form, increasing the size of the driver unit 11 also increases the size and weight of the acoustic signal output device 10 itself. However, attaching a large and heavy acoustic signal output device 10 near the ear canal increases the burden on the ear and the feeling of a foreign object. Therefore, the housing with sound holes and the driver unit 11 may be made into separate components and connected by a waveguide. This makes it possible to increase the size of the driver unit 11 without increasing the size and weight of the housing attached near the ear canal. This will be explained in detail below.

[0049] The acoustic signal output device 20 of this embodiment is also an acoustic listening device that is worn without sealing the user's ear canal. As illustrated in Figure 20, the acoustic signal output device 20 of this embodiment includes a driver unit 11, a housing 22 having hollow sections AR21 and AR22 (first and second hollow sections), a housing 23 housing the driver unit 11 inside, hollow waveguides 24 and 25 (first and second waveguides) connecting the housing 22 and the housing 23, and hollow connecting members 26 and 27 connecting the waveguides 24 and 25 to the housing 22.

[0050] <Driver Unit 11> As illustrated in Figure 20, the driver unit 11 is a device that emits an acoustic signal AC1 (first acoustic signal) based on the input output signal to one side (D3 direction side) and an acoustic signal AC2 (second acoustic signal), which is the inverse phase signal of the acoustic signal AC1 or an approximate signal of the inverse phase signal, to the other side (D4 direction side). The configuration of the driver unit 11 is the same as in the first embodiment, except that the D1 direction is replaced by the D3 direction and the D2 direction is replaced by the D4 direction.

[0051] <Cabinet 23> As illustrated in Figure 20, the housing 23 is a hollow member with an outer wall and houses the driver unit 11 inside. There are no limitations on the shape of the housing 23, but it is desirable that the shape of the housing 23 be rotationally symmetric (line symmetric) or substantially rotationally symmetric about the axis A2 extending along the D3 direction. In this embodiment, for the sake of simplicity, an example is shown in which the housing 23 is substantially cylindrical with faces at both ends. However, this is just one example and does not limit the present invention. For example, the housing 23 may be substantially dome-shaped with walls at the ends, or it may be a hollow substantially cubic shape, or it may be any other three-dimensional shape. One end 241 of the waveguide 24 is attached to the wall 231 of the housing 23, which is located on the side of the face 111 on one side (the D3 direction side) of the driver unit 11. In this manner, the waveguide 24 (first waveguide), with one end 241 connected to one side (D3 direction side) of the driver unit 11, guides the acoustic signal AC1 emitted from the surface 111 of the driver unit 11 to the outside of the housing 23. One end 251 of the waveguide 25 is attached to the wall portion 232 of the housing 23, which is located on the other side (D4 direction side) of the driver unit 11 (surface 112). In this manner, the waveguide 25 (second waveguide), with one end 251 connected to the other side (D4 direction side) of the driver unit 11, guides the acoustic signal AC2 emitted from the surface 112 of the driver unit 11 to the outside of the housing 23. There are no limitations on the material that makes up the housing 23. The housing 23 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.

[0052] <Waveguide 24,25> As illustrated in Figure 20, waveguides 24 and 25 are, for example, hollow members configured in a tubular shape, and transmit acoustic signals AC1 and AC2 input from one end 241 and 251 to the other end 242 and 252, respectively, and emit from the other end 242 and 252. However, waveguides 24 and 25 are not limited to tubular shapes, and any structure that guides acoustic signals picked up at one end 241 and 251 (first position) to the other end 242 and 252 (second position), which is different from the one end 241 and 251 (first position), may be used. There are no limitations on the length of waveguides 24 and 25, but preferably, the length of the sound path of waveguide 24 and the length of the sound path of waveguide 25 are equal, or the difference between the length of the sound path of waveguide 24 and the length of the sound path of waveguide 25 is an integer multiple of the wavelength of the acoustic signals AC1 and AC2. In other words, if the length of the sound path in waveguide 24 (first waveguide) is L1, the length of the sound path in waveguide 25 (second waveguide) is L2, n is an integer, and acoustic signals AC1 (first acoustic signal) and AC2 (second acoustic signal) contain an acoustic signal with wavelength λ, then it is desirable that L1 = L2 + nλ be satisfied. Note that the sound path is the path through which sound travels, and in the case of waveguides 24 and 25 having the same inner diameter, a specific example of the length of the sound path in waveguides 24 and 25 is the length of waveguides 24 and 25. Note that there are no limitations on the material that constitutes waveguides 24 and 25. Waveguides 24 and 25 may be made of rigid materials such as synthetic resin or metal, or they may be made of elastic materials such as rubber.

[0053] <Joining member 26> The joining member 26 is a hollow member having an open end 261 located on one side, a wall portion 262 which is the bottom surface located on the other side of the open end 261, and a wall portion 263 which is the side surface that surrounds the space between the open end 261 and the wall portion 262 around the axis A1. In this embodiment, the axis A1 passes through the open end 261 and the wall portion 262. Preferably, the axis A1 is perpendicular or approximately perpendicular to the wall portion 262. Also preferably, the joining member 26 is rotationally symmetric with respect to the axis A1. In this embodiment, for the sake of simplicity, an example is shown in which the wall portion 263 is cylindrical, but the wall portion 263 may be other shapes such as a rectangular prism. The other end 242 of the waveguide 24 is attached to the wall portion 263, and the acoustic signal AC1 emitted from the other end 242 of the waveguide 24 is introduced into the interior of the joining member 26 (the space between the open end 261 and the wall portion 262). The acoustic signal AC1 introduced into the joint member 26 is emitted from the open end 261. There are no limitations on the material that constitutes the joint member 26. The joint member 26 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.

[0054] <Joining member 27> Similarly, the joining member 27 is a hollow member having an open end 271 located on one side, a wall portion 272 which is the bottom surface located on the other side of the open end 271, and a wall portion 273 which is the side surface that surrounds the space between the open end 271 and the wall portion 272 around the axis A1. In this embodiment, the axis A1 passes through the open end 271 and the wall portion 272. Preferably, the axis A1 is perpendicular or substantially perpendicular to the wall portion 272. Also preferably, the joining member 27 is rotationally symmetric with respect to the axis A1. In this embodiment, for the sake of simplicity, an example is shown in which the wall portion 273 is cylindrical, but the wall portion 273 may be other shapes such as a rectangular prism. The other end 252 of the waveguide 25 is attached to the wall portion 273, and the acoustic signal AC2 emitted from the other end 252 of the waveguide 25 is introduced into the interior of the joining member 27 (the space between the open end 271 and the wall portion 272). The acoustic signal AC2 introduced into the joint member 27 is emitted from the open end 271. There are no limitations on the material that constitutes the joint member 27. The joint member 27 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.

[0055] <Enclosure 22> As illustrated in Figures 20, 21A-21C, 22A, and 22B, the housing 22 of this embodiment has a wall portion 221 located on one side (D1 direction side), a wall portion 222 located on the other side (D2 direction side), a wall portion 223 surrounding the space between wall portions 221 and 222, and a wall portion 224 separating the space enclosed by wall portions 221, 222, and 223 into a hollow portion AR21 (first hollow portion) and a hollow portion AR22 (second hollow portion). In this embodiment, hollow portions AR21 and AR22 are arranged on the same axis A1 extending in the same D1 direction, for example, the central region of hollow portion AR21 and the central region of hollow portion AR22 are arranged on the same axis A1. It is desirable that the internal space of the hollow section AR21 be separated from the internal space of the hollow section AR22 by the wall section 224.

[0056] A connecting member 26 to which the other end 242 of the waveguide 24 is attached is fixed or integrated with the inner wall of the hollow section AR21, with the open end 261 of the connecting member 26 facing the wall 221. For example, the wall 262 side of the connecting member 26 is fixed or integrated with the wall 224 inside the hollow section AR21, and the open end 261 side faces the wall 221. In this embodiment, the center of the wall 262 and the open end 261 of the connecting member 26 is positioned on axis A1. As a result, the other end 242 of the waveguide 24 is connected to the hollow section AR21 via the connecting member 26, and the acoustic signal AC1 sent to the connecting member 26 is emitted from the open end 261 toward the wall 221 (direction D1). In other words, for example, the joining member 26 is positioned on the axis A1, and the open end 261 of the joining member 26 is open facing the direction D1 (first direction) along the axis A1, and the acoustic signal AC1 introduced from the other end 242 of the waveguide 24 is emitted in the direction D1 into the hollow section AR21.

[0057] A through-hole 222a is provided in the wall portion 222 of the hollow portion AR22. It is desirable that the through-hole 222a be located on the axis A1, and more preferably that the center of the through-hole 222a be located on the axis A1. There are no limitations on the shape of the through-hole 222a, but it is preferable that the opening portion of the through-hole 222a be rotationally symmetric with respect to the axis A1, and more preferably that the edge of the opening portion of the through-hole 222a be circular. A joining member 27 to which the other end 252 of the waveguide 25 is attached is fixed or integrated with the outside of the wall portion 222 of the housing 22, and the open end 271 side of the joining member 27 is oriented toward the through-hole 222a. In this embodiment, the wall portion 272, the open end 271, and the center of the through-hole 222a of the joining member 27 are located on the axis A1. As a result, the other end 252 of the waveguide 25 is connected to the hollow section AR22 via the joining member 27, and the acoustic signal AC2 sent to the joining member 27 is emitted from the open end 271 toward the internal space of the hollow section AR22. For example, the acoustic signal AC2 is emitted from the open end 271 toward the wall section 224 side (direction D1). That is, for example, the joining member 27 is positioned on axis A1, the open end 271 of the joining member 27 is open facing direction D1 (first direction) along axis A1, and the acoustic signal AC2 introduced from the other end 252 of the waveguide 25 is emitted toward direction D1 toward the interior of the hollow section AR22.

[0058] There are no limitations on the shape of the housing 22, but it is desirable that the shape of the housing 22 be rotationally symmetric or substantially rotationally symmetric about axis A1. In this embodiment, for the sake of simplicity, an example is shown in which the external shape of the housing 22 is substantially cylindrical with wall portions 221 and 222 at both ends and wall portion 223 at the side. In this embodiment, an example is also shown in which wall portions 221, 222, and 224 are perpendicular or substantially perpendicular to axis A1, and wall portion 223 is parallel or substantially parallel to axis A1. However, these are just examples and do not limit the present invention. For example, the external shape of the housing 22 may be substantially dome-shaped with wall portions at the ends, or hollow substantially cubic, or any other three-dimensional shape. Furthermore, there are no limitations on the material that constitutes the housing 22. The housing 22 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.

[0059] <Sound holes 221a, 223a> The wall portion 221 of the hollow portion AR21 (first hollow portion) is provided with a sound hole 221a (first sound hole) for guiding out the acoustic signal AC1 (first acoustic signal) introduced into the hollow portion AR21 by the waveguide 24 (first waveguide) to the outside. The wall portion 223 of the hollow portion AR22 (second hollow portion) is provided with a sound hole 223a (second sound hole) for guiding out the acoustic signal AC2 (second acoustic signal) introduced into the hollow portion AR22 by the waveguide 25 (second waveguide) to the outside. Similar to the sound holes 121a and 123a in the first embodiment, the sound holes 221a and 223a are, for example, through holes penetrating the wall portion of the housing 12, but this does not limit the present invention. The sound holes 221a and 223a do not have to be through holes as long as the acoustic signals AC1 and AC2 can be guided out to the outside, respectively.

[0060] The acoustic signal AC1 emitted from sound port 221a reaches the user's ear canal and is heard by the user. Meanwhile, an acoustic signal AC2, which is either the out-of-phase signal of acoustic signal AC1 or an approximate signal of the out-of-phase signal AC1, is emitted from sound port 223a. A portion of this acoustic signal AC2 cancels out a portion of the acoustic signal AC1 emitted from sound port 221a (sound leakage component). This suppresses sound leakage.

[0061] An example of the arrangement of tone holes 221a and 223a is shown. In this embodiment, the sound hole 221a (first sound hole) is provided in the wall portion 221 of the hollow portion AR21 located on one side of the joining member 26 (the D1 direction side, which is the side from which the acoustic signal AC1 is emitted) (Figures 20, 21A, 21B, and 22A). In addition, the sound hole 223a (second sound hole) in this embodiment is provided in the wall portion 223 that is in contact with the hollow portion AR22. That is, if we take the center of the hollow portion AR22 as the reference point, and define the direction between the D1 direction (first direction) and the opposite direction of the D1 direction as the D12 direction (second direction) (Figure 22A), then the sound hole 221a (first sound hole) is provided on the D1 direction side (first direction side) of the housing 22, and the sound hole 223a (second sound hole) is provided on the D12 direction side (second direction side) of the housing 22. In other words, the sound hole 221a opens facing the D1 direction (first direction) along the axis A1, and the sound hole 223a opens facing the D12 direction (second direction). For example, if the outer shape of the housing 22 has a first end face which is a wall portion 221 located on one side (D1 direction side) of the joining member 26, a second end face which is a wall portion 222 located on the other side (D2 direction side) of the joining member 26, and a side surface which is a wall portion 223 that surrounds the space sandwiched between the first end face and the second end face, centering on the axis A1 along the emission direction (D1 direction) of the acoustic signal AC1 passing through the first end face and the second end face (Figures 21B, 22A), then the sound hole 221a (first sound hole) is provided on the first end face, and the sound hole 223a (second sound hole) is provided on the side surface. In this embodiment, no sound holes are provided on the wall portion 222 side of the housing 22. If sound holes are provided on the wall portion 222 side of the housing 22, the sound pressure level of the acoustic signal AC2 emitted from the housing 22 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.

[0062] As illustrated in Figure 21A, the sound hole 221a in this embodiment is positioned on or near an axis A1 along the emission direction (D1 direction) of the acoustic signal AC1. The axis A1 in this embodiment passes through the center or near the center of the area of ​​the wall portion 221 located on one side (D1 direction side) of the joining member 26. For example, axis A1 is an axis that extends in the D1 direction through the central area of ​​the housing 22. That is, the sound hole 221a in this embodiment is provided at the central position of the area of ​​the wall portion 221 of the housing 22. 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 221a is circular (the open end is circular). However, this does not limit the present invention. For example, the shape of the edge of the open end of the sound hole 221a may be elliptical, square, triangular, or other shapes. Also, the open end of the sound hole 221a may be mesh-like. In other words, the open end of the sound hole 221a may be composed of multiple holes. Furthermore, in this embodiment, for the sake of simplicity, an example is shown in which one sound hole 221a is provided in the wall portion 221 of the housing 22. However, this does not limit the present invention. For example, two or more sound holes 221a may be provided in the wall portion 221 of the housing 22.

[0063] Similar to the first embodiment, as illustrated in Figures 21B and 22B, the sound holes 223a (second sound holes) in this embodiment are provided in multiple locations along a circumference C1 centered on an axis A1 along the emission direction of the acoustic signal AC1 (first acoustic signal). In this embodiment, for the sake of simplicity, an example is shown in which multiple sound holes 223a are provided on the circumference C1. However, it is sufficient that the multiple sound holes 223a are provided along the circumference C1, and it is not necessarily required that all sound holes 223a be strictly positioned on the circumference C1.

