JP4354887B2 - Tandem-driven speaker device and its structure - Google Patents

Description

  The present invention relates to a tandem drive type speaker device in which two speaker units are arranged back to back in opposite directions and driven in the same phase, and a structure thereof.

  For example, in Patent Document 1, an acoustic space is formed on the rear surface of a diaphragm attached to a cabinet in order to reduce mechanical vibration generated from a speaker unit during sound emission and to improve sound quality by reducing mechanical vibration of the cabinet. The first speaker unit that emits sound from the front surface of the diaphragm by the supplied driving signal and the second speaker unit fixed back to back with the driving signal in a direction opposite to the vibration direction of the diaphragm of the first speaker unit A speaker system (hereinafter referred to as a first conventional example) including a second speaker unit that vibrates a diaphragm in an acoustic space formed by a cabinet is disclosed. In the first conventional example, two mechanical units are operated in the same phase and their back surfaces are fixed to cancel two mechanical vibrations in opposite directions.

  Further, in Non-Patent Document 1, in order to enhance bass, a tandem drive type speaker device (in which a two-unit speaker unit is placed in a reverse direction and back-to-back driven in the same phase in a rectangular cylindrical sealed casing ( Hereinafter, a production article of the second conventional example) is disclosed.

Japanese Patent Laid-Open No. 10-178893. JP2003-092793A. Takahisa Ozawa, “Production of Fostex FE83 × 2 Tandem Drive System”, Audio Craft Magazine, No. 2, MJ Radio and Experimental Editing, pp. 35-39, issued in October 2001.

  In the first conventional example, since the inertia is controlled by fixing the back surfaces of the two speaker units, there is a problem that the sound pressure is lowered and the lowest resonance frequency of the speaker device cannot be lowered. There was a point.

  In the second conventional example, since two speaker units are arranged back to back in a rectangular cylindrical sealed casing, the sound waves generated by the two speaker units are coupled. Disturbances and deterioration of sound quality occurred, and there was a problem that the bass could not be strengthened because it was a small device.

  An object of the present invention is to provide a tandem drive speaker device and a structure thereof that can solve the above-described problems and that can lower the minimum resonance frequency of the speaker device and suppress deterioration in sound quality as compared with the conventional example. is there.

The tandem drive type speaker device according to the first aspect of the present invention includes two speaker units which are spaced apart from each other by a predetermined distance at one end and one speaker unit is disposed outward, and the other end is sealed. A tandem drive type speaker device that includes a cylindrical tube housing and that electrically drives the two speaker units in substantially opposite phases so that sound wave vibrations are substantially in phase with each other,
In the speaker unit coupling portion in which the two speaker units are disposed, a first tubular tube provided so as to surround the magnets of the two speaker units;
In the sound wave processing section between the speaker unit coupling section and the other end of the cylindrical housing, the longitudinal direction of each tubular tubule is substantially parallel to the longitudinal direction of the cylindrical casing in the cylindrical casing. A plurality of second tubular tubules for maintaining a sound wave substantially contained in a plane wave when housed and exciting the two speaker units;
A reflection suppressing portion provided at the other end of the cylindrical housing and substantially suppressing the sound wave radiated into the cylindrical housing from being reflected at the other end of the cylindrical housing; Features.

  In the tandem drive type speaker device, the two speaker units are accommodated in the speaker unit coupling portion so that the longitudinal direction of each tubular tubule is substantially parallel to the longitudinal direction of the tubular housing. A plurality of third cylindrical capillaries are further provided for maintaining a sound wave radiated into the cylindrical housing when the unit is excited in a substantially plane wave.

  Further, in the tandem drive type speaker device, the reflection suppressing portion is formed in a conical shape with a vertex facing the two speaker units, and a pyramid disposed with a vertex facing the two speaker units. It has a shape or an oblique cut shape.

  Furthermore, in the tandem drive type speaker device, the reflection suppressing portion includes a sound wave absorbing layer that absorbs sound waves on a surface thereof.

  Furthermore, the tandem drive type speaker device further includes a sound absorbing material provided between each of the tubular tubes and the cylindrical housing.

  Furthermore, the tandem drive type speaker device further comprises a high-frequency range reproduction speaker provided on the front surface of one of the two speaker units disposed outward. To do.

The structure of the tandem drive type speaker device according to the second aspect of the invention comprises two speaker units, one speaker unit being disposed at one end and spaced apart from each other by a predetermined distance, with the other end sealed. And a tandem drive type speaker device that drives the two speaker units electrically in opposite phases so that sound wave vibrations are substantially in phase with each other. And
In the speaker unit coupling portion in which the two speaker units are disposed, a first tubular tube provided so as to surround the magnets of the two speaker units;
In the sound wave processing section between the speaker unit coupling section and the other end of the cylindrical housing, the longitudinal direction of each tubular tubule is substantially parallel to the longitudinal direction of the cylindrical casing in the cylindrical casing. A plurality of second tubular tubules for maintaining a sound wave substantially contained in a plane wave when housed and exciting the two speaker units;
A reflection suppressing portion provided at the other end of the cylindrical housing and substantially suppressing the sound wave radiated into the cylindrical housing from being reflected at the other end of the cylindrical housing; Features.

