JP4875562B2 - Speaker device material and speaker device using the same - Google Patents

Description

  The present invention relates to an adsorbent material for a speaker device that can effectively realize bass reproduction in a small speaker device and has excellent moisture resistance, and a speaker device using the same.

  In general, in a small speaker device, since the volume of the speaker cabinet is small, it is difficult to reproduce low sound due to the effect of acoustic stiffness. That is, when an electrical signal is applied to the speaker, the air in the cabinet is compressed by the vibration of the speaker, and this acts as an air spring that prevents the speaker from moving. Regeneration cannot be achieved. In order to realize low-pitched sound reproduction in a small speaker device, a speaker device in which a gas adsorbing material such as activated carbon is arranged inside a cabinet has been proposed (for example, Patent Document 1).

  The speaker device of Patent Document 1 includes a speaker cabinet, a speaker attached to one surface of the cabinet such that a rear portion communicates with the interior of the cabinet, a gas contained in the cabinet, and an arrangement in the cabinet. Gas adsorbing material such as activated carbon. When an electrical signal is applied to the speaker, the vibration of the speaker causes the gas in the cabinet to be compressed and recovered at a high speed. Along with this, the gas molecules are adsorbed and desorbed on the activated carbon, so that the pressure fluctuation in the cabinet is suppressed. As a result, it is disclosed that the sound pressure level in the bass portion is not suppressed and the same effect as that obtained when a large-capacity cabinet is used can be obtained.

  The gas adsorbing material such as activated carbon desirably has a low water content. This is because when activated carbon adsorbs moisture, even if the gas in the cabinet is compressed by vibration of the speaker when placed in the cabinet, the ability to adsorb the gas molecules becomes insufficient. Therefore, in the above-mentioned Patent Document 1, a complicated configuration is adopted in which a partition wall (diaphragm) that does not allow moisture to pass between a speaker in a cabinet and a gas adsorbing material such as activated carbon is employed.

  In Patent Document 2, it is disclosed that an adsorbing material that is at least partially hydrophobized is used as a gas adsorbing material placed in a cabinet so that moisture is not easily adsorbed even in a high humidity atmosphere. Yes. For example, activated carbon hydrophobized by reaction with a silicon compound is disclosed. Patent Document 3 describes a hydrophobized activated carbon that can be used as such a gas adsorbing material. Such a material can be used even in a relatively high humidity atmosphere, but requires a complicated process of making it hydrophobic.

Patent Document 4 is a speaker device in which activated carbon is placed in a cabinet and the inside of the cabinet is replaced with high-concentration dry carbon dioxide gas, and further detecting means for detecting the internal carbon dioxide concentration, A loudspeaker apparatus is disclosed that has means for supplying carbon dioxide and means for controlling the supply. However, this speaker device also requires complicated means for keeping the humidity low.
JP-T-60-500635 Special table 2004-537938 gazette UK Patent Application Publication No. 2391224 International Publication No. 03/101147 Pamphlet

  The present invention solves the above-described conventional problems, and an object of the present invention is to realize low-frequency reproduction with a small speaker device more effectively and to achieve the effect even in a high humidity atmosphere. An object of the present invention is to provide an adsorbing material for a speaker device that can be sufficiently exerted, and a speaker device using the same.

  The inventors have found that activated carbon having a cumulative volume of pores having a radius in the range of 18 to 50 mm is 0.4 ml / g or more is difficult to adsorb moisture even in a relatively high humidity atmosphere. As a result, when the adsorbing material made of activated carbon is placed in the cabinet of the speaker device, the gas in the cabinet can be easily adsorbed and desorbed even in a relatively high humidity atmosphere. As a result, the present invention has been completed.

  The adsorbing material for a speaker device of the present invention is made of activated carbon having a radius of 18 to 50 cm and a cumulative pore volume of 0.4 ml / g or more.

