JP2008160780A - Loudspeaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a loudspeaker having preferred characteristics in sound quality, of which the volume in the low range increases, in a square cabinet. <P>SOLUTION: In a loudspeaker unit is fitted to a square cabinet, constituting a loudspeaker, a plurality of acoustic fins are fitted in an inclined manner, on the two parallel wall surfaces of the cabinet, and the acoustic fins fitted on the wall surfaces cross each other, to form a complex sound passage, with an opening part provided at the end of the sound passage. Thus, the volume in the low range increases, to provide a loudspeaker having preferred characteristics in terms of sound quality. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a loudspeaker having an increased volume feeling in a low sound range and a preferable sound quality.

In a speaker used for audio signal reproduction, a speaker unit is attached to various cabinets in order to improve reproduction characteristics in a low sound range. As a cabinet type, a bass reflex type, a horn type, an acoustic maze type, a resonance tube type and the like are well known. Of these, the bass reflex type is characterized by having a bass reflex duct inside the cabinet. As the classification by the shape of the cabinet, there are a bookshelf type with a relatively low height and a tallboy type with a high height.

The horn type, acoustic maze type, and resonance tube type (hereinafter collectively referred to as slim type) all have an elongated tubular sound path, and part or all of the sound path is formed by a cabinet wall. This is different from the bass-reflex type. It is difficult to strictly distinguish the above three types, and there may be various modifications around these.

These well-known types of cabinets require a large cabinet with a large speaker unit and a long bass reflex duct in the bass reflex type to obtain a sufficiently low volume feeling. Requires a 2 m long sound path, and even if a bent sound path is adopted, the cabinet must inevitably become large.

Problems to be solved by the invention

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a loudspeaker having a sound quality that is favorable in terms of volume in a low frequency range in a square cabinet.

Means for solving the problem

The present invention has been made to solve the above problems,
In a speaker in which a speaker unit is attached to a square cabinet, one or more acoustic fins are inclined and attached to two opposite parallel wall surfaces of the cabinet at different angles for each wall surface. The speaker is characterized in that a bent sound path is formed when the acoustic fins cross each other, and an opening is provided at the end of the sound path.

The operation of the present invention will be described below.

In a slim type such as a horn type, an acoustic maze type, and a resonance tube type, a long sound path is required to extend the low frequency range. Here, the sound path is a communication space provided as a path for sound waves radiated from the rear surface of the speaker unit, and the sound waves that have passed through the sound path pass through an opening provided at the end of the sound path from the cabinet. Released to the outside. In principle, the speaker of the present invention also enhances the low frequency by forming a long sound path as in the slim type.

The present invention is applied to a cabinet having an internal shape substantially a cube, a rectangular parallelepiped, or a polygonal cross section and parallel plane walls. These are collectively referred to as a square cabinet.

The acoustic fin used in the present invention is relatively perpendicular to or perpendicular to each of two parallel wall surfaces, for example, in the case of a rectangular parallelepiped cabinet, left and right side plates, baffle plates and back plates, bottom plates and top plates. It is a plate-like body installed at a close angle. Here, the wall surface is an inner wall of the rectangular cabinet and indicates a substantially flat surface. The shape of the acoustic fin is usually a flat rectangular or square shape, but can be changed according to the cross-sectional shape of the rectangular cabinet.

At the same time, the acoustic fin is mounted with an inclination with respect to this reference, with the base plate as the reference (zero angle). The inclination angle is different for each wall surface. Moreover, although the inclination angle may differ between the acoustic fins attached to the same wall surface, it is usually desirable that they be the same. The absolute value of the inclination angle is not less than 3 degrees and not more than 87 degrees with respect to the bottom plate. Here, the bottom plate refers to a bottom plate parallel to the floor surface in a regular installation state. However, when the fins are respectively installed on the bottom plate and the top plate, the inclination angle is an angle with reference to the baffle surface with the baffle surface regarded as a vertical plane. When the inclination angle is less than 3 degrees or exceeds 87 degrees, the effect of enhancing the low frequency according to the present invention is lost.

As described above, the acoustic fins are attached to two wall surfaces that are parallel to each other, inclined at different angles for each wall surface, and when viewed from a direction perpendicular to the wall surface, the fins attached to the front wall surface. The fins attached to the wall on the other side cross each other near the center. This state is illustrated three-dimensionally in FIG. The crossing position is not limited to the vicinity of the center, and may be shifted from the center. In addition, the crossing said by this invention shall point out crossing other than the crossing (or overlap) in the edge part of a fin.

It is desirable that the length of the acoustic fin in the attached state is substantially zero in the gap between the wall surfaces adjacent to both ends of the acoustic fin, or as small as possible in production. In the case of a cabinet having a quadrangular cross section, the width of the acoustic fin (height from the attached wall surface) is preferably 4/5 or less, or 1/10 or more of the distance between two opposing surfaces. If it is 4/5 or more, the sound path becomes narrow and the sound pressure of the sound emitted from the opening is lowered, which is not preferable. Below 1/10, the effect of acoustic fins is reduced. The width of the acoustic fin may be the same on the front side and the other side, or may be different.

FIG. 3 shows an example of the installation state of the acoustic fins in a three-dimensional manner. The speaker unit is installed in the upper part of the drawing and the opening is installed in the lower part of the drawing, both of which are not shown.
As shown in FIG. 3, inside the rectangular cabinet, a plurality of acoustic fins respectively installed on two opposing wall surfaces are successively connected while changing the inclination angle and the distance from the bottom plate to form a partition plate. A space that is sandwiched between these partition plates and communicated with each other is a bent sound path. The sound that has passed through the sound path is emitted to the outside through an opening provided at the end of the sound path.
The area of the opening is preferably in the range of 0.1 to 0.5, where the effective diaphragm area of the speaker unit is 1.

