JP2016197833A - Speaker device and manufacturing method for speaker device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a flat sound pressure frequency characteristics, without narrowing the reproducible frequency band.SOLUTION: A speaker device includes a speaker (9) having a diaphragm radiating a sound by vibrating, and a baffle plate (27) arranged on the whole circumference of the speaker. The central axis of the diaphragm of the speaker is parallel with the normal direction of the baffle plate. The baffle plate has a through hole (29), formed in any one of a line of a first similar figure drawn to become a range of homothetic ratio of 5:1 through 5:3 for the shape of the edge of the baffle plate, with the center of the speaker as the center of similarity, or on a line of a second figure formed by rotating the first figure around the center of the speaker, or on a line of a third figure formed by inverting the first figure for a line passing the center of the speaker.SELECTED DRAWING: Figure 16

Description

  The present invention relates to a speaker device used for radiating sound in a television or a car audio, and a method for manufacturing the speaker device.

  A conventional speaker device has a cabinet that encloses the back side of a baffle plate to which a speaker is attached in a box shape so that sound radiated from the front and back surfaces of the speaker with positive and negative sound pressures does not interfere. In addition, the baffle plate prevents the sound diffracted from the end of the baffle plate from interfering with the sound radiated directly from the speaker to the sound receiving point and causing a peak (maximum) or dip (minimum) in the sound pressure frequency characteristics. A cutout portion is provided in the outer peripheral portion of (see, for example, Patent Document 1).

JP 2013-126033 A

However, the prior art has the following problems.
In the speaker device as in Patent Document 1, the air in the enclosed box becomes an air spring, and the lowest resonance frequency of the speaker moves to a higher frequency. As a result, there is a problem that the reproducible frequency band becomes narrow.

  The present invention has been made to solve the above-described problems, and provides a speaker device having a flat sound pressure frequency characteristic and a method for manufacturing the speaker device without narrowing a reproducible frequency band. It is aimed.

  A speaker device according to the present invention includes a speaker including a diaphragm that radiates sound by vibration, and a baffle plate disposed around the periphery of the speaker, and includes a central axis of the speaker diaphragm and a baffle plate. In the speaker device arranged so that the normal direction is parallel, the baffle plate has a through-hole, and the hole has the shape of the edge of the baffle plate with the center of the speaker as a similar center. On the other hand, on the line of the first figure, which is a similar figure drawn so as to be in the range of the similarity ratio of 5: 1 to 5: 3, or on the second figure obtained by rotating the first figure about the center of the speaker. It is formed either on the line or on the line of the third graphic obtained by inverting the first graphic with respect to the line segment passing through the center of the speaker.

  In addition, a method for manufacturing a speaker device according to the present invention includes a speaker including a diaphragm that emits sound by vibration, and a baffle plate disposed around the periphery of the speaker, and the center of the diaphragm of the speaker A method of manufacturing a speaker device in which a normal direction of a shaft and a baffle plate is parallel to the baffle plate, with the center of the speaker being a similar center and the shape of the edge of the baffle plate On the line of the first figure, which is a similar figure drawn so as to be in the range of the similarity ratio of 5: 1 to 5: 3, or on the line of the second figure obtained by rotating the first figure about the center of the speaker, Alternatively, the method includes a step of forming a through hole over a part or the entire circumference of the line on any of the lines of the third graphic obtained by inverting the first graphic with respect to the line segment passing through the center of the speaker.

  According to the present invention, a hole is provided at an appropriate position of the baffle plate, and additional diffracted sound that reaches the listening point on the front side of the speaker is generated from the back side of the speaker via the hole portion, so that the baffle is formed from the back side of the speaker. A configuration is provided in which the diffracted sound that reaches the listening point via the edge of the plate is canceled by the additional diffracted sound. As a result, a speaker device having a flat sound pressure frequency characteristic and a method for manufacturing the speaker device can be obtained without narrowing the reproducible frequency band regardless of the shape of the edge of the baffle plate.