  In the structure of the tandem drive type speaker device, the speaker unit coupling portion is accommodated in the tubular housing so that the longitudinal direction of each tubular tubule is substantially parallel to the longitudinal direction of the tubular housing. And a plurality of third tubular tubes for maintaining a sound wave radiated into the cylindrical housing substantially as a plane wave when the speaker unit is excited.

  Further, in the structure of the tandem drive type speaker device, the reflection suppressing portion is arranged in a conical shape in which the vertex faces the two speaker units, and the vertex faces the two speaker units. It has a pyramid shape or an oblique cut shape.

  Furthermore, in the structure of the tandem drive type speaker device, the reflection suppressing portion includes a sound wave absorbing layer for absorbing sound waves on the surface thereof.

  Furthermore, the structure of the tandem drive type speaker device is characterized by further comprising a sound absorbing vibration damping material provided between each of the tubular thin tubes and the cylindrical casing.

  Furthermore, the structure of the tandem drive type speaker device further comprises a high-frequency range reproduction speaker provided on the front surface of one of the two speaker units arranged outward. Features.

  Therefore, according to the tandem drive type speaker device and the structure thereof according to the present invention, the sound wave radiated into the cylindrical casing is substantially reflected by the other end of the cylindrical casing by the reflection suppressing portion. And suppressing the sound wave propagating in the speaker unit coupling portion and the sound wave processing portion to the inside of the cylindrical housing by the first tubular tubule and the plurality of second tubular tubules. It can be maintained in a substantially plane wave. As a result, the lowest resonance frequency in the tandem drive type speaker device can be drastically reduced to improve the low frequency characteristics, and the increase in the sound pressure of the overall frequency characteristics in the tandem drive can be reproduced with the original sound faithfully reproduced. realizable.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected about the same component.

First embodiment.
FIG. 1 is a partially broken perspective view showing a structure of a tandem drive type speaker device according to a first embodiment of the present invention. 2 is a longitudinal sectional view taken along line AA ′ in FIG. 1, FIG. 3 is a transverse sectional view taken along line BB in FIG. 2, and FIG. 4 is taken along line CC ′ in FIG. It is a cross-sectional view. The tandem drive speaker device according to the present embodiment is
(A) Two lower end portions are provided on the upper portion of the cylindrical housing 2 sealed by the housing base portion 3 and are spaced apart from each other by a predetermined distance back to each other, and one speaker unit is disposed outward. A speaker unit coupling unit 101 including speaker units 1 and 51 (external speaker unit 1 and internal speaker unit 51, hereinafter referred to as a speaker unit);
(B) In the speaker unit coupling portion 101, a cylindrical thin tube 40 provided so as to surround the magnets 1b and 51b of the two speaker units 1 and 51;
(C) In the speaker unit coupling portion 101, a plurality of cylindrical thin tubes 30 provided in a space between the cylindrical thin tube 40 and the cylindrical housing 2,
(D) Provided in an intermediate portion of the cylindrical casing 2 located between the speaker unit coupling portion 101 and the lower end of the cylindrical casing 2, and the longitudinal direction of each tubular tube 20 in the cylindrical casing 2 is the cylindrical casing 2. A plurality of units that are accommodated so as to be substantially parallel to the longitudinal direction, and that maintain the sound waves radiated inside the cylindrical housing 2 as substantially plane waves when the two speaker units 1 and 51 are excited. A sonication unit 102 including a cylindrical tube 20;
(E) a cone-shaped reflection suppressing portion 4 provided at the lower end of the cylindrical housing 2 and substantially suppressing reflection of sound waves radiated into the cylindrical housing 2 at the lower end of the cylindrical housing 2; With
(F) The two speaker units 1 and 51 are electrically driven in substantially opposite phases so that the sound wave vibrations are substantially in phase with each other.

  Next, the configuration of the tandem drive type speaker device according to the present embodiment will be described below with reference to FIGS.

  As shown in FIGS. 1 and 2, a speaker provided with a diaphragm 1a and a magnet 1b so that a sound wave from the front surface of the diaphragm from the speaker unit 1 is radiated upward at one upper end of the cylindrical housing 2. The unit 1 is fixed to the mounting ring 2a. Further, the speaker unit 1 is back-to-back, and is spaced below the speaker unit 1 so that the magnets 1b and 51b face each other at a predetermined interval, preferably close to the magnet unit 1b. A speaker unit 51 including a plate 51a and a magnet 51b is provided. That is, the speaker unit 51 is provided in a direction opposite to that of the speaker unit 1 so that the front surface of the diaphragm is directed inward. The distance between the two speaker units 1 and 51 is preferably as close as possible as described above, but the reason is to reduce the vibration time as much as possible. This is particularly important when the full-range speaker units 1 and 51 are used for playback up to the super-high frequency range. However, even when dedicated to the low frequency range, it cannot be ignored in order to obtain high-speed playback sound with high dynamics. It is.

