JP2007180980A - Reflection type electroacoustic transducer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it possible to listen to sound of constant sound pressure within the area of a reflection type electroacoustic transducer and listen to sound of constant sound quality within the area and to prevent the volume and sound quality of the sound to be listened to from changing even if a listener moves in the reflection type electroacoustic transducer for providing sound of high sound pressure to a particular area. <P>SOLUTION: The reflection type electroacoustic transducer (500) is provided with an electroacoustic transducer (150) having a polyhedral diaphragm (200) obtained by connecting a plurality of diaphragms (10) having an external shape of a polygon with a flexible connection member (102) to be a polyhedral shape and a driving part (232) for vibrating the polyhedral diaphragm (200), and a bowl-shaped reflection plate (520), wherein the electroacoustic transducer (150) is arranged at a position facing an inner surface (520a) of the reflection plate (520). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a reflection-type electroacoustic transducer including an electroacoustic transducer and a reflector that reflects sound output from the electroacoustic transducer.

In recent years, personalization of electronic devices has been proceeding with great speed.
As a result, even in PA (Public Address), there is a strong desire to transmit the reproduced sound of an electroacoustic transducer (hereinafter also simply referred to as a speaker) only to a specific range or to a specific person. ing.
In order to achieve this, various narrow directional speakers (hereinafter also simply referred to as directional speakers) that emit sound with a large sound pressure in a specific direction have been proposed in the past. There is a speaker.

As another example, a speaker has been proposed in which not only directivity but also frequency characteristics are focused, and a change in sound pressure frequency characteristics is reduced over a wide frequency range while obtaining narrow directivity. Has been.
For example, when the directional speaker described in Patent Document 2 is installed in a room, the sound from the speaker can be heard only under the speaker without dividing the room.
Therefore, for example, in an exhibition hall, visitors can listen to the explanation of the exhibits without using an earphone or the like by standing in the area immediately before each exhibit, and can make a plurality of differences in one room. Even when the contents are broadcast at the same time, the visitor can hear only the target sound clearly by standing at each predetermined position.

A directional speaker as described in each of the above-mentioned patent documents uses a reflective directional plate having a reflective surface formed of a rotating paraboloid or a spheroid surface, and reflects the sound emitted from the speaker to the reflective directional plate. By doing so, it is configured to obtain a predetermined directivity.
Japanese Patent Laid-Open No. 2-87797 JP-A-5-207584

By the way, in the conventional directional speaker, the diaphragm of the speaker as a sound radiation source has a so-called cone shape or flat plate shape, and the directivity characteristic that is a radiation pattern of the sound generated by such a speaker is generally shown in FIG. As shown, it is not constant in the 360 ° azimuth but has a distorted characteristic.
Specifically, the sound pressure decreases as it goes from 0 ° (front of the speaker) in FIG. 28 toward ± 90 ° (90 ° and 270 ° in FIG. 28). Further, the characteristic varies depending on the frequency, and the sound pressure decreases more markedly as the sound becomes higher.

Therefore, for example, in the case of the speaker of Patent Document 1, the sound J5 emitted from the speaker J2 at a large angle with respect to the vibration axis 0 ° is emitted at a small angle, as illustrated in FIG. The sound pressure is lower than that of the reproduced sound J15, and the sound pressure drop in the high sound range is remarkable.
Accordingly, the same applies to the sounds J6 and J60 in which the sounds J15 and J5 are reflected by the reflector J1, respectively, and the vibration J6 reaches the listener L1 on the vibration axis 0 ° or close to the vibration axis 0 °. The sound pressure of the sound J60 that reaches the listeners L2 and L3 away from the axis 0 ° is low, and the sound is different from the original sound in which the high sound range is attenuated.
That is, there is a problem that the sound received by the directional speaker within a predetermined listening area is not constant in sound volume and has a different sound quality.

  Therefore, when the listener moves within the area, the sound hearing changes, and the listening position where the sound can be heard in the best state, that is, the highest volume, and the high sound can be heard well, is generally pinpointed. Therefore, there is a problem that the listener has to find the best listening position while moving within the area.

  Therefore, the problem to be solved by the present invention is that even a reflection type electroacoustic transducer that includes a reflecting member and provides high sound pressure sound in a specific area has a sound pressure that is constant within that area. It is intended to provide a reflective electroacoustic transducer that can listen to sound, can receive sound of a certain sound quality within the region, and does not change the sound volume or sound quality of the sound that is heard even if the listener moves. .

In order to solve the above problems, the present invention has the following configurations [1] to [6] as means.
[1] A polyhedral diaphragm (200, 201) having a polyhedral shape by connecting a plurality of diaphragms (10, 100) having a polygonal outer shape with a flexible connecting member (102), and the polyhedral diaphragm ( 200, 201), an electroacoustic transducer (150) having a drive unit (232) for vibrating, and a bowl-shaped reflector (520),
The electroacoustic transducer (150) is a reflective electroacoustic transducer (500), which is disposed at a position facing the inner surface (520a) of the reflector (520).
[2] The inner surface (520a) of the reflecting plate (520) is a part of a paraboloid of revolution or a part of the surface of a spheroid, and the electroacoustic transducer (150) The reflective electroacoustic transducer (500) according to [1], which is arranged on the symmetry axis (CL) of 520a).
[3] A rotating means (521) for rotating the electroacoustic transducer (500) and the reflector (520) about a predetermined axis (RC) is provided [1] or The reflective electroacoustic transducer (500A) according to [2].
[4] An axial movement means (570) for moving the electroacoustic transducer (150) in the contact / separation direction with respect to the reflector (520) is provided [1] to [3] It is a reflection type electroacoustic transducer (500C) in any one of.
[5] Each of the plurality of diaphragms (10, 100) includes a plurality of drive units (232) that vibrate each of the diaphragms (10, 100), and is independent of each of the plurality of drive units (232). The reflective electroacoustic transducer (500B) according to any one of [1] to [4], further comprising a signal output means (551) for outputting a signal.
[6] Sound detection means (552) for detecting sound from the electroacoustic transducer (150),
The signal output means (551)
A signal generation unit (551e) that generates a predetermined reference signal (SG3) and causes the electroacoustic transducer (150) to output the generated reference signal (SG3);
Based on the sound of the reference signal (SG3) output from the electroacoustic transducer (150) and detected by the sound detection means (552), a sound signal (to be reproduced by the electroacoustic transducer (150)) The reflection type electroacoustic transducer according to [5], further comprising: a delay processing unit (551c) that delays and outputs SGIN) independently to each of the plurality of driving units (232). 500B).

  According to the present invention, the sound from the electroacoustic transducer is reflected by the reflecting member to provide a sound with a high sound pressure in a specific area, and a sound with a constant sound pressure can be heard in the area. It is possible to obtain a sound with a certain sound quality within the region, and even if the listener moves within the region, the volume and sound quality of the sound to be heard do not change.

The preferred embodiments of the present invention will be described with reference to FIGS.
FIG. 1 is a perspective view showing a reflective electroacoustic transducer according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view illustrating a reflective electroacoustic transducer according to an embodiment of the present invention.
FIG. 3 is a schematic perspective view showing elements of a diaphragm applied to the present invention.
FIG. 4 is a plan view and a cross-sectional view showing elements of the diaphragm applied to the present invention.
FIG. 5 is a cross-sectional view showing an electroacoustic transducer using a diaphragm element applied to the present invention.
FIG. 6 is a cross-sectional view showing another example of the electroacoustic transducer using the diaphragm element applied to the present invention.
FIG. 7 is a schematic diagram for explaining a standing wave distribution in a conventional diaphragm.
FIG. 8 is a schematic diagram for explaining the standing wave distribution in the elements of the diaphragm applied to the present invention.
FIG. 9 is a graph showing frequency-sound pressure characteristics according to the amount of eccentricity of the diaphragm.
FIG. 10 is a schematic cross-sectional view for explaining the shape of the element of the diaphragm applied to the present invention.
FIG. 11 is a schematic cross-sectional view for explaining another shape of the element of the diaphragm applied to the present invention.
12A and 12B are a plan view and a cross-sectional view showing another shape of the element of the diaphragm applied to the present invention.
FIG. 13 is a front view for comparing and explaining the shape of a conventional diaphragm and other shapes of diaphragm elements applied to the present invention.
FIG. 14 is a schematic cross-sectional view for explaining an electroacoustic transducer using another shape of the diaphragm element applied to the present invention.
FIG. 15 is a development view for explaining the diaphragm used in the embodiment of the present invention.
FIG. 16 is an external view showing an electroacoustic transducer used in an embodiment of the present invention.
FIG. 17 is a perspective view for explaining the structure of the electroacoustic transducer used in the embodiment of the present invention.
FIG. 18 is a partial cross-sectional view for explaining the structure of the electroacoustic transducer used in the embodiment of the present invention.
FIG. 19 is another perspective view for explaining the structure of the electroacoustic transducer used in the embodiment of the present invention.
FIG. 20 is a front view and a perspective view for explaining a modification of the diaphragm used in the embodiment of the present invention.
FIG. 21 is a front view for explaining the electroacoustic transducer used in the embodiment of the present invention.
FIG. 22 is a diagram showing the directivity characteristics of the electroacoustic transducer used in the example of the present invention.
FIG. 23 is a cross-sectional view illustrating the operation of the reflective electroacoustic transducer according to the embodiment of the present invention.
FIG. 24 is a schematic diagram for explaining a reflective electroacoustic transducer according to a second embodiment of the present invention.
FIG. 25 is another schematic diagram for explaining the reflection type electroacoustic transducer of the second embodiment of the present invention.
FIG. 26 is a block diagram for explaining a reflective electroacoustic transducer according to a third embodiment of the present invention.
FIG. 27 is a schematic cross-sectional view illustrating a reflective electroacoustic transducer according to a fourth embodiment of the present invention.
In the following description, “rotation symmetry” means at least two or more rotation symmetry.

