JP3171542B2 - Loudspeaker device and television receiver using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a loudspeaker device constructed by connecting an acoustic tube to a loudspeaker and a television receiver equipped with the loudspeaker device.

[0002]

2. Description of the Related Art In a television receiver, FIG.
As shown in (1), a cathode ray tube (11) is accommodated in a cabinet (1), and a pair of left and right speakers (12) is arranged by utilizing a dead space generated between the cabinet (1) and the cathode ray tube (11). Sound waves radiated from each speaker (12) are transmitted to the cabinet (1) by an acoustic tube (13) connected to the speaker (12).
Leading to the front has been done.

With the recent increase in the size of television receivers, the loudspeaker (12) has also become larger in diameter, and such a large-diameter loudspeaker (12) is connected to a cathode ray tube (1) as shown in FIG.
When the cathode ray tube (11) is disposed on both sides of the cabinet (1), it is necessary to take measures such as providing a bulge on the side surface of the cabinet (1) because the cathode ray tube (11) does not fit in the dead space in the cabinet (1). This causes a problem that the lateral width of the cabinet (1) increases.

[0004] Therefore, as shown in FIG.
Can be conceived to be arranged obliquely laterally with respect to the front of the cabinet (1) and connected to the acoustic tube (14). As a result, the large-diameter speaker (12) can be compactly arranged in the dead space in the cabinet (1).

[0005]

However, FIG.
In the speaker device shown in (1), the sound wave radiated from the speaker (12) is refracted at a large angle close to 90 degrees and introduced into the acoustic tube (14). is there.

In each of the speaker devices shown in FIGS. 22 and 23, sound waves radiated from the speaker (12) are guided inside the acoustic tube (13) and then forward from the opening end of the acoustic tube. When radiated, part of the sound wave is reflected due to a sudden change in the acoustic impedance at the opening end of the acoustic tube,
When this returns to the speaker (12), a standing wave is generated. For example, when 3/4 of the wavelength of the standing wave is equal to the length of the acoustic tube (3/4 wavelength standing wave), resonance occurs,
A sharp peak occurs around 700 Hz to 1 kHz in the sound pressure frequency characteristic. As a result, the acoustic characteristics particularly in the middle range are deteriorated.

In order to eliminate the disturbance of the sound pressure frequency characteristics due to the standing wave, a speaker device has been proposed in which a sound absorbing material is arranged inside the acoustic tube so as to surround the sound wave radiating portion of the speaker to absorb the standing wave. (Japanese Patent Laid-Open No. 5-168082 [H04R1 / 34]), however, in this device, sound waves reflected on the front of the speaker do not hit the sound absorbing material, and can effectively absorb the standing wave. Can not.

An object of the present invention is to provide a loudspeaker device in which a waveguide direction of an acoustic tube is inclined with respect to a sound wave radiation direction of a loudspeaker. It is to realize good acoustic characteristics.

[0009]

A speaker device according to the present invention is constructed by connecting an acoustic tube (4) having one end opened and the other end closed to a sound emitting portion of a speaker (3). Here, the loudspeaker (3) is attached to the side surface of the acoustic tube (4). The mounting position is set at an intermediate portion between the closed end and the open end of the acoustic tube (4).

More specifically, the speaker (3) is an acoustic tube (4)
Is mounted at a position closer to the open end side from the closed end by approximately 略 of the total length of the.

In a specific configuration, the inside of the acoustic tube (4) is closer to the closed end side than the mounting position of the speaker (3).
The sound absorbing material (5) is filled.

Specifically, the waveguide of the acoustic tube (4) is
The cross-sectional area is substantially constant or increases from the mounting position of the speaker (3) toward the opening end. Furthermore, the cross-sectional area of the waveguide of the acoustic tube (4) decreases from the mounting position of the speaker (3) toward the closed end.

A speaker (3) is provided on the inner surface of the acoustic tube (4).
A truncated cone-shaped protruding portion (6) protruding toward the speaker (3) is formed at a portion facing the acoustic wave emitting portion.

