Partition system with speaker

Abstract

To prevent leakage of sound more than before by reducing a low-pitched sound component easy to sneak around in a direction other than a target direction.SOLUTION: The speaker-equipped partition system includes a plurality of wall surfaces of a partition 10 having first and second wall surfaces and a directional speaker 3 disposed on a first wall surface and having a sound emission direction with respect to the sound shielding portion, and the directional speaker includes a speaker unit (vibration unit 30), an enclosure 31 of the speaker unit, and a plurality of tubular resonance tubes 501 each having a tube and an opening. Each of the plurality of resonance tubes 501 constitutes a Helmholtz resonator. The directional speaker includes an outward-facing directional speaker having a sound emission direction other than a direction toward the acoustic shield and an inward-facing directional speaker having a sound emission direction toward the acoustic shield, and the outward-facing directional speaker outputs the masking sound.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] An embodiment of the present invention relates to a sound emitting device including a directional speaker. [Background technology]

[0002] Patent Document 1 discloses a speaker structure equipped with a bass reflex port as an example of a Helmholtz resonator. Patent Document 2 discloses a hands-free calling system that uses a simple partition to improve confidentiality in environments such as call centers or offices. In the hands-free calling system of Patent Document 2, a sound-absorbing panel is provided at a position spaced apart from the sound-emitting direction of a planar speaker. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-114934 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-091777 Summary of the Invention [Problem to be solved by the invention]

[0004] The Helmholtz resonator in Patent Document 1 is a bass reflex port for enhancing low frequency components. The sound emission direction of the planar speaker in Patent Document 2 is directed outward from each space surrounded by the partitions. [Means for solving the problem]

[0005] According to an embodiment of the present invention, a partition system with a speaker comprises a plurality of walls that form an acoustic shielding section that is partially open and partially shielded in a plan view, the walls having first and second walls, and a directional speaker that is arranged on the first wall and has a sound emission direction relative to the acoustic shielding section, the directional speaker comprising a speaker unit, an enclosure for the speaker unit, and an opening that forms a Helmholtz resonator, the directional speakers comprising an outward directional speaker that has a sound emission direction other than a direction relative to the acoustic shielding section, and an inward directional speaker that has a sound emission direction relative to the acoustic shielding section, and the outward directional speaker outputs masking sound. [Effects of the Invention]

[0006] According to the embodiment of the present invention, in a sound emitting device, low frequency components that tend to circulate in directions other than the intended direction can be reduced, and sound leakage can be prevented more effectively than in the past. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view showing a sound emitting device 1. [Figure 2] FIG. 2 is a plan view of the sound emitting device 1. [Figure 3] FIG. 2 is a front view of the sound emitting device 1. [Figure 4] FIG. 2 is a front view of the sound emitting device 1. [Figure 5] FIG. 2 is a cross-sectional view showing the structure of a flat speaker 3. [Figure 6] FIG. 2 is a block diagram showing the configuration of a flat speaker 3. [Figure 7] 10 is a diagram showing the relationship between the resonance frequency Fr and the lowest reproducible frequency Fmin of the vibration unit 30. FIG. [Figure 8] FIG. 10 is a cross-sectional view showing an example in which a port 32 is provided on the front surface. [Figure 9] FIG. 10 is a cross-sectional view of a case where a part of the partition 10 also serves as an enclosure. [Figure 10]10 is a cross-sectional view of an enclosure 31 having a resonance tube 501 on the rear surface thereof. [Figure 11] FIG. 10 is a cross-sectional view showing a modified example of the resonance tube 501. [Figure 12] 1 is a front view of a sound emitting device 1A equipped with a plurality of flat speakers 3. FIG. [Figure 13] 1 is a perspective view showing the configuration of a sound emitting device 1B having a flat speaker 3 on the top surface. [Figure 14] 10 is a perspective view showing the configuration of a sound emitting device 1C when a display 5 and a microphone 7 are provided. FIG. [Figure 15] FIG. 2 is a front view of the sound emitting device 1C. [Figure 16] FIG. 1 is a front view of a sound emitting device 1C when a user is sitting and operating a personal computer (PC) 9. [Figure 17] FIG. 1 is a perspective view of a sound emitting device 1E equipped with casters 110 that are assistive devices for assisting movement. [Figure 18] FIG. 10 is a front view showing a configuration when a masking sound is output. [Figure 19] FIG. 10 is a front view of a sound emitting device 1F equipped with flat speakers 3 on both sides, when applied to a semi-private room. [Figure 20] 1 is a block diagram showing the configuration of a planar speaker 3 that performs signal processing based on a sound signal picked up by a microphone (microphone 7 or microphone of PC 9). [Figure 21] FIG. 10 is a diagram showing the results of sound pressure measurement in the 500 Hz frequency band (1 / 1 octave band). [Figure 22] FIG. 1 shows the results of sound pressure measurements in a 1 kHz frequency band (1 / 1 octave band). DETAILED DESCRIPTION OF THE INVENTION

[0008] Fig. 1 is a perspective view showing a sound emitting device 1 of this embodiment, Fig. 2 is a plan view, and Figs. 3 and 4 are front views.