[0064] Furthermore, similar to the first embodiment, preferably, when the circumference C1 is divided equally into a plurality of unit arc regions, the sum of the opening areas of the tone holes 223a (second tone holes) provided along the first arc region, which is one of the unit arc regions, is the same as or approximately the same as the sum of the opening areas of the tone holes 223a (second tone holes) provided along the second arc region, which is one of the unit arc regions excluding the first arc region (Figure 22B).

[0065] Similar to the first embodiment, it is more desirable that the multiple sound holes 223a are provided along the circumference C1 with the same shape, size, and spacing. However, this does not limit the present invention.

[0066] In this embodiment, for the sake of simplicity, the case in which the edge of the open end of the tone hole 223a is rectangular is given as an example, but this does not limit the present invention. For example, the edge of the open end of the tone hole 223a may be circular, elliptical, triangular, or any other shape. Also, the open end of the tone hole 223a may be mesh-like. In other words, the open end of the tone hole 223a may be composed of multiple holes. Furthermore, there is no limit to the number of tone holes 223a; a single tone hole 223a may be provided in the wall portion 223 of the housing 22, or multiple tone holes 223a may be provided.

[0067] Similar to the first embodiment, it is desirable that the ratio S2 / S1 of the total opening area S2 of the sound holes 223a (second sound hole) to the total opening area S1 of the sound holes 221a (first sound hole) satisfies 2 / 3 ≤ S2 / S1 ≤ 4. Furthermore, when the outer shape of the housing 22 has a first end face which is a wall portion 221 located on one side (D1 direction side) of the joining member 26, a second end face which is a wall portion 222 located on the other side (D2 direction side) of the joining member 26, and a side surface which is a wall portion 223 that surrounds the space sandwiched between the first end face and the second end face, centered on an axis A1 along the emission direction (D1 direction) of the acoustic signal AC1 passing through the first end face and the second end face (Figures 21B, 22A), it is desirable that the ratio S2 / S3 of the total opening area S2 of the sound holes 223a to the total area S3 of the side surface satisfies 1 / 20 ≤ S2 / S3 ≤ 1 / 5.

[0068] <Usage Status> Figures 23A and 23B illustrate the usage of the acoustic signal output device 20. In the example shown in Figure 23A, one acoustic signal output device 20 is attached to the right ear 1010 and the left ear (not shown) of user 1000. Any attachment mechanism is used to attach the acoustic signal output device 20 to the ears. The housing 22 of the acoustic signal output device 20 is positioned on the ear canal 1011 side of the right ear 1010 and the left ear, with the D1 direction side of each facing the ear canal 1011 side of user 1000. The playback device 210, including the housing 23, is positioned behind the auricle of the right ear 1010 and the left ear, respectively, and as described above, the housing 23 and the housing 22 are connected by waveguides 24 and 25. The acoustic signal AC1 introduced from the driver unit 11 in the housing 23 to the hollow part AR21 of the housing 22 is emitted from the sound hole 221a, and the emitted acoustic signal AC1 is heard by user 1000. Meanwhile, the acoustic signal AC2 introduced from the driver unit 11 inside the housing 23 into the hollow portion AR22 of the housing 22 is emitted from the sound hole 223a. A portion of this acoustic signal AC2 is either the inverse phase signal of the acoustic signal AC1 or an approximate signal of the inverse phase signal, and cancels out a portion of the acoustic signal AC1 emitted from the sound hole 221a (sound leakage component).

[0069] As shown in the example in Figure 23B, the playback device 210, including the housing 23, is positioned on the head on the front side of the right ear 1010 and the left ear auricle, and the housing 23 and housing 22 may be connected by waveguides 24 and 25 as described above. Otherwise, it is the same as the example in Figure 23A.

[0070] [Modification 1 of the second embodiment] In the second embodiment, an example was shown in which multiple sound holes 223a (second sound holes) of the same shape, size, and spacing are provided along the circumference C1. However, this does not limit the present invention. For example, sound holes 223a with the same arrangement configuration as sound holes 123a in Modification 1 of the first embodiment may be provided in the housing 22 (Figures 10A to 12C).

[0071] [Modification 2 of the second embodiment] In the second embodiment, a configuration was illustrated in which one sound hole 221a is located at the center of the wall portion 221 of the housing 22. However, similar to the modification 2 of the first embodiment, multiple sound holes 221a may be provided in the area of ​​the wall portion 221 of the housing 22, or the sound holes 221a may be offset to an eccentric position away from the center of the area of ​​the wall portion 221 of the housing 22. For example, sound holes 221a with the same arrangement configuration as the sound hole 121a in the modification 2 of the first embodiment may be provided in the housing 22 (Figures 13A and 13B).

[0072] Furthermore, similar to Modification 2 of the First Embodiment, if the positions of one or more tone holes 221a are biased to eccentric positions, the distribution and opening area of ​​the tone holes 223a may be biased accordingly. That is, when the circumference C1 is divided equally into multiple unit arc regions, the sum of the opening areas of the tone holes 223a (second tone holes) provided along the first arc region, which is one of the unit arc regions, may be smaller than the sum of the opening areas of the tone holes 223a provided along the second arc region, which is one of the unit arc regions closer to an eccentric position than the first arc region. For example, tone holes 223a with the same arrangement configuration as tone holes 123a in Modification 2 of the First Embodiment may be provided in the housing 22 (Figures 14A and 14B). In addition, the resonant frequency of the housing 22 may be controlled by controlling the size of the openings of the tone holes 221a and 223a, the thickness of the walls of the housing 22, and at least a portion of the internal volume of the housing 22.

[0073] [Modification 3 of the second embodiment] The sound-absorbing material may be provided in the sound signal output device 20 such that its sound absorption coefficient for a frequency f1 sound signal is greater than its sound absorption coefficient for a frequency f2 (f1>f2) sound signal, as described in Modification 4 of the First Embodiment. The sound-absorbing material may be provided on the other side 112 (D4 direction side) of the driver unit 11 inside the housing 23, or inside the waveguide 25 (second waveguide), or at the end (open end portion) of the waveguide 25, or at least in one of the sound holes 223a (second sound hole), or inside the hollow portion AR22 (second hollow portion). For example, in Examples 4-1 to 4-3 of Modification 4 of the First Embodiment, the housing 12 may be replaced by a hollow portion AR22, the sound hole 123a may be replaced by a sound hole 223a, the region on the other side 112 of the driver unit 11 may be replaced by the internal region of the hollow portion AR22, and the region AR2 of the wall portion 122 may be replaced by the region of the wall portion 222.

[0074] [Modification 4 of the second embodiment] As in the second embodiment, by providing joining members 26 and 27, the emission direction of acoustic signals AC1 and AC2 within the hollow sections AR21 and AR22 can be controlled. For example, acoustic signal AC1 introduced from the other end 242 of waveguide 24 can be emitted in a direction D1 along axis A1 inside the hollow section AR21, and acoustic signal AC2 introduced from the other end 252 of waveguide 25 can be emitted in the same direction D1 inside the hollow section AR22. In this case, the sound pressure distribution of acoustic signal AC1 emitted from sound hole 221a and acoustic signal AC2 emitted from sound hole 223a can be made rotationally symmetric or substantially rotationally symmetric with respect to axis A1. This makes it possible to appropriately suppress sound leakage. However, this does not limit the present invention. For example, as illustrated in Figures 24, 25A, 25B, 25C, and 26, the acoustic signal output device 20 may not have a connecting member 26, and the other end 242 of the waveguide 24 may be directly connected to the wall 223 of the hollow section AR21, and the acoustic signal AC1 sent to the other end 242 of the waveguide 24 may be emitted towards the interior of the hollow section AR21. Similarly, the acoustic signal output device 20 may not have a connecting member 27, and the other end 252 of the waveguide 25 may be directly connected to the wall 223 of the hollow section AR22, and the acoustic signal AC2 sent to the other end 252 of the waveguide 25 may be emitted towards the interior of the hollow section AR22.

[0075] Furthermore, in the second embodiment, an example was shown in which the internal space of the hollow portion AR21 of the housing 22 is separated from the internal space of the hollow portion AR22 by the wall portion 224 (Figures 20, 21B, and 22A). However, the internal space of the hollow portion AR21 of the housing 22 does not have to be separated from the internal space of the hollow portion AR22. In such a case, it is preferable that the open end 261 of the joining member 26 faces the wall portion 221 side of the housing 22 (direction D1) (for example, the sound hole 221a side), and the open end 271 of the joining member 27 faces the wall portion 222 side of the housing 22 (direction D2). Even with such a configuration, the acoustic signal AC1 is emitted from the sound hole 221a and the acoustic signal AC2 is emitted from the sound hole 223a.

[0076] [Third Embodiment] Multiple acoustic signal output devices 10, as described in the first embodiment or its modifications, may be provided and controlled independently. This allows for independent control of the sound pressure level of the acoustic signal AC1 emitted from one acoustic signal output device 10 and the sound pressure level of the acoustic signal AC2 emitted from another acoustic signal output device 10. For example, one acoustic signal output device 10 and another acoustic signal output device 10 can be driven in opposite or nearly opposite phases, and their respective levels (power) at each frequency can be controlled independently. This allows for the cancellation of sound leakage components of the acoustic signal AC1 from each acoustic signal output device 10 by a portion of the acoustic signal AC2, as well as the cancellation of portions of the acoustic signals AC1 and AC2 output from different acoustic signal output devices 10. As a result, it becomes possible to more effectively cancel out sound leakage components. In this embodiment, for the sake of simplicity, an example is shown in which two acoustic signal output devices 10 are provided for one ear and controlled independently. However, this does not limit the present invention, and three or more acoustic signal output devices 10 may be provided for a single ear, and they may be controlled independently. Note that the same reference numerals will be used to omit further explanation of matters already described, but sub-numbers will be used to distinguish between multiple identical components. For example, two acoustic signal output devices 10 will be referred to as acoustic signal output device 10-1 and acoustic signal output device 10-2, but the configurations of acoustic signal output devices 10-1 and 10-2 are identical to those of acoustic signal output device 10.

[0077] The acoustic signal output device 30 of this embodiment is an acoustic listening device that is worn without sealing the user's ear canal. As illustrated in Figures 27 and 28, the acoustic signal output device 30 of this embodiment includes acoustic signal output devices 10-1, 10-2, a circuit section 31, and a connecting section 32.

[0078] <Acoustic signal output device 10-1> The configuration of the acoustic signal output device 10-1 is the same as that of the acoustic signal output device 10 illustrated in the first embodiment and its modified examples. That is, the acoustic signal output device 10-1 has a driver unit 11-1 (first driver unit) and a housing 12-1 (first housing portion) that houses the driver unit 11-1 inside. Based on the input output signal I (an electrical signal representing an acoustic signal), the driver unit 11-1 emits an acoustic signal AC1-1 (first acoustic signal) to the D1-1 direction (one side) and an acoustic signal AC2-1 (second acoustic signal), which is the inverse phase signal of the acoustic signal AC1-1 (first acoustic signal) or an approximate signal of the inverse phase signal, to the D2-1 direction (the other side). The wall portion 121-1 of the housing 12-1 is provided with one or more sound holes 121a-1 (first sound holes) for leading out the acoustic signal AC1-1 (first acoustic signal) emitted from the driver unit 11-1 to the outside. The wall portion 123-1 of the housing 12-1 is provided with one or more sound holes 123a-1 (second sound holes) for guiding the acoustic signal AC2-1 (second acoustic signal) emitted from the driver unit 11-1 to the outside. The details of the configuration of the acoustic signal output device 10-1 are the same as those of the acoustic signal output device 10 described in the first embodiment. For example, multiple sound holes 123a-1 (second sound holes) are provided along a circumference C1-1 (first circumference) centered on an axis A1-1 (first axis) that is parallel or substantially parallel to a straight line extending in direction D1-1 (first direction) (Figure 29). For example, if the circumference C1-1 (first circumference) is divided equally into multiple first unit arc regions, the sum of the opening areas of the tone holes 123a-1 (second tone holes) located along the first arc region, which is one of the first unit arc regions, is the same as or approximately the same as the sum of the opening areas of the tone holes 123a-1 (second tone holes) located along the second arc region, which is one of the first unit arc regions excluding the first arc region.

[0079] <Acoustic signal output device 10-2> The configuration of the acoustic signal output device 10-2 is the same as that of the acoustic signal output device 10 illustrated in the first embodiment and its modified examples. That is, the acoustic signal output device 10-2 has a driver unit 11-2 (second driver unit) and a housing 12-2 (second housing) that houses the driver unit 11-2 inside. Based on the input output signal II (an electrical signal representing an acoustic signal), the driver unit 11-2 emits an acoustic signal AC1-2 (fourth acoustic signal) to the D1-2 direction (one side) and an acoustic signal AC2-2 (third acoustic signal), which is the inverse phase signal of the acoustic signal AC1-2 or an approximate signal of the inverse phase signal, to the D2-2 direction (the other side). The phase of the acoustic signal AC1-2 (fourth acoustic signal) is the same as or approximates the phase of the acoustic signal AC2-1 (second acoustic signal). The phase of the acoustic signal AC2-2 (third acoustic signal) is the same as or approximates the phase of the acoustic signal AC1-1 (first acoustic signal). The driver unit 11-2 may be of the same design as the driver unit 11-1, or it may be of a different design. For example, the driver unit 11-2 may be smaller than the driver unit 11-1, or the performance of the driver unit 11-2 may be inferior to that of the driver unit 11-1. The wall portion 123-2 of the housing 12-2 is provided with one or more sound holes 123a-2 (third sound holes) for leading the acoustic signal AC2-2 (third acoustic signal) emitted from the driver unit 11-2 to the outside. The wall portion 121-2 of the housing 12-2 is provided with one or more sound holes 121a-2 (fourth sound holes) for leading the acoustic signal AC1-2 (fourth acoustic signal) emitted from the driver unit 11-2 to the outside. The details of the configuration of the acoustic signal output device 10-2 are the same as those of the acoustic signal output device 10 described in the first embodiment. For example, multiple sound holes 123a-2 (third sound holes) are provided along a circumference C1-2 (fourth circumference) centered on an axis A1-2 (fourth axis) that is parallel or substantially parallel to a straight line extending in direction D1-2 (fourth direction) (Figure 29).For example, if the circumference C1-2 (the fourth circumference) is divided equally into multiple fourth unit arc regions, the sum of the opening areas of the tone holes 123a-2 (third tone holes) located along the third arc region, which is one of the fourth unit arc regions, is the same as or approximately the same as the sum of the opening areas of the tone holes 123a-2 (third tone holes) located along the fourth arc region, which is one of the fourth unit arc regions excluding the third arc region.

[0080] <Connection part 32> As illustrated in Figures 27, 28, and 29, the connecting portion 32 fixes the housing 12-1 of the acoustic signal output device 10-1 and the housing 12-2 of the acoustic signal output device 10-2 to each other. In the example of Figure 28, the outside of the wall portion 123-1 of the housing 12-1 of the acoustic signal output device 10-1 is joined to the outside of the wall portion 123-2 of the housing 12-2 of the acoustic signal output device 10-2. The sound hole 121a-1 (first sound hole) opens facing the direction D1-1 (first direction) along the axis A1-1. Note that direction D1-1 is the direction along the axis A1-1. The sound hole 123a-1 (second sound hole) opens facing the direction D12-1 (second direction), which is between the direction D1-1 (first direction) and the opposite direction of direction D1-1 (first direction). The tone hole 121a-2 (fourth tone hole) opens facing the same or approximate direction D1-2 (fourth direction) as direction D1-1 (first direction). Direction D1-2 is along axis A1-2. The tone hole 123a-2 (third tone hole) opens facing D12-2 (third direction), which is between direction D1-2 (fourth direction) and the opposite direction of direction D1-2 (fourth direction). However, this arrangement is just one example and does not limit the present invention.

