Acoustic signal output device

Abstract

The present invention provides an acoustic signal output device comprising: a concave reflector having a surface having a paraboloid of revolution or similar to a paraboloid of revolution on the inner side; and a first driver unit disposed on the inner side of the reflector. A cutout portion that opens the inner side of the reflector toward the outer side is provided in a portion of the open end side of the reflector. A first acoustic signal is emitted from the first driver unit to one side, and a second acoustic signal is emitted from the first driver unit to the other side. The invention relates to an audio signal output device. The attenuation rate of the first acoustic signal at a second point farther from the acoustic signal output device than a predetermined first point at which the first acoustic signal arrives is less than or equal to a predetermined value that is less than the attenuation rate caused by air transmission of the acoustic signal at the second point with the first point as a reference. Furthermore, the acoustic signal output device is designed such that the attenuation amount of the first acoustic signal at a second point, which is based on the first point, is greater than or equal to a predetermined value that is greater than the attenuation amount caused by air transmission of the acoustic signal at the second point, which is based on the first point.

Description

Technical Field

[0001] The present invention relates to an audio signal output device, and particularly to an audio signal output device that does not seal the external auditory canal. Background Art

[0002] In recent years, the increased burden on the ears caused by wearing earphones and headphones has become a problem. As a device for reducing the burden on the ears, open-ear earphones and headphones that do not block the external auditory canal are known.

[0003] Prior Art Documents

[0004] Non-Patent Documents

[0005] Non-Patent Document 1: "WHAT ARE OPEN-EAR HEADPHONES?", [online], Bose Corporation, [searched on September 7, 2022], Internet <https: / / www.bose.com / en_us / better_with_bose / open-ear-headphones.html> Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] However, open-ear earphones and headphones have a problem of significant sound leakage to the surroundings. Such a problem is not limited to open-ear earphones and headphones, but is a common problem in audio signal output devices that do not seal the external auditory canal, including mounted speakers, embedded speakers, etc.

[0008] The present invention has been completed in view of such points, and an object thereof is to provide an audio signal output device that does not seal the external auditory canal and can suppress sound leakage to the surroundings.

[0009] Means for Solving the Problems

[0010] The present invention provides an audio signal output device, which includes: a concave reflector having a surface of a rotating paraboloid or approximately a rotating paraboloid on the inner side; and a first driver unit disposed inside the reflector. Here, a cutout portion that opens the inner side of the reflector to the outside is provided at a part of the open end side of the reflector. The audio signal emitted from the first driver unit to one side is taken as a first audio signal, and the audio signal emitted from the first driver unit to the other side is taken as a second audio signal. The audio signal output device is designed such that, when the first audio signal is emitted from one side of the first driver unit and the second audio signal is emitted from the other side of the first driver unit, the attenuation rate of the first audio signal at a second location farther from the audio signal output device than a predetermined first location where the first audio signal arrives becomes less than a predetermined value of the attenuation rate caused by air transmission of the audio signal at the second location based on the first location. Alternatively, the audio signal output device is designed such that, in this case, the attenuation amount of the first audio signal at the second location based on the first location becomes greater than a predetermined value of the attenuation amount caused by air transmission of the audio signal at the second location based on the first location.

[0011] Advantages of the Invention

[0012] According to this structure, leakage of sound to the surroundings can be suppressed. Description of the Drawings

[0013] Figure 1 is a perspective front view illustrating the structure of the audio signal output device of the first embodiment.

[0014] Figure 2 is a perspective top view illustrating the structure of the audio signal output device of the first embodiment.

[0015] Figure 3 is Figure 1 a sectional view taken along line 1-1.

[0016] Figure 4 is Figure 2 a sectional view taken along line 2-2.

[0017] Figure 5 is a conceptual diagram for illustrating the arrangement of sound holes.

[0018] Figure 6 is a conceptual diagram for explaining the relationship between the rotating paraboloid and the focus.

[0019] Figure 7A is a conceptual diagram for explaining the traveling direction of the audio signal when the driver unit is arranged at the focus of the rotating paraboloid. Figure 7BIt is a conceptual diagram for explaining the traveling direction of the audio signal when the drive unit is not configured at the focus of the paraboloid of revolution.

[0020] Figure 8A It is a conceptual diagram for exemplifying the structure of mounting a speaker on the drive unit. Figure 8B It is a conceptual diagram for exemplifying the configuration structure of the audio signal output device of the first embodiment.

[0021] Figure 9A It is a block diagram for exemplifying the functional structure of supplying a signal to the drive unit. Figure 9B It is a diagram exemplifying the sound pressure level at the observation point.

[0022] Figure 10A And Figure 10B It is a chart for exemplifying the directivity characteristics of the audio signal output device.

[0023] Figure 11A And Figure 11B It is a chart for exemplifying the directivity characteristics of the audio signal output device.

[0024] Figure 12 It is a chart for exemplifying the directivity characteristics of the audio signal output device.

[0025] Figure 13A And Figure 13B It is a chart for exemplifying the frequency characteristics of the audio signal output device.

[0026] Figure 14A And Figure 14B It is a chart for exemplifying the frequency characteristics of the audio signal output device.

[0027] Figure 15 It is a chart for exemplifying the frequency characteristics of the audio signal output device.

[0028] Figure 16 It is a front view for exemplifying a modified example of the arrangement of the sound holes.

[0029] Figure 17 It is a front view for exemplifying a modified example of the arrangement of the sound holes.

[0030] Figure 18 It is a perspective front view exemplifying the structure of the audio signal output device of a modified example of the first embodiment.

[0031] Figure 19 It is a perspective top view exemplifying the structure of the audio signal output device of a modified example of the first embodiment.

[0032] Figure 20A It is a perspective top view exemplifying the constitution of the housing of a modified example of the first embodiment. Figure 20BIs a perspective front view showing the structure of the housing of a modified example of the first embodiment. Figure 20C Is a bottom view showing the structure of the housing of a modified example of the first embodiment.

[0033] Figure 21 Is Figure 19 The 19-19 sectional view of.

[0034] Figure 22A And Figure 22B Is a sectional view for illustrating the structure of the audio signal output device of a modified example of the first embodiment.

[0035] Figure 23 Is a perspective front view showing the structure of the audio signal output device of the second embodiment.

[0036] Figure 23 Is a perspective top view showing the structure of the audio signal output device of the second embodiment.

[0037] Figure 25 Is a perspective front view showing the structure of the audio signal output device of a modified example of the second embodiment.

[0038] Figure 26 Is a perspective front view showing the structure of the audio signal output device of a modified example of the second embodiment.

[0039] Figure 27A Is a graph for illustrating the frequency characteristics of the audio signal observed on one side of the cutout portion. Figure 27B Is a graph for illustrating the frequency characteristics of the audio signal observed on the side where the cutout portion is not provided.

[0040] Figure 28A Is a graph for illustrating the frequency characteristics of the audio signal observed on one side of the cutout portion and on the side where the cutout portion is not provided. Figure 28B Is a graph for illustrating the difference in the frequency characteristics of the audio signal due to the difference in the cutout portion.

[0041] Figure 29 Is a perspective front view showing the structure of the audio signal output device of the third embodiment.

[0042] Figure 30A Is a block diagram for illustrating the functional structure of supplying a signal to the driver unit. Figure 30B Is a graph illustrating the sound pressure level at the observation point. Detailed implementation manners

[0043] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0044] [First embodiment]

[0045] First, a first embodiment of the present invention will be described.

[0046] <Structure>

[0047] The audio signal output device 10 of the present embodiment is a device for listening to audio that is worn without enclosing the user's external auditory canal (for example, open (open-type) headphones, over-ear headphones, etc., mounted speakers, embedded speakers, etc.). As Figures 1 to 4 illustrated, the audio signal output device 10 of the present embodiment includes: a concave (for example, parabolic shape) reflector 13 having a paraboloid of revolution or a surface approximate to the paraboloid of revolution on the inner side; driver units 11, 15 (speaker driver units, drivers) that convert an output signal (an electrical signal representing an audio signal) output from a playback device into an audio signal and output it; a housing 16 that houses the driver unit 15 inside; and a support portion 14 for arranging the driver unit 11 inside the reflector 13.