  These two speaker units 1 and 51 constitute a speaker unit coupling unit 101. The two speaker units 1 and 51 are preferably the same speaker unit. This is to make the vibration characteristics of the speaker units 1 and 51 as equal as possible, prevent the occurrence of amplitude distortion and phase shift due to interference of different kinds of vibrations, and improve the fidelity of waveform reproduction. In addition, the inner diameter of the cylindrical housing 2 is physically made as equal as possible to the outer diameters of the speaker units 1 and 51. This is to prevent the generation of spreading sound waves, that is, spherical waves. Furthermore, the mounting hole diameter of the baffle to which the speaker unit 1 is attached is set to the minimum diameter to which the speaker unit 1 can be attached, and the mounting hole has a tapered shape that linearly extends downward. This is because the flow of the sound wave radiated from the speaker unit 1 toward the lower end is not obstructed, and the collapse of the plane wave (particularly, the collapse in the high region where the wavelength is short) due to a sudden change in the cross section is suppressed as much as possible. .

  In the speaker unit coupling portion 101, as shown in FIGS. 2 and 3, a sound absorbing material 14 is attached to the inside of the cylindrical housing 2 and surrounds the magnets 1b and 51b of the speaker units 1 and 51. The cylindrical thin tube 40 is provided so that the longitudinal direction of the cylindrical thin tube 40 is substantially parallel to the longitudinal direction of the cylindrical housing 2, and the cylindrical thin tube 40 is disposed in the space between the cylindrical thin tube 40 and the sound absorbing material 14. For example, seven cylindrical capillaries 30 are provided so that the longitudinal direction of 40 is substantially parallel to the longitudinal direction of the cylindrical housing 2. Thus, a space 30a of a propagation path of sound waves generated when the speaker units 1 and 51 are driven is formed. Here, the cylindrical thin tubes 30 and 40 are provided in order to propagate sound waves generated when the speaker units 1 and 51 are driven in a direction substantially parallel to the longitudinal direction of the cylindrical housing 2. In order to increase the fidelity of the high-frequency sound wave coupling of the full-range speaker units 1 and 51, the cylindrical thin tube 30 is inserted in the speaker unit coupling portion 101. The diameter of the cylindrical thin tube 30 is, for example, high-frequency sound wave When the frequency is 10,000 Hz, 34400 cm / 10000 Hz = 3.4 cm or less. The cylindrical thin tube 40 may be used as a donut-shaped enclosure instead of the cylindrical thin tube 30 and is suitable for a large mid-bass speaker having a low high frequency limit.

  Further, in the sound wave processing unit 102, as shown in FIGS. 1 to 3, a sound absorbing material 13 is affixed to the inside of the cylindrical housing 2, and in the space inside the sound absorbing material 13, the longitudinal direction of the cylindrical thin tube 20. For example, seven cylindrical capillaries 20 are provided so that the direction thereof is substantially parallel to the longitudinal direction of the cylindrical housing 2, and thereby, the propagation path of the sound wave generated when the speaker units 1, 51 are driven. Spaces 20a and 21 are formed. Here, the cylindrical thin tube 20 is provided in order to propagate sound waves generated when the speaker units 1 and 51 are driven in a direction substantially parallel to the longitudinal direction of the cylindrical housing 2.

  The inner peripheral surface and the outer peripheral surface of each of the cylindrical capillaries 20, 30 and 40 are preferably smooth surfaces in order to make the progress of the plane wave smooth, that is, not disturb the progress. In consideration of the traveling wave, which is a plane wave, traveling in the inner peripheral surface of each cylindrical thin tube 20, 30, 40, the outer peripheral surface may be a rough surface to some extent. Further, it is necessary to absorb the reflected wave or standing wave incident substantially perpendicularly (horizontal direction, that is, lateral direction) to the inner peripheral surface and outer peripheral surface of each of the cylindrical thin tubes 20, 30, 40. Therefore, it is preferable to form each cylindrical tubule 20, 30, 40 with a material that easily converts the acoustic energy into heat energy. Specifically, the paper of the material entangled with the fibers is wound three to five times. A thing (it may be single winding or double winding) is used, and the sound absorption property with respect to a reflected wave or a standing wave is given. As the paper of the above-mentioned material, for example, drawing paper made by Daishowa Paper (125 kg / 1000 sheets in 46 plates; for example, thickness of 0.2 to 0.3 mm) is suitable. Alternatively, each of the cylindrical thin tubes 20, 30, 40 may have a structure in which a multi-wrapped paper is surrounded by a single closed paper tube, and other materials can be used as long as they have equivalent performance. But you can. In addition, each cylindrical thin tube 20, 30, 40 is not limited to a cylindrical shape, and may be a cylindrical shape such as a rectangular cylindrical shape. The sound absorbing materials 13 and 14 are made of paper tubes of the cylindrical thin tubes 20, 30, and 40, or felt or micron wool.

