JP5867705B2 - Speaker cabinet and speaker - Google Patents

Description

  The present invention relates to a technique for optimizing the frequency characteristics of a speaker.

  Some sealed speakers have a structure in which a hollow rectangular parallelepiped member is used as a speaker cabinet, and a speaker unit is fitted into a baffle surface which is a front surface of the cabinet. In this type of speaker, the diffracted sound of the sound radiated forward from the speaker unit is reflected at each point on the baffle surface, and the reflected sound at each point is re-radiated forward. A direct sound radiated from the speaker unit and a reflected sound reflected at each point on the baffle surface reach each listening point in front of the speaker. For this reason, a dip or a peak occurs in the frequency response of the acoustic transmission system from the speaker to the listening point, and the acoustic characteristics at the listening point may deteriorate. In this type of speaker, the sound radiated rearward from the speaker unit is reflected back and forth between the parallel facing walls in the speaker cabinet. For this reason, the sound of a specific frequency may generate a standing wave in the cabinet, thereby deteriorating the acoustic characteristics of the listening point.

  FIG. 6 is a diagram showing a configuration example of a conventional speaker 5 suitable for preventing deterioration of acoustic characteristics caused by such reflected waves on the baffle surface of diffracted sound and standing waves in the cabinet. FIG. 7 is a longitudinal sectional view of the speaker 5. The speaker cabinet 51 of the speaker 5 has a hollow and substantially egg shape. The outer shell wall 52 of the speaker cabinet 51 has a substantially uniform thickness. A hole 53 is provided in front of the speaker cabinet 51. A speaker unit 54 is fitted in the hole 53. A leg 55 that supports the speaker cabinet 51 is fixed to a lower portion of the outer surface of the speaker cabinet 51.

  In this speaker 5, the diffracted sound of the sound radiated forward from the speaker unit 54 is reflected toward the side or rear of the speaker cabinet 51 at each point around the speaker unit 54 on the outer surface of the speaker cabinet 51. The For this reason, peaks and dips due to diffracted sound are less likely to appear in the frequency response at the listening point in front of the speaker unit 54. Further, in this speaker 5, since there are almost no parallel inner wall pairs in the speaker cabinet 51, the sound radiated backward from the speaker unit 54 is difficult to reciprocate and reflect in the speaker cabinet 51. A standing wave is less likely to be generated in 51. Patent documents 1 and 2 are documents disclosing the technology related to the speaker 5 having the configuration shown in FIGS. 6 and 7.

JP 2002-247675 A JP 2001-78285 A

  However, in the case of a conventional speaker, since the speaker cabinet is composed of a uniform thick egg-shaped outer shell wall, processing such as attaching a bass reflex port to the speaker cabinet is difficult, and design diversification is also difficult. There is a problem that there is.

  The present invention has been made in view of such problems, and it is possible to prevent deterioration of acoustic characteristics due to diffracted sound from the speaker unit and deterioration of acoustic characteristics due to the influence of standing waves in the speaker cabinet. An object of the present invention is to provide a speaker cabinet that can be used.

  According to the present invention, there is provided an outer shell wall in which a speaker unit mounting hole for mounting a speaker unit is formed in a front surface portion and a cavity communicating with the speaker unit mounting hole and having a small number of opposed parallel surfaces is formed inside. A front region of the outer shell wall in the vicinity of the speaker unit mounting hole is retracted rearward as the outer surface of the outer shell wall is separated from the speaker unit mounting hole, and the front region of the outer shell wall is The speaker cabinet is characterized in that the outer surface of the rear region farther from the speaker unit mounting hole has a shape similar to the inner surface facing the cavity inside the outer shell wall.