It is explanatory drawing which shows the mechanism in which a sound generate | occur | produces from a speaker. It is explanatory drawing which shows a mode that the sound has generate | occur | produced from the diaphragm. It is a schematic diagram of the conventional speaker apparatus using a baffle board. It is a positive / negative graph of the relative pressure in the conventional speaker apparatus. It is a front view of the conventional speaker apparatus. 6 is a graph of sound pressure frequency characteristics when the speaker device of FIG. 5 is used. It is a positive / negative graph of the relative pressure in the conventional speaker apparatus. It is a positive / negative graph of the relative pressure in the conventional speaker apparatus. It is a positive / negative graph of the relative pressure in the conventional speaker apparatus. It is a positive / negative graph of the relative pressure in the conventional speaker apparatus. 1 is a schematic diagram of a speaker device according to Embodiment 1 of the present invention. It is a graph of the sign positive / negative of the relative pressure in the speaker apparatus by Embodiment 1 of this invention. It is a sign positive / negative graph of the relative pressure in the speaker apparatus of Embodiment 1 of this invention. It is a sign positive / negative graph of the relative pressure in the speaker apparatus of Embodiment 1 of this invention. It is the graph which showed the effect of the additional diffraction sound in Embodiment 1 of this invention. It is a front view of the speaker apparatus in Embodiment 2 of this invention. It is a graph of a sound pressure frequency characteristic when using the speaker apparatus of FIG. 16 in Embodiment 2 of this invention. It is a sign positive / negative graph of the relative pressure in the speaker apparatus by Embodiment 2 of this invention. It is a sign positive / negative graph of the relative pressure in the speaker apparatus by Embodiment 2 of this invention. It is a sign positive / negative graph of the relative pressure in the speaker apparatus by Embodiment 2 of this invention. It is a sign positive / negative graph of the relative pressure in the speaker apparatus by Embodiment 2 of this invention. It is a front view of the speaker apparatus provided with the structure different from previous FIG. 16 in Embodiment 2 of this invention. It is a front view of the conventional speaker apparatus provided with the square baffle board. It is a graph of the sound pressure frequency characteristic of the conventional speaker apparatus shown in FIG. It is a front view of the speaker apparatus provided with the baffle board in Embodiment 3 of this invention. 26 is a graph of sound pressure frequency characteristics when the baffle plate shown in FIG. 25 is used in the speaker device according to Embodiment 3 of the present invention. It is a front view of the speaker apparatus in Embodiment 4 of this invention. It is a graph of the sound pressure frequency characteristic when using the speaker device of FIG. 27 in Embodiment 4 of the present invention. It is a front view of the speaker apparatus different from previous FIG. 27 in Embodiment 4 of this invention. 30 is a graph of sound pressure frequency characteristics when the speaker device of FIG. 29 according to Embodiment 4 of the present invention is used. It is a front view of the speaker apparatus in Embodiment 5 of this invention. It is a graph of the sound pressure frequency characteristic when using the baffle board which made width X 1 / 100L in Embodiment 5 of this invention. It is a graph of the sound pressure frequency characteristic when using the baffle board which made width X 1 / 200L in Embodiment 5 of this invention. It is a graph of the sound pressure frequency characteristic when using the baffle board which made width X 1 / 40L in Embodiment 5 of this invention. It is a graph of the sound pressure frequency characteristic when using the baffle board which made width X 1 / 30L in Embodiment 5 of this invention. It is a graph of the sound pressure frequency characteristic when using the baffle board which made width X 1 / 15L in Embodiment 5 of this invention. It is a graph which shows the relationship between the planarization amount in Embodiment 5 of this invention, and the width | variety of a hole. It is a front view of the speaker apparatus in Embodiment 6 of this invention. It is a front view of the speaker apparatus different from FIG. 38 in Embodiment 6 of this invention. It is a front view of the speaker apparatus in Embodiment 7 of this invention.

  Hereinafter, preferred embodiments of a speaker device and a method of manufacturing the speaker device of the present invention will be described with reference to the drawings. In the following description, first, the contents and problems of the prior art will be described with reference to FIGS. 1 to 10, and then the features of the present application will be described in detail with reference to FIG.

Embodiment 1 FIG.
FIG. 1 is an explanatory diagram showing a mechanism for generating sound from a speaker. The diaphragm 1, the bobbin 2, and the voice coil 3 are attached to the frame 5 in this order using the roll edge 4 as a spring. The position of the voice coil 3 is adjusted so as to be positioned in the magnetic field 6 generated from the permanent magnet 7.

  A force is generated by passing a current through the voice coil 3, and the force is transmitted to the diaphragm 1 through the bobbin 2, so that the diaphragm 1 vibrates and a pressure difference is generated in the air in the vicinity of the diaphragm 1. This pressure difference propagates through the air and becomes sound.

  FIG. 2 is an explanatory diagram illustrating a state in which sound is generated from the diaphragm 1. Here, a case where force is applied to the diaphragm 1 and the diaphragm 1 moves upward will be considered. At this time, the air above the diaphragm is compressed and the pressure is higher than the surrounding air. On the other hand, the air below the diaphragm 1 expands and the pressure becomes lower than the surrounding air.

  Conversely, when considering the case where the diaphragm 1 moves downward, the air on the upper side of the diaphragm 1 expands and the pressure becomes lower than the surrounding air. On the other hand, the air below the diaphragm 1 is compressed, and the pressure becomes higher than the surrounding air.

  Here, the relative pressure when the pressure is higher than that of the surrounding air is expressed as positive, and the relative pressure when the pressure is lower than that of the surrounding air is expressed as negative. In this case, it means that sounds P1 and P2 having opposite signs of relative pressure are generated on the upper side and the lower side of the diaphragm 1, that is, on the front side and the back side of the diaphragm 1.

  Also, the sound is a longitudinal wave, and the sign of this pressure changes over time. Here, a cycle in which the pressure is positive and negative once is called one cycle. The number of times this cycle is repeated per second is called a frequency. For example, with a sound of 100 Hz, the sign positive / negative cycle of relative pressure is repeated 100 times per second.

  Also, the sound has a constant speed under the same medium, the same temperature, and pressure regardless of the frequency. For example, in dry air at 20 ° C. and atmospheric pressure, the sound travels about 343 m per second. The sound of 100 Hz repeats the sign of the relative pressure 100 times in this. For this reason, the sound advances about 3.43 m during one cycle. This length is called wavelength λ.

  The higher the frequency, the shorter the wavelength λ, and the lower the frequency, the longer the wavelength λ. When generating sound from a single speaker, sounds generated from both the front and back sides of the speaker interfere with each other, and the sound pressure of the sound increases between sounds with the same sign of relative pressure at the listening point. The sound pressure of the sound becomes small between sounds having opposite signs of relative pressure at the listening point.