<First embodiment>
A first embodiment of the electroacoustic transducer of the present invention will be described in detail.
As shown in FIG. 1, the electroacoustic transducer 500 includes a substantially spherical electroacoustic transducer 150 and a bowl-shaped reflector 520. Hereinafter, the electroacoustic transducer 500 is referred to as a reflective directional speaker for convenience.

As shown in FIG. 2, the reflector 520 has, for example, a bowl-like shape having a part of a rotating paraboloid formed around the axis CL or a part of the surface of a spheroid as an inner surface 520a. Is formed.
In addition, a hole 520b is provided at a portion of the reflecting plate 520 that intersects the axis CL.

The electroacoustic transducer 150 is a diaphragm 200 having a substantially spherical shell formed by combining a plurality of regular pentagonal diaphragms 10 so as to be positioned on each face of a regular dodecahedron (hereinafter, for distinction from individual diaphragms). And a driving unit 232 (not shown) which is disposed in the spherical shell 200, and a base 130 (not shown) which supports the driving unit 232. Further, one end side is coupled to the drive unit 232, and a support leg 103 extending to the outside of the spherical shell diaphragm 200 is provided.
The support leg 103 is fixed to the hole 520b of the reflection plate 520 on the other end 103a side, and the end 103a is screwed with a desired attachment member, leg, or the like according to the installation state of the reflective directional speaker 500. The fixing part is formed with a male screw so that it can be fixed.

Next, the reflective directional speaker 500 will be described in detail.
First, the substantially spherical electroacoustic transducer 150 will be described.

<First Example of Diaphragm>
The shape of the first embodiment of the diaphragm that is a constituent element of the spherical shell diaphragm used in the reflective directional speaker 500 of the embodiment will be described with reference to FIGS. FIG. 3 shows a plurality of radial solid lines 16 schematically showing the curvature so that the curved surface shape of the diaphragm can be easily understood.
3 is a perspective view showing the appearance of the diaphragm 10, FIG. 4A is a plan view showing the diaphragm 10, and FIG. 4B is a view of S1-S1 in FIG. 4A. It is sectional drawing.

As shown in FIGS. 3 and 4, the diaphragm 10 includes a central portion 11 ranging from a central axis O to an inner diameter portion 13 having a diameter D1 [see FIG. 4A], and an inner diameter portion 13 to a diameter D2. [Refer to FIG. 4 (a)] It is formed in a substantially disk shape formed by the inclined portion 12 that is a range up to the outer diameter portion 14.
The material of the diaphragm is not particularly limited, and paper, resin such as PP (polypropylene), metal such as aluminum, ceramics, or wooden sheets can be used.

The inner diameter portion 13 is formed so as to protrude by a maximum height h1 (see FIG. 4B) with respect to the reference plane P0 including the outer diameter portion 14, and the center portion 11 inside thereof is the most protruding portion. The curved surface is recessed by a depth h2 (see FIG. 4B) with respect to a certain inner diameter portion 13.
Accordingly, the inner diameter portion 13 forms a circular ridge line having a diameter D1.
The inclined portion 12 is formed as a surface connecting the inner diameter portion 13 and the outer diameter portion 14.
Further, an intermediate diameter portion 15 (indicated by a two-dot chain line) having a diameter D3 is formed between the inner diameter portion 13 and the outer diameter portion 14. The intermediate diameter portion 15 is a portion (inflection portion) where the curvature of the surface of the inclined portion 12 changes significantly.

The diaphragm 10 will be described in more detail. The surface of the region on the inner side (center axis O side) of the inclined portion 12 (hereinafter, referred to as the inclined portion inner side surface 12a) has a curvature in the concave direction. As a curved surface, a surface (hereinafter referred to as an inclined portion outer surface 12b) outside the intermediate diameter portion 15 (opposite to the central axis O) is formed as a flat surface having no curvature. .
The intermediate diameter portion 15 has a central axis O2 that is eccentric with respect to the central axis O of the inner diameter portion 13 and the outer diameter portion 14 by a distance α (an eccentric amount α).
Therefore, the intermediate diameter portion 15 is a region where the curvature is discontinuous between the eccentric center axis O2 side surface (inclined portion inner surface 12a) and the opposite surface (inclined portion outer surface 12b) with this as a boundary. And shown as a line that goes around the eccentric central axis O2.

  Further, the curvature R of the inner surface 12a of the inclined portion is not constant, but continuously changes from the maximum Rmax to the minimum Rmin (see FIG. 4B) in the circumferential direction, and is based on the changing curvature R and the eccentric distance α. Thus, the inclined portion inner side surface 12a is formed.

Next, the electroacoustic transducer 50 using the diaphragm 10 described above will be described.
The electroacoustic transducer 50 is also referred to as a speaker unit. For example, as shown in FIG. 5, the diaphragm 10 and a flexible edge 30 connected to the outer diameter portion 14 side of the diaphragm 10, The housing 31 includes an edge 30 fixed thereto, and a magnetic circuit 34 that is fixed to the housing 31 and drives the diaphragm 10.

The magnetic circuit 34 includes a cup-shaped yoke 23 having a bottom portion 23 and an annular wall portion 23b, a magnet 24 fixed to the inner surface of the bottom portion 23a, and a cylindrical pole piece 25 fixed to the magnet 24. Composed. As the edge 30, for example, a rubber material or a resin material can be used.
In addition, a voice coil bobbin 21 and a voice coil 22 wound around the outer peripheral surface on one end side thereof are inserted in a gap between the annular wall portion 23b of the yoke 23 and the pole piece 25. The voice coil 22 is supplied with electricity from the outside through a lead wire 22 a, and the lead wire 22 a is drawn out from a hole 31 a provided in the housing 31.
Further, the voice coil bobbin 21 is connected to a housing 31 by a damper 33 whose outer peripheral surface is elastic, and can freely vibrate in a direction (vibration direction) parallel to the central axis O of the diaphragm 10 via the damper 33. It is supported by.
The drive unit 32 includes the magnetic circuit 34, the voice coil bobbin 21, and the voice coil 22.

  Although a part of the vibration plate 10 will be described in detail, the diaphragm 10 has a flexible annular edge 30 fixed in the vicinity of the outer diameter portion 14, and the outer peripheral portion of the edge 30 is an annular shape of the housing 31. It is fixed to the frame 31b. At the time of fixing, the diaphragm 10 is attached in such a direction that the inner diameter portion 13 protrudes on the side opposite to the drive portion 32.

One end of a circular voice coil bobbin 21 is fixed to the surface opposite to the protruding direction of the inner diameter portion 13 protruding in a circular ridge shape.
A voice coil 22 is wound around the outer peripheral surface of the voice coil bobbin 21 on the other end side.
The cup-shaped yoke 23 is disposed such that its inner wall surface 23a faces the voice coil 22 with a predetermined magnetic gap.

On the other hand, inside the portion of the voice coil bobbin 21 around which the voice coil 22 is wound, the outer peripheral surface of the disc-shaped pole piece 25 connected to the cylindrical magnet 24 has a predetermined gap with the inner surface of the voice coil bobbin 21. And are arranged so as to face each other.
The voice coil bobbin 21 is supported by a frame 31 through a damper 33 so as to be movable in the vibration direction.

  As the edge 30, the frame 31, and the drive unit 32 used in the electroacoustic transducer 50 described above, general-purpose components whose outer shape is not eccentric with respect to the central axis O can be used as they are, and dedicated components for the diaphragm 10 are used. Since it is not necessary to use the cost, an increase in cost can be suppressed.

The direction in which the inner diameter portion 13 of the diaphragm 10 protrudes with respect to the drive unit 32 may be directed to the drive unit 32 side opposite to the direction of FIG. 5 described above. That is, it is a form in which the inner diameter portion 13 is depressed, and this example is shown in FIG.
The electroacoustic transducer 50A shown in FIG. 6 is such that the protruding direction of the diaphragm 10 is opposite to the electroacoustic transducer 50 shown in FIG. 5, and one end side of the voice coil bobbin 21 is connected to the inner diameter portion 13 of the diaphragm 10. It is fixed to the surface on the protruding side. The rest is the same as the electroacoustic transducer 50.
Therefore, the voice coil bobbin 21 having a shorter length in the central axis O direction than that used for the electroacoustic transducer 50 can be used.

The electroacoustic transducer 50 with the inner diameter portion 13 projecting outward as shown in FIG. 5 has a wider directivity than the electroacoustic transducer 50A with the inner diameter portion 13 depressed inward as shown in FIG. In particular, it is suitable for an electroacoustic transducer (so-called tweeter) that outputs a high-frequency range sound that is difficult to obtain a wide directivity.
Further, the electroacoustic transducer 50A in which the inner diameter portion 13 is recessed inside is suitable for a large-diameter electroacoustic transducer (so-called woofer) for a low frequency range because the diaphragm 10 does not protrude outward.

  Next, when the diaphragm 10 having the central axis O2 eccentric with respect to the central axis O of the outer diameter portion 14 is used as described above, and the central axis O2 of the intermediate diameter portion 15 is A comparison of characteristics and the like in the case of using a diaphragm that is not eccentric will be described below.