[0081] As illustrated in Figures 27, 28, and 29, preferably, the tone holes 121a-1 (first tone hole) and 121a-2 (fourth tone hole) are symmetrical or substantially symmetrical with respect to a reference plane P31 that includes a line parallel or substantially parallel to a line (axis A1-1) extending in direction D1-1 (first direction). Similarly, the tone holes 123a-1 (second tone hole) and 123a-2 (third tone hole) are preferably symmetrical or substantially symmetrical with respect to the reference plane P31. More preferably, the housing 12-1 (first housing portion) and housing 12-2 (second housing portion) are symmetrical or substantially symmetrical with respect to the reference plane P31.

[0082] <Circuit part 31> Circuit section 31 is a circuit that takes an input signal, which is an electrical signal representing an acoustic signal, as input and outputs output signal I, which is an electrical signal for driving driver unit 11-1, and output signal II, which is an electrical signal for driving driver unit 11-2. Output signals I and II are electrical signals representing acoustic signals, and output signal II is the inverse phase signal of output signal I or an approximate signal of said inverse phase signal. The configuration of circuit section 31 is illustrated below.

[0083] <Example of circuit section 31 configuration 1> The circuit unit 31 illustrated in Figure 30A includes a phase inversion unit 311, which is a phase inversion circuit. The input signal input to the circuit unit 31 is output as output signal I and supplied to the driver unit 11-1. Furthermore, the input signal input to the circuit unit 31 is also input to the phase inversion unit 311. The phase inversion unit 311 outputs a signal with the opposite phase of the input signal or an approximate signal of the opposite phase as output signal II. Output signal II is supplied to the driver unit 11-2.

[0084] <Example of circuit section 31 configuration 2> The circuit unit 31 illustrated in Figure 30B includes a level correction unit 312, a phase control unit 313, and a delay correction unit 314. The input signal input to the circuit unit 31 is input to the level correction unit 312 and the delay correction unit 314. The level correction unit 312 adjusts the level of each frequency band of the input signal and outputs the resulting band-level adjusted signal. In other words, if the designs (diameter, structure, etc.) of the driver units 11-1 and 2 are different from each other, the frequency characteristics of the acoustic signals output from the driver units 11-1 and 2 will also be different. The difference in the frequency characteristics of the acoustic signals output from the driver units 11-1 and 2 is related to the sound leakage cancellation effect. For example, if the housings 12-1 and 12-2 are symmetrical with respect to the reference plane P31, it is desirable that the frequency characteristics of the acoustic signals output from the driver units 11-1 and 2 be the same in order to enhance the sound leakage cancellation effect. Therefore, it is desirable to adjust the output signals so that the frequency characteristics of the acoustic signals output from the driver units 11-1 and 2 are the same. On the other hand, if housings 12-1 and 12-2 are not symmetrical with respect to the reference plane P31, it is desirable to adjust the balance of the frequency characteristics of the acoustic signals output from driver units 11-1 and 11-2 in accordance with their asymmetry so as to enhance the sound leakage cancellation effect. The level correction unit 312 achieves this by adjusting the level of each band of the input signal. The band-level adjusted signal output from the level correction unit 312 is input to the phase control unit 313. The phase control unit 313 generates an inverse phase signal of the band-level adjusted signal or an approximate signal of the inverse phase signal and outputs this as output signal II. The phase control unit 313 is, for example, a phase inversion circuit or an all-pass filter. If the phase control unit 313 is an all-pass filter, it can generate an inverse phase signal of the band-level adjusted signal or an approximate signal of the inverse phase signal by taking into account the phase characteristics of the level correction unit 312. Output signal II is supplied to driver unit 11-2. In addition, the delay correction unit 314 outputs an output signal I with the delay amount of the input signal adjusted. In other words, if a delay occurs in the processing (filtering) of the level correction unit 312 and the phase control unit 313, the delay correction unit 314 adjusts the amount of that delay.This allows for adjusting the phase of the acoustic signals output from the driver units 11-1 and 11-2, thereby improving the sound leakage suppression effect. Output signal I is supplied to driver unit 11-1. As described above, in the configuration example 2 of the circuit section 31, output signal I and output signal II based on the input signal can be controlled independently.

[0085] <Example of circuit section 31 configuration 3> As mentioned above, the higher the frequencies of acoustic signals AC1 and AC2, the shorter their wavelengths become, making it difficult to cancel out the sound leakage component of acoustic signal AC1 with acoustic signal AC2. For example, this cancellation becomes difficult in the frequency range above 6000Hz. Therefore, in such high frequency bands, acoustic signal AC2, which is intended to suppress sound leakage components, may actually exacerbate sound leakage. On the other hand, with earphones, the level of low-frequency sounds is weak, so the effect of sound leakage is small. For example, the effect of sound leakage is small in the frequency range below 2000Hz. Therefore, the importance of acoustic signal AC2 for suppressing sound leakage components is low in such low frequency bands. Furthermore, human auditory sensitivity to acoustic signals with frequencies between 2000Hz and 6000Hz is relatively high. In other words, the importance of acoustic signal AC2 for suppressing sound leakage components of acoustic signal AC1 in this frequency range is high.

[0086] From the above perspective, when allowing a user to hear the acoustic signal AC1 emitted from the sound hole 121a-1 of the acoustic signal output device 10-1, the frequency bandwidth of the acoustic signal emitted from the acoustic signal output device 10-2 may be limited more than the frequency bandwidth of the acoustic signal emitted from the acoustic signal output device 10-1. That is, the frequency bandwidth BW-2 of the acoustic signals AC2-2 and AC1-2 (third and fourth acoustic signals) emitted from the driver unit 11-2 (second driver unit) may be narrower than the frequency bandwidth BW-1 of the acoustic signals AC1-1 and AC2-1 (first and second acoustic signals) emitted from the driver unit 11-1 (first driver unit).

[0087] Example 31-1: For example, the high-frequency magnitude (level) of acoustic signals AC2-2 and AC1-2 may be suppressed more than the high-frequency magnitude of acoustic signals AC1-1 and AC2-1. That is, the frequency f of acoustic signals AC2-2 and AC1-2 (third and fourth acoustic signals) emitted from driver unit 11-2 (second driver unit) 31 The magnitude of components above (1st frequency) is the frequency f of the acoustic signals AC1-1 and AC2-1 (1st and 2nd acoustic signals) emitted from the driver unit 11-1 (1st driver unit). 31 The magnitude of the above components may be smaller. For example, the driver unit 11-2 has a frequency f 31 The above frequency band may be suppressed, and the resulting acoustic signals AC2-2 and AC1-2 may be output. Note that frequency f 31 Specific examples include 3000Hz, 4000Hz, 5000Hz, and 6000Hz.

[0088] Example 31-2: For example, the low-frequency magnitudes of acoustic signals AC2-2 and AC1-2 may be suppressed more than the low-frequency magnitudes of acoustic signals AC1-1 and AC2-1. That is, the frequency f of acoustic signals AC2-2 and AC1-2 (third and fourth acoustic signals) emitted from driver unit 11-2 (second driver unit) 32 The magnitude of components below (second frequency) is the frequency f of the acoustic signals AC1-1 and AC2-1 (first and second acoustic signals) emitted from the driver unit 11-1 (first driver unit). 32 The magnitude of the following components may be smaller. For example, the driver unit 11-2 has a frequency f 32 The following frequency bands may be suppressed in the output acoustic signals AC2-2 and AC1-2. 32 Specific examples include 1000Hz, 2000Hz, and 3000Hz.

[0089] Example 31-3: For example, the high-frequency magnitudes of acoustic signals AC2-2 and AC1-2 may be suppressed more than the high-frequency magnitudes of acoustic signals AC2-1 and AC1-1, and the low-frequency magnitudes of acoustic signals AC2-2 and AC1-2 may be suppressed more than the low-frequency magnitudes of acoustic signals AC2-1 and AC1-1. For example, the driver unit 11-2 has a frequency f 32 The following frequency bands and frequency f 31 The above frequency bands and the suppressed acoustic signals AC2-2 and AC1-2 (for example, frequency f 32 and frequency f 31 The system may output acoustic signals AC2-2 and AC1-2, which include only signals in the frequency band between the specified values.

[0090] The following is an example of the configuration 3 of the circuit section 31 that realizes these objectives. As illustrated in Figure 30C, the circuit section 31 in this example includes a level correction unit 312, a phase control unit 313, a delay correction unit 314, and a bandpass filter unit 315. The input signal input to the circuit section 31 is input to the bandpass filter unit 315 and the delay correction unit 314. The bandpass filter unit 315 obtains and outputs a band-limited signal that limits (narrows) the bandwidth of the input signal. In the case of the above example 31-1, the high-frequency side of the input signal (for example, frequency f 31 A signal with the above frequency bands suppressed is output as a band-limited signal. In the case of Example 31-2 above, the low-frequency side of the input signal (for example, frequency f) 32 A signal with the following frequency bands suppressed is output as a band-limited signal. In the case of Example 31-3 above, the high-frequency side of the input signal (for example, frequency f) 31 The above frequency bands) and the lower frequency side (for example, frequency f 32 A signal with the following frequency bands suppressed is output as a bandwidth-limited signal.

[0091] The bandwidth limiting signal is input to the level correction unit 312. The level correction unit 312 adjusts the level of each bandwidth of the bandwidth limiting signal and outputs the resulting bandwidth-level adjusted signal. The bandwidth-level adjusted signal output from the level correction unit 312 is input to the phase control unit 313. The phase control unit 313 generates an inverse phase signal of the bandwidth-level adjusted signal or an approximate signal of the inverse phase signal and outputs this as output signal II. Output signal II is supplied to the driver unit 11-2. In addition, the delay correction unit 314 outputs output signal I, which is an adjusted version of the input signal's delay amount.

[0092] <Usage Status> Figure 31 illustrates the usage state of the acoustic signal output device 30. In Figure 31, one acoustic signal output device 30 is attached to the right ear 1010 and the left ear (not shown) of user 1000. The D1 direction side of each acoustic signal output device 10-1 of the acoustic signal output device 30 is directed toward the external auditory canal 1011 of user 1000. The acoustic signal output device 10-2 is positioned offset from the external auditory canal 1011. For example, when the acoustic signal output device 30 is attached to the ear, the sound hole 121a-1 (first sound hole) is positioned toward the external auditory canal 1011, and the sound holes 123a-1 (second sound hole), 123a-2 (third sound hole), and 121a-2 (fourth sound hole) are positioned toward directions other than the external auditory canal 1011. Any attachment mechanism can be used to attach the acoustic signal output device 30 to the ear. The acoustic signal AC1-1 (first acoustic signal) emitted from the sound hole 121a-1 (first sound hole) of the acoustic signal output device 10-1 is heard by user 1000. On the other hand, a portion of the acoustic signal AC2-1 (second acoustic signal) emitted from the sound hole 123a-1 (second sound hole) cancels out a portion of the acoustic signal AC1-1 (first acoustic signal) emitted from the sound hole 121a-1 (first sound hole). Also, a portion of the acoustic signal AC2-2 (third acoustic signal) emitted from the sound hole 123a-2 (third sound hole) cancels out a portion of the acoustic signal AC1-2 (fourth acoustic signal) emitted from the sound hole 121a-2 (fourth sound hole). Furthermore, a portion of the acoustic signal AC2-2 (third acoustic signal) emitted from tone hole 123a-2 (third tone hole) cancels out a portion of the acoustic signal AC2-1 (second acoustic signal) emitted from tone hole 123a-1 (second tone hole). Also, a portion of the acoustic signal AC1-2 (fourth acoustic signal) emitted from tone hole 121a-2 (fourth tone hole) cancels out a portion of the acoustic signal AC1-1 (first acoustic signal) emitted from tone hole 121a-1 (first tone hole). In other words, in this embodiment, an acoustic signal AC1-1 (first acoustic signal) is emitted from the tone hole 121a-1 (first tone hole), an acoustic signal AC2-1 (second acoustic signal) is emitted from the tone hole 123a-1 (second tone hole), an acoustic signal AC2-2 (third acoustic signal) is emitted from the tone hole 123a-2 (third tone hole), and an acoustic signal AC1-2 (fourth acoustic signal) is emitted from the tone hole 121a-2 (fourth tone hole). In this case, the attenuation rate η of the acoustic signal AC1-1 (first acoustic signal) at position P2 (second point) with respect to position P1 (first point) is11 However, the attenuation rate η of the acoustic signal due to air propagation at position P2 (second point) relative to position P1 (first point) is 21 A predetermined value η that is smaller than th The following applies. Alternatively, in this case, the attenuation η of the acoustic signal AC1-1 (first acoustic signal) at position P2 (second point) relative to position P1 (first point) is 12 However, the attenuation of the acoustic signal due to air propagation at position P2 (second point) relative to position P1 (first point) is η 22 A predetermined value ω that is greater than th This concludes the explanation. In this embodiment, position P1 (first point) is a predetermined point to which the acoustic signal AC1-1 (first acoustic signal) emitted from the sound hole 121a-1 (first sound hole) reaches. On the other hand, position P2 (second point) in this embodiment is a predetermined point that is further from the acoustic signal output device 30 than position P1 (first point). As a result, sound leakage components from the acoustic signal output device 30 are canceled out. In particular, in this embodiment, the relative level of driver unit 11-2 to driver unit 11-1 can be controlled, so sound leakage can be reduced even further compared to the case where a single driver unit 11 is used as in the first embodiment.

[0093] Furthermore, as explained in Configuration Example 3 of Circuit Section 31, when allowing a user to hear the acoustic signal AC1 emitted from the sound hole 121a-1 of the acoustic signal output device 10-1, a sufficient sound leakage suppression effect can be expected by limiting the frequency band of the acoustic signal emitted from the acoustic signal output device 10-2 to be lower than the frequency band of the acoustic signal emitted from the acoustic signal output device 10-1. For example, as in Example 31-1, if the magnitude of the high-frequency side of acoustic signals AC2-2 and AC1-2 (for example, the high-frequency side where sound leakage suppression by cancellation is difficult) is suppressed more than the magnitude of the high-frequency side of acoustic signals AC2-1 and AC1-1, it is possible to suppress the exacerbation of sound leakage in the high-frequency range. Also, for example, as in Example 31-2, even if the magnitude of the low-frequency side of acoustic signals AC2-2 and AC1-2 is suppressed more than the magnitude of the low-frequency side of acoustic signals AC2-1 and AC1-1, the effect of sound leakage is small in applications where the level of low-frequency sounds is weak, such as with earphones. Furthermore, even if driver unit 11-2 is smaller or less powerful than driver unit 11-1, sufficient sound leakage suppression can still be expected.

