JP2015019245A - Bass reflex port - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure a degree of freedom for designing a sectional shape of a bass reflex port and to suppress resonance of a wall body forming the bass reflex port.SOLUTION: A portion in which resonance may occur at a maximum is a wall body portion of lowest rigidity, namely, a longest wall body portion on a cross section among a plurality of wall body portions with angular or bent parts on both ends. At least, such a wall body portion is formed in a curved line shape and rigidity is improved. Therefore, since the wall body is curved, rigidity is high and resonance is unlikely to occur with wind noise or speaker noise. Furthermore, even if there is no space within an enclosure, for example, the cross section is formed flat, such that the sectional shape can be relatively freely changed while maintaining a sectional area sufficient for bass enhancement effects.

Description

  The present invention relates to the structure of a bass reflex port.

  2. Description of the Related Art A phase inversion type speaker device having a speaker unit and a bass reflex port is known as a speaker device that enhances the volume of a low sound range. The bass reflex port has an opening connected to the surface of the enclosure and a hollow cylindrical portion provided inside the enclosure. The bass range is enhanced by the action of Helmholtz resonance that correlates with the air spring in the enclosure and the air mass in the bass reflex port (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 2-274096

  Here, FIG. 7 shows a cross-sectional view of a conventional bass reflex port, and shows a cross-sectional shape perpendicular to the extending direction of each bass reflex port. As shown in FIG. 7, there are a bass-reflex port a having a circular cross section, an elliptical bass-reflex port b, a track-type elliptical bass-reflex port c, and a rectangular bass-reflex port d. Among them, the bass reflex port a and the elliptical bass reflex port b having a circular cross section have a higher rigidity than the case where the wall body is planar because the entire wall body constituting the tubular portion is curved. There is an advantage that it is difficult to resonate with a cutting sound or speaker sound. However, if there is not enough space in the enclosure, the cross-sectional area of the bass reflex port can only be reduced by the space, so that sufficient resonance space for the bass enhancement effect may not be secured. . Further, the track-type elliptical bass reflex port c and the rectangular bass reflex port d have, for example, a flatter cross-sectional shape according to the space in the enclosure, while maintaining a sufficient cross-sectional area for the bass enhancement effect, There is an advantage that the cross-sectional shape can be changed relatively freely. However, as schematically shown in FIG. 8, the wall constituting the cylindrical portion has a relatively wide plane portion, and the rigidity of the plane portion is lower than that of the curved portion. On the other hand, there is a problem that it tends to resonate.

  Therefore, an object of the present invention is to secure the degree of freedom in designing the cross-sectional shape of the bass reflex port and to suppress the resonance of the wall body constituting the bass reflex port.

  The present invention is a hollow bass reflex port provided in a speaker device, and in a cross section perpendicular to the extending direction of the bass reflex port, at least the longest wall among a plurality of wall portions having corners or bent portions at both ends. The bass reflex port is characterized in that the cross-sectional shape of the body part is a curved shape that is convex or concave with respect to the resonance space of the bass reflex port.

  In the above configuration, it is desirable that a radius of curvature in the curved shape is larger than r, where r is a half of the distance between both ends.

  In the above configuration, it is preferable that the cross-sectional shape of the plurality of wall portions is a curved shape that is convex or concave with respect to the resonance space of the bass reflex port.

  Further, the present invention is a hollow bass reflex port provided in a speaker device, which is convex or concave with respect to a wall portion and a resonance space of the bass reflex port that are linear in a cross section perpendicular to the extending direction of the bass reflex port. A bass reflex port comprising a wall portion having a curved shape, wherein the linear wall portion is curved along the extending direction.

  In the above configuration, the cross-sectional shapes of the wall body portions at different positions in the extending direction of the bass reflex port are different, and the wall body portions having different cross-sectional shapes may be connected by curved wall body portions. .

  ADVANTAGE OF THE INVENTION According to this invention, while ensuring the design freedom of the cross-sectional shape of a bass-reflex port, resonance of the wall body which comprises a bass-reflex port can be suppressed.

It is sectional drawing of the speaker apparatus which concerns on embodiment. It is an example of a sectional view and a perspective view of a bass reflex port. It is another example of sectional drawing of a bass reflex port. It is another example of sectional drawing and a perspective view of a bass reflex port. It is another example of sectional drawing and a perspective view of a bass reflex port. It is another example of the perspective view of a bass reflex port. It is sectional drawing of the conventional bass reflex port. It is a schematic diagram explaining a mode that the conventional bass reflex port resonates.