7 and 8 respectively show a diaphragm 10a (comparative example) when the center axis O2 of the intermediate diameter portion 15 is not eccentric with respect to the center axis O, and a first axis having the center axis O2 where the intermediate diameter portion 15 is eccentric. The mode of the vibration of the diaphragm about the diaphragm 10 of 1 form is shown.
7 and 8, as a vibration analysis condition, a force obtained from the effective coil length and the number of turns of the voice coil 22 under the magnetic field strength of the actual magnetic circuit 34 is applied to the voice coil 22 as a sine vibration. The distribution of standing waves in the AA cross section in the direction of the central axis O of each diaphragm when the vibration is 12 kHz is shown.

In these drawings, the upper diagram is a plan view of the diaphragm, and the amount of vibration displacement is shown on the lower side corresponding to this.
Specifically, in the diagram of the amount of displacement on the lower side, the broken line indicates the cross-sectional shape of the diaphragm, and the solid line indicates the standing wave distribution. This displacement is exaggerated.
From the comparison of each figure, it can be seen that the standing wave is clearly asymmetric with respect to the central axis O when the diaphragm 10 of the first embodiment is used. Further, the number of peaks that are remarkably generated with respect to the central axis O is also different.

9 shows a diaphragm 10a as a comparative example shown in FIG. 7 in which the central axis O2 of the intermediate diameter portion 15 and the central axis O coincide (that is, the eccentric amount is 0.0 mm), and the central axis of the intermediate diameter portion 15. The frequency-sound pressure characteristics in electroacoustic transducers using two examples of diaphragm 10 in which O2 is decentered by 1.5 mm and 3.0 mm as an eccentric amount α from central axis O are shown.
FIG. 8 shows a diaphragm 10a as a comparative example in which the center O2 of the intermediate diameter portion 15 is 0.0 mm (no eccentricity) from the center axis O, and the center O2 of the intermediate diameter portion 15 is 1.5 mm from the center axis O. 2 shows frequency-sound pressure characteristics in electroacoustic transducers using two types of diaphragms 10 that are eccentric by 3.0 mm.

When the diaphragm 10a which is a comparative example is used, a deep dip is seen in the vicinity of 8 kHz (see arrow). However, when there is an eccentricity as in the two examples, the dip is filled as the amount increases. It turns out that it flattens more.
It can also be seen that the other peaks and dips become gentler by decentering, and become smoother as the decentering amount α increases.

By the way, the inclined portion inner side surface 12a between the inner diameter portion 13 and the intermediate diameter portion 15 is, for example, a curved surface having a cross-sectional shape in a plane passing through the central axis O as shown in FIGS. May be. [FIGS. 10A to 10C are schematic views showing a case where the intermediate diameter portion 15 has a central axis O2 eccentric to the left in the figure with respect to the central axis O of the outer diameter portion 14. FIG. Yes. ]
Specifically, FIGS. 10A and 10C are examples in which the inclined portion inner side surface 12a is an inclined curved surface having such a curvature that it is recessed inward in this cross-sectional shape.
Further, FIG. 10B shows that the inclined inner surface 12a is an inclined curved surface having a curvature such that the inner diameter portion 13 side is recessed inward in the sectional shape, while the outer diameter portion 15 side is curved in the sectional shape. It is the example made into the inclined plane which does not have.

On the other hand, the inclined portion outer surface 12b in the portion between the intermediate diameter portion 15 and the outer diameter portion 14 of the inclined portion 12 may be a curved surface as shown in FIGS.
Specifically, it may be a non-inclined plane as shown in FIG. 10 (a), or may be an inclined plane continuous from the inclined portion inner side surface 12a connected as shown in FIG. 10 (b).
Moreover, as shown in FIG.10 (c), the inclined curved surface inclined in the reverse direction to the inclined part inner surface 12a, or an inclined plane as shown with a wavy line may be sufficient.

In addition, the inclined portion inner surface 12a may be an inclined plane having no curvature in the cross-sectional shape as shown in FIGS. (FIGS. 11A to 11C are also schematic views, showing a case where the intermediate diameter portion 15 has a central axis O2 that is eccentric to the left in the figure with respect to the central axis O of the outer diameter portion 14. FIG. ing.)
Further, the inclined portion outer surface 12b may be a non-inclined plane as shown in FIG. 11A, or may be an inclined plane inclined in the same direction as the inclined portion inner surface 12a as shown in FIG. As shown in (c), an inclined plane inclined in the opposite direction to the inclined portion inner surface 12a may be used.

Of course, the shape of the inclined portion 12 may be a combination of those shown in FIGS. 10 and 11, and is not limited thereto.
As shown in FIGS. 10 and 11, the diaphragm 10 has a central axis O <b> 5 in which the cross-sectional shape in the SS section orthogonal to the central axis O is eccentric with respect to the central axis O. It becomes a rotationally symmetric shape around the center axis O5.

  Further, in the inclined portion 12, in the direction of the central axis O, from the position d1 of the reference plane P0 including the outer diameter portion 14 (position where the reference plane P0 intersects with the central axis O) to the position d2 of the inner diameter portion 13 (in the central axis O). The cross section is not limited to having a rotationally symmetric shape about the eccentric central axis O5 at all positions up to the position where the surface P13 including the inner diameter portion 13 intersects), and has a rotationally symmetric shape about the eccentric central axis O5. It is good also as a diaphragm of the shape where the position d exists partially as an eccentric surface part.

Further, except for the example as shown in FIG. 10 (b), the intermediate diameter portion 15 is a portion where the inclination angle or curvature of the surface of the inclined portion 12 changes suddenly, in other words, two portions connected with the portion as a boundary. It is set as a part where the curvature or inclination angle of the surface becomes discontinuous.
Moreover, this intermediate diameter part 15 is a site | part visually recognized as a boundary line from which the reflection condition of the light projected from one direction differs visually.
The intermediate diameter portion 15 is not limited to a perfect circle, and may be a rotationally symmetric figure having a central axis O2 eccentric with respect to the central axis O and around the eccentric central axis O2.
Further, the inner diameter portion 13 is not limited to a perfect circle, and may be a rotationally symmetric figure such as an ellipse.

In the above-described example, the diaphragm having the surface in which the central portion 11 is recessed has been described. However, the central portion 11 may be a flat surface or may have a protruding surface.
Further, the size of the central portion 11, in other words, the radial size of the inner diameter portion 13 may be set arbitrarily.
Therefore, for example, when the inner diameter portion 13 is a perfect circle, the size of the diameter D1 is arbitrary.

  The example of the outer shape of the diaphragm 10 described above has been described, but the outer shape may be a polygon (for example, a regular pentagon) inscribed in the circle. In that case, what is necessary is just to set a mutual dimension so that a polygonal external shape and an intermediate diameter part may not interfere.

Further, as shown in FIG. 11, the inclined portion outer surface 12b may be a curved surface having a center of curvature O4 on the opposite side to the protruding side of the central portion 11.
As an example, FIG. 11 shows a cross-sectional shape of a diaphragm 10R in which the inclined portion outer surface 12b is formed as a curved surface along a spherical surface CF having a radius R1.
The diaphragm 10R has the same shape as the diaphragm 10 of FIG. 4 except for the inclined portion outer surface 12b.

The diaphragm 10 described in detail above has a central axis in which the outer diameter portion 14 and the inner diameter portion 13 are coaxial even if there is an intermediate diameter portion 15 having a central axis O2 eccentric with respect to the central axis O of the outer diameter portion 14. Since it has O, the electroacoustic transducer (speaker unit) 50 can be comprised using the drive part 32 which has the edge 30, the housing 31, or the magnetic circuit 34 for general purpose.
In addition, the outer diameter portion 14 and the inner diameter portion 13 are formed so as to have a coaxial central axis O, and the center is eccentric by a predetermined distance α from the central axis O of the outer diameter portion 14 and the inner diameter portion 13. In the case where the intermediate diameter portion 15 having the axis O2 is provided, the generation of a symmetric standing wave with respect to the central axis is suppressed, and the peak and dip in the frequency-sound pressure characteristics are smoothed and flattened. it can.
In addition, in the inclined portion 12, the cross-sectional shape in any SS cross-section orthogonal to the central axis O has the central axis O5 that is eccentric with respect to the central axis O, and rotation about the eccentric central axis O5. Similarly, in the case of a symmetrical shape, the generation of a symmetric standing wave with respect to the central axis is similarly suppressed, and the peak and dip in the frequency-sound pressure characteristic can be smoothed and flattened.

<Second embodiment of diaphragm>
Next, a second embodiment 100 of the diaphragm that is a component of the spherical shell diaphragm of the embodiment will be described with reference to FIG.
FIG. 13 shows the basic shape of the diaphragm 100a as FIG. 13 (a), and FIG. 13 (b) shows the diaphragm 100 of the second embodiment in order to make it easy to grasp the shape of the diaphragm 100. It is the shown schematic plan view. Further, in FIGS. 13A and 13B, black circles are added to the points where the line segments intersect for easy understanding.

  The diaphragm 100 shown in FIG. 13B is positioned on the outer axis 14 while the diameter D1 that can be arbitrarily set in the inner diameter portion 13 of the first embodiment is set to substantially zero, and the outer diameter portion 14 is set. The top portion TP0 is located at a position projecting to one side with respect to the reference plane P0 set by including, while the top portion TP0 and the outer shape are rotationally symmetric about an axis eccentric with respect to the central axis O. This is a diaphragm in which a simple virtual figure is set and a plurality of top portions projecting on the same side as the top portion TP0 are provided on the virtual figure.

The diaphragm 100 has a shape in which almost no plane that is substantially orthogonal to the sound radiation direction (the direction of the central axis O) is eliminated.
The outer shape of the diaphragm 100 may be a regular n-gon (n: an integer equal to or greater than 4). Here, an example of a regular pentagon with n = 5 as shown in FIG. 13B will be described.

First, the basic shape diaphragm 100a shown in FIG.
The diaphragm 100a is a regular pentagon whose outer shape has vertices T1 to T5. Each vertex is located on the circumscribed circle C1.
It is surrounded by line segments T1G to T5G connecting the regular pentagonal center G0 (hereinafter also referred to as main center G0) and the vertices T1 to T5, and sides T1T2 to T5T1 which are line segments connecting adjacent vertices. Five triangles TR1 to TR5 and centroids G1 to G5 of these triangles TR1 to TR5 are set. (In the example of the diaphragm 100a, the centroids G1 to G5 coincide with the centers of the triangles TR1 to TR5).

Here, the vibration plate 100a has a top portion TP0 at a position where the positions of the main center G0 and the gravity centers G1 to G5 protrude toward one surface with respect to the reference plane P0 determined by including the vertices T1 to T5, respectively. And it is set as the shape which has the uneven surface folded in each line segment so that it may become top part TP1-TP5.
Specifically, the line segments T1G to T5G connecting the vertices T1 to T5 and the main center G0 are valley folds that form valley lines, and ten lines connecting the vertices T1 to T5 and the centroids G1 to G5. Let the minutes be mountain folds that form ridge lines (mountain lines). Further, the five top portions TP1 to TP5 are located on a circle C2 centered on the main center G0.

In contrast to the diaphragm 100a having such an uneven surface, the diaphragm 100 according to the second embodiment has the positions of the top portions TP1 to TP5 adjacent to the top portions TP1 to TP1 as shown in FIG. The line connecting TP5 is on the circle C2, and the center O3 of the circle C2 is decentered by a predetermined amount α from the regular pentagonal main center O (in this example, coincides with the center of gravity G0). The shape has been moved to.
FIG. 13B shows an example in which the eccentric direction is the direction approaching the vertex T1 (arrow direction).

Further, the diaphragm 100 is formed such that the main center G0 (top portion TP0) and the top portions TP1 to TP5 protrude to one surface side with respect to the reference plane P0. Each protrusion amount with respect to the reference plane P0 may be arbitrary.
Therefore, the main center G0 (top TP0) may protrude most with respect to the reference plane P0, or may protrude less (lower) than any of the tops TP1 to TP5. Of course, the protruding amounts may be the same.

Here, when the main center G0 is lower than the tops TP1 to TP5, the ridge lines from the tops TP1 to TP5 to the main center G0 are down, but the ridge lines from the vertices T1 to T5 to the main center G0 are ascending. Therefore, the main center G0 is referred to as the top portion TP0 for convenience.
Similarly, when the main center G0 is higher than the tops TP1 to TP5, the ridgelines from the main center G0 to the tops TP1 to TP5 are down, but the ridgelines from the vertices T1 to T5 to the tops TP1 to TP5. Since it is climbing, it is called the tops TP1 to TP5 for convenience.

  When the protrusion amounts of the top portions TP1 to TP5 with respect to the reference plane P0 are different, the diaphragm 100 may not include all the top portions TP1 to TP5 in the same plane. Alternatively, the apexes TP1 to TP5 may be all included in the same plane, and the plane may be non-parallel to the reference plane P0.

The diaphragm 100 is not limited to having the regular pentagon as described above, but may have a regular n-gon.
That is, this diaphragm has an outer shape of a regular n-gon (n: an integer of 4 or more), and the regular n-gon is divided into n by a line segment connecting the center (center of gravity) G0 and each vertex T1 to Tn. The center O3 of the figure drawn by the line C2 connecting these points TP1 to TPn at the positions of arbitrary points TP1 to TPn in each range in the n triangles TR1 to TRn obtained in this way is a regular n-gon. The center G0 and the points TP1 to TPn are set to be eccentric from the center G0 by a distance α, and are positioned as apexes protruding to one surface with respect to the reference plane P0 set by including the vertices T1 to Tn. A diaphragm having a shape.

Here, the line C2 connecting the points TP1 to TPn does not have to be a circle and may be a rotationally symmetric figure.
In addition, the main center G0 and the top portions TP1 to TPn only need to protrude to one surface side with respect to the reference plane P0 including the vertices T1 to Tn, and each protrusion amount with respect to the reference plane P0 is arbitrary.

Therefore, the main center G0 may protrude most with respect to the reference plane P0, and may protrude less (lower) than any one of the top portions TP1 to TPn. Of course, the protruding amounts may be the same.
In the diaphragm 100, when the protrusion amounts of the top portions TP1 to TPn with respect to the reference plane P0 are different, the top portions TP1 to TPn may not be included in the same plane. In this case, the top portions TP1 to TPn may be included in the same plane, and the plane may be non-parallel to the reference plane P0.

  Using the diaphragm 100 described above and the edge 30 having an inner periphery corresponding to the outer shape of the diaphragm 100 and having a circular outer shape, the inner periphery of the edge 30 is connected to the outer periphery of the diaphragm 100. If the outer periphery of the edge 30 is fixed to a general-purpose frame having a circular frame, the diaphragm 100 is supported by the frame through the edge 30 so as to vibrate freely. The (speaker unit) can be easily manufactured by using a general-purpose frame or a drive unit having a magnetic circuit while suppressing an increase in cost.

Moreover, in this diaphragm 100, it is preferable to join the voice coil bobbin 21 to a position corresponding to at least each of the top portions TP1 to TPn because vibration of the voice coil bobbin 21 can be transmitted to the diaphragm 100 more efficiently.
Further, if the voice coil bobbin 21 is fixed to the surface opposite to the side from which the top portions TP1 to TPn of the diaphragm 100 protrude, wider directivity can be obtained.
An example in which the diaphragm 100 and the voice coil bobbin 21 are connected in this manner is schematically shown in FIG. In FIG. 14, the sound is emitted so as to have a wide directivity as shown by the arrows in the figure.
FIG. 14 corresponds to the BB cross section of the diaphragm 100 shown in FIG. 13B. The intersection of the line segment T1G and the circle C2 as a rotationally symmetric figure in the diaphragm 100 is BC1, and the side T3T4. BC2 is the middle point.

The voice coil bobbin 21 is formed to have a cylindrical portion 21a and a joint portion 21b that is connected to one end side thereof and expands to the opening side. A voice coil 22 is wound around the outer peripheral surface on the other end side of the cylindrical portion 21a.
The tip of the joint 21b is bonded and fixed at a position corresponding to a circle C2 (see FIG. 13B) that connects the tops TP1 to TP5 of the diaphragm 100.
The voice coil bobbin 21 is fixed so that its tube axis Ob coincides with an axis passing through the top TP0 of the diaphragm 100 and orthogonal to the reference plane P0 (that is, the central axis O of the outer shape of the diaphragm 100). The
The tube axis Ob of the voice coil bobbin 21 coincides with the central axis of the drive unit 32.

  In the electroacoustic transducer using the diaphragm 100, the distribution of the standing wave becomes asymmetric with respect to the axis in an arbitrary cross section including the central axis, and as described above with reference to FIG. The effect of flattening the dip or peak in the pressure characteristic is obtained.

Further, in the electroacoustic transducer using the diaphragm 100, the diaphragm 100 does not have a plane orthogonal to the central axis O, and all the planes are inclined. Even in the high sound range where the listening area close to the axis O tends to be sharp with high sound pressure, the decrease in sound pressure caused by the angle with respect to the central axis O (sound pressure difference with respect to the front) becomes small and omnidirectional Properties close to the characteristics can be obtained.
When the directivity is close to omnidirectional, the listening position is not limited to a narrow range, and is useful in use environments such as halls, large rooms, streets, etc., and close to this electroacoustic transducer. When listening at a position, even if the listening position is deviated, the sound localization is not greatly shifted and it is possible to listen with natural movement of the position, which is very preferable.

Furthermore, as a result of diligent investigations by the inventors, in the diaphragm 100, in the diaphragm 100 in which the sound pressure difference depending on the listening position is small and a characteristic close to omnidirectionality is obtained, the main center G0 projects most with respect to the reference plane P0. The protruding main center G0, the tops TP1 to TPn, and the vertices T1 to Tn of the outer shape are found to be included in a spherical surface having a constant curvature.
This is because the overall shape of the diaphragm 100 is close to a part of a spherical surface although there are fine irregularities on the surface shape.
Therefore, the radial axis, which is the sound emission direction, is more uniformly distributed throughout the diaphragm 100 in the direction orthogonal to the spherical surface.

  Therefore, the electroacoustic transducer using the diaphragm 100 of this shape not only flattens the dip and peak in the frequency-sound pressure characteristics, but also the sound pressure difference due to the difference in angle with respect to the vibration direction of the diaphragm. The characteristic becomes closer to omnidirectionality.

Here, when n of the regular n-gon indicating the outer shape of the diaphragm 100 described above is infinite, the outer shape of the diaphragm 100 is a circle, and the plurality of top portions TP1 to TPn are infinite number of top portions. .
The top of the infinite number is a line that continuously circulates around the central axis O, and a circumferential line (diaphragm) in which the curvatures or inclination angles of two surfaces connected with this line as a boundary are discontinuous. 10 equivalent to the intermediate diameter portion 15).
In other words, the diaphragm 10 of the first embodiment can be regarded as the infinite diaphragm n of the diaphragm 100 of the second embodiment, and the diaphragms 10 and 100 of the first and second embodiments. Are easily understood from the two forms that can be applied from the technical idea of the present invention.

<About the electroacoustic transducer 150>
Next, the outer shape of the diaphragm 10 of the first embodiment described above is a regular pentagon, and a plurality of these are deployed and joined as shown in FIG. 15 to form a substantially regular dodecahedron as shown in FIG. The diaphragm 200 and the electroacoustic transducer 150 using the diaphragm 200 will be described in detail.
Further, in this example, the diaphragm 201 having a substantially regular dodecahedron shape and the electroacoustic transducer are deformed by using the diaphragm 100 of the second embodiment instead of the diaphragm 10 of the first embodiment. This will be described in detail as an example.
Further, the diaphragms 200 and 201 are combined with the plate-shaped diaphragms 10 and 100 as described above. In the following description, this form corresponds to the surface corresponding to the surface of a hollow sphere. For the sake of convenience, the shape including a regular dodecahedron is referred to as a spherical shell diaphragm (spherical shell diaphragm).

  The appearance of the electroacoustic transducer 150 is shown in FIG. The electroacoustic transducer 150 may be referred to as a spherical speaker or the like due to its form, or a breathing bulb speaker or the like due to the vibration mode of the diaphragm 200.

  The electroacoustic transducer 150 includes a substantially spherical shell-shaped diaphragm 200 (to be distinguished from a single diaphragm as described above, hereinafter, also referred to as a spherical shell diaphragm 200), and the spherical shell diaphragm 200. And a drive unit 232 (not shown) having a magnetic circuit 234 (not shown) that drives the spherical shell diaphragm 200 in the radial direction, and an outer side of the spherical shell diaphragm 200 that supports the drive unit 232. And a supporting leg 103 extending in the direction.

Although details will be described later, the magnetic circuit 234 includes a cup-shaped yoke 223, a magnet 224 fixed to the inner surface of the bottom 223 a of the yoke 223, and a pole piece 225 fixed to the magnet 224.
The drive unit 232 includes the magnetic circuit 234, a voice coil bobbin 221, and a voice coil 222.

Here, the spherical shell diaphragm 200 will be described with reference to FIG. 15. As described above, the spherical shell diaphragm 200 is prepared with eleven diaphragms 10 whose outer shape is a regular pentagon, and each diaphragm 10 sides are butted together and joined by a flexible edge 102 to form 11 of the regular dodecahedron.
In other words, the surface of a sphere having a predetermined diameter is approximately divided into 12 regular pentagons, and the diaphragm 10 is applied to each of 11 divided 12 regular pentagons. is there.
Therefore, the diaphragm 200 does not have one of the regular dodecahedrons, and this is an opening.
Hereinafter, the individual diaphragms 10 are also referred to as segments 101.

Returning to FIG. 16, one of the 12 surfaces (the surface indicated by the arrow in FIG. 16) that is the opening is a plate (not shown) in which holes for inserting the support legs 103 are formed instead of the diaphragm 10. )).
This plate is joined to the spherical shell diaphragm 200 via a flexible edge 102.
The support leg 103 inserted through the hole is also fixed in the hole.
An installation pedestal (not shown) is attached to one end portion 103a of the support leg 103, and the electroacoustic transducer 150 itself can be installed on the floor surface or suspended from the ceiling.

  The electroacoustic transducer 150 includes a total of eleven drive units 232 corresponding to each diaphragm 10, as is apparent from FIG. 17 showing a state where the spherical shell diaphragm 200 is removed.

Next, the configuration of the drive unit 232 and the like corresponding to one segment 101 that is each diaphragm 10 will be described with reference to FIG.
FIG. 18 shows a state in which the housing 31 is removed and the end of the diaphragm 10 which is the segment 101 and the end of the adjacent diaphragm 10 are connected via the edge 102 with respect to FIG. . A part of the adjacent diaphragm 10 is described.

One end portion of a circular voice coil bobbin 221 is connected and fixed to the diaphragm 10 on the surface opposite to the surface from which the inner diameter portion 13 protrudes.
In this state, the central axis O of the outer shape of the moving plate 10 and the tube axis Ob of the voice coil bobbin 221 coincide with each other.
A voice coil 222 is wound around the outer peripheral surface of the voice coil bobbin 221 on the other end side.
A cup-shaped yoke 223 is disposed outside the voice coil 222 so that the inner peripheral surface of the annular wall portion 223a faces the outer peripheral surface of the voice coil 222 with a gap.
In addition, a cylindrical pole piece 225 coupled to the magnet 224 is disposed inside the voice coil bobbin 221 so as to have a gap with the inner peripheral surface thereof.
A ring-shaped frame 235 is fixed to the yoke 223.
The voice coil bobbin 221 and the frame 235 are connected by two elastic dampers 233, and the voice coil bobbin 221 is elastically supported by the damper 233 so that it can move in a direction parallel to the central axis O with respect to the frame 235. Has been.
The magnet 224 is fixed to the bottom portion 223 a of the yoke 223, and the yoke 223 is fixed to the mounting surface portion 132 a of the support base 132. As the drive unit 232, one used for driving a diaphragm having an outer shape with the tube axis Ob of the voice coil bobbin 221 as the central axis can be used as it is.

As shown in FIG. 19, a total of eleven support bases 132 are attached to each of eleven of the twelve surfaces of the base body 130 assembled into a substantially regular dodecahedron by the base frame 131. .
Although not shown, the above-described support leg 103 is fixed to the remaining one surface of the base body 130.
As shown in FIG. 18, the mounting surface portion 132 a of the support base 132 has a tube shaft in which the bottom surface of the yoke 223 is the central axis O12 of each surface of the regular dodecahedron and the central axis of the driving portion 232 as described above. It is fixed so that Ob matches.

Therefore, the electroacoustic transducer 150 is fixed to the base body 130 so that the outer surface of the base body 130 has a substantially regular dodecahedron shape and the mounting surface portion 132a is positioned corresponding to the eleven of the regular dodecahedron surfaces. 11 support bases 132 and 11 drive parts 232 fixed to the attachment surface parts 132a of these support bases 132, respectively, and the voice coil bobbin 221 of each drive part 232 has a regular pentagonal outer shape. The diaphragm 10 is connected to each diaphragm 10 of a spherical shell diaphragm 200 which is assembled into a spherical shell by assembling 11 of the regular dodecahedron corresponding to 11 faces of a regular dodecahedron.
Therefore, the electroacoustic transducer 150 is supported by the spherical shell diaphragm 200 so that the center axis O of each diaphragm 10 coincides with the voice axis bobbin 221 of each of the plurality of drive units 232 and the tube axis Ob. Driven to vibrate in the normal direction of the sphere circumscribing the regular dodecahedron, emits sound.

As a result, the sound can be emitted almost in all directions with very little difference in sound pressure caused by the difference in emission angle.
Accordingly, when the electroacoustic transducer 150 is disposed in a hall or the like, for example, sound is emitted, a sound field with excellent presence is formed regardless of the listening position.
In addition, when listening to the sound emitted at a position close to the electroacoustic transducer 150, even if the listening position moves, the sound localization moves naturally without extremely moving, so that a good sense of realism is obtained. can get.

When the above-described diaphragm 10 is used as an individual diaphragm, the shape of the diaphragm 10 is such that the outer diameter portion 14 and the inner diameter portion 13 have a coaxial central axis O and a central axis O2 that is eccentric from the central axis O. When the intermediate diameter portion 15 is provided, generation of a symmetric standing wave with respect to the central axis O is suppressed, and a peak or dip in the frequency-sound pressure characteristics can be flattened.
Further, the shape of the diaphragm 10 is such that the outer diameter portion 14 and the inner diameter portion 13 have a coaxial central axis O, and the inclined portion 12 has a cross-sectional shape orthogonal to the central axis O around the central axis O2 that is eccentric from the central axis O. If the eccentric surface portion has a rotationally symmetric shape, the generation of a symmetric standing wave with respect to the central axis O is suppressed, and the peak and dip in the frequency-sound pressure characteristics can be flattened.

  Further, if a diaphragm 10R which is a modification of the diaphragm 10 as shown in FIG. 12 is used as each diaphragm, the inclined portion outer surface 12b has a curved surface along a part of the spherical surface CF. Therefore, the spherical shell diaphragm 200 has an external shape closer to that of a sphere, and the appearance quality as a spherical speaker is improved.

  Next, as a modification of this embodiment, a diaphragm 100 (see FIG. 13B and FIG. 20A) is used instead of the diaphragm 10, and the eleven diaphragms 100 are connected via the edge 102. The external appearance of the spherical shell diaphragm 201 formed into a substantially spherical shell by joining the sides so as to meet each other is shown in FIG. In this figure, the support leg 103 is omitted.

As shown in FIGS. 20A and 20B, the outer shape of each diaphragm 100 is a regular pentagon having vertices T1 to T5.
In FIG. 20A, the figure C2 connecting the tops TP1 to TP5 is a circle, and its center O3 is shifted by a distance α in the direction toward the vertex T1 with respect to the regular pentagonal main center G0. Yes.
Further, as can be seen from FIG. 20B, the main center G0 and the tops TP1 to TP5 protrude outward with respect to the reference plane P0 set including the vertices T1 to T5, and the amount of protrusion is the main center. It is formed so that G0 is the largest.
The voice coil bobbin 221 to be joined to the diaphragm 100 is the voice coil bobbin 221 described with reference to FIG. 14, and includes a surface corresponding to at least each of the top portions TP <b> 1 to TP <b> 5 of the diaphragm 100. It is fixed to the adhesive.

