JPH08126083A - Speaker system - Google Patents

Abstract

PURPOSE: To secure excellent acoustic state by reducing surely an undesired sound heard unnaturally in which frequency is fluctuated in response to various conditions of installed environment of the speaker system. CONSTITUTION: The speaker system 32 is made up of a speaker box 34 in which a speaker 38 is provided to a front buffle plate 37 provided to an opening of a front side of a box 36 and of a placing base 35 with the speaker box 34 mounted thereon to be a prescribed height. A sound absorbing material 42 containing ENC fluid constituent including EA particles having EA effect into an electric insulating medium is adhered to the inner face of the placing base 35. A voltage is applied to the ENC fluid constituent forming the absorbing material 42 and the voltage is adjusted by a variable power supply 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speaker system used for stereos and the like.

[0002]

2. Description of the Related Art Conventionally, a speaker body is mounted on a pedestal so that its height can be adjusted to the position of a listener's ear. By the way, it is preferable that the pedestal on which the speaker body is placed has high rigidity in order to sufficiently output low-pitched sound from the speaker. However, if the rigidity is increased as described above, unnecessary sound is output. However, there was a problem that it would be enlarged. For this reason,
As disclosed in Japanese Patent No. 6077, a plurality of holes are formed in a pedestal, bottles of various sizes and shapes are inserted into these holes as needed, and these bottles are used as a resonator to unnaturally It has been considered to reduce unwanted sound.

[0003]

However, the above-mentioned pedestal has a problem that the appearance of the pedestal is impaired because the appearance thereof is remarkably poor. In addition, the frequency of unwanted sound that reverberates unnaturally changes depending on the installation location of the speaker and the installation environment (room temperature, humidity, number of people in the room, etc.). You have to insert it into the hole in the pedestal,
The adjustment work was very troublesome. Further, it is extremely difficult to find a bin for a frequency of an unnecessary sound that is desired to be reduced, and there is a problem that adjustment cannot be completed reliably.

By the way, the inventors of the present invention have developed a fluid composition for electro-sensitive sound wave absorption control (hereinafter referred to as "Electric Noise-Control") having a novel electric field arrangement characteristic (hereinafter referred to as "EA characteristic") which has not been known. The fluid composition is abbreviated as “ENC fluid composition”). The ENC fluid composition is, for example, a fluid obtained by dispersing solid particles in an electrically insulating medium. When an electric field is applied to the fluid, the solid particles cause dielectric polarization, and electrostatic attraction based on the dielectric polarization is generated. Have a property of exhibiting a chain structure by being coordinately linked to each other and aligned. In addition, some solid particles exhibit the property of exhibiting an array lump structure by electrophoresis and array alignment. As described above, the alignment orientation of particles under an electric field is determined by the electric field alignment effect (hereinafter, referred to as Electric Alignment).
The t effect is abbreviated as “EA effect”), and the solid particles having such properties are referred to as electric field arranging particles (hereinafter, electric field arranging particles are abbreviated as “EA particles”). . And the present inventors have found that the EN of this novel structure is
The present invention was reached by advancing research into C-fluid compositions.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a speaker system capable of extremely easily reducing only harmful sound in accordance with the installation environment.

[0006]

In order to achieve the above object, a speaker system according to a first aspect of the present invention comprises a speaker main body having a speaker provided on a front plate, and a mounting table on which the speaker main body is mounted. A speaker system, wherein the mounting table includes a sound absorbing material containing an ENC fluid composition in which EA particles having an EA effect are contained in an electrically insulating medium, and the ENC fluid forming the sound absorbing material. It is characterized in that it comprises a voltage applying means for applying a voltage to the composition and adjusting the applied voltage. A speaker system according to a second aspect is the speaker system according to the first aspect, wherein the sound absorbing material is provided on at least a front surface of the mounting table. According to a third aspect of the present invention, the speaker system according to the first or second aspect is characterized in that the sound absorbing material is provided on a front plate provided with the speaker.

[0007]

According to the speaker system of claim 1,
A voltage is applied from the voltage applying means to the ENC fluid composition constituting the sound absorbing material, and the applied voltage value is adjusted,
By adjusting to the frequency of the unnecessary sound that is output from the speaker body and reverberates unnaturally, the sound of that frequency is reduced. Furthermore, even if the frequency of the sound that reverberates unnaturally changes due to the room temperature, humidity, the number of people in the room, etc., it can be adjusted to the changing frequency by changing the applied voltage value.

That is, the sound absorbing material has an EA effect in the ENC fluid composition when no voltage is applied.
The A particles are randomly suspended and dispersed in the electrically insulating medium. When a voltage is applied to the pair of electrode plates by the voltage applying means, the EA particles are arranged and linked in a chain shape to form a chain (particle chain).
Are formed, and the chains are arranged parallel to the electric field direction.
When a sound wave (air vibration) is applied to one of the electrode plates in this state, the electrode plate vibrates in the opposite direction, but the chain body itself has elasticity, so the chain body is stretched. When the particles are opposed to each other, they attract each other to generate an attractive force, and when they are compressed, they bend to generate a repulsive force, which causes a viscous resistance due to the movement of the chain in the electrically insulating medium, which causes a sound wave. Loss of energy (dissipation) occurs.

That is, the sound wave incident on the electrode plate causes the ENC fluid composition containing the chain to resonate with the electrode plate.
The sound wave frequency that gives vibration to such a chain is determined by the characteristic frequency of the chain (which is presumed to be the so-called natural frequency, which is the balance between the elasticity of the chain and the inertia of the electrode plate). When a sound wave having a frequency matching the characteristic frequency is incident on the electrode plate, the chain resonates and absorbs the sound wave, and sound waves of other frequencies are reflected. Since the attractive force (stress generated in the chain) acting between each particle increases with the increase of the voltage applied to the pair of electrode plates,
The elastic modulus and viscosity of the chain itself increase as the applied voltage increases, and the present invention utilizes this fact. In other words, by adjusting the applied voltage so that the characteristic frequency of the chain itself matches the frequency of the component of the incident sound wave (air vibration) that you want to remove, the chain resonates and absorbs sound. It consumes the energy of the component to be (removed) and reflects the other components.

FIG. 10 is a graph showing the results of measuring the effect of the electric field strength on the EA characteristics for a 30 wt% EA particle dispersion system. It is clear from this graph that the stress acting on the chain increases as the applied voltage increases. EA
The characteristic is that the dielectrically polarized particles are arranged in the direction of the electric field by an electric attraction to form a chain structure. At low shear rates, electrical attraction dominates, resulting in a gradual cycle of breaking and reforming chain structures. The yield stress is the force that is generated when a chain arranged in the direction of the electric field undergoes shear failure in the direction perpendicular to it. Considering that the particles of all chains formed have the same diameter and connect the electrode plates in a straight line, the number of chains is proportional to the particle concentration.
The yield stress will also be proportional to the particle concentration. FIG. 11 shows an equivalent circuit of the vibration system, that is, a coil spring 22 having an elastic modulus K and a dashpot 23 having a viscosity C are connected in parallel between a pair of electrode plates.

According to the speaker system of the second aspect, since at least the sound absorbing material is provided on the front surface of the mounting table where the vibration due to the sound output from the speaker is most easily transmitted, the mounting table resonates. The generation of unnatural sound is surely prevented. According to the speaker system of the third aspect, the sound absorbing material reduces the vibration of the front plate to which the speaker is attached, prevents blurring of the sound image, and secures a good sense of localization.

[0012]

Embodiments of the speaker system of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 31 is an audio system. This audio system 31
Is a speaker system 32 of this embodiment arranged on both sides, and a CD player, a record player, a cassette deck, which outputs audio to, for example, compact discs, records, cassette tapes, radios, etc., to these speaker systems 32. The audio device main body 33 includes a tuner and an amplifier. As shown in FIG. 2, a speaker system 32 constituting the audio system 31 includes a speaker box (speaker body) 34 and a mounting table on which the speaker box 34 is mounted and positioned at the height of a listener's ear. 35
It is composed of and.

The speaker box 34 is attached to the box body 36 having an opening on the front side, a front baffle plate (front plate) 37 provided in an opening on the front side of the box body 36, and the front baffle plate 37. It is composed of a plurality of speakers 38. Table 35
As shown in FIGS. 2 and 3, the sound absorbing material 42 having the ENC fluid composition is attached to the inner peripheral surface including at least the front surface side of the base body 41 formed in a box shape. A variable power source (voltage source) that applies a voltage to the ENC fluid composition that constitutes the sound absorbing material 42 and adjusts the applied voltage inside the base body 41 by turning a knob 43 projecting from the surface side. Application means) 13 is provided. That is, according to the speaker system 32 having the above configuration, when a voltage is applied from the variable power source 13 to the ENC fluid composition of the sound absorbing material 42, the sound absorbing material 42 absorbs the sound of the frequency corresponding to the voltage value applied. It is supposed to do.

Next, the ENC fluid composition constituting the sound absorbing material 42 will be described. One example of an ENC fluid composition is shown in FIG. In this ENC fluid composition, EA particles 2 which are solid particles are uniformly dispersed in an electrically insulating medium 1. The EA particles 2 are composed of a core body 3 made of an organic polymer compound and a surface layer 5 made of particles 4 which are electric field aligning inorganic substances (hereinafter referred to as “EA inorganic substances”). Is forming. In this specific example, the electrically insulating medium 1 is colorless and transparent silicone oil, the organic polymer compound forming the core body 3 of the inorganic / organic composite particles is polyacrylic ester, and the EA inorganic substance forming the surface layer 5 is used. The particles 4 are white titanium hydroxide that is an inorganic ion exchanger and an electric semiconductor inorganic substance. The color of the EA particles (inorganic / organic composite particles) is, for example, white. The proportion of the EA particles 2 contained in the electrically insulating medium 1 is, for example, 7.5% by weight.

