Acoustic signal output device

Abstract

To provide an ear-mounted acoustic signal output device which can be stably mounted with a small burden on the ear.SOLUTION: There is provided an acoustic signal output device including a housing, a curved mounting portion to which the housing is fixed, a driver unit accommodated in the housing, a first end surface disposed on one side of the driver unit, a second end surface disposed on the other side of the driver unit, and a side surface surrounding a space sandwiched between the first end surface and the second end surface around a virtual axis passing through the first end surface and the second end surface. The driver unit is configured to emit a first acoustic signal to the one side and emit a second acoustic signal to the other side, the second acoustic signal being an antiphase signal of the first acoustic signal or an approximate signal of the antiphase signal, the driver unit has a substantially cylindrical shape and includes a first sound hole that guides the first acoustic signal to the outside and a second sound hole that emits the second acoustic signal to the outside, the first sound hole is provided in the first end surface, and the second sound hole is provided in the side surface.SELECTED DRAWING: Figure 65

Description

[Technical Field]

[0001] The present invention relates to an acoustic signal output device, and more particularly to an ear-mounted acoustic signal output device. [Background technology]

[0002] In recent years, increased strain on the ears caused by ear-worn acoustic signal output devices such as earphones and headphones has become a problem. Under these circumstances, in addition to conventional acoustic signal output devices that block the ear canal when worn, open-ear acoustic signal output devices that do not seal the ear canal are also known as devices that reduce strain on the ears (see, for example, Non-Patent Document 1, etc.). [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> Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional open-ear type acoustic signal output devices have the problem of placing a heavy burden on the ears.

[0005] The present invention has been made in view of the above points, and has as its object to provide an acoustic signal output device that puts less strain on the ears and can suppress sound leakage to the surroundings. [Means for solving the problem]

[0006] An acoustic signal output device is provided, the acoustic signal output device having a housing, a curved mounting portion to which the housing is fixed, a driver unit housed in the housing, a first end face arranged on one side of the driver unit, a second end face arranged on the other side of the driver unit, and a side face surrounding a space sandwiched between the first end face and the second end face, with a virtual axis passing through the first end face and the second end face as its center. The driver unit is configured to emit a first acoustic signal to one side and emit a second acoustic signal that is an inverse phase signal of the first acoustic signal or a signal approximate to the inverse phase signal to the other side, the driver unit is substantially cylindrical and has a first sound hole that guides the first acoustic signal to the outside and a second sound hole that guides the second acoustic signal to the outside, the first sound hole being provided in the first end face and the second sound hole being provided in the side face. [Effects of the Invention]

[0007] Such an acoustic signal output device places less strain on the ears and can be worn stably. [Brief explanation of the drawings]

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

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, a basic configuration of an audio signal output device will be illustrated, and then a wearing method of the audio signal output device that puts less strain on the ears and allows stable wearing will be illustrated. [First embodiment] First, a first embodiment of the present invention will be described. <Configuration> The acoustic signal output device 10 of this embodiment is a device for listening to sound (for example, open-ear 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> Driver unit (speaker driver unit) 11 is a device (device with speaker functionality) that emits (sounds) an acoustic signal AC1 (first acoustic signal) based on an input output signal to one side (D1 direction), and emits an acoustic signal AC2 (second acoustic signal) that is an inverse phase signal (phase-inverted signal) of acoustic signal AC1 or a signal approximating the inverse phase signal to the other side (D2 direction). That is, the acoustic signal emitted from driver unit 11 to one side (D1 direction) will be referred to as acoustic signal AC1 (first acoustic signal), and the acoustic signal emitted from driver unit 11 to the other side (D2 direction) will be referred to as acoustic signal AC2 (second acoustic signal). For example, driver unit 11 includes diaphragm 113 that vibrates to emit acoustic signal AC1 in the D1 direction from one surface 113a, and emits acoustic signal AC2 in the D2 direction from the other surface 113b (FIG. 2B). In this example, driver unit 11 emits acoustic signal AC1 from one surface 111 in the direction D1, as diaphragm 113 vibrates based on an input output signal, and emits acoustic signal AC2, which is an inverse phase signal of acoustic signal AC1 or a signal approximating the inverse phase signal, from the other surface 112 in the direction D2. In other words, acoustic signal AC2 is emitted secondarily in conjunction with the emission of acoustic signal AC1. Note that the D2 direction (other side) is, for example, the opposite direction to the D1 direction (one side), but the D2 direction does not need to be strictly the opposite direction of the D1 direction as long as 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 driver unit 11. Also, depending on the type and shape of driver unit 11, acoustic signal AC2 may be strictly an inverse phase signal of acoustic signal AC1, or acoustic signal AC2 may be a signal approximating the inverse phase signal of acoustic signal AC1. For example, the approximation signal of the opposite phase signal of acoustic signal AC1 may be (1) a signal obtained by shifting the phase of the opposite phase signal of acoustic signal AC1, (2) a signal obtained by changing (amplifying or attenuating) the amplitude of the opposite phase signal of acoustic signal AC1, or (3) a signal obtained by shifting the phase of the opposite phase signal of acoustic signal AC1 and further changing the amplitude.The phase difference between the antiphase signal of acoustic signal AC1 and its approximation signal is preferably δ1% or less of one cycle of the antiphase signal of acoustic signal AC1. Examples of δ1% include 1%, 3%, 5%, 10%, and 20%. The difference between the amplitude of the antiphase signal of acoustic signal AC1 and the amplitude of its approximation signal is preferably δ2% or less of the amplitude of the antiphase signal of acoustic signal AC1. Examples of δ2% include 1%, 3%, 5%, 10%, and 20%. Examples of the type of driver unit 11 include a dynamic type, a balanced armature type, a hybrid type of a dynamic type and a balanced armature type, and an electrostatic type. The shapes of driver unit 11 and diaphragm 113 are not limited. For simplicity of explanation, this embodiment illustrates an example in which the driver unit 11 has an outer shape that is approximately cylindrical with both end faces, and the diaphragm 113 has an approximately disc shape. However, this does not limit the present invention. For example, the driver unit 11 may have an outer shape that is a rectangular parallelepiped, or the diaphragm 113 may have a dome shape. Examples of audio signals include music, voice, sound effects, and environmental sounds.

[0011] <Case 12> Housing 12 is a hollow member with an outer wall, and houses driver unit 11 inside. For example, driver unit 11 is fixed to the end of housing 12 on the D1 direction side. However, this does not limit the present invention. There are no limitations on the shape of housing 12, but it is desirable that the shape of housing 12 be rotationally symmetric (line symmetric) or approximately rotationally symmetric about axis A1 extending along the D1 direction. This makes it easy to provide sound hole 123a (described in detail below) so as to reduce the variation in the energy of the sound emitted from housing 12 between directions. As a result, it becomes easy to reduce sound leakage uniformly in all directions. For example, housing 12 has a first end face that is wall portion 121 arranged on one side (D1 direction side) of driver unit 11, a second end face that is wall portion 122 arranged on the other side (D2 direction side) of driver unit 11, and a side face that is wall portion 123 that surrounds the space between the first end face and the second end face, with axis A1 passing through the first end face and the second end face as the center (FIGS. 2B and 3B). In this embodiment, for simplicity of explanation, an example is shown in which housing 12 has a substantially cylindrical shape with both end faces. For example, the distance between wall portion 121 and wall portion 122 is 10 mm, and wall portions 121 and 122 are circular with a radius of 10 mm. However, these are merely examples and do not limit the present invention. For example, housing 12 may have a substantially dome shape with walls at the ends, a hollow substantially cubic shape, or any other three-dimensional shape. Furthermore, there are no limitations on the material that constitutes housing 12. The housing 12 may be made of a rigid body such as synthetic resin or metal, or may be made of an elastic body such as rubber.

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

[0013] The acoustic signal AC1 emitted from the sound hole 121a reaches the ear canal of the user and is heard by the user. On the other hand, an acoustic signal AC2, which is an inverse phase signal of the acoustic signal AC1 or an approximation of the inverse phase signal, is emitted from the sound hole 123a. A part of this acoustic signal AC2 cancels out a part (sound leakage component) of the acoustic signal AC1 emitted from the sound hole 121a. That is, by emitting the acoustic signal AC1 (first acoustic signal) from the sound hole 121a (first sound hole) and emitting the acoustic signal AC2 (second acoustic signal) from the sound hole 123a (second sound hole), the attenuation rate η of the acoustic signal AC1 (first acoustic signal) at the position P2 (second position) relative to the position P1 (first position) becomes 11 Set a predetermined value η th The attenuation amount η of the acoustic signal AC1 (first acoustic signal) at the position P2 (second position) based on the position P1 (first position) can be expressed as follows: 12 a predetermined value ω th Here, the position P1 (first point) is a predetermined point where the acoustic signal AC1 (first acoustic signal) emitted from the sound hole 121a (first sound hole) arrives. On the other hand, the position P2 (second point) is a predetermined point that is farther from the acoustic signal output device 10 than the position P1 (first point). The predetermined value η th is the attenuation rate η of any or specific acoustic signal (sound) due to air propagation at position P2 (second position) relative to position P1 (first position). 21 In addition, the predetermined value ω this the attenuation of any or specific acoustic signal (sound) due to air propagation at position P2 (second point) relative to position P1 (first point), η 22 That is, the acoustic signal output device 10 of this embodiment has an attenuation rate η 11 is the decay rate η 21 A predetermined value η smaller than th It is designed to be equal to or less than the attenuation η 12 is the attenuation η 22 a predetermined value ω greater than th The acoustic signal AC1 is propagated through the air from position P1 to position P2, and is attenuated due to this air propagation and the acoustic signal AC2. The attenuation rate η 11 is the ratio (AMP2(AC1) / AMP1(AC1)) of the magnitude AMP2(AC1) of the acoustic signal AC1 at the position P2 attenuated due to air propagation and the acoustic signal AC2 to the magnitude AMP1(AC1) of the acoustic signal AC1 at the position P1. Also, the attenuation amount η 12 is the difference between the magnitude AMP1(AC1) and the magnitude AMP2(AC1) (|AMP1(AC1)-AMP2(AC1)|). On the other hand, if the acoustic signal AC2 is not assumed, an arbitrary or specific acoustic signal AC propagating through the air from the position P1 to the position P2 ar is attenuated due to air propagation, not due to the acoustic signal AC2. 21 is the acoustic signal AC at position P1 ar The size of AMP1 (AC ar ) at position P2, which is attenuated due to air propagation (attenuation without being attributable to acoustic signal AC2) ar Size of AMP2 (AC ar ) ratio (AMP2(AC ar ) / AMP1(AC ar )) Also, the attenuation η 22 is the magnitude AMP1(AC ar ) and size AMP2(AC ar ) and the difference (|AMP1(AC ar )-AMP2(AC ar)|). Examples of the magnitude of an acoustic signal include the sound pressure of the acoustic signal or the energy of the acoustic signal. Furthermore, the "sound leakage component" refers to, for example, a component of the acoustic signal AC1 emitted from the sound hole 121a that is likely to reach an area other than that of 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, the "sound leakage component" refers to a component of the acoustic signal AC1 that propagates in a direction other than direction D1. For example, the direct wave of the acoustic signal AC1 is mainly emitted from the sound hole 121a, and the direct wave of the second acoustic signal is mainly emitted from the second sound hole. A portion of the direct wave of the acoustic signal AC1 emitted from the sound hole 121a (the 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 hole 123a. However, this does not limit the present invention, and this cancellation can occur with waves other than direct waves. That is, the sound leakage component, which is at least one of the direct wave and the reflected wave of the acoustic signal AC1 emitted from the sound hole 121a, may be canceled out by at least one of the direct wave and the reflected wave of the acoustic signal AC2 emitted from the sound hole 123a, thereby suppressing sound leakage.

[0014] The arrangement of the sound holes 121a and 123a is shown below. Sound hole 121a (first sound hole) in this embodiment is provided in area AR1 (first area) of wall portion 121 arranged on one side of driver unit 11 (the D1 direction side, which is the side from which acoustic signal AC1 is emitted) (FIGS. 1, 2A, 2B, 3B). That is, sound hole 121a opens facing in direction D1 (first direction) along axis A1. Furthermore, sound hole 123a (second sound hole) in this embodiment is provided in area AR3 of wall portion 123 that contacts area AR between area AR1 (first area) of wall portion 121 of housing 12 and area AR2 (second area) of wall portion 122 arranged on the D2 direction side of driver unit 11 (the other side, which is the side from which acoustic signal AC2 is emitted). That is, if the center of the housing 12 is used as a reference and the direction between the D1 direction (first direction) and the direction opposite to the D1 direction is defined as the D12 direction (second direction) (Figure 3B), the sound hole 121a (first sound hole) is provided on the D1 direction side (first direction side) of the housing 12, and the sound hole 123a (second sound hole) is provided on the D12 direction side (second direction side) of the housing 12. For example, when housing 12 has a first end face that is wall portion 121 arranged on one side (D1 direction side) of driver unit 11, a second end face that is wall portion 122 arranged on the other side (D2 direction side) of driver unit 11, and a side face that is wall portion 123 that surrounds the space between the first end face and the second end face, centered on axis A1 that runs along the emission direction (D1 direction) of acoustic signal AC1 that passes through the first end face and the second end face (FIGS. 2B and 3B), sound hole 121a (first sound hole) is provided in the first end face, and sound hole 123a (second sound hole) is provided in the side face. In this embodiment, no sound hole is provided on the wall portion 122 side of housing 12. If a sound hole were provided on the wall portion 122 side of housing 12, the sound pressure level of acoustic signal AC2 emitted from housing 12 would exceed the level necessary to offset the sound leakage component of acoustic signal AC1, and this excess would be perceived as sound leakage.

[0015] As illustrated in FIG. 2A and other figures, sound hole 121a of this embodiment is disposed on or near axis A1 along the emission direction (D1 direction) of acoustic signal AC1. Axis A1 of this embodiment passes through the center of region AR1 (first region) of wall 121 disposed on one side (D1 direction side) of driver unit 11 of housing 12 or near the center. For example, axis A1 is an axis extending in the D1 direction through the central region of housing 12. That is, sound hole 121a of this embodiment is provided at the center position of region AR1 of wall 121 of housing 12. For simplicity of explanation, this embodiment shows an example in which the edge of the open end of sound hole 121a has a circular shape (the open end is circular). The radius of such sound hole 121a is, for example, 3.5 mm. However, this does not limit the present invention. For example, the edge of the open end of sound hole 121a may have another shape, such as an ellipse, a rectangle, or a triangle. 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 a plurality of holes. Furthermore, in this embodiment, for the sake of simplicity of explanation, an example is shown in which one sound hole 121a is provided in the area AR1 (first area) of the wall 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 the area AR1 (first area) of the wall 121 of the housing 12.

[0016] It is desirable that the sound hole 123a (second sound hole) of this embodiment be arranged in consideration of the following points, for example. (1) Positional viewpoint: The sound hole 123a is positioned so that the propagation path of the sound leakage component of the sound signal AC1 to be cancelled overlaps with the propagation path of the sound signal AC2 emitted from the sound hole 123a. (2) Area perspective: The propagation area of ​​acoustic signal AC2 emitted from sound hole 123a and the frequency characteristics of housing 12 vary depending on the opening area of ​​sound hole 123a. Furthermore, the frequency characteristics of housing 12 affect the frequency characteristics of acoustic signal AC2 emitted from sound hole 123a, i.e., the amplitude at each frequency. Taking into consideration the propagation area and frequency characteristics of acoustic signal AC2 emitted from sound hole 123a, the opening area of ​​sound hole 123a is determined so that the sound leakage components are canceled out by acoustic signal AC2 emitted from sound hole 123a in the area where they are to be canceled out. From the above viewpoint, it is desirable that the sound hole 123a (second sound hole) be configured as follows, for example. For example, as illustrated in FIGS. 2B, 3A, and 3C, it is desirable that a plurality of sound holes 123a (second sound holes) in this embodiment are provided along a circumference (circle) C1 centered on an axis A1 along the emission direction of the acoustic signal AC1 (first acoustic signal). When a plurality of sound holes 123a are provided along the circumference C1, the acoustic signal AC2 is emitted radially from the sound holes 123a to the outside (radially from the axis A1). Here, the sound leakage component of the acoustic signal AC1 is also emitted radially from the sound holes 123a to the outside (radially from the axis A1). Therefore, by providing a plurality of 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 simplicity of explanation, an example in which a plurality of sound holes 123a are provided on the circumference C1 is shown. However, it is sufficient that the plurality of sound holes 123a are provided along the circumference C1, and it is not necessary that all of the sound holes 123a are arranged strictly on the circumference C1.