[0009] The sound emitting device 1 includes a partition 10 and a planar speaker 3. The partition 10 is an example of a plate material for forming a wall surface that is an acoustic shielding portion of the present invention. The planar speaker 3 is an example of a directional speaker of the present invention.

[0010] The partition 10 is a component for defining a semi-private room. The semi-private room has an acoustically shielding portion that is partially acoustically open and partially acoustically shielded. The walls of the partition 10 form the acoustic shielding portion of the semi-private room. The walls of the partition 10 form acoustic shielding portions at three locations: the right side, left side, and back of the semi-private room. The front and top of the semi-private room are acoustically open.

[0011] In the examples of Figures 1, 2, and 3, the partition 10 is made up of three members. Of the three members, two partitions 10 that form the right and left sides of the semi-private room face each other. The remaining one of the three members is located at the back of the semi-private room. However, the partition 10 does not have to be made up of three members. The partition 10 only needs to have parts that face each other. For example, the partition 10 may be a single piece. Furthermore, the wall surfaces of the partition 10 may be flat or curved.

[0012] The planar speaker 3 is placed on the wall surface of the partition 10. The sound emission direction of the planar speaker 3 faces the part of the wall surface on which the planar speaker 3 is installed. In other words, the sound emission direction of the planar speaker 3 faces the acoustic shielding part.

[0013] Furthermore, as shown in FIG. 3, the planar speaker 3 outputs sound to a predetermined range including the position of the user's head. For example, the planar speaker 3 outputs sound to a predetermined range at a predetermined height from the floor. As an example, the user listens to the sound from the planar speaker 3 while standing, as shown in FIG. 3. When listening while sitting in a chair, as shown in FIG. 4, the vertical mounting position of the planar speaker 3 relative to the wall surface can be lowered. Also, as shown in FIG. 2, the width of the planar speaker 3 in a planar view is approximately the same as the width (longitudinal length in a planar view) of the partition 10. Note that the width of the planar speaker 3 corresponds to the width A of the portion of the longitudinal length of the planar speaker 3 where the vibration unit is disposed in the planar view. Therefore, the user can hear the sound output by the planar speaker 3 no matter where they are in the semi-private room. However, in the present invention, the width of the planar speaker 3 may be shorter than the width of the partition 10. Note that "approximately the same" does not mean "completely the same" but includes "substantially the same." "Approximately the same" also includes cases where the width of the planar speaker 3 is slightly shorter than the width of the partition 10, as long as the effect of being able to hear the sound output by the planar speaker 3 from any position in the semi-private room is achieved.

[0014] The planar speaker 3 is connected to an information processing device (not shown), such as a personal computer. The planar speaker 3 receives an audio signal from the information processing device. The planar speaker 3 reproduces the audio signal and outputs sound. This allows the user to listen to the sound of content, for example. The information processing device may also be connected to an information processing device in a remote location, for example, via a network. The information processing device receives an audio signal from the remote location. This allows the user to listen to the voice of a user in a remote location connected via the network.

[0015] The planar speaker 3 is a thin, flat speaker. Unlike a normal cone speaker that outputs spherical sound waves, the planar speaker 3 outputs planar sound waves. The planar speaker 3 outputs sound with strong directivity in the front direction of the planar speaker 3 (the normal direction of the main surface). For example, if the planar speaker 3 is an electrostatic speaker, the minimum reproducible frequency Fmin is approximately 80 Hz to 250 Hz (the minimum reproducible frequency will be described later using FIG. 7).

[0016] As a result, the sound output from the planar speaker 3 is contained within the semi-private room. The height of the partition 10 is sufficiently longer than the height of the planar speaker 3. Therefore, the sound output from the planar speaker 3 bends upward and downward and does not leak out of the semi-private room. In particular, downward sound is completely blocked by the floor.

