JPH06103959B2 - Speaker system - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speaker system in which an acoustic tube that guides sound waves is arranged on the front surface of a speaker diaphragm.

Conventional technology A method of guiding a sound wave generated from the diaphragm to the opening by providing a horn or an acoustic tube on the front surface of the speaker diaphragm is to obtain a larger output sound pressure than when not using a horn or an acoustic tube. Also, it has the advantage of being able to transmit sound in a specific direction, and has been widely used in the past.

Hereinafter, a conventional speaker system having a horn and an acoustic tube will be described with reference to the drawings.

FIG. 4 is a structural sectional view of the speaker system.

In FIG. 4, 1 is a speaker unit, 2 is a back cavity, 6 is a horn, and 8 is a sound path.

The operation of the speaker system having the horn and the acoustic tube configured as described above will be described below.

A horn 6 is arranged on the front surface of the speaker diaphragm, the area of which is small near the diaphragm and gradually increases as it approaches the opening, and the back sound is radiated to the outside on the back surface of the speaker diaphragm. The back cavity 2 is arranged so as not to cause it. If the length of the horn 6 is sufficiently longer than the wavelength of the reproduction band to be reproduced, the reproduced sound pressure frequency characteristic is flat.

Problems to be Solved by the Invention However, in the above configuration, when the horn length cannot be sufficiently increased to be incorporated in the device,
The reproduced sound pressure frequency characteristic has many peaks and dips. For example, FIG. 2 shows a reproduced sound pressure frequency characteristic diagram of a speaker system having a horn and an acoustic tube. In the figure, the characteristic B is the characteristic of a conventional speaker system having a horn and an acoustic tube as shown in FIG. 4, for example. That is, if the horn length is short, the reflected wave due to the change in the acoustic impedance at the opening end is large, and the resonance phenomenon determined by the tube length occurs, so that the reproduced sound pressure frequency characteristic has many peak dips. .

In view of the above problems, the present invention provides a speaker system capable of obtaining a flat frequency characteristic without peak dips due to resonance even in a speaker system having a short horn or a short acoustic tube.

Means for Solving the Problems In order to achieve this object, the speaker system of the present invention is such that the area inside the horn or acoustic tube is small on the front side of the diaphragm and increases as it approaches the opening. The horn wall is made of sound absorbing material.

Effect The present invention effectively absorbs a reflected wave based on a change in acoustic impedance at the opening by disposing a sound absorbing material inside the acoustic tube of the horn, which is thin near the opening and thick near the diaphragm. Therefore, the peak dip is eliminated and a flat sound pressure frequency characteristic can be obtained. Further, the sound waves generated on the front surface of the diaphragm can pass through the space provided in the central portion without being blocked by the sound absorbing material, and it is possible to reproduce up to the high frequency range.

Embodiments Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a structural sectional view of a speaker system according to an embodiment of the present invention. In FIG. 1, 1 is a speaker unit, 2 is a back cavity, 3 is an acoustic tube that guides sound waves generated on the front surface of the diaphragm of the speaker unit 1, 4 is arranged inside the acoustic tube 3, and a sound path is provided at the center. The sound absorbing material 5 provided with a section is a sound path section.

The operation of the speaker system configured as above will be described below. The sound on the back surface of the diaphragm of the speaker unit 1 is closed in the cavity 2, but the sound wave radiated to the front surface of the diaphragm is guided to the opening through the acoustic tube 3 and radiated. However, due to the sudden change in acoustic impedance generated at the opening, a part of the sound wave guided to the opening becomes a reflected wave and tries to return to the diaphragm surface. The reflected wave is absorbed by the sound absorbing material arranged inside the acoustic tube to prevent the standing wave from being generated inside the acoustic tube. Further, the sound absorbing material 4 has a shape in which the thickness of the sound absorbing material near the opening is small and the thickness of the sound absorbing material near the speaker unit 1 is thick. The impedance change of
The sound absorption effect is enhanced. Further, since the sound path is provided at the center of the sound absorbing material 4, the sound wave generated from the diaphragm is guided to the opening without being blocked by the sound absorbing material 4.

FIG. 2 shows reproduced sound pressure frequency characteristics of a speaker system with a horn and an acoustic tube, comparing the present invention with a conventional example. The characteristic B in the conventional example has large peaks and valleys because a standing wave is generated in the acoustic tube, but as shown in A of the characteristic of the speaker system of the present invention, a flat reproduction sound pressure frequency characteristic can be obtained up to the high frequency range. I understand.

FIG. 3 shows a speaker system according to another embodiment of the present invention. In FIG. 3, 6 is a horn, 7 is a sound absorbing material arranged inside the horn, and 8 is a sound path portion.
The operation and effect of this embodiment are the same as those of the speaker system of the embodiment shown in FIG.

EFFECTS OF THE INVENTION As described above, according to the present invention, by adopting the structure in which the sound absorbing material is arranged inside the acoustic tube or the horn, the peak of the reproduced sound pressure frequency characteristic due to the standing wave seen in the conventional acoustic tube or the horn. -It is possible to obtain flat characteristics up to a high frequency range without causing a dip.

[Brief description of drawings]

1 is a structural sectional view of an embodiment of the speaker system of the present invention, FIG. 2 is a sound pressure frequency characteristic diagram of the speaker system, and FIG. 3 is a structural sectional view of another embodiment of the speaker system of the present invention. FIG. 4 is a structural sectional view of a conventional speaker system. 1 ... Speaker unit, 2 ... Cavity, 3 ... Acoustic tube, 4 ... Sound absorbing material, 5 ... Sound path part, 6 ... Horn, 7
…… Sound absorbing material, 8 …… Sound path part.

Claims (1)

[Claims] 1. An acoustic tube for guiding a sound wave is arranged on the front surface of a speaker diaphragm, and a sound absorbing material is thin inside the acoustic tube near the opening, and near the diaphragm. The sound path is surrounded by sound absorbing material, and the cross section of the sound path is small at the front of the diaphragm, and the sound absorbing material increases so that the cross section increases toward the opening. A speaker system comprising: