JPH0580093U - Speaker system - Google Patents

Abstract

(57) [Abstract] [Purpose] In a speaker system in which an acoustic tube is installed in the front part of the speaker diaphragm to guide the sound waves generated from the diaphragm to the opening, the sound pressure caused by the resonance mode is used without using a sound absorbing material. (EN) Provided is a speaker system in which the peaks of (1) are removed to eliminate the peaks and valleys of the reproduced sound pressure frequency characteristics. [Structure] A part of the sound wave emitted from the speaker unit 1 exerts sound pressure on the first resonance boxes 6 and 7, and the first resonance boxes 6 and 7 are again resonated at a resonance frequency determined by a volume or the like. Sound pressure is applied to the speaker unit 1 to directly correct the frequency characteristic. The sound wave affected by the sound guide portion 5 tries to return to the front surface of the speaker unit 1 because a part of the sound wave guided to the opening portion becomes a reflected wave due to a rapid change in acoustic impedance generated in the opening portion. , The second resonance tube 8 to 1
By setting the resonance frequency of 0 in advance, the energy of the reflected wave is absorbed and the generation of the standing wave is suppressed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a speaker system in which an acoustic tube for guiding sound waves is arranged on the front surface of a diaphragm of a speaker, and more particularly to a speaker system suitable for use in arranging an acoustic tube having a short length.

[0002]

[Prior Art]

 There is a conventional method of providing an acoustic tube on the front surface of the speaker diaphragm and guiding the sound waves generated from the diaphragm to the opening. Such a horn-type speaker system has good efficiency and transient characteristics, and is said to have directivity. It has characteristics. FIG. 5 is a structural sectional view showing a horn type speaker system. On the front surface of the diaphragm of the speaker unit 1, an acoustic tube 31 having a small area in the vicinity of the diaphragm and gradually increasing in size as it approaches the opening is provided as a sound guiding section 4 and a rear surface of the speaker unit 1. A back cavity 2 is arranged in the section so that the sound emitted from the back surface of the diaphragm is not emitted to the outside.

In such a horn type speaker system, if the length of the acoustic tube 31 is sufficiently longer than the wavelength of the reproduction band to be reproduced, the reproduced sound pressure frequency characteristic is flat. However, when incorporating such a horn type speaker system into a device such as a television receiver, there are cases where the horn cannot be sufficiently long. In that case, the reproduced sound pressure frequency characteristic has many peaks and valleys. Since the length of the horn is shorter than the wavelength of the reproduction band, the reflection and resonance at the opening end of the horn produce a standing wave, and as a result, the reproduced sound pressure frequency characteristics have peaks and valleys.

A speaker system that solves such a problem is disclosed in Japanese Patent Laid-Open No. 1-279698. FIG. 6 shows a structural cross-sectional view of this speaker system. Reference numeral 1 is a speaker unit, 2 is a back cavity, 32 is an acoustic tube, 4 is a sound guide portion, 5 is a partition plate, and 51 is a sound absorbing material. An acoustic tube 32 and a partition plate 5 shorter than the acoustic tube 32 are provided on the front surface of the speaker unit 1, and a sound absorbing material 51 that opens to the sound guide portion 4 is provided between the partition plate 5 and the acoustic tube 32. The sound absorbing function of the sound absorbing material 51 eliminates the peak of the sound pressure caused by the resonance mode.

[0005]

[Problems to be solved by the device]

 However, in the conventional speaker system, since the sound absorbing material 51 is used to remove the peak of the sound pressure due to the resonance mode, there is a drawback that the material cost of the sound absorbing material and the assembly cost are increased. Further, when such a loudspeaker system is mass-produced, the sound absorbing effect of the sound absorbing material 51 varies, and furthermore, the sound absorbing material 51 absorbs the mid-high frequency region having a short wavelength, so that the reflection effect of the horn decreases. There was a problem.

[0006]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems of the conventional technology, the present invention provides a speaker that converts an electric signal into a sound wave, and an acoustic tube that is provided on the front surface of the speaker and that forms a horn-shaped sound guide part to guide the sound wave. A single or a plurality of first resonance boxes provided inside the acoustic tube immediately before the speaker for directly correcting the sound pressure of the sound wave emitted from the speaker; In the space surrounded by the pipe, the inner wall surface has a port for inserting the sound guide portion, and a single or a plurality of second resonance boxes for absorbing the sound pressure of the standing wave in the acoustic pipe. It provides a characteristic speaker system.