[0017] The width of the planar speaker 3 in the left-right direction is approximately the same as the width of the partition 10. Therefore, the sound output from the planar speaker 3 is more likely to bend in the left-right width direction than in the up-down direction. However, as will be described later, the planar speaker 3 further reduces the bending of the sound in the left-right direction due to the structure of the enclosure.

[0018] This allows the sound emission device 1 to prevent sound from leaking from the semi-private room. People outside the semi-private room will not hear the sound output from the planar speaker 3. A user of the sound emission device 1 can listen to the sound of content or hear the conversations of users in remote locations without worrying about sound leakage. Furthermore, people outside the semi-private room will not be bothered by the sound from the semi-private room.

[0019] Fig. 5 is a cross-sectional view showing the structure of the planar speaker 3. Fig. 6 is a block diagram showing the configuration of the planar speaker 3. The planar speaker 3 includes a vibration unit 30, an enclosure 31, a port 32, and a sound-absorbing material 35. The planar speaker 3 also includes an input unit 301, a signal processing unit 302, an amplifier unit 303, and a driver unit 304 as its hardware configuration.

[0020] The input unit 301 includes an analog audio I / F, a digital audio I / F, or a communication I / F such as a USB. The input unit 301 receives a sound signal from an information processing device. The signal processing unit 302 performs signal processing on the sound signal received by the input unit 301. For example, the signal processing unit 302 controls the level or adjusts the frequency characteristics of the sound signal. When the input unit 301 receives an analog sound signal, the signal processing unit 302 converts the signal into a digital sound signal and then processes the signal. The signal processing unit 302 converts the processed sound signal into an analog sound signal and outputs it to the amplification unit 303.

[0021] Amplifying section 303 amplifies the sound signal after being signal processed by signal processing section 302. Driving section 304 drives vibration unit 30 based on the sound signal amplified by amplifying section 303.

[0022] The vibration unit 30 is, for example, an electrostatic speaker unit. The vibration unit 30 has a structure in which a sheet-like diaphragm 30C is sandwiched between two fixed electrodes 30A and 30B. The driving unit 304 generates an electrostatic force by applying a voltage to the fixed electrodes 30A, 30B, and the diaphragm 30C. The driving unit 304 changes the electrostatic force by changing the voltage applied to the fixed electrodes 30A and 30B. The driving unit 304 vibrates the diaphragm 30C due to the change in electrostatic force. As a result, the planar speaker 3 outputs planar sound waves.

[0023] The enclosure 31 has an opening for placing the vibration unit 30 and is a rectangular box shape that is tall in the depth direction. Specifically, the enclosure 31 sandwiches the outer periphery of the vibration unit 30 with the opening on the front side. It is preferable that the enclosure 31 sandwiches the vibration unit 30 via a cushioning material such as rubber, foam, or cotton-like material. The vibration unit 30 outputs sounds with opposite phases to the front direction (outside the enclosure 31) and the rear direction (into the enclosure 31) of the enclosure 31. The enclosure 31 traps the sound output toward the rear direction inside.

[0024] 5, the enclosure 31 is provided with a sound-absorbing material 35 inside. The sound-absorbing material 35 absorbs sounds output from the rear direction of the vibration unit 30 that are above a predetermined frequency band. As a result, the sound-absorbing material 35 prevents vibration of the wall surface of the enclosure 31, reflected waves, and standing waves that are above the predetermined frequency band. Note that the sound-absorbing material 35 is not an essential component of the present invention.

[0025] The enclosure 31 has an opening on its side surface for forming the port 32. The port 32 has a shape that is elongated in the vertical direction of the planar speaker 3. The port 32 forms a Helmholtz resonator whose wall thickness of the enclosure 31 is length L in the tube axis direction.

[0026] The resonant frequency Fr of the Helmholtz resonator is given by the following formula (A): Fr=(c / 2π)·(S / VL), where V is the volume of the enclosure 31, c is the speed of sound, L is the length in the axial direction of the tube (the wall thickness of the enclosure 31), and S is the cross-sectional area of ​​the port 32. 1 / 2 The larger the cross-sectional area S of the port 32, the smaller the volume V of the enclosure 31, and the thinner the thickness L of the enclosure 31, the higher the resonant frequency Fr. The volume V of the enclosure 31 is expressed as V = Hw·d, where Hw is the area of ​​the face where the vibration unit 30 is located, and d is the depth of the enclosure 31 (the length in the left-right direction in FIG. 5). Furthermore, if A is the width of the face of the enclosure 31 where the vibration unit 30 is located (width A shown in FIGS. 2 and 5), and H is the height of the enclosure 31 (the length in the up-down direction when viewed from the front), the area Hw is expressed as Hw = A·H.