As shown in FIG. 7, this ENC fluid composition is interposed between a pair of electrode plates 7 and 8 which are spaced apart and arranged in parallel. As shown in FIG. 8, this pair of electrode plates 7,
When a voltage is applied to the power source 8 from the power source 9 through the switch 10, the EA particles 2 are arranged in a chain in a direction perpendicular to the surfaces of the electrode plates 7 and 8 due to the EA effect to form a chain body (particle chain) 6. Form. At this time, the chain-like bodies 6 are separated from each other and oriented in parallel.

Next, a sound wave absorption control device (sound control device) using the above ENC fluid composition will be described.
As shown in FIG. 4, a pair of electrode plates 17 and 18 are opposed to each other with a gap (composition containing space) therebetween, and the EA effect of the present invention described above is provided between the pair of electrode plates 17 and 18. An ENC fluid composition containing the EA particles 2 contained therein in an electrically insulating medium 1 is contained. One (lower)
The electrode plate 18 is fixedly arranged on a fixing member (not shown), and the other electrode plate 17 is flexible against sound waves, for example, P
It is evenly adhered to the lower surface of the ET (polyethylene terephthalate) film 17a. The pair of electrode plates 17,
A frame-shaped seal member 15 is fixed to the periphery of 18 and the periphery of the PET film 17a.

The ENC fluid composition of the present invention is housed in the space defined by the pair of electrode plates 17 and 18 and the seal member 15 in a sealed state. The one electrode plate 17 and the PET film 17a have their peripheral edges fixed, but are configured so that they can be vibrated in the facing direction of the pair of electrode plates 17 and 18 (the vertical direction indicated by the arrow X). Accordingly, when the sound wave (air vibration) 11 is incident on the PET film 17a, the PET film 17a
The electrode plate 17a and one electrode plate 17 can vibrate vertically.

The variable power source 13 comprises a pair of electrode plates 17, 18
A voltage is applied between them and the applied voltage is adjusted, and a switch 14 is connected in series to the variable power source 13. By turning on this switch 14,
A voltage can be applied between the pair of electrode plates 17 and 18. The sound wave absorption control device is usually in the form of a rectangular plate or a circular plate in appearance, but of course, it has an appropriate shape according to the place where it is installed.

Next, the operation of the sound wave absorption control device having the above configuration will be described. As shown in FIG. 4, a pair of electrode plates 1
When no voltage is applied between 7 and 18, ENC
The EA particles 2 of the fluid composition are randomly suspended and dispersed in the electrically insulating medium 1 (see FIG. 7). A pair of electrode plates 1
When a voltage is applied to 7, 18, E in the ENC fluid composition
The A particles 2 are arranged and linked in a chain to form a chain (particle chain) 6, and the chain 6 is arranged parallel to the electric field direction (see FIG. 8).

In this state, when a sound wave (air vibration) 11 is made incident on one of the electrode plates 17, (a), (b) of FIG.
The states of (c) and (d) occur sequentially, and the electrode plate 17 vibrates in the opposite direction as shown by the arrow X (see FIGS. 4 and 5) together with the PET film 17a. Due to its elastic nature, it is shown in FIG. 9 (b).
As shown in FIG. 9, when the chain body 6 is compressed, the chain body 6 bends, for example, in a V shape to generate a repulsive force, and as shown in FIG. When pulled, the EA particles 2 facing each other attract each other to generate an attractive force. As a result, due to the movement of the chain-like body 6 in the ENC fluid composition, viscous resistance is generated and energy loss (dissipation) of the sound wave 11 occurs.

As the electrode plate 17 vibrates,
The chain 6 is repeatedly pulled and compressed,
As a result, the chain body 6 itself also vibrates. That is, the sound wave 11 incident on the electrode plate 17, the ENC fluid composition containing the chain body 6, the electrode plate 17 and the PET film 17
The electrode plate structure composed of a resonates. The sound wave frequency that gives vibration to the chain 6 is as follows.
When the sound wave 11 having a frequency that is determined by the characteristic frequency of the beam enters the electrode plate 17, the chain 17 resonates (see arrows A and B in FIG. 5) and absorbs the sound wave. , Sound waves 12 of other frequencies will be reflected.

Since the force acting between the EA particles 2 (stress generated in the chain 6) increases with an increase in the voltage applied to the pair of electrode plates 17 and 18, the elasticity of the chain 6 itself. The modulus and viscosity increase with increasing applied voltage. The present invention utilizes this fact to remove a desired component of a sound wave. That is, by adjusting the applied voltage,
By matching the characteristic frequency of the particle chains 6 with the frequency of the component (sound wave having a specific wavelength) to be removed in the sound wave (air vibration) incident on the electrode plate 17, as shown in FIG. The body 6 is caused to resonate by the action of the inertial force as indicated by the left and right arrows A and B, and the energy of the component of the incident sound wave 11 to be removed is consumed, while the other sound wave components (reference numeral 1) are consumed.
2) is reflected. In this way, the applied voltage can absorb the component of the desired specific wavelength of the incident sound wave.