  The speaker device of the present invention includes a cabinet, a speaker unit attached to the cabinet, and a speaker device adsorption material disposed in a vacant space inside the cabinet. The speaker device adsorption material has a radius of 18 It consists of activated carbon with a cumulative pore volume of ˜50 kg or more of 0.4 ml / g.

  According to an embodiment, the cumulative pore volume of the activated carbon having a radius of 18 to 50 mm is 0.5 ml / g or more.

  The activated carbon used for the adsorbing material for the speaker device of the present invention hardly adsorbs moisture even in a relatively high humidity atmosphere. Therefore, if this activated carbon is placed in the cabinet of the speaker device, even in a high humidity atmosphere, the pressure fluctuation of the gas in the cabinet caused by the vibration of the speaker is alleviated, and a sufficient bass reproduction effect can be obtained. Sound effects equivalent to those obtained when using a cabinet can be obtained.

(A) Adsorbing material for speaker device The activated carbon used for the adsorbing material for the speaker device of the present invention has a cumulative pore volume of 0.4 ml / g or more in a pore radius range of 18 to 50 mm. The cumulative pore volume in this range is preferably 0.5 ml / g or more. Activated carbon having such pore diameter characteristics has moisture resistance. Here, the activated carbon has “moisture resistance” means that when the activated carbon is left in an atmosphere of 30 ° C. and 70% relative humidity for 48 hours, the water adsorption amount per 1 g of the activated carbon is 200 mg or less. To tell. The water adsorption amount is preferably 100 mg or less.

  For this reason, when this activated carbon is placed in the cabinet of the speaker device, the amount of water adsorbed by the activated carbon is low even in an atmosphere of relatively high humidity. Therefore, adsorption and desorption of gas molecules in the cabinet can be sufficiently performed, and as a result, a sufficient bass reproduction effect can be obtained. Such an effect cannot be obtained when the cumulative pore volume in the range of the radius of the activated carbon pore of 18 to 50 mm is less than 0.4 ml / g.

  The cumulative pore volume of the activated carbon having a radius of 18 mm or less is preferably 0.2 ml / g or less, and more preferably 0.1 ml / g or less. When the cumulative pore volume with a radius of 18 mm or less exceeds 0.2 ml / g, the moisture adsorption amount tends to be relatively high in the region of 50 to 70% humidity, and a sufficient bass reproduction effect in the speaker device is obtained. It may not be possible.

  The pore radius and cumulative pore volume of the activated carbon defined above are measured by the water vapor method shown below. In this method, the equilibrium water vapor pressure of a sulfuric acid aqueous solution having a constant concentration becomes a constant value, that is, a predetermined relationship is established between the sulfuric acid concentration of the sulfuric acid aqueous solution and the equilibrium water vapor pressure. This space is created and measured using this. Specifically, the cumulative pore volume corresponding to a predetermined pore radius is obtained based on a curve indicating the relationship between the pore diameter and the cumulative pore volume created by the following method.

  A predetermined mass of activated carbon is placed in the gas phase portion of the adsorption chamber containing a sulfuric acid aqueous solution having a predetermined concentration, and brought into contact with water vapor at 48 ° C. for 48 hours under the conditions of 1 atm (absolute pressure) and 30 ° C. Next, the mass of the activated carbon is measured, and the mass increase is defined as the saturated adsorption amount of water of the activated carbon at 30 ° C.