[0007]

【Example】

 Hereinafter, a speaker system of the present invention will be described with reference to the accompanying drawings. 1 is a structural cross-sectional view showing a first embodiment of a speaker system of the present invention, FIG. 2 is a graph showing reproduced sound pressure frequency characteristics, and FIG. 3 is a second embodiment of the speaker system of the present invention. FIG. 4 is a structural cross-sectional view showing a third embodiment of the speaker system of the present invention. 3 and 4, the same parts as those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

In FIG. 1, the speaker unit 1 is attached to an acoustic tube 3, and a back cavity 2 is arranged on the back surface thereof so as not to radiate the sound emitted from the back surface of the diaphragm of the speaker unit 1 to the outside. The acoustic tube 3 is located inside the outer diameter of the diaphragm of the speaker unit 1, spreads toward the opening, and serves as a sound guide 4 that guides the sound wave emitted from the speaker unit 1. The space inside the acoustic tube 3 is arbitrarily partitioned to form resonance boxes 6 to 10 that resonate with the sound waves emitted from the speaker unit 1. The resonance boxes 6 to 10 have different volumes, and the resonance frequencies can be changed by setting them arbitrarily. In the first resonance boxes 6 and 7, the sound tube 3 is opened at the front surface of the speaker unit 1, and the second resonance boxes 8 to 10 have ports 8a to 10a on the inner wall surface of the sound tube 3. ing.

The operation of the speaker system configured as above will be described below. The sound wave emitted from the front surface of the speaker unit 1 is emitted to the outside through the sound conducting section 4, and a part of it also applies sound pressure to the first resonance boxes 6 and 7. The first resonance boxes 6 and 7 can directly apply the sound pressure to the speaker unit 1 at a resonance frequency determined by the volume and the like to directly correct the frequency characteristic of the sound wave emitted from the speaker unit 1.

The sound wave affected by the sound conducting section 4 is emitted to the outside of the acoustic tube 3 through the opening, and at that time, it is guided to the opening due to a rapid change in acoustic impedance generated in the opening. A part of the sound wave becomes a reflected wave and tries to return to the front surface of the speaker unit 1. Therefore, by setting the resonance frequencies of the second resonance tubes 8 to 10 in advance, it is possible to absorb the energy of the reflected waves and suppress the generation of standing waves. In addition, the inner wall surface of the acoustic tube 3 reflects sound waves, and the effect of reflection can be improved mainly in the mid-high frequency range where the wavelength is short.

FIG. 2 is a graph showing reproduced sound pressure frequency characteristics. Is an example of the reproduced sound pressure frequency characteristic of the type without the resonance box of the conventional example shown in FIG. 5, and is an example in which the model is corrected in this embodiment. It can be seen that the peak is suppressed at the frequency indicated by the arrow.

FIG. 3 is a structural sectional view showing a second embodiment of the speaker system of the present invention. In FIG. 3, the acoustic tube 3 is provided with first resonance boxes 11 and 12 and five second resonance boxes 13 to 17. By increasing the number of the second resonance boxes, it is possible to set a plurality of resonance frequencies and finely correct the reproduced sound pressure frequency characteristics.

FIG. 4 is a structural sectional view showing a third embodiment of the speaker system of the present invention. In FIG. 4, the acoustic tube 3 is one in which the first acoustic tubes 18 and 19 and the second resonance boxes 20, 21 and 22, 23 are connected in series by ports 21a and 23a, respectively. They are arranged one above the other. By connecting two resonance boxes in series, the bandwidth of the resonance frequency of the second resonance box can be widened.

[0014]

[Effect of the device]

 As described in detail above, since the speaker system of the present invention does not use the sound absorbing material to remove the peak of the sound pressure caused by the resonance mode, the material cost can be reduced and the acoustic tube can be formed by molding or the like. Therefore, the assembly cost can be reduced. In addition, variations in the sound absorption effect due to the sound absorbing material and reduction in the reflection effect of the horn in the middle and high frequency regions are eliminated, and the frequency characteristics of the speaker system can be set at the time of design by presetting the resonance frequency of the resonance box. It has an extremely excellent practical effect of being able to develop a speaker system with various sound quality tendencies.

[Brief description of drawings]

FIG. 1 is a structural cross-sectional view showing a first embodiment of a speaker system of the present invention.

FIG. 2 is a graph showing reproduced sound pressure frequency characteristics.

FIG. 3 is a structural sectional view showing a second embodiment of the speaker system of the present invention.

FIG. 4 is a structural cross-sectional view showing a third embodiment of the speaker system of the present invention.

FIG. 5 is a structural cross-sectional view showing a horn type speaker system.

FIG. 6 is a structural cross-sectional view showing a conventional speaker system.

[Explanation of symbols]

 1 Speaker unit 2 Back cavity 3 Acoustic tube 6,7 1st resonance box 8-10 2nd resonance box 8a-10a port

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroaki Ito 2-2-24, Nishidai, Itabashi-ku, Tokyo Within Dainichi Hibiki Co., Ltd. (72) Inventor Tomoki Matsumoto 2-24, Nishidai, Itabashi-ku, Tokyo Dainichi Hibiki Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. A speaker for converting an electric signal into a sound wave, an acoustic tube provided on the front surface of the speaker to form a horn-shaped sound guide section for guiding the acoustic wave, and provided in front of the speaker inside the acoustic tube. A single or a plurality of first resonance boxes that directly correct the sound pressure of the sound waves emitted from the speaker; and a sound guide on the inner wall surface of the space provided inside the acoustic tube and surrounded by the acoustic tube. A loudspeaker system comprising: a single resonance unit or a plurality of second resonance boxes that have a port that is inserted through the section and that absorb the sound pressure of a standing wave in the acoustic tube.