JP5304230B2 - Flat speaker - Google Patents

Description

  The present invention relates to a flat panel speaker installed and used on a wall or ceiling of a living space such as a house or office building.

  As shown in FIG. 7, a conventional ceiling-mounted speaker of this type has a soundproof cover that covers the back of the frame in order to reduce the sound on the back of the frame.

  That is, as shown in FIG. 7, the conventional ceiling-mounted speaker 1 is installed by being vertically inserted through the ceiling panel 2, and the grill 3 is attached to the surface of the ceiling panel 2. Most of the speakers including the drive unit are installed on the back side of the ceiling panel 2, and the soundproof cover 4 is designed to cover the frame 8.

  The drive unit includes a magnetic circuit 5 and a voice coil bobbin 7 around which a voice coil 6 is wound.

  The ceiling-mounted speaker 1 includes a diaphragm 9, a damper 10, an edge 11 and a dust cap 12 in addition to the drive unit and the frame 8. The ceiling-mounted speaker 1 is connected to the ceiling panel 2 by joining the end of the opening 13 provided in the ceiling panel 2 and the outer periphery of the frame 8.

  The magnetic circuit 5 includes a lower plate 14, a magnet 15, and an upper plate 16.

  In such a conventional ceiling-mounted speaker, a conical soundproof cover 4 formed of a material such as a hard resin is provided so as to cover the frame 8, whereby sound leaks to the back of the ceiling-mounted speaker 1. Was preventing.

In addition, the following patent document 1 is known as a prior art document regarding this application.
JP 2007-96546 A

  Since the conventional ceiling-mounted speaker 1 is provided with the soundproof cover 4 so as to cover the outside of the frame 8, the thickness of the flat speaker 1 is increased by the amount of the soundproof cover 4. For this reason, it has a problem that it is difficult to install in a general house where the space between the ceiling and the upper floor is narrow.

  Therefore, an object of the present invention is to make it possible to easily install a speaker provided with a soundproofing device even in a general house where the space between the ceiling and the upper floor is narrow.

  In order to achieve this object, the present invention provides a dish-shaped frame provided with an opening, a diaphragm provided in the opening of the frame, and provided in the frame, coupled to the diaphragm, A flat speaker provided with a driving unit for vibrating a diaphragm, wherein one or more first acoustic tubes are installed in the frame, thereby achieving an initial purpose.

  In the flat speaker according to the present invention, since the first acoustic tube that reduces the sound of the band that becomes annoying is installed in the frame, the leakage sound to the back surface can be suppressed without increasing the overall thickness. It can be installed easily even in ordinary houses where the space between the floor and the upper floor is narrow.

(Embodiment 1)
Hereinafter, the flat speaker of Embodiment 1 will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view taken along line AA in FIG. 2, which is a plan view of flat speaker 17 in the first embodiment. FIG. 2 is a plan view of the flat speaker 17. FIG. 3 is a perspective view of a frame in the embodiment. FIG. 4 is a perspective view of the first acoustic tube 18 in the same embodiment.

  As shown in FIGS. 1 and 2, the flat speaker 17 according to the present embodiment includes an iron dish-shaped frame 19 provided with an opening, and a flat diaphragm 20 provided in the opening of the frame 19. And a drive unit that is installed in the dish-shaped frame 19 and is coupled to each of the frame 19 and the diaphragm 20 to vibrate the diaphragm 20. Further, one or more first acoustic tubes 18 are installed on the bottom surface of the dish-shaped frame 19.

  The diaphragm 20 made of a thin tree that also serves as a ceiling board has a substantially flat plate shape. Therefore, the opening of the frame 19 is also rectangular, and the rectangular diaphragm 20 is installed in a rectangular opening of the frame 19 and is in a sealed state. The diaphragm 20 can also be formed of other ceiling plates, for example, a lightweight hard material resin plate, a foamed resin plate, a metal plate, or the like. In that case, different sound quality can be enjoyed for each material of the diaphragm. In Embodiment 1, the shape of diaphragm 20 is a square shape, but may be other shapes such as a circle or a polygon. In that case, there is an effect that the degree of freedom in designing the speaker increases.