[0027] The resonant frequency Fr of the Helmholtz resonator of this embodiment is set to a high frequency, unlike a general bass reflex port. Hereinafter, the point of setting the resonant frequency Fr to be equal to or higher than the lowest reproducible frequency Fmin of the vibration unit 30 will be described with reference to FIG.

[0028] 7 is a diagram showing the relationship between the resonance frequency Fr and the lowest reproducible frequency Fmin of the vibration unit 30. The horizontal axis of the graph represents frequency, and the vertical axis represents level.

[0029] The reproducible lower limit frequency Fmin is, for example, a frequency that is −10 dB below the peak level. 2 When the area of ​​the vibration unit 30 is equivalent to A0 size, the frequency indicating -10 dB from the peak level is approximately 80 Hz. When the area of ​​the vibration unit 30 is equivalent to A4 size, the frequency indicating -10 dB from the peak level is approximately 250 Hz. Note that the minimum reproducible frequency Fmin is not limited to the frequency indicating -10 dB from the peak level. For example, it may be a frequency indicating -6 dB from the peak level.

[0030] As shown in FIG. 7, the resonance frequency Fr and the minimum reproducible frequency Fmin have the relationship of formula (B): Fr≧Fmin. In the low frequency band below the resonance frequency Fr, port 32 outputs the sound that is output toward the rear of vibration unit 30 as is. The sound output toward the rear of vibration unit 30 is in the opposite phase to the sound output toward the front. Therefore, port 32 outputs sound of the opposite phase in the low frequency band below the resonance frequency Fr. As a result, of the sound that travels from the front of vibration unit 30 to the sides, sound between the minimum reproducible frequency Fmin and the resonance frequency Fr is canceled by the opposite phase sound output from port 32. Furthermore, sound of frequencies below the minimum reproducible frequency Fmin is not output at an effective level.

[0031] As a result, even if sound output in the front direction of the vibration unit 30 goes around to the side, it is canceled by the sound of the opposite phase from the port 32. Therefore, the sound emitting device 1 can prevent sound leakage.

[0032] The higher the resonant frequency Fr is set, the higher the frequency of the sound that gets around the sides can be canceled, so it is preferable to set the resonant frequency Fr as high as possible within the structurally feasible range. It is preferable to use a thin material for the enclosure 31 that has high sound insulation. For example, it is preferable to use a metal material for the enclosure 31 that has a high surface density relative to its thickness and is highly rigid.

[0033] However, among sounds output toward the rear of the vibration unit 30, sounds in the high frequency band are absorbed by the sound-absorbing material 35. Therefore, when the enclosure 31 is filled with the sound-absorbing material 35, the relationship between the resonance frequency Fr and the effective lower limit frequency of the sound-absorbing material 35 should be set so that frequencies below the effective lower limit frequency of the sound-absorbing material 35 are reduced by the resonance frequency Fr to the lowest reproducible frequency Fmin. This allows the sound emitting device 1 to address sound leakage over a wide frequency range. For example, in the case of urethane foam with an effective lower limit frequency of 1.5 kHz, the resonance frequency Fr should be set near 1.5 kHz. In addition, in the case of glass wool with an effective lower limit frequency of 500 Hz, the resonance frequency Fr should be set near 500 Hz. The effective lower limit frequency is determined by the thickness (length in the front-to-rear direction) of the sound-absorbing material, including the air space behind it. The frequency corresponding to four times the thickness of the sound-absorbing material corresponds to the effective lower limit frequency. In other words, the thickness of the sound-absorbing material corresponds to 0.25 times the wavelength of the sound waves to be absorbed.

[0034] 2 and 5, the width A of the enclosure 31 preferably has a length that is a certain amount relative to the wavelength of the sound wave corresponding to the resonance frequency Fr so that sound waves output toward the front of the vibration unit 30 are less likely to bend toward the rear. The rear of the enclosure 31 vibrates due to sound output toward the rear of the vibration unit 30. However, sound at or below the resonance frequency Fr is output directly from the port 32, so the sound pressure inside the enclosure 31 does not increase. Therefore, sound at or below the resonance frequency Fr is less likely to vibrate the rear. Therefore, the width A of the rear of the enclosure 31 preferably has a certain amount relative to the wavelength λ of the sound wave corresponding to the resonance frequency Fr. Theoretically, to prevent sound waves output toward the front of the vibration unit 30 from bending toward the rear, a path difference of 0.5λ or more is sufficient for the sound waves to bypass the enclosure 31. Therefore, when the enclosure 31 itself is used as a sound barrier, it is preferable to satisfy at least the formula (C): A≧0.25λ in order to prevent sound output toward the front of the vibration unit 30 from bending toward the rear. Furthermore, it is more preferable that the width A and the resonant frequency Fr satisfy the relationship of the mathematical formula (D)A≧0.5λ.