[0048] <Driver unit 11 (first driver unit)>

[0049] In the present embodiment, the frequency band of the played audio signal (played audio signal) is divided into a high-frequency band and a low-frequency band, and the driver unit 11 emits the audio signal on the high-frequency band side of the played audio signal. That is, the driver unit 11 processes the audio signal that is mainly high-frequency in the played audio signal. The output signal output from the playback device is separated into a high-frequency band signal on the high-frequency side and a low-frequency band signal on the low-frequency side that is lower than it. The separated high-frequency band signal is input to the driver unit 11. In addition, the frequency bands where the levels of the high-frequency band signal and the low-frequency band signal are above a specified value may overlap or may not overlap with each other. The driver unit 11 is a device (a device having a speaker function) that emits (plays) the audio signal AC1 (first audio signal) based on the input high-frequency band signal to one side (the D1 direction side) and emits the inverted phase signal (phase-inverted signal) of the audio signal AC1 or the audio signal AC2 (second audio signal) that is an approximate signal of the inverted phase signal to the other side (the D2 direction side). That is, the audio signal emitted from the driver unit 11 to one side (the D1 direction side) is referred to as the audio signal AC1 (first audio signal), and the audio signal emitted from the driver unit 11 to the other side (the D2 direction side) is referred to as the audio signal AC2 (second audio signal). For example, the driver unit 11 is arranged along the axis A1 (axis) extending in the D1 direction or near the axis A1 (axis), and the audio signals AC1, AC2 are emitted along the axis A1 (axis). For example, the driver unit 11 includes a diaphragm 113 ( Figure 1) The vibrating plate 113 emits the audio signal AC1 from one surface 113a toward the D1 direction side by vibration, and emits the audio signal AC2 from the other surface 113b toward the D2 direction side by this vibration. For example, the vibrating plate 113 is disposed near the axis A1 (axis) or the axis A1 (axis). In the example, the drive unit 11 vibrates based on the input output signal through the vibrating plate 113, emits the audio signal AC1 from one side surface 111 toward the D1 direction side, and emits the audio signal AC2, which is an inverted signal of the audio signal AC1 or an approximate signal of the inverted signal, from the other side 112 toward the D2 direction side. That is, the audio signal AC2 is an audio signal that is emitted incidentally with the emission of the audio signal AC1. In addition, the D2 direction (the other side) is, for example, the opposite direction of the D1 direction (one side), but the D2 direction does not need to be strictly the opposite direction of the D1 direction, 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 the drive unit 11. In addition, depending on the type and shape of the drive unit 11, sometimes the audio signal AC2 strictly becomes the inverted signal of the audio signal AC1, and sometimes the audio signal AC2 becomes an approximate signal of the inverted signal of the audio signal AC1. For example, the approximate signal of the inverted signal of the audio signal AC1 can be either (1) a signal obtained by shifting the phase of the inverted signal of the audio signal AC1, (2) a signal obtained by changing (amplifying or attenuating) the amplitude of the inverted signal of the audio signal AC1, or (3) a signal obtained by shifting the phase of the inverted signal of the audio signal AC1 and further changing the amplitude. The phase difference between the inverted signal of the audio signal AC1 and its approximate signal is preferably δ1% or less of one cycle of the inverted signal of the audio signal AC1. Examples of δ1% are 1%, 3%, 5%, 10%, 20%, etc. In addition, the difference between the amplitude of the inverted signal of the audio signal AC1 and the amplitude of its approximate signal is preferably δ2% or less of the amplitude of the inverted signal of the audio signal AC1. Examples of δ2% are 1%, 3%, 5%, 10%, 20%, etc. In addition, as the type of the drive unit 11, a dynamic type, a balanced armature type, a hybrid type of the dynamic type and the balanced armature type, a capacitive type, etc. can be exemplified. In addition, the shapes of the drive unit 11 and the vibrating plate 113 are not limited. In the present embodiment, for the sake of simplicity of explanation, an example is shown in which the outer shape of the drive unit 11 is a substantially cylindrical shape having two end faces, and the vibrating plate 113 is a substantially disc shape, but this does not limit the present invention. For example, the outer shape of the drive unit 11 can also be a rectangular parallelepiped shape, etc., and the vibrating plate 113 can also be a dome shape, etc. In addition, examples of the audio signal are sounds such as music, voices, sound effects, environmental sounds, etc.

[0050] <Drive unit 15 (second drive unit)>

[0051] The drive unit 15 of this embodiment is arranged on the D2 direction side of the drive unit 11. The drive unit 15 is larger in size than the drive unit 11 and emits the audio signal on the low-frequency band side of the above playback audio signal. That is, the drive unit 15 mainly processes the low-frequency audio signal in the playback audio signal. Thus, compared with the case of using only the drive unit 11, a lower-frequency sound pressure can be obtained. As described above, the low-frequency band signal separated from the output signal is input to the drive unit 15, and the drive unit 15 is a device (a device with a speaker function) that emits (plays) the audio signal AC3 (the third audio signal) based on the input low-frequency band signal to one side (the D1 direction side) and emits the inverted phase signal (phase-inverted signal) of the audio signal AC3 or the audio signal AC4 (the fourth audio signal) that is an approximate signal of the inverted phase signal to the other side (the D2 direction side). That is, the audio signal emitted from the drive unit 15 to one side (the D1 direction side) is called the audio signal AC3 (the third audio signal), and the audio signal emitted from the drive unit 15 to the other side (the D2 direction side) is called the audio signal AC4 (the fourth audio signal). For example, the drive unit 15 is arranged near the axis A1 (axis) or on the axis A1 (axis), and the audio signals AC3 and AC4 are emitted along the axis A1 (axis). The drive unit 15 includes a diaphragm 153 (the second diaphragm) ( Figure 12) The diaphragm 153 emits the audio signal AC3 (third audio signal) from one surface 153a toward the D1 direction side (one side) through vibration, and emits the audio signal AC4 (fourth audio signal) from the other surface 153b toward the D2 direction side (the other side) through the vibration. For example, the diaphragm 153 is disposed near the axis A1 (axis). In the driver unit 15 of this example, the diaphragm 153 vibrates based on the input output signal, emits the audio signal AC3 from the surface 151 on one side toward the D1 direction side, and emits the audio signal AC4, which is an inverted signal of the audio signal AC3 or an approximate signal of the inverted signal, from the surface 152 on the other side toward the D2 direction side. That is, the audio signal AC4 is an audio signal emitted incidentally along with the emission of the audio signal AC3. The audio signal AC3 is an in-phase signal of the audio signal AC1 or an approximate signal of the in-phase signal, and the audio signal AC4 is an in-phase signal of the audio signal AC2 or an approximate signal of the in-phase signal. In addition, depending on the type and shape of the driver unit 15, sometimes the audio signal AC4 strictly becomes an inverted signal of the audio signal AC3, and sometimes the audio signal AC4 becomes an approximate signal of the inverted signal of the audio signal AC3. For example, the approximate signal of the inverted signal of the audio signal AC3 may be (1) a signal obtained by shifting the phase of the inverted signal of the audio signal AC3, may be (2) a signal obtained by changing (amplifying or attenuating) the amplitude of the inverted signal of the audio signal AC3, or may be (3) a signal obtained by shifting the phase of the inverted signal of the audio signal AC3 and further changing the amplitude. The phase difference between the inverted signal of the audio signal AC3 and its approximate signal is preferably δ3% or less of one cycle of the inverted signal of the audio signal AC3. Examples of δ3% are 1%, 3%, 5%, 10%, 20%, etc. In addition, the difference between the amplitude of the inverted signal of the audio signal AC3 and the amplitude of its approximate signal is preferably δ4% or less of the amplitude of the inverted signal of the audio signal AC3. Examples of δ4% are 1%, 3%, 5%, 10%, 20%, etc. In addition, as the type of the driver unit 15, a dynamic type, a balanced armature type, a hybrid type of the dynamic type and the balanced armature type, a capacitive type, etc. can be exemplified. In addition, the shapes of the driver unit 15 and the diaphragm 153 are not limited. In the present embodiment, for simplicity of explanation, an example is shown in which the outer shape of the driver unit 15 is a substantially cylindrical shape having both end faces, and the diaphragm 153 is a substantially disc shape, but this does not limit the present invention. For example, the outer shape of the driver unit 15 may also be a rectangular parallelepiped shape, etc., and the diaphragm 153 may also be a dome shape, etc.

[0052] As described above, the driver unit 15 is larger in size than the driver unit 11. For example, if the diameter of the driver unit 11 (the diameter in the direction orthogonal to the D1 direction and / or the D2 direction) is set as S11, and the diameter of the driver unit 15 (the diameter in the direction orthogonal to the D1 direction and / or the D2 direction) is set as S21, then S21 > S11 is satisfied. For example, S21 is more than twice S11, S11 is 12 mm, and S21 is 35 mm. Additionally, for example, if the diameter of the diaphragm 113 (the diameter in the D1 direction and / or the direction orthogonal to the D2 direction) is set as S12, and the diameter of the diaphragm 153 (the diameter in the D1 direction and / or the direction orthogonal to the D2 direction) is set as S22, then S22 > S12 is satisfied. For example, S22 is more than twice S12, S12 is 10 mm, and S22 is 30 mm. That is, the diameter of the diaphragm 153 (the second diaphragm) is larger than the diameter of the diaphragm 113 (the first diaphragm).

[0053] <Reflector 13 and support portion 14>

[0054] The reflector 13 is a concave structure having a paraboloid of revolution or a surface approximate to the paraboloid of revolution on the inner side. That is, at least a part of the inner wall surface 131 of the reflector 13 is a paraboloid of revolution or a surface approximate to the paraboloid of revolution. This paraboloid of revolution has, for example, a shape formed by rotating a parabola around the axis A1 (a specified axis). The entire inner wall surface 131 may also be a paraboloid of revolution or a surface approximate to the paraboloid of revolution, or only a part of the inner wall surface 131 (for example, only the inner wall surface 131 on the bottom 131a side of the reflector 13, only the inner wall surface 131 on the front end portion 131c side) may be a paraboloid of revolution or a surface approximate to the paraboloid of revolution.

[0055] The driver unit 11 is disposed inside the reflector 13. The driver unit 11 is fixed to the inner wall surface 131 of the reflector 13 via the support portion 14. In the present embodiment, one surface 111 of the driver unit 11 disposed inside the reflector 13 faces the open end 130 side (D1 direction side) of the reflector 13, and the other surface 112 faces the bottom 131a side (D2 direction side) of the reflector 13. The driver unit 11 (first driver unit) emits an audio signal AC1 (first audio signal) to the D1 direction side (one side) of the driver unit 11 and emits an audio signal AC2 (second audio signal) to the D2 direction side (the other side) of the driver unit 11. The audio signal AC1 (playing audio signal) emitted from the driver unit 11 is emitted to the outside from the open end 130 on the D1 direction side of the reflector 13. Here, a part of the audio signal AC1 is directly emitted from the driver unit 11 to the D1 direction side of the reflector 13. In addition, at least a part of the other audio signal AC1 is emitted to the D1 direction side from the open end 130 after being reflected by the inner wall surface 131 of the reflector 13. In addition, at least a part of the audio signal AC2 is emitted to the D1 direction side from the open end 130 after being reflected by the inner wall surface 131 of the reflector 13. A user located on the D1 direction side can listen to the audio signal AC1 emitted from the open end 130 of the reflector 13. At this time, through the reflector 13, leakage of the audio signal AC1 to the back surface 132 side of the reflector 13 can be suppressed. In addition, the audio signal AC2 is an anti-phase signal of the audio signal AC1 or an approximate signal of the anti-phase signal. Therefore, at a specified position on the D1 direction side other than the presence of the user (for example, a position behind the user), a part of the audio signal AC1 cancels out a part of the audio signal AC2, suppressing leakage of the audio signal AC1. In addition, it is preferable that the driver unit 11 is disposed on the axis A1. For example, it is preferable that the diaphragm 113 is disposed on the axis A1. More preferably, the center of the diaphragm 113 or the vicinity thereof is disposed on the axis A1. In other words, it is preferable that the diaphragm 113 is disposed at or near the center of the above-mentioned paraboloid of revolution. As a result, the sound pressure of the audio signal AC1 emitted from the open end 130 becomes axisymmetric or substantially axisymmetric with respect to the axis A1. In addition, more preferably, the driver unit 11 is disposed at or near the focus of the paraboloid of revolution. In this case, the directivity of the audio signal AC1 emitted from the open end 130 becomes higher. A detailed description will be given of this. As Figure 6 illustrated, in the X-Y coordinates, let the points on the parabola constituting the paraboloid of revolution be (x, y), let the focus of the paraboloid of revolution be P(0, p), and let the directrix parallel to the X axis passing through the point (0, -p) be L: y = -p. Where p ≠ 0. In this case, the set of points (x, y) that are equidistant from the focus P(0, p) and the directrix L: y = -p satisfies x 2 = 4py. AsFigure 7A As illustrated, when the drive unit 11 is arranged near the focus P(0, p) of the paraboloid of revolution or the focus P(0, p), the center of the traveling direction of the sound signal AC1 emitted from the open end 130 becomes parallel to the Y-axis (axis A1). Therefore, if the drive unit 11 is arranged near the focus P(0, p) of the paraboloid of revolution or the focus P(0, p), the directivity of the sound signal AC1 emitted from the open end 130 becomes higher. On the other hand, as Figure 7B illustrated, when the drive unit 11 is arranged at a position (0, q) deviated from near the focus P(0, p) of the paraboloid of revolution or the focus P(0, p) (p≠q), the center of the traveling direction of the sound signal AC1 emitted from the open end 130 expands outward with respect to the Y-axis. In this case, compared with the case where the drive unit 11 is arranged near the focus P(0, p) of the paraboloid of revolution or the focus P(0, p), the directivity of the sound signal AC1 emitted from the reflector 13 becomes lower.