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

[0018] More preferably, the multiple sound holes 123a are desirably arranged 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 arranged along the circumference C1 with the same shape, size, and spacing. When multiple sound holes 123a are arranged along the circumference C1 with the same shape, size, and spacing, the sound leakage component of the acoustic signal AC1 can be more appropriately canceled out by the acoustic signal AC2. However, this does not limit the present invention.

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

[0020] In this embodiment, for the sake of simplicity, the edge of the open end of sound hole 123a is shaped like a rectangle (the open end is square), but this does not limit the present invention. For example, the edge of the open end of sound hole 123a may be shaped like a circle, ellipse, triangle, or other shape. The open end of sound hole 123a may also be mesh-like. In other words, the open end of sound hole 123a may be composed of multiple holes. There is also no limitation on the number of sound holes 123a; either a single sound hole 123a or multiple sound holes 123a may be provided in area AR3 of wall 123 of housing 12.

[0021] It is desirable that the ratio S2 / S1 of the sum S2 of the opening areas of the sound holes 123a (second sound holes) to the sum S1 of the opening areas of the sound holes 121a (first sound holes) satisfies 2 / 3≦S2 / S1≦4 (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.

[0022] Sound leakage suppression performance may also depend on the ratio between the area of ​​wall portion 123 in which sound hole 123a is provided and the opening area of ​​sound hole 123a. For example, consider a case in which housing 12 has a first end face which is wall portion 121 arranged on one side (D1 direction side) of driver unit 11, a second end face which is wall portion 122 arranged on the other side (D2 direction side) of driver unit 11, and a side face which is wall portion 123 that surrounds the space sandwiched between the first end face and the second end face, with axis A1 along the emission direction (D1 direction) of acoustic signal AC1 that passes through the first end face and the second end face as the center, and sound hole 121a (first sound hole) is provided in the first end face and sound hole 123a (second sound hole) is provided in the side face (FIGS. 2B and 3B). In such a case, it is desirable that the ratio S2 / S3 of the total opening area S2 of the sound holes 123a to the total area S3 of the side surfaces be 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> FIG. 5A illustrates an example of how the acoustic signal output device 10 is used. In the example of FIG. 5A, one acoustic signal output device 10 is worn in each of the right ear 1010 and left ear 1020 of a user 1000. Any suitable wearing mechanism is used to wear the acoustic signal output devices 10 in the ears. The D1 direction of each acoustic signal output device 10 faces the user 1000. An 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 an acoustic signal AC1 in the D1 direction and an acoustic signal AC2 to the other side. The 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 the user 1000. Meanwhile, an acoustic signal AC2, which is an inverse phase signal of the acoustic signal AC1 or a signal approximating the inverse phase signal, is emitted from the sound hole 123a. This part of the acoustic signal AC2 cancels out the part (sound leakage component) of the acoustic signal AC1 emitted from the sound hole 121a.

[0024] <Experimental Results> The following shows the results of an experiment demonstrating the sound leakage suppression effect of the acoustic signal output device 10 of this embodiment. In this experiment, as shown in Fig. 5B, the acoustic signal output device 10 was attached to both ears of a dummy head 1100 simulating a human head, and acoustic signals were observed at positions P1 and P2. In this example, position P1 is located near the left ear 1120 of the dummy head 1100 (near the acoustic signal output device 10), and position P2 is located 15 cm outward from position P1.

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

[0026] 9A illustrates the relationship between the ratio S2 / S1 of the total opening area S2 of the sound holes 123a (second sound holes) to the total opening area S1 of the sound holes 121a (first sound holes), 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 represents the ratio S2 / S1, and the vertical axis represents the sound pressure level (SPL) [dB] representing the difference. r12h6 illustrates the results when there are six sound holes 121a and four sound holes 123a, r12h12 illustrates the results when there are twelve sound holes 121a and four sound holes 123a, and r45h35 illustrates the results when there is one sound hole 121a and four sound holes 123a. 9A, it can be seen that the difference in sound pressure between the acoustic signal observed at position P1 and the acoustic signal observed at position P2 is particularly large when the ratio S2 / S1 of the sum S2 of the opening areas of sound holes 123a to the sum S1 of the opening areas of sound holes 121a is in the range of 2 / 3≦S2 / S1≦4. This indicates that the sound leakage suppression effect is large in this range. FIG. 9B illustrates the relationship between the ratio S2 / S3 of the sum S2 of the opening areas of the sound holes 123a (second sound holes) to the total area S3 of the side surfaces 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 represents the ratio S2 / S3, and the vertical axis represents the sound pressure level (SPL) [dB] representing the difference. The meanings of r12h6, r12h12, and r45h35 are the same as in FIG. 9A. As illustrated in FIG. 9B, when the ratio S2 / S3 of the sum S2 of the opening areas of the sound holes 123a (second sound holes) to the total area S3 of the side surfaces is in the range of 1 / 20≦S2 / S3≦1 / 5, 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. This indicates that the sound leakage suppression effect is significant in this range.

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

[0028] Even in such a case, when the circumference C1 is equally divided into a plurality of unit arc regions, it is preferable that the sum of the opening areas of the sound holes 123a (second sound holes) provided along a first arc region, which is one of the unit arc regions, is the same or approximately the same as the sum of the opening areas of the sound holes 123a provided along a second arc region, which is one of the unit arc regions excluding the first arc region.It is more preferable that the sums of the opening areas of the sound holes 123a provided along each unit arc region for each unit arc region are all the same or approximately the same. For example, as illustrated in Figures 10A, 10B, 11A, and 11B, the number and size of the sound holes 123a provided in each unit arc area C1-1, C1-2, C1-3, and C1-4 are different from one another, but it is desirable that the sum of the opening areas of the sound holes 123a provided in unit arc area C1-1, the sum of the opening areas of the sound holes 123a provided in unit arc area C1-2, the sum of the opening areas of the sound holes 123a provided in unit arc area C1-3, and the sum of the opening areas of the sound holes 123a provided in unit arc area C1-4 are all the same or approximately the same.

[0029] It is sufficient that the plurality of sound holes 123a are arranged along the circumference C1, and it is not necessary that all of the sound holes 123a are arranged strictly on the circumference C1. For example, as shown in Figures 12A, 12B, and 12C, it is not necessary that all of the sound holes 123a are arranged on the circumference C1, and it is sufficient that these plurality of sound 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 it is sufficient that the position is on a circumference centered on the axis A1.

[0030] Furthermore, as long as a sufficient sound leakage suppression effect can be obtained, all sound holes 123a do not have to be arranged along circumference C1. In other words, some sound holes 123a may be arranged at positions that are off circumference C1. Also, as long as a sufficient sound leakage suppression effect can be obtained, there is no limit to the number of sound holes 123a, and only one sound hole 123a may be provided.

[0031] [Modification 2 of the First Embodiment] In the first embodiment, a configuration was exemplified in which one sound hole 121a was arranged in the center position (hereinafter simply referred to as the "center position") of area AR1 of wall 121 of housing 12 (the area of ​​the wall arranged on one side of the driver unit). However, multiple sound holes 121a may be provided in area AR1 of wall 121 of housing 12, or sound hole 121a may be biased to an eccentric position displaced from the center (center position) of area AR1 of wall 121 of housing 12. For example, as exemplified in FIG. 13A, one sound hole 121a may be provided in an eccentric position on area AR1 (a position on axis A12 that is displaced from axis A1 and is parallel to axis A1) (hereinafter simply referred to as the "eccentric position"). In other words, the position of one sound hole 121a provided in area AR1 may be biased to an eccentric position. Alternatively, as illustrated in FIG. 13B, multiple sound holes 121a may be provided in region AR1, and these multiple sound holes 121a may be offset from axis A1 and offset to an eccentric position 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 an eccentric position. That is, a single sound hole 121a may be provided, or multiple sound holes 121a may be provided, and the sound hole 121a may be offset to the center of region AR1 of wall 121 of housing 12, or may be offset to an eccentric position. Note that there is no limitation on the distance between axis A1 and axis A12, and it may 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 the area AR1 (e.g., 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 the area AR1. For example, as the frequencies of the acoustic signals AC1 and AC2 increase, their wavelengths become shorter, making it more difficult to align the phases so that the sound leakage component of the acoustic signal AC1 emitted to the outside is canceled out by the acoustic signal AC2. As a result, the higher the frequencies of the acoustic signals AC1 and AC2, the more difficult it is to suppress sound leakage of the acoustic signal AC1. Because the sound pressure levels of the acoustic signals AC1 and AC2 increase at the resonant frequency of the housing 12, if the resonant frequency of the housing 12 falls within a high frequency band where sound leakage is difficult to suppress, sound leakage will be perceived as significant. To solve this problem, the resonance frequency of the housing 12 may be controlled by setting the arrangement of the sound holes 121a as in Examples 2-1 and 2-2 below.

[0033] <Example 2-1> The arrangement of the sound holes 121a may be set so that the human hearing sensitivity to the resonant frequency of the housing 12 is reduced in the high frequency band where it is difficult to suppress sound leakage. For example, in the case of a housing 12 in which the position of the sound holes 121a is shifted to a certain eccentric position, th The human hearing sensitivity (ease of hearing) for acoustic signals with a resonant frequency above S d In addition, the predetermined frequency f of the housing 12 in which the sound hole 121a is provided at the center position is th The human hearing sensitivity to acoustic signals above the resonant frequency is S c In this case, the hearing sensitivity S d is hearing sensitivity S c That is, the predetermined frequency f of the housing 12 in which the position of the sound hole 121a (first sound hole) is biased to a certain eccentric position (a position shifted from the center of the area of ​​the wall portion arranged on one side of the driver unit) is lower than th Human hearing sensitivity S to acoustic signals above the resonant frequency dis the predetermined frequency f of the housing 12 when it is assumed that the sound hole 121a is provided at the center position (the center of the area of ​​the wall portion arranged on one side of the driver unit). th Human hearing sensitivity S to acoustic signals above the resonant frequency c The position of the sound hole 121a may be shifted to such an eccentric position. The hearing sensitivity may be any index that indicates how easily a sound is heard. The higher the hearing sensitivity, the easier it is to hear. An example of hearing sensitivity is the reciprocal of the sound pressure level of a sound that is required for a human to perceive a sound of a standard loudness. For example, the hearing sensitivity is the reciprocal of the sound pressure level at each frequency on an equal loudness curve. At a predetermined frequency f th The predetermined frequency f is the lower limit of a frequency band including a frequency at which it becomes difficult to cancel out the sound leakage component of the acoustic signal AC1 with the acoustic signal AC2. th Examples are 3000Hz, 4000Hz, 5000Hz, 6000Hz, etc.

[0034] <Example 2-2> Depending on the arrangement of the sound hole 121a, the resonance peak of the magnitude of the acoustic signal AC1 and / or the acoustic signal AC2 emitted from the housing 12 may be accentuated. For example, if the position of the sound hole 121a of the housing 12 is shifted to a certain eccentric position, the magnitude of the acoustic signal AC1 emitted from the sound hole 121a and / or the acoustic signal AC2 emitted from the sound hole 123a may be accentuated at a predetermined frequency f th The sharpness of the peak (sharpness) above is Q d In addition, the sound hole 121a of the housing 12 is provided at the center, and the sound signal AC1 emitted from the sound hole 121a and / or the sound signal AC2 emitted from the sound hole 123a of the housing 12 has a predetermined frequency f th The sharpness of the peak above is Q c In this case, the peak sharpness Q d is the peak sharpness Q c That is, the position of the sound hole 121a (first sound hole) of the housing 12 is shifted to a certain eccentric position, and the position of the sound hole 121a (first sound hole) of the housing 12 is shifted to a certain eccentric position, and the magnitude of the sound signal AC1 (first sound signal) emitted from the sound hole 121a (first sound hole) and / or the sound signal AC2 (second sound signal) emitted from the sound hole 123a (second sound hole) of the housing 12 is shifted to a certain eccentric position, and the magnitude of the sound signal AC2 (second sound signal) is shifted to a certain eccentric position.th Peak sharpness Q d is a predetermined frequency f of the magnitude of the acoustic signal AC1 (first acoustic signal) emitted from the sound hole 121a (first sound hole) of the housing 12 and / or the acoustic signal AC2 (second acoustic signal) emitted from the sound hole 123a (second sound hole) when it is assumed that the sound hole 121a is provided at the center position. th Peak sharpness Q c In other words, the magnitude of the acoustic signal AC1 and / or the acoustic signal AC2 emitted from the housing 12 in which the position of the sound hole 121a is shifted to a certain eccentric position is lower than the predetermined frequency f th The peaks in the above range are determined by the predetermined frequency f of the magnitude of the acoustic signal AC1 and / or the acoustic signal AC2 emitted from the housing 12 when the sound hole 121a is assumed to be located at the center. th The peak is flatter than the peaks above. The position of the sound hole 121a may be shifted to such an eccentric position.

[0035] If the position of one or more sound holes 121a is biased to an eccentric position, the distribution and opening area of ​​the sound holes 123a may be biased accordingly. For example, as shown in Figure 13A or 13B, the position of one or more sound holes 121a provided in area AR1 may be biased to an eccentric position on axis A12 that is offset from axis A1, and as shown in Figures 14A and 14B, the opening area of ​​the sound holes 123a provided in area AR3 may also be biased toward the eccentric position on axis A12. In the example of Figure 14A, the number of sound holes 123a provided along unit arc area C1-3, which is far from the eccentric position on axis A12, is fewer than the number of sound holes 123a provided along unit arc area C1-1, which is closer to that eccentric position. 14B, the opening area of ​​each of the sound holes 123a provided along unit arc region C1-3, which is far from the eccentric position on axis A12, is smaller than the opening area of ​​each of the sound holes 123a provided along unit arc region C1-1, which is closer to the eccentric position. In other words, when circumference C1 is equally divided into multiple unit arc regions, the sum of the opening areas of the sound holes 123a (second sound holes) provided along a first arc region (for example, C1-3), which is one of the unit arc regions, is smaller than the sum of the opening areas of the sound holes 123a provided along a second arc region (for example, C1-1), which is one of the unit arc regions closer to the eccentric position than the first arc region. When the position of the sound holes 121a is biased toward the eccentric position, the distribution of the acoustic signal AC1 emitted to the outside from the sound holes 121a is also biased toward the eccentric position. Here, by biasing the distribution and opening area of ​​the sound holes 123a to the eccentric position, the distribution of the acoustic signal AC2 emitted to the outside from the sound holes 123a can also be biased to the eccentric position, thereby allowing the emitted acoustic signal AC2 to sufficiently cancel out the sound leakage component of the acoustic signal AC1.