  When the spherical shell diaphragm 201 of this modification is used, each diaphragm 100 has a top GO TP0 that protrudes in one direction with respect to a reference plane P0 including the vertices T1 to T5 as the center GO of the outer shape. The center O3 of the figure C2 obtained by providing a plurality of protruding top portions TP1 to TP5 and connecting the top portions TP1 to TP5 between the center G0 and the outer shape (outer diameter portion 14) from the center G0 of the outer diameter portion 14. On the other hand, since the diaphragm surface is formed so that all the surfaces are inclined with respect to the direction orthogonal to the reference plane P0 which is the sound emission direction, the dip and peak in the frequency-sound pressure characteristics are flattened. In addition, the sound pressure difference due to the difference in angle formed with respect to an axis (center axis of the diaphragm 100) passing through the center G0 and orthogonal to the reference plane P0 is reduced, and characteristics close to omnidirectionality can be obtained.

  Further, as described in detail in the description of the diaphragm 100, the shape of the diaphragm 100 is such that the center G0 protrudes most with respect to the reference plane P0, the protruding center G0, the plurality of apexes TP1 to TP5, and each vertex of the outer shape. Forming T1 to T5 so as to be included in a spherical surface having a constant curvature is preferable when the sound pressure difference due to the difference in angle with respect to the central axis O of the diaphragm 100 is reduced and omnidirectionality is desired.

  In addition, if the constant curvature is matched with the curvature of the surface of the spherical shell diaphragm 201, the entire shape of the spherical shell diaphragm 201 becomes closer to a true sphere. Since the sound pressure difference due to the difference between the angles is smaller and the directivity is smoother, the directivity as the spherical shell diaphragm 201 is more preferable because the effect of being closer to omnidirectionality is obtained.

  When the spherical shell diaphragms 200 and 201 are respectively formed using the diaphragms 10 and 10R or the diaphragm 100 described above, the electroacoustic transducer 150 is set by setting the eccentric direction of each diaphragm 10 and 100 to a predetermined direction. Is preferably installed on the floor, for example, since the sound pressure fluctuation when the listening position with respect to it changes particularly in the latitudinal direction (vertical direction) is reduced. This eccentric direction will be described with reference to FIG.

In FIG. 21, the electroacoustic transducer 150 is installed so that the diaphragm on the top surface facing the plate on the bottom surface 10 </ b> B to which the support legs 103 are attached is a diaphragm 10 </ b> T and is parallel to the floor surface FL. It is a front view which shows a state. This is an example of installation. The diaphragm in FIG. 21 is a spherical shell diaphragm 200 using the diaphragm 10 of the first embodiment.
In this state, the sides where the five diaphragms 10-1 to 10-5 connected to the diaphragm 10T on the top surface and the five diaphragms 10-6 to 10-10 connected to the plate on the bottom surface 10B are joined are as follows. 21 is a joint portion at the boundary that divides the spherical shell diaphragm 200 into two at the top and bottom of FIG. 21, and becomes a zigzag line EQ. This line EQ is indicated by a thick broken line in FIG.

Considering this spherical shell diaphragm 200 as the earth, hereinafter, this line EQ will be referred to as the equator EQ, the top side from the equator EQ as the northern hemisphere, and the bottom side as the southern hemisphere.
The preferable eccentric direction of the diaphragms 10 and 100 is the direction toward the apex on the equator EQ in the diaphragms 10-1 to 10-5 in the northern hemisphere and the diaphragms 10-6 to 10-10 in the southern hemisphere. Setting the eccentric direction in this way is preferable because the fluctuation in sound pressure when the listening position changes in the latitude direction (vertical direction in FIG. 21) is reduced.

Furthermore, it is more preferable that the eccentric direction of the diaphragms 10-1 to 10-5 in the northern hemisphere and the eccentric direction of the diaphragms 106 to 10-10 in the southern hemisphere are reversed in the circumferential direction as shown in FIG.
Specifically, as shown by the arrows in FIG. 21, when viewed from the top, the diaphragms 10-1 to 10-5 in the northern hemisphere are eccentric in the clockwise direction toward the apex on the equator EQ, and the southern hemisphere. The diaphragms 10-6 to 10-10 may be eccentric in the counterclockwise direction toward the apex on the line EQ. The clockwise and counterclockwise directions may be reversed.
In this way, when the diaphragms on both sides connected by the line EQ that is a joint that bisects the spherical shell diaphragm 200 are eccentric in different circumferential directions, the listening position changes in the latitudinal direction. Sound pressure fluctuations are averaged, and the fluctuations are further reduced.

The line EQ is not limited to being set parallel to the floor surface FL. Depending on the listening position, the direction of the line EQ can be set as appropriate so as to obtain an optimum directivity characteristic at the listening position.
Further, since the support leg 103 may be extended in an arbitrary direction, the extension direction of the support leg 103 does not constrain the setting direction of the line EQ.

  On the other hand, when a listening position is assumed, it is preferable that the eccentric direction of the top diaphragm 10T is set as a direction approaching the listening position. In this way, the sound pressure fluctuation when the listening position moves up and down at that position is reduced.

By the way, when the edge 102 is formed of a particularly soft material, or when the spherical shell diaphragms 200 and 201 are relatively large, the shape of the spherical shell diaphragms 200 and 201 itself is not distorted by the weight. As shown by a two-dot chain line in FIG. 18, the edge 102 and the base body 130 may be connected by a support 236.
The support body 236 supports the spherical shell diaphragms 200 and 201 in addition to the voice coil bobbin 221 and provides elasticity so that the shape of the diaphragm does not deform and does not affect the vibration. It is formed with the material which has.

<Manufacturing process>
Next, a process of manufacturing the electroacoustic transducer 150 of the embodiment will be described mainly using FIG.
In this example, an example having a substantially regular dodecahedron spherical shell diaphragm 200 formed by combining a plurality of diaphragms 10 will be described. However, the diaphragms 10 </ b> R and 100 can be similarly manufactured instead of the diaphragm 10. can do.

(Step 1) First, the diaphragm 10 corresponding to each segment 101 is created by subjecting a plate-like or sheet-like diaphragm material to pressing or drawing. As the diaphragm material, paper, metal, resin, ceramics, or a wooden sheet can be used as described above. Each sheet may be a laminate of one or more kinds of sheets.

(Step 2) Next, 11 segments 101 are developed and arranged on a plane as shown in FIG. 15, the sides of the individual segments 101 that can be joined in this state are abutted, and the flexible segments 102 are respectively interposed. And join. For example, a rubber material or a resin material can be used for the edge, and a known adhesive can be used for bonding.

In this example, the process is performed up to the point where two segments 101 are joined to each side of the segment 101-C as the center.
Specifically, in FIG. 15, five segments 101-1 to 101-5 adjacent to one central segment 101-C are joined, and each of the segments 101-1 to 101-5 is segmented 101-. 6 to 101-10 are joined.
In this bonding form, two sides (indicated by a striped pattern in FIG. 15) that are separated from the segment 101-C are lines EQ.

Further, when expanding on a plane, the eccentric direction of the intermediate diameter portion 15 of each segment 101 is directed to the apex on the combined line EQ as described above (in the direction of the arrow in FIG. 15). Deploy.
When the arrangement of FIG. 15 is made to correspond to FIG. 21, for example, the segment 101-C becomes the top diaphragm 10T, the segments 101-1 to 101-5 are the northern hemisphere diaphragms 10-1 to 10-5, The segments 101-6 to 101-10 become the diaphragms 10-6 to 10-10 on the southern hemisphere side.

(Step 3) On the other hand, as shown in FIG. 19, the support base 132 is fixed to each of the 11 surfaces of the base body 130 formed in advance in a substantially regular dodecahedron shape by combining the base frame 131.
Then, the bottom surface 223a of the yoke 223 is fixed to the mounting surface portion 132a of the support base 132 with an adhesive or the like. A drive unit 232 is formed by attaching a magnet 224 or the like to which a pole piece 225 is fixed in advance to the yoke 223.

(Step 4) The movable part such as the voice coil bobbin 221 around which the voice coil 222 is wound is aligned with the fixed part such as the yoke 223 and the magnet 224 so that both are in a predetermined facing position as shown in FIG. It is attached via a damper 233. Bonding in this attachment can also be performed using an adhesive.
FIG. 17 shows the assembly 202 after the assembly.

(Step 5) Next, the 11 segments 101 partially joined in (Step 2) are put on the assembly 202 to which the 11 drive units 232 are attached.
At that time, each segment 101 is placed so as to correspond to each voice coil bobbin 221 attached in (Step 4).
Then, the end portion of the voice coil bobbin 221 is fixed to the inner surface of each segment 101 with an adhesive so that the central axis O of each segment 101 coincides with the tube axis Ob of the voice coil bobbin 221.

(Step 6) In this state, the sides that are not joined in step (2) in each segment 101 are positioned so as to be almost abutted with each other, so that these are bonded via the flexible edge portion 102. Are used to form a spherical shell diaphragm 200 having a substantially spherical shell shape.

(Step 7) The support leg 103 is fixed to the base body 130, a plate that closes the opening of the spherical shell diaphragm 200 is disposed in the opening, and the spherical shell diaphragm 200 and the support leg 103 are joined. The attachment of the support leg 103 and the base body 130 is not limited to the last, and may be performed in advance between other arbitrary processes.
The electroacoustic transducer 150 is manufactured by the above process.