  The drive unit includes a magnetic circuit 21 placed at the center between the inner bottom surface of the frame 19 and the diaphragm 20 and a voice coil bobbin 23 around which the voice coil 22 is wound.

  The magnetic circuit 21 is configured such that a yoke 24 is fixed to the center of the bottom of the frame 19 and a magnet 25 and an upper plate 26 are provided thereon, and a magnetic gap is provided between the yoke 24 and the upper plate 26. .

  The voice coil 22 is inserted in the magnetic gap of the magnetic circuit 21, and the voice coil bobbin 23 around which the voice coil 22 is wound is connected to the diaphragm 20 via a coupler 27 that transmits vibration to the diaphragm 20. ing.

  The damper 28 has an inner peripheral side connected to the voice coil bobbin 23, and an outer peripheral side of the damper 28 is connected to the back surface of the annular recess 19 a in the frame 19 to support the voice coil bobbin 23.

  As shown in FIG. 3, the first acoustic tube 18 is disposed between the annular recess 19 a in the frame 19 and the outer frame portion of the frame 19, and is installed on the bottom surface of the frame 19.

  As shown in FIG. 4, the first acoustic tube 18 made of lightweight iron has an opening 18a at one end and an end 18b opposite to the opening 18a, and the end 18b is closed. It has a structure. The material of the first acoustic tube can be formed of a metal other than resin, wood, or iron. In that case, when resin and wood are used, there is an effect that the weight can be reduced. Moreover, when light metals, such as aluminum, are used, there exists an effect that it can be made lightweight, maintaining a certain amount of rigidity.

  Further, the first acoustic tube 18 may be integrally formed with the frame 19 in addition to being integrated with the frame 19 and installed on the frame 19 by bonding means such as adhesion. In that case, the number of parts and man-hours can be reduced.

  When sound is reproduced from the flat speaker 17, sound waves radiated to the back side of the diaphragm 20 enter the opening 18a of the first acoustic tube 18 in FIG. 4 installed in the frame 19, and enter the terminal end 18b. Is reflected and emitted from the opening 18a again. At that time, the sound wave having the frequency corresponding to the quarter wavelength has a half-wavelength in the reciprocating path, and the phase of the reflected wave in the opening 18a is opposite to the sound that has entered, so Disappear or greatly reduce. Sound waves close to the tube length of the acoustic tube close to ¼ wavelength do not disappear in the opening 18a, but the sound pressure becomes a value close to 0. Therefore, the sound reflected at the opening 18a becomes soft. Therefore, it is possible to effectively reduce the sound in a certain frequency range centered on the frequency of the ¼ wavelength sound by one first acoustic tube 18.

  Based on the above-mentioned principle, the first acoustic tube 18 that matches the frequency band of the leaking sound that becomes annoying is installed inside the frame 19, thereby leaking to the back side (upper floor side) of the flat speaker 17. It can reduce the sound of annoying bands that can be produced, and can be installed on a ceiling with a narrow space to enjoy music without disturbing people on the upper floor.

  Note that in the ceiling-mounted flat panel speaker 17, leakage sound of 150 Hz or more and 250 Hz or less is often particularly disturbing by measurement of sound waves radiated to the back side of the diaphragm 20, and is adjusted to the wavelength of these sounds. A great effect can be obtained by using the first acoustic tube 18 having a length of 34 cm to 56 cm. In addition, the first acoustic tube 18 having a length corresponding to the wavelength of the leaking sound can be installed depending on the case, not limited to the above frequency.

  Further, in the embodiment of the present invention, the shape of the first acoustic tube 18 is L-shaped, but the same effect can be obtained even if it is straight, S-shaped, curved, or other shapes. . When the shape of the first acoustic tube 18 is a straight line, the moldability becomes good, so that the quality can be stabilized and the cost can be reduced. Moreover, by making the shape of the first acoustic tube 18 into an S shape or a curved shape, an acoustic tube having a desired length can be disposed even in a space-saving space.

  Furthermore, although the cross-sectional shape of the tube of the first acoustic tube 18 is rectangular, the same effect can be obtained even when the shape is circular or elliptical. When the cross-sectional shape is circular, the moldability becomes good, so that the quality can be stabilized and the cost can be reduced. In addition, when the cross-sectional shape is an ellipse, a thinner acoustic tube can be realized as compared with a rectangular or circular cross-section, so that the effect of being excellent in installation is achieved. However, in order to prevent a standing wave from being generated in the width direction of the first acoustic tube 18, the equivalent diameter D (tube width) of the cross section of the tube and the wavelength λ of the sound are D <0. It is necessary to satisfy the relationship of 59λ.