  Further, the lower end of the cylindrical housing 2 is sealed by a housing base portion 3, and the housing base portion 3 is used as a support member for standing the apparatus. Between the housing base portion 3 and the sound wave processing portion 102, for example, a conical reflection suppressing portion 4 is formed on the housing base portion 3 so that the apex thereof faces the speaker unit 51. The reflection suppressing portion 4 is made of, for example, balsa wood or a resin molding material, and includes a conical circumferential surface 4a and a conical bottom surface 4b as shown in FIG. On the conical circumferential surface 4a, two acoustic wave absorbing layers 5 and 6 made of, for example, felt and micron wool are formed. Furthermore, it is preferable to fill the inside of the reflection suppressing unit 4 with sand or zircon sand in order to suppress vibration, absorb sound waves, and lower the center of gravity. As an alternative, only an effect of absorbing sound waves can be expected, but a method of compressing and filling coarse wool felt, carbon fiber, micron wool, or the like may be used.

  Here, the apex angle of the cone of the reflection suppressing unit 4 is preferably set to 60 ° to 100 °, and when the angle becomes sharper than the above value, the speaker unit coupling due to the decrease in the volume of the speaker unit coupling unit 101 and the sound wave processing unit 102. An increase in the minimum resonance frequency of the portion 101 becomes obvious. On the other hand, when the angle becomes obtuse, the reflected wave in the vertical direction becomes obvious. Moreover, although it is preferable that the space | interval of the vertex of the reflection suppression part 4 and the cylindrical thin tube 20 located in the center part is more than a predetermined space | interval, the cylindrical thin tube 20 located in the vertex of the reflection suppression part 4 and the center part is preferable. May not be in contact with each other, the apex of the reflection suppressing portion 4 may be located inside the cylindrical thin tube 20 located in the central portion. Further, the bottom diameter of the reflection suppressing unit 4 is approximated to the inner diameter of the cylindrical housing 2 as much as possible. Further, the inner diameter of the cylindrical housing 2 is approximated to the outer diameter of the speaker units 1 and 51.

  The role of the material of the cylindrical thin tubes 20, 30, and 40 and the reflection suppressing portion 4 at the lowermost end of the cylindrical housing 2 in the tandem drive type speaker device configured as described above will be described below.

  The wall surfaces of the cylindrical capillaries 20, 30, 40 pass through the resonance energy of the sound wave having a wavelength shorter than the diameter reflected in the diameter direction of the two cylindrical housings when passing through the paper tube wall intertwined with the fibers as the wall surface material. It converts to heat energy by fiber friction and plays a role of attenuating sonic energy. Therefore, the paper material suitable for the material of the cylindrical capillaries 20, 30, 40 has a semiconductor characteristic of sound waves that absorbs 20 to 50% of the sound waves in the diameter direction and transmits about 50 to 80% at the same time due to friction of the paper fibers. Things are desirable. The diametrical sound wave in the cylindrical housing 2 attenuates the resonance energy to a level that can be ignored in practice by penetrating a plurality of the paper materials. In addition, the vertical sound wave (plane wave) that intersects the diametrical direction at right angles can be transmitted through the cylindrical thin tubes 20, 30, 40 without any resistance. For this reason, the inner wall surfaces of the cylindrical capillaries 20, 30, and 40 are arranged to be on the smooth surface side of the paper material. In this way, the thin wall material of each cylindrical thin tube 20, 30, 40 is made into a paper tube of a semiconductor character because the length of the paper tube is 1/4 wavelength, and its integral multiple This is to weaken the tube resonance of the sound wave. As the paper material, for example, Maruman's thick watercolor drawing paper S322N (neutral paper) is suitable. The cylindrical thin tubes 20, 30, and 40 wind the paper material in a single layer or a triple layer and bond the winding ends. The number of turns is determined by cutting and trying according to the participation rate and hearing of the air described above. In addition, a sound absorbing material is disposed in the lowermost open portion of the paper tube to absorb the sound wave reflection energy, and at the same time, the direction axis of the sound wave that is reflected without being completely absorbed is obliquely shifted from the vertical direction (plane wave). The conical reflection suppressing portion 4 is disposed at the lowermost end of the cylindrical housing 2.