The characteristic frequency of the sound wave absorption control device changes depending on the size of the EA particles (solid particles), the elastic force acting between the EA particles, the natural frequency of the electrode plates and the distance between the electrode plates. In this example, since spherical EA particles having a substantially uniform particle size were dispersed in the electrically insulating medium (without using irregular particles), the above-mentioned repulsive force and attractive force were not generated under a constant voltage. It does not fluctuate, and furthermore, the balance between the elastic force acting between the EA particles and the inertial force of the electrode plate does not fluctuate easily.
In the above-mentioned embodiment, the chain body is supposed to be bent in a V shape, but in addition to this, for example, an S-shape as shown in FIG. 12 (a) or (b) in FIG. It is considered that there is a case where the wire is bent into a W shape as shown in ().

In the above embodiment, the phenomenon in which the EA particles (inorganic / organic composite particles) 2 form a row of chain-like bodies 6 and are arranged in parallel by the application of an electric field has been described. When the number of slabs exceeds several% by weight, 1
Instead of the chain bodies 6 in rows, the chain bodies 6 are joined to each other in a plurality of rows to form and arrange the columns 19 as shown in FIG. In this column 19, the left and right chain-shaped EA particles 2 are staggered by one and adjoin each other. With respect to this, the inventors of the present invention, as shown in FIG. 13B, have the EA particles 2 that are dielectrically polarized in the + pole portion and the − pole portion.
It is presumed that this is because it is more stable in terms of energy when the positive pole portion and the negative pole portion are alternately arranged adjacent to each other. Furthermore, although the ENC fluid composition is directly accommodated between the pair of electrode plates in the above-described embodiment, the present invention is not limited to this, and the porous body sufficiently impregnated with the ENC fluid composition is used as the pair of electrodes. It may be housed between the plates. In this case, the porous body preferably has open cells so as not to impair the EA effect.

Examples of the electrically insulating medium 1 used in the ENC fluid composition of the present invention include diphenyl chloride, butyl sebacate, aromatic polycarboxylic acid higher alcohol ester, halophenyl alkyl ether, trans oil, paraffin chloride, fluorine. Any fluid or mixture thereof, such as a system oil, a silicone oil or a fluorosilicone oil, as long as it has high electric insulation and electric breakdown strength, is chemically stable, and can stably disperse EA particles. Can also be used. This electrically insulating medium 1 can be colored according to the purpose. For coloring, it is preferable to use a type and amount of an oil-soluble dye or a dispersible dye that is soluble in the selected electrically insulating medium and does not impair its electrical properties. The electrically insulating medium 1 may further contain a dispersant, a surfactant, a viscosity modifier, an antioxidant, a stabilizer and the like.

The kinematic viscosity of this electrically insulating medium 1 is 1 cS.
It is preferably in the range of t to 30,000 cSt. When the kinematic viscosity is less than 1 cSt, the storage stability of the ENC fluid composition is insufficient, and the kinematic viscosity is 30,000 c.
If it is larger than St, it becomes difficult to uniformly disperse the EA particles, and it becomes difficult for the bubbles to be caught during the adjustment, and the bubbles will not come out easily, which is not preferable. From this viewpoint, the kinematic viscosity is preferably in the range of 10 cSt to 1000 cSt, particularly preferably in the range of 10 cSt to 100 cSt. Of course, the kinematic viscosity of the electrically insulating medium 1 changes with temperature, and this temperature effect can be suppressed by the applied voltage.

The EA particle 2 used in the present invention is an inorganic / organic composite particle having an EA effect, such as an element, an organic compound, an inorganic compound, or a mixture thereof.
Either material can be used. Examples thereof include particles of inorganic ion exchangers, metal oxides, silica gel, inorganic substances having electric semiconductors, carbon black, and particles having these as a surface layer. However, as shown in the above examples, the EA particles 2 are composed of the core body 3 made of an organic polymer compound and the EA inorganic particle 4
It is particularly preferable that the inorganic-organic composite particles are formed by the surface layer 5 consisting of. In this inorganic-organic composite particle, a surface layer 5 composed of particles 4 of EA inorganic material having a relatively high specific gravity is carried on a core body 3 which is an organic polymer compound having a relatively low specific gravity, and the specific gravity of the entire particle is changed to an electric value. It can be adjusted to approximate the insulating medium 1. Therefore, the ENC fluid composition obtained by dispersing this in the electrically insulating medium 1 has excellent storage stability.

Examples of the organic polymer compound that can be used as the core 3 of the EA particles (inorganic / organic composite particles) 2 include poly (meth) acrylic acid ester, (meth) acrylic acid ester-styrene copolymer, Polystyrene, polyethylene, polypropylene, nitrile rubber, butyl rubber, AB
S resin, nylon, polyvinyl butyrate, ionomer, ethylene-vinyl acetate copolymer, vinyl acetate resin,
One or a mixture of two or more such as a polycarbonate resin or a copolymer may be mentioned.

Particles 4 which are the EA inorganic substance forming the surface layer 5
Although various compounds can be used, preferred examples include inorganic ion exchangers, silica gel, and electrically semiconducting inorganic substances. When these particles 4 are used to form the surface layer 5 on the core 3 made of an organic polymer compound, the obtained inorganic / organic composite particles become useful EA particles 2.