  In the present invention, in the outer shell wall of the speaker cabinet, the front region in the vicinity of the speaker unit mounting hole retreats backward as the outer surface of the outer shell wall moves away from the speaker unit mounting hole. For this reason, most of the diffracted sound reaching each point in the front region of the sound radiated and diffracted from the speaker unit is re-radiated not to the front of the speaker cabinet but to the side or rear of the speaker cabinet. Therefore, peaks and dips due to the diffracted sound from the speaker unit do not easily appear in the frequency response at each listening point in front of the speaker unit. Further, in the present invention, a cavity communicating with the speaker unit mounting hole and having a small number of opposed parallel surfaces is formed inside the outer wall of the speaker cabinet. The outer surface of the rear region away from the speaker unit mounting hole has a non-similar shape to the inner surface facing the cavity inside the outer shell wall. Therefore, the inner surface of the outer shell wall facing the cavity is designed to have a shape that can effectively prevent the standing wave from being generated. What is the design of the inner surface of the outer shell wall facing the cavity? Independently, for example, the shape of the outer surface of the outer shell wall can be designed in consideration of the ease of placement and stability when placing the speaker cabinet on the floor, the aesthetic appearance, and the like.

It is a side view of the speaker which is one Embodiment of this invention. It is a longitudinal cross-sectional view of the same speaker. It is the figure which looked at the same speaker from arrow A direction. It is the figure which looked at the same speaker from arrow B direction. It is a figure which shows the frequency response measured for verification of the effect of the speaker. It is a figure which shows the structural example of the conventional speaker. It is a longitudinal cross-sectional view of the same speaker.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a right side view of a speaker 1 according to an embodiment of the present invention. FIG. 2 is a longitudinal sectional view of the speaker 1 of FIG. FIG. 3 is a view of the speaker 1 of FIG. FIG. 4 is a view of the speaker 1 of FIG. The speaker 1 includes a speaker unit 10 that serves as a sound generation source and a speaker cabinet 11 that serves as a casing that holds the speaker unit 10. The speaker cabinet 11 of the speaker 1 has a front end in a hollow rectangular parallelepiped having dimensions of left and right width H (for example, H = 65 mm), vertical width W (for example, W = 65 mm), and front and rear width L (for example, L = 90 mm). It has an external shape in which a part of the side and rear end side is rounded.

  The speaker cabinet 11 has an outer shell wall 12 in which a speaker unit mounting hole 13 for mounting the speaker unit 10 is formed in the front portion and a cavity 14 communicating with the speaker unit mounting hole 13 is formed inside. ing. Here, the cavity 14 inside the outer shell wall 12 is a substantially egg-shaped cavity that is long along the axial direction of the speaker unit 10, and the inner surface of the outer shell wall 12 facing this cavity 14 reciprocates the reflected sound. There are almost no opposing parallel surfaces. Therefore, standing waves are unlikely to occur in the cavity 14.

  On the other hand, paying attention to the outer surface of the outer shell wall 12, the configuration is as follows. First, the speaker unit mounting hole 13 in the front portion of the outer shell wall 12 has a perfect circle shape. The speaker unit 10 is fitted into the speaker unit mounting hole 13 with the sound emitting surface facing outward. On the outer surface of the outer shell wall 12, the front region in the vicinity of the speaker unit mounting hole 13 has a substantially hemispherical shape, and is a curved portion 17 that retreats backward as the distance from the speaker unit mounting hole 13 increases. In the curved portion 17, the outer surface and the inner surface of the outer shell wall 12 are maintained at substantially equal intervals.

  On the outer surface of the outer shell wall 12, the outer surface of the rear region farther from the speaker unit mounting hole 13 than the front region (curved portion 17) has a shape similar to the inner surface facing the cavity 14 on the inner side of the outer shell wall 12. Has a shape with different curvature. More specifically, in the illustrated example, the outer surface of the outer shell wall 12 in the rear region has a rectangular tube shape (or a rectangular parallelepiped shape) surrounded by the flat portions 18, 19, 20, and 21. Here, the flat portions 18 and 19 of the outer shell wall 12 face in the left-right direction, and the flat portions 20 and 21 face in the vertical direction. The plane portions 18 and 19 are orthogonal to the plane portions 20 and 21. The distance between each of the flat surface portions 18, 19, 20, and 21 forming the outer surface of the outer shell wall 12 and the inner surface of the outer shell wall 12, that is, the thickness of the outer shell wall 12 is increased as it advances toward the rear end side. It has become.