[0094] [Modification 1 of the third embodiment] The acoustic signal output devices 10-1,2 may be the acoustic signal output device 10 described in the modified example of the first embodiment. For example, as illustrated in Figure 32A, the position of the sound hole 121a-1 (first sound hole) may be biased to a first eccentric position (a position on axis A12-1 which is parallel to axis A1-1 and offset from axis A1-1) which is offset from axis A1-1 (first central axis) which extends in direction D1-1 (first direction) through the central region of the housing 12-1 (first housing portion). Furthermore, as illustrated in Figure 32B, when the circumference C1-1 (first circumference) is divided equally into multiple first unit arc regions, the sum of the opening areas of the tone holes 123a-1 (second tone holes) provided along the first arc region, which is one of the first unit arc regions, may be smaller than the sum of the opening areas of the tone holes 123a-1 (second tone holes) provided along the second arc region, which is one of the first unit arc regions that is closer to the first eccentric position than the first arc region. Similarly, for example, the position of the tone hole 121a-2 (fourth tone hole) may be biased to a fourth eccentric position (a position on axis A12-2 which is parallel to axis A1-2 and shifted from axis A1-2) which is offset from axis A1-2 (second central axis) that extends in direction D1-2 (fourth direction) through the central region of the housing 12-2 (second housing portion). Furthermore, as illustrated in Figure 32B, when the circumference C1-2 (fourth circumference) is divided equally into multiple second unit arc regions, the sum of the opening areas of the tone holes 121a-2 (fourth tone holes) provided along the third arc region, which is one of the second unit arc regions, may be smaller than the sum of the opening areas of the fourth tone holes provided along the fourth arc region, which is one of the second unit arc regions that is closer to the fourth eccentric position than the third arc region. Even in such a case, it is preferable that the tone holes 121a-1 (first tone hole) and 121a-2 (fourth tone hole) are symmetrical or nearly symmetrical with respect to a reference plane P31 that includes a line parallel or nearly parallel to the line (axis A1-1) extending in direction D1-1 (first direction). Similarly, it is desirable that the tone holes 123a-1 (second tone hole) and 123a-2 (third tone hole) be symmetrical or substantially symmetrical with respect to the reference plane P31. More preferably, it is desirable that the housing 12-1 (first housing section) and housing 12-2 (second housing section) be symmetrical or substantially symmetrical with respect to the reference plane P31.Furthermore, the sound-absorbing material described in the modified version of the first embodiment may be provided in at least one of the acoustic signal output devices 10-1 and 10-2.

[0095] [Modification 2 of the third embodiment] In the third embodiment, the housing 12-1 (first housing portion) of the acoustic signal output device 10-1 and the housing 12-2 (second housing portion) of the acoustic signal output device 10-2 may be integrated. For example, as illustrated in Figure 33A, the housing 12-1 of the acoustic signal output device 10-1 and the housing 12-2 of the acoustic signal output device 10-2 may be replaced by a single housing 12", and the area AR31 in which the driver unit 11-1 is housed and the area AR32 in which the driver unit 11-2 is housed may be separated by a wall portion 351 provided inside the housing 12", with area AR31 being separated from area AR32. Furthermore, if regions AR31 and AR32 are separated by a wall 351, it is possible to suppress the cancellation of parts of acoustic signals AC1-1 and AC1-2, and parts of acoustic signals AC2-1 and AC2-2, within the housing 12" of the enclosure. For this reason, it is desirable that regions AR31 and AR32 be separated by a wall 351. However, regions AR31 and AR32 do not necessarily have to be separated by a wall 351. That is, parts of acoustic signals AC1-1 and AC2-1 emitted from driver unit 11-1 may not be emitted from any of the sound holes 121a-1, 123a-1, 121a-2, and 123a-2, and may be canceled out with parts of acoustic signals AC1-2 and AC2-2 emitted from driver unit 11-2 within the housing 12" of the enclosure. Even in this case, the components of the acoustic signals AC1-1, AC2-1, AC1-2, and AC2-2 that were not canceled out inside the housing 12" are emitted to the outside from one of the sound holes 121a-1, 123a-1, 121a-2, or 123a-2. For example, the components of the acoustic signals AC1-1 and AC2-1 emitted from the driver unit 11-1 that were not canceled out inside the housing 12" are emitted to the outside from one of the sound holes 121a-1, 123a-1, 121a-2, or 123a-2. It goes without saying that these are canceled out by some of the components of other acoustic signals emitted from either of the driver units 11-1 or 11-2 and emitted to the outside from one of the sound holes 121a-1, 123a-1, 121a-2, or 123a-2. Therefore, even in such a case, the sound leakage suppression effect can be obtained.Furthermore, even when housing 12-1 and housing 12-2 are integrated as housing 12”, it is desirable that the sound holes 121a-1 (first sound hole) and 121a-2 (fourth sound hole) be symmetrical or substantially symmetrical with respect to the reference plane P31. Similarly, it is desirable that the sound holes 123a-1 (second sound hole) and 123a-2 (third sound hole) be symmetrical or substantially symmetrical with respect to the reference plane P31. More preferably, it is desirable that housing 12-1 (first housing portion) and housing 12-2 (second housing portion) be symmetrical or substantially symmetrical with respect to the reference plane P31. In addition, the sound-absorbing material described in the modified example of the first embodiment may be provided inside housing 12”, or in any of the sound holes 121a-1, 121a-2, 123a-1, or 123a-2. Everything else is the same as in the third embodiment or its modified example 1.

[0096] [Modification 3 of the third embodiment] Instead of the acoustic signal output devices 10-1 and 2 of the third embodiment, acoustic signal output devices 20-1 and 2 having the same configuration as the acoustic signal output device 20 of the second embodiment may be used. For example, as illustrated in Figure 33B, the housings 22-1 and 22-2 of the acoustic signal output devices 20-1 and 20-2 are joined by a connecting part 32, and as described in the second embodiment, the housings 22-1 and 23-1 are connected by waveguides 24-1 and 25-1, and the housings 22-2 and 23-2 are connected by waveguides 24-2 and 25-2. The circuit unit 31 supplies output signal I to the driver unit 11-1 housed in housing 23-1 and outputs output signal II to the driver unit 11-2 housed in housing 23-2. As described in the second embodiment, the acoustic signal AC1-1 sent from housing 23-1 to housing 22-1 via waveguides 24-1 and 25-1 is emitted from sound hole 221a-1, and the acoustic signal AC2-1 is emitted from sound hole 223a-1. Similarly, the acoustic signal AC1-2 sent from housing 23-2 to housing 22-2 via waveguides 24-2 and 25-2 is emitted from sound hole 221a-2, and the acoustic signal AC2-2 is emitted from sound hole 223a-2. Other than the fact that housings 12-1, 12-2, sound holes 121a-1, 121a-2, 123a-1, 123a-2, and wall sections 121-1, 121-2, 122-1, 122-2, 123-1, 123-2 are replaced by housings 22-1, 22-2, sound holes 221a-1, 221a-2, 223a-1, 223a-2, and wall sections 221-1, 221-2, 222-1, 222-2, 223-1, 223-2, this is the same as the third embodiment or its modifications 1, 2. In addition, housing 23-1 may be connected to housing 22-1 by waveguides 24-1, 25-1 and to housing 23-1 by waveguides 24-2, 25-2. In this case, the circuit section 31 supplies an output signal I to the driver unit 11-1 housed in the housing 23-1. The acoustic signal AC1-1 sent from housing 23-1 to housing 22-1 via waveguides 24-1 and 25-1 is emitted from sound hole 221a-1, and the acoustic signal AC2-1 is emitted from sound hole 223a-1. Similarly, the acoustic signal AC1-2 sent from housing 23-1 to housing 22-2 via waveguides 24-2 and 25-2 is emitted from sound hole 221a-2, and the acoustic signal AC2-2 is emitted from sound hole 223a-2.Furthermore, housing 23-1 may be connected to κ housings 22-κ by waveguides 24-κ, 25-κ, where κ = 1, ..., κ. max And, κ max γ=κ is an integer greater than or equal to 2. In this case, the circuit unit 31 supplies output signal I to the driver unit 11-1 housed in the housing 23-1. The acoustic signal AC1-κ sent from housing 23-1 to housing 22-κ via waveguides 24-κ,25-κ is emitted from sound hole 221a-κ, and the acoustic signal AC2-κ is emitted from sound hole 223a-κ. In such a case, housing 23-2 and driver unit 11-2 may be omitted, and the circuit unit 31 may not output output signal II. Alternatively, housing 23-2 and driver unit 11-2 may not be omitted, and housing 23-2 may be further connected to another housing 22-γ via waveguides 24-γ,25-γ. However, γ=κ max +1,…,γ max And γ max is κ maxIt is an integer greater than . In this case, the output signal II output from the circuit section 31 is further supplied to the driver unit 11-2 housed in the housing 22-2, the acoustic signal AC1-γ sent from the housing 23-2 to the housing 22-γ via waveguides 24-γ, 25-γ is emitted from the sound hole 221a-γ, and the acoustic signal AC2-γ is emitted from the sound hole 223a-γ. That is, it is sufficient that the acoustic signal AC1-1 (first acoustic signal) emitted from one or more driver units is emitted to the outside from the sound hole 221a-1 (first sound hole). Also, it is sufficient that the acoustic signal AC2-1 (second acoustic signal) emitted from one or more of the said driver units is emitted to the outside from the sound hole 123a-1 (second sound hole). Furthermore, it is sufficient that the acoustic signal AC2-2 (third acoustic signal) emitted from one or more of the driver units is emitted from the sound hole 123a-2 (third sound hole). Also, it is sufficient that the acoustic signal AC1-2 (fourth acoustic signal) emitted from one or more of the driver units is emitted to the outside from the sound hole 221a-2 (fourth sound hole). In other words, the acoustic signal AC1-1 (first acoustic signal) and the acoustic signal AC2-2 (third acoustic signal) may be the same signal emitted from the same driver unit, or they may be different signals emitted from different driver units. Similarly, the acoustic signal AC2-1 (second acoustic signal) and the acoustic signal AC1-2 (fourth acoustic signal) may be the same signal emitted from the same driver unit, or they may be different signals emitted from different driver units.

[0097] [Fourth Embodiment] In the fourth embodiment, an example is shown in which an acoustic signal output device, worn on both ears without sealing the user's ear canal, emits monaural acoustic signals with inverted phases toward the left and right ears. Such an acoustic signal output device emits a portion of the monaural acoustic signal not only toward the user's ear canal but also toward the outside of the user. However, since monaural acoustic signals with inverted phases are emitted, the monaural acoustic signals that propagate toward the outside of the user cancel each other out, reducing sound leakage.

[0098] As illustrated in Figure 34A, the acoustic signal output device 4 of this embodiment includes an acoustic signal output unit 40-1 (first acoustic signal output unit) attached to the right ear (one ear) 1010 of the user 1000, an acoustic signal output unit 40-2 (second acoustic signal output unit) attached to the left ear (the other ear) 1020, and a circuit unit 41.

[0099] <Circuit section 41> Circuit section 41 is a circuit that takes an input signal, which is an electrical signal representing a monaural sound signal, as input and generates and outputs output signal I to be supplied to sound signal output section 40-1 and output signal II to be supplied to sound signal output section 40-2. Circuit section 41 in this embodiment has signal output sections 411 and 412 and a phase inversion section 413. The input signal is input to the phase inversion section 413 and the signal output section 412. The phase inversion section 413 outputs output signal I (first output signal), which is the inverse phase signal of the input signal or an approximate signal of the inverse phase signal. Signal output section 411 (first signal output section) outputs output signal I (first output signal) to sound signal output section 40-1 (first sound signal output section). Specifically, the signal output unit 411 (first signal output unit) outputs output signal I (first output signal) for outputting a monaural sound signal MAC1 (first monaural sound signal) from the acoustic signal output unit 40-1 (first acoustic signal output unit) attached to the right ear (one ear) 1010. The signal output unit 412 outputs the input signal as output signal II (second output signal) to the acoustic signal output unit 40-2 (second acoustic signal output unit). Specifically, the signal output unit 412 outputs output signal II (second output signal) for outputting a monaural sound signal MAC2 (second monaural sound signal) from the acoustic signal output unit 40-2 (second acoustic signal output unit) attached to the left ear (the other ear) 1020.

[0100] <Audio signal output section 40-1, 40-2> The acoustic signal output units 40-1 and 40-2 are devices for acoustic listening that are worn on both ears without sealing the user's external auditory canals. An output signal I is input to the acoustic signal output unit 40-1, and the acoustic signal output unit 40-1 converts the output signal I into a monaural acoustic signal MAC1 (a phase that is the same as or substantially the same as the phase of the monaural acoustic signal MAC1 is expressed as "+") and emits it toward the external auditory canal of the right ear 1010. An output signal II is input to the acoustic signal output unit 40-2, and the acoustic signal output unit 40-2 converts the output signal II into a monaural acoustic signal MAC2 (a phase that is the same as or substantially the same as the phase of the monaural acoustic signal MAC2 is expressed as "-") and emits it toward the external auditory canal of the left ear 1020. Here, the monaural acoustic signal MAC2 is an inverse phase signal of the monaural acoustic signal MAC1 or an approximate signal of the inverse phase signal of the monaural acoustic signal MAC1. However, even if the phases of the acoustic signals perceived by the left and right ears are inverted with respect to each other, almost no viewing problems occur. Also, although a part of the emitted monaural acoustic signal MAC1 and the monaural acoustic signal MAC2 is also emitted outside both ears, since the monaural acoustic signal MAC1 and the monaural acoustic signal MAC2 are in inverse phase or substantially inverse phase with respect to each other, they cancel each other out. That is, a part of the emitted monaural acoustic signal MAC1 (the first monaural acoustic signal) and a part of the emitted monaural acoustic signal MAC2 (a part of the second monaural acoustic signal) cancel each other out by interfering with each other outside the acoustic signal output unit 40-1 (the first acoustic signal output unit) worn on the right ear 1010 (one ear), and / or outside the acoustic signal output unit 40-2 (the second acoustic signal output unit) worn on the left ear 1020 (the other ear) (the outside of the user 1000, that is, the opposite side of the right ear 1010 side), and / or the outside of the acoustic signal output unit 40-2 (the second acoustic signal output unit) worn on the left ear 1020 (the other ear) (the outside of the user 1000, that is, the opposite side of the left ear 1020 side). That is, as described above, the monaural acoustic signal MAC1 (the first monaural acoustic signal) is output from the acoustic signal output unit 40-1 (the first acoustic signal output unit), and the monaural acoustic signal MAC2 (the second monaural acoustic signal) is output from the acoustic signal output unit 40-2 (the second acoustic signal output unit). In this case, the attenuation rate η of the monaural acoustic signal MAC1 (the first monaural acoustic signal) at the position P2 (the second point) based on the position P1 (the first point) 11 is the attenuation rate η due to air propagation of the acoustic signal at the position P2 (the second point) based on the position P1 (the first point)21 A predetermined value η that is smaller than th The following applies. Alternatively, in this case, the attenuation η of the first monaural sound signal at position P2 (second point) relative to position P1 (first point) 12 However, the attenuation of the acoustic signal due to air propagation at position P2 (second point) relative to position P1 (first point) is η 22 A predetermined value ω that is greater than th This concludes the explanation. However, in this embodiment, position P1 (first point) is a predetermined position to which the monaural sound signal MAC1 (first monaural sound signal) reaches. Also, in this embodiment, position P2 (second point) is further from the sound signal output unit 40-1 (first sound signal output unit) than position P1 (first point). As a result, sound leakage is suppressed.