[0036] To control the resonant frequency of the housing 12 for other purposes, the sound hole 121a may be positioned eccentrically away from the center (central position) of the region AR1 of the wall 121 of the housing 12. The size of the openings of the sound holes 121a and 123a, the thickness of the wall 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 increased or decreased. In other words, the larger the size of the openings of the sound holes 121a and 123a, the thinner the wall 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 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, acoustic signal AC2, which is an opposite-phase signal of acoustic signal AC1 or an approximation of the opposite-phase signal, is emitted from sound hole 123a, and a portion of acoustic signal AC1 (sound leakage component) emitted from sound hole 121a is canceled out by a portion of the emitted acoustic signal AC2. For this purpose, when the direct wave of acoustic signal AC1 is mainly emitted from sound hole 121a, it is desirable that the direct wave of acoustic signal AC2 is mainly emitted from sound hole 123a. Because reflected waves have a different propagation path than direct waves, if the acoustic signal AC2 emitted from sound hole 123a contains a reflected wave, there is a possibility that the acoustic signal AC2 emitted from sound hole 123a will exhibit a different phase from the opposite-phase signal of acoustic signal AC1 or an approximation of the opposite-phase signal emitted from sound hole 121a, which could reduce the efficiency of canceling out the sound leakage component. That is, it is desirable that the housing 12 has an internal structure that suppresses echoes of the acoustic signal AC2 (second acoustic signal) inside the housing 12, and that the direct wave of the acoustic signal AC2 is mainly emitted from the sound hole 123a (second sound hole). An example of such a configuration will be described below.

[0038] <Example 3-1> An echo suppressing material (e.g., sponge, paper, etc.) that suppresses echoes may be installed in the internal regions (e.g., regions AR2, AR3) of the wall of the housing 12. The wall of the housing 12 itself may be made of the echo suppressing material, or a sheet-like echo suppressing material may be fixed to the wall of the housing 12. Alternatively, the internal regions (e.g., regions AR2, AR3) of the wall of the housing 12 may be made uneven to suppress echoes. Alternatively, a sheet with an uneven surface that has an echo suppressing effect may be fixed to the internal regions of the wall of the housing 12.

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

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

[0041] [Fourth Modification 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 more difficult to cancel out the sound leakage component of the acoustic signal AC1 with the acoustic signal AC2. In some cases, it may be difficult to align the phases of the acoustic signals AC1 and AC2 at high frequencies, and it may even be possible that the sound leakage component of the acoustic signal AC1 is amplified by the acoustic signal AC2. Therefore, it may be better to suppress the high-frequency acoustic signal AC2 from the sound hole 123a. For this reason, a 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 set to a predetermined frequency f2. th The frequency f2 is equal to or less than the predetermined frequency f2 th is greater than the given frequency f2 th Examples of the frequency are 3000Hz, 4000Hz, 5000Hz, 6000Hz, etc. The sound absorption coefficient α of a sound absorbing material is the ratio of the energy of an acoustic signal input to the sound absorbing material to E in The energy of the acoustic signal reflected by the sound absorbing material or the energy of the acoustic signal that passes through the sound absorbing material is E out In this case, α=(E in -E out ) / E in Examples of such sound-absorbing materials include paper such as Japanese paper and Japanese writing paper, nonwoven fabric, silk, and cotton.

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

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

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

[0045] <Experimental Results> The following shows experimental results demonstrating the sound leakage suppression effect of the acoustic signal output device 10 of this modified example. This experiment was conducted using the acoustic signal output device 10 of the first embodiment (no acoustic absorbent) and the acoustic signal output device 10 in which the sound hole 123a is covered with acoustic absorbent material as illustrated in this modified example (with acoustic absorbent). Japanese paper was used as the acoustic absorbent material. In this experiment, as shown in FIG. 5B , the acoustic signal output device 10 was attached to both ears of a dummy head 1100 simulating a human head, and acoustic signals were observed at positions P1 and P2. Position P1 was located near the left ear 1120 of the dummy head 1100 (near the acoustic signal output device 10), and position P2 was located 15 cm outward from position P1.

[0046] Fig. 17 illustrates the frequency characteristics of the acoustic signal observed at position P1 in Fig. 5B, Fig. 18 illustrates the frequency characteristics of the acoustic signal observed at position P2 in Fig. 5B, and Fig. 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 (Hz), and the vertical axis represents sound pressure level (SPL) (dB). The solid line graph illustrates the frequency characteristics when an acoustic signal output device 10 in which the sound hole 123a is covered with sound-absorbing material is used (with acoustic absorbent), and the dashed line graph illustrates the frequency characteristics when the acoustic signal output device 10 of the first embodiment is used (no acoustic absorbent). 19, it can be seen that in the frequency band of 2000 Hz or higher, 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 in which the sound hole 123a is covered with sound-absorbing material than when using an acoustic signal output device 10 without sound-absorbing material. This shows that in the frequency band of 2000 Hz or higher, the use of an acoustic signal output device 10 in which the sound hole 123a is covered with sound-absorbing material generally results in better suppression of sound leakage at position P2.

[0047] [Second embodiment] Next, a second embodiment of the present invention will be described. The second embodiment is a modified example of the first embodiment. The following description will focus on differences from the matters described so far, and the same reference numerals will be used to simplify the description of matters already described.

[0048] In order to improve the sound quality of the acoustic signal output device 10 of the first embodiment or its modified examples, it may be necessary to increase the size of the driver unit 11. However, in the first embodiment or its modified examples, increasing the size of the driver unit 11 also increases the size and weight of the acoustic signal output device 10 itself. However, wearing an acoustic signal output device 10 with a large size and weight near the ear canal increases the strain on the ear and the foreign body sensation. For this reason, the housing with the sound hole and the driver unit 11 may be made separate bodies 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 worn near the ear canal. This is explained in detail below.

[0049] Acoustic signal output device 20 of this embodiment is also a device for listening to sound that is worn without sealing the user's ear canal. As illustrated in Fig. 20, acoustic signal output device 20 of this embodiment has driver unit 11, housing 22 having hollow portions AR21 and AR22 (first and second hollow portions), housing 23 that houses driver unit 11 inside, hollow waveguides 24 and 25 (first and second waveguides) that connect housings 22 and 23, and hollow joining members 26 and 27 that connect waveguides 24 and 25 to housing 22.

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

[0051] <Case 23> As illustrated in FIG. 20, housing 23 is a hollow member with a wall on the outside, and houses driver unit 11 inside. There are no limitations on the shape of housing 23, but it is desirable that the shape of housing 23 be rotationally symmetric (line symmetric) or approximately rotationally symmetric about axis A2 extending along the D3 direction. In this embodiment, for simplicity of explanation, an example is shown in which housing 23 has an approximately cylindrical shape with both end faces. However, this is only an example and does not limit the present invention. For example, housing 23 may be approximately dome-shaped with walls at the ends, or may be approximately hollow and cubic, or may have any other three-dimensional shape. One end 241 of waveguide 24 is attached to wall 231 of housing 23, which is arranged on surface 111 on one side (D3 direction side) of driver unit 11. Waveguide 24 (first waveguide), one end 241 of which is connected to one side (D3 direction side) of driver unit 11 in this manner, guides acoustic signal AC1 emitted from surface 111 of driver unit 11 to one side (D3 direction side) to the outside of housing 23. One end 251 of waveguide 25 is attached to wall portion 232 of housing 23, which is arranged on the side of surface 112 on the other side (D4 direction side) of driver unit 11. Waveguide 25 (second waveguide), one end 251 of which is connected to the other side (D4 direction side) of driver unit 11 in this manner, guides acoustic signal AC2 emitted from surface 112 of driver unit 11 to the other side (D4 direction side) to the outside of housing 23. There are no limitations on the material from which housing 23 is made. Housing 23 may be made of a rigid body such as synthetic resin or metal, or may be made of an elastic body such as rubber.

[0052] <Waveguide 24,25> 20 , the waveguides 24 and 25 are, for example, hollow members configured in a tube 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 them from the other end 242 and 252. However, the waveguides 24 and 25 are not limited to being tubular, and may be any structure that guides an acoustic signal collected at one end 241 and 251 (first position) to the other end 242 and 252 (second position) different from the one end 241 and 251 (first position). There are no limitations on the lengths of the waveguides 24 and 25, but it is preferable that the length of the sound path of the waveguide 24 and the length of the sound path of the waveguide 25 are equal, or that the difference between the lengths of the sound path of the waveguide 24 and the sound path of the waveguide 25 is an integer multiple of the wavelength of the acoustic signals AC1 and AC2. That is, when the length of the sound path of waveguide 24 (first waveguide) is L1, the length of the sound path of waveguide 25 (second waveguide) is L2, where n is an integer, and acoustic signal AC1 (first acoustic signal) and acoustic signal AC2 (second acoustic signal) contain acoustic signals with wavelength λ, it is desirable to satisfy L1 = L2 + nλ. Note that a sound path is a path through which sound passes, and when waveguides 24 and 25 have the same inner diameter, a specific example of the length of the sound path of waveguides 24 and 25 is the length of waveguides 24 and 25. Note that there are no limitations on the material from which waveguides 24 and 25 are made. Waveguides 24 and 25 may be made of a rigid body such as synthetic resin or metal, or may be made of an elastic body such as rubber.

[0053] <Joint member 26> The joining member 26 is a hollow member having an open end 261 located on one side, a wall portion 262 serving as a bottom surface located on the other side of the open end 261, and a wall portion 263 serving as a side surface surrounding the space between the open end 261 and the wall portion 262 about an 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 symmetrical with respect to the axis A1. In this embodiment, for simplicity of explanation, an example is shown in which the wall portion 263 has a cylindrical shape, but the wall portion 263 may have another shape, such as a rectangular column shape. The other end 242 of the waveguide 24 is attached to the wall portion 263, and an acoustic signal AC1 emitted from the other end 242 of the waveguide 24 is introduced into the inside of the joining member 26 (the space between the open end 261 and the wall portion 262). The acoustic signal AC1 introduced into the inside of the joining member 26 is emitted from the open end 261. There are no limitations on the material that makes up the joining member 26. The joining member 26 may be made of a rigid body such as synthetic resin or metal, or may be made of an elastic body such as rubber.

[0054] <Joint member 27> Similarly, the joining member 27 is a hollow member having an open end 271 located on one side, a wall portion 272 serving as a bottom surface located on the other side of the open end 271, and a wall portion 273 serving as a side surface surrounding the space between the open end 271 and the wall portion 272 about an 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 approximately perpendicular to the wall portion 272. Also preferably, the joining member 27 is rotationally symmetrical with respect to the axis A1. In this embodiment, for simplicity of explanation, an example is shown in which the wall portion 273 has a cylindrical shape, but the wall portion 273 may have another shape, such as a rectangular column shape. The other end 252 of the waveguide 25 is attached to the wall portion 273, and an acoustic signal AC2 emitted from the other end 252 of the waveguide 25 is introduced into the inside of the joining member 27 (the space between the open end 271 and the wall portion 272). Acoustic signal AC2 introduced into joining member 27 is emitted from open end 271. There are no limitations on the material that makes up joining member 27. Joining member 27 may be made of a rigid body such as synthetic resin or metal, or may be made of an elastic body such as rubber.

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

[0056] A joining member 26, to which the other end 242 of the waveguide 24 is attached, is fixed to or integrated with the inner wall of the hollow portion AR21, and an open end 261 of the joining member 26 faces the wall 221. For example, the wall 262 of the joining member 26 is fixed to or integrated with the wall 224 inside the hollow portion AR21, and the open end 261 faces the wall 221. In this embodiment, the centers of the wall 262 and the open end 261 of the joining member 26 are located on the axis A1. As a result, the other end 242 of the waveguide 24 is connected to the hollow portion AR21 via the joining member 26, and the acoustic signal AC1 sent to the joining member 26 is emitted from the open end 261 toward the wall 221 (direction D1). That is, for example, the joining member 26 is arranged on the axis A1, 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 toward the direction D1 inside the hollow portion AR21.

[0057] A through hole 222a is provided in the wall portion 222 of the hollow portion AR22. The through hole 222a is preferably located on the axis A1, and more preferably, the center of the through hole 222a is located on the axis A1. The shape of the through hole 222a is not limited, but the opening of the through hole 222a is preferably rotationally symmetrical with respect to the axis A1, and more preferably, the edge of the opening of the through hole 222a is circular. A joining member 27, to which the other end 252 of the waveguide 25 is attached, is fixed or integrated with the outer surface of the wall portion 222 of the housing 22, and an open end 271 of the joining member 27 faces 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 portion 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 portion AR22. For example, the acoustic signal AC2 is emitted from the open end 271 toward the wall portion 224 side (the D1 direction side). That is, for example, the joining member 27 is disposed on the axis A1, the open end 271 of the joining member 27 is open toward the direction D1 (first direction) along the axis A1, and the acoustic signal AC2 introduced from the other end 252 of the waveguide 25 is emitted toward the interior of the hollow portion AR22 in the direction D1.

[0058] The shape of the housing 22 is not limited. For example, it is desirable that the shape of the housing 22 be rotationally symmetric or approximately rotationally symmetric about the axis A1. In this embodiment, for simplicity of explanation, an example is shown in which the exterior shape of the housing 22 is an approximately cylindrical shape having wall portions 221 and 222 at both end faces and wall portion 223 at the side face. Furthermore, in this embodiment, an example is shown in which the wall portions 221, 222, and 224 are perpendicular or approximately perpendicular to the axis A1, and the wall portion 223 is parallel or approximately parallel to the axis A1. However, these are merely examples and do not limit the present invention. For example, the exterior shape of the housing 22 may be an approximately dome shape with wall portions at the end, a hollow approximately cubic shape, or any other three-dimensional shape. Furthermore, there is no limit to the material constituting the housing 22. The housing 22 may be made of a rigid body such as synthetic resin or metal, or an elastic body such as rubber.

[0059] <Sound holes 221a, 223a> A wall 221 of the hollow portion AR21 (first hollow portion) is provided with a sound hole 221a (first sound hole) that guides to the outside the acoustic signal AC1 (first acoustic signal) introduced into the hollow portion AR21 by the waveguide 24 (first waveguide). A wall 223 of the hollow portion AR22 (second hollow portion) is provided with a sound hole 223a (second sound hole) that guides to the outside the acoustic signal AC2 (second acoustic signal) introduced into the hollow portion AR22 by the waveguide 25 (second waveguide). Similar to the sound holes 121a and 123a of the first embodiment, the sound holes 221a and 223a are, for example, through-holes that penetrate the wall 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 they can guide the acoustic signals AC1 and AC2 to the outside, respectively.

[0060] The acoustic signal AC1 emitted from the sound hole 221a reaches the ear canal of the user and is heard by the user. Meanwhile, an acoustic signal AC2, which is an inverse phase signal of the acoustic signal AC1 or an approximate signal of the inverse phase signal, is emitted from the sound hole 223a. A portion of this acoustic signal AC2 cancels out a portion (sound leakage component) of the acoustic signal AC1 emitted from the sound hole 221a. This makes it possible to suppress sound leakage.

[0061] The arrangement of the sound holes 221a and 223a is shown below. Sound hole 221a (first sound hole) in this embodiment is provided in wall 221 of hollow portion AR21 arranged on one side (the D1 direction side, which is the side from which acoustic signal AC1 is emitted) of joining member 26 (FIGS. 20, 21A, 21B, and 22A). Sound hole 223a (second sound hole) in this embodiment is provided in wall 223 that contacts hollow portion AR22. That is, with the center of hollow portion AR22 as the reference point, and the direction between the D1 direction (first direction) and the direction opposite to the D1 direction as the D12 direction (second direction) (FIG. 22A), sound hole 221a (first sound hole) is provided on the D1 direction side (first direction side) of housing 22, and sound hole 223a (second sound hole) is provided on the D12 direction side (second direction side) of housing 22. That is, sound hole 221a opens in direction D1 (first direction) along axis A1, and sound hole 223a opens in direction D12 (second direction). For example, in a case where the outer shape of housing 22 has a first end face which is wall portion 221 arranged on one side (D1 direction side) of joining member 26, a second end face which is wall portion 222 arranged on the other side (D2 direction side) of joining member 26, and a side face which is wall portion 223 that surrounds the space sandwiched between the first end face and the second end face around axis A1 along the emission direction (D1 direction) of acoustic signal AC1 that passes through the first end face and the second end face (FIGS. 21B and 22A), sound hole 221a (first sound hole) is provided in the first end face, and sound hole 223a (second sound hole) is provided in the side face. In addition, in this embodiment, no sound hole is provided on the wall portion 222 side of housing 22. If a sound hole is 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 required to offset the sound leakage component of the acoustic signal AC1, and this excess will be perceived as sound leakage.