[0056] The higher the frequencies of the sound signals AC1 and AC2 are, the shorter their wavelengths are, and the higher their linearity is. Therefore, the directivities of the high-frequency components of the sound signals AC1 and AC2 emitted from the open end 130 of the reflector 13 are high, and it is difficult for these high-frequency components to leak to the back surface 132 side of the reflector 13. Here, a part of the sound signal AC2 is reflected by the inner wall surface 131 of the reflector 13 and then emitted from the open end 130 toward the D1 direction side. The sound signal AC2 is an anti-phase signal of the sound signal AC1 or an approximate signal of the anti-phase signal. However, the wavelengths of these high-frequency components are short, and it is difficult for them to cancel each other out. Therefore, on the D1 direction side, the sound pressure of the high-frequency components of the sound signal AC1 can be sufficiently ensured. On the other hand, the directivities of the intermediate-frequency components / low-frequency components of the sound signals AC1 and AC2 emitted from the open end 130 are low, and they are likely to leak to the back surface 132 side. However, the sound signal AC2 is an anti-phase signal of the sound signal AC1 or an approximate signal of the anti-phase signal, and the wavelengths of these low-frequency components are long, and they are likely to cancel each other out. Therefore, even if the low-frequency components of the sound signals AC1 and AC2 leak to the back surface 132 side, the leakage sound can be suppressed by their mutual cancellation. In order to cancel the sound signal AC1 with the sound signal AC2 at a position where leakage sound is desired to be suppressed, ideally, the difference between the transmission distance from one surface 111 of the driver unit 11 to the position where leakage sound is desired to be suppressed and the transmission distance from the other surface 112 of the driver unit 11 to the position where leakage sound is desired to be suppressed is an integer multiple (including the same) of the wavelengths of the sound signals AC1 and AC2. In order to optimize this condition, one or more sound holes 131b (reflector sound holes) are provided in the reflector 13 of the present embodiment. Thereby, the leakage of the intermediate-frequency components / low-frequency components of the sound signals AC1 and AC2 can be suppressed. In addition, the sound hole 131b has the effect of weakening the directivity of the high-frequency components of the sound signals AC1 and AC2. If the sound pressure of the high-frequency components is too high, it may sometimes be felt harsh, but by providing the sound hole 131b, the sound pressure of the high-frequency components of the sound signals AC1 and AC2 emitted toward the D1 direction side can be weakened. In addition, in Figure 2 etc., an example is shown in which four rectangular sound holes 131b are arranged on the reflector 13 in an axisymmetric or substantially axisymmetric manner with respect to the axis A1. However, this does not limit the present invention, and circular, triangular, etc. sound holes 131b can also be provided, and a plurality of sound holes 131b having different shapes and sizes can also be provided, and the sound holes 131b can also be arranged while being biased toward any position. For example, the sound holes 131b can be arranged while being biased toward the direction of the leakage problem of the sound signal AC1. And, as Figure 1 , Figure 4As exemplified in the examples of FIG. 1 and FIG. 2 , it is preferred that the sound hole 131b is arranged on the D2 direction side (the other side) of the driver unit 11 (the first driver unit) or in the vicinity of the D2 direction side (the other side) of the driver unit 11 (the first driver unit). As a result, the acoustic signal AC1 emitted from the D1 direction side of the driver unit 11 is not easily emitted from the sound hole 131b, and the acoustic signal AC2 emitted from the D2 direction side of the driver unit 11 is easily emitted from the sound hole 131b. As a result, the difference in the transmission distances of the acoustic signal AC1 and the acoustic signal AC2 can be easily adjusted by the size, number, and arrangement of the sound holes 131b. In addition, the sound hole 131b is, for example, a sound hole that penetrates the reflector 13, but this does not limit the present invention. As long as the acoustic signal on the inner side of the reflector 13 can be led out to the outside, the sound hole 131b may not be a through hole. Here, in order to simplify the description, the case where the shape of the edge of the open end of the sound hole 131b is a quadrilateral (the case where the open end is a square) is exemplified, but this does not limit the present invention. For example, the shape of the edge of the open end of the sound hole 131b may be other shapes such as a circle, an ellipse, a triangle, etc. In addition, the open end of the sound hole 131b may also be a mesh shape.

[0057] With the above configuration, the acoustic signal AC1 (first acoustic signal) is emitted from the D1 direction side (one side) of the driver unit 11 (first driver unit), and the acoustic signal AC2 (second acoustic signal) is emitted from the D2 direction side (the other side) of the driver unit 11 (first driver unit), so that the attenuation rate η of the acoustic signal AC1 (first acoustic signal) at the position P2 (second position) based on the position P1 (first position) can be reduced to 11 becomes a predetermined value η th Next, 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) is set to 12 becomes a predetermined value ω th Here, position P1 (first position) is a predetermined position where the acoustic signal AC1 (first acoustic signal) reaches. On the other hand, position P2 (second position) is a predetermined position farther from the acoustic signal output device 10 than position P1 (first position). The predetermined value η th is the attenuation rate η of an arbitrary or specified acoustic signal (sound) caused by air transmission at position P2 (second position) relative to position P1 (first position) as a reference. 21 A small value (low value). In addition, the predetermined value ω th is the attenuation η caused by air transmission of an arbitrary or specified acoustic signal (sound) at position P2 (second position) relative to position P1 (first position) 22 That is, the acoustic signal output device 10 is designed so that the attenuation rate η11 is a specific attenuation rate η 21 smaller than a predetermined value η th below, or is designed to be an attenuation amount η 12 is a specific attenuation amount η 22 larger than a predetermined value ω th or more. In addition, the audio signal AC1 is air-transmitted from the position P1 to the position P2, and is attenuated due to this air transmission and the audio signal AC2. The attenuation rate η 11 is the ratio (AMP2(AC1) / AMP1(AC1)) of the magnitude AMP2(AC1) of the audio signal AC1 at the position P2, which is attenuated due to the air transmission and the audio signal AC2, to the magnitude AMP1(AC1) of the audio signal AC1 at the position P1. In addition, the attenuation amount η 12 is the difference (|AMP1(AC1)-AMP2(AC1)|) between the magnitude AMP1(AC1) and the magnitude AMP2(AC1). On the other hand, in the case where the audio signal AC2 is not assumed, any or a specified audio signal AC ar transmitted through the air from the position P1 to the position P2 is attenuated due to the air transmission but not due to the audio signal AC2. The attenuation rate η 21 is the magnitude AMP2(AC ar ) of the audio signal AC at the position P2 ar relative to the magnitude AMP1(AC ar ) of the audio signal AC at the position P1 ar ) (AMP2(AC ar ) / AMP1(AC ar ))), and the position P2 is the position that is attenuated due to the air transmission (not attenuated due to the audio signal AC2). In addition, the attenuation amount η 22 is the difference (|AMP1(AC ar )-AMP2(AC ar )|) between the magnitude AMP1(AC ar ) and the magnitude AMP2(AC ar ). In addition, examples of the magnitude of the audio signal are the sound pressure of the audio signal or the energy of the audio signal, etc. In addition, the "leakage sound component" refers to, for example, a component in the audio signal AC1 emitted from the sound hole 161a that has a high possibility of reaching an area other than the user existing in the D1 direction (for example, a person other than the user existing in the D1 direction). For example, the "leakage sound component" can also be a component transmitted outside the specified area on the D1 direction side of the audio signal AC1, or a component transmitted outside the D1 direction side.

[0058] In addition, as Figure 1 , Figure 4As exemplified above, on the bottom 131a side (D2 direction side) of the reflector 13, a sound hole 131aa (reflector sound hole) connected to the internal space of the housing 16 is provided. The sound hole 131aa is, for example, a sound hole penetrating the reflector 13, but this does not limit the present invention. If the sound signal in the internal space of the housing 16 can be led to the inside of the reflector 13, the sound hole 131aa may not be a through hole. Details of the sound hole 131aa will be described later.

[0059] The material constituting the reflector 13 is not limited, but at least the inner wall surface 131 is preferably made of a material that reflects sound signals. For example, the reflector 13 can be made of a rigid body such as synthetic resin or metal, or an elastic body such as rubber.