  Moreover, in the tandem drive type speaker device according to the present embodiment, the bottom bottom surface of the cylindrical housing 2 is completely sealed for the following reason. That is, the so-called tube resonance type in which the lower end of the cylindrical housing 2 is opened, and the bass reflex type speaker device in which the bass is enhanced by resonance of Helmholtz are accompanied by unnaturalness peculiar to resonance in the reproduced sound, and the case is opened. Internal noise leaks from the hole, causing the sound quality to deteriorate. In the present embodiment, in order to prevent the above phenomenon, the cylindrical housing 2 is made to be a completely sealed type, and the rise of the minimum resonance frequency, which is a drawback of the sealed type, is maintained as a plane wave using the cylindrical thin tubes 20, 30, and 40. It is solved by the structure. With the above structure, sound waves radiated from the rear surface of the diaphragm of the speaker unit 1 and the front surface of the diaphragm of the speaker unit 51 are radiated only as a plane wave downward, so that the bottom surface at the lower end of the cylindrical housing 2 receives. The pressure of the sound wave becomes higher in inverse proportion to the surface area ratio in the housing than the sound pressure on the rear surface of the housing of the conventional speaker device that emits spherical waves. Therefore, in the present embodiment, the reflection suppressing unit 4 is provided at the bottom of the cylindrical housing 2. Moreover, by filling the inside of the reflection suppressing part 4 with sound absorbing materials such as felt and micron wool, and vibration suppressing materials such as sand and zircon sand, unnecessary sound wave energy can be converted into heat energy and lost. Therefore, it is possible to efficiently suppress and reduce noise in the cylindrical housing 2. Furthermore, unnecessary noise can be absorbed by forming the sound wave absorbing layers 5 and 6 on the surface excluding the bottom surface of the reflection suppressing portion 4, and the collapse of the plane wave in the cylindrical housing 2 can be reduced.

  In the tandem drive type speaker device configured as described above, the two speaker units 1 and 51 are electrically driven in substantially opposite phases so that the sound wave vibrations are substantially in phase with each other. Thereby, a plane wave of a substantially in-phase sound wave is formed in the cylindrical housing 2 and propagated by the two speaker units 1 and 51.

  As described above, according to this embodiment, when the two speaker units 1 and 51 are electrically driven in substantially opposite phases so that the sound wave vibrations are substantially in phase with each other, each speaker unit 1 and 51 are generated substantially synchronously in the cylindrical housing 2, and the generated sound waves are substantially held as plane waves by the cylindrical thin tubes 20, 30 and 40, and the tube diameter A sound wave having a shorter wavelength is suppressed from being reflected by the tube wall, and the plane wave is processed so as not to be reflected upward by the reflection suppressing unit 4 at the lower end of the cylindrical housing 2. , 51 is configured to increase the amount of air moving together with the diaphragm. The cylindrical housing 2 is hermetically sealed so that sound waves generated in the cylindrical housing 2 do not completely leak out of the cylindrical housing 2, and noise is not generated by vibration of the cylindrical housing 2 itself. Yes. As a result, the lowest resonance frequency in the tandem drive type speaker device can be drastically reduced to improve the low frequency characteristics, and the increase in the sound pressure of the overall frequency characteristics in the tandem drive can be reproduced with the original sound faithfully reproduced. realizable.

  In the above embodiment, the cylindrical thin tube 30 is provided, but the present invention is not limited to this and may not be provided.

Second embodiment.
5 is a partially broken perspective view showing the structure of the tandem drive type speaker device according to the second embodiment of the present invention, FIG. 6 is a top view of the tandem drive type speaker device of FIG. 5, and FIG. It is a longitudinal cross-sectional view of the upper part of the tandem drive type | mold speaker apparatus of FIG. Compared with the tandem drive type speaker device of FIG. 1, the tandem drive type speaker device according to this embodiment is provided with (A) a speaker 61 for high-frequency reproduction called a tweeter on the front surface of the speaker unit 1, and (B ) It is characterized in that the cylindrical thin tube 40 is not provided. In the present embodiment, the cylindrical thin tube 40 is not provided, but may be provided in the same manner as in the first embodiment. Hereinafter, the difference will be described.

  6 and 7, the high-frequency range reproduction speaker 61 is attached on the central axis of the cylindrical housing 2 to a blanket 70 having a plurality of sound wave holes 70h via a sorbocein 61s that is a vibration absorbing material. Here, the blanket 70 is fixed to the mounting portion 2a of the frame outer edge portion of the mid-bass diaphragm 1a of the speaker unit 1 with a screw 73 through a sorbocein 71. Further, a felt 62 is provided below the high-frequency range reproduction speaker 61 for absorbing sound and suppressing sound pressure from the midbass. As described above, by attaching the high frequency range reproduction speaker 61, the influence of the mechanical vibration and the sound pressure vibration generated by the mid bus of the speaker unit 1 on the high frequency range reproduction speaker 61 is suppressed as much as possible, and the Doppler effect is achieved. Prevent occurrence.

  In the present embodiment, in particular, in a large tandem drive type speaker device, in order to reproduce a large volume, a high frequency range reproduction speaker 61 is added, and the large speaker unit 1 is used for the midbass. By providing a plane wave maintaining mechanism such as the cylindrical thin tube 20 as described above, it is possible to effectively utilize the air weight and obtain a sufficiently large low-frequency energy. Here, as shown in FIG. 7, the additional mechanism of the high-frequency range reproduction speaker 61 is attached to the high-frequency range reproduction speaker 61 so as to be close to the midbass speaker unit 1 and coaxial with the cylindrical housing 2. Consideration is made so that the reproduced sound wave is synthesized with naturalness by operating in the full range mode while using the two speaker units 1 and 51. In order to bring out the naturalness of the full-range mode described above, select a mid-bass loudspeaker unit 1 that has excellent mid- and high-frequency characteristics (characteristics in which the sound pressure decreases toward the high frequencies), and network the amplifier output. It is preferable to supply straight without going through. Furthermore, the crossover frequency of the high-frequency range reproduction speaker 61 is selected so that the high-frequency range reproduction speaker 61 compensates for the shortage of the high frequency range in the midbass speaker unit 1, and at the same time, the optimum attenuation characteristic is determined. Yes. Since the speaker device according to the present embodiment has omnidirectional characteristics in the horizontal direction (strictly, in the same horizontal plane), the unnaturalness of the aerial synthesis of sound waves emitted by the two speaker units 1 and 51 is not noticeable. Yes.