[0062] As illustrated in FIG. 21A and other figures, the sound hole 221a of this embodiment is disposed on or near an axis A1 that extends along the emission direction (D1 direction) of the acoustic signal AC1. The axis A1 of this embodiment passes through the center or near the center of the area of ​​the wall portion 221 disposed on one side (D1 direction side) of the joining member 26. For example, the 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 of this embodiment is provided at the center of the area of ​​the wall portion 221 of the housing 22. For simplicity of explanation, this embodiment illustrates an example in which the edge of the open end of the sound hole 221a has a circular shape (the open end is circular). However, this does not limit the present invention. For example, the edge of the open end of the sound hole 221a may have another shape, such as an ellipse, a rectangle, or a triangle. The open end of the sound hole 221a may also have a mesh-like shape. In other words, the open end of the sound hole 221a may be composed of multiple holes. In addition, 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] As in the first embodiment, as illustrated in Figures 21B and 22B, a plurality of sound holes 223a (second sound holes) of this embodiment are provided along a circumference C1 centered on an axis A1 that lies along the emission direction of an acoustic signal AC1 (first acoustic signal). For the sake of simplicity, this embodiment shows an example in which a plurality of sound holes 223a are provided on the circumference C1. However, it is sufficient that a plurality of sound holes 223a are provided along the circumference C1, and it is not necessary that all of the sound holes 223a are positioned strictly on the circumference C1.

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

[0065] As in the first embodiment, it is more preferable that the plurality of sound holes 223a be provided along the circumference C1 with the same shape, size and intervals, although this does not limit the present invention.

[0066] In this embodiment, for the sake of simplicity, an example is shown in which the edge of the open end of sound hole 223a has a rectangular shape, but this does not limit the present invention. For example, the edge of the open end of sound hole 223a may have another shape, such as a circle, an ellipse, or a triangle. The open end of sound hole 223a may also have a mesh-like shape. In other words, the open end of sound hole 223a may be composed of multiple holes. There is also no limitation on the number of sound holes 223a; either a single sound hole 223a or multiple sound holes 223a may be provided in wall 223 of housing 22.

[0067] As in the first embodiment, it is desirable that the ratio S2 / S1 of the sum S2 of the opening areas of the sound holes 223a (second sound holes) to the sum S1 of the opening areas of the sound holes 221a (first sound holes) 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 arranged on one side (the D1 direction side) of the joining member 26, a second end face which is a wall portion 222 arranged on the other side (the D2 direction side) of the joining member 26, and side faces which are wall portions 223 that surround the space sandwiched between the first end face and the second end face around an axis A1 that runs along the emission direction (the D1 direction) of the acoustic signal AC1 that passes through the first end face and the second end face ( FIGS. 21B and 22A ), it is desirable that the ratio S2 / S3 of the sum S2 of the opening areas of the sound holes 223a to the total area S3 of the side faces satisfies 1 / 20≦S2 / S3≦1 / 5.

[0068] <Usage status> 23A and 23B illustrate an example of how the acoustic signal output device 20 is used. In the example of FIG. 23A, one acoustic signal output device 20 is worn in each of the right ear 1010 and left ear (not shown) of a user 1000. Any wearing mechanism is used to wear the acoustic signal output device 20 in the ears. The housings 22 of the acoustic signal output device 20 are disposed on the ear canal 1011 side of the right ear 1010 and left ear, with the D1 direction side facing the ear canal 1011 of the user 1000. The playback device 210 including the housing 23 is disposed on the back side of the pinna of the right ear 1010 and left ear, respectively, and the housings 23 and 22 are connected by the waveguides 24 and 25 as described above. The acoustic signal AC1 introduced from the driver unit 11 in the housing 23 into the hollow portion AR21 of the housing 22 is emitted from the sound hole 221a, and the emitted acoustic signal AC1 is heard by the user 1000. On the other hand, acoustic signal AC2 introduced from driver unit 11 in housing 23 into hollow portion AR22 of housing 22 is emitted from sound hole 223a. Part of this acoustic signal AC2 is an opposite phase signal to acoustic signal AC1 or a signal approximating the opposite phase signal, and cancels out part of acoustic signal AC1 (sound leakage component) emitted from sound hole 221a.

[0069] As in the example of Fig. 23B, playback device 210 including housing 23 may be placed on the head on the front side of right ear 1010 and left ear pinna, and as described above, housing 23 and housing 22 may be connected by waveguides 24 and 25. The rest is the same as the example of Fig. 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 having the same arrangement as the sound holes 123a in Modification 1 of the first embodiment may be provided in the housing 22 (FIGS. 10A to 12C).

[0071] [Modification 2 of the Second Embodiment] In the second embodiment, a configuration has been exemplified in which one sound hole 221a is arranged at the center position of the wall portion 221 of the housing 22. However, similar to the second modification of the first embodiment, a plurality of sound holes 221a may be provided in the area of ​​the wall portion 221 of the housing 22, or the sound hole 221a may be biased to an eccentric position that is shifted from the center of the area of ​​the wall portion 221 of the housing 22. For example, sound holes 221a may be provided in the housing 22 in the same arrangement as the arrangement of the sound holes 221a in the second modification of the first embodiment (FIGS. 13A and 13B).

[0072] Furthermore, as in the second modification of the first embodiment, when the position of one or more sound holes 221a is biased toward an eccentric position, the distribution and opening area of ​​the sound holes 223a may be biased accordingly. That is, when the circumference C1 is equally divided into a plurality of unit arc regions, the sum of the opening areas of the sound holes 223a (second sound holes) provided along a first arc region, which is one of the unit arc regions, may be smaller than the sum of the opening areas of the sound holes 223a provided along a second arc region, which is one of the unit arc regions closer to the eccentric position than the first arc region. For example, sound holes 223a arranged in the same configuration as the sound holes 123a in the second modification of the first embodiment may be provided in the housing 22 (FIGS. 14A and 14B). Alternatively, the resonant frequency of the housing 22 may be controlled by controlling the size of the openings of the sound holes 221a and 223a, the thickness of the wall of the housing 22, and at least a portion of the internal volume of the housing 22.

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

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

[0075] 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 (FIGS. 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 (D1 direction side) of the housing 22 (e.g., the sound hole 221a side) and the open end 271 of the joining member 27 faces the wall portion 222 side (D2 direction side) of the housing 22. Even with this 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] A plurality of acoustic signal output devices 10, as described in the first embodiment or its modified examples, may be provided and independently controlled. This allows the sound pressure level of an acoustic signal AC1 emitted from one acoustic signal output device 10 and the sound pressure level of an acoustic signal AC2 emitted from another acoustic signal output device 10 to be independently controlled. For example, one acoustic signal output device 10 and another acoustic signal output device 10 may be driven in opposite phases or substantially opposite phases, allowing the levels (power) at each frequency to be independently controlled. As a result, as illustrated in the first embodiment, the sound leakage components of the acoustic signals AC1 from each acoustic signal output device 10 are canceled out by a portion of the acoustic signal AC2, and portions of the acoustic signals AC1 and AC2 output from different acoustic signal output devices 10 can be canceled out. As a result, the sound leakage components can be more appropriately canceled out. For simplicity's sake, this embodiment illustrates an example in which two acoustic signal output devices 10 are provided for one ear and independently controlled. However, this does not limit the present invention, and three or more acoustic signal output devices 10 may be provided for one ear and controlled independently. The same reference numerals will be used to refer to matters already described, and explanations will be omitted. However, subnumbers will be used to distinguish between multiple components with the same configuration. 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 configuration of acoustic signal output devices 10-1 and 10-2 is the same as that of acoustic signal output device 10.

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

[0078] <Audio 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 exemplified 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. Based on an 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) toward the D1-1 direction (one side), and emits an acoustic signal AC2-1 (second acoustic signal) that is an inverse phase signal of the acoustic signal AC1-1 (first acoustic signal) or a signal approximating the inverse phase signal toward the D2-1 direction (other side). A wall portion 121-1 of the housing 12-1 is provided with one or more sound holes 121a-1 (first sound holes) that guide the acoustic signal AC1-1 (first acoustic signal) emitted from the driver unit 11-1 to the outside. Wall 123-1 of housing 12-1 is provided with one or more sound holes 123a-1 (second sound holes) that guide acoustic signal AC2-1 (second acoustic signal) emitted from driver unit 11-1 to the outside. The detailed configuration of acoustic signal output device 10-1 is the same as that of acoustic signal output device 10 described in the first embodiment. For example, a plurality of sound holes 123a-1 (second sound holes) are provided along a circumference C1-1 (first circumference) centered on axis A1-1 (first axis) that is parallel or approximately parallel to a straight line extending in direction D1-1 (first direction) (FIG. 29). For example, when the circumference C1-1 (first circumference) is equally divided into a plurality of first unit arc regions, the sum of the opening areas of the sound holes 123a-1 (second sound holes) provided along any one of the first unit arc regions is the same as or approximately the same as the sum of the opening areas of the sound holes 123a-1 (second sound holes) provided along any one of the second unit arc regions excluding the first arc region.

[0079] <Audio signal output device 10-2> The configuration of the acoustic signal output device 10-2 is also the same as that of the acoustic signal output device 10 exemplified 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 portion) that houses the driver unit 11-2. Based on an 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) toward the D1-2 direction (one side), and emits an acoustic signal AC2-2 (third acoustic signal) that is an inverse phase signal of or an approximate signal to the inverse phase signal of the acoustic signal AC1-2 toward the D2-2 direction (the other side). The phase of the acoustic signal AC1-2 (fourth acoustic signal) is the same as or approximate to the phase of the acoustic signal AC2-1 (second acoustic signal). The phase of acoustic signal AC2-2 (third acoustic signal) is the same as or similar to the phase of acoustic signal AC1-1 (first acoustic signal). Driver unit 11-2 may be of the same design as driver unit 11-1, or may be of a different design from driver unit 11-1. For example, driver unit 11-2 may be smaller than driver unit 11-1, or the performance of driver unit 11-2 may be inferior to driver unit 11-1. Wall 123-2 of housing 12-2 is provided with one or more sound holes 123a-2 (third sound holes) that guide acoustic signal AC2-2 (third acoustic signal) emitted from driver unit 11-2 to the outside. Wall 121-2 of housing 12-2 is provided with one or more sound holes 121a-2 (fourth sound holes) that guide acoustic signal AC1-2 (fourth acoustic signal) emitted from driver unit 11-2 to the outside. The detailed configuration of the acoustic signal output device 10-2 is the same as that of the acoustic signal output device 10 described in the first embodiment. For example, a plurality of 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 approximately parallel to a straight line extending in a direction D1-2 (fourth direction) (FIG. 29).For example, when the circumference C1-2 (fourth circumference) is equally divided into a plurality of fourth unit arc regions, the sum of the opening areas of the sound holes 123a-2 (third sound holes) provided along a third arc region that 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 sound holes 123a-2 (third sound holes) provided along a fourth arc region that is one of the fourth unit arc regions excluding the third arc region.

[0080] <Connection part 32> As illustrated in FIGS. 27, 28, and 29, the connecting portion 32 secures 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 FIG. 28, the outside of the wall 123-1 of the housing 12-1 of the acoustic signal output device 10-1 and the outside of the wall 123-2 of the housing 12-2 of the acoustic signal output device 10-2 are joined together. The sound hole 121a-1 (first sound hole) opens in a direction D1-1 (first direction) along the axis A1-1. Note that the direction D1-1 is a direction along the axis A1-1. The sound hole 123a-1 (second sound hole) opens in a direction D12-1 (second direction) between the direction D1-1 (first direction) and the opposite direction of the direction D1-1 (first direction). The sound hole 121a-2 (fourth sound hole) opens facing a direction D1-2 (fourth direction) that is the same as or similar to the direction D1-1 (first direction). The direction D1-2 is along the axis A1-2. The sound hole 123a-2 (third sound hole) opens facing a direction D12-2 (third direction) between the direction D1-2 (fourth direction) and the opposite direction of the direction D1-2 (fourth direction). However, this arrangement is merely an example and does not limit the present invention.

[0081] 27, 28, and 29, it is preferable that sound hole 121a-1 (first sound hole) and sound hole 121a-2 (fourth sound hole) are plane-symmetric or approximately plane-symmetric with respect to reference plane P31 that includes a straight line parallel or approximately parallel to a straight line (axis A1-1) extending in direction D1-1 (first direction). Similarly, it is preferable that sound hole 123a-1 (second sound hole) and sound hole 123a-2 (third sound hole) are plane-symmetric or approximately plane-symmetric with respect to reference plane P31. More preferably, housing 12-1 (first housing portion) and housing 12-2 (second housing portion) are plane-symmetric or approximately plane-symmetric with respect to reference plane P31.

[0082] <Circuit part 31> Circuit section 31 is a circuit that uses as input an input signal that is an electrical signal representing an acoustic signal, 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 signal I and output signal II are electrical signals that represent acoustic signals, and output signal II is an opposite-phase signal of output signal I or a signal approximating said opposite-phase signal. An example of the configuration of circuit section 31 is shown below.

[0083] <Configuration example 1 of circuit unit 31> The circuit section 31 illustrated in FIG. 30A has a phase inversion section 311, which is a phase inversion circuit. An input signal input to the circuit section 31 is output as is as output signal I and supplied to driver unit 11-1. Furthermore, the input signal input to the circuit section 31 is also input to the phase inversion section 311. The phase inversion section 311 outputs an inverse phase signal of the input signal or a signal approximating the inverse phase signal as output signal II. The output signal II is supplied to driver unit 11-2.

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

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

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

[0087] Example 31-1: For example, the magnitude (level) of the high frequency side of the acoustic signals AC2-2 and AC1-2 may be suppressed more than the magnitude (level) of the high frequency side of the acoustic signals AC1-1 and AC2-1. That is, the frequency f 31 The magnitude of the components above (first frequency) is equal to or greater than the frequency f of the acoustic signals AC1-1 and AC2-1 (first acoustic signal and second acoustic signal) emitted from driver unit 11-1 (first driver unit). 31 For example, when driver unit 11-2 receives a frequency f 31 The acoustic signals AC2-2 and AC1-2 may be output with the above frequency bands suppressed. 31 Examples of frequencies include 3000Hz, 4000Hz, 5000Hz, and 6000Hz.

[0088] Example 31-2: For example, the magnitude of the low-frequency side of the acoustic signals AC2-2 and AC1-2 may be suppressed more than the magnitude of the low-frequency side of the acoustic signals AC1-1 and AC2-1. That is, the frequency f 32 The magnitude of the components below (second frequency) is equal to or less than the frequency f of the acoustic signals AC1-1 and AC2-1 (first acoustic signal and second acoustic signal) emitted from driver unit 11-1 (first driver unit). 32 For example, when driver unit 11-2 is 32 The acoustic signals AC2-2 and AC1-2 may be output with the following frequency bands suppressed: 32 Examples of frequencies are 1000Hz, 2000Hz, and 3000Hz.