[0060] <Housing 16>

[0061] The housing 16 (second housing) is a hollow member having a wall portion on the outside and is disposed outside the reflector 13. The housing 16 of the present embodiment is disposed on the D2 direction side of the reflector 13. A driver unit 15 (second driver unit) is housed inside the housing 16. In this example, the driver unit 15 is fixed at a position away from the wall portion 161 on the D1 direction side of the housing 16 by a certain distance. Thus, a hollow region AR0 is provided between the region AR1 inside the wall portion 161 of the housing 16 in this example and the surface 151 on the D1 direction side of the driver unit 15. In the wall portion of the housing 16, one or more sound holes 161a (third sound holes) are provided to lead the sound signal AC3 (third sound signal) emitted from the driver unit 15 to the inside of the reflector 13 via the above-mentioned sound hole 131aa; one or more sound holes 163a (fourth sound holes) are provided to lead the sound signal AC4 (fourth sound signal) emitted from the driver unit 15 to the outside of the housing 16 and outside the reflector 13. In the example of the present embodiment, a recess 161b is provided on the outside of the wall portion 161 on one side (D1 direction side) of the housing 16, and the outside of the bottom 131a of the reflector 13 is fixed to the recess 161b. The sound hole 161a (third sound hole) is provided in the recess 161b and is connected to the sound hole 131aa (reflector sound hole) of the reflector 13 ( Figure 1 、 Figure 4 ). Thus, the sound signal AC3 emitted to the region AR0 from the driver unit 15 is led to the inside of the reflector 13 through the sound hole 161a and the sound hole 131aa. The sound signal AC3 led to the inside of the reflector 13 is emitted from the open end 130 of the reflector 13 to the D1 direction side. In addition, it is preferable that the center of the sound hole 131aa (reflector sound hole) connected to the sound hole 161a (third sound hole) or the plurality of sound holes 131aa (reflector sound holes) connected to one or more sound holes 161a (third sound holes) is arranged near the axis A1 (axis) or the axis A1 (axis). (For example,Figure 5 ). Thus, the sound pressure of the sound signal AC3 emitted from the open end 130 of the reflector 13 is axisymmetric or substantially axisymmetric with respect to the axis A1. In addition, the sound hole 163a faces the external space on the back surface 132 side of the reflector 13, and the sound signal AC4 that is emitted into the hollow region AR (internal space) of the housing 16 on the D2 direction side of the driver unit 15 is led out to the outside of the reflector 13 through the sound hole 163a. As described above, the sound signal AC4 is an anti-phase signal of the sound signal AC3 or an approximate signal of the anti-phase signal. In addition, the sound signal AC3 is a in-phase signal of the sound signal AC1 or an approximate signal of the in-phase signal, and the sound signal AC4 is a in-phase signal of the sound signal AC2 or an approximate signal of the in-phase signal. Therefore, at least a part of the sound signal AC4 emitted from the sound hole 163a cancels at least a part of the leakage sound component of the sound signals AC1 and AC3 emitted from the open end 130 of the reflector 13. Thus, it is also possible to suppress leakage sound, particularly leakage sound on the low-frequency side (sound signal AC3). In addition, the sound hole 161a and the sound hole 163a are, for example, sound holes penetrating the wall portion of the housing 16, but the present invention is not limited thereto. If the sound signal AC3 can be led into the reflector 13 and the sound signal AC4 can be led out to the outside of the reflector 13, the sound holes 161a and 163a may not be through holes. The shape of the housing 16 is not limited. For example, the shape of the housing 16 is preferably rotationally symmetric (line symmetric) or substantially rotationally symmetric about the axis A1. Thus, it is easy to provide the sound hole 163a so as to reduce the deviation of the sound pressure in each direction of the sound signal AC4 emitted from the housing 16. As a result, it is easy to reduce leakage sound uniformly in each direction. For example, the housing 16 has: a wall portion 161 disposed on one side (D1 direction side) of the driver unit 15; a wall portion 162 disposed on the other side (D2 direction side) of the driver unit 15; and a wall portion 163 surrounding the space ([ Figure 1 , Figure 4 ) sandwiched between the wall portion 161 and the wall portion 162 by the axis A1 passing through the wall portion 161 and the wall portion 162. Here, for simplicity of explanation, an example of a substantially cylindrical shape of the housing 16 having two end faces is shown. However, these are merely examples and do not limit the present invention. For example, the housing 16 may be a substantially dome-shaped shape having a wall portion at the end, a substantially cubic shape that is hollow, or other three-dimensional shapes. In addition, the material constituting the housing 16 is not limited. The housing 16 may be formed of a rigid body such as synthetic resin or metal, or may be formed of an elastic body such as rubber.

[0062] Users in the specified area on the D1 direction side can listen to the sound signals AC1 and AC3 emitted from the open end 130 of the reflector 13. As described above, the sound signal AC2, which is an inverted signal of the sound signal AC1 or an approximate signal of the inverted signal, is emitted from the sound hole 131b. In addition, the sound signal AC4, which is an inverted signal of the sound signal AC3 or an approximate signal of the inverted signal, is emitted from the sound hole 163a. Here, a part of the emitted sound signals AC2 and AC4 cancels a part (leakage sound component) of the sound signals AC1 and AC3 emitted from the open end 130 of the reflector 13. For example, a part of the sound signal AC2 mainly cancels a part of the sound signal AC1, and a part of the sound signal AC4 mainly cancels a part of the sound signal AC3. That is, the sound signal AC1 (first sound signal) is emitted from the D1 direction side (one side) of the driver unit 11 (first driver unit), the sound signal AC2 (second sound signal) is emitted from the D2 direction side (the other side) of the driver unit 11 (first driver unit), the sound signal AC3 (third sound signal) is emitted from the D1 direction side (one side) of the driver unit 15 (second driver unit), and the fourth sound signal is emitted from the D2 direction side (the other side) of the driver unit 15 (second driver unit). Thus, the attenuation rate η of the sound signals AC1 (first sound signal) and the third sound signal (third sound signal) at the position P2 (second location) based on the position P1 (first location) 112 becomes a predetermined value η th Hereinafter, or the attenuation amount η of the sound signals AC1 (first sound signal) and the third sound signal (third sound signal) at the position P2 (second location) based on the position P1 (first location) 122 becomes a predetermined value ω th The above. Here, the position P1 (first location) is a predetermined location where the emitted sound signals AC1 (first sound signal) and the sound signal AC3 (third sound signal) arrive. On the other hand, the position P2 (second location) is a predetermined location farther from the sound signal output device 10 than the position P1 (first location). The predetermined value η th is a value (low value) smaller than the attenuation rate η caused by the air transmission of any or specified sound signal (sound) at the position P2 (second location) based on the position P1 (first location) 21 In addition, the predetermined value ω th is a value larger than the attenuation amount η caused by the air transmission of any or specified sound signal (sound) at the position P2 (second location) based on the position P1 (first location) 22 That is, the sound signal output device 10 of the present embodiment is designed such that the attenuation rate η 112 is smaller than the attenuation rate η21 A small pre-determined value η th Hereinafter, or designed to be the attenuation amount η 122 Is the attenuation amount η 22 A large pre-determined value ω th Above. In addition, the audio signal AC1 and the audio signal AC3 are transmitted through the air from the position P1 to the position P2, and are attenuated due to this air transmission, the audio signal AC2, and the audio signal AC4. The attenuation rate η 112 Is the ratio (AMP2(AC1) / AMP1(AC1)) of the magnitude AMP2(AC1) of the audio signal AC1 at the position P2, which is attenuated due to air transmission and the audio signals AC2 and AC4, to the magnitude AMP1(AC1) of the audio signal AC1 at the position P1, or the ratio (AMP2(AC3) / AMP1(AC3)) of the magnitude AMP2(AC3) of the audio signal AC3 at the position P2, which is attenuated due to air transmission, the audio signals AC2, and the audio signals AC4, to the magnitude AMP1(AC3) of the audio signal AC3 at the position P1. Or, the attenuation rate η 112 Can also be a statistical value (average value, sum value, product value, etc.) of the ratio (AMP2(AC1) / AMP1(AC1)) and the ratio (AMP2(AC3) / AMP1(AC13)). In addition, the attenuation amount η 122 Is the difference (|AMP1(AC1)-AMP2(AC1)|) between the magnitude AMP1(AC1) and the magnitude AMP2(AC1), or the difference (|AMP1(AC3)-AMP2(AC3)|) between the magnitude AMP1(AC3) and the magnitude AMP2(AC3). Or, the attenuation amount η 122 Can also be a statistical value (average value, sum value, product value, etc.) of the difference (|AMP1(AC1)-AMP2(AC1)|) and the difference (|AMP1(AC3)-AMP2(AC3)|). On the other hand, in the case where the audio signals AC2 and AC4 are not assumed, any or specified audio signal AC transmitted through the air from the position P1 to the position P2 ar Is not attenuated due to the audio signals AC2 and AC4 but due to air transmission. The attenuation rate η 21 Is the magnitude AMP2(AC ar ) of the audio signal AC at the position P2, which is attenuated due to air transmission (not attenuated due to the audio signal AC2 ar ) relative to the magnitude AMP1(AC ar ) of the audio signal AC at the position P1 ar ). The ratio (AMP2(AC ar ) / AMP1(AC ar ). In addition, the attenuation amount η22 is the difference (|AMP1(AC ar ) - AMP2(AC ar )|) between the magnitudes of AMP1(AC ar ) and AMP2(AC ar ).