In a more specific configuration, a reflector (not shown) is provided inside the acoustic tube (4) at a predetermined position closer to the closed end than the mounting position of the speaker (3) to close a part of the waveguide at the predetermined position. 7) is installed.

Further, the terminals (32) for energizing the speaker (3) are placed on the frame (30) at a position eccentric from the center of the speaker (3) toward the opening end of the acoustic tube (4). Supported from the terminals (32) and (32) toward the diaphragm (31).
3) (33) is growing.

In the television receiver according to the present invention, a pair of left and right speaker devices (2) and (2) are arranged inside a cabinet (1) with a cathode ray tube (11) interposed therebetween. The sound tube () extends from the closed end on the back side of the cabinet (1) to the open end on the front side of the cabinet (1) on the sound wave radiating portion of the speaker (3) arranged laterally behind the cabinet (1). 4) are connected. Speaker
(3) is attached to the side of the acoustic tube (4), and the speaker
The direction in which the acoustic tube (4) is guided intersects with the direction in which the acoustic wave is emitted in (3), and the mounting position of the speaker (3) is
It is set in the middle part between the closed end and the open end of (4).

[0017]

[Action] The standing wave generated inside the acoustic tube (4) is an acoustic tube.
The closed end of (4) is a node and the open end is an antinode, and one or more antinodes are generated between the closed end and the open end to resonate. Therefore, in the conventional device in which the speaker is attached to the closed end of the acoustic tube, the attachment position is opposed to the position of the node of the standing wave, and the driving force of the speaker efficiently contributes to the generation of the standing wave. And a large standing wave was generated. On the other hand, in the speaker device of the present invention, the speaker (3) is attached to an intermediate portion between the closed end and the open end of the acoustic tube (4), and the attachment position is at one antinode of the standing wave. By facing the position,
The driving efficiency of the speaker with respect to the standing wave is reduced. As a result, the standing wave is suppressed, and especially the acoustic characteristics in the middle range are improved.

The position of the antinode of the standing wave is, for example, a position which is closer to the opening end side from the closed end by about 1/3 of the entire length of the acoustic tube (4). In the specific configuration where the speaker (3) is mounted, the mounting position of the speaker (3) is three.
/ 4 wavelength standing wave antinode position, thereby 3 /
The resonance of the four-wavelength standing wave is effectively suppressed.

A sound absorbing material is provided on the closed end side inside the acoustic tube (4).
In a specific configuration filled with (5), the totally reflected wave returning from the open end of the acoustic tube (4) hits the sound absorbing material (5),
It will be absorbed by (5).

The waveguide of the acoustic tube (4) has a substantially constant or enlarged cross-sectional area from the mounting position of the speaker (3) toward the open end, and the waveguide from the mounting position of the speaker (3) toward the closed end. In the configuration where the cross-sectional area is reduced, the cross-sectional size of the acoustic tube opening end where the reflected wave occurs and the cross-sectional size of the acoustic tube closed end where the reflected wave finally reaches are different from each other. The asymmetry results in a weakened reflected wave at the closed end.

Also, in the configuration in which a truncated cone-shaped raised portion (6) similar to a speaker diaphragm is formed in a portion of the speaker (3) facing the sound wave emitting portion, the speaker (3) generated by the concave shape of the speaker diaphragm. 3) Abrupt changes in the cross-sectional area of the waveguide at the exit are canceled out by the ridges (6), and as a result, the change in acoustic impedance at the connection between the speaker (3) and the acoustic tube (4) is reduced. .

Further, in the configuration in which the reflector (7) is installed at a predetermined position closer to the closed end than the mounting position of the speaker (3), an effect of improving the high frequency range of the acoustic characteristics can be obtained, and the high frequency range from the middle frequency range can be obtained. A well-balanced acoustic characteristic is realized over a range.

Furthermore, the terminals (32) and (3) of the speaker (3)
In the configuration in which 2) is arranged at a position eccentric to the opening end side of the sound tube (4), the imbalance of the sound pressure resistance of the speaker (3) with respect to the diaphragm (31), that is, the opening end side of the sound tube (4). The unbalance of the sound pressure resistance and the terminal
The weight of the tinsel wire (33) and the lead wire extending from (32) to the diaphragm (31) and the equivalent mass increase due to the weight of the tinsel wire (33) and the solder for fixing the lead wire cancel each other. by this,
The diaphragm (31) performs only one-dimensional vibration along the sound wave radiation direction. As a result, good sound quality without distortion is obtained.