  In the present embodiment, the drive unit is coupled to the frame 19 and the central part of the diaphragm 20, but may be coupled with the center being shifted. In that case, it is possible to disperse the divided resonance generated on the diaphragm 20, and to obtain a frequency characteristic in which peak dip is suppressed.

  The drive unit may be configured using any one of an electrodynamic exciter, a magnetostrictive exciter, and an electrostrictive exciter.

(Embodiment 2)
Hereinafter, the flat speaker 29 according to Embodiment 2 of the present invention will be described with reference to FIGS. In order to prevent the explanation from becoming complicated, the same parts as those in the first embodiment are denoted by the same reference numerals, and the explanation is simplified.

  FIG. 5 is a perspective view of the flat speaker 29 according to Embodiment 2 of the present invention. In FIG. 5, the second acoustic tube 30 is installed outside the frame 19, that is, on the outer bottom surface side of the frame 19. That is, a concave portion 19a that protrudes into the frame 19 is provided on the bottom surface of the frame 19, and the second acoustic tube 30 is installed in the concave portion 19a. However, even in this state, as is apparent from FIG. 6, the second acoustic tube 30 is provided within the thickness of the frame 19. It is in the state where it is arranged. With this configuration, it is possible to reduce the sound radiated from the flat diaphragm 20 to the front and wrapping around the ceiling by the second acoustic tube 30, and further reduce the sound leaking to the upper floor. .

  Furthermore, in the second embodiment, the second acoustic tube 30 is installed outside the frame 19, but a resonance sound absorber having a duct and a hollow portion or a porous sound absorbing plate may be used instead. The effect of can be obtained.

  In the flat speaker according to the present invention, the thickness of the flat speaker is not increased by installing the acoustic tube for reducing the sound in a band that is annoying to the inside of the flat speaker. For this reason, when installing a flat speaker on a wall or ceiling, it reduces the sound leakage from the back to the surrounding space without increasing the thickness of the flat speaker, and has the effect of suppressing the sound radiated to the adjacent room / upper floor. It is useful as an acoustic device composed of building materials such as houses, apartments, and offices.

Sectional drawing in AA of the top view (FIG. 2) of the flat speaker in Embodiment 1 of this invention. FIG. 3 is a plan view of the flat speaker according to Embodiment 1 of the present invention. The perspective view of the frame of the flat speaker in Embodiment 1 of this invention The perspective view of the acoustic tube of the flat speaker in the same embodiment The perspective view of the flat speaker in Embodiment 2 of this invention Cross-sectional view of the structure of a flat speaker according to Embodiment 2 of the present invention Cross-sectional view of the structure of a conventional soundproof speaker

Explanation of symbols

17 flat speaker 18 first acoustic tube 18a opening 18b terminal 19 frame 19a recess 20 diaphragm 21 magnetic circuit 22 voice coil 23 voice coil bobbin 24 yoke 25 magnet 26 upper plate 27 coupler 28 damper 29 flat speaker 30 second acoustic Tube D Tube width

Claims (4)

A dish-shaped frame with an opening;
A diaphragm provided in the opening of the frame;
A flat speaker provided with a driving unit that is provided in the frame and coupled to the diaphragm and vibrates the diaphragm;
Wherein in the frame, the first acoustic pipe for reducing a portion of the reproduced sound radiated to the rear side of the diaphragm is installed one or more,
Wherein the outer surface of the frame, a recess entered toward the frame provided, the flat plate speaker which the second acoustic tube, characterized in Rukoto installed in this recess. The flat speaker according to claim 1 , wherein the second acoustic tube is a resonant sound absorber or a porous sound absorbing plate. The flat speaker according to claim 1 or 2 , wherein the first and second acoustic tubes have a structure in which one end is closed. The flat speaker according to any one of claims 1 to 3 , wherein the first and second acoustic tubes are made of one or more kinds of materials of resin, wood, or metal.

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