[0101] [Modification 1 of the fourth embodiment] Instead of the acoustic signal output units 40-1 and 40-2, an acoustic signal output device 10 of the first embodiment or a modified version thereof may be used, or an acoustic signal output device 20 of the second embodiment or a modified version thereof may be used.

[0102] As illustrated in Figure 34B, this modified acoustic signal output device 4' has an acoustic signal output device 10-1 (first acoustic signal output unit) attached to the right ear (one ear) 1010 of user 1000, an acoustic signal output device 10-2 (second acoustic signal output unit) attached to the left ear (the other ear) 1020, and a circuit unit 41, or has an acoustic signal output device 20-1 (first acoustic signal output unit) attached to the right ear (one ear) 1010 of user 1000, an acoustic signal output device 20-2 (second acoustic signal output unit) attached to the left ear (the other ear) 1020, and a circuit unit 41.

[0103] The acoustic signal output device 10-1 or 20-1 (first acoustic signal output unit) includes a driver unit 11-1 (first driver unit) that emits a monaural acoustic signal MAC1-1 (first acoustic signal, first monaural acoustic signal) in the D1-1 direction (one side) and emits a monaural acoustic signal MAC2-1 (second acoustic signal), which is the inverse phase signal of the monaural acoustic signal MAC1-1 or an approximate signal of the inverse phase signal of the monaural acoustic signal MAC1-1, to the other side in the D1-1 direction. The device includes a housing 12-1 or 22-1 (first housing) in which one or more sound holes 121a-1 or 221a-1 (first sound holes) for leading out a monaural sound signal MAC1-1 (first sound signal) emitted from the driver unit 11-1 to the outside, and one or more sound holes 123a-1 or 223a-1 (second sound holes) for leading out a monaural sound signal MAC2-1 (second sound signal) emitted from the driver unit 11-1 to the outside are provided in the wall.

[0104] The acoustic signal output device 10-2 or 20-2 (second acoustic signal output unit) emits a monaural acoustic signal MAC1-2 (fourth acoustic signal, second monaural acoustic signal) which is the same as or similar to the monaural acoustic signal MAC2-1 (second acoustic signal) in the D1-2 direction (one side), and a driver unit 11-2 (second driver unit) emits a monaural acoustic signal MAC2-2 (third acoustic signal) which is the same as or similar to the monaural acoustic signal MAC1-1 (first acoustic signal) in the other side of the D1-2 direction. The system includes a nit unit, and a housing 12-2, 22-2 (second housing) in which one or more sound holes 123a-2 or 223a-2 (third sound holes) for leading out the monaural sound signal MAC2-2 (third sound signal) emitted from the driver unit 11-2 to the outside, and one or more sound holes 121a-2 or 221a-2 (fourth sound holes) for leading out the monaural sound signal MAC1-2 (fourth sound signal) emitted from the driver unit 11-2 are provided in the wall.

[0105] In this modified example, the acoustic signal AC1-1 (first acoustic signal) is the monaural acoustic signal MAC1-1 (first monaural acoustic signal), the acoustic signal AC2-1 is the monaural acoustic signal MAC2-1, the acoustic signal AC1-2 (fourth acoustic signal) is the monaural acoustic signal MAC1-2 (second monaural acoustic signal), and the acoustic signal AC2-2 is the monaural acoustic signal MAC2-2. The detailed configuration of the other acoustic signal output devices 10-1 and 10-2 is the same as that of the acoustic signal output device 10 in the first embodiment or its modified example. The detailed configuration of the acoustic signal output devices 20-1 and 20-2 is the same as that of the acoustic signal output device 20 in the second embodiment or its modified example.

[0106] When the acoustic signal output devices 4' are attached to both ears, the sound holes 121a-1 or 221a-1 of the acoustic signal output devices 10-1 or 20-1 are directed toward the right ear 1010 (i.e., the D1-1 direction is directed toward the right ear 1010), and the sound holes 121a-2 or 221a-2 of the acoustic signal output devices 10-2 or 20-2 are directed toward the left ear 1020 (i.e., the D1-2 direction is directed toward the left ear 1020).

[0107] From the sound holes 121a-1 or 221a-1 of the acoustic signal output device 10-1 or 20-1 (first acoustic signal output unit), a monaural acoustic signal MAC1-1 (first monaural acoustic signal) is emitted toward the ear canal of the right ear 1010. From the sound holes 121a-2 or 221a-2 of the acoustic signal output device 10-2 or 20-2 (second acoustic signal output unit), a monaural acoustic signal MAC1-2 (second monaural acoustic signal) is emitted toward the ear canal of the left ear 1020. Here, the monaural acoustic signal MAC1-2 is either the inverse phase signal of the monaural acoustic signal MAC1-1 or an approximate signal of the inverse phase signal of the monaural acoustic signal MAC1-1. However, even if the phases of the acoustic signals perceived by the left and right ears are inverted relative to each other, there are almost no listening problems. Furthermore, a portion of the emitted monaural acoustic signals MAC1-1 and MAC1-2 are also emitted outside both ears, but since MAC1-1 and MAC1-2 are out of phase or nearly out of phase with respect to each other, they cancel each other out. That is, a portion of the emitted monaural acoustic signal MAC1-1 (first monaural acoustic signal) and a portion of the emitted monaural acoustic signal MAC1-2 (second monaural acoustic signal) cancel each other out by interfering with each other on the outside of the acoustic signal output device 10-1 or 20-1 (first acoustic signal output unit) attached to the right ear 1010 (one ear) (outside the user 1000, i.e., opposite the right ear 1010 side), and / or on the outside of the acoustic signal output device 10-2 or 20-2 (second acoustic signal output unit) attached to the left ear 1020 (the other ear) (outside the user 1000, i.e., opposite the left ear 1020 side). Furthermore, a monaural acoustic signal MAC2-1 is emitted from the sound holes 123a-1 or 223a-1 of the acoustic signal output device 10-1 or 20-1 (first acoustic signal output unit). A portion of the emitted monaural acoustic signal MAC2-1 cancels out a portion of the monaural acoustic signal MAC1-1 emitted from the sound holes 121a-1 or 221a-1. In addition, a monaural acoustic signal MAC2-2 is emitted from the sound holes 123a-2 or 223a-2 of the acoustic signal output device 10-2 or 20-2 (second acoustic signal output unit). A portion of the emitted monaural acoustic signal MAC2-2 cancels out a portion of the monaural acoustic signal MAC1-2 emitted from the sound holes 121a-2 or 221a-2.As a result, sound leakage is suppressed.

[0108] [Modification 2 of the fourth embodiment] In the fourth embodiment or modified example 1 of the fourth embodiment, output signal I and output signal II may be reversed. That is, the input signal input to the circuit unit 41 is input to the phase inversion unit 413 and the signal output unit 412, the phase inversion unit 413 outputs output signal II (second output signal), which is the inverse phase signal of the input signal or an approximate signal of the inverse phase signal, to the acoustic signal output unit 40-2 (second acoustic signal output unit), and the signal output unit 412 outputs the input signal as is as output signal I (first output signal) to the acoustic signal output unit 40-1 (first acoustic signal output unit).

[0109] [Fifth Embodiment] In the fifth embodiment, an example of how to wear an ear-worn acoustic signal output device is provided. As mentioned above, conventional wearing methods can cause problems such as excessive strain on the ear or difficulty in achieving a stable fit. In this embodiment, a new wearing method for an acoustic signal output device is provided to solve these problems.

[0110] <Installation Method 1> Figures 35A to 36D illustrate mounting method 1. As illustrated in Figures 35A to 35C, the acoustic signal output device 2100 of mounting method 1 includes a housing 2112 that emits an acoustic signal, a mounting part 2121 (first mounting part) that holds the housing 2112 and is configured to be mounted on the upper part 1022 (first auricle portion) of the auricle 1020, which is part of the auricle 1020, and a mounting part 2122 (second mounting part) that holds the housing 2112 and is configured to be mounted on the intermediate part 1023 (second auricle portion), which is part of the auricle 1020 different from the upper part 1022 (first auricle portion). The intermediate part 1023 is the intermediate portion between the upper part 1022 (helix side) and the lower part 1024 (lobe side) of the auricle 1020. Furthermore, while this embodiment shows an example where the auricle 1020 is a human auricle, the auricle 1020 may also be the auricle of an animal other than a human (such as a chimpanzee).

[0111] The housing 2112 in this example may be any of the housings 12, 12, and 22 exemplified in the first to fourth embodiments and their variations, or it may be the housing of a conventional acoustic signal output device that emits an acoustic signal, such as earphones. When the acoustic signal output device 2100 is attached, the housing 2112 is positioned such that the sound hole 2112a faces the ear canal 1021 and the ear canal 1021 is not blocked.

[0112] In this example, the mounting portion 2121 (first mounting portion) has a fixing portion 2121a (first fixing portion) that grips the helix 1022a (end portion) of the upper part 1022 (first auricle portion) of the auricle 1020, and a support portion 2121b that fixes the fixing portion 2121a (first fixing portion) to the housing 2112. One end of the support portion 2121b holds a specific area of ​​the outer wall of the fixing portion 2121a, and the other end of the support portion 2121b holds a specific area H1 (first holding area) of the outer wall of the housing 2112. One end of the support portion 2121b may be fixed to the specific area of ​​the wall of the fixing portion 2121a, or it may be integrated with the wall of the fixing portion 2121a in that specific area. Similarly, the other end of the support portion 2121b may be fixed to a specific region H1 on the outer wall of the housing 2112, or it may be integrated with the outer wall of the housing 2112 in the specific region H1. In this way, the support portion 2121b holds the housing 2112 from the outer side (first outer side) of the specific region H1 on the wall of the housing 2112. In this example, when the fixing portion 2121a is attached to the helix 1022a, the outer side (first outer side) of region H1 becomes the upper portion 1022 side of the auricle 1020. Here, the fixing portion 2121a (first fixing portion) is configured to grip the helix 1022a of the upper portion 1022 (first auricle portion) of the auricle 1020 from above the auricle 1020. Furthermore, the housing 2112 is configured to be suspended by a mounting portion 2121 (first mounting portion), which includes a fixing portion 2121a (first fixing portion) that grips the helix 1022a. That is, the fixing portion 2121a grips the helix 1022a from the upper side of the auricle 1020, and the housing 2112 is suspended by the other end of a support portion 2121b that holds the fixing portion 2121a at one end. The reaction force against the weight of the housing 2112 suspended in this manner is supported by the inner wall surface of the fixing portion 2121a. For example, this reaction force is supported by the inner wall surface of the fixing portion 2121a, which is positioned perpendicular or approximately perpendicular to the direction of the reaction force. In this configuration, even if the gripping force of the fixing portion 2121a is small, it can support the weight of the housing 2112. The smaller the gripping force of the fixing portion 2121a, the less burden is placed on the auricle 1020, thus reducing the burden on the ear. The specific shape of the fixing part 2121a may be anything.An example of a fixing part 2121a is a member having a hollow shape with a C-shaped or U-shaped cross-section, configured to grip the earlobe 1022a while the earlobe 1022a is in contact with the inner wall surface 2121aa (for example, Figures 36A to 36D). For example, a fixing part 2121a with an ear cuff shape can be exemplified.

[0113] The mounting portion 2122 (second mounting portion) in this example has a fixing portion 2122a (second fixing portion) that grips the end of the intermediate portion 1023 (second auricle portion) of the auricle 1020, and a support portion 2122b that fixes the fixing portion 2122a (second fixing portion) to the housing 2112. One end of the support portion 2122b holds a specific region of the outer wall of the fixing portion 2122a, and the other end of the support portion 2122b holds a specific region H2 (second holding region) of the outer wall of the housing 2112. Region H2 is different from the region H1 described above. One end of the support portion 2122b may be fixed to the specific region of the wall of the fixing portion 2122a, or it may be integrated with the wall of the fixing portion 2122a in that specific region. Similarly, the other end of the support portion 2122b may be fixed to a specific region H2 on the outer wall of the housing 2112, or it may be integrated with the outer wall of the housing 2112 in the specific region H2. In this way, the support portion 2122b holds the housing 2112 from the outer side (a second outer side different from the first outer side) of the specific region H2 on the wall of the housing 2112. In this example, when the fixing portion 2122a is attached to the end of the intermediate portion 1023 of the auricle 1020, the outer side (second outer side) of region H2 becomes the intermediate portion 1023 side of the auricle 1020. As described above, the housing 2112 is held by the attachment part 2121 (first attachment part) on the upper part 1022 of the auricle 1020 from the outer side of region H1 (first outer side), and further held by the attachment part 2122 (second attachment part) on the middle part 1023 of the auricle 1020 from the outer side of region H2 (second outer side, different from the first outer side). This stabilizes the position of the housing 2112 attached to the auricle 1020. In addition, since the housing 2112 is held by the attachment part 2121 (first attachment part) and the attachment part 2122 (second attachment part) on different parts of the auricle 1020 (upper part 1022 and middle part 1023), the burden on the auricle 1020 caused by attachment can be distributed. Furthermore, the housing 2112 is attached to the auricle 1020 by attachment parts 2121 and 2122 that grip the end of the auricle 1020. These attachment parts 2121 and 2122 do not interfere with the temples of eyeglasses or the strings of a mask that are hooked onto the back of the auricle 1020. The specific shape of the fixing part 2122a can be anything.An example of a fixing part 2122a is a hollow member having a C-shaped or U-shaped cross-section, configured to grip the intermediate portion 1023 of the auricle 1020 while the helix 1022a is in contact with the inner wall surface 2122aa. For example, a fixing part 2122a with an ear cuff shape can be cited.

[0114] There are no limitations on the materials that make up the mounting portion 2121 and the mounting portion 2122. The mounting portion 2121 and the mounting portion 2122 may be made of a rigid material such as synthetic resin or metal, or they may be made of an elastic material such as rubber.

[0115] <Installation Method 2> Mounting method 2 is illustrated using Figures 37A to 37C. As illustrated in Figures 37A to 37C, the acoustic signal output device 2100' of mounting method 2 is further modified by adding a mounting part 2123 (second mounting part) to the acoustic signal output device 2100 of mounting method 1, which is configured to be mounted on the lower part 1024 (second auricle portion), which is a part of the auricle 1020 that is different from the upper part 1022 (first auricle portion) and the middle part 1023 (second auricle portion) of the auricle 1020.