In the television receiver according to the present invention, a pair of left and right speaker devices (2) and (2) are arranged inside a cabinet (1) with a cathode ray tube (11) interposed therebetween. 3) is arranged horizontally in the back of the cabinet (1), so that even if the speaker (3) has a large diameter, the width of the cabinet (1) is not increased.
The compact arrangement of the speaker (3) is possible by effectively utilizing the dead space. Further, in the speaker device (2), since the mounting position of the speaker (3) is set at an intermediate portion between the closed end and the open end of the acoustic tube (4), standing waves are effectively suppressed.

[0025]

According to the loudspeaker apparatus and the television receiver using the same according to the present invention, the problem caused by inclining the waveguide direction of the acoustic tube with respect to the sound wave emission direction of the loudspeaker, that is, the problem caused by the medium Generation of a peak dip centered on the band is effectively suppressed, and good acoustic characteristics can be obtained in a wide range from a low band to a high band.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a speaker device according to the present invention.
This shows an embodiment in which (2) is mounted on a television receiver, and a pair of left and right speaker devices (2) and (2) are arranged inside a cabinet (1) on both sides of a cathode ray tube (11). Have been.

The speaker device (2) uses the dead space inside the cabinet (1) to arrange the speaker (3) horizontally in the back of the cabinet (1),
In (4), the closed end is disposed toward the back of the cabinet (1), and the open end is disposed toward the front of the cabinet (1).
The front of the speaker (3) is attached to the side of (4).

The speaker (3) is a general cone type dynamic speaker as shown in FIG. 2, and a diaphragm (31) made of cone paper is supported on a frame (30) via a damper. By energizing the pair of terminals (32), (32), the diaphragm (31) is driven. As shown in FIG. 3, the speaker (3) is mounted at a position closer to the opening end side from the closed end by １ ／ of the entire length of the acoustic tube (4).

The acoustic tube (4) is constructed by combining a first panel (41) and a second panel (42), whereby a speaker (3) is provided between the two panels (41) and (42). Also, the front waveguide (43) is formed on the opening end side, and the rear waveguide (44) is formed on the closing end side of the speaker (3).

As shown in FIG. 4, the front waveguide (43) of the acoustic tube (4) expands toward the open end in accordance with a constant function, and at the same time, the thickness of the front waveguide (43) is close to the closed end due to the reciprocal relationship of the function. And its cross-sectional area is constant from the mounting position of the speaker (3) to the opening end. As a result, on the front surface of the cabinet (1), the opening end of the acoustic tube (4) is opened in the shape of a vertically elongated rectangle, and the expansion of the horizontal width of the cabinet (1) is minimized. In contrast, sound tubes
The cross section of the rear waveguide (44) of (4) gradually decreases toward the closed end. The back portion of the rear waveguide (44) is filled with a sound absorbing material (5).

In the first panel (41), a circular window (45) for introducing a sound wave from the speaker (3) into the acoustic tube (4) is opened at a position where the speaker (3) is mounted. I have. Also, the second
The panel (42) has a truncated conical ridge (6) corresponding to the shape of the diaphragm (31) of the speaker (3) at a position facing the circular window (45) of the first panel (41). , Protruding toward the speaker (3).

The speaker device shown in FIGS.
At the entrance of the rear waveguide (44) of the acoustic tube (4), a pair of reflectors
(7) (7) is installed at an interval from each other. The rear of these reflectors (7) (7) is similarly filled with a sound absorbing material (5).

Further, in the speaker device shown in FIGS. 7 and 8, the terminals (32) and (32) of the speaker (3) are
The terminal (32) (3) is supported on the frame (30) at a position eccentric from the center of (3) to the opening end of the acoustic tube (4).
Kinshi wires (33) and (33) extend from 2) toward the diaphragm (31).