Examples of the above inorganic ion exchanger include (1)
Hydroxide of polyvalent metal, (2) hydrotalcites,
(3) Acid salt of polyvalent metal, (4) Hydroxyapatite, (5) Nasicon type compound, (6) Clay mineral, (7)
Mention may be made of potassium titanates, (8) heteropolyacid salts, and (9) insoluble ferrocyanide.

The respective inorganic ion exchangers will be described in detail below. (1) Hydroxide of polyvalent metal. These compounds are represented by the general formula MOx (OH) y (M is a polyvalent metal, x is a number of 0 or more, and y is a positive number), and examples thereof include titanium hydroxide and zirconium hydroxide. ,
Examples include bismuth hydroxide, tin hydroxide, lead hydroxide, aluminum hydroxide, tantalum hydroxide, niobium hydroxide, molybdenum hydroxide, magnesium hydroxide, manganese hydroxide, and iron hydroxide. Here, for example, titanium hydroxide refers to hydrous titanium oxide (also known as metatitanic acid or β-titanic acid, Ti
It contains both O (OH) ₂ ) and titanium hydroxide (also known as orthotitanic acid or α-titanic acid, Ti (OH) ₄ ), and the same applies to other compounds.

(2) Hydrotalcites. These compounds have the general formula M ₁₃ Al ₆ (OH) ₄₃ (C
O) ₃ · 12H ₂ O (M is a divalent metal),
For example, the divalent metal M is Mg, Ca or Ni. (3) Acid salt of polyvalent metal. These are, for example, titanium phosphate, zirconium phosphate, tin phosphate, cerium phosphate, chromium phosphate, zirconium arsenate, titanium arsenate, tin arsenate, cerium arsenate, titanium antimonate, tin antimonate, tantalum antimonate. , Niobium antimonate, zirconium tungstate, titanium vanadate, zirconium molybdate, titanium selenate, and tin molybdate.

(4) Hydroxyapatite. These are, for example, calcium apatite, lead apatite,
Examples include strontium apatite and cadmium apatite. (5) Nasicon type compound. These include, for example, (H ₃ O) Zr ₂ (PO ₄ ) ₃ but in the present invention, a Nasicon type compound in which H ₃ O is replaced with Na can also be used. (6) Clay mineral. These are, for example, montmorillonite, sepiolite, bentonite and the like, with sepiolite being particularly preferred.

(7) Potassium titanates. These general formula _{aK 2 O · bTiO 2 · nH} 2 O (a 0
<A is a positive number that satisfies a ≦ 1, b is a positive number that satisfies 1 ≦ b ≦ 6, and n is a positive number), for example, K ₂ ·
TiO ₂ · 2H ₂ O, K ₂ O · 2TiO ₂ · 2H ₂ O, 0.
5K ₂ O ・ TiO ₂・ 2H ₂ O, and K ₂ O ・ 2.5TiO
₂ · 2H ₂ O, and the like. In addition, among the above compounds, a compound in which a or b is not an integer is easily synthesized by subjecting a compound in which a or b is an appropriate integer to an acid treatment and replacing K with H.

(8) Heteropolyacid salt. These are represented by the general formula H ₃ AE ₁₂ O ₄₀ .nH ₂ O (A is phosphorus, arsenic, germanium, or silicon, E is molybdenum, tungsten, or vanadium, and n is a positive number), For example, ammonium molybdophosphate and ammonium tungstophosphate. (9) Insoluble ferrocyanide. These are compounds represented by the following general formula. Mb-pxa
A [E (CN) ₆ ] (M is an alkali metal or hydrogen ion, A is a heavy metal ion such as zinc, copper, nickel, cobalt, manganese, cadmium, iron (III) or titanium, E is iron (II), iron (III), cobalt (II) or the like, b is 4 or 3, a is a valence of A, and p is a positive number of 0 to b / a.) These include, for example, Cs. Insoluble ferrocyanine compounds such as ₂ Zn [Fe (CN) ₆ ] and K ₂ Co [Fe (CN) ₆ ] are included.

The inorganic ion exchangers (1) to (6) each have an OH group, and some or all of the ions present at the ion exchange sites of these inorganic ion exchangers are different ions. Those substituted with (hereinafter, referred to as a substitutional inorganic ion exchanger) are also included in the inorganic ion exchanger of the present invention. That, R-M ¹ inorganic ion exchanger described above (M ¹ represents an ion species of the ion exchange sites) is expressed as a part or all of M ¹ in the R-M ^1, the ion exchange reaction below A substituted inorganic ion exchanger in which an ionic species M ² different from M ¹ is substituted by
It is an inorganic ion exchanger in the present invention. xR−M ¹ + yM ² → Rx− (M ² ) y + xM ¹ (where x and y represent the valences of the ion species M ² and M ¹ , respectively). M ¹ varies depending on the type of the inorganic ion exchanger having an OH group, but when the inorganic ion exchanger exhibits a cation exchange property, M ¹ is generally H ⁺ , and in this case, M ² is an alkali metal or an alkali. Any metal ion other than H ⁺ , such as earth metals, polyvalent typical metals, transition metals or rare earth metals. When the inorganic ion exchanger having an OH group exhibits anion exchange property, M ¹ is generally OH ^−.
Where M ² is, for example, I, Cl, SCN, N
Any of anions other than OH ⁻ such as O ₂ , Br, F, CH ₃ COO, SO ₄ or CrO ₄ and complex ions.