[0116] The mounting portion 2123 (second mounting portion) in this example has a fixing portion 2123a (second fixing portion) that grips the end of the lower portion 1024 (second auricle portion) of the auricle 1020, and a support portion 2123b that fixes the fixing portion 2123a (second fixing portion) to the housing 2112. One end of the support portion 2123b holds a specific region of the outer wall of the fixing portion 2123a, and the other end of the support portion 2123b holds a specific region H3 (second holding region) of the outer wall of the housing 2112. Region H3 is different from regions H1 and H2 described above. One end of the support portion 2123b may be fixed to the specific region of the wall of the fixing portion 2123a, or it may be integrated with the wall of the fixing portion 2123a in that specific region. Similarly, the other end of the support portion 2123b may be fixed to a specific region H3 on the outer wall of the housing 2112, or it may be integrated with the outer wall of the housing 2112 in the specific region H3. In this way, the support portion 2123b holds the housing 2112 from the outer side (a second outer side different from the first outer side) of the specific region H3 on the wall of the housing 2112. In this example, when the fixing portion 2123a is attached to the end of the lower portion 1024 of the auricle 1020, the outer side (second outer side) of region H3 becomes the lower portion 1024 side of the auricle 1020. In this way, the housing 2112 is further held to the lower portion 1024 of the auricle 1020 from the outer side (a second outer side different from the first outer side) of region H3 by the attachment portion 2123 (second attachment portion). This further stabilizes the position of the housing 2112 attached to the auricle 1020. Furthermore, the housing 2112 is held on different parts of the auricle 1020 (upper part 1022, middle part 1023, and lower part 1024) by the mounting parts 2121 (first mounting part), 2122 (second mounting part), and 2123 (second mounting part), thus distributing the burden on the auricle 1020 caused by wearing it. In addition, the housing 2112 is attached to the auricle 1020 by the mounting parts 2121, 2122, and 2123 which grip the ends of the auricle 1020. Such mounting parts 2121, 2122, and 2123 do not interfere with the temples of eyeglasses or the strings of a mask that are hooked onto the back of the auricle 1020. The specific shape of the fixing part 2123a can be anything.An example of the fixing part 2123a is a member having a hollow shape with a C-shaped or U-shaped cross-section, configured to grip the lower portion 1024 of the auricle 1020 while the helix 1022a is in contact with the inner wall surface 2123aa. For example, a fixing part 2123a with an ear cuff shape can be exemplified. There are no limitations on the material that constitutes the attachment part 2123.

[0117] <Mounting Method 3> The mounting portion 2122 of the acoustic signal output device 2100' in mounting method 2 may be omitted.

[0118] <Mounting Method 4> As illustrated in Figure 38, the mounting portion 2121 of the acoustic signal output device 2100 of mounting method 1 may be replaced with a mounting portion 2224 of the type that hooks onto the back of the upper portion 1022 of the auricle 1020 (like the temple of eyeglasses). The mounting portion 2224 is a rod-shaped member. One end of the mounting portion 2224 is bent so as to hook onto the back of the upper portion 1022 of the auricle 1020, and the other end holds a specific area H1 (first holding area) on the outer wall of the housing 2112. The other end of the mounting portion 2224 may be fixed to the specific area H1 on the outer wall of the housing 2112, or it may be integrated with the outer wall of the housing 2112 in the specific area H1. Similarly, the mounting portion 2121 of the acoustic signal output device 2100' of mounting methods 2 and 3 may be replaced with a mounting portion 2224 that hooks onto the back of the upper portion 1022 of the auricle 1020. There are no limitations on the material that constitutes the mounting portion 2224.

[0119] <Mounting Method 5> As illustrated in Figure 39A, the mounting portion 2122 of the mounting method 1 acoustic signal output device 2100 may be replaced with a mounting portion 2124 (second mounting portion) that clamps the end of the intermediate portion 1023 (second auricle portion) of the auricle 1020. The mounting portion 2124 (second mounting portion) has a fixing portion 2124a (second fixing portion) that clamps the end of the intermediate portion 1023 (second auricle portion) of the auricle 1020, and a support portion 2124b that fixes the fixing portion 2124a (second fixing portion) to the housing 2112. One end of the support portion 2124b holds the end of the fixing portion 2124a, and the other end of the support portion 2124b holds a specific region H2 (second holding region) of the outer wall of the housing 2112. One end of the support portion 2124b may be fixed to the end of the fixing portion 2124a, or it may be integrated with the end of the fixing portion 2124a. Similarly, the other end of the support portion 2124b may be fixed to a specific region H2 of the outer wall of the housing 2112, or it may be integrated with the outer wall of the housing 2112 in the specific region H2. In this way, the support portion 2124b holds the housing 2112 from the outside side (a second outside side different from the first outside side) of the specific region H2 of the wall of the housing 2112. As described above, the housing 2112 is held by the attachment part 2121 (first attachment part) on the upper part 1022 of the auricle 1020 from the outer side of region H1 (first outer side), and further held by the attachment part 2124 (second attachment part) on the middle part 1023 of the auricle 1020 from the outer side of region H2 (second outer side, different from the first outer side). This stabilizes the position of the housing 2112 attached to the auricle 1020. In this case as well, since the housing 2112 is held by the attachment part 2121 (first attachment part) and the attachment part 2124 (second attachment part) on different parts of the auricle 1020 (upper part 1022 and middle part 1023), the burden on the auricle 1020 due to attachment can be distributed. Furthermore, the attachment parts 2121 and 2124 do not interfere with the temples of eyeglasses or the strings of a mask that are hooked onto the back of the auricle 1020. In addition, the clamping fixing part 2124a (second fixing part) may be configured to clamp the lower part 1024 of the auricle 1020 instead of the middle part 1023 of the auricle 1020. The specific shape of the fixing part 2124a may be any.For example, the fixing part 2124a may be a clip-shaped clamping mechanism or an integrated leaf spring. Furthermore, there are no limitations on the material that constitutes the mounting part 2124.

[0120] <Mounting method 6> As illustrated in Figure 39B, the mounting portion 2121 of the acoustic signal output device 2300 in mounting method 5 may be replaced with a mounting portion 2224 that hooks onto the back of the upper portion 1022 of the auricle 1020. The configuration of the mounting portion 2224 is the same as in mounting method 4.

[0121] <Mounting Method 7> When the housing 2112 is the housings 12, 12", 22 exemplified in the first to fourth embodiments and their modified examples, the opening area of the sound holes 123a, 223a (second sound holes) provided in a region (shielding region) shielded by the mounting portions 2121, 2122, 2123, 2124, 2224 or in the vicinity thereof from the sound holes 121a, 221a (first sound holes) of the housings 12, 12", 22 may be made smaller than the opening area of the sound holes 123a, 223a (second sound holes) provided at a position away from the shielding region. As described above, a part of the acoustic signal AC1 (first acoustic signal) emitted from the sound holes 121a, 221a (first sound holes) of the housings 12, 12", 22 is canceled by the acoustic signal AC2 (second acoustic signal) emitted from the sound holes 123a, 223a (second sound holes), thereby suppressing sound leakage. Here, in the shielding region, the sound pressure of the acoustic signal AC1 (first acoustic signal) leaking to the outside is smaller than that in other regions. In accordance with this, by reducing the opening area of the sound holes 123a, 223a (second sound holes) provided in the shielding region or in the vicinity thereof, it is possible to balance the distribution of the sound pressure of the acoustic signal AC1 (first acoustic signal) leaking to the outside and the distribution of the sound pressure of the acoustic signal AC2 (second acoustic signal) emitted from the sound holes 123a, 223a (second sound holes). That is, the acoustic signal AC1 (first acoustic signal) is emitted from the sound holes 121a, 221a (first sound holes), and the acoustic signal AC2 (second acoustic signal) is emitted from the sound holes 123a, 223a (second sound holes). In this case, the attenuation rate η 11 of the acoustic signal AC1 (first acoustic signal) at the position P2 (second point) based on the position P1 (first point) 21 is smaller than a predetermined value η th of the attenuation rate of the acoustic signal due to air propagation at the position P2 (second point) based on the position P1 (first point), and the balance of the sound pressure distribution can be achieved as follows. Or, in this case, the attenuation amount η 12 of the acoustic signal AC1 (first acoustic signal) at the position P2 (second point) based on the position P1 (first point) 22 is larger than a predetermined value ω thAs described above, the sound pressure distribution can be balanced. Here, position P1 (first point) is a predetermined point to which the acoustic signal AC1 (first acoustic signal) emitted from the sound hole 221a (first sound hole) reaches. Also, position P2 (second point) is a predetermined point that is further from the acoustic signal output device than position P1 (first point). As a result, sound leakage can be effectively suppressed.

[0122] The following describes an example in which housing 2112 is housing 12 of the first embodiment or a modified version thereof, and this housing 12 (housing 2112) is held by mounting parts 2121, 2122 of mounting method 1. However, this does not limit the present invention. Housing 2112 may be housings 12, 12”, 22 as exemplified in the second to fourth embodiments and their modified versions, or this housing 12, 12”, 22 may be held by mounting parts 2121, 2122, 2123, 2124, 2224 of mounting methods 2 to 6. In this case as well, the following configuration can be applied.

[0123] As illustrated in Figure 40A, the acoustic signal output device 2100 in this case has a driver unit 11 that emits an acoustic signal AC1 (first acoustic signal) to one side (direction D1) and an acoustic signal AC2 (second acoustic signal), which is the inverse phase signal of the acoustic signal AC1 (first acoustic signal) or an approximate signal of the inverse phase signal, to the other side (direction D2). As described above, the walls 121 and 123 of the housing 12 are provided with one or more sound holes 121a (first sound holes) for leading out the acoustic signal AC1 (first acoustic signal) emitted from the driver unit 11 to the outside, and one or more sound holes 123a (second sound holes) for leading out the acoustic signal AC2 (second acoustic signal) emitted from the driver unit 11 to the outside. As described above, sound leakage is suppressed by a portion of the acoustic signal AC2 (second acoustic signal) emitted from the sound hole 123a (second sound hole) canceling out a portion of the acoustic signal AC1 (first acoustic signal) emitted from the sound hole 121a (first sound hole). As described above, the support portion 2121b of the mounting portion 2121 (first mounting portion) holds region H1 (first holding region) of the wall portion 123 of the housing 12 (housing 2112), and the support portion 2122b of the mounting portion 2122 (second mounting portion) holds region H2 (second holding region) of the wall portion 123 of the housing 12 (housing 2112). Here, the sound hole 121a (first sound hole) is located on one side (D1 direction side) of the space partitioned by a virtual plane P51 passing through region H1 (first holding region) and the mounting portion 2122 (second mounting portion). On the other hand, the sound hole 123a (second sound hole) is located on the other side (direction D2) of the space partitioned by the virtual plane P51. Here, the opening area of ​​the sound hole 123a (second sound hole), which is provided in or near the shielding region AR51 where the acoustic signal AC1 (first acoustic signal) is blocked by the support portion 2121b of the mounting portion 2121 (first mounting portion) or the support portion 2122b of the mounting portion 2122 (second mounting portion), is reduced. That is, as illustrated in Figure 40B, the sound hole 123a (second sound hole) is provided along the aforementioned circumference C1. Furthermore, it is assumed that the surface of the wall portion 123 of the housing 12 is equally divided into multiple unit area regions (in this example, unit area regions C5-1, C5-2, C5-3, C5-4) along the circumference C1.In this example, the number of sound holes 123a (second sound holes) provided in the first unit area region (in this example, unit area regions C5-2, C5-3), which is one of the unit area regions including the shielding region AR51, is less than the number of sound holes 123a (second sound holes) provided in the second unit area region (in this example, unit area regions C5-1, C5-4), which is one of the unit area regions not including the shielding region AR51. In this case, the sum of the opening areas of the sound holes 123a (second sound holes) provided in the first unit area region (in this example, unit area regions C5-2, C5-3), which is one of the unit area regions including the shielding region AR51, is smaller than the sum of the opening areas of the sound holes 123a (second sound holes) provided in the second unit area region (in this example, unit area regions C5-1, C5-4), which is one of the unit area regions not including the shielding region AR51. This effectively suppresses sound leakage.

[0124] As illustrated in Figures 41A and 41B, the number of tone holes 123a (second tone holes) provided in the first unit area region including the shielding region AR51 (in this example, unit area regions C5-2, C5-3) is less than the number of tone holes 123a (second tone holes) provided in the second unit area region not including the shielding region AR51 (in this example, unit area regions C5-1, C5-4). Furthermore, tone holes 123a with a larger opening area than those in the first unit area region may be provided in the second unit area region. Alternatively, the number of tone holes 123a may be equal in the first and second unit area regions, and the opening area of ​​each tone hole 123a provided in the first unit area region may be smaller than the opening area of ​​each tone hole 123a provided in the second unit area region. Even in this case, the sum of the opening areas of the tone holes 123a (second tone holes) located in the first unit area region (in this example, unit area regions C5-2, C5-3) is smaller than the sum of the opening areas of the tone holes 123a (second tone holes) located in the second unit area region (in this example, unit area regions C5-1, C5-4). Sound leakage can be effectively suppressed in this way as well.

[0125] <Mounting method 8> Mounting method 8 is illustrated using Figures 42, 43A, and 43B. As illustrated in Figures 42 and 43A, the acoustic signal output device 2500 of mounting method 8 includes a housing 2112 that emits an acoustic signal, and a mounting part 2221 that holds the housing 2112 and is configured to be attached to the auricle 1020.

[0126] The mounting portion 2221 includes a fixing portion 2221a having a concave inner wall surface 2221aa configured to fit into the upper portion 1022 of the auricle 1020, and a shielding wall 2221b configured to cover only a portion of the auricle 1020 when the inner wall surface 2221aa side of the fixing portion 2221a is fitted into the upper portion 1022 of the auricle 1020. In this example, the fixing portion 2221a has a hollow structure that accommodates at least a portion of the upper portion 1022 of the auricle 1020 (e.g., the helix 1022a). Considering the load on the auricle 1020, it is desirable that the inner wall surface 2221aa of the fixing portion 2221a be curved. However, this does not limit the present invention. The shielding wall 2221b is a plate with a flat or curved wall surface. In this example, the shielding wall 2221b is configured such that when the inner wall surface 2221aa side of the fixing part 2221a is fitted onto the upper portion 1022 of the auricle 1020, it covers the upper portion 1022 of the auricle 1020 while leaving the lower portion 1024 of the auricle 1020 open to the outside. That is, the end 2221c (the end opposite to the fixing part 2221a) of the shielding wall 2221b is an open portion O51. The open portion O51 is positioned so that when the upper portion 1022 of the auricle 1020 is fitted onto the inner wall surface 2221aa side of the fixing part 2221a, the lower portion 1024 of the auricle 1020 is open to the outside. There are no limitations on the material that constitutes the mounting part 2221.

[0127] The housing 2112 in this example may be any of the housings 12, 12, and 22 exemplified in the first to fourth embodiments and their variations, or it may be the housing of a conventional acoustic signal output device that emits an acoustic signal, such as an earphone. The housing 2112 is held on the inner wall surface 2221bb side of the shielding wall 2221b, and the sound hole 2112a that emits an acoustic signal opens in the opposite direction from the inner wall surface 2221bb. When the acoustic signal output device 2500 is attached to the auricle 1020, the outer wall surface 2221ba side of the shielding wall 2221b faces outward, and the inner wall surface 2221bb side of the shielding wall 2221b faces inward (ear). The housing 2112, which is held by the inner wall surface 2221bb and faces the auricle 1020 side, has its sound hole 2112a facing the ear canal 1021 side, and is positioned so that the housing 2112 does not block the ear canal 1021. In this case, since the sound hole 2112a is positioned on the inside side of the shielding wall 2221b, the influence of external noise is suppressed, and sound leakage of the acoustic signal emitted from the sound hole 2112a is also suppressed. Furthermore, since the shielding wall 2221b covers only a part of the auricle 1020 (the lower part 1024 side of the auricle 1020 is not blocked), external sounds are not completely blocked, and the user can hear external sounds.