  The sulfuric acid aqueous solution adopted above has an equilibrium water vapor pressure value (P) (1 atm (absolute pressure), a value at 30 ° C.) inherent to the concentration, and the water vapor pressure has a predetermined pore radius ( r) Water vapor is adsorbed in the pores having the following radii. The predetermined pore radius is obtained based on the Kelvin equation represented by the following equation (I). And the cumulative pore volume of pores below the pore radius corresponds to the volume of water at 30 ° C. corresponding to the saturated adsorption amount of water obtained by the above measurement.

r = − [2VmγcosΦ] / [RTln (P / P ₀ )] (I)
Where r, Vm, γ, Φ, R, T, P, and P ₀ have the following meanings:
r: pore radius (cm)
Vm: Molecular volume of water (cm ³ /mol)=18.079 ( ³⁰ ° C.)
γ: surface tension of water (dyne / cm) = 71.15 (30 ° C.)
Φ: Contact angle between the capillary wall and water (°) = 55 °
R: Gas constant (erg / deg · mol) = 8.3143 × 10 ⁷
T: Absolute temperature (K) = 303.15
P: saturated vapor pressure (mmHg) indicated by water in the pores
P ₀ : 1 atm (absolute pressure) of water, saturated vapor pressure (mmHg) at 30 ° C. = 31.824

  As the predetermined sulfuric acid aqueous solution, eleven types of sulfuric acid aqueous solutions having a specific gravity of 0.025 intervals from a specific gravity of 1.05 to 1.30, a sulfuric acid aqueous solution having a specific gravity of 1.35, and sulfuric acid having a specific gravity of 1.40. An aqueous solution (a total of 13 types of sulfuric acid aqueous solutions) is prepared, and the above measurement is performed. Thereby, in each measurement, the cumulative pore volume of pores not more than the calculated pore radius is obtained. By plotting the cumulative pore volume thus determined against the pore radius, a cumulative pore volume curve of activated carbon can be obtained. By differentiating this, a pore distribution curve is obtained. For example, FIG. 2 shows a graph showing the pore radius distribution of the activated carbon obtained in Example 1 and the cumulative pore volume with respect to the pore radius.

  Based on the cumulative pore volume curve of the activated carbon thus obtained, the cumulative pore volume of the activated carbon having a radius of 18 to 50 mm is obtained.

  The production method of the activated carbon used as the adsorbing material of the present invention is not particularly limited, and activated carbon having the predetermined cumulative pore volume may be selected from the activated carbons obtained by the usual activated carbon production method. Usually, the activated carbon used in the present invention is produced by sufficiently carbonizing a carbonaceous material and then activating it by a method such as gas activation or drug activation.

  As the carbonaceous material, mineral materials, plant materials, synthetic materials and the like are used. Examples of the mineral materials include coal / petroleum materials (coal pitch, coke, etc.). Examples of plant materials include wood, charcoal, fruit shells (coconut shells, etc.), and various fibers. Among these, various fibers include natural fibers such as cotton and hemp, regenerated fibers such as rayon and viscose rayon, and semi-synthetic fibers such as acetate and triacetate. Examples of the synthetic material include various synthetic resins. Examples thereof include polyamide resins such as nylon, polyvinyl alcohol resins such as vinylon, acrylic resins, polyacrylonitrile resins, polyolefin resins such as polyethylene and polypropylene. , Polyurethane resins, phenol resins, vinyl chloride resins, and the like.

  Of the carbonaceous materials, plant-based materials and mineral-based materials are particularly suitable. For example, coconut shells and coal materials are preferably used. Two or more kinds of carbonaceous materials may be mixed and used.

  The shape of the carbonaceous material is not particularly limited. Various shapes of materials such as granular, powder, fiber, and sheet can be used. For the purpose of handling and effective performance, granular carbonaceous materials are used for relatively large speaker devices, and fibrous or sheet-like carbonaceous materials are used for small and thin speaker devices. It is preferably used. The granular material may be crushed or granulated. Examples of the fibrous and sheet-like carbonaceous materials include sheet processed products such as woven fabric, non-woven fabric, film, felt, paper, and molded plate.

  The conditions for carbonizing the carbonaceous material are not particularly limited. For example, in the case of a granular carbonaceous material, conditions such as processing at a temperature of 300 ° C. or higher while flowing a small amount of inert gas through a batch rotary kiln are adopted. be able to.