Further, regarding the inorganic ion exchanger which has once lost the OH group due to the high temperature heat treatment but becomes to have the OH group again by an operation such as immersion in water, the inorganic ion after the high temperature heat treatment is used. Exchangers and the like are also a kind of inorganic ion exchangers that can be used in the present invention, and specific examples thereof include a Nasicon type compound such as (H ₃ O) Zr ₂
(PO ₄₎ HZr ₂ obtained by heating ₃ (PO _{4) 3} and high-temperature heat treatment of hydrotalcite (500 to 70
Heat treated at 0 ° C.) and the like. These inorganic ion exchangers can be used not only in one kind but also in many kinds simultaneously as a surface layer. It is particularly preferable to use a hydroxide of a polyvalent metal and an acid salt of a polyvalent metal as the above-mentioned inorganic ion exchanger.

An example of an electrically semiconductive inorganic material that can be used as the surface layer 5 of the EA particles (inorganic / organic composite particles) 2 is a metal having an electric conductivity of 10 ³ to 10 ^-11 Ω ^-1 / cm at room temperature. Oxides, metal hydroxides, metal oxide hydroxides, inorganic ion exchangers, or metal-doped at least one of these, or at least any one of these regardless of the presence or absence of metal doping For example, those applied as an electric semiconductor layer on another support.

Examples of preferable electrically semiconductive inorganic substances are shown below. (A) Metal oxide: For example, SnO ₂ or amorphous titanium dioxide (manufactured by Idemitsu Petrochemical Co., Ltd.). (B) Metal hydroxide: For example, titanium hydroxide or niobium hydroxide. Here, titanium hydroxide means hydrous titanium oxide (manufactured by Ishihara Sangyo Co., Ltd.), metatitanic acid (also known as β-titanic acid,
TiO (OH) ₂ ) and orthotitanic acid (also known as α-titanic acid, Ti (OH) ₄ ) are included. (C) Metal oxide hydroxide: For example, FeO
(OH) (goethite) and the like can be mentioned. (D) Hydroxide of polyvalent metal: equivalent to inorganic ion exchanger (1). (E) Hydrotalcites: Inorganic ion exchanger (2)
Equivalent to (F) Acid salt of polyvalent metal: equivalent to the inorganic ion exchanger (3). (G) Hydroxyapatite: Inorganic ion exchanger (4)
Equivalent to (H) Nashicon type compound: equivalent to the inorganic ion exchanger (5). (I) Clay mineral: equivalent to the inorganic ion exchanger (6). (J) Potassium titanate: equivalent to the inorganic ion exchanger (7). (K) Heteropolyacid salt: equivalent to the inorganic ion exchanger (8). (L) Insoluble ferrocyanide: equivalent to inorganic ion exchanger (9). (M) Metal-Doped Electric Field Alignment Inorganic Material: This is an ER inorganic material doped with a metal such as antimony (Sb) in order to increase the electric conductivity of the above-mentioned electric semiconductor inorganic materials (A) to (L). As an example, antimony (Sb) -doped tin oxide (SnO ₂ ) and the like can be mentioned. (N) EA inorganic material applied as an electric semiconductor layer on another support: for example, titanium oxide, silica as a support,
Examples thereof include inorganic particles such as alumina and silica-alumina, or organic polymer particles such as polyethylene and polypropylene, to which antimony (Sb) -doped tin oxide (SnO ₂ ) is applied as an electric semiconductor layer. . The particles in which the EA inorganic substance is applied to the other support as described above can be regarded as the EA inorganic substance as a whole. These EA minerals are not only one type, but two
It is also possible to use types or more simultaneously as the surface layer.

The EA particles (inorganic / organic composite particles) 2 can be manufactured by various methods. For example, there is a method in which a particulate core body 3 made of an organic polymer compound and fine particulate particles 4 are transported by a jet stream and collided with each other to produce them. In this case, the fine particles of the particles 4 collide with the surface of the particulate core 3 at a high speed and are fixed to form the surface layer 5. Another example of the manufacturing method is a method in which the particulate core body 3 is suspended in a gas, and a solution of the particles 4 is atomized and sprayed on the surface. In this case, the surface layer 5 is formed by adhering the solution onto the surface of the core 3 and drying it.

A particularly preferred method for producing the EA particles (inorganic / organic composite particles) 2 is to form the surface layer 5 at the same time as the core body 3. In this method, for example, when emulsion-polymerizing, suspension-polymerizing, or dispersion-polymerizing a monomer of an organic polymer compound forming the core body 3 in a polymerization medium, particles 4 which are EA inorganic particles in the form of fine particles, Alternatively, it is present in the polymerization medium. Water is preferred as the polymerization medium, but a mixture of water and a water-soluble organic solvent can also be used, and an organic poor solvent can also be used. According to this method, the monomers are polymerized in the polymerization medium to form the core particles 3, and at the same time, the fine particle EA inorganic particles 4 are layered on the surface of the core 3 to cover the core particles 3. The surface layer 5 is formed.