[0063] With the above structure, sound leakage can be suppressed. In particular, the size of the driver unit 11 (first driver unit) is smaller than the size of the driver unit 15 (second driver unit). In addition, the driver unit 11 is disposed inside the reflector 13, and the sound signals AC1 and AC2 emitted from the driver unit 11 are emitted from the open end 130 and the sound hole 131b of the reflector 13. On the other hand, the driver unit 15 is housed inside the housing 16 located outside the reflector 13, and the sound signal AC3 emitted from the driver unit 15 is introduced inside the reflector 13 and then further emitted from the open end 130 of the reflector 13. In contrast, the sound signal AC4 emitted from the driver unit 15 is emitted to the outside of the reflector 13 through the sound hole 163a of the housing 16. Therefore, the difference in the transmission distances of the sound signal AC1 emitted from the D1 direction side of the diaphragm 113 of the driver unit 11 to the position P2 (second location) and the sound signal AC2 (second sound signal) emitted from the D2 direction side (the other side) of the diaphragm 113 to the position P2 (second location) is smaller than the difference in the transmission distances of the sound signal AC3 emitted from the D1 direction side (one side) of the diaphragm 153 of the driver unit 15 to the position P2 (second location) and the sound signal AC4 emitted from the D2 direction side (the other side) of the diaphragm 153 to the position P2 (second location). Here, the smaller the difference in the transmission distances, the larger the phase difference between the anti-phase waves (sound signals AC2 and AC4) and the playback sound (sound signals AC1 and AC3) at the position P2, and the more the sound leakage prevention effect is improved. Therefore, in terms of size and configuration, the sound leakage prevention effect on the driver unit 11 side is higher than that on the driver unit 15 side. On the other hand, the higher the frequency, the more easily it is affected by the difference in the transmission distances. Therefore, there is a tendency that the higher the frequency, the lower the sound leakage prevention effect. Here, the driver unit 11 is responsible for playing the sound signal mainly in the high frequency range, and the driver unit 15 is responsible for playing the sound signal mainly in the low frequency range. Therefore, in terms of frequency, the sound leakage prevention effect on the driver unit 15 side is higher than that on the driver unit 11 side. Due to these characteristics of the sound leakage prevention effect, a sufficient sound leakage prevention effect can be obtained in a wide frequency band. In addition, since the diameter of the diaphragm 153 (second diaphragm) of the driver unit 15 is larger than the diameter of the diaphragm (first diaphragm) of the driver unit 11, the sound pressure of the bass can be made larger on the driver unit 15 side than the sound pressure of the driver unit 11. Thus, it is possible to sufficiently obtain the sound pressure of the low frequency while suppressing the sound leakage.

[0064] <Configuration structure of sound holes 161a and 163a>

[0065] The configuration structure of the sound holes 161a and 163a is illustrated.

[0066] The sound hole 161a (third sound hole) illustrated here is provided in the region AR1 (first region) of the wall portion 161 ( Figure 1 , Figure 4 ), and the wall portion 161 is disposed on one side of the driver unit 15 (the side that emits the audio signal AC3, i.e., the D1 direction side) ( Figure 1 , Figure 4 ). That is, the sound hole 161a opens in the D1 direction (first direction) along the axis A1 and communicates with the sound hole 131aa of the reflector 13. In addition, the sound hole 163a (fourth sound hole) illustrated here is provided in the region AR3 of the wall portion 163 that is adjacent to the region AR between the region AR1 (first region) of the wall portion 161 of the housing 16 and the region AR2 (second region) of the wall portion 162 disposed on the D2 direction side (the other side that emits the audio signal AC4) of the driver unit 15. That is, when the direction between the D1 direction (first direction) and the opposite direction of the D1 direction is set as the D12 direction (second direction) with the center of the housing 16 as a reference ( Figure 4 ), the sound hole 161a (third sound hole) is provided on the D1 direction side (first direction side) of the housing 16, and the sound hole 163a (fourth sound hole) is provided on the D12 direction side (second direction side) of the housing 16. For example, the housing 16 has: a wall portion 161 disposed on one side of the driver unit 15 (D1 direction side); a wall portion 162 disposed on the other side of the driver unit 15 (D2 direction side); and a wall portion 163 (side surface) that surrounds the space sandwiched between the wall portion 161 and the wall portion 162 with the axis A1 along the emission direction (D1 direction) of the audio signal AC3 passing through the wall portion 161 and the wall portion 162 as the center ( Figure 4 ), the sound hole 161a (third sound hole) is provided in the wall portion 161, and the sound hole 163a (fourth sound hole) is provided in the wall portion 163 (side surface). In addition, in this example, it is preferable that no sound hole is provided on the wall portion 162 side of the housing 16. This is because if a sound hole is provided on the wall portion 162 side of the housing 16, the sound pressure level of the audio signal AC4 emitted from the housing 16 exceeds the level required to cancel the leakage sound component of the audio signal AC3, and the excess portion is perceived as leakage sound.

[0067] As Figure 1As exemplified above, the sound hole 161a exemplified here is disposed on or near the axis A1 along the emission direction (D1 direction) of the audio signal AC3. The axis A1 of this example passes through the center or near the center of the region AR1 (first region) of the wall portion 161 on the side (D1 direction side) of the driver unit 15 of the housing 16. For example, the axis A1 is an axis that passes through the central region of the housing 16 and extends in the D1 direction. That is, the sound hole 161a of this example is provided at the central position of the region AR1 of the wall portion 161 of the housing 16. In this example, for simplicity of explanation, an example is shown in which the shape of the edge portion of the open end of the sound hole 161a is a circle (the open end is circular). However, this does not limit the present invention. For example, the shape of the edge portion of the open end of the sound hole 161a may also be other shapes such as an ellipse, a quadrilateral, or a triangle. In addition, the open end of the sound hole 161a may also be a mesh shape. In other words, the open end of the sound hole 161a may be composed of a plurality of holes. In addition, in this example, for simplicity of explanation, an example is shown in which four sound holes 161a are provided in the region AR1 (first region) of the wall portion 161 of the housing 16. However, this does not limit the present invention. For example, one or more sound holes 161a may be provided in the region AR1 (first region) of the wall portion 161 of the housing 16, or other numbers of sound holes 161a may be provided.

[0068] The sound hole 163a (fourth sound hole) is preferably configured, for example, in consideration of the following viewpoints.

[0069] (1) Viewpoint of position: The sound hole 163a is arranged so that the transmission path of the audio signal AC4 emitted from the sound hole 163a overlaps with the transmission path of the leakage component of the audio signal AC3 to be canceled.

[0070] (2) Viewpoint of area: Depending on the opening area of the sound hole 163a, the transmission area of the audio signal AC4 emitted from the sound hole 163a and the frequency characteristics of the housing 16 are different. In addition, the frequency characteristics of the housing 16 affect the frequency characteristics of the audio signal AC4 emitted from the sound hole 163a, that is, the amplitude at each frequency. Considering the transmission area and frequency characteristics of the audio signal AC4 emitted from such a sound hole 163a, the opening area of the sound hole 163a is determined so that in the region where the leakage component is to be canceled, the leakage component is canceled by the audio signal AC4 emitted from the sound hole 163a.

[0071] From the above viewpoints, for example, the sound hole 163a (fourth sound hole) is preferably configured as follows.

[0072] For example, as Figure 3 、 Figure 5As exemplified, it is preferable to provide a plurality of sound holes 163a (fourth sound holes) along a circumference (circle) C1 centered on an axis A1 along the emission direction of an acoustic signal AC3 (first acoustic signal). When a plurality of sound holes 163a are provided along the circumference C1, the acoustic signal AC4 is emitted radially outward from the sound holes 163a (radially centered on the axis A1). Here, the leaking component of the acoustic signal AC3 is also emitted radially outward from the sound holes 161a (radially centered on the axis A1). Therefore, by providing a plurality of sound holes 163a along the circumference C1, the leaking component of the acoustic signal AC3 can be appropriately canceled by the acoustic signal AC4. Here, for simplicity of explanation, an example in which a plurality of sound holes 163a are provided on the circumference C1 is shown. However, as long as a plurality of sound holes 163a are provided along the circumference C1, it is not necessary to strictly arrange all the sound holes 163a on the circumference C1.

[0073] In addition, preferably, when the circumference C1 is equally divided into a plurality of unit arc regions, the total opening area of the sound holes 163a (fourth sound holes) provided along a first arc region, which is any one of the unit arc regions, is the same as or substantially the same as the total opening area of the sound holes 163a (fourth sound holes) provided along a second arc region, which is any one of the unit arc regions other than the first arc region. For example, as Figure 5As exemplified, when the circumference C1 is equally divided into four unit arc regions C1-1, …, C1-4, the sum of the opening areas of the sound holes 163a (fourth sound holes) provided along the first arc region (e.g., the unit arc region C1-1) among the unit arc regions C1-1, …, C1-4 is the same as or substantially the same as the sum of the opening areas of the sound holes 163a (fourth sound holes) provided along the second arc region (e.g., the unit arc region C1-2) among the unit arc regions other than the first arc region. In addition, here, for simplicity of explanation, an example in which the circumference C1 is equally divided into four unit arc regions C1-1, …, C1-4 is shown, but this does not limit the present invention. Further, “α1 is substantially the same as α2” means that the difference between α1 and α2 is β% or less of α1. Examples of β% are 3%, 5%, 10%, etc. Thus, the sound pressure distribution of the sound signal AC4 emitted from the sound holes 163a provided along the first arc region and the sound pressure distribution of the sound signal AC4 emitted from the sound holes 163a provided along the second arc region are point-symmetrical or substantially point-symmetrical with respect to the axis A1. Preferably, the sum of the opening areas of the sound holes 163a (fourth sound holes) provided along each unit arc region is all the same or substantially the same. Thus, the sound pressure distribution of the sound signal AC4 emitted from the sound holes 163a becomes point-symmetrical or substantially point-symmetrical with respect to the axis A1. Thus, the leakage sound component of the sound signal AC3 can be more appropriately canceled by the sound signal AC4.

[0074] More preferably, the plurality of sound holes 163a are provided along the circumference C1 in the same shape, the same size, and the same interval. When the plurality of sound holes 163a are provided along the circumference C1 in the same shape, the same size, and the same interval, the leakage sound component of the sound signal AC3 can be more appropriately canceled by the sound signal AC4. However, this does not limit the present invention.

[0075] Here, for simplicity of explanation, an example in which the shape of the edge portion of the open end of the sound hole 163a is a quadrilateral (the open end is square) is shown, but this does not limit the present invention. For example, the shape of the edge portion of the open end of the sound hole 163a may also be other shapes such as a circle, an ellipse, a triangle, etc. In addition, the open end of the sound hole 163a may also be in a mesh shape. In other words, the open end of the sound hole 163a may be composed of a plurality of holes. In addition, the number of the sound holes 163a is not limited, and a single sound hole 163a may be provided in the region AR3 of the wall portion 163 of the housing 16, or a plurality of sound holes 163a may be provided.

[0076] <Cut-off frequency of the reflector 13 in which the driver unit 11 is disposed>

[0077] The cutoff frequency of the reflector 13 equipped with the driver unit 11 is studied. In Figure 8A a horn speaker in which a horn 13' is installed in the driver unit 11' is illustrated. Here, the opening area of the mouth portion of the horn 13' is set as S1', the opening area of the throat portion of the horn 13' is set as S2', and the length of the horn 13' is set as S3'. The driver unit 11' is installed on the mouth portion of the horn 13'. The cutoff frequency f of this horn speaker c is as shown in the following formula (1).