[0128] <Mounting Method 9> As illustrated in Figure 44, the acoustic signal output device 2500' of mounting method 9 is a modified version of the acoustic signal output device 2500 of mounting method 8, in which the mounting portion 2221 of the acoustic signal output device 2500 is replaced by the mounting portion 2221'. The mounting portion 2221' is in which the shielding wall 2221b of the mounting portion 2221 is replaced by the shielding wall 2221b'. The shielding wall 2221b' is configured such that when the inner wall surface 2221aa side of the fixing portion 2221a is fitted into the upper portion 1022 of the auricle 1020, a part of the upper portion 1022 of the auricle 1020 is further opened to the outside. In other words, the end 2221c (the end opposite to the fixing part 2221a) of the shielding wall 2221b' is an open part O51, and a part of the shielding wall 2221b' on the fixing part 2221a side is also an open part O52 (through hole). The open part O52 is provided in a position that opens a part of the upper part 1022 of the auricle 1020 to the outside. Otherwise, it is the same as the wearing method 8. Since the shielding wall 2221b' covers only a part of the auricle 1020 (the lower part 1024 side and the upper part 1022 side of the auricle 1020 are not blocked), external sounds are not completely blocked, and the user can hear external sounds.

[0129] <Mounting method 10> When the housing 2112 is one of the housings 12,12”,22 exemplified in the first to fourth embodiments and their variations, it is desirable that the sound holes 121a,221a (first sound holes) of the housing 12,12”,22 are located on the inside of the shielding wall 2221b, and the sound holes 123a,223a (second sound holes) are located on the outside of the shielding wall 2221b. This suppresses the cancellation of the acoustic signal AC1 by the acoustic signal AC2 inside the shielding wall 2221b, while allowing a portion of the acoustic signal AC1 (first acoustic signal) that leaks to the outside of the shielding wall 2221b to be canceled out by a portion of the acoustic signal AC2 emitted from the sound holes 123a,223a (second sound holes). As a result, sound leakage of the acoustic signal AC1 to the outside can be effectively suppressed without significantly reducing the listening efficiency of the acoustic signal AC1 by the user.

[0130] Furthermore, in this case, the sound pressure of the acoustic signal AC1 leaking to the outside from the openings O51 and O52 of the shielding walls 2221b and 2221b' is greater than the sound pressure of the acoustic signal AC1 leaking to the outside from the shielding walls 2221b and 2221b' other than the openings O51 and O52. Therefore, it is desirable that the opening area per unit area of ​​the sound holes 123a and 223a (second sound holes) located on the side where the openings O51 and O52 are provided is greater than the opening area per unit area of ​​the sound holes 123a and 223a (second sound holes) located on the side where the openings O51 and O52 are not provided. This makes it possible to bring the sound pressure distribution of the acoustic signal AC2 (second acoustic signal) emitted from the sound holes 123a and 223a (second sound holes) closer to the sound pressure distribution of the acoustic signal AC1 leaking to the outside of the shielding wall 2221b, and to appropriately cancel out the acoustic signal AC1 with the acoustic signal AC2. In other words, acoustic signal AC1 (first acoustic signal) is emitted from tone holes 121a and 221a (first tone holes), and acoustic signal AC2 (second acoustic signal) is emitted from tone holes 123a and 223a (second tone holes). In this case, the attenuation rate η of acoustic signal AC1 (first acoustic signal) at position P2 (second point) with respect to position P1 (first point) is 11 However, the attenuation rate η of the acoustic signal due to air propagation at position P2 (second point) relative to position P1 (first point) is 21 A predetermined value η that is smaller than th The sound pressure distribution can be balanced as follows. Alternatively, in this case, the attenuation η of the acoustic signal AC1 (first acoustic signal) at position P2 (second point) with reference to position P1 (first point) is 12 However, the attenuation of the acoustic signal due to air propagation at position P2 (second point) relative to position P1 (first point) is η 22 A predetermined value ω that is greater than th As described above, the sound pressure distribution can be balanced. Here, position P1 (first point) is a predetermined point to which the acoustic signal AC1 (first acoustic signal) emitted from the sound hole 221a (first sound hole) reaches. Also, position P2 (second point) is a predetermined point that is further from the acoustic signal output device than position P1 (first point). This effectively suppresses sound leakage.

[0131] The following describes an example in which housing 2112 is housing 12 of the first embodiment or a modified version thereof, and this housing 12 (housing 2112) is held by the mounting part 2221 of mounting method 8. However, this does not limit the present invention. Housing 2112 may be housings 12,12”,22 as exemplified in the second to fourth embodiments and their modified versions, or housings 12,12”,22 may be held by the mounting part 2221' of mounting method 9. In this case as well, the following configuration can be applied.

[0132] As illustrated in Figure 46B, the acoustic signal output device 2600 in this case has a driver unit 11 that emits an acoustic signal AC1 (first acoustic signal) to one side (direction D1) and an acoustic signal AC2 (second acoustic signal), which is the inverse phase signal of the acoustic signal AC1 (first acoustic signal) or an approximate signal of the inverse phase signal, to the other side (direction D2). As described above, the walls 121 and 123 of the housing 12 are provided with one or more sound holes 121a (first sound holes) for leading out the acoustic signal AC1 (first acoustic signal) emitted from the driver unit 11 to the outside, and one or more sound holes 123a (second sound holes) for leading out the acoustic signal AC2 (second acoustic signal) emitted from the driver unit 11 to the outside (Figures 46B and 46C). As mentioned above, sound leakage is suppressed by a portion of the acoustic signal AC2 (second acoustic signal) emitted from the sound hole 123a (second sound hole) canceling out a portion of the acoustic signal AC1 (first acoustic signal) emitted from the sound hole 121a (first sound hole). As illustrated in Figure 46B, the sound hole 121a (first sound hole) of the housing 12 is located on the inside side (D1 direction side) of the shielding wall 2221b, and the sound hole 123a (second sound hole) is located on the outside side (D2 direction side) of the shielding wall 2221b. This suppresses the cancellation of the acoustic signal AC1 by the acoustic signal AC2 inside the shielding wall 2221b, while allowing a portion of the acoustic signal AC1 (first acoustic signal) that leaks to the outside of the shielding wall 2221b to be canceled out by a portion of the acoustic signal AC2 emitted from the sound hole 123a (second sound hole). As a result, the leakage of the acoustic signal AC1 to the outside can be effectively suppressed without significantly reducing the listening efficiency of the acoustic signal AC1 by the user.

[0133] As described above, a portion of the shielding wall 2221b (the end portion 2221c side) is provided with an opening O51 that partially opens a portion of the auricle 1020 (the lower portion 1024) to the outside when the upper portion 1022 of the auricle 1020 is fitted into the inner wall surface 2221aa side of the fixing portion 2221a (Figures 46A and 46B). In other words, the opening O51 in this example is positioned to open the lower portion 1024 of the auricle 1020 to the outside when the upper portion 1022 of the auricle 1020 is fitted into the inner wall surface 2221aa side of the fixing portion 2221a. Here, the opening area per unit area of ​​the sound hole 123a (second sound hole) located on the side where the opening O51 is provided (Figure 46B) is larger than the opening area per unit area of ​​the sound hole 123a (second sound hole) located on the side where the opening is not provided (Figure 46C). In other words, as illustrated in Figures 46B, 46C, and 47A, the tone holes 123a (second tone holes) are provided along the aforementioned circumference C1. Here, we assume that the surface of the wall portion 123 of the housing 12 is equally divided into unit area regions (in this example, unit area regions C5-1 and C5-2) along the circumference C1. In this example, the number of tone holes 123a (second tone holes) located on the side where the opening portion O51 is provided (unit area region C5-1) is greater than the number of tone holes 123a (second tone holes) located on the side where the opening portion is not provided (unit area region C5-2). Therefore, the opening area per unit area located on the side where the opening portion O51 is provided (unit area region C5-1) is greater than the opening area per unit area of ​​the tone holes 123a (second tone holes) located on the side where the opening portion is not provided (unit area region C5-2). This makes it possible to bring the sound pressure distribution of the acoustic signal AC2 (second acoustic signal) emitted from the sound holes 123a, 223a (second sound holes) closer to the sound pressure distribution of the acoustic signal AC1 leaking outside the shielding wall 2221b, thereby appropriately canceling out the acoustic signal AC1 with the acoustic signal AC2 and effectively suppressing sound leakage.

[0134] In addition, as illustrated in Figure 47B, the average opening area of ​​the tone holes 123a (second tone holes) located on the side where the opening O51 is provided (unit area region C5-1) may be greater than the average opening area of ​​the tone holes 123a (second tone holes) located on the side where the opening is not provided (unit area region C5-2). Alternatively, as illustrated in Figure 48A, on the side where the opening O51 is provided (unit area region C5-1), two tone holes 123a (second tone holes) may be arranged in a direction perpendicular to the circumference C1 at equal intervals in the direction of the circumference C1, while on the side where the opening is not provided (unit area region C5-2), one tone hole 123a (second tone hole) may be arranged at equal intervals in the direction of the circumference C1. Alternatively, as illustrated in Figure 48B, the sound hole 123a (second sound hole) is located on the side where the opening O51 is provided (unit area region C5-1), but the sound hole 123a (second sound hole) does not need to be located on the side where the opening is not provided (unit area region C5-2). Even in this way, sound leakage can be effectively suppressed.

[0135] [Sixth Embodiment] In the sixth embodiment, other mounting methods for ear-mounted acoustic signal output devices are illustrated.

[0136] <Mounting method 11> As illustrated in Figure 49A, the mounting portion 2121 of the acoustic signal output device 2100 of mounting method 1 may be omitted.

[0137] <Mounting method 12> As illustrated in Figure 49B, the mounting portion 2123 of the acoustic signal output device 2100 in mounting method 1 is omitted, and the housing 2112 may be either of the aforementioned housings 12, 12”, 22. However, in this example, when the acoustic signal output device 3200 is mounted on the auricle 1020, the opening direction (D1) of the sound holes 121a, 221a of the housings 12, 12”, 22 is configured to be approximately perpendicular to the direction of the external auditory canal 1021.

[0138] <Mounting method 13> As illustrated in Figure 50A, the mounting portion 2121 of the acoustic signal output device 2300 in mounting method 5 is omitted, and the housing 2112 may be either of the aforementioned housings 12, 12”, 22. In this example, when the acoustic signal output device 3300 is mounted on the auricle 1020, the sound holes 121a, 221a of the housings 12, 12”, 22 are configured to face the external auditory canal 1021.

[0139] <Mounting method 14> As illustrated in Figure 50B, the acoustic signal output device 3600 may be configured such that the mounting portion 2221 of the acoustic signal output device 2500 of mounting method 8 is replaced by the mounting portion 2221'. The mounting portion 2221' includes a shielding wall 2221b that is configured to cover only the upper portion 1022 of the auricle 1020 when the inner wall surface side of the fixing portion 2221a is fitted onto the upper portion 1022 of the auricle 1020. Furthermore, the end portion 2221c' of the shielding wall 2221b is curved, and the area covered by the shielding wall 2221b on the helix 1022a side of the auricle 1020 is smaller than the area covered by the shielding wall 2221b on the base side of the auricle 1020.

[0140] <Mounting method 15> As illustrated in Figure 51A, the mounting portion 2122 of the acoustic signal output device 2200 of mounting method 4 may be omitted.

[0141] <Mounting method 16> As illustrated in Figure 51B, the acoustic signal output device 4100' may have a configuration in which the mounting portion 2122 of the acoustic signal output device 2200 of mounting method 4 is omitted, and a mounting portion 4421 is provided that is configured to contact the concha of the auricle 1020 when worn. One end of the mounting portion 4421 holds the housing 2112, and the other end of the mounting portion 4421 is shaped to support the concha of the auricle 1025 without obstructing the external auditory canal. This allows for more stable mounting.

[0142] <Mounting method 17> The acoustic signal output device 4200 illustrated in Figure 52A comprises a housing 2112, a columnar mounting portion 4210 that holds the housing 2112 and is configured to be positioned on the base side of the auricle 1020 when worn, and arc-shaped mounting portions 4220 that are held at both ends of the mounting portion 4210 and are mounted on the area from the back side of the upper portion 1022 to the lower portion 1024 of the auricle 1020.

[0143] <Mounting method 18> As illustrated in Figure 52B, the mounting portion 2122 of the acoustic signal output device 2200 in mounting method 4 is omitted, and the housing 2112 may be either of the aforementioned housings 12, 12, and 22. However, in this example, when the acoustic signal output device 4300 is mounted on the auricle 1020, the opening direction (D1) of the sound holes 121a and 221a of the housings 12, 12, and 22 is configured to be approximately perpendicular to the direction of the external auditory canal 1021.

[0144] <Mounting method 19> The acoustic signal output device 5110 of the mounting method 19 illustrated in Figures 53A to 53E comprises a housing 5111 that emits an acoustic signal and a mounting part 5112 that holds the housing 5111 and is designed to hook onto the back of the upper part 1022 of the auricle 1020 when worn. The mounting part 5112 is a bent rod-shaped member, and the housing 5111 is attached to one end thereof so as to be rotatable in the R5 direction. As illustrated in Figure 53E, the housing 5111 is worn without blocking the ear canal, with the sound hole from which the acoustic signal is emitted facing the ear canal. At this time, the auricle 1020 is sandwiched between the housing 5111 and the mounting part 5112, thereby fixing the acoustic signal output device 5110 to the auricle 1020. Furthermore, since the housing 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 to suit the size and shape of each individual auricle 1020.

[0145] <Mounting method 20> The acoustic signal output device 5120 of the mounting method 20 illustrated in Figures 54A to 54C has a housing 5121 that emits an acoustic signal and a mounting part 5122 that holds the housing 5121 and is of a type that hooks onto the back of the upper part 1022 of the auricle 1020 when worn. Unlike mounting method 19, the housing 5121 is not rotatable to the mounting part 5122. As illustrated in Figure 54C, the housing 5121 is worn without blocking the ear canal, with the sound hole from which the acoustic signal is emitted facing the ear canal. At this time, the auricle 1020 is sandwiched between the housing 5121 and the mounting part 5122, thereby fixing the acoustic signal output device 5120 to the auricle 1020.

[0146] <Mounting method 21> The acoustic signal output devices 5130 and 5140 of the mounting method 21 illustrated in Figures 55A and 55B each have a housing 5131 and 5141 that emits an acoustic signal, and mounting parts 5132 and 5142 that hold the housings 5131 and 5141 and are of a type that can be hooked onto the back of the upper part 1022 of the auricle 1020 when worn. Furthermore, the acoustic signal output device 5140 illustrated in Figure 55B is provided with a mounting part 5143 configured to come into contact with the concha of the auricle 1020 when worn. This enables more stable mounting.