[0089] Example 31-3: For example, the magnitude of the high-frequency side of the acoustic signals AC2-2 and AC1-2 may be suppressed more than the magnitude of the high-frequency side of the acoustic signals AC2-1 and AC1-1, and the magnitude of the low-frequency side of the acoustic signals AC2-2 and AC1-2 may be suppressed more than the magnitude of the low-frequency side of the acoustic signals AC2-1 and AC1-1. 32 The following frequency bands and frequency f 31 The above frequency bands are suppressed in the acoustic signal AC2-2 and the acoustic signal AC1-2 (for example, the frequency f 32 and frequency f 31 Alternatively, an acoustic signal AC2-2 and an acoustic signal AC1-2 may be output, which include only signals in the frequency band between the frequencies AC1-1 and AC2-2.

[0090] A third example of the configuration of the circuit unit 31 that achieves this will be illustrated below. As illustrated in FIG. 30C, the circuit section 31 of this example has a level correction section 312, a phase control section 313, a delay correction section 314, and a band-pass filter section 315. An input signal input to the circuit section 31 is input to the band-pass filter section 315 and the delay correction section 314. The band-pass filter section 315 obtains and outputs a band-limited signal by limiting (narrowing) the band of the input signal. In the case of the above-mentioned example 31-1, the high-frequency side of the input signal (for example, frequency f 31 In the case of the above example 31-2, the low-frequency side of the input signal (for example, the frequency f 32 In the case of the above example 31-3, the high-frequency side of the input signal (for example, the frequency f 31 above frequency band) and the lower frequency side (for example, frequency f 32 The signal with the following frequency bands suppressed is output as a band-limited signal.

[0091] The band-limited signal is input to the level correction unit 312. The level correction unit 312 adjusts the level of each band of the band-limited signal and outputs the band-level-adjusted signal obtained thereby. 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 approximation signal of the inverse phase signal, and outputs this as the output signal II. The output signal II is supplied to the driver unit 11-2. Furthermore, the delay correction unit 314 outputs the output signal I obtained by adjusting the delay amount of the input signal.

[0092] <Usage status> FIG. 31 illustrates an example of how the acoustic signal output device 30 is used. One acoustic signal output device 30 is worn on each of the right ear 1010 and left ear (not shown) of a user 1000 in FIG. 31. The D1 direction sides of the acoustic signal output devices 10-1 of the acoustic signal output devices 30 face the ear canal 1011 of the user 1000. The acoustic signal output device 10-2 is positioned offset from the ear canal 1011. For example, when the acoustic signal output device 30 is worn on the ears, the sound hole 121a-1 (first sound hole) faces the ear canal 1011, and the sound holes 123a-1 (second sound hole), 123a-2 (third sound hole), and 121a-2 (fourth sound hole) face in directions other than the ear canal 1011. Any wearing mechanism is used to wear the acoustic signal output device 30 on the ears. 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 the 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 the sound hole 123a-2 (third sound hole) cancels out a portion of the acoustic signal AC2-1 (second acoustic signal) emitted from the sound hole 123a-1 (second sound hole). Furthermore, a portion of the acoustic signal AC1-2 (fourth acoustic signal) emitted from the sound hole 121a-2 (fourth 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). That is, in this embodiment, an acoustic signal AC1-1 (first acoustic signal) is emitted from the sound hole 121a-1 (first sound hole), an acoustic signal AC2-1 (second acoustic signal) is emitted from the sound hole 123a-1 (second sound hole), an acoustic signal AC2-2 (third acoustic signal) is emitted from the sound hole 123a-2 (third sound hole), and an acoustic signal AC1-2 (fourth acoustic signal) is emitted from the sound hole 121a-2 (fourth sound hole). In this case, the attenuation rate η of the acoustic signal AC1-1 (first acoustic signal) at position P2 (second position) relative to position P1 (first position) is11 is the attenuation rate η of the acoustic signal due to air propagation at position P2 (second position) relative to position P1 (first position). 21 A predetermined value η smaller than th Alternatively, in this case, the attenuation amount η of the acoustic signal AC1-1 (first acoustic signal) at the position P2 (second position) relative to the position P1 (first position) is 12 is the attenuation of the acoustic signal due to air propagation at position P2 (second position) relative to position P1 (first position), η 22 a predetermined value ω greater than th The above is the case. Note that position P1 (first point) in this embodiment is a predetermined point reached by acoustic signal AC1-1 (first acoustic signal) emitted from sound hole 121a-1 (first sound hole). On the other hand, position P2 (second point) in this embodiment is a predetermined point that is farther away from acoustic signal output device 30 than position P1 (first point). As a result, sound leakage components from acoustic signal output device 30 are cancelled out. In particular, in this embodiment, the relative level of driver unit 11-2 with respect to driver unit 11-1 can be controlled, and therefore sound leakage can be further reduced compared to when one driver unit 11 is used as in the first embodiment.

[0093] Furthermore, as explained in the configuration example 3 of the circuit unit 31, when a user listens to 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 smaller 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 the acoustic signals AC2-2 and AC1-2 (e.g., the high-frequency side where sound leakage suppression by cancellation is difficult) is suppressed more than the magnitude of the high-frequency side of the acoustic signals AC2-1 and AC1-1, sound leakage can be prevented from being promoted in the high-frequency side. Furthermore, as in Example 31-2, even if the magnitude of the low-frequency side of the acoustic signals AC2-2 and AC1-2 is suppressed more than the magnitude of the low-frequency side of the acoustic signals AC2-1 and AC1-1, the impact of sound leakage is small in applications where the level of low-frequency sounds is low, such as earphones. Furthermore, even if driver unit 11-2 is smaller than driver unit 11-1 or has lower performance, a sufficient sound leakage suppression effect can be expected.

[0094] [Modification 1 of the third embodiment] The acoustic signal output devices 10-1 and 10-2 may be the acoustic signal output device 10 described in the modified example of the first embodiment. For example, as illustrated in Fig. 32A, the position of the sound hole 121a-1 (first sound hole) may be offset to a first eccentric position (a position on an axis A12-1 that is offset from the axis A1-1 and is parallel to the axis A1-1) offset from an axis A1-1 (first central axis) that passes through the central region of the housing 12-1 (first housing part) and extends in a direction D1-1 (first direction). 32B, when the circumference C1-1 (first circumference) is equally divided into a plurality of first unit arc regions, the sum of the opening areas of the sound holes 123a-1 (second sound holes) provided along one of the first unit arc regions may be smaller than the sum of the opening areas of the sound holes 123a-1 (second sound holes) provided along a second arc region that is one of the first unit arc regions closer to the first eccentric position than the first arc region. Similarly, for example, the position of the sound hole 121a-2 (fourth sound hole) may be offset to a fourth eccentric position (a position on axis A12-2 that is offset from axis A1-2 and is parallel to axis A1-2) offset from axis A1-2 (second central axis) that passes through the central region of the housing 12-2 (second housing part) and extends in direction D1-2 (fourth direction). 32B, when the circumference C1-2 (fourth circumference) is equally divided into a plurality of second unit arc regions, the sum of the opening areas of the sound holes 121a-2 (fourth sound holes) provided along a third arc region that is one of the second unit arc regions may be smaller than the sum of the opening areas of the fourth sound holes provided along a fourth arc region that 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 sound holes 121a-1 (first sound hole) and 121a-2 (fourth sound hole) be plane-symmetric or approximately plane-symmetric with respect to a reference plane P31 that includes a straight line that is parallel or approximately parallel to a straight line (axis A1-1) that extends in direction D1-1 (first direction). Similarly, it is desirable that sound hole 123a-1 (second sound hole) and sound hole 123a-2 (third sound hole) are plane-symmetric or approximately plane-symmetric with respect to reference plane P31. More preferably, it is desirable that housing 12-1 (first housing portion) and housing 12-2 (second housing portion) are plane-symmetric or approximately plane-symmetric with respect to reference plane P31.Furthermore, the sound absorbing material described in the modified example 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) of the acoustic signal output device 10-1 and the housing 12-2 (second housing) of the acoustic signal output device 10-2 may be integrated. For example, as illustrated in FIG. 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 an integrated housing 12", and an area AR31 in which the driver unit 11-1 is housed and an area AR32 in which the driver unit 11-2 is housed may be separated by a wall 351 provided inside the housing 12", separating the area AR31 from the area AR32. If areas AR31 and AR32 are separated by wall 351, it is possible to prevent part of acoustic signal AC1-1 and part of acoustic signal AC1-2 from canceling out each other inside housing 12". As such, it is desirable that areas AR31 and AR32 are separated by wall 351. However, areas AR31 and AR32 do not have to be separated by wall 351. In other words, parts of acoustic signals AC1-1 and AC2-1 emitted from driver unit 11-1 may not be emitted from any of sound holes 121a-1, 123a-1, 121a-2, 123a-2, but may be canceled out inside housing 12". Even in this case, the components of acoustic signals AC1-1, AC2-1, AC1-2, AC2-2 that are not canceled out inside housing 12" are emitted to the outside from one of sound holes 121a-1, 123a-1, 121a-2, 123a-2. For example, the components of acoustic signals AC1-1, AC2-1 emitted from driver unit 11-1 that are not canceled out inside housing 12" are emitted to the outside from one of sound holes 121a-1, 123a-1, 121a-2, 123a-2. It goes without saying that these are canceled out by some of the components of other acoustic signals that are emitted from either driver unit 11-1, 11-2 and emitted to the outside from one of sound holes 121a-1, 123a-1, 121a-2, 123a-2. Therefore, even in such a case, the sound leakage suppression effect can be obtained.Furthermore, even when housings 12-1 and 12-2 are integrated as housing 12", it is desirable that sound hole 121a-1 (first sound hole) and sound hole 121a-2 (fourth sound hole) be plane-symmetric or approximately plane-symmetric with respect to reference plane P31. Similarly, it is desirable that sound hole 123a-1 (second sound hole) and sound hole 123a-2 (third sound hole) be plane-symmetric or approximately plane-symmetric with respect to reference plane P31. It is more desirable that housing 12-1 (first housing portion) and housing 12-2 (second housing portion) be plane-symmetric or approximately plane-symmetric with respect to reference plane P31. Furthermore, the sound-absorbing material described in the modification of the first embodiment may be provided inside housing 12" or in any of sound holes 121a-1, 121a-2, 123a-1, and 123a-2. The rest is the same as the third embodiment or its modification 1.

[0096] [Modification 3 of the third embodiment] Acoustic signal output devices 20-1 and 2 having the same configuration as acoustic signal output device 20 of the second embodiment may be used instead of acoustic signal output devices 10-1 and 2 of the third embodiment. For example, as illustrated in Fig. 33B, housings 22-1 and 22-2 of acoustic signal output devices 20-1 and 20-2 may be joined by coupling portion 32, and as described in the second embodiment, housings 22-1 and 23-1 may be connected by waveguides 24-1 and 25-1, and housings 22-2 and 23-2 may be connected by waveguides 24-2 and 25-2. Circuit section 31 supplies output signal I to driver unit 11-1 housed in housing 23-1, and supplies output signal II to driver unit 11-2 housed in housing 23-2. As explained in the second embodiment, 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 acoustic signal AC2-1 is emitted from sound hole 223a-1. Similarly, 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 acoustic signal AC2-2 is emitted from sound hole 223a-2. Other details are the same as those of the third embodiment or its modified examples 1 and 2, except that housings 12-1 and 12-2, sound holes 121a-1, 121a-2, 123a-1 and 123a-2, and wall portions 121-1, 121-2, 122-1, 122-2, 123-1 and 123-2 are replaced with housings 22-1 and 22-2, sound holes 221a-1, 221a-2, 223a-1 and 223a-2, and wall portions 221-1, 221-2, 222-1, 222-2, 223-1 and 223-2. Alternatively, housing 23-1 may be connected to housing 22-1 by waveguides 24-1 and 25-1, and may be connected to housing 23-1 by waveguides 24-2 and 25-2. In this case, circuit section 31 supplies output signal I to driver unit 11-1 housed in housing 23-1. 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 acoustic signal AC2-1 is emitted from sound hole 223a-1. Similarly, 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 acoustic signal AC2-2 is emitted from sound hole 223a-2.Furthermore, the housing 23-1 may be connected to κ housings 22-κ via waveguides 24-κ and 25-κ, where κ=1, . . . , κ. max and κ max is an integer of 2 or greater. In this case, circuit section 31 supplies output signal I to driver unit 11-1 housed in housing 23-1. Acoustic signal AC1-κ sent from housing 23-1 to housing 22-κ via waveguides 24-κ and 25-κ is emitted from sound hole 221a-κ, and 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 circuit section 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 connected to another housing 22-γ via waveguides 24-γ and 25-γ. However, γ=κ max +1,…,γ max and γ max is κ maxis an integer greater than . In this case, output signal II output from circuit section 31 is further supplied to driver unit 11-2 housed in housing 22-2, and acoustic signal AC1-γ sent from housing 23-2 to housing 22-γ via waveguides 24-γ and 25-γ is emitted from sound hole 221a-γ, and acoustic signal AC2-γ is emitted from sound hole 223a-γ. In other words, acoustic signal AC1-1 (first acoustic signal) emitted from one of the single or multiple driver units should be emitted to the outside from sound hole 221a-1 (first sound hole). Also, acoustic signal AC2-1 (second acoustic signal) emitted from one of the single or multiple driver units should be emitted to the outside from sound hole 123a-1 (second sound hole). Furthermore, it is sufficient that acoustic signal AC2-2 (third acoustic signal) emitted from any one of the single or multiple driver units is emitted from sound hole 123a-2 (third sound hole). Furthermore, it is sufficient that acoustic signal AC1-2 (fourth acoustic signal) emitted from any one of the single or multiple driver units is emitted to the outside from sound hole 221a-2 (fourth sound hole). In other words, acoustic signal AC1-1 (first acoustic signal) and 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, acoustic signal AC2-1 (second acoustic signal) and 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 ear canals of a user emits monaural acoustic signals with mutually inverted phases toward the left and right ears. From such an acoustic signal output device, a portion of the monaural acoustic signal is emitted not only toward the ear canals of the user, but also toward the outside of the user. However, because the emitted monaural acoustic signals have mutually inverted phases, the monaural acoustic signals propagating 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 has an acoustic signal output unit 40-1 (first acoustic signal output unit) worn on the right ear (one ear) 1010 of the user 1000, an acoustic signal output unit 40-2 (second acoustic signal output unit) worn on the left ear (the other ear) 1020, and a circuit unit 41.