  A speaker device according to an embodiment of the present invention will be described. FIG. 1 is a cross-sectional view of the speaker device 1 according to the present embodiment. As shown in FIG. 1, the speaker device 1 includes a speaker unit 3 provided in the enclosure 2, a bass reflex port 4 built in the enclosure 2, and an amplifier unit 6 built in the enclosure 2. The enclosure 2 includes a front plate 2a and a back plate 2b, a top plate 2c and a bottom plate 2d, and a pair of side plates (FIG. 1 shows a cross section parallel to the side plates, so that the side plates are not shown). Yes. The bass reflex port 4 is constituted by a hollow cylindrical wall body 4c having openings 4a and 4b provided at both ends. One opening 4a is connected to a front plate 2a that functions as a baffle plate. The other opening 4 b is open toward the internal space of the enclosure 2. The volume of the internal space (resonance space) where resonance occurs in the bass reflex port 4 is determined based on the frequency of the sound to be enhanced.

  FIG. 2 is an example of a cross-sectional view and a perspective view of the bass reflex port 4. The cross-sectional view shows a cross section taken along line Y-Y ′ of the perspective view, that is, a shape of a cross section perpendicular to the extending direction of the bass reflex port 4. The cross-sectional shape of the bass reflex port 4 is a combination of four wall portions each having a curved shape. When the radius of curvature of these curved wall portions is small, the rigidity becomes high and the problem of resonance with wind noise and speaker sound is unlikely to occur. However, when there is no room in the enclosure 2, the bass reflex port 4 (The area surrounded by the inner wall surface of the bass reflex port 4, that is, the area of the resonance space area in the cross section perpendicular to the extending direction of the bass reflex port 4) must be reduced. On the other hand, when the curvature radius of these curved wall portions is increased in accordance with the space in the enclosure 2, the shape of the wall portions approaches a plane and the rigidity is lowered, and the above-described resonance is likely to occur.

  Therefore, in the present embodiment, each curved line forming the resonance space 5 of the bass reflex port 4 (that is, the inner wall surface of the bass reflex port 4) has a curved shape. Specifically, when r is 1/2 of the distance between both ends of the curve corresponding to the inner wall surface, the condition that the radius of curvature in the curve is larger than r is a minimum condition to be satisfied. That is, the curve corresponding to the inner wall surface is a gentler curve than the perfect circle (curvature radius = r).

  Further, in the example of FIG. 2, a condition that makes the curve shape gentler than the above-mentioned minimum condition is followed. That is, when the length of the line segment connecting both ends of the curve corresponding to the inner wall surface of the bass reflex port 4 is A, and the longest distance from the line segment A to the curve (referred to as the bulge amount) is d, 0 is obtained. The condition is that the relational expression <d ≦ A × 1/10 is satisfied. That is, the value of the bulge amount d is relatively small. In this way, since the wall 4c is curved to some extent, it is possible to maintain rigidity that is difficult to resonate. At the same time, even if there is no room in the enclosure 2, for example, by taking a flat cross-sectional shape, the cross-sectional shape is relatively maintained while maintaining a sufficient cross-sectional area for bass enhancement. You can change it freely. In the wall body 4c, the inner diameter of the wall body 4c gradually increases as it approaches the openings 4a and 4b. This is to suppress air turbulence, and is essential in the present invention. It is not a structure.

  In FIG. 2, the wall 4 c has a curved shape that is concave with respect to the resonance space 5 of the bass reflex port 4, but on the contrary, it may have a convex curved shape. FIG. 3 shows an example of a curved shape in which the wall portions facing each other are concave and convex with respect to the resonance space 5 of the bass reflex port 4. Whether the curved shape is concave or convex with respect to the resonance space 5 of the bass reflex port 4 depends on the empty space in the enclosure 2 and the volume of the resonance space 5 necessary for the bass enhancement effect. This should be determined in consideration of

  In FIGS. 2 and 3, the cross-sectional shape of the plurality of wall portions having corners or bent portions at both ends is a curved shape that is convex or concave with respect to the resonance space 5 of the bass reflex port 4. Here, the “corner portion” is a portion at the apex of the cross-sectional shape or a pointed shape because the change in curvature is discontinuous in the cross-sectional shape. In addition, the “bent part” is a part that is curved but has a sharp curve compared to the case where the change in curvature is continuous because the change in curvature is discontinuous. .

  Resonance is most likely to occur in the wall portion having the lowest rigidity among the plurality of wall portions having corners or bent portions at both ends, that is, the longest wall portion in the bass reflex port section. Since the longest wall body is disadvantageous in terms of strength, at least the wall body portion may be curved to increase the rigidity. Accordingly, in the present invention, at least the longest wall body portion of the plurality of wall body portions having the corners or the bent portions at both ends may be a curved shape.

