JP2007036921A - Bass-reflex speaker device and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for attaining the reduction of the number of parts and the improvement of assembly workability of a bass-reflex speaker box without configuring a bass-reflex duct arranged in the speaker box of the bass-reflex speaker device of the tube version components of another body. <P>SOLUTION: A half-cut bass-reflex duct is formed in the direction of a tube shaft inside either a front cabinet or a back cabinet configuring the speaker box of a bass-reflex speaker device, and the front cabinet is joined to the back cabinet so that the bass-reflex duct where the full periphery of the half-cut duct is continued can be formed. Also, a stud whose cross section is streamlined is formed perpendicularly to the tube shaft in the bass-reflex duct formed by the means so that any small animal such as insects can be prevented from intruding from the bass-reflex opening. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a bass reflex speaker device intended to improve the reproduction capability of a low frequency sound range by an audio reproduction device, and more particularly to a means for forming a bass reflex duct in a speaker box which is a component of the bass reflex speaker device.

As a means for improving the reproduction capability of the low-frequency sound range from the audio reproduction device, the vibration system including the aperture of the speaker diaphragm, the rigidity of the speaker diaphragm, the speaker diaphragm support structure, and the energizing voice coil for driving the speaker diaphragm This can be realized by housing a large-diameter speaker that maintains a minimum resonance frequency determined by factors such as the overall mass in a large-volume sealed speaker box, but a bass-reflex speaker device using Helmholtz resonance has been devised. Even in combination with a small-diameter speaker and a small-volume speaker box whose minimum resonance frequency is not sufficiently low, it is possible to realize a good low-frequency sound range reproduction characteristic.

Accordingly, the bass reflex type speaker device is a small book shelf type component audio product designed for a space-saving environment, or a speaker device incorporated in a display device in which it is difficult to secure a sufficient volume as a speaker box. Widely applied.

Sound pressure released from the front of the speaker to the outside of the speaker box, and sound released from the back of the speaker diaphragm into the speaker box and from the bass reflex opening provided in the speaker box housing to the outside of the speaker box Since the phases of the pressures are in an opposite phase relationship and cancel each other, the sound pressure particularly in a low frequency sound range is lowered. However, in the bass reflex type speaker device, one end of the bass reflex duct disposed in the speaker box shares the back space of the speaker diaphragm in the speaker box, and is released from the bass reflex opening at the other end of the bass reflex duct to the outside of the speaker box. The sound pressure emitted and the sound pressure emitted from the front of the speaker to the outside of the speaker box are superimposed and emphasized in the same phase at the Helmholtz resonance frequency.

As a first conventional example for forming a bass reflex duct disposed inside a bass reflex type speaker device, as shown in Patent Document 1, a bass reflex duct inside a speaker box composed of a front cabinet and a rear cabinet is piped. The first divided duct is divided into two parts in the axial direction, and one of the first divided ducts is integrally molded inside the rear cabinet, the second divided duct is formed as a separate part, and the first divided duct is integrally molded inside the rear cabinet. It joins to one divided duct by means such as adhesion.

As a second conventional example of the bass reflex duct forming means, as shown in FIG. 5, a tubular bass reflex duct 20c, which is a separate part formed in advance, is fitted and bonded to the recess of the rear cabinet 20h of the speaker box 20. One end of the bass reflex duct 20c is opened to the speaker back space 20b, and the other end of the bass reflex duct 20c is led to a bass reflex opening 20d provided in the front cabinet 20g of the speaker box 20. In the second conventional example, as in the first conventional example found in Patent Document 1, means for forming the bass reflex duct 20c inside the speaker box 20 constituted by the front cabinet 20g and the rear cabinet 20h is different. A body bass reflex duct 20c is required, and further, a complicated locking means such as an adhesive is required to fix the bass reflex duct 20c, which is a separate part, in the rear cabinet 20h of the speaker box 20. I was trying.
Japanese Patent Publication No. 2004-343548

  In order to form a speaker box, which is a constituent element of a bass reflex type speaker device, by thermoplastic resin molding, the bass reflex duct in the speaker box needs to be configured as a separate part due to restrictions associated with the direction of removal of the molding die. However, there is a problem that an increase in the number of parts and a complicated bonding work for joining the bass reflex duct, which is a separate part, to the speaker box are required.