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

[0100] <Audio signal output units 40-1, 40-2> The acoustic signal output units 40-1 and 40-2 are devices for listening to sound that are worn on both ears without sealing the user's ear canals. An output signal I is input to the acoustic signal output unit 40-1, which converts the output signal I into a monaural acoustic signal MAC1 (a phase identical or substantially identical to that of the monaural acoustic signal MAC1 is represented by "+") and emits it toward the ear canal of the right ear 1010. An output signal II is input to the acoustic signal output unit 40-2, which converts the output signal II into a monaural acoustic signal MAC2 (a phase identical or substantially identical to that of the monaural acoustic signal MAC2 is represented by "-") and emits it toward the ear canal of the left ear 1020. The monaural acoustic signal MAC2 is an inverted phase signal of the monaural acoustic signal MAC1 or an approximate signal of the inverted 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 from each other, there is almost no problem with listening. Although portions of the emitted monaural acoustic signal MAC1 and the emitted monaural acoustic signal MAC2 are also emitted outside both ears, because the monaural acoustic signal MAC1 and the monaural acoustic signal MAC2 are in opposite or nearly opposite phases, they cancel each other out. That is, the portion of the emitted monaural acoustic signal MAC1 (first monaural acoustic signal) and the portion of the emitted monaural acoustic signal MAC2 (second monaural acoustic signal) interfere with each other and cancel each other outward (outward from the user 1000, i.e., the side opposite the right ear 1010) of the acoustic signal output unit 40-1 (first acoustic signal output unit) worn on the right ear 1010 (one ear) and / or outward (outward from the user 1000, i.e., the side opposite the left ear 1020) of the acoustic signal output unit 40-2 (second acoustic signal output unit) worn on the left ear 1020 (the other ear). That is, as described above, the monaural acoustic signal MAC1 (first monaural acoustic signal) is output from the acoustic signal output unit 40-1 (first acoustic signal output unit), and the monaural acoustic signal MAC2 (second monaural acoustic signal) is output from the acoustic signal output unit 40-2 (second acoustic signal output unit). In this case, the attenuation rate η of the monaural acoustic signal MAC1 (first monaural acoustic signal) at the position P2 (second position) relative to the position P1 (first position) is 11 is the attenuation rate η of the acoustic signal due to air propagation at position P2 (second position) relative to position P1 (first position).21 A predetermined value η smaller than th Alternatively, in this case, the attenuation amount η of the first monaural acoustic signal at the position P2 (second position) relative to the position P1 (first position) is 12 is the attenuation of the acoustic signal due to air propagation at position P2 (second position) relative to position P1 (first position), η 22 a predetermined value ω greater than th The above is the case. However, position P1 (first point) in this embodiment is a predetermined position to which monaural acoustic signal MAC1 (first monaural acoustic signal) arrives. Furthermore, position P2 (second point) in this embodiment is a position farther from acoustic signal output unit 40-1 (first acoustic signal output unit) than position P1 (first point). As a result, sound leakage is suppressed.

[0101] [Modification 1 of the Fourth Embodiment] The acoustic signal output units 40-1 and 40-2 may be replaced by the acoustic signal output device 10 of the first embodiment or its modified example, or the acoustic signal output device 20 of the second embodiment or its modified example.

[0102] As illustrated in FIG. 34B, the acoustic signal output device 4′ of this modified example has an acoustic signal output device 10-1 (first acoustic signal output unit) worn on the right ear (one ear) 1010 of the user 1000, an acoustic signal output device 10-2 (second acoustic signal output unit) worn on 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) worn on the right ear (one ear) 1010 of the user 1000, an acoustic signal output device 20-2 (second acoustic signal output unit) worn on 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 a D1-1 direction (one side) and emits a monaural acoustic signal MAC2-1 (second acoustic signal) that is an 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 of the D1-1 direction; The device includes a housing 12-1 or 22-1 (first housing) having one or more sound holes 121a-1 or 221a-1 (first sound hole) provided in a wall portion thereof for guiding to the outside a monaural acoustic signal MAC1-1 (first acoustic signal) emitted from driver unit 11-1, and one or more sound holes 123a-1 or 223a-1 (second sound hole) for guiding to the outside a monaural acoustic signal MAC2-1 (second acoustic signal) emitted from driver unit 11-1.

[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) that is the same as or similar to the monaural acoustic signal MAC2-1 (second acoustic signal) in the D1-2 direction (one side), and emits a monaural acoustic signal MAC2-2 (third acoustic signal) that 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. and housings 12-2, 22-2 (second housings) having one or more sound holes 123a-2 or 223a-2 (third sound hole) for guiding to the outside a monaural acoustic signal MAC2-2 (third acoustic signal) emitted from driver unit 11-2, and one or more sound holes 121a-2 or 221a-2 (fourth sound hole) for guiding to the outside a monaural acoustic signal MAC1-2 (fourth acoustic signal) emitted from driver unit 11-2.

[0105] In this modification, the acoustic signal AC1-1 (first acoustic signal) is the monaural acoustic signal MAC1-1 (first mono 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 mono acoustic signal), and the acoustic signal AC2-2 is the monaural acoustic signal MAC2-2. The other detailed configurations of the acoustic signal output devices 10-1 and 10-2 are the same as those of the acoustic signal output device 10 of the first embodiment or its modification. Furthermore, 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 of the second embodiment or its modification.

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

[0107] A monaural acoustic signal MAC1-1 (first monaural acoustic signal) is emitted from sound hole 121a-1 or 221a-1 of acoustic signal output device 10-1 or 20-1 (first acoustic signal output unit) toward the ear canal of right ear 1010. A monaural acoustic signal MAC1-2 (second monaural acoustic signal) is emitted from sound hole 121a-2 or 221a-2 of acoustic signal output device 10-2 or 20-2 (second acoustic signal output unit) toward the ear canal of left ear 1020. Here, monaural acoustic signal MAC1-2 is an inverted phase signal of monaural acoustic signal MAC1-1 or an approximation signal of the inverted phase signal of monaural acoustic signal MAC1-1. However, even if the phases of the acoustic signals perceived by the left and right ears are inverted from each other, there is almost no problem with listening. Although portions of the emitted monaural acoustic signal MAC1-1 and the emitted monaural acoustic signal MAC1-2 are also emitted outside both ears, they cancel each other out because the monaural acoustic signal MAC1-1 and the monaural acoustic signal MAC1-2 are in opposite or nearly opposite phases. That is, the portion of the emitted monaural acoustic signal MAC1-1 (first monaural acoustic signal) and the portion of the emitted monaural acoustic signal MAC1-2 (second monaural acoustic signal) interfere with each other and cancel each other outward (outward from the user 1000, i.e., opposite the right ear 1010) of the acoustic signal output device 10-1 or 20-1 (first acoustic signal output unit) worn on the right ear 1010 (one ear) and / or outward (outward from the user 1000, i.e., opposite the left ear 1020) of the acoustic signal output device 10-2 or 20-2 (second acoustic signal output unit) worn on the left ear 1020 (the other ear). Furthermore, a monaural acoustic signal MAC2-1 is emitted from the sound hole 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 hole 121a-1 or 221a-1. Furthermore, a monaural acoustic signal MAC2-2 is emitted from the sound hole 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 hole 121a-2 or 221a-2.As a result, sound leakage is suppressed.

[0108] [Modification 2 of the Fourth Embodiment] The output signals I and II in the fourth embodiment or the first modification of the fourth embodiment may be reversed. That is, the input signal input to the circuit unit 41 may be input to the phase inversion unit 413 and the signal output unit 412, the phase inversion unit 413 may output the output signal II (second output signal) which is an inverse phase signal of the input signal or an approximation 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 may output the input signal as is as the 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, a wearing method of an ear-mounted acoustic signal output device will be illustrated. As mentioned above, conventional wearing methods can cause problems such as a heavy burden on the ear and difficulty in stable wearing. In this embodiment, a new wearing method of an acoustic signal output device that solves these problems will be illustrated.

[0110] <Wearing method 1> 35A to 36D illustrate wearing method 1. As illustrated in Fig. 35A to 35C, an acoustic signal output device 2100 of wearing method 1 includes a housing 2112 that emits an acoustic signal, a wearing unit 2121 (first wearing unit) that holds the housing 2112 and is configured to be worn on an upper portion 1022 (first auricle portion) of the auricle 1020, which is a part of the auricle 1020, and a wearing unit 2122 (second wearing unit) that holds the housing 2112 and is configured to be worn on an intermediate portion 1023 (second auricle portion) that is a part of the auricle 1020 different from the upper portion 1022 (first auricle portion). The intermediate portion 1023 is an intermediate portion between the upper portion 1022 (helix side) and the lower portion 1024 (earlobe side) of the auricle 1020. Furthermore, in this embodiment, an example is shown in which the auricle 1020 is a human auricle, but the auricle 1020 may 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'', 22 exemplified in the first to fourth embodiments and their modified examples, or may be the housing of a conventional acoustic signal output device that emits an acoustic signal, such as an earphone. When the acoustic signal output device 2100 is worn, the housing 2112 is positioned so that the sound hole 2112a faces the ear canal 1021 and so that the ear canal 1021 is not blocked.

[0112] The wearing portion 2121 (first wearing portion) in this example has a fixing portion 2121a (first fixing portion) that grips the helix 1022a (end portion) of the upper portion 1022 (first pinna 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 region of the outer wall portion of the fixing portion 2121a, and the other end of the support portion 2121b holds a specific region H1 (first holding region) of the outer wall portion of the housing 2112. One end of the support portion 2121b may be fixed to a specific region of the wall portion of the fixing portion 2121a, or may be integrated with the wall portion of the fixing portion 2121a at the specific region. Similarly, the other end of the support part 2121b may be fixed to a specific region H1 of the outer wall of the housing 2112, or may be integrated with the outer wall of the housing 2112 at the specific region H1. In this way, the support part 2121b holds the housing 2112 from the outer side (first outer side) of the specific region H1 of the wall of the housing 2112. In this example, when the fixing part 2121a is attached to the helix 1022a, the outer side (first outer side) of the region H1 becomes the upper portion 1022 side of the auricle 1020. Here, the fixing part 2121a (first fixing part) is configured to grip the helix 1022a of the upper portion 1022 (first auricle part) of the auricle 1020 from the upper side of the auricle 1020. The housing 2112 is configured to be suspended by the mounting unit 2121 (first mounting unit) including the fixing unit 2121a (first fixing unit) that grips the helix 1022a. That is, the fixing unit 2121a grips the helix 1022a from above the auricle 1020, and the housing 2112 is suspended by one end of the support unit 2121b, which holds the fixing unit 2121a at the other end. A reaction force against the weight of the suspended housing 2112 is supported by the inner wall surface of the fixing unit 2121a. For example, this reaction force is supported by the inner wall surface of the fixing unit 2121a, which is disposed perpendicular or approximately perpendicular to the direction of the reaction force. With this configuration, the weight of the housing 2112 can be supported even if the gripping force of the fixing unit 2121a is small. The smaller the gripping force of the fixing unit 2121a, the smaller the burden on the auricle 1020, and therefore the burden on the ear can be reduced. The fixed portion 2121a may have any specific shape.An example of the fixing portion 2121a is a member having a hollow C- or U-shaped cross section and configured to hold the helix 1022a with the helix 1022a in contact with the inner wall surface 2121aa (see, for example, FIGS. 36A to 36D). For example, the fixing portion 2121a may be shaped like an ear cuff.

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

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

[0115] <Wearing method 2> 37A to 37C illustrate wearing method 2. As illustrated in Fig. 37A to 37C, the acoustic signal output device 2100' of wearing method 2 is obtained by adding to the acoustic signal output device 2100 of wearing method 1 a wearing unit 2123 (second wearing unit) configured to be worn on a lower part 1024 (second auricle part) that is a part of the auricle 1020 different from the upper part 1022 (first auricle part) and the middle part 1023 (second auricle part) of the auricle 1020.

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

[0117] <Wearing method 3> The acoustic signal output device 2100' of the wearing method 2 may have a configuration in which the wearing unit 2122 is omitted.

[0118] <Wearing method 4> 38, the mounting unit 2121 of the acoustic signal output device 2100 of wearing method 1 may be replaced with a mounting unit 2224 of a type that can be hooked onto the back side of the upper portion 1022 of the auricle 1020 (like the temples of glasses). The mounting unit 2224 is a rod-shaped member. One end of the mounting unit 2224 is bent so as to be hooked onto the back side of the upper portion 1022 of the auricle 1020, and the other end holds a specific region H1 (first holding region) on the outer wall of the housing 2112. The other end of the mounting unit 2224 may be fixed to the specific region H1 on the outer wall of the housing 2112, or may be integrated into the outer wall of the housing 2112 at the specific region H1. Similarly, the wearing part 2121 of the acoustic signal output device 2100′ of the wearing methods 2 and 3 may be replaced with a wearing part 2224 of a type that can be hooked onto the back side of the upper part 1022 of the auricle 1020. There are no limitations on the material that can be used to make the wearing part 2224.

[0119] <Wearing method 5> 39A , the wearing unit 2122 of the acoustic signal output device 2100 of wearing method 1 may be replaced with a wearing unit 2124 (second wearing unit) that clamps an end of the intermediate portion 1023 (second auricle portion) of the auricle 1020. The wearing unit 2124 (second wearing unit) has a fixing unit 2124a (second fixing unit) that clamps an end of the intermediate portion 1023 (second auricle portion) of the auricle 1020, and a support unit 2124b that fixes the fixing unit 2124a (second fixing unit) to the housing 2112. One end of the support unit 2124b holds the end of the fixing unit 2124a, and the other end of the support unit 2124b holds a specific region H2 (second holding region) on the outer wall of the housing 2112. One end of the support portion 2124b may be fixed to an end of the fixing portion 2124a, or 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 portion of the housing 2112, or may be integrated with the outer wall portion of the housing 2112 in the specific region H2. In this way, the support portion 2124b holds the housing 2112 from the outer side (a second outer side different from the first outer side) of the specific region H2 of the wall portion of the housing 2112. In this way, the housing 2112 is held by the attachment part 2121 (first attachment part) at the upper part 1022 of the auricle 1020 from the outer side (first outer side) of region H1 as described above, and is further held by the attachment part 2124 (second attachment part) at the middle part 1023 of the auricle 1020 from the outer side (second outer side different from the first outer side) of region H2. This stabilizes the position of the housing 2112 attached to the auricle 1020. In this case too, the housing 2112 is held by the attachment part 2121 (first attachment part) and the attachment part 2124 (second attachment part) at different parts (upper part 1022 and middle part 1023) of the auricle 1020, so that the burden on the auricle 1020 caused by wearing the housing 2112 can be distributed. Furthermore, the attachment parts 2121, 2124 do not interfere with the temples of glasses or the string of a mask that are hooked onto the back of the auricle 1020. Alternatively, 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 shape.For example, the fixing portion 2124a may be a clip-like clamping mechanism or an integrated leaf spring. There is also no limitation on the material that forms the mounting portion 2124.

[0120] <Wearing method 6> 39B , the wearing part 2121 of the acoustic signal output device 2300 of wearing method 5 may be replaced with a wearing part 2224 of a type that can be hooked onto the back side of the upper part 1022 of the auricle 1020. The configuration of the wearing part 2224 is the same as that of wearing method 4.

[0121] <Wearing method 7> When the housing 2112 is the housing 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 or near the area (shielded area) where the acoustic signal AC1 (first acoustic signal) emitted from the sound holes 121a, 221a (first sound holes) of the housings 12, 12'', 22 is blocked by the attachment parts 2121, 2122, 2123, 2124, 2224 may be made smaller than the opening area of ​​the sound holes 123a, 223a (second sound holes) provided at a position away from the blocked area. As described above, part of the acoustic signal AC1 (first acoustic signal) emitted from the sound holes 121a, 221a (first sound hole) of the housings 12, 12′, 22 is cancelled out by the acoustic signal AC2 (second acoustic signal) emitted from the sound holes 123a, 223a (second sound hole), thereby suppressing sound leakage. Here, the sound pressure of the acoustic signal AC1 (first acoustic signal) leaking to the outside is smaller in the shielded area than in other areas. Accordingly, by reducing the opening area of ​​the sound holes 123a, 223a (second sound hole) provided in or near the shielded area, the sound pressure of the acoustic signal AC1 (first acoustic signal) leaking to the outside can be reduced. This allows a balance to be achieved between the sound pressure distribution of the acoustic signal AC1 (first acoustic signal) leaking into the area and the sound pressure distribution 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 of the acoustic signal AC1 (first acoustic signal) at position P2 (second point) relative to position P1 (first point) is 11 is the attenuation rate η of the acoustic signal due to air propagation at position P2 (second position) relative to position P1 (first position). 21 A predetermined value η smaller than th The sound pressure distribution can be balanced as follows: In this case, the attenuation η of the acoustic signal AC1 (first acoustic signal) at the position P2 (second position) relative to the position P1 (first position) is: 12 is the attenuation of the acoustic signal due to air propagation at position P2 (second position) relative to position P1 (first position), η 22 a predetermined value ω greater than thAs described above, the sound pressure distribution can be balanced. Note that position P1 (first point) here is a predetermined point where the acoustic signal AC1 (first acoustic signal) emitted from the sound hole 221a (first sound hole) arrives. Furthermore, position P2 (second point) here is a predetermined point that is farther from the acoustic signal output device than position P1 (first point). As a result, sound leakage can be effectively suppressed.