  According to the embodiment configured as described above, the sound pressure in the high sound range is increased by the added high sound range reproduction speaker 61, and the lowest resonance in the tandem drive type speaker device as in the first embodiment. The frequency characteristics of the low frequency range can be improved by drastically reducing the frequency, and an increase in the sound pressure of the entire frequency characteristics in tandem driving can be realized in a state where the original sound is faithfully reproduced.

Modified example.
FIG. 8 is a perspective view showing the structure of the oblique cut type reflection suppressing portion 4A according to the first modification of the present invention. In FIG. 8, the oblique cut type reflection suppressing portion 4 </ b> A has a shape obtained by obliquely cutting a cylinder, and includes an obliquely cut upper bottom surface 4 d, a circumferential surface 4 c, and a bottom surface 4 e. Here, the vertex angle between the upper bottom surface 4d and the circumferential surface 4c is preferably set to 45 ° ± 10 °. Since the cylindrical wall surface of the reflection suppressing portion 4A is parallel to the traveling axis of the sound wave, and the upper bottom surface of the oblique cut is a cover of the oblique cut portion, the material of the circumferential surface 4c is, for example, a multilayer wound paper having a thickness of about 10 mm. It is preferable to use a tube. The material of the upper bottom surface 4d is preferably soft wood having a thickness of 1 to 2 mm, such as balsa wood or soft resin.

  FIG. 9 is a perspective view showing a structure of a pyramidal reflection suppressing portion 4B according to the second modification of the present invention. In FIG. 9, the pyramid-type reflection suppressing portion 4B has a pyramid shape with a square bottom surface, and the apex angle is preferably 60 ° to 100 ° for the same reason as the conical shape. The square diagonal length of the bottom surface is approximated to the inner diameter of the cylindrical housing 2 as much as possible. Further, the wall surface of the reflection suppressing portion 4B is preferably made of soft wood having a thickness of 1 to 2 mm, such as balsa wood. The inside is filled in the same manner as the conical reflection suppressing portion 4.

  FIG. 10 is a cross-sectional view corresponding to FIG. 4 of a tandem drive type speaker device according to a third modification of the present invention. Compared with the first embodiment shown in FIG. 4, the third modified example further includes a cylindrical thin tube 25 that is thinner than the cylindrical thin tube 20 in the internal space 20 a of each cylindrical thin tube 20. It is characterized in that 7 cylindrical capillaries 25 are filled and accommodated. Thereby, the maintenance function of the plane wave in each cylindrical tubule can be extended to a high region, and the sound absorption effect in the cylindrical housing 2 can be further enhanced. In the third modified example, seven cylindrical capillaries 25 are filled and accommodated per one cylindrical capillaries 20, but the present invention is not limited to this, and preferably four cylindrical capillaries 25 or A plurality of cylindrical thin tubes 25 may be accommodated.

  FIG. 11 is a cross-sectional view corresponding to FIG. 4 of a tandem drive speaker device according to a fourth modification of the present invention. The fourth modification is characterized in that a regular hexagonal tubular capillary 26 is filled and accommodated in place of the cylindrical capillary 20 according to the first embodiment. In the case of the regular hexagonal tubular tubule 26, the cross-section has a so-called honeycomb shape, and no space is created between the regular hexagonal tubular tubules 26. Therefore, a large number of regular hexagonal tubular tubules 26 are accommodated and plane waves are maintained. Sound quality improvement can be made remarkable.

  FIG. 12 is a cross-sectional view corresponding to FIG. 4 of a tandem drive speaker device according to a fifth modification of the present invention. This fifth modification is characterized in that an isosceles triangular cylindrical capillary 27 is filled and accommodated instead of the cylindrical capillary 20 according to the first embodiment. In the case of the isosceles triangular cylindrical tubule 27, no space is created between the respective isosceles triangular cylindrical tubules 27. Therefore, a large number of isosceles triangular cylindrical tubules 27 are accommodated to significantly improve sound quality by maintaining plane waves. Can be.