[0078] [Mathematical formula 1]

[0079]

[0080] Here, m represents the expansion coefficient, and c represents the speed of sound. In addition, the sound pressure of the sound signal emitted from the mouth portion of the horn speaker drops sharply when it exceeds the cutoff frequency f c . That is, the cutoff frequency f c represents the frequency characteristics of the sound signal that can be output from the horn speaker. Here, it is known that the following relationship of formula (2) holds.

[0081] [Mathematical formula 2]

[0082]

[0083] When this formula (2) is transformed, the following formula (3) is obtained.

[0084] [Mathematical formula 3]

[0085]

[0086] When formula (3) is further transformed, the expansion coefficient m can be approximated as in the following formula (4).

[0087] [Mathematical formula 4]

[0088]

[0089] The reflector 13 of this embodiment is different from the horn, but the cutoff frequency of the reflector 13 equipped with the driver unit 11 is considered to represent a characteristic close to it. In Figure 8BThe reflector 13 of the driver unit 11 of the present embodiment is illustrated. Here, the opening area S1 of the open end 130 of the reflector 13 is regarded as the opening area S1' of the mouth portion of the horn, the area S2 of the surface 111 of the driver unit 11 is regarded as the opening area S2' of the throat portion of the horn, and the length S3 from the surface 111 of the driver unit 11 to the open end 130 of the reflector 13 is regarded as the length S3' of the horn. Then, according to Equation (1) and Equation (4), the cut-off frequency f of the reflector 13 in which the driver unit 11 is configured c can be approximated as the following Equation (5).

[0090] [Equation 5]

[0091]

[0092] That is, the reflector 13 in which the driver unit 11 is configured can be regarded as a speaker having a cut-off frequency f represented by Equation (5). c

[0093] <Reproduction device 100 and signal separation device 101>

[0094] As Figure 9A illustrated, the output signal output from the playback device 100 is input to the signal separation device 101. The signal separation device 101 separates the input output signal into a high-frequency band signal on the high-frequency side and a low-frequency band signal on the low-frequency side. In Figure 9B the example, the output signal is branched into two, and the branched output signals are respectively input to the high-pass filter 101a and the low-pass filter 101b. The high-pass filter 101a attenuates the low-frequency side of the input output signal to obtain and output a high-frequency band signal. The low-pass filter 101b attenuates the high-frequency side of the input output signal to obtain and output a low-frequency band signal. The high-frequency band signal is input to the driver unit 11 of the audio signal output device 10, and the driver unit 11 emits the audio signal AC1 to the D1 direction side and the audio signal AC2 to the D2 direction side. The low-frequency band signal is input to the driver unit 15 of the audio signal output device 10, and the driver unit 15 emits the audio signal AC3 to the D1 direction side and the audio signal AC4 to the D2 direction side.

[0095] As Figure 9B illustrated, in the present embodiment, the cross frequency is set to f cross , and the driver unit 11 emits high-frequency band audio signals AC1 and AC2 having sufficient sound pressure at a frequency equal to or higher than the cross frequency f cross , and the driver unit 15 emits high-frequency band audio signals AC1 and AC2 having sufficient sound pressure at a frequency equal to or higher than the cross frequency f cross ​The low-pass filter 101b emits low-frequency acoustic signals AC3 and AC4 with sufficient sound pressure at the frequencies below the crossover frequency f. cross The high-pass filter 101a outputs a signal in the low-frequency band with sufficient sound pressure at the frequency below f. cross The frequency above this level has a high-frequency signal with sufficient sound pressure. cross It is preferably set to be lower than the cutoff frequency f of the speaker composed of the driver unit 11 and the reflector 13 shown in equation (5). c That is, the crossover frequency f between the high frequency band and the low frequency band is preferably cross Compared with the cutoff frequency f shown in formula (5), c For example, the crossover frequency f cross An example is 1000 [Hz] or its vicinity, and the cut-off frequency f c is a frequency higher than 1000 [Hz]. Thus, sufficient sound pressure can be obtained in the high frequency band. In addition, the crossover frequency f is determined cross and the cutoff frequency f c This is so that a full-band signal having a desired frequency characteristic can be obtained at the listening point of the user located on the D1 direction side.

[0096] <Experimental Results>

[0097] The experimental results are shown in Figure 10A , Figure 10B , Figure 11A , Figure 11B as well as Figure 12 Graphs (radar graphs) showing the sound pressures of the frequencies 805 Hz, 1000 Hz, 1995 Hz, 3981 Hz, and 7943 Hz of the sound signal observed around the sound signal output device 10 of the present embodiment are shown. 0 [deg] indicates the D1 direction, 180 [deg] indicates the D2 direction, and each line indicates the sound pressure level at a distance of 100 mm, 200 mm, 300 mm, and 400 mm in each direction from the sound signal output device 10. In these graphs, the sound pressure level is lower as it is closer to the center, and the sound pressure level is higher as it is closer to the outside.

[0098] exist Figures 13A to 15The figure shows graphs representing the frequency characteristics of the sound signals observed around the sound signal output device 10 of the present embodiment. The horizontal axis of these graphs represents the frequency [Hz], and the vertical axis represents the sound pressure level [dB]. Each line represents the sound pressure level [dB] with respect to each direction [deg] and each relative position [mm] of the sound signal output device 10. In the examples of these graphs, "aaa deg_bbb mm_cl" indicates the sound pressure level [dB] observed at a position where the direction with respect to the sound signal output device 10 is aaa [deg] and the relative position is bb [mm].

[0099] Thus, in the sound signal output device 10 of the present embodiment, in a wide frequency band, sufficient sound pressure is ensured in the specified area on the D1 direction side, and sound leakage to positions other than that can be sufficiently suppressed. In particular, due to the directivity of the reflector 13, even in the high-frequency region exceeding 1000 Hz, sufficient sound pressure can be ensured in the specified area on the D1 direction side, and sound leakage to positions other than that can be sufficiently suppressed. Thus, in the present embodiment, in a wide frequency band including the high-frequency band, sound leakage to the surroundings can be suppressed.

[0100] [Modification Example 1 of the First Embodiment]

[0101] Hereinafter, the description will focus on the differences from the matters described so far, and the description of the matters already described will be simplified. As described above, a single sound hole 161a may be provided in the region AR1 of the wall portion 161 of the housing 16, or a plurality of sound holes 161a may be provided. A single sound hole 131aa connected to the sound hole 161a may be provided on the bottom 131a side of the reflector 13, or a plurality of sound holes 131aa may be provided. In addition, the reflector 13 may be biased to an eccentric position (a position on the axis A12 parallel to the axis A1 deviated from the axis A1) deviated from the center (central position) of the housing 16 (hereinafter, simply referred to as "eccentric position"). For example, as Figure 16 illustrated, the centers of the plurality of sound holes 161a and the sound hole 131aa are arranged on the axis A1, and the reflector 13 is offset on the axis A12. Or, as Figure 17 illustrated, one sound hole 161a and the sound hole 131aa are arranged on the axis A1, and the reflector 13 is offset on the axis A12. In other words, the reflector 13 may be arranged to be biased with respect to the housing 16, one sound hole 161a, and the sound hole 131a.

[0102] When the reflector 13 is arranged to be biased with respect to the housing 16, one sound hole 161a, and the sound hole 131aa, the distribution and opening area of the sound hole 16a may also be biased accordingly. In Figure 16In the example, the number of sound holes 163a provided along the unit arc regions C1-3 and C1-4 far from the axis A12 is smaller than the number of sound holes 163a provided along the unit arc regions C1-1 and C1-2 close to the axis A12. In Figure 17 In the example, the opening areas of the sound holes 163a provided along the unit arc regions C1-3 and C1-4 far from the axis A12 are smaller than the opening areas of the sound holes 163a provided along the unit arc regions C1-1 and C1-2 close to the axis A12. That is, in the case where the circumference C1 is equally divided into a plurality of unit arc regions, the total opening area of the sound holes 163a (second sound holes) provided along any one of the unit arc regions, for example, the first arc regions (C1-3, C1-4), is smaller than the total opening area of the sound holes 163a provided along any one of the unit arc regions, for example, the second arc regions (C1-1, C-2), closer to the axis A12 than the first arc regions. In the case where the reflector 13 is disposed at an eccentric position, the distribution of the sound signal AC3 emitted from the open end 130 of the reflector 13 to the outside also biases toward the eccentric position. Here, by also biasing the distribution and the opening area of the sound holes 163a toward the eccentric position, the distribution of the sound signal AC4 emitted from the sound holes 163a to the outside can also bias toward the eccentric position. Thus, the leakage component of the sound signal AC3 can be sufficiently canceled by the emitted sound signal AC4.

[0103] [Modification Example 2 of the First Embodiment]

[0104] As Figures 18 to 21 illustrated, in the first embodiment or its modification example 1, the driver unit 11 (first driver unit) may also be housed inside a different housing 12 (first housing) from the housing 16 (second housing), and thus the housing 12 housing the driver unit 11 inside may also be disposed inside the reflector 13.

[0105] <housing 12>

[0106] The housing 12 is a hollow member having a wall portion on the outside, and sound holes 121a and 123a are provided in the wall portion, and the driver unit 11 is housed inside. For example, the driver unit 11 is fixed to the end portion on the D1 direction side inside the housing 12. The shape of the housing 12 is not limited either. For example, the shape of the housing 12 is preferably rotationally symmetric (line symmetric) or substantially rotationally symmetric about the axis A1. Thereby, it is easy to provide the sound hole 123a so that the deviation of the direction of each energy of the sound signal emitted from the housing 12 becomes smaller. For example, the housing 12 has: a wall portion 121 disposed on one side (D1 direction side) of the driver unit 11, that is, a first end face; a wall portion 122 disposed on the other side (D2 direction side) of the driver unit 11, that is, a second end face; and a wall portion 123 disposed around the space sandwiched by the first end face and the second end face with the axis A1 passing through the first end face and the second end face as the center, that is, a side face. Here, for the sake of simplicity of explanation, an example in which the housing 12 has a substantially cylindrical shape with double end faces is shown. However, these are only examples and do not limit the present invention. For example, the housing 12 may be a substantially dome shape having a wall portion at the end, may be a substantially cubic shape that is hollow, or may be other three-dimensional shapes. In addition, the material constituting the housing 12 is not limited either. 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.