  As described above, the activation method after carbonizing the carbonaceous material may employ any method such as gas activation and drug activation, but it has high mechanical strength and obtains activated carbon having the predetermined pore diameter. In terms of gas activation, gas activation is preferably employed. Examples of the gas used in the gas activation method include water vapor, carbon dioxide gas, oxygen, LPG combustion exhaust gas, or a mixed gas thereof. In consideration of safety and reactivity, a water vapor-containing gas (a gas containing 10 to 50% by volume of water vapor) is preferable.

  The activation temperature is usually 700 ° C to 1100 ° C, preferably 800 ° C to 1000 ° C. However, the activation temperature, time, and temperature rising rate are not particularly limited, and vary depending on the type, shape, size, desired pore size distribution, and the like of the carbonaceous material selected. Activated carbon obtained by activation can be used as it is, but in practice, it is preferable to remove the adhering component by acid washing, water washing or the like.

  The activated carbon thus obtained can be in the form of particles, powders, sheets, etc., depending on the shape of the carbonaceous material. Or you may grind | pulverize this further. As the particulate activated carbon, particles having a desired particle size can be used as needed from granular particles having a certain size to fine powders. The sheet-like activated carbon may be in the form of a fabric, felt, paper, plate or the like.

  The particle size of the activated carbon is usually 0.05 to 1.0 mm, preferably 0.1 to 0.3 mm. When the activated carbon is in the form of a fabric, the thickness is usually 0.1 to 2.0 mm, preferably 0.3 to 1.0 mm. An activated carbon fabric having a thickness of 0.1 mm or less is difficult to handle due to its low strength, and an activated carbon fabric having a thickness of 2.0 mm or more is difficult to produce. In the case of a felt shape, a paper shape, or a plate shape, the thickness is usually 0.1 to 10.0 mm, preferably 0.3 to 5.0 mm. In any of the above sizes, a particularly suitable bass reproduction effect can be obtained when used in a speaker device.

(B) Speaker Device The speaker device of the present invention will be described with reference to FIG. The speaker device 1 of the present invention includes a cabinet 10, a speaker unit 11 attached to the cabinet, and a speaker device adsorption material 12 disposed in a vacant space R inside the cabinet. This speaker device is a bass reflex type speaker device having a bass reflex port 101 in a cabinet 10. The method of the speaker device of the present invention is not particularly limited, and may be a sealed speaker device.

  The speaker device adsorption material 12 is made of activated carbon having the predetermined cumulative pore volume. When the activated carbon is in the form of a fiber or a sheet, it can be placed in an appropriate place in the empty room R in the cabinet as it is. In the case of granular or powdered activated carbon, it is preferable that the activated carbon is packaged with a wrapping material having air permeability such as a woven fabric or a non-woven fabric and disposed in the cabinet. The amount of the speaker device adsorption material 12 varies depending on the capacity of the cabinet, the shape of the activated carbon, and the like, and is not particularly limited.

  The speaker device in FIG. 1 is a bass reflex speaker device having a bass reflex port (acoustic port) 101 in a cabinet 10. In the bass reflex system, the sound radiated to the back surface of the speaker unit is adjusted by adjusting the size and length of the opening of the bass reflex port so as to be acoustically resonated with the volume of the vacant space R, and the sound in the low frequency region is extracted. The purpose is to increase the pressure. Since this bass reflex port enables the circulation of air inside and outside the cabinet, the humidity inside the cabinet increases when the humidity of the outside air is high. The activated carbon used in the present invention has sufficient moisture resistance since the cumulative pore volume with a radius of 18 to 50 mm is 0.4 ml / g or more. Therefore, even if the speaker device is used in a high humidity atmosphere, it is difficult for moisture to be adsorbed on the activated carbon.