[0122] Below, an example will be described in which the housing 2112 is the housing 12 of the first embodiment or its modified example, and this housing 12 (housing 2112) is held in the mounting parts 2121, 2122 of wearing method 1. However, this does not limit the present invention. The housing 2112 may be the housings 12, 12'', 22 exemplified in the second to fourth embodiments and their modified examples, or this housing 12, 12'', 22 may be held in the mounting parts 2121, 2122, 2123, 2124, 2224 of any of wearing methods 2 to 6. In this case as well, the following configuration can be applied.

[0123] 40A, acoustic signal output device 2100 in this case has driver unit 11 that emits acoustic signal AC1 (first acoustic signal) to one side (D1 direction side) and emits acoustic signal AC2 (second acoustic signal) that is an opposite phase signal of acoustic signal AC1 (first acoustic signal) or a signal approximate to the opposite phase signal to the other side (D2 direction side). As described above, wall portions 121, 123 of housing 12 are provided with one or more sound holes 121a (first sound hole) that guide acoustic signal AC1 (first acoustic signal) emitted from driver unit 11 to the outside, and one or more sound holes 123a (second sound hole) that guide acoustic signal AC2 (second acoustic signal) emitted from 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 the 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 the 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 (the D1 direction side) of a space partitioned by an imaginary plane P51 that passes through the 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 arranged on the other side (the D2 direction side) of the space partitioned by the imaginary plane P51. Here, the opening area of ​​the sound hole 123a (second sound hole) provided in or near the shielded area AR51 where the acoustic signal AC1 (first acoustic signal) is shielded by the support part 2121b of the mounting part 2121 (first mounting part) or the support part 2122b of the mounting part 2122 (second mounting part) is made small. That is, as illustrated in FIG. 40B, the sound hole 123a (second sound hole) is assumed to be provided along the aforementioned circumference C1. Also, it is assumed that the surface of the wall part 123 of the housing 12 is equally divided into a plurality of unit area areas (unit area areas C5-1, C5-2, C5-3, and C5-4 in this example) along the circumference C1.In this example, the number of sound holes 123a (second sound holes) provided in the first unit area area (in this example, unit area areas C5-2 and C5-3), which is any one of the unit area areas including the shielded area AR51, is smaller than the number of sound holes 123a (second sound holes) provided in the second unit area area (in this example, unit area areas C5-1 and C5-4), which is any one of the unit area areas not including the shielded area AR51. In this case, the sum of the opening areas of the sound holes 123a (second sound holes) provided in the first unit area area (in this example, unit area areas C5-2 and C5-3), which is any one of the unit area areas including the shielded area AR51, is smaller than the sum of the opening areas of the sound holes 123a (second sound holes) provided in the second unit area area (in this example, unit area areas C5-1 and C5-4), which is any one of the unit area areas not including the shielded area AR51. This makes it possible to effectively suppress sound leakage.

[0124] 41A and 41B, the number of sound holes 123a (second sound holes) provided in a first unit area area (unit area areas C5-2 and C5-3 in this example) that includes shielded area AR51 may be smaller than the number of sound holes 123a (second sound holes) provided in a second unit area area (unit area areas C5-1 and C5-4 in this example) that does not include shielded area AR51, and further, sound holes 123a with a larger opening area than the first unit area may be provided in the second unit area area. Alternatively, the number of sound holes 123a may be equal in the first unit area area and the second unit area area, and the opening area of ​​each sound hole 123a provided in the first unit area may be smaller than the opening area of ​​each sound hole 123a provided in the second unit area. In this case, the sum of the opening areas of the sound holes 123a (second sound holes) provided in the first unit area area (unit area areas C5-2 and C5-3 in this example) is smaller than the sum of the opening areas of the sound holes 123a (second sound holes) provided in the second unit area area (unit area areas C5-1 and C5-4 in this example). This also effectively suppresses sound leakage.

[0125] <Wearing method 8> 42, 43A, and 43B are used to illustrate wearing method 8. As illustrated in Fig. 42 and 43A, acoustic signal output device 2500 of wearing method 8 has housing 2112 that emits an acoustic signal, and wearing part 2221 that holds housing 2112 and is configured to be worn on auricle 1020.

[0126] The wearing part 2221 includes a fixing part 2221a having a concave inner wall surface 2221aa configured to fit into the upper part 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 of the fixing part 2221a is fitted into the upper part 1022 of the auricle 1020. In this example, the fixing part 2221a has a hollow structure that accommodates at least a portion of the upper part 1022 of the auricle 1020 (e.g., the helix 1022a). In consideration of the load on the auricle 1020, it is desirable that the inner wall surface 2221aa of the fixing part 2221a be a curved surface. However, this is not a limitation of the present invention. The shielding wall 2221b is a plate with a flat or curved wall surface. The shielding wall 2221b in this example is configured in a shape that covers the upper portion 1022 of the auricle 1020 while opening the lower portion 1024 of the auricle 1020 to the outside when the inner wall surface 2221aa of the fixing part 2221a is fitted into the upper portion 1022 of the auricle 1020. In other words, the end 2221c (the end opposite the fixing part 2221a) of the shielding wall 2221b is an opening O51. The opening O51 is provided at a position that opens 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 of the fixing part 2221a. There are also no limitations on the material that may be used to form the attachment part 2221.

[0127] The housing 2112 in this example may be any of the housings 12, 12'', 22 exemplified in the first to fourth embodiments and their modified examples, or may be the housing of a conventional audio signal output device that emits an audio 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 the audio signal is opened in the opposite direction to the inner wall surface 2221bb. When the audio 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 (the auricle 1020). The shielding wall 2221b is positioned so that the shielding wall 2221b faces the ear canal 1020 (the lower part 1024 of the ear canal 1020 side), the sound hole 2112a of the housing 2112 held by the inner wall surface 2221bb faces the ear canal 1021 side, and the housing 2112 does not block the ear canal 1021. In this case, the sound hole 2112a is positioned on the inside side of the shielding wall 2221b, so that the influence of external noise is suppressed and sound leakage of the acoustic signal emitted from the sound hole 2112a can also be suppressed. Furthermore, because the shielding wall 2221b covers only a portion of the ear canal 1020 (the lower part 1024 side of the ear canal 1020 is not blocked), external sounds are not completely blocked and the user can still hear external sounds.

[0128] <Wearing Method 9> 44, the acoustic signal output device 2500' of wearing method 9 is a modified example of the acoustic signal output device 2500 of wearing method 8, in which the wearing section 2221 of the acoustic signal output device 2500 is replaced with a wearing section 2221'. The wearing section 2221' is configured such that the shielding wall 2221b of the wearing section 2221 is replaced with a shielding wall 2221b'. The shielding wall 2221b' is configured in a shape such that when the inner wall surface 2221aa side of the fixing section 2221a is fitted into the upper section 1022 of the auricle 1020, a part of the upper section 1022 of the auricle 1020 is further opened to the outside. That is, the end 2221c of the shielding wall 2221b' (the end opposite the fixed part 2221a) is an opening O51, and furthermore, a part of the shielding wall 2221b' on the fixed part 2221a side is also an opening O52 (through hole). The opening O52 is provided in a position that exposes part of the upper part 1022 of the pinna 1020 to the outside. The rest is the same as in wearing method 8. Because the shielding wall 2221b' covers only part of the pinna 1020 (the lower part 1024 side and part of the upper part 1022 side of the pinna 1020 are not blocked), external sounds are not completely blocked, and the user can still hear external sounds.

[0129] <Wearing method 10> When the housing 2112 is the housing 12, 12", 22 exemplified in the first to fourth embodiments and their modified examples, it is desirable that the sound holes 121a, 221a (first sound holes) of the housings 12, 12", 22 are arranged on the inside side of the shielding wall 2221b, and the sound holes 123a, 223a (second sound holes) are arranged on the outside side of the shielding wall 2221b. This makes it possible to prevent the acoustic signal AC1 from being canceled out by the acoustic signal AC2 on the inside side of the shielding wall 2221b, while also allowing a part of the acoustic signal AC1 (first acoustic signal) leaking out of the shielding wall 2221b to be canceled out by a part 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 audibility of the acoustic signal AC1 by the user.

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

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

[0132] 46B, acoustic signal output device 2600 in this case has driver unit 11 that emits acoustic signal AC1 (first acoustic signal) to one side (D1 direction side) and emits acoustic signal AC2 (second acoustic signal) that is an opposite phase signal of acoustic signal AC1 (first acoustic signal) or a signal approximate to the opposite phase signal to acoustic signal AC1 (first acoustic signal) to the other side (D2 direction side). As described above, wall portions 121, 123 of housing 12 are provided with one or more sound holes 121a (first sound hole) that guide acoustic signal AC1 (first acoustic signal) emitted from driver unit 11 to the outside, and one or more sound holes 123a (second sound hole) that guide acoustic signal AC2 (second acoustic signal) emitted from driver unit 11 to the outside (FIGS. 46B and 46C). 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 illustrated in Fig. 46B, the sound hole 121a (first sound hole) of the housing 12 is disposed on the inner side (D1 direction side) of the shielding wall 2221b, and the sound hole 123a (second sound hole) is disposed on the outer side (D2 direction side) of the shielding wall 2221b. This prevents the acoustic signal AC1 from being canceled out by the acoustic signal AC2 inside the shielding wall 2221b, and allows the portion of the acoustic signal AC1 (first acoustic signal) leaking out of the shielding wall 2221b to be canceled out by the portion of the acoustic signal AC2 emitted from the sound hole 123a (second sound hole). As a result, sound leakage of the acoustic signal AC1 to the outside can be effectively suppressed without significantly reducing the efficiency with which the user can hear the acoustic signal AC1.

[0133] As described above, an opening O51 is provided in a portion of the shielding wall 2221b (toward the end 2221c) that partially exposes a portion of the pinna 1020 (the lower portion 1024) to the outside when the upper portion 1022 of the pinna 1020 is fitted into the inner wall surface 2221aa of the fixing part 2221a (FIGS. 46A and 46B). That is, the opening O51 in this example is provided at a position that exposes the lower portion 1024 of the pinna 1020 to the outside when the upper portion 1022 of the pinna 1020 is fitted into the inner wall surface 2221aa of the fixing part 2221a. Here, the opening area per unit area of ​​the sound hole 123a (second sound hole) that is located on the side where the opening O51 is provided (FIG. 46B) is larger than the opening area per unit area of ​​the sound hole 123a (second sound hole) that is located on the side where the opening is not provided (FIG. 46C). That is, as illustrated in Figures 46B, 46C, and 47A, the sound holes 123a (second sound holes) are provided along the aforementioned circumference C1. Here, it is assumed that the surface of the wall portion 123 of the housing 12 is equally divided into unit area areas (unit area areas C5-1 and C5-2 in this example) along the circumference C1. In this example, the number of sound holes 123a (second sound holes) arranged on the side where the open portion O51 is provided (unit area area C5-1) is greater than the number of sound holes 123a (second sound holes) arranged on the side where no open portion is provided (unit area area C5-2). Therefore, the opening area per unit area of ​​the sound holes 123a (second sound holes) arranged on the side where the open portion O51 is provided (unit area area C5-1) is greater than the opening area per unit area of ​​the sound holes 123a (second sound holes) arranged on the side where no open portion is provided (unit area area C5-2). This allows the sound pressure distribution of the acoustic signal AC2 (second acoustic signal) emitted from the sound holes 123a, 223a (second sound holes) to be closer to the sound pressure distribution of the acoustic signal AC1 leaking outside the shielding wall 2221b, and allows the acoustic signal AC2 to appropriately cancel out the acoustic signal AC1, effectively suppressing sound leakage.

[0134] 47B, the average value of the opening area of ​​the sound holes 123a (second sound holes) arranged on the side where the open portion O51 is provided (unit area area C5-1) may be larger than the average value of the opening area of ​​the sound holes 123a (second sound holes) arranged on the side where the open portion O51 is provided (unit area area C5-2). Alternatively, as shown in Fig. 48A, on the side where the open portion O51 is provided (unit area area C5-1), sound holes 123a (second sound holes) may be arranged in pairs at equal intervals in the direction of the circumference C1 in a direction perpendicular to the circumference C1, and on the side where the open portion is not provided (unit area area C5-2), one sound hole 123a (second sound hole) may be arranged in pairs at equal intervals in the direction of the circumference C1. 48B, sound hole 123a (second sound hole) may be arranged on the side where opening O51 is provided (unit area region C5-1), but sound hole 123a (second sound hole) may not be arranged on the side where no opening is provided (unit area region C5-2). Even in this case, sound leakage can be effectively suppressed.

[0135] [Sixth embodiment] In the sixth embodiment, another wearing method of an ear-mounted acoustic signal output device will be illustrated.

[0136] <Wearing method 11> As in the acoustic signal output device 3100 illustrated in FIG. 49A, the acoustic signal output device 2100 of the wearing method 1 may have a configuration in which the wearing unit 2121 is omitted.

[0137] <Wearing method 12> As in the acoustic signal output device 3200 illustrated in FIG. 49B, the wearing section 2123 of the acoustic signal output device 2100 of wearing method 1 may be omitted, and the housing 2112 may be any of the housings 12, 12'', and 22 described above. However, in this example, when the acoustic signal output device 3200 is worn 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 ear canal 1021.

[0138] <Wearing method 13> As in the acoustic signal output device 3300 illustrated in FIG. 50A, the wearing section 2121 of the acoustic signal output device 2300 of wearing method 5 may be omitted, and the housing 2112 may be any of the housings 12, 12", and 22 described above. In this example, when the acoustic signal output device 3300 is worn on the auricle 1020, the sound holes 121a and 221a of the housings 12, 12", and 22 are configured to face the ear canal 1021 side.

[0139] <Wearing Method 14> 50B, the wearing unit 2221 of the acoustic signal output device 2500 of Wearing Method 8 may be replaced with a wearing unit 2221'. The wearing unit 2221' includes a shielding wall 2221b configured to cover only the upper portion 1022 of the auricle 1020 when the inner wall surface side of the fixing part 2221a is fitted into the upper portion 1022 of the auricle 1020. Furthermore, an end 2221c' of the shielding wall 2221b is configured in a curved shape, 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] <Wearing method 15> As in the acoustic signal output device 4100 illustrated in FIG. 51A, the acoustic signal output device 2200 of the wearing method 4 may have a configuration in which the wearing unit 2122 is omitted.

[0141] <Wearing Method 16> 51B, an acoustic signal output device 4100' may be configured such that the wearing unit 2122 of the acoustic signal output device 2200 of wearing method 4 is omitted, and a wearing unit 4421 is provided that is configured to come into contact with the cavity of the concha 1025 of the auricle 1020 when worn. One end of the wearing unit 4421 holds the housing 2112, and the other end of the wearing unit 4421 is configured in a shape that can support the cavity of the concha 1025 so as not to block the ear canal. This allows for more stable wearing.

[0142] <Wearing Method 17> The acoustic signal output device 4200 illustrated in FIG. 52A has a housing 2112, a columnar attachment part 4210 that holds the housing 2112 and is configured to be positioned at the base of the auricle 1020 when worn, and an arc-shaped attachment part 4220 that is held at both ends of the attachment part 4210 and is worn in the area from the back side of the upper part 1022 of the auricle 1020 to the lower part 1024.

[0143] <Wearing Method 18> As in the acoustic signal output device 4300 illustrated in FIG. 52B, the wearing section 2122 of the acoustic signal output device 2200 of wearing method 4 may be omitted, and the housing 2112 may be any of the housings 12, 12'', and 22 described above. However, in this example, when the acoustic signal output device 4300 is worn 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 ear canal 1021.