[0107] <Sound holes 121a and 123a>

[0108] As described above, the following are provided in the wall portion of the housing 12: a sound hole 121a (first sound hole) that leads the sound signal AC1 (first sound signal) emitted from the driver unit 11 to the outside (inside the reflector 13); and a sound hole 123a (second sound hole) that leads the sound signal AC2 (second sound signal) emitted from the driver unit 11 to the outside (inside the reflector 13). The sound hole 121a and the sound hole 123a are, for example, through holes that penetrate the wall portion of the housing 12, but this does not limit the present invention. As long as the sound signals AC1 and AC2 can be led to the outside (inside the reflector 13) respectively, the sound holes 121a and 123a may not be through holes.

[0109] An example of the arrangement structure of the sound holes 121a and 123a is illustrated.

[0110] The sound hole 121a (first sound hole) exemplified here is provided in the region AR1 (first region) of the wall portion 121 ( Figure 18 , Figure 19 , Figure 20A , Figure 20B , Figure 21 ), and the wall portion 121 is disposed on one side of the driver unit 11 (the side that emits the sound signal AC1, that is, the D1 direction side) ( Figure 18 , Figure 19, Figure 20A , Figure 20B , Figure 21 )。That is, the sound hole 121a opens in the D1 direction (first direction) along the axis A1. In addition, the sound hole 123a (second sound hole) illustrated here is provided in the region AR3' of the wall portion 123 that is in contact with the region AR' between the region AR1' of the wall portion 121 of the housing 12 and the region AR2' of the wall portion 122 disposed on the D2 direction side (the other side where the sound signal AC2 is emitted) of the drive unit 11. That is, when the direction between the D1 direction (first direction) and the opposite direction of the D1 direction is set as the D12' direction (second direction) with the center of the housing 12 as a reference ( Figure 21 B), 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, the housing 12 has: a wall portion 121 disposed on one side (D1 direction side) of the drive unit 11; a wall portion 122 disposed on the other side (D2 direction side) of the drive unit 11; and a wall portion 123 (side surface) that surrounds the space sandwiched between the wall portion 121 and the wall portion 122 with the axis A1 along the emission direction (D1 direction) of the sound signal AC1 passing through the wall portion 121 and the wall portion 122 as the center ( Figure 18 ), in this case, the sound hole 121a (first sound hole) is provided on the wall portion 121, and the sound hole 123a (second sound hole) is provided on the wall portion 123 (side surface).

[0111] As Figure 18 illustrated in A and the like, the sound hole 121a illustrated here is disposed on or near the axis A1 along the emission direction (D1 direction) of the sound signal AC1. That is, the sound hole 121a in this example is provided at the central position of the region AR1 of the wall portion 121 of the housing 12. In this example, for the sake of simplicity of explanation, an example in which the shape of the edge portion of the open end of the sound hole 121a is a circle (the open end is circular) is shown. However, this does not limit the present invention. For example, the shape of the edge portion of the open end of the sound hole 121a can be other shapes such as an ellipse, a quadrilateral, a triangle, etc. In addition, the open end of the sound hole 121a can also be in a mesh shape. In other words, the open end of the sound hole 121a can also be composed of a plurality of holes. In addition, in this example, for the sake of simplicity of explanation, an example in which one sound hole 121a is provided in the region AR1 (first region) of the wall portion 121 of the housing 12 is shown. However, this does not limit the present invention. For example, two or more sound holes 121a can also be provided in the region AR1 (first region) of the wall portion 121 of the housing 12.

[0112] Preferably, a plurality of sound holes 123a (second sound holes) are provided along a circumference (circle) C1 centered on an axis A1 along the emission direction of the sound signal AC1 (first sound signal). Here, for simplicity of explanation, an example in which a plurality of sound holes 123a are provided on the circumference C1 is shown. However, as long as the plurality of sound holes 123a are provided along the circumference C1, it is not necessary to strictly arrange all the sound holes 123a on the circumference C1.

[0113] In addition, preferably, in the case where 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 any one of the unit arc regions, i.e., the first arc region, is the same as or substantially the same as the sum of the opening areas of the sound holes 123a (second sound holes) provided along any one of the unit arc regions other than the first arc region, i.e., the second arc region.

[0114] More preferably, the plurality of sound holes 123a are provided along the circumference C1 with the same shape, the same size, and the same interval. When the plurality of sound holes 123a are provided along the circumference C1 with the same shape, the same size, and the same interval, the leakage component of the sound signal AC1 can be more appropriately canceled by the sound signal AC2. However, this does not limit the present invention.

[0115] Here, for simplicity of explanation, an example in which the shape of the edge portion of the open end of the sound hole 123a is a quadrilateral (the open end is square) is illustrated, but this does not limit the present invention. For example, the shape of the edge portion of the open end of the sound hole 123a may also be other shapes such as a circle, an ellipse, or a triangle. And the open end of the sound hole 123a may be mesh-shaped. In other words, the open end of the sound hole 123a may also be composed of a plurality of holes. In addition, the number of the sound holes 123a is not limited, and a single sound hole 123a may be provided in the region AR3 of the wall portion 123 of the housing 12, or a plurality of sound holes 123a may be provided.

[0116] The housing 12 is fixed to the inner wall surface 131 of the reflector 13 via the support portion 14. In the present embodiment, the sound hole 121a side of the housing 12 disposed inside the reflector 13 faces the open end 130 side (D1 direction side) of the reflector 13, and the other wall portion 122 faces the bottom 131a side (D2 direction side) of the reflector 13. Preferably, at least a part of the sound holes 123a of the housing 12 are provided at positions opposite to the sound holes 131b of the reflector 13.

[0117] [Modification Example 3 of the First Embodiment]

[0118] As Figure 22A and Figure 22BAs illustrated, in the first embodiment and its modified examples 1 and 2, the housing 16 and the driver unit 15 (second driver unit) may also be omitted. In this case, the sound hole 131aa may also be omitted.

[0119] [Second Embodiment]

[0120] In the first embodiment and its modified examples, instead of the sound hole 131b, or in addition to the sound hole 131b, a cutout portion (slit portion) 231b that opens the inside of the reflector 13 to the outside may be provided in a part on the open end 130 side of the reflector 13. As described above, the sound signals AC1 and AC2 are emitted from the open end 130 of the reflector 13. Here, the sound signal AC2 is an inverted signal of the sound signal AC1 or an approximate signal of the inverted signal. Therefore, at a specified position P22 on the D1 direction side other than the position P21 where the user is present, a part of the sound signal AC1 cancels out a part of the sound signal AC2, thereby suppressing the leakage of the sound signal AC1 at the position P22. However, in the high-frequency components of the sound signals AC1 and AC2, they are difficult to cancel out, and at the position P22, on the contrary, the sound signal AC2 emphasizes the sound signal AC1, sometimes contributing to sound leakage. In response to this, by providing the cutout portion 231b in a part on the open end 130 side of the reflector 13, the sound leakage at the position P22 can be suppressed. By increasing the size of the cutout portion 231b, the sound pressure level of the sound signal AC2 at the position P22 can be reduced. Therefore, it is only necessary to design the size of the cutout portion 231b so that the sound pressure of the sound signal AC2 (second sound signal) at the specified position P22 in the direction of the open end 130 of the reflector 13 becomes below a specified level. For example, it is only necessary to design the size of the cutout portion 231b so that the sound pressure of the sound signal AC2 (second sound signal) at the position P22 above a specified frequency becomes below a specified level. The cutout portion 231b is exemplified below.

[0121] <Example 1 of the cutout portion 231b (cutout portion 231b-SW)>

[0122] Figure 23 and Figure 24 The illustrated sound signal output device 20 provided a horizontally long cutout portion 231b-SW that opens the inside of the reflector 13 to the outside in a part on the open end 130 side of the reflector 13 instead of the sound hole 131b. That is, the shape of the cutout portion 231b-SW in this example is longer in the D4 direction orthogonal to the D1-D2 direction.

[0123] <Example 2 of the cutout portion 231b (cutout portion 231b-LW)>

[0124] As Figure 25The illustrated audio signal output device 20 is provided with a large vertical and horizontal (lengthwise and crosswise) cutout portion 231b-LW that opens the inside of the reflector 13 to the outside on a part of the open end 130 side of the reflector 13, instead of the sound hole 131b. That is, the length of the cutout portion 231b-LW in the D1-D2 direction is the same as that of Figure 23 the cutout portion 231b-SW in the D1-D2 direction, but the length of the cutout portion 231b-LW in the D4 direction is longer than the length of the cutout portion 231b-SW in the D4 direction.

[0125] <Example 3 of the cutout portion 231b (cutout portion 231b-LN)>

[0126] Figure 26 The illustrated audio signal output device 20 is provided with a longitudinally long cutout portion 231b-LN that opens the inside of the reflector 13 to the outside on a part of the open end 130 side of the reflector 13, instead of the sound hole 131b. That is, the length of the cutout portion 231b-LN in the D1-D2 direction of the shape is the same as that of Figure 25 the cutout portion 231b-LW in the D1-D2 direction, but the length of the cutout portion 231b-LN in the D4 direction is shorter than the length of the cutout portion 231b-LW in the D4 direction.