  FIG. 13 is a cross-sectional view corresponding to FIG. 4 of a tandem drive type speaker device according to a sixth modification of the present invention. In this sixth modification, instead of the cylindrical thin tube 20 according to the first embodiment, the thin tube located in the central portion of the cylindrical housing 2 is the cylindrical thin tube 20, but the central thin tube 20 and It is characterized in that an elliptic cylindrical tube 28 is filled and accommodated between the cylindrical housing 2. Since each elliptic cylindrical tube 28 has an inner diameter that is not constant like a circle, standing waves are not easily generated in the narrow tube, and the number of peripheral elliptic cylindrical tubes 28 can be increased, so that sound quality can be improved. .

  In the above embodiments and modifications, the cylindrical housing 2 is used. However, the present invention is not limited to this, and a housing having a polygonal or elliptical cylindrical shape other than the cylindrical shape is used. Also good.

  In the above embodiments and modifications, the cylindrical capillaries 20, 30, and 40 are used. However, the present invention is not limited to this, and a cylindrical shape such as a polygonal or elliptical shape other than the cylindrical shape or an elliptical cylindrical shape. You may use the thin tube which has.

In the present embodiment, the processing of the sound wave processing unit 102 will be described. Among the functions necessary for the sound wave processing unit 102, an indispensable technique that is indispensable for realizing a tandem drive type speaker device uses the minimum resonance frequency f _0c of the speaker unit 51 mounted in the cylindrical housing 2. it is set to a value close as possible to the minimum resonance frequency f ₀ of the free space of the speaker units. The following is a theoretical explanation of the technology that achieves this.

  The internal volume V of the cylindrical housing 2 is expressed by the following equation. In this specification, the number number of the black brackets in which the mathematical formula is imaged and the formula number of the square brackets in which the mathematical formula is input are used in combination. The formula number is assigned to the last part of the formula using the format of “formula (1)” as the formula number.

[Equation 1]
V = (350 × a ⁴ ) / [m ₀ (f _0c ² −f ₀ ² )] (liter) (1)

Here, a is the effective radius (cm) of the diaphragm of the speaker unit, and m ₀ is the effective weight of the diaphragm, which is expressed by the following equation.

[Equation 2]
m ₀ = m _c + m _a (2)

Here, m _c is the weight when the diaphragm is stationary, and m _a is the weight of air that moves with the diaphragm during operation. The weight of air is 1.2 grams / liter.

In this case, when the lowest resonance frequency f _0c of the speaker unit 51 attached to the speaker unit coupling portion 101 of the cylindrical housing 2 is derived from the above equation (1), the following equation is obtained.

In the cylindrical housing type tandem drive speaker device experimentally manufactured by the present inventor, by using the technique mainly increasing the weight m _a which is the technique according to the present invention, how close the minimum resonance frequency f _{0c is} to the minimum resonance frequency f ₀ or could be, by weight from the measured value of the minimum resonance frequency f _0c and f ₀ in the reverse m _a, that is, the weight of the air (strictly that moves with the diaphragm, the air spring force opposing the movement of the weight m _a how long were able to increase the pointing minus value), and their values are given in the following.

The following shows various numerical values of a prototype device according to the present inventor, seeking the value of the weight m _a.

(1) V = 4.3 liters (effective volume of speaker unit coupling portion 101).
(2) a = 2.8 cm (effective radius of 8 cm speaker unit 1, 51)
(3) m _c = 1.4 gr (weight of the diaphragm of the speaker unit 1, 51).
(4) f ₀ = 95 Hz (minimum resonance frequency in free space (see FIG. 14)).
(5) f _0c = 100 Hz (minimum resonance frequency of actually measured data of the prototype device (see FIG. 15)).

Here, FIG. 14 is a frequency characteristic diagram showing the lowest resonance frequency f ₀ in free space in one 8 cm speaker unit. FIG. 15 is a tandem drive type speaker device of FIG. 1 (however, the reflection suppressing portion is not disposed and only the first and second sound absorbing layers 5 and 6 are mounted), and two 8 cm speaker units are mounted. It is a frequency characteristic figure which shows the lowest resonance frequency _f0c at the time.

From the above formula (3), the weight m _a is expressed by the following formula.

[Equation 3]
m _a = [350 × a ⁴ / V (f _0c ² −f ₀ ² ) −m _c (4)

  Substituting the above values in the above equation (4) gives the following equation.

[Equation 4]
m _a = 3.73 gr (5)

Therefore, the weight of air with an effective volume V (4.3 liters) is [Equation 5].
4.3 × 1.2 = 5.16gr (6)
Therefore, the effective participation rate (effective contribution rate) A of air in the speaker unit coupling portion 101 is expressed by the following equation.

[Equation 6]
A = (3.73 / 5.16) × 100%
= 72.3% (7)

As is clear from the above equation (7), it can be seen that the weight of the air moving together with the diaphragm of the speaker unit is greatly increased, and thus, how close the lowest resonance frequency f _{0c is} to the lowest resonance frequency f ₀ . The amount that could be evaluated was a relative amount.