In the case of producing EA particles (inorganic / organic composite particles) by emulsion polymerization or suspension polymerization, the EA inorganic particles 4 are combined by combining the hydrophobic property of the monomer and the hydrophilic property of the EA inorganic substance. Can be attached to the surface of the core body 3. According to the method of simultaneously forming the core body 3 and the surface layer 5, the EA inorganic particles 4 are densely and firmly adhered to the surface of the core body 3 made of an organic polymer compound, and the EA particles (inorganic / organic composite) Particles 2) are formed.

The shape of the EA particles 2 used in the present invention does not necessarily have to be spherical, but when the particulate core 3 is produced by the controlled emulsion / suspension polymerization method, the EA obtained is obtained. The shape of the particles 2 is almost spherical. EA
The particle size of the particles 2 is not particularly limited, but is 0.1
The thickness is preferably in the range of μm to 500 μm, particularly 5 μm to 200 μm. Fine particle EA at this time
The particle size of the inorganic particles 4 is not particularly limited, but is preferably 0.005 μm to 100 μm, and more preferably 0.01 μm to 10 μm.

In the EA particles (inorganic / organic composite particles) 2, the particles 4 and the core 3 which are the EA inorganic substance forming the surface layer 5 are formed.
The weight ratio of the organic polymer compound forming the is not particularly limited, but in order to obtain an ENC fluid composition having high storage stability, the EA inorganic particles 4 and the organic polymer compound core 3 are used. 1% by weight of particles 4 to 6% of the total weight
It is preferably in the range of 0% by weight, particularly preferably in the range of 4% by weight to 30% by weight. If the proportion of the core 3 is less than 1% by weight, the EA characteristics of the obtained EA particles 2 will be insufficient, and if it exceeds 60% by weight, the specific gravity of the EA2 particles will be excessive and the storage stability may be impaired. There is. Further, the ENC fluid composition of the present invention can be produced by uniformly stirring and mixing the above-mentioned EA particles 2 together with a dispersant and other components in an electrically insulating medium. As the stirrer, any stirrer normally used for dispersing solid particles in a liquid dispersion medium can be used. In an electrically insulating medium 1
The content of the EA particles 2 in is not particularly limited, but is preferably 0.5 to 75% by weight, and particularly preferably 5 to 50% by weight. If the content is less than 1%, a sufficient EA effect cannot be obtained, and if the content is 75% or more, the initial viscosity of the ENC fluid composition when a voltage is not applied becomes too large, which makes it difficult to use.

The EA particles 2 produced by the above-mentioned various methods, particularly the method of simultaneously forming the core 3 and the surface layer 5,
The whole or part of the surface layer 5 may be covered with a thin film of an organic polymer substance, a dispersant used in the manufacturing process, an emulsifier or other additive substances, and the EA effect as EA particles may not be sufficiently exhibited. . This thin film of inert material can be easily removed by polishing the surface of the particles. Therefore, when the core body 3 and the surface layer 5 are simultaneously formed, it is preferable to polish the surfaces thereof.

The polishing of the particle surface can be carried out by various methods. For example, EA, which is an inorganic / organic composite particle
The method can be performed by dispersing the particles 2 in a dispersion medium such as water and stirring this. At this time, a method of mixing an abrasive such as sand particles or balls into the dispersion medium and stirring with the EA particles 2, a method of stirring with a grinding wheel, or the like can be used. For example, it is also possible to dry-stir without using a dispersion medium, using the EA particles 2 and the above-mentioned abrasive or grinding stone.

A more preferable polishing method is a method in which the EA particles 2 are agitated by a jet stream or the like. This is a method of polishing particles by violently colliding with each other in a gas phase, and is a preferable method in that the polished particles can be easily separated by classification without the need for another abrasive. In the above jet stream agitation, it is necessary to select polishing conditions depending on the type of equipment used, the agitation speed, the material of the EA particles 2, etc., but generally 60
It is preferable to perform jet stream stirring at a stirring speed of 00 rpm for about 0.5 min to 15 min.

The ENC fluid composition of the present invention has the above EA
The particles 2 can be produced by uniformly stirring and mixing them in the electrically insulating medium 1 together with other components such as a dispersant, if necessary. As the stirrer, any stirrer normally used for dispersing solid particles in a liquid dispersion medium can be used.

As described above, according to the speaker system 32 of this embodiment, the variable power source 1 is used when listening to music.
A voltage is applied from 3 to the ENC fluid composition that constitutes the sound absorbing material 42, and the voltage value applied by turning the knob 43 is adjusted, and the frequency of the unnecessary sound output from the speaker 38 and reverberating unnaturally. By adjusting to, it is possible to extremely easily reduce the sound of that frequency, and to secure the optimum reproduction state of music or the like. Furthermore, even if the frequency of unnecessary sound that reverberates unnaturally changes depending on the room temperature, humidity, the number of people in the room, etc.
By rotating the knob 43 to change the applied voltage value, it is possible to match the changing frequency very easily.