[0127] <Experimental results>

[0128] The experimental results are shown in FIGS. 27 and 28. The vertical axis represents the sound pressure level [dB], and the horizontal axis represents the frequency [Hz]. "L25-aaaaa_bbb_mm.open SPL c°" in the embodiment represents the sound pressure observed on the outside of the audio signal output device 20 on the D3 direction side (the cutout portion 231b side) ( Figure 24 ). On the other hand, "L25-aaaaa_bbb mm.close SPL c°" represents the sound pressure observed on the outside of the audio signal output device 20 on the D4 direction side (the side where the cutout portion 231b is not provided). The line with "L25-aaaaa" being "L25-61065" represents the measurement result of the audio signal output device 20 provided with the cutout portion 231b-SW ( Figure 24 ). The line with "L25-aaaaa" being "L25-61063" represents the measurement result of the audio signal output device 20 provided with the cutout portion 231b-LW ( Figure 25 ). The line with "L25-aaaaa" being "L25-61064" represents the measurement result of the audio signal output device 20 provided with the cutout portion 231b-LN ( Figure 26)。"bbb mm" represents the distance from the audio signal output device 20 to the measurement position, and "c°" represents the direction of the measurement position relative to the audio signal output device 20. "c°" being 0° means the direction of the measurement position relative to the audio signal output device 20 is in the 1 direction. "c°" being 90° means the direction of the measurement position relative to the audio signal output device 20 is the direction orthogonal to the D1 - D2 direction. "c°" being 180° means the direction of the measurement position relative to the audio signal output device 20 is the D2 direction.

[0129] As described above, it can be seen that the leakage sound can be adjusted according to the size and shape of the cutout portion 231b.

[0130] In addition to the above sound holes 131b, a longitudinal cutout portion 231b - LN that opens the inside of the reflector 13 to the outside can also be provided in a part on the open end 130 side of the reflector 13.

[0131] [Third Embodiment]

[0132] In the first embodiment, its modified examples 1 and 2, and the second embodiment, a part of the reflector 13 can also be appropriated as the diaphragm of the driver unit (second driver unit). As a result, the overall size can be miniaturized. A specific example is shown below.

[0133] Figure 29The illustrated audio signal output device 30 includes: a concave reflector 13 having a rotating parabolic surface or a surface approximate to the rotating parabolic surface on the inner side; driver units 11 and 35 (speaker driver units, drivers) that convert an output signal output from a playback device into an audio signal and output it; a housing 36 that houses the driver unit 35 inside; and a support portion 14 that is used to dispose the driver unit 11 inside the reflector 13. However, the reflector 13 is disposed on the side of the wall portion 361 in the D1 direction of the housing 36, and a bottom portion 131a (a part) of the reflector 13 also functions as a diaphragm 353 of the driver unit 35. That is, the driver unit 35 vibrates through the bottom portion 131a of the reflector 13, i.e., the diaphragm 353, and emits an audio signal AC3 (third audio signal) from a surface 353a on the D1 direction side (one side) toward the D1 direction side (one side), and emits an audio signal AC4 (fourth audio signal) from the other surface 353b toward the D2 direction side (the other side) through this vibration. Thereby, the size of the audio signal output device 30 in the D1-D2 direction can be miniaturized. Preferably, at least a part of the inner wall surface 131 of the reflector 13 is a rotating parabolic surface or a surface approximate to the rotating parabolic surface, and the rotating parabolic surface has a shape obtained by rotating a parabola around an axis A1 (a specified axis), and the diaphragm 353 is a part of the bottom portion 131a of the reflector 13 disposed on or near the axis A1. Thus, the sound pressure of the audio signal AC3 emitted from the open end 130 of the reflector 13 is axisymmetric or substantially axisymmetric with respect to the axis A1. Additionally, preferably, one or more sound holes 131b (reflector sound holes) are provided at positions of the reflector 13 other than the diaphragm 353. Thereby, high sound pressure audio signals AC3 and AC4 can be emitted from the diaphragm 353.

[0134] In addition, Figure 29 An example in which the driver unit 11 is not housed in the housing 12 is shown. However, the driver unit 11 (first driver unit) may also be housed inside a housing 12 (first housing) different from the housing 36 (second housing), and the housing 12 that houses the driver unit 11 inside is disposed inside the reflector 13 (refer to Modification Example 2 of the first embodiment).

[0135] [Other Modification Examples]

[0136] Furthermore, the present invention is not limited to the above-described embodiments. For example, in the above-described first embodiment, second embodiment, and their modification examples, an example in which the bottom portion 131a side of the reflector 13 is fixed to the wall portion 161 of the housing 16 is shown, but the bottom portion 131a side of the reflector 13 may also be integrated with the wall portion 161 of the housing 16.

[0137] In addition, the actuator unit 11 is preferably arranged at the focus or near the focus of the rotation parabola of the reflector 13 , but the actuator unit 11 may be arranged at other positions. For example, the actuator unit 11 may be mounted on the bottom 131 a side of the reflector 13 .

[0138] In addition, the reflector 13 may be in a horn shape or other shapes.

[0139] In the above-mentioned embodiment and its modification, it is also possible to Figure 9A The high-pass filter 101a is omitted in the illustrated signal separation device 101. The sound signals AC1 and AC2 emitted from the driver unit 11 are easily canceled out by mutual interference in the mid-low frequency band, so the sound pressure level on the mid-low frequency side generated by the sound signals AC1 and AC2 at the observation point is reduced. On the other hand, since the sound signals AC1 and AC2 are not fully canceled out on the high frequency side, the sound pressure level on the high frequency side of the sound signals AC1 and AC2 at the observation point is high. This feature plays a role equivalent to that of a high-pass filter. Therefore, even if the high-pass filter 101a is omitted from the signal separation device 101, the sound pressure level generated by the sound signals AC1 and AC2 observed at the observation point is suppressed on the mid-low frequency side, and is not suppressed that much on the high frequency band side ( Figure 30B As described above, this effect is particularly significant when the driver unit 11 is accommodated in the housing 12 provided with the sound holes 121a and 123a (for example, variant 2 of the first embodiment). Therefore, even if the high-pass filter 101a is omitted, the effect on the characteristics is small, especially when the driver unit 11 is accommodated in the housing 12 provided with the sound holes 121a and 123a.

[0140] In the case of such a structure, the output signal output from the playback device 100 is input to the signal separation device 101, and the signal separation device 101 branches the input output signal into two. The branched output signals are respectively input to the driver unit 11 and the low-pass filter 101b. The driver unit 11 releases the sound signal AC1 to the D1 direction side and releases the sound signal AC2 to the D2 direction side based on the input output signal. The low-pass filter 101b attenuates the high-frequency side of the input output signal to obtain a low-frequency band signal and outputs it. The low-frequency band signal is input from the sound signal output device 10 to any one of the driver units 15 or 35 of 30, and the driver unit 15 or 35 releases the sound signal AC3 to the D1 direction side and releases the sound signal AC4 to the D2 direction side.

[0141] Description of Reference Numerals

[0142] 10, 20, 30 audio signal output devices; 11, 15, 35 driver units; 12, 16, 36 housings; 13 reflectors; 113, 153, 353 diaphragms; 130 open ends; 231b cutout portions; 101a high-pass filters; 101b low-pass filters; 131a bottoms; 131b, 161a, 163a sound holes.

Claims

1. An audio signal output device having: A concave reflector having a paraboloid of revolution or a surface approximating a paraboloid of revolution on the inner side; and A first driver unit disposed inside the reflector, At a part on the open end side of the reflector, a cutout portion is provided that opens the inside of the reflector to the outside, Regarding the audio signal emitted from the first driver unit to one side as a first audio signal and the audio signal emitted from the first driver unit to the other side as a second audio signal, The audio signal output device is designed such that, when the first audio signal is emitted from one side of the first driver unit and the second audio signal is emitted from the other side of the first driver unit, the attenuation rate of the first audio signal at a second location that is farther from the audio signal output device than the first location, with the first location where the first audio signal arrives as a reference, becomes less than a predetermined value that is the attenuation rate caused by air transmission of the audio signal at the second location with the first location as a reference, or The audio signal output device is designed such that the attenuation amount of the first audio signal at the second location with the first location as a reference becomes greater than a predetermined value that is the attenuation amount caused by air transmission of the audio signal at the second location with the first location as a reference.

2. The audio signal output device according to claim 1, wherein The size of the cutout portion is designed such that the sound pressure of the second audio signal at a specified position in the open end direction of the reflector becomes below a specified level.

3. The audio signal output device according to claim 1, wherein The first driver unit is disposed at or near the focus of the paraboloid of revolution.

4. The audio signal output device according to claim 1, wherein The paraboloid of revolution has a shape formed by rotating a parabola around a specified axis, The first driver unit emits the first audio signal along the axis on one side of the first driver unit and emits the second audio signal along the axis on the other side of the first driver unit, One or more reflector sound holes are provided in the reflector.

5. The audio signal output device according to claim 4, wherein The reflector sound holes are disposed on the other side of the first driver unit or near the other side of the first driver unit.

6. The audio signal output device according to any one of claims 1 to 5, wherein, It further has: A second driver unit; And A second housing that houses the second driver unit inside, The second housing is disposed outside the reflector, Regarding the audio signal emitted from the second driver unit to one side as a third audio signal and the audio signal emitted from the second driver unit to the other side as a fourth audio signal, One or more third sound holes for guiding the third audio signal to the inside of the reflector and one or more fourth sound holes for guiding the fourth audio signal to the outside of the reflector are provided in the wall portion of the second housing, The sound signal output device is designed such that, when the first sound signal is emitted from one side of the first driver unit, the second sound signal is emitted from the other side of the first driver unit, the third sound signal is emitted from one side of the second driver unit, and the fourth sound signal is emitted from the other side of the second driver unit, the attenuation rates of the first sound signal and the third sound signal at the second location with respect to the first location are less than a predetermined value that is less than the attenuation rate caused by air transmission of the sound signal at the second location with respect to the first location, or the sound signal output device is designed such that the attenuation amounts of the first sound signal and the third sound signal at the second location with respect to the first location are greater than or equal to a predetermined value that is the attenuation amount caused by air transmission of the sound signal at the second location with respect to the first location.

7. The sound signal output device according to claim 6, wherein the frequency band for playing the sound signal is divided into a high-frequency band and a low-frequency band, the first driver unit emits the sound signal on the high-frequency band side of the played sound signal, the second driver unit emits the sound signal on the low-frequency band side of the played sound signal.

8. According to the sound signal output device of claim 7, wherein the opening area of the open end of the reflector is S1, the area of the surface on one side of the first driver unit is S2, the length from the surface on one side of the first driver unit to the open end of the reflector is S3, and c is the speed of sound, the crossover frequency between the high-frequency band and the low-frequency band is lower than [Mathematical Formula 6]

Images