JP3268028B2 - Speaker system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speaker system having an acoustic tube for guiding sound waves in front of a speaker.

[0002]

2. Description of the Related Art Conventionally, a method in which a horn or an acoustic tube is provided in front of a speaker diaphragm to guide sound waves generated from the speaker diaphragm to an opening portion is compared with a case where a horn or an acoustic tube is not used. It is widely used because of its advantages such as high pressure and the ability to transmit sound in a specific direction.

As shown in FIG. 7, a conventional speaker system 1 includes a speaker 2 and a horn 3 disposed on the front of the speaker 2. A speaker diaphragm 4 is provided on the front surface of the speaker 2, and an opening as a horn entrance 5 is provided on the front surface of the speaker diaphragm 4, while a horn outlet 6 is provided on the opposite side of the speaker. Opening is provided.

The horn 3 is formed so that the cross-sectional area of the opening gradually increases from the horn inlet 5 to the horn outlet 6. The frequency characteristics of the loudspeaker system 1 formed as described above can be obtained with good frequency characteristics if the length of the horn 3 is sufficiently longer than the wavelength of the band to be reproduced.

However, in the above configuration, when the speaker system 1 is incorporated in a television set, for example, it is not possible to obtain a sufficient horn length with respect to the wavelength. And a reflected wave is generated, resulting in a frequency characteristic having many peak dips as shown in FIG.

Accordingly, Japanese Patent Laid-Open Publication No. 63-313998 proposes, for example, a speaker system 1 'for obtaining a good frequency characteristic with a short horn length and a small peak dip as shown in FIG. .

In the speaker system 1 ', an acoustic tube 7 is provided on the front surface of the speaker diaphragm 4, and the acoustic tube 7 is provided.
The horn 3 'is formed by a sound absorbing material 8 and disposed inside. The horn 3 'is formed such that the thickness of the sound absorbing material 8 is thinner at the horn outlet 6 side and thicker at the horn inlet 5 side.

In FIGS. 7 and 9, the back cavity of the speaker 2 is omitted.

[0009]

However, in the loudspeaker system as described above, in order to manufacture a large number of horns of the same shape using the sound absorbing material, the amount and density of the sound absorbing material forming the horn must be the same. It was difficult to obtain the characteristic variation.

[0010] Further, in order to keep these characteristics constant, the work process becomes complicated and causes a high cost.

Further, since the horn is formed by filling the sound absorbing material on both sides of the acoustic tube, the speaker system has been increased in size.

The present invention eliminates the above problems.
It is an object of the present invention to provide a small-sized speaker system with stable frequency characteristics at low cost without increasing the length of an acoustic tube.

[0013]

According to the present invention, there is provided a speaker system having an acoustic tube for guiding sound waves to the front surface of a diaphragm of a speaker. A baffle plate having an opening with a small opening area, a first acoustic tube chamber disposed in front of the baffle plate and having a gradually decreasing opening area from the entrance of the acoustic tube toward the exit of the acoustic tube; An acoustic tube second chamber which is located in front of the first tube and has a gradually increasing opening area from a connection with the first acoustic tube toward an outlet of the acoustic tube, and a side surface of the first acoustic tube And a sound absorbing material filled in the third acoustic tube, the third acoustic tube having a connection portion with the first acoustic tube and communicating with a gap formed by an adjusting rib.

[0014]

The loudspeaker system having the above-described structure outputs sound waves generated by the loudspeaker diaphragm from the outlet of the sound tube through the opening, the entrance of the sound tube, the first room of the sound tube, and the second room of the sound tube. At this time, sound waves are transmitted from the baffle plate having an opening formed to be smaller than the area of the opening of the speaker diaphragm to the first acoustic tube chamber whose opening area is gradually reduced from the entrance of the acoustic tube toward the exit of the acoustic tube. In addition, the gap between the first and third acoustic tube chambers is adjusted to guide sound waves to the third acoustic tube room, thereby preventing the radiation impedance from being disturbed.

The sound absorbing material filled in the third chamber of the acoustic tube reduces disturbance of the acoustic impedance in the first and second chambers of the acoustic tube and generates a standing wave by absorbing the reflected wave. And suppress the peak dip to obtain a good frequency characteristic.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 relate to one embodiment of the present invention, and FIG. 1A is a cross-sectional view of the speaker system of FIG.
(B) is a front view of the speaker system of (a), FIG. 2 is a cross-sectional view of the speaker system of FIG. 3, taken along line AA, FIG. 3 is a perspective view of the speaker system, and FIG. FIG. 5 is a characteristic diagram showing the frequency characteristics of the speaker.

The configuration of the speaker system will be described with reference to FIGS. As shown in FIG. 4, the speaker system 10 includes a speaker 20, a baffle plate 30 disposed on the front surface of the speaker 20, and an acoustic tube first chamber described later disposed on the front surface of the baffle plate 30 and guiding sound waves. 41, an acoustic tube 40 including an acoustic tube second room 42 and an acoustic tube third room 43
Etc.

The baffle plate 30 has a through hole 3 through which a connecting member 60 for holding the baffle plate 30 is inserted.
1 and an opening 32 for guiding the sound wave of the speaker 20 to the acoustic tube 40 are provided. The opening 32 is smaller than the area of the diaphragm 21 of the speaker 20, and is formed, for example, in a square shape. An acoustic tube entrance 44 for guiding sound waves to the first acoustic tube chamber 41 is provided on the front surface of the baffle plate 30.