[0035] Figures 21 and 22 are diagrams showing the results of sound pressure measurement. The sound pressure measurement results shown in Figures 21 and 22 show sound pressure values ​​(relative values) at 30° intervals, with the sound pressure value at 0° in the front direction being the reference (0 dB) when the front direction of the planar speaker 3 is 0° and the rear direction is 180°.

[0036] The width A of the enclosure 31 at the time of measurement in Figures 21 and 22 is 230 mm. Figure 21 shows the measurement results in a sound wave frequency band of approximately 500 Hz (1 / 1 octave band) (wavelength band of approximately 680 mm), and Figure 22 shows the measurement results in a sound wave frequency band of approximately 1 kHz (1 / 1 octave band) (wavelength band of approximately 340 mm). The solid lines shown in Figures 21 and 22 show the measurement results when the enclosure 31 is equipped with the port 32. The dashed lines show the measurement results when the enclosure 31 is not equipped with the port 32, as a reference example.

[0037] In the example of Figure 21, the wavelength λ = 680 mm, and the width A of the enclosure 31 is 230 mm. In other words, the relationship A ≥ 0.5λ is not satisfied. In this case, the sound pressure value in the rear direction does not change regardless of whether or not the port 32 of the enclosure 31 is present, because the influence of sound waves that circumvent from the front side to the rear side is large. In other words, when the relationship A ≥ 0.5λ is not satisfied, the effect of the port 32 in suppressing sound waves in the rear direction is not exerted.

[0038] In contrast, in the example of Fig. 22, the width A of the enclosure 31 is 230 mm for a wavelength λ = 340 mm. That is, the relationship A ≥ 0.5λ is satisfied. In the example of Fig. 22, when the enclosure 31 is provided with the port 32, the sound pressure value in the rear direction is lower than when the port 32 is not provided. That is, when the relationship A ≥ 0.5λ is satisfied, it can be seen that the port 32 exerts the effect of suppressing sound waves in the rear direction.

[0039] This allows the enclosure 31 to suppress sound output in the rear direction due to vibrations at the rear surface.

[0040] The position of the port 32 is not limited to the side surface of the enclosure 31. FIG. 8 is a cross-sectional view showing an example in which the port 32 is provided on the front surface. The enclosure 31 shown in FIG. 8 has a width greater than the width of the vibration unit 30. The enclosure 31 is provided with ports 32 on the left and right sides of the front surface. In this case, sound that is output in the front direction of the vibration unit 30 and tries to circumvent the side surface is canceled by sound of the opposite phase that is output from the port 32 provided on the front surface of the enclosure 31. In other words, the opening that constitutes the port 32 is oriented in a direction that intersects with the sound emission direction of the speaker unit, but is not opposite the sound emission direction, or is oriented in the same direction as the sound emission direction of the speaker unit.

[0041] Note that a portion of the partition 10 may also serve as an enclosure. Fig. 9 is a cross-sectional view of a case in which a portion of the partition 10 also serves as an enclosure. In this case, the enclosure 31 is contained within the partition 10. This prevents the sound emitting device 1 from protruding in the front direction of the flat speaker 3. Therefore, the sound emitting device 1 is thin and has an excellent design.

[0042] The planar speaker 3 may also be covered with an acoustically open cover such as mesh or punched metal, etc. In this case, the planar speaker 3 is less noticeable, and the sound emitting device 1 has a more excellent design.

[0043] FIG. 10 is a cross-sectional view of an enclosure 31 provided with a resonance tube 501 on the rear surface thereof. A cylindrical resonance tube 501 is provided on the rear surface of the enclosure 31. The resonance tube 501 has a tube having a certain length in the left-right direction and an opening. Although not shown, a plurality of resonance tubes 501 are provided in the up-down direction. Each of the plurality of resonance tubes 501 constitutes a Helmholtz resonator. The plurality of resonance tubes 501 have different tube lengths.

[0044] Sound incident on the opening resonates at a specific resonance frequency depending on the length of the tube. The resonating sound is in the opposite phase to the incident sound. Therefore, the resonance tube 501 exerts a sound absorption effect at a specific frequency near the opening. When multiple resonance tubes 501 have different resonance frequencies, the resonance tubes exert a sound absorption effect across a predetermined frequency band.