The effect exhibited by the above-described speaker device was confirmed experimentally by manufacturing an experimental speaker device shown in FIGS. 11 to 21 show the results of the experiment. In the experimental speaker device, as shown in FIGS. 9 and 10, a speaker (3) is attached to the side of an experimental acoustic tube (8) having a constant cross-sectional area over the entire length of the waveguide.
It has basically the same structure as the speaker device of the present invention. Then, a microphone (9) was installed so as to face the opening end of the experimental sound tube (8), and the sound pressure frequency characteristics of the speaker device were measured. The total length of the experimental sound tube (8) is 350 mm, and the cross-sectional shape is a rectangle of 105 mm × 50 mm. The microphone (9) was set at a distance of 10 mm from the opening end of the acoustic tube (4).

FIG. 11 shows a standing wave generated in an acoustic tube having a constant sectional area. Here, assuming that the length of the acoustic tube is L, the frequency F at which the standing wave is generated is expressed by the following equation (1).

[0036]

F = (c / 4L) × (2n + 1) where c is a sound speed, and n is an integer (0, 1, 2,...).

When L = 0.35 m and c = 340 m / s,
The frequencies F1, F2, and F3 that cause the 1/4 wavelength standing wave, the 3/4 wavelength standing wave, and the 5/4 wavelength standing wave are respectively as follows. F1 = 243 Hz F2 = 729 Hz F3 = 1214 Hz

When the closed end of the sound tube is driven by the speaker having the frequency characteristics indicated by the broken line in FIG. 12, the frequency characteristics of the sound waves emitted from the sound tube are as shown by the solid lines in the figure.
A large peak dip occurs repeatedly from the midrange to the high range, and is disturbed. The solid line frequency characteristics are calculated by computer simulation.

On the other hand, as shown in FIG. 13, in the A type in which a speaker is installed at a position 1/3 of the total length from the closed end of the acoustic tube and in the B type in which a speaker is installed at a position 1/2, respectively. From the experimental results, the frequency characteristics shown in FIGS. 15 and 14 were obtained.

That is, in the B type in which the speaker is installed at the half position, as shown by the solid line in FIG. 14, a part of the band (around 1 kHz) is slightly smaller than when the closed end is driven (broken line). Although there is a large dip around 300 Hz, the sound pressure decreases around 1500 Hz. On the other hand, in the A type in which the speaker is installed at the 1/3 position, as shown by the solid line in FIG. 15, the peak dip in the middle range to the high range is sufficiently suppressed, the dip around 300 Hz is eliminated, and the 1000 Hz ~ 1800H
The sound pressure of z is sufficiently high, and good sound pressure frequency characteristics are obtained.

This is because the 1/3 position is a 3/4 wavelength standing wave.
This is an effect obtained from the fact that the position corresponds to the antinode position (generated at a frequency of 729 Hz in the present experimental example). The driving efficiency of the standing wave is reduced by driving the antinode position. It is considered that generation of waves is suppressed. Also in the experimental results of FIG. 15, the peak in the middle band around 729 Hz is significantly suppressed, confirming the effect of the speaker device of the present invention.

The D-type experimental speaker device shown in FIG. 16 has a sound tube filled with a sound absorbing material at the back thereof.
FIG. 17 shows the measurement results of the frequency characteristics. As shown by the solid line in FIG. 17, the peak dip from the middle range to the high range is effectively suppressed. This is presumably because the sound wave reflected and returned at the opening end of the acoustic tube hits the sound absorbing material without leaking and is absorbed, thereby suppressing the resonance of the standing wave.

The E-type speaker device shown in FIG. 18 has a protuberance similar in shape to the diaphragm formed opposite the speaker, and the frequency characteristic measurement results are shown in FIG.
Shown in As shown by the solid line in FIG. 19, the frequency is 800 Hz to 2500 Hz higher than the case of the D type speaker device (broken line).
The sound pressure rises in the range. This is because in a D-type speaker device, when sound waves radiated from a speaker diaphragm are introduced into an acoustic tube, the waveguide expands rapidly due to the concave shape of the speaker diaphragm. In the loudspeaker device, the change in the waveguide cross-sectional area at the loudspeaker exit is made uniform by the formation of the bulge, thereby forming an acoustic tube without a sudden change in the cross-sectional area, and the sound waves radiated from the loudspeaker pass through the acoustic tube. It is considered that the change of the acoustic impedance when passing through is made uniform.