As shown in FIG. 1 to FIG.
Reference numeral 0 denotes a first acoustic tube chamber 41 in which the sectional area of the acoustic tube is gradually reduced from the entrance 44 of the acoustic tube toward the exit 45 of the acoustic tube.
A second acoustic tube chamber 42 disposed in front of the first acoustic tube chamber 41 and gradually increasing in cross section of the acoustic tube toward the acoustic tube outlet 45; a sudden change in acoustic impedance and a reflected wave; An adjusting rib 46 for forming a space for filling a sound absorbing material 50 for suppressing the standing wave is provided by a gap 47 extending to near the baffle plate.
Acoustic tube third room 4 that becomes a Helmholtz resonator by communicating with 1
3 are formed.

The space of the third chamber 43 of the acoustic tube is filled with a sound absorbing material 50 to reduce standing waves, and the gap 4 between the adjusting rib 46 and the baffle plate 30 is reduced.
By appropriately setting 7, the acoustic load can be adjusted to reduce the disturbance of the acoustic impedance.

The operation of the speaker system 10 configured as described above will be described. Sound waves radiated from the diaphragm 21 of the speaker 20 are transmitted through the opening 32 of the baffle plate 30, the sound tube entrance 44, and the first sound tube chamber 4.
After passing through the first and second sound tube chambers 42, the light is guided to the sound tube outlet 45 and emitted.

At this time, the opening 3 of the baffle plate 30
Since the area 2 is formed smaller than the opening area of the speaker diaphragm 21, an acoustic space acting as a compliance can be reduced by applying an acoustic load on the front of the speaker.

The first chamber 41 of the acoustic tube is formed so that the cross-sectional area decreases from the entrance 44 of the acoustic tube toward the exit 45 of the acoustic tube, so that the air elasticity of the air in the acoustic tube 40 is reduced. As a result, the sound pressure rises and the disturbance of the radiation impedance is suppressed, while the acoustic tube first chamber 41
A third acoustic tube chamber 43 and a third acoustic tube room 4
The acoustic impedance disturbance which rapidly changes due to the sound absorbing material 50 filled in 3 and the standing wave due to the reflected wave generated inside the acoustic tube 40 are suppressed.

As described above, the speaker system 1 of the present invention
0 indicates that a frequency characteristic with a small peak dip can be obtained at the sound tube outlet 45 as shown in FIG.

Further, the speaker system 10 can be miniaturized by providing the sound absorbing material 50 only on one side surface in the speaker system 10.

Further, the sound absorbing material 50 can be easily filled into the sound tube 40 in the speaker system 10, and the sound tube 30 has a shape suitable for being manufactured as a molded product, so that the sound tube 30 is integrally formed. As a result, productivity can be improved and products can be supplied stably.

In order to increase the strength of the first acoustic tube chamber 41 and the second acoustic tube room 42, a reinforcing plate 48 is provided from the entrance of the acoustic tube to the exit of the acoustic tube.

FIG. 6 is a side view of a speaker system 10 'according to a modification of the present embodiment. As shown in the figure, the speaker system 10 'of the present embodiment has the acoustic tube second chamber 42 arranged to be inclined with respect to the central axis. Other configurations are the same as those in the above embodiment.

As described above, the sound tube outlet 45 can be set at a desired position by inclining the sound tube second chamber 42 at a desired angle θ with respect to the central axis. Other functions and effects are the same as those of the above-described embodiment.

In the above embodiment, the acoustic tube 40
Has a square cross section, but the cross section of the acoustic tube may be elliptical or the like. Further, in the drawings of the above-described embodiment, the back cavity of the speaker 20 is omitted.

[0031]

As described above, according to the present invention, a small-sized speaker system having stable frequency characteristics can be provided at low cost without increasing the length of the acoustic tube.

[Brief description of the drawings]

FIGS. 1 to 5 relate to an embodiment of the present invention. FIG. 1 (a) is a sectional view taken along line BB of the speaker system of FIG. 3, and FIG. 1 (b) is a front view of the speaker system of FIG.

FIG. 2 is a cross-sectional view of the speaker system of FIG. 3 taken along line AA.

FIG. 3 is a perspective view of a speaker system.

FIG. 4 is a perspective view showing an assembly configuration of the speaker system.

FIG. 5 is a characteristic diagram showing frequency characteristics of a speaker.

FIG. 6 is a side view of a speaker system according to a modification of the present invention.

7 to 9 relate to a conventional example of the present invention, and FIG. 7 is a side sectional view schematically showing a speaker system.

FIG. 8 is a characteristic diagram showing frequency characteristics of the speaker system of FIG. 7;

FIG. 9 is a schematic configuration diagram showing an example of a conventional speaker system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Speaker system 20 ... Speaker 30 ... Baffle board 41 ... Sound tube 1st room 42 ... Sound tube 2nd room 43 ... Sound tube 3rd room 44 ... Sound tube entrance 45 ... Sound tube outlet 46 ... Adjustment rib 47 ... Gap 50 ... Sound absorbing material

Claims (1)

(57) [Claims] 1. A speaker system having an acoustic tube for guiding sound waves to the front of a diaphragm of a speaker, wherein the baffle has an opening disposed on the front of the speaker diaphragm and having an opening area smaller than that of the speaker diaphragm. A sound tube first chamber disposed in front of the baffle plate and having an opening area gradually reduced from the sound tube entrance toward the sound tube exit direction; and a sound tube first room disposed in front of the sound tube first room; An acoustic tube second chamber having an opening area gradually increasing from a connection portion with the acoustic tube first chamber toward the acoustic tube outlet; and the acoustic tube first chamber located on a side surface of the acoustic tube first chamber. And a sound absorbing material filled in the third tube of the acoustic tube, wherein the third tube communicates with a gap formed by a rib for adjustment.