[0147] <Mounting method 22> The acoustic signal output device 5150 illustrated in Figures 56A, 56B, and 56C comprises a housing 5151 that emits an acoustic signal, a rod-shaped mounting part 5152 that holds the housing 5151 and is designed to be hooked onto the back of the upper portion 1022 of the auricle 1020 when worn, a columnar support part 5154 that holds the housing 5151 at one end and the mounting part 5152 at the other end, a rod-shaped mounting part 5153 that is designed to be hooked onto the back of the middle portion 1023 and upper portion 1022 of the auricle 1020 from the middle portion 1023 side when worn, and a columnar support part 5155 that holds the housing 5151 at one end and the mounting part 5153 at the other end. As illustrated in Figure 56C, the housing 5151 is worn without blocking the ear canal, with the sound hole from which the acoustic signal is emitted facing the ear canal. In this process, the auricle 1020 is sandwiched between the housing 5151 and the mounting parts 5152 and 5153, thereby fixing the acoustic signal output device 5150 to the auricle 1020.

[0148] <Mounting method 23> The acoustic signal output device 5160 illustrated in Figures 57A to 57E comprises a housing 5161 that emits an acoustic signal, a columnar mounting portion 5164 that holds the housing 5161 and is configured to be positioned on the base side of the auricle 1020 when worn, a rod-shaped mounting portion 5162 that is held at one end of the mounting portion 5164 and is of the type that can be hooked onto the back side of the upper portion 1022 of the auricle 1020 when worn, and a rod-shaped mounting portion 5163 that is held at the other end of the mounting portion 5164 and is of the type that can be hooked onto the back side of the lower portion 1024 of the auricle 1020 when worn. As illustrated in Figure 57E, the housing 5161 is worn without blocking the ear canal, with the sound hole from which the acoustic signal is emitted facing the ear canal. In this process, the auricle 1020 is sandwiched between the housing 5161 and the mounting portion 5164 and mounting portions 5162 and 5163, thereby fixing the acoustic signal output device 5160 to the auricle 1020.

[0149] <Mounting method 24> The acoustic signal output devices 5170 and 5180 illustrated in Figures 58A to 58D and 59A to 59D each consist of a housing 5171 and 5181 that emits an acoustic signal, a columnar mounting portion 5172 and 5182 configured to be positioned on the back side of the intermediate portion 1023 of the auricle 1020 when worn, and a curved band-shaped support portion 5173 and 5183, one end of which holds the housing 5171 and 5181 and the other end of which holds the mounting portion 5172 and 5182. As illustrated in Figures 58D and 59D, the housings 5171 and 5181 are worn without blocking the ear canal, with the sound holes from which the acoustic signal is emitted facing the ear canal. In this process, the auricle 1020 is sandwiched between the housing 5171, 5181 and the mounting parts 5172, 5182, thereby fixing the acoustic signal output devices 5170, 5180 to the auricle 1020.

[0150] <Mounting method 25> The acoustic signal output device 5190 illustrated in Figures 60A to 60C comprises a housing 5191 that emits an acoustic signal, and a rod-shaped mounting portion 5192 that holds the housing 5191 and is configured to be positioned on the back side of the auricle 1020 when worn. The mounting portion 5192 holds the housing 5191 at one end that is positioned on the lower part 1024 side of the auricle 1020 when worn. As illustrated in Figure 60C, the housing 5191 is worn without blocking the ear canal, with the sound hole from which the acoustic signal is emitted facing the ear canal. At this time, the auricle 1020 is sandwiched between the housing 5191 and the mounting portion 5192, thereby fixing the acoustic signal output device 5190 to the auricle 1020.

[0151] <Mounting method 26> The acoustic signal output device 5200 illustrated in Figures 61A to 61E comprises a housing 5201 that emits an acoustic signal and an annular mounting portion 5202 that holds the housing 5021. As illustrated in Figure 61E, the housing 5201 is mounted without blocking the ear canal, with the sound holes from which the acoustic signal is emitted facing the ear canal. When mounted, the auricle 1020 is inserted into the annular mounting portion 5202, and the mounting portion 5202 is positioned on the back of the upper portion 1022, the middle portion 1023, and the lower portion 1024 of the auricle 1020. At this time, the auricle 1020 is sandwiched between the housing 5201 and the mounting portion 5202, thereby fixing the acoustic signal output device 5200 to the auricle 1020.

[0152] <Mounting method 27> As illustrated in Figures 62A and 64B, the acoustic signal output device may be of a type in which any of the housings 12, 12, and 22 illustrated in the first to fourth embodiments and their variations is fixed to the temples of eyeglasses.

[0153] In the acoustic signal output devices 5310 and 5320 illustrated in Figures 62A and 62B, one end of a support portion 5312 is held in the middle of the temple 5311 of the eyeglasses, and the other end of the support portion 5312 holds the housing 12. In both acoustic signal output devices 5310 and 5320, when worn, the temple 5311 of the eyeglasses is positioned behind the upper portion 1022 of the auricle 1020. However, in the acoustic signal output device 5310 illustrated in Figure 62A, when worn, the opening direction of the sound hole 121a of the housing 12 is tilted relative to the external auditory canal 1021. On the other hand, in the example of the acoustic signal output device 5320 illustrated in Figure 62B, when worn, the sound hole 121a of the housing 12 is positioned facing the external auditory canal 1021.

[0154] In the acoustic signal output devices 5340 and 5350 illustrated in Figures 63A and 63B, the housing 12 is directly held at the middle portion of the temple 5311 of the eyeglasses. In both acoustic signal output devices 5340 and 5350, when worn, the temple 5311 of the eyeglasses is positioned behind the upper portion 1022 of the auricle 1020. However, in the acoustic signal output device 5340 illustrated in Figure 63A, the housing 12 is held to the temple 5311 such that the opening direction of the sound hole 121a of the housing 12 is approximately perpendicular to the temple 5311, and when worn, the opening direction of the sound hole 121a of the housing 12 is approximately perpendicular to the external auditory canal 1021. On the other hand, in the acoustic signal output device 5350 illustrated in Figure 63B, the housing 12 is held on the temple 5311 such that the opening direction of the sound hole 121a of the housing 12 is substantially parallel to the temple 5311, and when worn, the opening direction of the sound hole 121a of the housing 12 faces the upper part 1022 of the auricle 1020.

[0155] The acoustic signal output devices 5360 and 5370 illustrated in Figures 64A and 64B directly hold the housing 12 at the tips of the eyeglass temples 5361 and 5371. In both acoustic signal output devices 5360 and 5370, when worn, the eyeglass temples 5361 are positioned behind the upper portion 1022 of the auricle 1020. However, in the acoustic signal output device 5360 illustrated in Figure 64A, when worn, the opening direction of the sound hole 121a of the housing 12 is directed from the base of the lower portion 1024 of the auricle 1020 towards the external auditory canal 1021. In the acoustic signal output device 5370 illustrated in Figure 64B, when worn, the opening direction of the sound hole 121a of the housing 12 is directed from the outside of the lower portion 1024 of the auricle 1020 towards the external auditory canal 1021.

[0156] <Mounting method 28> In addition, as illustrated in Figure 65A, the acoustic signal output device 5380 may have a rod-shaped mounting portion 5381 curved to fit the neck or shoulder of the user 1000, to which any of the housings 12, 12, and 22 illustrated in the first to fourth embodiments and their modified versions may be fixed. Also, as illustrated in Figure 65B, the acoustic signal output device 5390 may have a rod-shaped mounting portion 5391 curved to fit the top of the user 1000's head, to which any of the housings 12, 12, and 22 may be fixed. Furthermore, as illustrated in Figure 65C, the acoustic signal output device 5400 may have a rod-shaped mounting portion 5401 curved to fit the back of the user 1000's head and auricle 1020, to which any of the housings 12, 12, and 22 may be fixed.

[0157] <Other mounting methods> In addition, existing open-ear type earphone mounting methods may be applied to the acoustic signal output devices 4, 4', 10, 20, 30 exemplified in the first to fourth embodiments and their variations. For example, as exemplified in Reference 1 (https: / / www.sony.jp / headphone / products / STH40D / feature_1.html), a ring-shaped stopper may be added to the D1 direction side of the housings 12, 12”, 22 or the acoustic signal output units 40-1, 40-2, and a U-shaped mounting part may be added to the side opposite to the D1 direction of the housings 12, 12”, 22 or the acoustic signal output units 40-1, 40-2. In this case, the ring-shaped body is placed against the peripheral part of the external auditory canal (for example, the concha), and the lower part of the auricle is sandwiched between the U-shaped mounting portion, thereby attaching the housing 12, 12, 22 or the acoustic signal output unit 40-1, 40-2 to the auricle. In particular, when applying the mounting method of Reference 1 to the acoustic signal output device 20 of the second embodiment, a ring-shaped body acting as a stopper is added to the D1 direction side of the housing 22, and the U-shaped mounting portion added to the D2 direction side of the housing 22 serves as both the waveguide 24, 25 and the housing 23 (Figure 20).

[0158] For example, as illustrated in Reference 2 (https: / / www.bose.com / en_us / products / headphones / earbuds / sport-open-earbuds.html#v=sport_open_earbuds_black), the housings 12, 12”, 22 or the acoustic signal output units 40-1, 40-2 may be shaped like elliptical columns, and a J-shaped attachment portion may be provided on the housings 12, 12”, 22 or the acoustic signal output units 40-1, 40-2. In this case, the housings 12, 12”, 22 or the acoustic signal output units 40-1, 40-2 are attached to the auricle by placing the D1 direction side of the housings 12, 12”, 22 or the acoustic signal output units 40-1, 40-2 against the front side (external auditory canal side) of the upper part of the auricle, and hooking the J-shaped attachment portion onto the back side of the upper part of the auricle.

[0159] For example, as illustrated in Reference 3 (https: / / ambie.co.jp / soundearcuffs / tws / ), the housing 12, 12”, 22 or the acoustic signal output unit 40-1, 40-2 may be configured in a substantially spherical shape, and the side of the housing 12, 12”, 22 or the acoustic signal output unit 40-1, 40-2 opposite to the D1 direction may be held by one end of a C-shaped mounting part. The other end of this C-shaped mounting part may also be configured in a substantially spherical shape. In this case, the housing 12, 12”, 22 or the acoustic signal output unit 40-1, 40-2 is attached to the auricle by placing the D1 direction side of the housing 12, 12”, 22 or the acoustic signal output unit 40-1, 40-2 against the peripheral part of the external auditory canal (e.g., the concha) and gripping (clamping) the middle part of the auricle with the C-shaped mounting part.

[0160] For example, as illustrated in Reference 4 (https: / / www.jabra.jp / bluetooth-headsets / jabra-elite-active-45e##100-99040000-40), sound tubes may be added to the sound holes 121a, 221a of the housings 12, 12”, 22 or the acoustic signal output sections 40-1, 40-2 to direct the acoustic signals emitted from the sound holes 121a, 221a towards the external auditory canal.

[0161] For example, as illustrated in Reference 5 (https: / / www.audio-technica.co.jp / product / ATH-EW9), a semicircular mounting part (ear hanger) equipped with an adjustment mechanism (slide-fit mechanism) for adjusting the position of the mounted housing 12, 12”, 22 or acoustic signal output unit 40-1, 40-2 relative to the auricle may be provided. In this case, the housing 12, 12”, 22 or acoustic signal output unit 40-1, 40-2 is mounted on the auricle by placing the D1 direction side of the housing 12, 12”, 22 or acoustic signal output unit 40-1, 40-2 against the front side of the upper part of the auricle and hooking the semicircular mounting part onto the back side of the upper part of the auricle. In this state, the position of the mounted housing 12, 12”, 22 or acoustic signal output unit 40-1, 40-2 relative to the auricle can be adjusted by operating the adjustment mechanism.

[0162] For example, as illustrated in Reference 6 (https: / / www.mu6.live / ), a headband-type mounting part may be provided on the housing 12, 12”, 22 or the acoustic signal output unit 40-1, 40-2. For example, both ends of the headband-type mounting part may hold the housing 12, 12”, 22 or the acoustic signal output unit 40-1, 40-2. In this case, the housing 12, 12”, 22 or the acoustic signal output unit 40-1, 40-2 may be rotatable relative to both ends of the headband-type mounting part. In this case, the D1 direction side of the housing 12, 12”, 22 or the acoustic signal output unit 40-1, 40-2 is placed against the auricle or near the auricle, and the headband-type mounting part is attached to the head. In this case, by rotating the housing 12, 12”, 22 or the acoustic signal output unit 40-1, 40-2 relative to the headband-type mounting part, the mounting position of the headband-type mounting part and the position of the housing 12, 12”, 22 or the acoustic signal output unit 40-1, 40-2 relative to the auricle can be adjusted.

[0163] [Other variations, etc.] It should be noted that the present invention is not limited to the embodiments described above. For example, the embodiments and their modifications described above show examples of applying the present invention to acoustic listening devices that are worn on the ear without sealing the user's ear canal (e.g., open-ear earphones, headphones, etc.). However, this does not limit the present invention, and the present invention may also be applied to acoustic listening devices that are worn on body parts other than the ear without sealing the user's ear canal, such as bone conduction earphones and neck speaker earphones.

[0164] Furthermore, for example, the present invention may be used as an acoustic signal output device capable of controlling the attenuation rate of acoustic signals emitted to the outside without providing sound-absorbing material in the sound holes through which acoustic signals emitted from the driver unit pass. Also, for example, the present invention may be used as an acoustic signal output device capable of attenuating acoustic signals emitted from a driver unit so that they cannot be heard at a predetermined location, without performing directional control by physical shape or signal processing. Also, for example, the present invention may be used as an acoustic signal output device capable of attenuating acoustic signals at a point without placing a speaker at that point. Also, for example, the present invention may be used as an acoustic signal output device capable of locally reproducing acoustic signals in a specific local area without covering the area around that local area with sound-absorbing material. [Explanation of symbols]

[0165] 4, 4', 10, 20, 30, 2100-2600, 3100-3300, 3600, 4100-4300, 5110-5200, 5310-5400 Acoustic signal output device 11 Driver Units 113 Vibration plate 12,12”,22,23,2112,5021,5111,5121,5131,5151,5161,5171,5191,5201 case 121a,123a,221a,223a sound hole 13 Sound-absorbing material 24,25 Waveguide 31,41 Circuit section 40-1, 40-2 Audio signal output section AC1,AC2 acoustic signal AR21,AR22 hollow part C1 Circumference C1-1, C1-2, C1-3, C1-4 Unit circular arc region MAC1, MAC2 Monoaural Audio Signal 2121,2122,2123,2124,2221,2224,4210,4220,4421,5112,5122,5132,5152,5153,5162,5163,5164,5172,5192,5202,5381,5391,5401 Mounting part 2121a,2122a,2123a,2124a,2221a Fixed part 2221b Shielding Wall

Claims

1. An acoustic signal output device, Multiple driver units, One or more first sound holes for leading out a first sound signal emitted from any of the driver units to the outside, and one or more second sound holes for leading out a second sound signal emitted from any of the driver units to the outside, It has one or more third sound holes for guiding a third acoustic signal emitted from any of the driver units to the outside, and one or more fourth sound holes for guiding a fourth acoustic signal emitted from any of the driver units to the outside, The first tone hole is open facing the first direction, The second tone hole is open facing a second direction between the first direction and the direction opposite to the first direction. The fourth tone hole is open facing the same or approximate fourth direction as the first direction. The acoustic signal output device wherein the third sound hole is open facing a third direction between the fourth direction and the direction opposite to the fourth direction.

2. The first tone hole and the second tone hole are located in the first housing. The third and fourth tone holes are installed in the second housing. The acoustic signal output device according to claim 1.

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