  The way of sound interference is greatly related to the length of the wavelength λ, so the sound pressure of the sound varies depending on the frequency. This is called the sound pressure frequency characteristic of the speaker. This indicates that the sound as desired to be reproduced using the speaker device cannot be reproduced due to the sound interference. In order to prevent this interference, a method using a baffle plate is generally taken.

  FIG. 3 is a schematic diagram of a conventional speaker device using the baffle plate 8. The speaker 9 actually has a three-dimensional shape, but in FIG. 3 and subsequent figures, the speaker 9 is simply expressed as a flat disk and a point.

  A speaker 9 is mounted on the surface of the baffle plate 8, and a sound (direct sound) that reaches the listening point 13 through the path 11 from the front side of the speaker 9 and an arbitrary edge of the baffle plate 8 from the back side of the speaker 9. There is a sound (diffracted sound) that reaches the listening point 13 through the path 12 via the point 10. The path 12 is a path that passes through an arbitrary point 10 in the entire circumference of the edge of the baffle plate 8, and the diffracted sound reaches the listening point 13 from all the outer circumferences.

  The length of the direct sound path 11 is the path length R 1 from the speaker 9 to the listening point 13. On the other hand, the length of the path 12 of the diffracted sound is the path length L from the speaker 9 to an arbitrary point 10 on the edge of the baffle plate 8 and the path from the arbitrary point 10 on the edge of the baffle plate 8 to the listening point 13. This is the sum of the length R2.

  FIG. 4 is a graph of the sign of relative pressure in a conventional speaker device, with the relative pressure on the vertical axis and the path length of the sound wave on the horizontal axis. A solid line 11 indicates a direct sound passing through the path 11 (hereinafter referred to as direct sound 11), and a broken line 12 indicates a diffracted sound passing through the path 12 (hereinafter referred to as diffracted sound 12). The sign of the relative pressure when the path length is 0 indicates the relative pressure when the direct sound 11 and the diffracted sound 12 are generated on the front and back of the speaker, and the signs are opposite to each other. It becomes.

  The sign of the pressure when the path length of the direct sound 11 is R1, that is, the relative pressure at the point 14, and the sign of the pressure when the path length of the diffracted sound 12 is the sum of L and R2, that is, The relative pressure at the point 15 indicates the sign of the pressure in each path at the listening point 13. At a point where the sound receiving point 13 is sufficiently far from the front of the speaker 9 (for example, 20L <R1), it can be approximated as R1 = R2. For this reason, the path difference between the direct sound 11 and the diffracted sound 12 at a point sufficiently far from the front of the speaker 9 is L.

  FIG. 5 is a front view of a conventional speaker device. Specifically, the shape of the edge of the baffle plate 17 is set to the true value of the radius L with the speaker 9 as the center so that all the path lengths from the speaker 9 to arbitrary points on the edge of the baffle plate 17 are equal to L. It is a schematic diagram of the speaker apparatus made into the circle. FIG. 6 is a graph of sound pressure frequency characteristics when the speaker device of FIG. 5 is used. The vertical axis represents relative sound pressure, and the horizontal axis represents frequency.

  This analysis is performed using commercially available analysis software Virtual. lab (manufactured by LMS) was used. In this analysis, the speaker 9 is a point sound source and is arranged on both sides of the 1 mm thick baffle. In addition, the two point sound sources have opposite signs of relative pressure. Furthermore, the radius L of the baffle plate 17 of the speaker device was 30 mm, and the distance R1 from the surface of the speaker 9 to the sound receiving point was 1000 mm.

  A point (peak) at which the relative sound pressure is maximized and a point (dip) at which the relative sound pressure is minimized are designated as peak 18, dip 19, and peak 20 in order from the lowest frequency. At a frequency lower than the peak 18, the sound pressure decreases as the frequency decreases.

  7 to 10 are graphs showing the sign of relative pressure in a conventional speaker device. Specifically, FIG. 7 is an enlarged graph of the region 16 in FIG. 4 among the graphs showing the relative pressure at the listening point 13 at a frequency lower than the frequency of the peak 18 in FIG. FIG. 8 is an enlarged graph of the region 16 in FIG. 4 among the graphs showing the relative pressure at the listening point 13 at the frequency of the peak 18 in FIG.

  FIG. 9 is an enlarged graph of the region 16 in FIG. 4 among the graphs showing the relative pressure at the listening point 13 at the frequency of the dip 19 in FIG. Further, FIG. 10 is an enlarged graph of the region 16 in FIG. 4 among the graphs showing the relative pressure at the listening point 13 at the frequency of the peak 20 in FIG.

  The time was adjusted so that the sign of the relative pressure of the direct sound 11 at the listening point 13 became a positive maximum value. As shown in FIG. 7, the relative pressure 14 of the direct sound 11 at the listening point 13 and the relative pressure of the diffracted sound 12 at the listening point 13 at a low frequency such that a quarter of the wavelength λ is larger than L. The sign plus / minus 15 of the relative pressure of the diffracted sound 12 approaches the negative maximum as the sign of 15 is reversed, the frequency is decreased, and the wavelength λ is increased. For this reason, the sound pressure decreases as the frequency becomes lower than the frequency of the peak 18.

  As shown in FIG. 9, the sign of the relative sound pressure 14 of the direct sound 11 and the relative pressure 15 of the diffracted sound 12 is reversed even when L is a frequency that is exactly the same length as the wavelength λ. For this reason, the sound pressure frequency characteristic is a dip.