  As described above in detail, according to the tandem drive type speaker device and the structure thereof according to the present invention, the sound wave radiated into the cylindrical casing by the reflection suppressing portion is generated at the other end of the cylindrical casing. While substantially suppressing reflection, the sound waves propagating in the speaker unit coupling portion and the sound wave processing portion are caused to enter the inside of the cylindrical housing by the first tubular tubule and the plurality of second tubular tubules. The emitted sound wave can be maintained as a substantially plane wave. As a result, the lowest resonance frequency in the tandem drive type speaker device can be drastically reduced to improve the low frequency characteristics, and the increase in the sound pressure of the overall frequency characteristics in the tandem drive can be reproduced with the original sound faithfully reproduced. realizable.

1 is a partially broken perspective view showing a structure of a tandem drive type speaker device according to a first embodiment of the present invention. It is a longitudinal cross-sectional view about the A-A 'line | wire of FIG. FIG. 3 is a cross-sectional view taken along line B-B ′ of FIG. 2. FIG. 3 is a transverse sectional view taken along line C-C ′ of FIG. 2. It is a partially broken perspective view which shows the structure of the tandem drive type speaker apparatus which concerns on the 2nd Embodiment of this invention. FIG. 6 is a top view of the tandem drive type speaker device of FIG. 5. It is a longitudinal cross-sectional view of the upper part of the tandem drive type | mold speaker apparatus of FIG. It is a perspective view which shows the structure of 4 A of diagonal cut type | mold reflection suppression parts which concern on the 1st modification of this invention. It is a perspective view which shows the structure of the pyramid type | mold reflection suppression part 4B which concerns on the 2nd modification of this invention. It is a cross-sectional view corresponding to FIG. 4 of the tandem drive type speaker device according to a third modification of the present invention. It is a cross-sectional view corresponding to FIG. 4 of the tandem drive type speaker apparatus which concerns on the 4th modification of this invention. It is a cross-sectional view corresponding to FIG. 4 of the tandem drive type speaker device according to the fifth modification of the present invention. It is a cross-sectional view corresponding to FIG. 4 of the tandem drive type speaker device according to a sixth modification of the present invention. It is a frequency characteristic diagram showing the lowest resonance frequency f ₀ of the free space in one 8cm speaker units. In the tandem drive type speaker device of FIG. 1 (however, the reflection suppressing portion is not disposed and only the first and second sound absorbing layers 5 and 6 are provided), the minimum when two 8 cm speaker units are mounted. It is a frequency characteristic figure which shows resonance frequency _f0c .

Explanation of symbols

1, 51 ... speaker unit,
1a, 51a ... diaphragm,
1b, 51b ... magnet,
2 ... Cylindrical housing,
3 ... Case base part,
4, 4A, 4B ... reflection suppression part,
5, 6 ... sound absorption layer,
13, 14 ... Sound absorbing material,
20, 25, 30, 40 ... cylindrical capillaries,
20a, 30a ... internal space,
21, 22 ... space,
26 ... Regular hexagonal cylindrical tubule,
27 ... Isosceles triangular cylindrical tubule,
28 ... elliptical tubular tubule,
61 ... High-frequency range playback speaker,
101 ... Speaker unit coupling part,
102: Sonication processing unit.

Claims (5)

One speaker unit is provided with a housing having two speaker units that are spaced apart from each other by a predetermined distance and facing outward, and the two speaker units are substantially free of acoustic vibrations. In the tandem drive type speaker device that is electrically driven in substantially opposite phase so as to be in phase,
The casing is a cylindrical casing with the other end sealed,
In the speaker unit coupling portion in which the two speaker units are disposed, a first tubular tube provided so as to surround the magnets of the two speaker units;
In the sound wave processing section between the speaker unit coupling section and the other end of the cylindrical housing, the longitudinal direction of each tubular tubule is substantially parallel to the longitudinal direction of the cylindrical casing in the cylindrical casing. A plurality of second tubular tubules for maintaining a sound wave substantially contained in a plane wave when housed and exciting the two speaker units;
A reflection suppressing portion that is provided at the other end of the cylindrical housing and substantially suppresses the sound wave radiated inside the cylindrical housing from being reflected at the other end of the cylindrical housing;
In the speaker unit coupling portion, the tube is accommodated in the tubular housing so that the longitudinal direction of each tubular tubule is substantially parallel to the longitudinal direction of the tubular housing, and the two speaker units are excited. A tandem drive type speaker device comprising: a plurality of third tubular tubes for maintaining a sound wave radiated inside the housing as a substantially plane wave.   The reflection suppression unit has a conical shape with a vertex facing the two speaker units, a pyramid shape with a vertex facing the two speaker units, or an oblique cut shape. The tandem drive type speaker device according to claim 1.   The tandem-driven speaker device according to claim 1 or 2, wherein the reflection suppression unit includes a sound wave absorbing layer that absorbs sound waves on a surface thereof.   The cylindrical housing type speaker device according to any one of claims 1 to 3, further comprising a sound-absorbing material provided between each of the tubular thin tubes and the cylindrical housing. . 5. The high-frequency range reproduction speaker provided on the front surface of one of the two speaker units that is arranged outwardly, further comprising: a high-frequency range reproduction speaker. The cylindrical housing type speaker device according to one.

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