JP2008079268A - Speaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a speaker which has preferable characteristics in sound quality by increasing a sense of lower register volume even in a rectangular small-sized cabinet. <P>SOLUTION: A speaker with a speaker unit mounted to a rectangular cabinet is constituted so that a plurality of acoustic fins are attached to a wall surface of the cabinet while being inclined, a rectangular three-dimensional helical sound path is formed from the acoustic fins, and an opening is provided at a terminal of the helical sound path. Thus, the speaker can be provided which has preferable characteristics in sound quality by increasing a sense of lower register volume even in a small-sized cabinet. <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 a form that reinforces the low range by utilizing Helmholtz resonance and is characterized by having a bass reflex duct inside the cabinet.

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. It is a feature. It is difficult to strictly distinguish the above three types, and there may be various modifications around these. For example, the TLS type attracting attention in recent years is a horn type, an acoustic maze type, a resonance tube type, or a modified type of the sound path filled with a sound absorbing material, and these three types (slim type) are included. And

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.

On the other hand, a speaker having a three-dimensional spiral sound path was invented by the present inventor as a method for solving these problems and obtaining a sufficient volume feeling in a low frequency range even in a small cabinet (see Patent Document 1). A three-dimensional helix was defined as a trajectory in which rotation about one axis and translation along that axis are performed simultaneously and continuously. The locus is formed by a smooth curve. In this method, even in a relatively small cabinet, it is possible to incorporate a duct equivalent to a long bass reflex duct and a long sound path in a slim type cabinet, so that a good sound quality with sufficiently extended low range can be obtained. However, there is a problem that it cannot be applied to a rectangular bass reflex duct or a rectangular slim cabinet.
Japanese Patent No. 3747392

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 that has a low-frequency volume feeling even in a small rectangular cabinet and has favorable sound quality characteristics.

Means for solving the problem

The present invention has been made to solve the above problems,
In the speaker where the speaker unit is attached to the square cabinet,
A plurality of acoustic fins are inclined and attached to the wall surface of the cabinet, a square three-dimensional spiral sound path is formed by the acoustic fins, and an opening is provided at the end of the spiral sound path. It is a speaker.

The operation of the present invention will be described below.

In the bass reflex type, a long duct is required to extend the Helmholtz resonance frequency to a sufficiently low frequency range. The duct corresponds to the neck portion of the Helmholtz resonator, and the conventional duct that has been conventionally used is a hollow tubular body having a square cross section such as a circle or a square, and is emitted from the rear surface of the speaker unit. The sound wave passes through the duct and is emitted to the outside of the cabinet through an opening provided at the end of the duct.

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.

The acoustic fin used in the present invention is a wall surface of a rectangular bass reflex duct and a rectangular slim cabinet (hereinafter collectively referred to as a square cabinet including a square bass reflex duct), for example, left and right side plates, baffle plates and It is installed at an angle that is substantially vertical or relatively close to vertical on each wall surface of the back plate. Here, the wall surface refers to an inner wall of a rectangular cabinet that is substantially flat and excludes a bottom plate and a top plate. 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 fins are attached to the surface perpendicular to the central axis of the bass reflex duct or inclined to the bottom plate of the rectangular cabinet (hereinafter collectively referred to as the bottom plate). The absolute value of the inclination angle is not less than 0 degrees and not more than 80 degrees with respect to the bottom plate. Here, the acoustic fins allowed to have an inclination angle of 0 degree must be a part of the plurality of acoustic fins. The bottom plate refers to a bottom plate parallel to the floor surface in a regular installation state.

It is desirable that the length of the acoustic fin is substantially zero in the attached state, or is small as long as it can be manufactured. 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 1/2 or less of the distance between the two opposing surfaces and 1/10 or more. If it is 1/2 or more, the production is relatively difficult, and if it is 1/10 or less, the effect of the acoustic fin is reduced.

As shown in FIG. 3, a plurality of the above-described acoustic fins installed on two opposing wall surfaces are successively connected while changing the inclination angle and the distance from the bottom plate in the rectangular cabinet. A spiral partition plate is formed. It is a form reminiscent of emergency staircases in mid-to-high-rise apartments. Here, the square three-dimensional spiral refers to an emergency staircase-like state in which the acoustic fins installed inclined on the wall surface of the square cabinet sequentially change the inclination angle or direction according to the wall surface, and at the same time the distance from the bottom plate changes. Shall. A space which is sandwiched between and communicated with the square three-dimensional spiral partition plate is a square three-dimensional spiral sound path. The sound wave that has passed through the sound path is emitted to the outside through an opening provided at the end of the sound path.
Here, the emergency staircase-like state means that the mutual positional relationship between adjacent acoustic fins does not produce a step difference in up and down, and is connected smoothly.

In the case of a rectangular 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 opposite inclinations (plus or minus and the same absolute value) are installed on two opposing wall surfaces to form a square three-dimensional spiral partition plate.

Another example of the above-mentioned square three-dimensional spiral partition plate is as shown in FIG. 4 by acoustic fins installed on each wall surface of a quadrangular section. An inclination angle of 0 degree) can also be provided.

Adjacent acoustic fins may be installed with some steps as shown in FIG. That is, a step is allowed if it is not upside down. Furthermore, as shown in FIG. 6, the inclination angle may be increased sequentially from the speaker unit toward the opening. Although not shown, the inclination angle may be decreased sequentially. In either case, the distance from the bottom plate must be changed sequentially and installed at an angle that draws a smooth spiral in a substantially possible range.