  FIG. 4 is another example of a cross-sectional view and a perspective view of the bass reflex port 4. In this example, the cross-sectional shape of the bass reflex port 4 is a combination of three curved wall portions. Also in this case, when the length of a line segment connecting both ends of the curve (the above-described corner or bend) is A, and the bulge amount that is the longest distance from the line segment A to the curve is d, The relational expression of 0 <d ≦ A × 1/10 is satisfied. Depending on the empty space in the enclosure 2, the wall body 4 c may be configured by three curved wall portions as shown in FIG. 4. Moreover, although illustration is abbreviate | omitted, you may comprise the wall body 4c by the wall body part of five or more curved shapes.

  As described above, as shown in FIGS. 2 to 4, at least the longest cross-sectional shape of the plurality of wall bodies having the corners or the bent portions at both ends in the cross section perpendicular to the extending direction of the bass reflex port 4 is as follows. The curved shape is convex or concave with respect to the resonance space 5 of the bass reflex port 4. On the other hand, the bass reflex ports a and b shown in FIG. 7 have a constant radius of curvature or are continuous, and therefore have no corners or bent portions. Therefore, these are inferior in design freedom of the cross-sectional shape of the bass reflex port as compared with the present embodiment. Further, the bass reflex ports c and d shown in FIG. 7 are more likely to resonate than the present embodiment because the longest wall portion has a straight cross-sectional shape.

  FIG. 5 is another example of a cross-sectional view and a perspective view of a bass reflex port. As shown in the cross-sectional view of FIG. 5, the wall body 4c includes a wall body portion 4c1 having a linear shape and a wall body portion 4c2 having a curved shape. Of the wall body portion 4c1 and the wall body portion 4c2, the wall body portion 4c1 having a linear shape has low rigidity and is likely to resonate. Therefore, as shown in the perspective view of FIG. 5, the wall portion 4 c 1 is curved along the extending direction of the bass reflex port 4. In this way, the wall portion 4c1 that is linear when viewed in cross section is curved in the extending direction of the bass reflex port 4, so that the rigidity is increased and the occurrence of resonance is suppressed. Further, by changing the extending direction of the bass reflex port 4 so as to pass through a vacant space in the enclosure 2, the vacant space can be used effectively.

  FIG. 6 is another example of a perspective view of a bass reflex port. As shown in FIG. 6, the bass reflex port includes wall portions 4A and 4B having different cross-sectional shapes at different positions in the extending direction. The wall portions 4A and 4B are connected by a curved wall portion 4C. By connecting the wall portions having different shapes in this way, the rigidity of the entire wall body is increased, and the occurrence of resonance is suppressed. Further, by changing the extending direction of the bass reflex port 4 so as to pass through a vacant space in the enclosure 2, the vacant space can be used effectively.

In the above description, the example in which the opening of the bass reflex port 4 is connected to the front plate is shown, but it may be connected to another plate surface constituting the enclosure 2.
Further, the curve shape of the wall portion is such that the radius of curvature in the curve shape is larger than r when 1/2 of the distance between both ends is r, or 0 <d ≦ A × 1/10 described above. The above example is not limited as long as the relational expression is satisfied. For example, a curved shape corresponding to a catenary line may be used.

DESCRIPTION OF SYMBOLS 1 ... Speaker apparatus, 2 ... Enclosure, 2a ... Front plate, 2b ... Back plate, 2c ... Top plate, 2d ... Bottom plate, 3 ... Speaker unit, 4 ... Bass reflex port, 4a, 4b ... opening, 4c ... wall, 5 ... resonance space.

Claims (5)

A hollow bass reflex port provided in the speaker device,
In the cross section perpendicular to the extending direction of the bass reflex port, the cross-sectional shape of at least the longest wall body portion out of the plurality of wall portions having corners or bent portions at both ends is convex or convex with respect to the resonance space of the bass reflex port. Bass reflex port, which has a concave curved shape. The bass reflex port according to claim 1, wherein a radius of curvature in the curved shape is larger than r, where r is a half of the distance between the both ends. The bass reflex port according to claim 1 or 2, wherein the cross-sectional shape of the plurality of wall portions is a curved shape that is convex or concave with respect to the resonance space of the bass reflex port. A hollow bass reflex port provided in the speaker device,
It consists of a wall portion that is a straight shape in a cross section perpendicular to the extending direction of the bass reflex port and a wall portion that is a curved shape that is convex or concave with respect to the resonance space of the bass reflex port,
The bass reflex port, wherein the linear wall portion is curved along the extending direction. The cross-sectional shape of the wall part at different positions in the stretching direction of the bass reflex port is different,
The bass reflex port according to any one of claims 1 to 4, wherein the wall portions having different cross-sectional shapes are connected by curved wall portions.

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