  According to this manufacturing process, in (Step 2), each side of the segment 101 that can be joined in a state where the individual segments 101 are developed on a plane is joined in advance, and in the subsequent (Process 5) Since the respective sides are joined to each other, the positioning of the opposing portions when the segment 101 is assembled into a spherical shell is simplified, and the spherical shell diaphragm 200 can be easily assembled.

  In addition, each segment 101 has a polygonal central axis O which is an outer shape thereof and a driving central axis (tube axis of the voice coil bobbin 221) Ob of the driving unit 232, so A general-purpose drive unit 232 having a rotationally symmetric shape can be used. Further, the positioning of the movable part side and the fixed part side in the assembly work can be performed easily and accurately.

The electroacoustic transducer 150 applied to the present invention is not limited to the configuration described above, and may be modified without departing from the gist of the present invention.
For example, when the spherical shell diaphragm 201 is formed using the diaphragm 100 whose outer shape is a regular n-square shape, when n is 4 or 5, the lengths and directions of the sides are adapted to be normal with almost no gap. Can be connected to a polyhedron.
In addition, when n is 6 or more, a regular polyhedron cannot be formed. Therefore, when they are formed in a spherical shell shape, a gap is formed between them, but these gaps are closed with a flexible connecting member to connect each other. It can be set as a substantially spherical shell-shaped spherical shell diaphragm.

As described above, each segment 101 of the spherical shell diaphragm 200 is driven in the normal direction (direction orthogonal to the vibration surface) of each segment 101 by the drive unit 232.
The diaphragm 10 as each segment 101 is made of an elastic material and is connected to all eleven faces of a regular dodecahedron through a flexible edge 102.
Therefore, the heel is also driven like a breathing sphere.
As a result, the directivity characteristic of the sound radiated from the electroacoustic transducer 150 having the spherical shell diaphragm 200 is a wide directivity close to omnidirectional by drawing a smooth circle even in the high sound range as shown in FIG. Has characteristics.
That is, a characteristic close to a pattern radiated from a point sound source in all directions can be obtained. In other words, the electroacoustic transducer 150 having the spherical shell diaphragm 200 can be regarded as a point sound source. .

Therefore, as shown in FIG. 23, in the reflective directional speaker 500 of this embodiment, the sound S1 from the electroacoustic transducer 150 does not depend on the radiation direction with respect to the inner surface 520a of the reflector 520, and Irradiates uniformly regardless of frequency.
Further, according to FIG. 23, the sound pressure reaching the listener J1 on the central axis CL, which is the vibration axis 0 ° of the electroacoustic transducer 150, reaches the listeners J2 and J3 away from the vibration axis. The sound pressure of the sound to be played is almost equal, and the high sound range arrives with almost the same sound quality as the original sound without attenuation.

  For this reason, the sound S2 reflected by the inner surface 520a reaches the listening area with a constant sound pressure and sound quality, and even if the listener moves within the area, the volume and quality of the sound to be heard may change. Demonstrate no directivity, sound pressure and sound quality characteristics.

Further, in any listening area, the best condition, that is, the highest volume, that is, high quality listening that allows the high sound range to be heard satisfactorily is possible.
Therefore, there is no problem that the listener has to search for the best listening position while moving in the area.

  As described above, the inner surface 520a of the reflecting plate 520 is a paraboloidal surface or a surface of a spheroid. Therefore, when the electroacoustic transducer 150 is disposed at the focal position, the inner surface 520a is best described above. Each characteristic can be obtained.

<Second embodiment>
Next, a reflective directional speaker 500A in which the reflection plate 520 of the first embodiment described above is provided with a rotation drive mechanism 521 and a control unit 535 for controlling the rotation drive mechanism 521 will be described as a second embodiment.
In the reflective directional speaker 500A of the second embodiment, the rotation driving mechanism 521 is operated according to an instruction from the control unit 535, and the reflection plate 520 and the electroacoustic transducer 150 are moved in an arbitrary direction. It is driven to rotate so that it faces.
Thereby, the listening area corresponding to the opening direction can be set in an arbitrary direction.

  In FIG. 24, the reflective directional speaker 500A is supported by the reflective directional speaker 500 of the first embodiment, a chassis base 550 that supports the reflective directional speaker 500, and a support portion (not shown) on the chassis base 550. A rotation drive mechanism 521 and a control unit 535 are provided.

The rotational drive mechanism 521 includes a fan-shaped gear 531 provided on the opposite side of the opening 520c of the reflector 520, a motor 534 as a drive source, a first gear 532 attached to the shaft of the motor 534, and the first gear 532. The first gear 532 and the fan-shaped gear 531 mesh with each other, and a second gear 533 that transmits the rotational force of the motor 534 to the reflecting plate 520 is configured. The motor 534 is driven by a drive signal from the control unit 535.
Further, the reflection plate 520 is supported by a support shaft (not shown) provided on the rotation axis RC passing through the center CTR of the electroacoustic transducer 150 so as to be rotatable around the rotation axis RC.
The rotation axis RC is most preferably located at the center CTR of the electroacoustic transducer 150 because there is no movement of the sound source accompanying rotation when the electroacoustic transducer 150 is regarded as a point sound source.
As the distance from the center CTR is increased, the range required for the rotation operation becomes wider. Therefore, when the installation range is limited or when it is preferable that the movement of the point sound source associated with the rotation is less, the position closer to the center CTR. It is desirable to set the rotation axis RC.

  With the above configuration, when the motor 534 is driven in a predetermined direction by an instruction from the control unit 535, the driving force is transmitted to the fan-shaped gear 531 via the first gear 532 and the second gear 533, and the reflector 520 is , About the rotation axis RC in the direction of the arrow Rd in FIG.

FIG. 25 shows a state where the reflector 520 is rotated downward relative to the position shown in FIG. 24 by this rotation.
By adopting such a configuration, for example, the control unit 535 controls the sound emission direction, which is the direction of the opening 520c of the reflection plate 520, to be directed toward the listener. Even in the direction, it is possible to provide an optimal sound field for the listener. The control unit 535 is configured to perform control based on listener direction information indicating the listener direction input by a known method.

For example, an infrared sensor can be provided to know the human body temperature, and the direction in which the body temperature exists can be used as listener direction information.
In addition, a data input unit may be provided, and listener direction information may be input from the input unit using, for example, numerical values of coordinates and directions.

<Example 3>
Next, an example in which a signal processing unit 551 that individually processes and controls signals input to each of the plurality of driving units 232 included in the electroacoustic transducer 150 will be described as a third embodiment.

FIG. 26 shows the third embodiment, and shows a reflective directional speaker 500B in which a signal processing unit 551 is further provided in the reflective directional speaker 500 of the first embodiment.
By applying a predetermined process to the signal applied to each drive unit 232 of the electroacoustic transducer 150, it is possible to further enhance the sense of localization and presence of the emitted sound.
Specifically, a signal generation unit 551e that generates a pulse signal SG3 that is a reference signal for individually outputting to each drive unit 232 that drives each segment 101, and the generated pulse signal SG3 to each drive unit A signal output unit 551g that outputs to the H.232, a microphone 552 that is a sound detection unit that detects the output sound at the listening point LP and outputs it as a pseudo noise signal SG1, and a pseudo noise signal SG1 output from the microphone 552. Based on the correlation calculation unit 551a that calculates the impulse response SG2 from each segment 101 to the listening point LP, and the average delay time calculation unit that calculates the average delay time Tmv of the impulse response SG2 calculated by the correlation calculation unit 551a 551b and the average of the impulse response SG2 calculated by the average delay time calculation unit 551b Based on the delay time Tmv, includes a delay processing unit 551C outputs to the driving unit 232 respectively delay the input sound signal SGIN from an external audio device 553 as an output sound signal SGOUT, the.

  In addition, the average delay time Tmv calculated by the average delay time calculation unit 551b is stored in the storage unit 551d, and when the condition regarding sound reproduction does not change, the pseudo noise signal SG1 from the microphone 552 is used. Instead, the stored value can be read from the storage unit 551d and used at any time.

  The operations of the correlation calculation unit 551a, the average delay time calculation unit 551b, the storage unit 551d, the signal generation unit 551e, and the delay processing unit 551c described above are controlled by the control unit 551f.

  In FIG. 26, signal lines connecting the respective drive units 232 and the signal processing unit 551 are schematically shown. In practice, the signal lines are connected through the inside of the support legs 103 or the signal processing unit 551 itself. Is housed in a base body 130 disposed inside the electroacoustic transducer 150.

  With the configuration described in detail above, the output signal SGOUT output to each drive unit 232 corresponding to each segment 101 can be independently generated even if the change in phase and sound pressure caused by the reflection of the reflector 520 is slight. Therefore, the quality of the reproduced sound of the reflective directional speaker 500B can be further improved.

  It goes without saying that the signal processing unit 551 described above may be configured to optimally process not only the output signal delay processing but also the volume and frequency characteristics.

  In addition, the signal processing unit 551 described above may be applied to a single electroacoustic transducer 150 that does not include the reflection plate 520. In this case, for example, if control is performed so that the output of the segment 101 facing the listener is increased, a certain degree of directivity can be exhibited even if the reflector 520 is not provided.

<Fourth embodiment>
Next, the reflection type directional speaker 500 of the first embodiment is provided with an electro-acoustic transducer 150 and an axial drive mechanism 570 that varies the relative position in the axial direction of the support leg 103 and the reflection plate 520. A type directional speaker 500C will be described as a fourth embodiment with reference to FIG.
According to the third embodiment, the strength of the directivity obtained in the first embodiment can be varied.