[0144] <Wearing Method 19> An acoustic signal output device 5110 of wearing method 19 illustrated in FIGS. 53A to 53E includes a housing 5111 that emits an acoustic signal and a mounting part 5112 that holds the housing 5111 and is hooked onto the back side 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 of the mounting part 5112 so as to be rotatable in the R5 direction. As illustrated in FIG. 53E, the housing 5111 is worn without blocking the ear canal, with the sound hole through 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, because the housing 5111 can be rotated in the R5 direction relative to one end of the mounting part 5112, the wearing position and the position of the sound hole can be adjusted to suit the size and shape of the individual auricle 1020.

[0145] <Wearing Method 20> 54A to 54C show an acoustic signal output device 5120 of wearing method 20, which includes a housing 5121 that emits an acoustic signal and a mounting part 5122 that holds the housing 5121 and is hooked onto the underside of the upper part 1022 of the auricle 1020 when worn. Unlike wearing method 19, the housing 5121 is not rotatable relative to the mounting part 5122. As shown in FIG. 54C, the housing 5121 does not block the ear canal and is worn with the sound hole through 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] <Wearing Method 21> Acoustic signal output devices 5130, 5140 of wearing method 21 shown in Figures 55A and 55B each have housings 5131, 5141 that emit acoustic signals, and wearing parts 5132, 5142 that hold the housings 5131, 5141 and are hooked onto the back side of the upper part 1022 of the auricle 1020 when worn. Furthermore, the acoustic signal output device 5140 shown in Figure 55B is provided with a wearing part 5143 that is configured to come into contact with the cavity of the concha 1025 of the auricle 1020 when worn. This allows for more stable wearing.

[0147] <Wearing method 22> 56A, 56B, and 56C includes a housing 5151 that emits an acoustic signal, a rod-shaped attachment part 5152 that holds the housing 5151 and is hooked onto the back side of the upper part 1022 of the auricle 1020 when worn, a columnar support part 5154 that holds the housing 5151 at one end and the attachment part 5152 at the other end, a rod-shaped attachment part 5153 that is hooked onto the back side of the middle part 1023 and the upper part 1022 of the auricle 1020 from the middle part 1023 side when worn, and a columnar support part 5155 that holds the housing 5151 at one end and the attachment part 5153 at the other end. As shown in FIG. 56C, the housing 5151 is worn without blocking the ear canal, with the sound hole through which the acoustic signal is emitted facing the ear canal. At this time, the auricle 1020 is sandwiched between the housing 5151 and the attachment parts 5152 and 5153 , and thus the acoustic signal output device 5150 is fixed to the auricle 1020 .

[0148] <Wearing method 23> 57A to 57E includes a housing 5161 that emits an acoustic signal, a columnar mounting part 5164 that holds the housing 5161 and is configured to be positioned at the base of the auricle 1020 when worn, a rod-shaped mounting part 5162 that is held at one end of the mounting part 5164 and that can be hooked onto the back side of the upper part 1022 of the auricle 1020 when worn, and a rod-shaped mounting part 5163 that is held at the other end of the mounting part 5164 and that can be hooked onto the back side of the lower part 1024 of the auricle 1020 when worn. As shown in Fig. 57E, the housing 5161 is worn with the sound hole that emits the acoustic signal facing the ear canal without blocking the ear canal. At this time, the auricle 1020 is sandwiched between the housing 5161 and the attachment portion 5164 and the attachment portions 5162 and 5163 , and thus the acoustic signal output device 5160 is fixed to the auricle 1020 .

[0149] <Wearing Method 24> 58A to 58D and 59A to 59D each include housings 5171, 5181 that emit acoustic signals, columnar mounting sections 5172, 5182 configured to be positioned behind intermediate section 1023 of pinna 1020 when worn, and curved, strip-shaped support sections 5173, 5183 that hold housings 5171, 5181 at one end and mounting sections 5172, 5182 at the other end. As shown in Fig. 58D and 59D, housings 5171, 5181 are worn with the sound hole through which the acoustic signal is emitted facing the ear canal without blocking the ear canal. At this time, the auricle 1020 is sandwiched between the housings 5171 and 5181 and the attachment parts 5172 and 5182 , and as a result, the acoustic signal output devices 5170 and 5180 are fixed to the auricle 1020 .

[0150] <Wearing Method 25> 60A to 60C includes a housing 5191 that emits an acoustic signal, and a rod-shaped attachment part 5192 that holds the housing 5191 and is configured to be positioned behind the auricle 1020 when worn. The attachment part 5192 holds the housing 5191 at one end that is positioned on the lower part 1024 of the auricle 1020 when worn. As shown in FIG. 60C, the housing 5191 is worn without blocking the ear canal, with the sound hole through which the acoustic signal is emitted facing the ear canal. At this time, the auricle 1020 is sandwiched between the housing 5191 and the attachment part 5192, thereby fixing the acoustic signal output device 5190 to the auricle 1020.

[0151] <Wearing Method 26> 61A to 61E includes a housing 5201 that emits an acoustic signal and an annular attachment part 5202 that holds the housing 5201. As shown in FIG. 61E, the housing 5201 is attached without blocking the ear canal, with the sound hole through which the acoustic signal is emitted facing the ear canal. When attached, the auricle 1020 is inserted into the annular attachment part 5202, and the attachment part 5202 is positioned behind the upper part 1022, middle part 1023, and lower part 1024 of the auricle 1020. At this time, the auricle 1020 is sandwiched between the housing 5201 and the attachment part 5202, whereby the acoustic signal output device 5200 is fixed to the auricle 1020.

[0152] <Wearing 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'', 22 exemplified in the first to fourth embodiments and their modified examples is fixed to the temples of glasses.

[0153] 62A and 62B, one end of a support portion 5312 is held in the middle of a temple 5311, and the other end of the support portion 5312 holds a housing 12. In both of the acoustic signal output devices 5310 and 5320, the temple 5311 is disposed behind the upper portion 1022 of the pinna 1020 when worn. However, in the acoustic signal output device 5310 shown in FIG. 62A, the opening direction of the sound hole 121a of the housing 12 is tilted with respect to the ear canal 1021 when worn. On the other hand, in the example of the acoustic signal output device 5320 shown in FIG. 62B, the sound hole 121a of the housing 12 is disposed facing the ear canal 1021 when worn.

[0154] 63A and 63B, the housing 12 is held directly by the middle of the temples 5311. In both of the acoustic signal output devices 5340 and 5350, the temples 5311 are positioned behind the upper portions 1022 of the pinna 1020 when worn. However, in the acoustic signal output device 5340 shown in Fig. 63A, the housing 12 is held by the temples 5311 so that the opening direction of the sound holes 121a in the housing 12 is approximately perpendicular to the temples 5311, and the housing 12 is positioned so that the opening direction of the sound holes 121a in the housing 12 is approximately perpendicular to the ear canal 1021 when worn. On the other hand, in the acoustic signal output device 5350 illustrated in Figure 63B, the housing 12 is held by the temple 5311 so that the opening direction of the sound hole 121a of the housing 12 is approximately parallel to the temple 5311, and when worn, the opening direction of the sound hole 121a of the housing 12 is positioned so that it faces the upper part 1022 of the auricle 1020.

[0155] 64A and 64B, the acoustic signal output devices 5360 and 5370 hold the housing 12 directly at the tips of the temples 5361 and 5371. When both acoustic signal output devices 5360 and 5370 are worn, the temples 5361 are disposed behind the upper part 1022 of the auricle 1020. However, when worn, the acoustic signal output device 5360 shown in FIG. 64A is disposed so that the opening direction of the sound hole 121a of the housing 12 faces from the base of the lower part 1024 of the auricle 1020 toward the ear canal 1021. When worn, the acoustic signal output device 5370 shown in FIG. 64B is disposed so that the opening direction of the sound hole 121a of the housing 12 faces from the outside of the lower part 1024 of the auricle 1020 toward the ear canal 1021.

[0156] <Wearing Method 28> Alternatively, as in acoustic signal output device 5380 illustrated in FIG. 65A, any one of the casings 12, 12'', and 22 illustrated in the first to fourth embodiments and their modified examples may be fixed to a rod-shaped attachment section 5381 curved into a shape so as to be worn on the neck or shoulders of user 1000. Furthermore, as in acoustic signal output device 5390 illustrated in FIG. 65B, any one of the casings 12, 12'', and 22 may be fixed to a rod-shaped attachment section 5391 curved into a shape so as to be worn on the top of the head of user 1000. Furthermore, as in acoustic signal output device 5400 illustrated in FIG. 65C, any one of the casings 12, 12'', and 22 may be fixed to a rod-shaped attachment section 5401 curved into a shape so as to be worn on the back of the head and auricle 1020 of user 1000.

[0157] <Other wearing methods> Alternatively, the wearing method of existing open-ear earphones may be applied to the acoustic signal output devices 4, 4', 10, 20, and 30 illustrated in the first to fourth embodiments and their modified examples. For example, as illustrated in Reference 1 (https: / / www.sony.jp / headphone / products / STH40D / feature_1.html), a ring body serving as a stopper may be added to the D1 direction side of the housings 12, 12", and 22 or the acoustic signal output units 40-1 and 40-2, and a U-shaped wearing part may be added to the side of the housings 12, 12", and 22 or the acoustic signal output units 40-1 and 40-2 opposite to the D1 direction. In this case, the ring-shaped body is placed around the outer ear canal (for example, the concha), and the lower part of the pinna is sandwiched between the U-shaped attachment part, thereby attaching the housings 12, 12", 22 or the acoustic signal output parts 40-1, 40-2 to the pinna. In particular, when applying the attachment method of Reference Document 1 to the acoustic signal output device 20 of the second embodiment, a ring-shaped body acting as a stopper can be added to the D1 side of the housing 22, and the U-shaped attachment part added to the D2 side of the housing 22 can be configured to also serve as the waveguides 24, 25 and the housing 23 (FIG. 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 formed in a substantially elliptical cylindrical shape, and a J-shaped attachment part may be provided on the housings 12, 12", 22 or the acoustic signal output units 40-1, 40-2. In this case, the D1 direction side of the housings 12, 12", 22 or the acoustic signal output units 40-1, 40-2 is placed against the front side (external ear canal side) of the upper part of the auricle, and the J-shaped attachment part is hooked onto the back side of the upper part of the auricle, thereby attaching the housings 12, 12", 22 or the acoustic signal output units 40-1, 40-2 to the auricle.

[0159] For example, as illustrated in Reference 3 (https: / / ambie.co.jp / soundearcuffs / tws / ), the housings 12, 12", 22 or the acoustic signal output units 40-1, 40-2 may be configured in a substantially spherical shape, and the side of the housings 12, 12", 22 or the acoustic signal output units 40-1, 40-2 opposite the D1 direction may be held by one end of a C-shaped attachment part. The other end of this C-shaped attachment part may also be configured in a substantially spherical shape. In this case, the D1 direction side of the housings 12, 12", 22 or the acoustic signal output units 40-1, 40-2 is placed against the periphery of the external auditory canal (for example, the concha), and the C-shaped attachment part grips (sandwiches) the middle part of the concha, thereby attaching the housings 12, 12", 22 or the acoustic signal output units 40-1, 40-2 to the concha.

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

[0161] For example, as exemplified in Reference 5 (https: / / www.audio-technica.co.jp / product / ATH-EW9), a semicircular attachment portion (ear hanger) may be provided that has an adjustment mechanism (slide fit mechanism) for adjusting the position of the attached housings 12, 12", 22 or acoustic signal output units 40-1, 40-2 relative to the auricle. In this case, the D1 direction side of housings 12, 12", 22 or acoustic signal output units 40-1, 40-2 is placed against the front side of the upper part of the auricle, and the semicircular attachment portion is hooked onto the underside of the upper part of the auricle, thereby attaching housings 12, 12", 22 or acoustic signal output units 40-1, 40-2 to the auricle. By operating the adjustment mechanism in this state, the position of the attached housings 12, 12", 22 or acoustic signal output units 40-1, 40-2 relative to the auricle can be adjusted.

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

[0163] [Other modifications, etc.] It should be noted that the present invention is not limited to the above-described embodiments. For example, in the above-described embodiments and their modified examples, the present invention is applied to a device for listening to sound that is worn on the ear without sealing the ear canal of the user (e.g., open-ear earphones, headphones, etc.). However, this does not limit the present invention, and the present invention may also be applied to a device for listening to sound that is worn on a body part other than the ear without sealing the ear canal of the user, such as a bone conduction earphone or a neck speaker earphone.

[0164] Additionally, for example, the present invention may be used as an acoustic signal output device capable of controlling the attenuation rate of an acoustic signal emitted to the outside without providing a sound-absorbing material in the sound hole through which the acoustic signal emitted from the driver unit passes. Also, for example, the present invention may be used as an acoustic signal output device capable of attenuating an acoustic signal emitted from a driver unit so that it cannot be heard at a predetermined position without performing directional control using a physical shape or signal processing. Also, for example, the present invention may be used as an acoustic signal output device capable of attenuating an acoustic signal at a point where the acoustic signal is to be attenuated 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 an acoustic signal in a specific local area without covering the periphery of that local area with a 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 unit 113 Vibration plate 12,12”,22,23,2112,5021,5111,5121,5131,5151,5161,5171,5191,5201 Housing 121a,123a,221a,223a sound hole 13 Sound-absorbing material 24,25 Waveguide 31,41 Circuit section 40-1, 40-2 Acoustic signal output section AC1,AC2 acoustic signal AR21,AR22 hollow part C1 Circumference C1-1, C1-2, C1-3, C1-4 Unit arc area MAC1, MAC2 monaural 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, The housing and a curved mounting portion to which the housing is fixed; a driver unit housed in the housing; a first end surface disposed on one side of the driver unit; a second end surface disposed on the other side of the driver unit; a side surface surrounding a space sandwiched between the first end surface and the second end surface, the side surface being centered on an imaginary axis passing through the first end surface and the second end surface; the driver unit is configured to emit a first acoustic signal to one side and a second acoustic signal that is an inverse phase signal of the first acoustic signal or a signal approximating the inverse phase signal to the other side; The driver unit has a substantially cylindrical shape, a first sound hole for guiding the first acoustic signal to the outside; a second sound hole for emitting the second acoustic signal to the outside, the first sound hole is provided in the first end surface, The second sound hole is provided on the side surface. Acoustic signal output device.

2. The second sound hole is provided on the side surface closer to the second end surface.

2. The acoustic signal output device according to claim 1.

3. No sound hole is provided on the second end surface.

3. The acoustic signal output device according to claim 2.

4. the imaginary axis is an axis passing through a central region of the housing, the first sound hole is disposed on the imaginary axis line or in the vicinity of the imaginary axis line.

4. The acoustic signal output device according to claim 3.

5. a plurality of the second sound holes are provided along a circumference centered on the virtual axis line; 5. The acoustic signal output device according to claim 4.

6. A sheet-like echo suppression material is fixed inside the housing.

6. The acoustic signal output device according to claim 5.

7. There are a plurality of second sound holes, Any of the plurality of second sound holes is filled with a sound-absorbing material.

7. The acoustic signal output device according to claim 6.

8. The attenuation rate of the first acoustic signal at a second point farther from the acoustic signal output device than a predetermined first point where the first acoustic signal arrives is designed to be equal to or less than a predetermined value that is smaller than the attenuation rate of the acoustic signal due to air propagation at the second point relative to the first point, or The attenuation amount of the first acoustic signal at the second point relative to the first point is designed to be equal to or greater than a predetermined value that is greater than the attenuation amount of the acoustic signal at the second point relative to the first point due to air propagation.

8. The acoustic signal output device according to claim 7.

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