  On the other hand, as shown in FIGS. 8 and 10, the sign of the relative pressure 15 of the diffracted sound 12 is relative to that of the direct sound 11 at a frequency where L is exactly one half or three half of the wavelength λ. The sign is the same as that of the pressure 14. For this reason, the sound pressure frequency characteristic has a peak.

  The reason that the sound pressure difference between the peak and the dip becomes smaller as the frequency becomes higher is that the higher the frequency, the less the diffraction becomes, and the less the interference between the direct sound 11 and the diffracted sound 12 becomes.

  The maximum sound pressure difference 21 between the peak and the dip in FIG. 6 is 10 dB. Thus, in the conventional baffle plate 17, the sign positive / negative relationship of the relative pressure 15 of the diffracted sound 12 directly affects the direct sound 11. In particular, there is a problem that the sound pressure difference 21 between the first peak 18 and the dip 19 increases from a low frequency.

Therefore, a speaker device according to the present invention for solving such a problem will be described in detail with reference to FIG.
FIG. 11 is a schematic diagram of the speaker device according to Embodiment 1 of the present invention. Between the speaker 9 and an arbitrary point 10 on the edge of the baffle plate 22, a hole 23 is formed at a position away from the speaker 9 by L 1, and a new diffracted sound passing through the path 24 is generated. In the following description, a new diffracted sound passing through this path 24 is referred to as an additional diffracted sound.

  The structure shown in FIG. 11 provided with the hole 23 suppresses a peak at a frequency where L is a half λ and a dip at a frequency where L is a λ, which has been a problem in the conventional shape. The purpose is to flatten the pressure frequency characteristics.

  FIG. 12 is a graph showing the sign of relative pressure in the speaker device according to Embodiment 1 of the present invention. Specifically, in the same manner as in FIG. 4, the vertical axis represents the relative pressure and the horizontal axis represents the path length of the sound wave. A solid line 11 is diffracted from the direct sound 11 and a broken line 12 is diffracted from the back side of the baffle plate 22, and a diffracted sound 12 and a broken line 24 are diffracted from the back side of the baffle plate 22 through an arbitrary point 10 on the edge of the baffle plate 22. The additional diffracted sound 24 via the hole 23 is shown.

  The sign of the relative pressure when the path length is 0 indicates the sign of the relative pressure of the direct sound 11, the diffracted sound 12, and the additional diffracted sound 24 when the sound on the back and front of the speaker is generated. The relative pressure of the direct sound 11 and the relative pressure of the diffracted sound 12 and the relative pressure of the direct sound 11 and the relative pressure of the additional diffracted sound 24 are opposite to each other.

  The sign of the relative pressure 14 at the position where the path length of the direct sound 11 is R1, the sign of the relative pressure 15 at the position where the path length of the diffracted sound 12 is the sum of L and R2, and the additional diffracted sound 24 Each of the positive and negative signs of the relative pressure 25 at the position where the path length of L1 and R3 is the sum indicates the sign of the relative pressure at the listening point 13.

  Therefore, at the frequency where the sign of the relative pressure is the same, the sound pressure of the direct sound 11, the diffracted sound 12 and the additional diffracted sound 24 increases due to interference, and the sign of the relative pressure is reversed. The direct sound 11, the diffracted sound 12, and the additional diffracted sound 24 have a low sound pressure due to interference with each other.

  When the listening point 13 is sufficiently far from the front of the speaker 9 (for example, 20L <R1), it can be approximated as R1 = R2 = R3. Therefore, the path difference between the direct sound 11 and the diffracted sound 12 is L, and the path difference between the direct sound 11 and the additional diffracted sound 24 is L1.

  FIG. 13 is a graph of the sign of relative pressure in the speaker device according to the first embodiment of the present invention, and is a graph obtained by adding an additional diffracted sound 24 to FIG. More specifically, FIG. 8 is a graph obtained by adding the additional diffracted sound 24 to FIG. 8, which is an enlarged graph of the region 16 of FIG. 4, in the sign of the relative pressure at the frequency of the peak 18 in FIG. 6. .

  When L1 is short after the value of L1 becomes 1 / 2L, the sign of the relative pressure 15 of the diffracted sound 12 and the relative pressure 25 of the additional diffracted sound 24 is reversed, and when L1 is long The sign of the relative pressure 15 of the diffracted sound 12 and the relative pressure 25 of the additional diffracted sound 24 are the same.

  Furthermore, as L1 approaches 0, the proportion of the diffracted sound 12 and the additional diffracted sound 24 cancel each other increases. Conversely, as L1 approaches L, the proportion of the diffracted sound 12 and the additional diffracted sound 24 strengthens increases. .

The additional diffracted sound 24 is intended to cancel out the diffracted sound 12. For this reason, it can be said that the effect is positive as it cancels out, and the effect is negative as it strengthens. When the effect of the additional diffracted sound 24 on the peak 18 is ΔPa, the function indicating ΔPa is
ΔPa = Acos (πL1 / L)
Can be expressed as A is a weighting coefficient.

  Next, FIG. 14 is a graph of the sign of the relative pressure in the speaker device according to Embodiment 1 of the present invention, and is a graph obtained by adding an additional diffracted sound 24 to FIG. More specifically, FIG. 9 is a graph obtained by adding the additional diffracted sound 24 to FIG. 9, which is an enlarged graph of the region 16 in FIG. 4, of the positive / negative sign of the relative pressure at the frequency of the dip 19 in FIG. 6. .