Further, the F type speaker device shown in FIG. 20 has a pair of reflectors arranged in front of a sound absorbing material inside an acoustic tube, and the frequency characteristic measurement results are shown in FIG.
Shown in As shown by the solid line in FIG. 21, the frequency is 6000 Hz to 7000 compared to the case of the E type speaker device (broken line).
The dip in the range of Hz has been alleviated, and it has been clarified that the sound pressure can be adjusted in a high frequency range by installing the reflector.

As described above, according to the speaker device of the present invention, the middle position of the acoustic tube (4), preferably 1 /
By mounting the speaker (3) at the position of 3, the peak dip occurring in the sound wave frequency characteristic can be effectively suppressed, and furthermore, the filling of the sound absorbing material (5) and the raised portion (6)
And the provision of the reflection plate (7) can improve the frequency characteristics from the middle range to the high range. Also, by moving the terminals (32) and (32) of the speaker (3) from the closed end side to the open end side of the acoustic tube (4), the imbalance of the resistance applied when the diaphragm (31) vibrates can be reduced. The sound quality can be improved without distortion.

Further, in the acoustic tube (4), the front waveguide (43) is formed so as to have a constant sectional area toward the front, so that the acoustic impedance from the mounting position of the speaker (3) to the opening end is constant. There is no generation of a reflected wave in the middle of the front waveguide (43), and there is no possibility of functioning as a so-called Helmholtz resonance tube.

In the television receiver according to the present invention, a pair of left and right speaker devices (2) and (2) are compactly used by effectively utilizing dead spaces generated on both sides of the cathode ray tube (11) inside the cabinet (1). Can be placed in
It is easy to cope with a large-diameter speaker (3).

The description of the above embodiments is for the purpose of illustrating the present invention, and should not be construed as limiting the invention described in the claims or reducing the scope thereof. Further, the configuration of each part of the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made within the technical scope described in the claims. For example, in the embodiment, the front waveguide (43) of the acoustic tube (4) is formed to have a constant cross-sectional area toward the opening end, but the front waveguide (43) faces the opening end of the acoustic tube. It is also possible to adopt a configuration in which the horn effect is obtained by enlarging the horn effect.

A speaker (3) is provided at an intermediate position of the acoustic tube (4).
In addition to the basic structure for mounting the loudspeaker, filling of the sound absorbing material (5), formation of the ridge (6), installation of the reflector (7), and speaker (3)
The relocation of terminals (32) and (32) is an additional configuration,
It is not always necessary to provide all of these additional components, and one or more of them can be arbitrarily selected and added.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a main part of a television receiver according to the present invention.

FIG. 2 is a perspective view of a speaker device according to the present invention.

FIG. 3 is a cross-sectional view of the speaker device.

FIG. 4 is an exploded perspective view of the speaker device.

FIG. 5 is an exploded perspective view of a speaker device including a reflector.

FIG. 6 is a perspective view showing a main part of the speaker device.

FIG. 7 is a perspective view showing a main part of the speaker device to which the terminal has been relocated.

FIG. 8 is a sectional view of the speaker device.

FIG. 9 is a perspective view of an experimental speaker device.

FIG. 10 is a sectional view of the speaker device.

FIG. 11 is a diagram showing various resonance modes.

FIG. 12 is a graph showing a sound pressure frequency characteristic when a closed end of an acoustic tube is driven.

FIG. 13 is a diagram showing two types of experimental speaker devices having different mounting positions for the speakers.

FIG. 14 is a graph showing a sound pressure frequency characteristic of a speaker device whose mounting position is か ら from a closed end.

FIG. 15 is a graph showing a sound pressure frequency characteristic of a speaker device whose mounting position is 1/3 from a closed end.

FIG. 16 is a diagram showing an experimental speaker device filled with a sound absorbing material.