  The bass reflex opening exposed to the outside of the bass reflex speaker box is covered with a net having a density that does not interfere with the propagation of sound waves from the speaker, and means for preventing insects and other small animals from entering the bass reflex opening. Although it is necessary to apply, it is not preferable to cover the bass reflex opening with an insect repellent net in order to appeal from the design side that the bass reflex speaker device is a speaker system having excellent low frequency sound range reproduction characteristics, An effective insect repellent was required in a state where an insect repellent net was not attached to the bass reflex opening.

A bass reflex type speaker box composed of a front cabinet and a rear cabinet, wherein at least one of the front cabinet and the rear cabinet is formed with a bisected bass reflex duct in the tube axis direction, the front cabinet and the rear cabinet Are joined together to form a bass-reflex duct in which the pipe wall of the half-divided bass-reflex duct is closed.

In the bass reflex type speaker box, studs are formed in a direction perpendicular to the tube axis of the bass reflex duct in the bass reflex duct to prevent entry of small animals such as insects from the bass reflex opening into the bass reflex duct.

In the bass reflex type speaker device, the cross-sectional shape of the stud formed in the bass reflex duct is formed to be streamlined along the propagation direction of the sound wave from the speaker, and the stud has a low-frequency sound wave having a large amplitude. Attenuating the output of the low frequency sound range by becoming a propagation resistance is avoided, and the enhancement effect of the desired low frequency sound range is improved.

In order to form a speaker box, which is a constituent element of a bass reflex type speaker device, by molding a thermoplastic resin, the bass reflex duct in the speaker box needs to be configured as a separate part due to restrictions associated with the direction of removal of the molding die. However, by forming a bisected bass reflex duct in the tube axis direction in at least one of the front cabinet and the rear cabinet constituting the bass reflex type speaker box, and joining the front cabinet and the rear cabinet together. Forming a tubular bass reflex duct with the tube wall of the half-reformed bass reflex duct closed, reducing the number of parts and complicated bonding for joining the separate bass reflex duct inside the speaker box Work is unnecessary.

By disposing studs with a streamlined cross-sectional shape in a direction perpendicular to the tube axis of the bass reflex duct so as not to hinder the propagation of sound waves in the low frequency range in the bass reflex duct near the bass reflex opening Thus, it is possible to prevent small animals such as insects from entering the bass reflex duct from the bass reflex opening, avoid deterioration of characteristics during long-term use as a speaker device, and improve reliability.

A case where the embodiment of the present invention is applied to a liquid crystal television will be described below with reference to the drawings. FIG. 1 is an external view of a liquid crystal television according to the present invention. 1 is a liquid crystal display panel for displaying an image, 2 is a front cabinet, 3 is a rear cabinet, and 9 is a speaker panel 2a constituting a part of the front cabinet 2. The speaker opening provided, 4 is a bass reflex opening, 6 is a stand, and 7 is a carrying handle.

FIG. 2 is a perspective view showing a schematic configuration inside the liquid crystal television with the rear cabinet 3 of the liquid crystal television removed. Inside the front cabinet 2, a liquid crystal display panel 1 and a backlight unit 5 for irradiating light from the back surface of the liquid crystal display panel 1 are disposed. On both the left and right sides of the liquid crystal display panel 1, speaker boxes 8 having the same acoustic characteristics are disposed in a positional relationship that is axisymmetric with respect to the vertical line at the center of the display screen of the liquid crystal display panel 1 in order to realize a stereo acoustic effect. Has been.

Next, the speaker box 8 which is the 1st Embodiment of this invention is demonstrated based on FIG. FIG. 3 is a perspective view in which the speaker box 8 of the bass reflex type speaker device is disassembled into a front cabinet 8g shown in FIG. 3 (a) and a rear cabinet 8h shown in FIG. 3 (b). A speaker 8a is attached above the front cabinet 8g, and a bass reflex opening 8d is formed below. The bass reflex opening 8d is equipped with an insect net for preventing invasion of insects and other small animals in order to appeal from the design and design viewpoint that the bass reflex speaker device is a speaker system having excellent low frequency sound range reproduction characteristics. Absent.

FIG. 3B is a perspective view of the rear cabinet 8h of the speaker box 8 constituting the bass reflex speaker device. A speaker rear space 8b having a large volume is formed at a position corresponding to the rear portion of the speaker 8a. One end of a bass reflex duct 8c having a semicircular cross section is opened in the speaker back space 8b. The other end of the bass reflex duct 8c is led to a bass reflex opening 8d formed in the front cabinet 8g. The volume of the speaker back space 8b and the cross-sectional area and pipe length of the bass reflex duct 8c are designed according to the formula for the resonance frequency of the Helmholtz resonator.