  When L1 is longer than 1 / 4L and shorter than 3 / 4L between 1 / 4L and 3 / 4L, relative pressure 15 of diffracted sound 12 and relative pressure of additional diffracted sound 24 When the sign of 25 is opposite and shorter than 1 / 4L or longer than 3L, the sign of the relative pressure 15 of the diffracted sound 12 and the relative pressure 25 of the additional diffracted sound 24 is the same. .

  Furthermore, as L1 approaches 1 / 2L, the ratio of canceling out the diffracted sound 12 with the additional diffracted sound 24 increases, and conversely, as L1 approaches 0 or L, the diffracted sound 12 and the additional diffracted sound 24 become stronger. The proportion that fits increases.

The additional diffracted sound 24 is intended to cancel out the diffracted sound 12. For this reason, it can be said that the effect is positive as it cancels out, and the effect is negative as it strengthens. If the influence of the additional diffracted sound 24 on the dip 19 is ΔPb,
ΔPb = −Bcos (2πL1 / L)
Can be expressed as B is a weighting coefficient.

  FIG. 15 is a graph showing the effect of the additional diffracted sound 24 according to the first embodiment of the present invention. The vertical axis indicates the sum of ΔPa and ΔPb, and the horizontal axis indicates the length of L1. Here, the calculation was performed with the weighting coefficients A and B both set to 1.

  The sum of ΔPa and ΔPb is 0.5 or more when L1 is between 1 / 5L and 3 / 5L, and the effect of the additional diffracted sound 24 is expected to be great. Therefore, the position of the hole 23 of the baffle plate 22 is similar with the center of the speaker 9 being similar and drawn to be within the range of 5: 1 to 5: 3 with respect to the shape of the edge of the baffle plate 22. By providing a hole on the shape line, the peak 18 and the dip 19 of the sound pressure characteristic can be flattened.

  Furthermore, the sum of ΔPa and ΔPb is 1.0 or more when L1 is between 1/3 L and 1/2 L, and the effect of the additional diffracted sound 24 is expected to be even greater. Therefore, the position of the hole 23 of the baffle plate 22 is similar with the center of the speaker 9 being the center of similarity and drawn so as to be in the range of 3: 1 to 2: 1 with respect to the shape of the edge of the baffle plate 22. By providing a hole on the shape line, the peak 18 and the dip 19 of the sound pressure characteristic can be further flattened.

  As described above, according to the first embodiment, the baffle plate has a configuration capable of generating additional diffracted sound by providing a hole at a position away from the speaker by an appropriate distance. As a result, the problem of large peaks and dips in the sound pressure frequency characteristics at low frequencies can be avoided by the additional diffracted sound, and a speaker device having a desired flat sound pressure frequency characteristic can be realized. it can.

Embodiment 2. FIG.
In the first embodiment, by selecting L1 to a length between 1 / 5L and 3 / 5L, the sum of ΔPa and ΔPb becomes 0.5 or more, and the sound pressure frequency characteristic is flattened. I explained what I can do. On the other hand, in this Embodiment 2, the case where L1 is further limited and the sound pressure frequency characteristic is further flattened will be described.

  In the second embodiment, the effect of the additional diffracted sound 24, that is, in the frequency range where the sum of ΔPa and ΔPb is 1 or more and L is from 1/4 to 5/4 of the wavelength λ, Consider a case where a hole 23 is formed in the baffle plate 22 so that the sign of the relative pressure 14 of the diffracted sound 12 and the relative pressure 25 of the additional diffracted sound 24 is reversed, and L1 is 1 / 3L.

  FIG. 16 is a front view of the speaker device according to Embodiment 2 of the present invention. In FIG. 16, the shape of the edge of the baffle plate 27 is a perfect circle having a radius L with the speaker 9 as the center so that all the path lengths from the speaker 9 to the edge of the baffle plate 27 are equal to L. Further, a hole 29 is formed on the perfect circle 28 with a radius of 1/3 centered on the speaker 9 so that the width is 1 / 50L.

  FIG. 17 is a graph of sound pressure frequency characteristics when the speaker device of FIG. 16 according to Embodiment 2 of the present invention is used. The peak and dip on the sound pressure frequency characteristic are designated as peak 30, dip 31, and peak 32 in order from the lowest frequency. At a frequency lower than the peak 30, the sound pressure decreases as the frequency decreases.

  18 to 21 are positive / negative graphs of relative pressure in the speaker device according to the second embodiment of the present invention. Specifically, FIG. 18 is an enlarged graph of the region 26 in FIG. 12 among the graphs showing the relative pressure at the listening point 13 at a frequency lower than the frequency of the peak 30 in FIG. FIG. 19 is an enlarged graph of the region 26 in FIG. 12 among the graphs showing the relative pressure at the listening point 13 at the frequency of the peak 30 in FIG.

  FIG. 20 is an enlarged graph of the region 26 in FIG. 12 among the graphs showing the relative pressure at the listening point 13 at the frequency of the dip 31 in FIG. Further, FIG. 21 is a graph in which the region 26 in FIG. 12 is enlarged among the graphs showing the relative pressure at the listening point 13 at the frequency of the peak 32 in FIG.

  As shown in FIG. 18, at a low frequency where L is shorter than a quarter of the wavelength λ, the relative pressure 15 of the diffracted sound 12 and the relative pressure 25 of the additional diffracted sound 24 are both relative to the direct sound 11. The sign of the relative pressure is reversed with respect to the pressure 14. For this reason, the sound pressure is small.