[0045] This further reduces the amount of sound that leaks around the sides, and therefore the sound emitting device 1 can further prevent sound leakage.

[0046] Fig. 11 is a cross-sectional view showing a modified example of the resonance tube 501. As shown in Fig. 11, the resonance tube 501 may be provided in the partition 10. The opening of the resonance tube 501 may also be provided on the front or flat side of the partition 10. In this case, the sound waves reflected on the wall surface of the partition 10 interfere with the resonant sound, which can also produce a confusion effect. Therefore, the sound emission device 1 can also have a sound adjustment function that adjusts the resonance of the sound while reducing the sound that wraps around the sides.

[0047] FIG. 12 is a front view of a sound emitting device 1A equipped with a plurality of planar speakers 3. In the example of FIG. 12, the sound emitting device 1A is equipped with a plurality of planar speakers 3 that face each other. In this case, the user can hear the sound of the planar speakers 3 from both the front and rear directions of the user. In this case, the sound emitting device 1A can also prevent sound leakage. Note that the plurality of planar speakers 3 do not need to face each other.

[0048] Fig. 13 is a perspective view showing the configuration of a sound emitting device 1B having a planar speaker 3 on the top surface. As shown in Fig. 13, the planar speaker 3 may be placed so as to be perpendicular to the main surface of the partition 10, or may be placed so as to be inclined at a predetermined angle. In this case, the planar speaker 3 outputs plane waves toward the floor, which is an example of an acoustic shielding portion. In this case, the sound emitting device 1B can also prevent sound from leaking.

[0049] FIG. 14 is a perspective view showing the configuration of sound emitting device 1C when it is equipped with a display 5 and a microphone 7. FIG. 15 is a front view. Display 5 and microphone 7 are provided on a partition 10 arranged at the back of the semi-private room. Display 5 receives and displays image data from an information processing device installed in a remote location. Display 5 displays image data captured by a camera installed in a remote location. Microphone 7 picks up voice uttered by the user and transmits it to the information processing device installed in a remote location. Planar speaker 3 receives and emits sound signals from the information processing device installed in a remote location. In this way, sound emitting device 1C realizes remote video conferencing.

[0050] The microphone 7 is installed near the top of the partition 10. That is, as shown in Fig. 15, the microphone 7 is placed outside the directivity range of the planar speaker 3. Therefore, the microphone 7 does not pick up the sound from a distant location output from the planar speaker 3. Therefore, the sound emitting device 1C suppresses the occurrence of echoes.

[0051] 16, even when a user sits and operates a personal computer (PC) 9, the microphone provided in the PC 9 is outside the range of the directivity of the planar speaker 3. In this case as well, the sound emitting device 1C can suppress the occurrence of echoes.

[0052] 17 is a perspective view of a sound emitting device 1E equipped with casters 110, which are assistive devices for assisting movement. The sound emitting device 1E is equipped with casters 110 that support the lower part of the partition 10 to prevent it from tipping over in the thickness direction and assist movement. The other configurations are the same as those of the sound emitting device 1.

[0053] A user can easily create a semi-private room even in an open space by simply moving one or more sound emission devices 1E to any position using the casters 110 and blocking the view and sound. A semi-private room configured in this way can prevent sound leakage from the semi-private room, just like the sound emission device 1 described above, so that people outside the semi-private room cannot hear the sound output from the flat speaker 3. A user of the sound emission device 1 can listen to the sound of content or hear the conversations of users in remote locations without worrying about sound leakage. Furthermore, people outside the semi-private room will not be bothered by the sound from the semi-private room.

[0054] Because the sound emitting device 1E can be easily moved, the planar speaker 3 may be installed facing outward from the semi-private room. When the planar speaker 3 is installed facing outward from the semi-private room, the planar speaker 3 outputs a masking sound. The sound emitting device 1E may be provided with a planar speaker 3 on each of the two wall surfaces. In this case, the sound emitting device 1E outputs the sound of the content or the audio of the remote conference from the planar speaker 3, which is a first directional speaker installed facing inward, and outputs the masking sound from the planar speaker 3, which is a second directional speaker installed on the opposite wall (facing outward).

[0055] Fig. 18 is a front view showing a configuration for outputting masking sound. In the example of Fig. 18, the sound emitting device 1E is placed on the back, right side, and left side of a semi-private room. All of the planar speakers 3 of the sound emitting device 1E are set to face outward.