FIG. 17 is a graph showing a sound pressure frequency characteristic of the speaker device.

FIG. 18 is a diagram showing an experimental speaker device in which a raised portion is formed at a position facing a speaker.

FIG. 19 is a graph showing a sound pressure frequency characteristic of the speaker device.

FIG. 20 is a diagram showing an experimental speaker device provided with a reflection plate.

FIG. 21 is a graph showing a sound pressure frequency characteristic of the speaker device.

FIG. 22 is a plan view showing an arrangement of speaker devices in a conventional television receiver.

FIG. 23 is a plan view showing another conventional example.

[Explanation of symbols]

 (1) Cabinet (2) Speaker device (3) Speaker (30) Frame (31) Diaphragm (32) Terminal (4) Acoustic tube (43) Front waveguide (44) Rear waveguide (5) Sound absorbing material (6) ) Raised part (7) Reflector

Continuation of the front page (72) Inventor Akira Nagai 1866-941 Ikutomi, Koshi-cho, Kikuchi-gun, Kumamoto Prefecture (56) References: Japanese Utility Model Sho-63-183788 (JP, U) Japanese Utility Model Hei 5-20475 ( JP, U) WO 91/19406 (WO, A1) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04R 1/02 H04R 1/28-1/34 H04N 5/64

Claims (9)

(57) [Claims] An acoustic tube, one end of which is open and the other end of which is closed, is connected to a sound wave radiating portion of a speaker, and a sound wave radiated from the speaker is transmitted to the sound tube. ), The speaker (3) is an acoustic tube.
At the side of (4), the direction of sound of the acoustic tube (4) intersects with the direction of sound wave emission of the speaker (3),
The speaker (3) is mounted at an intermediate position between the closed end and the open end of the acoustic tube (4) and opposed to the antinode of a standing wave generated inside the acoustic tube (4). apparatus. 2. The loudspeaker according to claim 1, wherein the loudspeaker is mounted at a position closer to the open end side from the closed end by a length substantially equal to one third of the entire length of the acoustic tube. apparatus. 3. The speaker according to claim 1, wherein the inside of the acoustic tube is filled with a sound absorbing material on a closed end side of the mounting position of the speaker. apparatus. 4. A waveguide according to claim 1, wherein a cross-sectional area of the waveguide of the acoustic tube is substantially constant or widened from a mounting position of the speaker toward an opening end. Speaker device. 5. The speaker device according to claim 1, wherein a cross-sectional area of the waveguide of the acoustic tube (4) decreases from a mounting position of the speaker (3) toward a closed end. . 6. A truncated cone-shaped protruding portion (6) protruding toward the speaker (3) is formed on the inner surface of the acoustic tube (4) at a portion facing the sound emitting portion of the speaker (3). The speaker device according to any one of claims 1 to 5, wherein: 7. A reflection plate (7) for closing a part of a waveguide at a predetermined position at a predetermined position closer to a closed end than a mounting position of the speaker (3) is installed inside the acoustic tube (4). The speaker device according to claim 1, wherein: 8. A terminal (32) for energizing a speaker (3).
(32) is supported on the frame (30) at a position eccentric from the center of the speaker (3) to the opening end side of the acoustic tube (4), and from the terminals (32) and (32) to the diaphragm (31). Kinshi Line (33) (33)
The speaker device according to any one of claims 1 to 7, wherein the speaker device is extended. 9. A cathode ray tube inside the cabinet (1).
(11) In a television receiver in which a pair of left and right speaker devices (2) and (2) are disposed with the speaker device (2)
A sound tube (4) extending from a closed end on the back side of the cabinet (1) to an open end on the front side of the cabinet (1) is provided on a sound emitting portion of the speaker (3) arranged laterally behind the cabinet (1). ), And the speaker (3) is an acoustic tube
At the side of (4), the direction of sound of the acoustic tube (4) intersects with the direction of sound wave emission of the speaker (3),
The mounting position of the speaker (3) is the middle of the closed end and the open end of the acoustic tube (4), and the television facing the antinode of the standing wave generated inside the acoustic tube (4). John receiver.