  However, as shown in FIG. 19, at the frequency at which L is 1 / 2λ, the sign of the relative pressure 14 of the direct sound 11 and the relative pressure 15 of the diffracted sound 12 are equal, but the relative pressure 14 of the direct sound 11 is the same. The sign of the relative pressure 25 of the additional diffracted sound 24 is reversed. For this reason, compared with the case where there is no additional diffracted sound 24, the sound pressure of the peak 30 becomes low.

  Further, as shown in FIG. 20, at the frequency where L is equal to the wavelength λ, the sign of the relative pressure 14 of the direct sound 11 and the relative pressure 15 of the diffracted sound 12 are opposite, and the relative pressure 14 of the direct sound 11 The sign of the relative pressure 25 of the additional diffracted sound 24 is equal. For this reason, compared with the case where there is no additional diffracted sound 24, the sound pressure of the dip 31 becomes high.

  As shown in FIG. 21, at the frequency where L is 3 / 2λ, the relative pressure 15 of the diffracted sound 12 and the relative pressure 25 of the additional diffracted sound 24 are both positive and negative with respect to the relative pressure 14 of the direct sound 11. Will be equal. For this reason, the sound pressure of the peak 32 becomes high.

  As a result, the maximum sound pressure difference 33 is 6.5 dB, and the frequency characteristic is flattened by 3.5 dB compared to the maximum sound pressure difference 10 dB when there is no additional diffracted sound 24.

  In addition, the hole 29 of the baffle plate 27 shown in FIG. For this reason, the baffle plate 27 and the speaker 9 inside the hole 29 are in a floating shape. However, in actual use, it is conceivable to indicate the inside so that the holes 29 are not continuous.

  FIG. 22 is a front view of a speaker device having a configuration different from FIG. 16 in the second embodiment of the present invention. As shown in FIG. 22, the holes 34 are not continuous. The inner side is supported by a support 35 or a wire, and even if such a configuration is adopted, the same effect as the configuration of FIG. 16 can be obtained.

  As described above, according to the second embodiment, the position on the circumference away from the speaker by an appropriate distance so as to enhance the effect of the additional diffracted sound relative to the baffle plate as compared with the first embodiment. A configuration is provided in which an additional diffracted sound can be generated by providing a hole. As a result, the problem that a large peak and dip occur in the sound pressure frequency characteristic at a low frequency can be avoided by the additional diffracted sound, and a desired sound that is further flattened than in the first embodiment. A speaker device having pressure frequency characteristics can be realized.

Embodiment 3 FIG.
In the second embodiment, the case where the holes 29 formed on the circumference of the perfect circle 28 are provided on the baffle plate 27 whose edge shape is a perfect circle has been described. On the other hand, in the third embodiment, a case will be described in which flattening of sound pressure frequency characteristics is realized by providing a hole in a conventional square baffle plate.

  FIG. 23 is a front view of a conventional speaker device provided with a square baffle plate 36. FIG. 24 is a graph of the sound pressure frequency characteristics of the conventional speaker device shown in FIG. As shown in FIG. 24, the conventional speaker device has a maximum sound pressure difference 37 of 9 dB.

  On the other hand, FIG. 25 is a front view of the speaker device including the baffle plate 38 according to Embodiment 3 of the present invention. As shown in FIG. 25, the baffle plate 38 according to the third embodiment has a similar shape 39 drawn with the center of the speaker 9 as the center of similarity and the similarity ratio with the edge of the baffle plate 38 being 3: 1. Is a center line, and a hole 40 having a width of 1/50 L is formed.

  FIG. 26 is a graph of sound pressure frequency characteristics when the baffle plate 38 shown in FIG. 25 is used in the speaker device according to Embodiment 3 of the present invention. As shown in FIG. 26, by using the baffle plate 38, the maximum sound pressure difference 41 becomes 6 dB, and the frequency characteristic is flattened by 3 dB rather than the maximum sound pressure difference 9 dB when there is no additional diffracted sound 24. Yes.

  As described above, according to the third embodiment, the same square baffle plate as that of the prior art is provided with a configuration capable of generating additional diffracted sound by providing a hole having a similar shape as a center line. . As a result, as in the first and second embodiments, the problem that a large peak and dip occur in the sound pressure frequency characteristic at a low frequency can be avoided by the additional diffracted sound, and the flattened desired Thus, a speaker device having the sound pressure frequency characteristics can be realized.

Embodiment 4 FIG.
In the second embodiment described above, the case where the holes 29 formed in the entire circumference on the circumference of the perfect circle 28 are provided in the baffle plate 27 whose edge shape is a perfect circle has been described. On the other hand, in the fourth embodiment, a case where a hole is provided in a part of the entire circumference will be described.

  FIG. 27 is a front view of the speaker device according to Embodiment 4 of the present invention. As shown in FIG. 27, the baffle plate 42 is partially formed with holes 43 divided into two places, with half the circumference as a hole.

  FIG. 28 is a graph of sound pressure frequency characteristics when the speaker device of FIG. 27 in the fourth embodiment of the present invention is used. As shown in FIG. 28, the maximum sound pressure difference 44 is 9 dB, and the frequency characteristic is flattened by 1 dB compared to the maximum sound pressure difference 10 dB when there is no additional diffracted sound 24.

  FIG. 29 is a front view of a speaker device different from FIG. 27 in the fourth embodiment of the present invention. As shown in FIG. 29, holes 46 divided into four locations are partially formed on the baffle plate 45 with half the circumference as a hole.

  FIG. 30 is a graph of sound pressure frequency characteristics when the speaker device of FIG. 29 according to Embodiment 4 of the present invention is used. As shown in FIG. 30, the maximum sound pressure difference 47 is 9 dB, and the frequency characteristic is flattened by 1 dB compared to the maximum sound pressure difference 10 dB when there is no additional diffracted sound 24.

  As described above, according to the fourth embodiment, the baffle plate has a configuration capable of generating additional diffracted sound by providing a hole in a part of the circumference that is separated from the speaker by an appropriate distance. . As a result, the problem that a large peak and dip occur in the sound pressure frequency characteristic at a low frequency can be avoided by the additional diffracted sound, as in the second embodiment in which holes are provided all around the circumference. A speaker device having a flattened desired sound pressure frequency characteristic can be realized.

Embodiment 5. FIG.
In the second embodiment, the case where the width of the hole provided on the entire circumference is set to 1/50 L has been described. On the other hand, in the fifth embodiment, the hole width is changed to various values, and the effect of suppressing the maximum sound pressure difference is verified.

  FIG. 31 is a front view of the speaker device according to Embodiment 5 of the present invention. As shown in FIG. 31, the baffle plate 48 in the fifth embodiment is provided with a hole 49 having a width X. And in this Embodiment 5, when making X into 5 types of 1 / 100L, 1 / 200L, 1 / 40L, 1 / 30L, and 1 / 15L, each maximum sound pressure difference is shown. Looking for.

  FIG. 32 is a graph of the sound pressure frequency characteristics when the baffle plate 48 having a width X of 1/100 L in the fifth embodiment of the present invention is used. As shown in FIG. 32, the maximum sound pressure difference 50 was 7.5 dB, and the flattening effect was 2.5 dB.

  FIG. 33 is a graph of the sound pressure frequency characteristics when using the baffle plate 48 with the width X set to 1 / 200L in the fifth embodiment of the present invention. As shown in FIG. 33, the maximum sound pressure difference 51 was 9 dB, and the flattening effect was 1 dB.

  FIG. 34 is a graph of sound pressure frequency characteristics when the baffle plate 48 having a width X of 1 / 40L in the fifth embodiment of the present invention is used. As shown in FIG. 34, the maximum sound pressure difference 52 was 6 dB, and the flattening effect was 4 dB.

  FIG. 35 is a graph of sound pressure frequency characteristics when the baffle plate 48 having a width X of 1/30 L in the fifth embodiment of the present invention is used. As shown in FIG. 35, the maximum sound pressure difference 55 was 6 dB, and the flattening effect was 4 dB.

  However, when the width of the hole 29 is 1/30 L, the peak 54 has a higher relative sound pressure than the peak 53 as shown in FIG. This is not preferable because it indicates that the relative sound pressure of the first peak 53 is lowered excessively from a low frequency.

  FIG. 36 is a graph of sound pressure frequency characteristics when the baffle plate 48 having a width X of 1/15 L is used in the fifth embodiment of the present invention. As shown in FIG. 36, the maximum sound pressure difference 58 was 6 dB, and the flattening effect was 4 dB.

  However, when the width of the hole 29 is 1/15 L, as shown in FIG. 36, the peak 57 has a relative sound pressure higher than that of the peak 56 as in the case where the width of the hole 29 is 1/30 L. It is high. This is not preferable because it indicates that the relative sound pressure of the first peak 56 is excessively lowered from a low frequency.

  FIG. 37 is a graph showing the relationship between the flattening amount and the hole width in the fifth embodiment of the present invention. The vertical axis represents the flattening amount, and the horizontal axis represents the hole width, and the results of FIGS. 17 and 32 to 36 are summarized. As shown in FIG. 37, when the width of the hole 49 is larger than 1/100 L, a flattening effect of 2 bB or more is obtained.

  However, a hole width larger than 1/30 L is not preferable because the relative sound pressure of the first peak is excessively lowered as described above. Accordingly, it can be considered that the effect of flattening the frequency characteristic by the additional diffracted sound 24 is obtained when the width of the hole is in a range between 1/100 L and 1/40 L.

  As described above, according to the fifth embodiment, by setting the width of the hole of the baffle plate in a range from 1/100 L to 1/40 L, there is a large peak and dip in the sound pressure frequency characteristics at a low frequency. The problem of occurrence can be avoided by the additional diffracted sound, and a speaker device having a flattened desired sound pressure frequency characteristic can be realized.

Embodiment 6 FIG.
In the first to fifth embodiments, the case where the speaker 9 is arranged at the center of the baffle plate has been described. However, the position of the speaker 9 is not necessarily the center of the baffle plate, and a specific example will be described.

  FIG. 38 is a front view of the speaker device according to Embodiment 6 of the present invention. As shown in FIG. 38, the speaker 9 may be provided on the upper part of the rectangular parallelepiped baffle plate 59, and the position of the hole 60 may be determined from L and L 'with the position of the speaker 9 as the center of similarity. That is, in FIG. 38, the hole 60 has a similar shape drawn with a similar ratio of 3: 1 with respect to the shape of the edge of the baffle plate 59 with the center of the speaker 9 determined from L and L ′ as the center of similarity. Is determined.