[0056] The planar speaker 3 outputs masking sounds. The masking sounds prevent third parties from understanding what is being said by people conversing in a semi-private room. The masking sounds preferably include a distracting sound that disrupts speech, a continuously occurring background sound, and an intermittent sound effect. The distracting sound is, for example, a human voice altered on the time axis or frequency axis to make it lexically meaningless (unintelligible). The distracting sound has a human voice quality but cannot be recognized as a conversational voice emitted by a human. Therefore, distracting sounds can cause discomfort to listeners and, if heard for a long time or at an excessively high volume, can be unpleasant. Therefore, it is preferable to combine the distracting sound with a background sound and a sound effect. The background sound is, for example, a babbling brook or the rustling of trees, a sound that is difficult for third parties to notice and is not unpleasant. This allows the background sound to increase the background noise level and make the distracting sound less noticeable, thereby reducing the discomfort and discomfort of the distracting sound. The special sound is a highly special sound such as musical tones that are generated intermittently. This allows the special sound to draw the attention of third parties to the special sound, making the psychoacoustic discomfort of the disturbing sound less noticeable.

[0057] 18, all of the planar speakers 3 of the sound emission device 1E are set to face outward. However, the planar speakers 3 may be installed to face inward. The planar speakers 3 installed to face inward output the target sound (sound of content, audio of a remote conference, etc.).

[0058] Fig. 19 is a front view of a sound emitting device 1F equipped with planar speakers 3 on both sides, when applied to a semi-private room. The sound emitting device 1F is equipped with planar speakers 3 on both sides. In the example of Fig. 19, the sound emitting device 1F is placed on the right and left sides of the semi-private room. A sound emitting device 1E equipped with a planar speaker 3 on only one side is placed at the back of the semi-private room.

[0059] In this case, the sound emission device 1F outputs a masking sound from the planar speaker 3, which is the second directional speaker installed facing outward, and outputs a target sound (such as the sound of content or the audio of a remote conference) from the planar speaker 3, which is the first directional speaker installed facing inward.

[0060] 20 is a block diagram showing the configuration of the planar speaker 3 that performs signal processing based on a sound signal picked up by a microphone (microphone 7 or microphone of PC 9). The hardware configuration is the same as that shown in FIG.

[0061] The input unit 301 receives a sound signal related to sound picked up by a microphone (microphone 7 or the microphone of the PC 9). The signal processing unit 302 adjusts the volume of the sound signal to be output to a subsequent stage according to the volume of the sound signal related to the sound picked up by the microphone. For example, the signal processing unit 302 measures in advance the maximum volume at which sound from the planar speaker 3 does not leak from a semi-private room and the volume of the sound picked up by the microphone at that time. Thereafter, the signal processing unit 302 adjusts the volume based on the volume of the sound signal related to the sound picked up by the microphone and the volume of the sound picked up by the microphone measured in advance. This allows the volume to be adjusted to an optimal level without the user having to adjust the volume. The signal processing unit 302 may also adjust the frequency characteristics of the sound signal instead of or in addition to the volume.

[0062] Furthermore, when outputting a masking sound, the signal processing unit 302 may adjust the volume of the masking sound according to the volume of the sound signal related to the sound picked up by the microphone. In this case, the signal processing unit 302 performs processing to suppress the volume to the minimum necessary to exert the masking sound effect.

[0063] It is preferable that the signal processing unit 302 performs a fade-in process when the masking sound starts to be output, and a fade-out process when the masking sound stops, thereby making the masking sound less noticeable to third parties.

[0064] Furthermore, when outputting masking sound, the planar speaker 3 may be divided into multiple units. In this case, the signal processing unit 302 controls the sound emission timing of the multiple units to control the combined wavefront of the sound waves output from the multiple units. This allows the signal processing unit 302 to control the shape of the wavefront and control the directivity. The masking sound can be directed in any direction. Note that the signal processing unit 302 may control the sound emission timing by delaying the sound signals of multiple channels using digital signal processing, or may delay the analog sound signals supplied to each planar speaker 3 using an analog circuit.

[0065] The signal processing unit 302 may also perform processing to reduce the sense of localization of the planar speaker 3. For example, the signal processing unit 302 convolves the inverse function of a transfer function (head-related transfer function) from the planar speaker 3 to the user's head, which is acquired in advance, into the sound signal. This prevents the sound from the planar speaker 3 installed behind the user from being localized backward, allowing the user to hear the sound with a more natural impression.