  As shown in FIG. 27A, the axial direction drive mechanism 570 provided in the reflective directional speaker 500C includes a motor 571, a first gear 572 attached to the shaft of the motor 571, and the support leg 103. , A pinion gear (second gear) 573 that meshes with the rack 574 and the first gear 572, and a controller 575 that controls the driving of the motor 571. The entire reflective directional speaker 500C is supported by a frame (not shown).

  In this configuration, when the motor 571 is driven in a predetermined direction according to an instruction from the control unit 575, the driving force is transmitted to the support leg 103 through the first gear 572, the pinion gear 573, and the rack 574 as the linear motion in the axial direction. Is done.

  Therefore, the position of the electroacoustic transducer 150 on the axis CL with respect to the reflecting plate 520 can be set to an arbitrary position with respect to the reflecting plate 520, which will be described with reference to FIG. 27, the axial drive mechanism 570 shown in FIG. 27A is omitted in FIGS. 27B and 27C.

As shown in FIG. 27A, when the position of the center CTR of the electroacoustic transducer 150 on the axis CL with respect to the reflection plate 520 is at the position of the focal point ST of the shape of the inner surface 520a of the reflection plate 520, The sound reflected by the inner surface 520a is radiated as a sound parallel to the axis CL.
In addition, as shown in FIG. 27B, when this position is in front of the position of the focal point ST in the shape of the inner surface 520a of the reflector 520 (on the opening 520c side), the sound reflected by the inner surface 520a is Radiated in the direction of convergence on CL, and becomes narrow directivity.
As shown in FIG. 27C, when this position is behind the position of the focal point ST in the shape of the inner surface 520a of the reflector 520 (on the opposite side of the opening 520c), the sound reflected by the inner surface 520a is Radiated in the direction of divergence with respect to the axis CL, and becomes wide directivity.

  In this way, the directivity can be changed to a desired characteristic according to the situation of the listener.

Needless to say, the fourth embodiment described above may be combined with other embodiments.
In particular, when combined with the first embodiment, not only can the direction of sound emission be selected, but also the directivity sharpness can be controlled arbitrarily.

As described above, according to each of the embodiments described in detail, since the electroacoustic transducer 150 has a wide directional characteristic that is close to omnidirectionality, the sound of the sound that is reflected by the reflector and reaches the limited listening area The pressure is constant, the sound quality is constant, and even if the listener moves within the region, the movement of the sound localization does not become extreme, and an extremely high-quality listening sound and listening environment can be provided.
In particular, each diaphragm 10 constituting the spherical shell diaphragm 150 used in the electroacoustic transducer 150 is arranged around a central axis in which any cross section perpendicular to the axis of the drive unit of the inclined portion is eccentric from the central axis of the outer shape. Since it is formed so as to have two or more rotationally symmetric shapes, the generation of standing waves is suppressed, and a good reproduced sound with less dip and peaks in the sound pressure-frequency characteristics of the radiated sound is provided to the listening area. Can do.

  The electroacoustic transducer 500 according to the embodiment is not limited to the configuration described above, and may be modified without departing from the gist of the present invention.

It is a perspective view which shows the reflection type electroacoustic transducer of the Example of this invention. It is sectional drawing explaining the reflection type electroacoustic transducer of the Example of this invention. It is a schematic perspective view which shows the element of the diaphragm applied to this invention. It is the top view and sectional drawing which show the element of the diaphragm applied to this invention. It is sectional drawing which shows the electroacoustic transducer using the element of the diaphragm applied to this invention. It is sectional drawing which shows the other example of the electroacoustic transducer using the element of the vibration evening applied to this invention. It is a schematic diagram for demonstrating standing wave distribution in the conventional diaphragm. It is a schematic diagram for demonstrating standing wave distribution in the element of the diaphragm applied to this invention. It is a graph which shows the frequency-sound pressure characteristic according to the amount of eccentricity of a diaphragm. It is typical sectional drawing for demonstrating the shape of the element of the diaphragm applied to this invention. It is typical sectional drawing for demonstrating the other shape of the element of the diaphragm applied to this invention. It is the top view and sectional drawing which show the other shape of the element of the diaphragm applied to this invention. It is a front view for comparing and explaining the shape of a conventional diaphragm and other shapes of diaphragm elements applied to the present invention. It is typical sectional drawing for demonstrating the electroacoustic transducer using the thing of the other shape of the element of the diaphragm applied to this invention. It is an expanded view for demonstrating the diaphragm used in the Example of this invention. It is an external view which shows the electroacoustic transducer used in the Example of this invention. It is a perspective view for demonstrating the structure of the electroacoustic transducer used in the Example of this invention. It is a fragmentary sectional view for demonstrating the electroacoustic transducer used in the Example of this invention. FIG. 19 is another perspective view for explaining the structure of the electroacoustic transducer used in the embodiment of the present invention. It is the front view and perspective view for demonstrating the modification of the diaphragm used in the Example of this invention. It is a front view for demonstrating the electroacoustic transducer of the Example of this invention. It is a figure which shows the directional characteristic of the spherical-shell-shaped electroacoustic transducer in the electroacoustic transducer used in the Example of this invention. It is sectional drawing explaining an effect | action of the reflection type electroacoustic transducer of the Example of this invention. It is a schematic diagram explaining the reflection type electroacoustic transducer of 2nd Example of this invention. It is another schematic diagram explaining the reflection type electroacoustic transducer of 2nd Example of this invention. It is a block diagram explaining the reflection type electroacoustic transducer of 3rd Example of this invention. It is typical sectional drawing explaining the reflection type electroacoustic transducer of 4th Example of this invention. It is a figure which shows the directivity of the conventional electroacoustic transducer. It is a figure explaining the characteristic of the conventional directional speaker.

Explanation of symbols

10, 10R, 100 Diaphragm 11 Central portion 12 Inclined portion 12a Inclined portion inner side surface 12b Inclined portion outer side surface 13 Inner diameter portion 14 Outer diameter portion 15 Intermediate diameter portions 21, 221 Voice coil bobbin 21a Cylindrical portion 21b Joint portion 22, 222 Voice coil 22a Lead wire 23, 223 Yoke 23a Bottom 23b Annular wall 24, 224 Magnet 25, 225 Pole piece 30 Edge 31 Housing 31a Hole 32, 232 Drive 33 Damper 34, 234 Magnetic circuit 50, 150 Electroacoustic transducer 200, 201 Sphere Shell diaphragms 10a, 100a (as a reference example) Diaphragm 101 Segment 102 Edge 103 Support leg 130 Base 131 Base frame 132 Support base 132a Mounting surface 202 Assembly 235 Frame 236 Support 500, 500A to 500C Electroacoustic Exchanger (reflective directional speaker)
520 Reflector 520a Inner surface 520b Hole 520c Opening 521 Rotation drive mechanism 531 Fan-shaped gear 532 First gear 533 Second gear 534 Motor 535 Control unit 550 Chassis base 551 Signal processing unit 551a Correlation calculation unit 551b Average delay time calculation unit 551c Delay processing Unit 551d storage unit 551e signal generation unit 551f control unit 551g signal output unit 552 microphone 553 audio device 570 axial drive mechanism 571 motor 572 first gear 573 (second gear) pinion gear 574 rack 575 control unit D1-D3 diameter FL floor surface G0 Main center (center)
G1 to Gn Center of Gravity LP Listen Point α (Eccentric) Distance O3 Center O4 Center of Curvature O, O2, O5, O12 Center Axis Ob (Voice Coil Bobbin) Pipe Axis P0 Reference Plane P13 Plane SG1 Pseudo Noise Signal SG2 Impulse response SG2a Alternative impulse response SG3 Pulse signal SGIN Input sound signal SGOUT Output sound signal ST Focus Tmv Average delay time T1 to Tn Apex TP1 to TPn Apex R, R1 Curvature α Distance (Eccentricity)

Claims (6)

A polyhedral diaphragm formed by connecting a plurality of diaphragms having a polygonal outer shape with a flexible coupling member, an electroacoustic transducer having a drive unit for vibrating the polyhedral diaphragm, and a bowl-shaped reflection A board,
The electroacoustic transducer according to claim 1, wherein the electroacoustic transducer is arranged at a position facing the inner surface of the reflector.   An inner surface of the reflecting plate is formed of a part of a rotating paraboloid or a part of a surface of a spheroid, and the electroacoustic transducer is disposed on an axis of symmetry of the inner surface. The reflective electroacoustic transducer according to claim 1.   The reflection type electroacoustic transducer according to claim 1 or 2, further comprising a rotating means for rotating the electroacoustic transducer and the reflecting plate around a predetermined axis.   The reflection type electroacoustic transducer according to any one of claims 1 to 3, further comprising an axial direction moving unit that moves the electroacoustic transducer in a contact / separation direction with respect to the reflection plate. .   A plurality of driving units that vibrate each diaphragm are provided in each of the plurality of diaphragms, and a signal output unit that outputs a signal independently to each of the plurality of driving units is provided. 5. The reflection type electroacoustic transducer according to 1 to 4. Comprising sound detection means for detecting sound from the electroacoustic transducer;
The signal output means includes
A signal generation unit that generates a predetermined reference signal and outputs the generated reference signal to the electroacoustic transducer;
Based on the sound of the reference signal output from the electroacoustic transducer and detected by the sound detection means, the sound signal to be reproduced by the electroacoustic transducer is independently delayed with respect to each of the plurality of driving units. The reflection type electroacoustic transducer according to claim 5, further comprising: a delay processing unit that outputs the signal.

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