  FIG. 39 is a front view of a speaker device different from FIG. 38 in the sixth embodiment of the present invention. Also in the baffle plate 61 having a distorted shape as shown in FIG. 39, the hole 62 can be determined with the position of the speaker 9 as the center of similarity. That is, in FIG. 39, the position of the hole 62 is determined by the similar shape drawn with the similarity ratio of 3: 1 with respect to the shape of the edge of the baffle plate 61 with the center of the speaker 9 determined from L as the center of similarity. It is determined.

  As described above, according to the sixth embodiment, additional diffracted sound can be obtained by providing a hole having a certain similarity ratio with the position of the speaker as the center of similarity on baffle plates having various outer diameter shapes. It has a configuration that can generate. As a result, as in the first to fifth embodiments, the problem that a large peak and dip occur in the sound pressure frequency characteristic at a low frequency can be avoided by the additional diffracted sound, and the flattened desired Thus, a speaker device having the sound pressure frequency characteristics can be realized.

Embodiment 7 FIG.
In the seventh embodiment, the case where the position of the hole is rotated or reversed will be described. FIG. 40 is a front view of the speaker device according to Embodiment 7 of the present invention. If the sound radiated from the speaker 9 is axisymmetric with respect to the central axis of the diaphragm of the speaker 9, the hole 64 opened in the perforated baffle plate 22 is centered on the center of the speaker 9 as shown in FIG. There is no problem even if it is rotated as. Further, there is no problem even if the hole 64 is reversed with respect to a line segment passing through the center of the speaker 9.

  However, in the case of rotation, the axis of rotation should be the same as the central axis of the diaphragm of the speaker 9, and in the case of inversion, the axis of inversion exists in the plane of the baffle plate 63 and the speaker 9 It must intersect with the central axis of the diaphragm. Further, the hole 64 needs not to go outside the edge of the baffle plate 63.

  As described above, according to the seventh embodiment, the problem that a large peak and dip occur in the sound pressure frequency characteristic at a low frequency even when the hole formed in the baffle plate is rotated or reversed is added diffraction. A speaker device that can be avoided by sound and has a flattened desired sound pressure frequency characteristic can be realized.

  1 Diaphragm, 2 Bobbin, 3 Voice coil, 4 Roll edge, 5 Frame, 6 Magnetic field, 7 Permanent magnet, 8 Baffle plate, 9 Speaker, Arbitrary point, 11 Direct sound path, 12 Diffracted sound path , 13 Listening point, 14 Relative pressure of direct sound, 15 Relative pressure of diffracted sound, 16 Area indicating the path difference between direct sound and diffracted sound, 17 Baffle plate, 18 peak, 19 dip, 20 peak, 21 Sound pressure difference, 22 Perforated baffle plate, 23 holes, 24 Additional diffracted sound path, 25 Relative pressure of additional diffracted sound, 26 Area showing direct sound, diffracted sound and additional diffracted sound path difference, 27 Perforated baffle board, 28 Edge similarity Shape, 29 holes, 30 peaks, 31 dip, 32 peaks, 33 sound pressure difference, 34 holes, 35 support, 36 baffle plate, 37 sound pressure difference, 38 hole baffle plate, 39 Similar shape of edge, 40 holes, 41 sound pressure difference, 42 hole perforated baffle plate, 43 holes, 44 sound pressure difference, 45 hole perforated baffle plate, 46 holes, 47 sound pressure difference, 48 hole perforated baffle plate, 49 holes, 50 sound Pressure difference, 51 sound pressure difference, 52 sound pressure difference, 53 peak, 54 peak, 55 sound pressure difference, 56 peak, 57 peak, 58 sound pressure difference, 59 perforated baffle plate, 60 holes, 61 perforated baffle plate, 62 holes, 63 hole Perforated baffle plate, 64 holes.

Claims (4)

A speaker having a diaphragm that emits sound by vibration;
A baffle plate arranged all around the speaker, and a speaker device arranged so that a central axis of the speaker diaphragm and a normal direction of the baffle plate are parallel to each other,
The baffle plate has a hole therethrough,
The hole is
On the line of the first figure which is a similar shape drawn so that the center of the speaker is the center of similarity and the similarity ratio is in the range of 5: 1 to 5: 3 with respect to the shape of the edge of the baffle plate,
Alternatively, on the line of the second graphic obtained by rotating the first graphic about the center of the speaker as an axis,
Alternatively, the speaker device is formed on one of the lines of the third graphic obtained by inverting the first graphic with respect to a line segment passing through the center of the speaker. The first figure is a similar shape drawn so that a center of the speaker is a similar center and a range of a similarity ratio of 3: 1 to 2: 1 with respect to an edge shape of the baffle plate. 2. The speaker device according to 1. The width | variety on the said line is formed so that the width on the said line may become the range of 1/100 to 1/40 of the distance from the center of the said speaker to the edge of the said baffle board. Speaker device. A speaker having a diaphragm that emits sound by vibration;
A baffle plate disposed around the entire circumference of the speaker, and a speaker device manufacturing method in which a central axis of the diaphragm of the speaker and a normal direction of the baffle plate are parallel to each other,
A similar shape drawn with the center of the speaker as the center of similarity with respect to the baffle plate so as to be in a range of a similarity ratio of 5: 1 to 5: 3 with respect to the shape of the edge of the baffle plate. On the shape line,
Alternatively, on the line of the second graphic obtained by rotating the first graphic about the center of the speaker as an axis,
Alternatively, a speaker device having a step of forming a through-hole over a part or all of the circumference of a line on a line of a third figure obtained by inverting the first figure with respect to a line segment passing through the center of the speaker. Production method.

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