In the present invention, the square refers to a polygonal duct or cabinet such as a triangle, a quadrangle, a pentagon, or a hexagon formed by a substantially flat surface. The acoustic fins do not have to be installed on all the wall surfaces, and may be flying, but they must be installed on at least two surfaces.

The invention's effect

ADVANTAGE OF THE INVENTION According to this invention, the volume feeling of a low sound region increases in a square-shaped small cabinet, and the speaker which has a favorable characteristic in 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 slim 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, and a plurality of acoustic fins 6 that form a square three-dimensional spiral partition plate. , 8, a square three-dimensional spiral sound path 15 that is formed by the partition plate, and an opening 3 that is provided to release sound waves that have passed through the sound path to the outside.

In FIG. 1, acoustic fins 6 indicate six acoustic fins attached to the front side plate (the right side plate with respect to the baffle), and all of the six fins have substantially the same inclination angle. The acoustic fins 8 indicate six acoustic fins attached to the side plate on the far side (the left side plate with respect to the baffle), and the inclination angle is the opposite (minus) to the partition plate 6 and the absolute value is the same. It has become.

FIG. 2 is a specific example of a bass reflex type speaker according to a preferred embodiment of the present invention, and shows that the speaker unit is a two-way system including a woofer 1a and a tweeter 1b. A duct 4 having a quadrangular cross-sectional shape is disposed inside the cabinet 2, and an opening 3a is provided at the end thereof. Inside the duct 4, a rectangular three-dimensional spiral is formed by a rectangular three-dimensional spiral partition plate composed of two acoustic fins 6a attached to the front side plate and three acoustic fins 8a attached to the far side plate. A sound path 15 is formed. The acoustic fins 6a and the acoustic fins 8a are attached in opposite directions (plus and minus) with the same absolute angle.

The speaker's square three-dimensional spiral sound path 15 according to the preferred embodiment of the present invention makes the effective length of the sound path longer than the length determined by the height of the cabinet 2 and the length of the square bass reflex duct 4, and thus lower. A sound pressure frequency characteristic extending to a range is obtained.

FIG. 7 shows the sound pressure frequency characteristics of the mid-low range in the front of the slim 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.

These frequency characteristics were measured by making a prototype of a speaker cabinet having an effective internal volume of 5.3 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, and a height of 800 mm, and is a slim type that is convenient to install beside a television. The 12 acoustic fins used have the same shape, the width is 37 mm, the length is 110 mm, the thickness is 12 mm, and the mounting inclination angle is ± 26 degrees. The opening provided at the lower end of the back is 45 mm × 65 mm.

FIG. 8 shows the sound pressure frequency characteristics of the mid-low range in front of the speaker according to the present embodiment of the bass reflex type, which is almost the same as in FIG. 2, except that the 8 cm full range unit is used. 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.

The sound pressure frequency characteristics shown in FIG. 8 were obtained using the following prototype speaker. The effective internal volume of the cabinet is 3.3 liters, and the external dimensions are as small as 140 mm in width, 210 mm in depth, and 280 mm in height. The inner dimensions of the duct are 75 mm in height, 75 mm in depth, and 150 mm in length, and are mounted horizontally inside the cabinet.
The dimension of the opening provided in the back wall which is the end of the duct is 75 mm × 75 mm.

A total of four acoustic fins are attached to the inside of the duct, two on the front side and two on the other side. The absolute value of the inclination angle of the acoustic fin with respect to the plane perpendicular to the central axis of the duct increases sequentially from the entrance to the exit of the duct, and is +22 degrees, −25 degrees, +28 degrees, and −31 degrees, respectively. The four acoustic fins have the same width of 37 mm and a thickness of 8 mm. The length of the acoustic fin was determined according to the inclination angle so that there was almost no gap between the upper and lower surfaces.

It is sectional drawing of the slim type speaker using the acoustic fin of this invention. It is sectional drawing of the bass-reflex type speaker using the acoustic fin of this invention. FIG. 3 is a perspective view of a square three-dimensional spiral sound path in a preferred embodiment of the speaker of the present invention. FIG. 6 is a perspective view of a rectangular three-dimensional spiral sound path in another preferred embodiment of the speaker of the present invention. It is sectional drawing of the slim type speaker of other preferable embodiment using the acoustic fin of this invention. It is sectional drawing of the slim type speaker of other preferable embodiment using the acoustic fin of this invention. It is a graph of the sound pressure frequency characteristic measured in the front of the slim 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 bass reflex type speaker which has an acoustic fin of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Speaker unit 1a Woofer 1b Tweeter 2 Cabinet 3 Opening part 3a Bass reflex duct opening 4 Bass reflex duct 6 Acoustic fin 6a attached to front side plate 7a Sound fin 7 attached to front side plate of duct 7 Inclination angle 0 acoustic fin 8 Acoustic fin 8a attached to the other side plate 8a Acoustic fin 15 attached to the other side plate of the duct 15 Square three-dimensional spiral sound path 20 Bottom plate 30 Pedestal

Claims (1)

  In a speaker in which a speaker unit is attached to a square cabinet, a plurality of acoustic fins are attached to the wall surface of the cabinet at an inclination, and a square three-dimensional spiral sound path is formed by the acoustic fins, and the spiral sound path A speaker characterized in that an opening is provided at the end of the speaker.