  A constricted portion 22 is provided slightly in front of the rear end of the outer shell wall 12. The constricted portion 22 has a cylindrical shape having a diameter smaller than the widths H and W of the speaker cabinet 11 itself. The constricted portion 22 is provided with a groove 24 extending from the peripheral surface 23 of the constricted portion 22 to the vicinity of the center. Further, a hole 25 is provided in the vicinity of the intersection with the central axis of the speaker cabinet 11 on the substantially egg-shaped inner surface of the outer shell wall 12 (that is, a position corresponding to the tip of the egg). Communicate. A cable 26 forming an audio signal transmission path is inserted into the cavity 14 through the groove 24 and the hole 25 and connected to the speaker unit 10.

  The above is the details of the configuration of the present embodiment. According to this embodiment, the following effects can be obtained. First, in the present embodiment, the front area near the speaker unit mounting hole 13 on the outer surface of the outer shell wall 12 of the speaker cabinet 11 retreats backward as the distance from the speaker unit 10 increases. For this reason, most of the diffracted sound reaching each point in the front region is re-radiated not toward the front of the speaker cabinet 11 but toward the side or rear of the speaker cabinet 11. Therefore, peaks and dips due to the diffracted sound from the speaker unit 10 are less likely to appear in the frequency response at each listening point in front of the speaker unit 10.

  Secondly, in this embodiment, only the front region where the diffracted sound from the speaker unit 10 can reach on the outer surface of the outer shell wall 12 of the speaker cabinet 11 is used as a curved portion 17 to avoid the occurrence of adverse effects due to the diffracted sound. The rear region has a shape suitable for placing the speaker cabinet 11 on the floor. Therefore, it is possible to prevent the adverse effect that the diffracted sound from the speaker unit 10 has on the acoustic characteristics without impairing the ease and stability of the arrangement. The conventional egg-shaped speaker cabinet (FIGS. 6 and 7) described above has an egg shape as a whole, and has to be provided with legs for placement on the floor. A speaker having such a speaker cabinet has a problem that the acoustic characteristics are deteriorated because the vibration of the speaker unit vibrates the speaker cabinet supported by the legs. However, in the present embodiment, the outer shape of the speaker cabinet 11 has a flat portion, and the speaker cabinet 11 can be placed on the floor with the flat portion facing down. Therefore, according to the present embodiment, there is no need to provide the legs in the speaker cabinet for placement on the floor, and problems due to the provision of the legs can be avoided.

  Thirdly, in the present embodiment, a substantially egg-shaped cavity 14 is formed inside the outer shell wall 12 of the speaker cabinet 11, and the inner surface of the outer shell wall 12 facing this cavity 14 has an almost parallel surface. Not done. For this reason, much of the sound transmitted to the inner surface is not reflected back and forth, and standing waves are less likely to occur in the cavity 14 in the speaker cabinet 11.

  Fourthly, in this embodiment, a substantially egg-shaped cavity 14 is formed inside the outer shell wall 12 of the speaker cabinet 11, and on the other hand, a rear region away from the speaker unit mounting hole 13 in the outer shell wall 12. The outer surface (plane portions 18 to 21) has a non-similar shape to the inner surface facing the cavity 14 inside the outer shell wall 12. Therefore, the inner surface of the outer shell wall 12 facing the cavity 14 is designed to have a shape that can effectively prevent the standing wave from being generated, and the inner surface shape of the outer shell wall 12 facing the cavity 14 is designed. Independently of the above design, the shape of the outer surface of the outer shell wall 12 can be designed in consideration of, for example, ease of placement and stability when the speaker cabinet 11 is placed on the floor.

  Fifth, in the present embodiment, another hole 25 is provided on the opposite side of the speaker unit mounting hole 13 into which the speaker unit 10 is fitted in the outer shell wall 12. For this reason, in this speaker 1, a Helmholtz resonator having the hole 25 as a neck and the cavity 14 as a cavity is formed. Therefore, according to the present embodiment, it is possible to improve the reproduction capability in the low sound range.