[0066] The signal processing unit 302 may also perform low-pass filtering to cut off a band of a predetermined frequency (e.g., 5 kHz) or higher. Sound localization in the front-rear and up-down directions depends on frequency characteristics of 5 kHz or higher. Therefore, the signal processing unit 302 can also reduce the sense of localization of the planar speaker 3 by performing low-pass filtering to cut off a band of a predetermined frequency (e.g., 5 kHz) or higher.

[0067] Furthermore, the signal processing unit 302 may perform processing to add reverberation sounds. By adding reverberation sounds, the signal processing unit 302 can also reduce the sense of localization of the direct sound.

[0068] The description of the present embodiment should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined not by the above-described embodiments but by the claims. Furthermore, the scope of the present invention is intended to include all modifications within the meaning and scope of the claims.

[0069] For example, in this embodiment, a planar speaker is shown as an example of a directional speaker. However, the directional speaker may be, for example, a dynamic speaker. Furthermore, the directional speaker may be an array speaker formed by arranging a plurality of dynamic speakers.

[0070] The sound emitting device of this embodiment has been exemplified as including a partition 10 and a planar speaker 3. However, the partition 10 is not essential. For example, the planar speaker 3 can be suspended from the ceiling. In this case, the sound emitting device includes a speaker unit and an enclosure for the speaker unit. The sound emitting device may also include a support member that supports the bottom surface (the lower side surface) of the enclosure from the floor surface.

[0071] This application is based on a Japanese patent application (Patent Application No. 2019-199229) filed on October 31, 2019, and an international patent application PCT / JP2020 / 040439 based on a Japanese patent application (Patent Application No. 2019-199230) filed on October 31, 2019, the contents of which are incorporated herein by reference. [Explanation of symbols]

[0072] 1,1A,1B,1C,1R,1F…Sound emitting device 3...Planar speaker 5. Display 7...Mike 9...PC 10...Partition 30...Vibration unit 30A,30B…Fixed electrode plate 30C…diaphragm 31...Enclosure 32...Port 35...Sound absorbing material 110...Caster 301...input section 302...Signal processing unit 303...Amplification section 304...Drive unit 501…Resonance tube

Claims

1. a plurality of walls constituting an acoustic shielding portion that is partly open and partly shielded in a plan view, the walls having first and second walls; a directional speaker disposed on the first wall surface and having a sound emitting direction relative to the sound shielding portion; Equipped with The directional speaker comprises: A speaker unit, an enclosure for the speaker unit; an opening that forms a Helmholtz resonator; A speaker-equipped partition system comprising: the directional speakers include an outward directional speaker having a sound emission direction other than a direction relative to the sound-shielding part, and an inward directional speaker having a sound emission direction relative to the sound-shielding part, The outward directional speaker outputs a masking sound. Partition system with speaker.

2. A resonance tube is provided on the first wall surface.

2. The speaker-equipped partition system according to claim 1.

3. The resonance tube is provided outside the enclosure. The speaker-equipped partition system according to claim 2.

4. 4. The speaker-equipped partition system according to claim 1, wherein a volume V of the enclosure, an area S of the opening, and a plate thickness L of the enclosure satisfy a mathematical formula (2) including a sound speed c. Formula (2): Fr = (c / 2π) (S / VL) 1 / 2

5. 5. The speaker-equipped partition system according to claim 1, wherein a width A of the enclosure and a wavelength λ of a sound wave corresponding to the resonant frequency Fr satisfy the following formula (3). Formula (3): A≧0.25λ

6. 6. The speaker-equipped partition system according to claim 1, wherein a width A of the enclosure and a wavelength λ of a sound wave corresponding to the resonant frequency Fr satisfy the following formula (4). Formula (4): A≧0.5λ

7. the opening is oriented in a direction intersecting the sound emission direction of the speaker unit and other than the direction opposite to the sound emission direction; or The opening is oriented in the same direction as the sound output direction of the speaker unit.

7. The speaker-equipped partition system according to claim 1.

8. Further comprising a sound absorbing material inside the enclosure. The speaker-equipped partition system according to any one of claims 1 to 7.

9. The resonant frequency Fr of the Helmholtz resonator is equal to or lower than the effective lower limit frequency of the sound absorbing material. The speaker-equipped partition system according to claim 8.

10. The speaker unit and the enclosure are connected via a buffer material. The speaker-equipped partition system according to any one of claims 1 to 9.

11. A part of the wall surface is the enclosure. The speaker-equipped partition system according to any one of claims 1 to 10.

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