The bass reflex duct 8c with a part of the pipe wall opened has both ends of the pipe axis of the bass reflex duct 8c opened by joining the front cabinet 8g to the rear cabinet 8h as shown by a chain line arrow in FIG. The tube wall is closed and a tube-type bass reflex duct is formed.

As described above, an insect repellent net for preventing insects and other small animals from entering from the bass reflex opening 8d is not attached to the bass reflex opening 8d for the reason of design design. For this reason, as shown in FIG. 3B, studs 8e are formed in the bass reflex duct 8e at the connecting portion between the bass reflex opening 8d and the bass reflex duct 8c that are not visually recognized by the viewer from the front of the bass reflex opening 8d.

FIG. 4 is a detailed explanatory view of the stud. When the cross-sectional shape of the stud 21 is rectangular or rectangular as shown in FIG. 4C, turbulent flow is generated on the front end surface 21a of the stud 21 by sound waves passing around the stud 21, and the rear end surface 21b of the stud 21 is formed. Then, negative pressure is generated and smooth sound wave propagation is inhibited. As a result, the output in the low frequency sound range from the bass reflex opening is attenuated, or wind noise is generated. However, in the second embodiment of the present invention, when the cross-sectional shape of the stud 8e is streamlined as shown in FIG. 4 (b) as shown in FIGS. 4 (a) and 4 (b), the periphery of the stud 8e is shown. Sound waves that pass through the sound propagate smoothly and do not attenuate the output in the low frequency range.

The present invention is not limited to a bass reflex duct of a bass reflex type speaker device having a relatively simple shape such as a straight tube type or an L-shaped bent tube shown in FIG. 3, and is incorporated in a thin or small display device. In the bass reflex type speaker device, it is difficult to secure a sufficiently long duct length as the bass reflex duct, and it is more effective when a zigzag duct shape in which the duct is folded back many times is applied.

It is the front view and side view of the external appearance of the liquid crystal television concerning this invention. It is the back perspective view inside this liquid crystal television which removed the back cabinet of the liquid crystal television which is an example of the present invention. FIG. 3A is an exploded perspective view of the front cabinet and FIG. 3B is an exploded perspective view of the rear cabinet for explaining the first embodiment of the present invention relating to the bass reflex type speaker box. 4 (a) and 4 (b) show a second embodiment of the present invention relating to a stud, and FIGS. 4 (c) and 4 (d) show a comparative example. FIG. 4A is a front view, FIG. 4B is a bottom view, and FIG. 4C is FIG. It is a longitudinal cross-sectional view along chain line CC shown in (a).

Explanation of symbols

1: LCD panel 2: Front cabinet 2a: Speaker panel 3: Rear cabinet 4: Bass reflex opening 5: Backlight unit 6: Stand 7: Carrying handle
8: Speaker box 8a: Speaker 8b: Speaker rear space 8c: Bass reflex duct 8d: Bass reflex opening 8e: Stud 8f: Box mounting hole 8g: Front cabinet 8h: Rear cabinet 9: Speaker opening 20: Speaker box 20a: Speaker 20b : Speaker rear space 20c: Bass reflex duct 20d: Bass reflex opening 20e: Insect net 20f: Box mounting hole 20g: Front cabinet 20h: Rear cabinet 21: Stud 21a: Front end surface 21b: Rear end surface

Claims (6)

In a bass reflex type speaker device constituted by a front cabinet and a rear cabinet, a bass reflex duct that is halved in the tube axis direction is formed inside at least one of the cabinets, and the front cabinet and the rear cabinet are joined together. A bass reflex type speaker device characterized by forming a desired bass reflex duct. 2. The bass reflex type speaker device according to claim 1, wherein a stud is formed at a position close to at least one port opening in the bass reflex duct in a direction perpendicular to the tube axis of the bass reflex duct. Type speaker device. The bass reflex type speaker device according to claim 2, wherein the stud is formed integrally with a material of the cabinet. 3. The bass reflex type speaker device according to claim 2, wherein the stud is provided at a position where the stud is not viewed directly when viewed from the external opening surface side of the bass reflex duct. 5. A bass reflex speaker device according to claim 2, wherein a cross-sectional shape of a stud formed in the bass reflex duct is formed to be streamlined along a sound wave propagation direction. Type speaker device. A display device equipped with a speaker device, wherein the bass reflex speaker device according to any one of claims 1 to 3 is provided.

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