When the cabinet has a quadrangular cross section as shown in FIG. 3, the method of installing the acoustic fins only on the two surfaces facing each other is the simplest and preferable. In this example, acoustic fins having inclinations opposite to each other (plus or minus and the same absolute value) are installed on two opposing wall surfaces.

The upper and lower (or left and right) ends of the adjacent acoustic fins installed on the two opposing wall surfaces may overlap as shown in FIGS. 1 and 2, but may also be separated. Furthermore, the inclination angle may be sequentially increased from the speaker unit toward the opening, and conversely, the inclination angle may be sequentially decreased.

The invention's effect

ADVANTAGE OF THE INVENTION According to this invention, the volume feeling of a low sound region increases in a square cabinet, and the speaker which has the characteristic with preferable sound quality can be manufactured.

Hereinafter, although embodiment of this invention is described based on drawing, this invention is not limited to these embodiment.

FIG. 1 is a schematic cross-sectional view of a bookshelf type speaker according to a preferred embodiment of the present invention.

The speaker shown in FIG. 1 includes a speaker unit 1 that emits sound by converting an electrical signal into air vibration, a cabinet 2 to which the speaker unit 1 is attached, a plurality of acoustic fins 6 and 8 that constitute a partition plate, and the partition. A continuous sound path 15 formed by a plate and an opening 3 provided to release sound waves that have passed through the sound path to the outside are provided. The acoustic fin is in contact with the top plate and the bottom plate at both upper and lower ends.

In FIG. 1, the acoustic fins 8 indicate three acoustic fins attached to the front side plate (the right side plate with respect to the baffle), and all three have substantially the same inclination angle. The acoustic fin 6 refers to three acoustic fins attached to the far side plate (the left side plate with respect to the baffle), and the inclination angle is the opposite (minus) to the acoustic fin 8 and the absolute value is the same for all three. It has become. The acoustic fins 6 and 8 cross each other at the center. As a result, the sound path becomes complicated and is thought to contribute to the reduction of reverberant sound.

FIG. 2 is a specific example of a slim type speaker according to a preferred embodiment of the present invention. Each of the acoustic fins 6 and 8 is attached to both side plates and intersects with each other at the center to form a sound path 15. It differs from FIG. 1 in that the left and right ends of the acoustic fin are in contact with the baffle plate and the back plate.

The sound path 15 of the speaker according to the preferred embodiment of the present invention provides a sound pressure frequency characteristic in which the effective length of the sound path is longer than the length determined by the height or depth of the cabinet 2 and thus extends to a lower range. It is done.

FIG. 4 shows the sound pressure frequency characteristics of the mid-low range in the front of the bookshelf type speaker shown in FIG. The horizontal axis represents the frequency (Hz) of the reproduced sound wave, and the vertical axis represents the measured sound pressure level (dB). As can be seen from the figure, the reproduction frequency band in the low sound range of the present embodiment extends substantially flat up to 50 Hz, and it can be seen that it has sufficient low frequency reproduction capability.

The sound pressure frequency characteristics in FIG. 4 are measured by making a prototype of a speaker cabinet having an internal volume of 5 liters using a full-range speaker unit having an aperture of 8 cm. The external dimensions of the cabinet are a width of 140 mm, a depth of 210 mm, a height of 280 mm, and a plate thickness of 15 mm. The six acoustic fins used have the same shape, a rectangular plate having a width of 55 mm, a length of 250 mm, and a thickness of 12 mm. The mounting inclination angle is ± 80.5 degrees with respect to the bottom plate. The opening provided on the back has a diameter of 30 mm and is 0.25 times the effective diaphragm area.

FIG. 5 shows the sound pressure frequency characteristics of the mid-low range in the front of the slim speaker whose cabinet shape is shown in FIG. The horizontal and vertical axes are the same as in FIG.
As can be seen from the figure, the reproduction frequency band in the low sound range of the present embodiment extends substantially flat up to 50 Hz, and it can be seen that it has sufficient low frequency reproduction capability.

Note that the sound pressure frequency characteristics in FIG. 5 are measured by making a prototype of a speaker cabinet having an internal volume of 5.8 liters using a full-range speaker unit having an aperture of 8 cm. Except for the base 30, the cabinet has a width of 100 mm, a depth of 124 mm, a height of 800 mm, and a plate thickness of 12 mm, and is a tallboy type that is convenient to install beside a television. The ten acoustic fins used have the same shape, a rectangular plate having a width of 37 mm, a length of 160 mm, and a thickness of 12 mm. The mounting inclination angle is ± 43 degrees with respect to the bottom plate.
The opening provided in the lower end of the back has a diameter of 30 mm.

It is sectional drawing of the bookshelf type speaker using the acoustic fin of this invention. It is sectional drawing of the Tallboy type speaker using the acoustic fin of this invention. It is a perspective view of the acoustic fin in preferable embodiment of the speaker of this invention. It is a graph of the sound pressure frequency characteristic measured in the front of the bookshelf type speaker which has an acoustic fin of the present invention. It is a graph of the sound pressure frequency characteristic measured in the front of the tallboy type speaker which has an acoustic fin of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Speaker unit 2 Cabinet 3 Opening part 4 Terminal 6 Acoustic fin 8 attached to the other side board 8 Acoustic fin 15 attached to the front side board 15 Sound path 20 Bottom board 30 Base

Claims (1)

  In a speaker in which a speaker unit is attached to a square cabinet, one or more acoustic fins are inclined and attached to two opposite parallel wall surfaces of the cabinet at different angles for each wall surface. A loudspeaker having a bent sound path formed by the acoustic fins crossing each other, and an opening provided at the end of the sound path.