JPH05168081A - Speaker system provided with acoustic tube - Google Patents

Abstract

PURPOSE:To suppress the resonance phenomenon of a tube and to obtain a good sound reproduction without peak and dip in the sound pressure frequency characteristic by making the section of the acoustic tube mounted on the acoustic emission surface gradually expand able toward both opening port parts. CONSTITUTION:The system is provided with a speaker unit 1, an acoustic tube 6, an acoustic tube input part 3, an acoustic tube output part 4, and a starting point part 5 of expanding section area. In this case the part 5 corresponds to the center of the acoustic tube and its section area expands gradually toward both opening port parts of the acoustic tube input part 3 and the acoustic tube output part 4. The change amount of the section area from the starting point 5 is proportional to the square of the distance. Since the change amount of the section area of the acoustic tube 6 changes gradually toward the acoustic tube input part 3 and the acoustic tube output part 4 from the starting point part 5, the abrupt change of the acoustic impedance of the tube can be prevented. Thus, the reflection of the sound in the acoustic tube output part 4 causing the resonance of the tube can hardly be occurred.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speaker system with an acoustic tube in which a speaker unit is installed at a position different from that of a sound radiator.

[0002]

2. Description of the Related Art In recent years, a speaker system with an acoustic tube, in which a speaker unit is installed at a position different from that of a sound emitting surface, has been adopted in various audio equipment, and particularly used in a speaker system built into a TV set, a silencer in a duct, or the like. ing.

A conventional speaker system will be described below with reference to the drawings. FIG. 3 is a configuration diagram of a conventional speaker system with an acoustic tube. In FIG. 3, 1 is a speaker unit, 2 is a sound tube, 3 is a sound tube input section, and 4 is a sound tube output section.

In order to design a simple speaker system, the sound tube 2 has a cylindrical shape as shown in FIG. 3A and a sound output for a speaker unit aperture as shown in FIG. An inverted horn type in which the diameter of the portion 4 is small is mainly used. In such a configuration, the signal reproduced by the speaker unit is guided from the acoustic tube input section 3 to the acoustic tube output section 4 through the acoustic tube 2, and the signal is reproduced from there.

[0005]

However, if the acoustic tube is a cylindrical tube or has an inverted horn shape, resonance of the tube is likely to occur, and peaks and dips appear in the sound pressure frequency characteristic, impairing the acoustic characteristic. Will be done.

The present invention solves the above problems, and an object of the present invention is to provide a speaker system with an acoustic tube having a shape in which resonance of the tube is unlikely to occur.

[0007]

In order to achieve the above object, in a speaker system with an acoustic tube according to the present invention, the cross-sectional area of the acoustic tube attached to the acoustic radiation surface of the speaker unit is in both openings of the acoustic tube. It is configured to gradually expand toward.

[0008]

According to the present invention, due to the above-described structure, the resonance of the tube is unlikely to occur with respect to the cylindrical tube or the inverted horn shape, and good sound reproduction with a small peak and dip in the sound pressure frequency characteristic can be realized.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is a speaker unit, 6 is an acoustic tube, 3 is an acoustic tube input section, 4 is an acoustic tube output section, and 5 is a starting point for enlarging the sectional area. In this embodiment, the starting point portion 5 for expanding the cross-sectional area coincides with the central portion of the acoustic tube, and the cross-sectional area gradually increases from the starting point portion 5 toward the openings of the acoustic tube input section 3 and the acoustic tube output section 4. It has a shape that expands to. Also, the amount of change in the cross-sectional area from the starting point 5 is
It is proportional to the square of the distance.

In the speaker system with an acoustic tube constructed as described above, the amount of change in the cross-sectional area of the acoustic tube 6 depends on the starting point portion 5.
From the acoustic tube input section 3 to the acoustic tube output section 4, the acoustic impedance of the tube does not change abruptly, so that the acoustic tube output section 4 causing the resonance of the tube Sound reflection is less likely to occur.

FIG. 2 is a simulation result of sound pressure frequency characteristics of a speaker system with an acoustic tube. 7 is a sound pressure frequency characteristic of the speaker system with an acoustic tube of the present invention, and 8 is a sound pressure frequency characteristic in the case of a cylindrical tube having a constant opening area. Reference numeral 9 is a peak of the sound pressure level due to resonance of the tube of the present invention, and 10 is a peak of the sound pressure level due to resonance of the cylindrical tube. From this simulation result, it is understood that the peak 9 of the sound pressure level due to the resonance of the tube of the present invention is lower by about 7 dB than the peak 10 of the cylindrical tube, and is excellent in the point that the resonance of the tube is unlikely to occur. .

In the present embodiment, the starting point of the expanded cross-sectional area is the central portion of the acoustic tube, but the effect of suppressing the resonance of the tube can be obtained at any point on the acoustic tube as the starting point of the sound. Further, in the present embodiment, the case where the amount of change in the cross-sectional area from the starting point is proportional to the square of the distance is shown.
The same effect can be obtained even if the power of 1.5, the power of 1.5, or the like is changed only slightly.

[0014]

As described above, according to the present invention, the cross-sectional area of the acoustic tube attached to the acoustic emission surface of the speaker unit is gradually expanded toward both openings, so that the resonance phenomenon of the tube occurs. It is possible to provide a speaker system with an acoustic tube that suppresses the noise and can obtain good sound reproduction without peaks and dips in the sound pressure frequency characteristics.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a speaker system with an acoustic tube according to an embodiment of the present invention.

FIG. 2 is a sound pressure frequency characteristic diagram of an embodiment of the present invention and a conventional speaker system with an acoustic tube.

FIG. 3 is a configuration diagram of a conventional speaker system with an acoustic tube.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Speaker unit 6 Acoustic tube 3 Acoustic tube input section 4 Acoustic tube output section 5 Starting point of cross-sectional area change 7 Sound pressure frequency characteristic of the present invention 8 Sound pressure frequency characteristic of a cylindrical tube 9 Peak of sound pressure frequency characteristic of the present invention 10 Peak of sound pressure frequency characteristic of cylindrical tube

Claims (2)

[Claims] 1. A speaker system with an acoustic tube configured such that a cross-sectional area of the acoustic tube attached to the acoustic emission surface of the speaker unit gradually expands toward both openings of the acoustic tube. 2. The speaker system with an acoustic tube according to claim 1, wherein the change amount of the cross-sectional area is proportional to the power of the distance.