  In FIG. 1, when an electric signal is applied to the speaker unit 11, a force is generated in the voice coil, and the cone-type diaphragm is vibrated to generate sound. The sound pressure generated by the cone-shaped diaphragm increases the internal pressure of the empty room R. However, because the speaker device adsorbing material 12 made of moisture-resistant activated carbon is disposed in the vacant space R, the activated carbon gas can be adsorbed and desorbed effectively even under high humidity. As a result, the pressure fluctuation in the empty room R is suppressed, and the empty room R has an equivalently large volume. As a result, a sufficient bass reproduction effect can be obtained, and an acoustic effect equivalent to that obtained when a large-capacity cabinet is used can be obtained.

Example 1
Coal was granulated to obtain a carbide, which was activated with a steam-containing combustion gas at 880 ° C. and then pulverized to obtain granular activated carbon having an average particle size of 0.35 mm. The cumulative pore volume curve of this activated carbon is shown in FIG. 2 together with the pore distribution curve. In FIG. 2, a1 is a cumulative pore volume curve, and b1 is a pore distribution curve. The value on the vertical axis of the cumulative pore volume curve a1 indicates the cumulative pore volume (ml / g) per gram of activated carbon. The vertical axis of the pore distribution curve b1 represents a relative value. The same applies to a2 and b2 in FIG. The cumulative pore volume of this activated carbon having a radius of 18 to 50 mm was 0.62 ml / g.

  A graph showing the amount of water adsorbed per gram of activated carbon (g) relative to the relative humidity is shown in FIG. This graph is a graph created from the relative humidity and the amount of water adsorbed corresponding to the relative humidity calculated from the water vapor pressure corresponding to various sulfuric acid concentrations in the water vapor method. In FIG. 4, the unit of the vertical axis (g / g-AC) indicates the amount of water adsorbed per 1 g of activated carbon.

(Example 2)
Coal was granulated to obtain a carbide, which was activated with a steam-containing combustion gas at 900 ° C. to obtain granular activated carbon having an average particle size of 0.32 mm. The cumulative pore volume of this activated carbon having a radius of 18 to 50 mm was 0.71 ml / g. For this activated carbon, a graph of the amount of water adsorption similar to that in Example 1 is shown in FIG.

(Comparative Example 1)
The coconut shell was carbonized to obtain a carbide, which was activated with a steam-containing combustion gas at 850 ° C. to obtain granular activated carbon having an average particle size of 0.35 mm. The cumulative pore volume curve a2 of this activated carbon is shown in FIG. 3 together with the pore distribution curve b2. The cumulative pore volume of this activated carbon having a radius of 18 to 50 mm was 0.03 ml / g. For this activated carbon, a graph of the amount of water adsorption similar to that in Example 1 is shown in FIG.

(Comparative Example 2)
The phenol resin fiber was carbonized to obtain a carbide, which was activated with a steam-containing combustion gas at 850 ° C. to obtain cloth-like activated carbon having an average thickness of 0.50 mm. The cumulative pore volume of this activated carbon having a radius of 18 to 50 mm was 0.00 ml / g. For this activated carbon, a graph of the amount of water adsorption similar to that in Example 1 is shown in FIG.

(Example 3)
The speaker device shown in FIG. 1 was prepared. This speaker device is a bass-reflex speaker device in which a cone-type speaker unit 11 having a diameter of 8 cm is attached to a cabinet 10 having an internal volume of 0.8 L provided with a bass-reflex port 101. In the vacant space R of the speaker device, 40 g of activated carbon obtained in Example 1 was packaged and placed on a breathable woven fabric as the speaker device adsorption material 12.

  A 1 W sine wave electric input was applied to the speaker unit, a measurement microphone was placed at a position 1 m away from the speaker device, and the sound pressure was measured. As a control, the same measurement was performed on a speaker device on which no activated carbon was placed.

  Next, the speaker device having the activated carbon was left in an atmosphere of 70% humidity for 24 hours. After leaving, the sound pressure of the speaker device having activated carbon was measured in the same manner.