  Here, the inventors of the present application performed the following verification in order to confirm the effect of the present embodiment. The inventors of the present application input a test sound signal to the speaker unit 10 of the speaker 1, measure the sound at a measurement point P 1 m away from the speaker unit 10, and the sound pressure ratio between the spectrum of the input signal and the spectrum of the measurement signal The frequency response R1 (dB), which is (logarithmic difference), was calculated. FIG. 5 is a diagram showing the frequency response R1. In this frequency response R1, the sound pressure ratio in a band of 300 Hz or higher is relatively flat. Thus, according to the present embodiment, it is proved that the deterioration of the acoustic characteristics due to the influence of the reflected wave at each point on the outer surface of the speaker cabinet 11 of the speaker 1 and the standing wave inside the speaker cabinet 11 is prevented.

  As mentioned above, although embodiment of this invention was described, various other embodiment can be considered to this invention. For example, it is as follows.

(1) In the above embodiment, another hole 25 is provided on the opposite side of the speaker unit mounting hole 13 into which the speaker unit 10 is fitted in the outer shell wall 12. However, the hole 25 may be provided in any one of the plane portions 18, 19, 20, and 21.

(2) Without providing the constricted portion 22, a hole reaching the hole 25 from the outer surface side of the outer shell wall 12 may be provided in the outer shell wall 12.

(3) In the above-described embodiment, the outer shell wall 12 is provided with the hole 25 that plays both the role of passing the cable 26 and the role of the neck of the Helmholtz resonator. However, a hole that penetrates the thick part of the rear region of the outer shell wall 12 and serves only as a neck of the Helmholtz resonator may be provided.

(4) In the above embodiment, the flat portions 18, 19, 20, and 21 are provided in the rear region of the outer surface of the outer shell wall 12. However, the rear region of the outer surface of the outer shell wall 12 does not necessarily have to be constituted by four flat portions. The rear region of the outer surface of the outer shell wall 12 may have a shape having only one flat portion, specifically a shape in which a flat portion is provided on a part of a cylindrical side surface.

(5) In the above embodiment, the rear end portion of the speaker cabinet 11 is a flat portion. For example, the speaker cabinet 11 can be placed on the floor with the rear end portion facing down. Or the aspect which provides a suction cup in the rear-end part of the speaker cabinet 11, and fixes the speaker cabinet 11 to a wall etc. with this suction cup is also considered. In such an aspect, the rear region of the outer shell wall 12 of the speaker cabinet 11 may have a cylindrical shape without a flat portion.

(6) In the above embodiment, the speaker cabinet 11 may be configured by combining a plurality of outer shell walls. Alternatively, instead of making the rear region of the outer shell wall 12 thick, a cavity may be provided in the rear region, and the sound absorbing material may be accommodated in the cavity.

DESCRIPTION OF SYMBOLS 1 ... Speaker, 10 ... Speaker unit, 11 ... Speaker cabinet, 12 ... Outer wall, 13 ... Speaker unit mounting hole, 25 ... Hole, 14 ... Cavity, 17 ... Curved part, 18, 19, 20, 21 ... Plane part , 22 ... a constricted portion, 23 ... a circumferential surface, 24 ... a groove.

Claims (4)

A speaker unit mounting hole for mounting the speaker unit is formed in the front portion, and has an outer shell wall formed in a cavity communicating with the speaker unit mounting hole and having a small number of opposed parallel surfaces.
The front region of the outer shell wall near the speaker unit mounting hole is retracted rearward as the outer surface of the outer shell wall moves away from the speaker unit mounting hole, and the outer surface of the outer shell wall is more than the front region. The outer surface of the rear area away from the speaker unit mounting hole has a rectangular tube shape,
A constricted portion is provided in front of the rear end of the outer shell wall, and the constricted portion is provided with a groove through which a cable for transmitting an audio signal to the speaker unit is inserted to the vicinity of the center of the rear end. A speaker cabinet, wherein the outer shell wall is provided with a hole through which the cable is inserted from the groove into the cavity . 2. The speaker cabinet according to claim 1, wherein a rear region of the outer shell wall becomes thicker toward a rear end side of the outer shell wall. The speaker cabinet according to claim 1, wherein the hole serves as a neck of a Helmholtz resonator. A speaker unit is mounted in the speaker unit mounting hole of the speaker cabinet according to any one of claims 1 to 3, wherein the cable is inserted into the hole and the groove and connected to the speaker unit. The speaker characterized by becoming.

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