Further, FIG. 14 shows a speaker system 32 of another embodiment. This speaker system 32 includes a speaker box 34 as well as a mounting table 35.
The front baffle plate 37 is also provided with the sound absorbing material 42. According to this speaker system 32, not only the sound output from the speaker 38 and reverberating unnaturally is reduced, but also the blur of the sound image is surely reduced, and the sense of localization caused by increasing the sound is deteriorated. Can be reliably prevented, and an extremely good tone color can be obtained. Further, as described above, instead of the structure in which the sound absorbing material 42 is attached to the front side of the front baffle plate 37 of the speaker box 34, the front baffle plate 37 itself may be formed by the sound absorbing material 42.

[0051]

As described above, according to the speaker system of the present invention, the following effects can be obtained. According to the speaker system of claim 1, a voltage is applied from the voltage applying means to the ENC fluid composition constituting the sound absorbing material, and the applied voltage value is adjusted so that the speaker body outputs the unnatural sound. By adjusting to the frequency of the unnecessary sound that resonates greatly, this unnecessary sound can be reduced, and the optimum reproduction state of music or the like can be secured. Further, even if the frequency of the unwanted sound that reverberates unnaturally changes due to the room temperature, humidity, the number of people in the room, etc., it can be changed very easily by changing the voltage value applied from the voltage applying means. The frequency at which the sound absorbing material can absorb sound can be changed according to the frequency. According to the speaker system of claim 2, since at least the sound absorbing material is provided on the front surface of the mounting table on the listener side, it is possible to surely eliminate the discomfort caused by the unnatural sound caused by the resonance of the mounting table. be able to. According to the speaker system of claim 3, since the vibration of the front plate to which the speaker is attached is reduced by the sound absorbing material, it is possible to reliably prevent the blur of the sound image due to the resonance of the front plate, which is excellent. A sense of localization can be secured.

[Brief description of drawings]

FIG. 1 is a front view of an audio system including a speaker system according to an embodiment of the present invention.

FIG. 2 is a side sectional view of a speaker system illustrating a configuration and a structure of the speaker system according to the embodiment of the invention.

FIG. 3 is a cross-sectional view of the speaker system illustrating the configuration and structure of the speaker system according to the embodiment of the invention.

FIG. 4 is a cross-sectional view of a sound wave absorption control device (sound control device) including the electro-sensitive type sound wave absorption control fluid composition.

FIG. 5 is a cross-sectional view showing a state in which a chain and one electrode plate resonate upon incidence of a sound wave in the sound wave absorption control device.

FIG. 6 is a cross-sectional view showing an example of the electro-sensitive sound wave absorption control fluid composition according to the present invention.

FIG. 7 is a cross-sectional view showing a mode of a fluid composition for electro-sensitive sound wave absorption control according to the present invention when the power is off.

FIG. 8 is a cross-sectional view showing a mode of the electro-sensitive acoustic wave absorption controlling fluid composition according to the present invention when the power is turned on.

FIG. 9 is a cross-sectional view showing a state where a sound wave is incident on the sound wave absorption control device and one of the electrode plates vibrates.

FIG. 10 is a graph showing the results of measuring the effect of electric field strength on electric field arrangement characteristics of an electric field arrangement particle dispersion system.

FIG. 11 is a diagram showing an equivalent circuit of a vibration system.

FIG. 12 is a diagram showing another example of the bending state of the chain in the sound wave absorption control device.

FIG. 13 is a diagram showing a column in which a plurality of chains are joined to each other in the sound wave absorption control device.

FIG. 14 is a side sectional view of a speaker system illustrating a configuration and structure of a speaker system according to another embodiment of the present invention.

[Explanation of symbols]

1 ... Electrically insulating medium, 2 ... EA particles (solid particles), 13
... Variable power source (voltage applying means), 32 ... Speaker system, 34 ... Speaker box (speaker body), 3
5 ... Mounting table, 37 ... Front baffle plate (front plate), 38 ... Speaker, 42 ... Sound absorbing material.

Front page continuation (72) Inventor Moritaka Goto 1-5-1, Kiba, Koto-ku, Tokyo, Fujikura Ltd. (72) Inventor Kenji Furuichi 1-1-5, Kiba, Koto-ku, Tokyo Fujikura Ltd. (72) Inventor Yasufumi Otsubo 206-1, Konakadai, Inage-ku, Chiba, Chiba 206

Claims (3)

[Claims] 1. A speaker system (32) comprising: a speaker body (34) having a front plate (37) provided with a speaker (38); and a mounting table (35) for mounting the speaker body (34). Therefore, the mounting table (35) contains a fluid composition for electro-sensitive sound wave absorption control in which solid particles (2) having an electric field array effect are contained in an electrically insulating medium (1). A sound absorbing material (42) and a voltage applying means (13) for applying a voltage to the electro-sensitive acoustic wave absorption controlling fluid composition constituting the sound absorbing material (42) and adjusting the applied voltage are provided. A speaker system characterized by becoming. 2. The sound absorbing material (42) is the mounting table (3).
The speaker system according to claim 1, wherein the speaker system is provided on at least the front surface of 5). 3. The speaker system according to claim 1, wherein the sound absorbing material (42) is provided on a front plate (37) provided with the speaker (38).