  A curve 21 in FIG. 5 is a curve (frequency response curve) showing a sound pressure characteristic of the speaker device at the beginning of the production in this embodiment, and a curve 22 is after the speaker device is left in an atmosphere of 70% humidity for 24 hours. It is a frequency response curve. Curve 23 is the frequency response curve of the control speaker device. The curve 21 shows a higher sound pressure level in the low frequency region of 30 to 100 Hz than the curve 23, and it can be seen that the low sound is reproduced well. Further, the curve 22 showing the sound pressure characteristics after being left in an atmosphere with a humidity of 70% is almost the same as the curve 21, and it can be seen that a sufficiently high sound pressure level can be obtained in the low sound region even under high humidity.

(Comparative Example 3)
The test was performed in the same manner as in Example 3 except that the activated carbon obtained in Comparative Example 1 was used in place of the activated carbon obtained in Example 1 in the same apparatus as in Example 3.

  A curve 31 in FIG. 6 is a frequency response curve of the speaker device at the beginning of production in this comparative example, and a curve 32 is a frequency response curve after leaving the speaker device in an atmosphere of 70% humidity for 24 hours. Curve 33 is the frequency response curve of the control speaker device. The curve 31 shows a higher sound pressure level in the low frequency region of 30 to 100 Hz than the curve 33, and it can be seen that the bass is reproduced well. However, the portion in the frequency region of the curve 32 showing the sound pressure characteristics after being left in an atmosphere with a humidity of 70% approximates the control curve 33, and a high sound pressure level in the low sound region under high humidity. It is clear that it cannot be obtained.

  Since the adsorbing material for a speaker device of the present invention is made of activated carbon having a predetermined pore volume characteristic, it has high moisture resistance. When this adsorbing material is placed in the cabinet of the speaker device, the pressure fluctuation of the gas in the cabinet caused by the vibration of the speaker is effectively suppressed even in a high humidity atmosphere. As a result, an acoustic effect equivalent to that of a speaker device using a large capacity cabinet can be obtained. The adsorbing material for a speaker device of the present invention can be used favorably for both sealed and bass-reflex speaker devices, and a speaker device having a good bass reproduction effect even in a high humidity atmosphere can be obtained.

It is a schematic cross section which shows one example of the speaker apparatus using the adsorption material for speaker apparatuses of this invention. It is a graph which shows the pore radius distribution of the activated carbon obtained in the Example of this invention, and the cumulative pore volume with respect to a pore radius. It is a graph which shows the pore radius distribution of the activated carbon obtained by the comparative example of this invention, and the cumulative pore volume with respect to a pore radius. It is a graph which shows the water adsorption amount with respect to relative humidity of the activated carbon obtained by the Example and comparative example of this invention. It is a graph which shows the curve which shows the sound pressure characteristic when the speaker apparatus manufactured in the Example of this invention and it was left to stand under high humidity. It is a graph which shows the curve which shows the sound pressure characteristic when the speaker apparatus manufactured by the comparative example of this invention and it was left to stand under high humidity.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Speaker apparatus 10 Cabinet 11 Speaker unit 12 Adsorption material for speaker apparatuses 101 Bass reflex port

Claims (4)

  An adsorbing material for a speaker device, comprising activated carbon having a radius of 18 to 50 cm and a cumulative pore volume of 0.4 ml / g or more.   The adsorbent material for a speaker device according to claim 1, wherein a cumulative pore volume of the activated carbon having a radius of 18 to 50 mm is 0.5 ml / g or more. A speaker device having a cabinet, a speaker unit attached to the cabinet, and a speaker device adsorbing material disposed in an empty room inside the cabinet,
The speaker device adsorption material is a speaker device made of activated carbon having a radius of 18 to 50 cm and a cumulative pore volume of 0.4 ml / g or more.   The speaker device according to claim 3, wherein a cumulative pore volume of the activated carbon having a radius of 18 to 50 mm is 0.5 ml / g or more.

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