Speaker system and sound diffusion method

Abstract

To provide a diffuser capable of widening directivity without distorting sound even when applied to a full-range type speaker.SOLUTION: A diffuser 1 includes a first communication hole 11, a first annular control portion 10 surrounding the first communication hole 11 and having an annular inclined plate 12 inclined with respect to an axial direction of the first communication hole 11, a second communication hole 21 coaxial with the first communication hole 11, and a second communication hole 22 surrounding the second communication hole 21 and accommodating the first annular control portion 10 inside. It has a second annular control part 20 having an annular inclined plate 22 inclined to the axial direction of the second communication hole 21, and a third annular control part 30 having a plurality of third communication holes 31 opened and surrounding the second annular control part 20.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a speaker system and a method for diffusing sound. [Background technology]

[0002] A technology for widening the directivity of a speaker system is disclosed in Patent Document 1. In the technology disclosed in Patent Document 1, the sound from a speaker unit is collected and narrowed into a small hole, and a droplet-shaped diffuser installed in this hole diffuses the sound, thereby widening the directivity. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 3818959 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the technology disclosed in Patent Document 1, a grill with many holes is not provided around the holes for effectively constricting the sound. If such a technology is applied to a full-range speaker, air may be trapped in the space between the diffuser and the speaker unit, causing distortion of the speaker unit and resulting in distorted sound.

[0005] This invention has been made in consideration of the above circumstances, and aims to provide a technical means that can widen the directivity without distorting the sound even when applied to a full-range speaker. [Means for solving the problem]

[0006] The present invention provides a sound diffuser having a first communication hole, a first annular control part surrounding the first communication hole and having an annular inclined plate inclined with respect to the axial direction of the first communication hole, a second communication hole, a second annular control part surrounding the second communication hole and accommodating the first annular control part inside and having an annular inclined plate inclined with respect to the axial direction of the second communication hole, and a third annular control part having a plurality of third communication holes opening therein and surrounding the second annular control part. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a plan view showing the configuration of a diffuser which is one embodiment of a sound diffuser according to the present invention. [Figure 2] FIG. 2 is a cross-sectional view taken along line II' in FIG. [Figure 3] FIG. 10 is a diagram illustrating an application example of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0009] Figure 1 is a plan view showing the configuration of a diffuser 1, which is one embodiment of a sound diffuser according to the present invention. Figure 2 is a cross-sectional view taken along line II' in Figure 1. In Figure 2, a speaker unit 2 is shown together with the diffuser 1 to make it easier to understand how the diffuser 1 is used.

[0010] As shown in FIGS. 1 and 2, the diffuser 1 has a first annular control portion 10, a second annular control portion 20, a third annular control portion 30, and support portions 41 to 44.

[0011] The first annular control part 10 is a funnel-shaped member having a first communication hole 11 at its center and an annular inclined plate 12 surrounding the first communication hole 11 and inclined with respect to the axial direction of the first communication hole 11. When the diffuser 1 is attached to the speaker unit 2, the axis of the first communication hole 11 coincides with the central axis O of the speaker unit 2.

[0012] The second annular control part 20 is a funnel-shaped member having a second communicating hole 21 in the center that is coaxial with the first communicating hole 11, surrounding this second communicating hole 21 and housing the first annular control part 10 inside, and having an annular inclined plate 22 that is inclined with respect to the axial direction of the second communicating hole 21.

[0013] In the illustrated example, the inclined plate 12 of the first annular control unit 10 is connected to the inclined plate 22 of the second annular control unit 20 via four support plates 13 extending radially from the inclined plate 12 and is supported by the inclined plate 22.

[0014] In this embodiment, as shown in Figure 2, the cross-sectional area of ​​the space between the inclined plate 12 of the first annular control unit 10 and the inclined plate 22 of the second annular control unit 20 increases as the distance from the axis of the first communication hole 11 and the second communication hole 21, i.e., the central axis O of the speaker unit 2, increases.

[0015] In addition, in this embodiment, as shown in Figure 2, the thickness of the inclined plate 22 of the second annular control member 20 increases as it moves away from the axis of the first communication hole 11 and the second communication hole 21, i.e., the central axis O of the speaker unit 2.

[0016] The third annular control part 30 corresponds to a grill, has a plurality of third communication holes 31 opened therein, and surrounds the second annular control part 20. In the illustrated example, the third annular control part 30 is composed of a plurality of concentric crosspiece members 32 and a plurality of ribs 33 extending radially outward from the center of the diffuser 1, and the plurality of third communication holes 31 are substantially rectangular communication holes surrounded by the crosspiece members 32 and the ribs 33.

[0017] Support portions 41 to 44 are provided at four locations around the periphery of diffuser 1. Through holes 41a to 44a are formed in support portions 41 to 44. Screws are inserted into these through holes 41a to 44a and then screwed into female threaded holes provided in a baffle plate (not shown) to which speaker unit 2 is attached, thereby fixing diffuser 1 to speaker unit 2.

[0018] In this embodiment, the sound emitted from the speaker unit 2 travels through the first communication holes 11 of the first annular control part 10 of the diffuser 1, and is guided into the space between the inclined plate 12 of the first annular control part 10 and the inclined plate 22 of the second annular control part 20. As the sound travels through this space, its directivity is broadened and the sound is emitted outside the diffuser 1. In addition, the sound emitted from the speaker unit 2 is emitted outside the diffuser 1 through a plurality of third communication holes 31 provided in the third annular control part 30.

[0019] In this embodiment, instead of narrowing the sound as in the technology of Patent Document 1, the directivity is widened by propagating the sound along the surfaces of the inclined plates 12 and 22. Therefore, according to this embodiment, even when the diffuser 1 is applied to a full-range speaker, the directivity can be widened without generating sound distortion.

[0020] Furthermore, according to this embodiment, the cross-sectional area of ​​the space between the inclined plate 12 of the first annular control part 10 and the inclined plate 22 of the second annular control part 20 increases with increasing distance from the central axis O, making it easier for sound to pass through the space between the inclined plates 12 and 22, thereby increasing the effect of widening the directionality.

[0021] Furthermore, according to this embodiment, the thickness of the inclined plate 22 of the second annular control member 20 increases with increasing distance from the central axis O of the speaker unit 2, which provides the following effects. First, the inclined plate 22 is thin near the central axis O, so that the sound emitted from the speaker unit 2 can be easily guided into the space between the inclined plates 12 and 22. Furthermore, the inclined plate 22 is thick farther from the central axis O, so that the mechanical strength of the inclined plate 22 that supports the inclined plate 12 is high.

[0022] 3 is a diagram showing an application example of this embodiment. In this application example, a speaker unit 2 is disposed on the upper surface of a shelf that supports the keys of an electronic keyboard musical instrument 3 placed on a floor 4. The sound emitting surface of this speaker unit 2 faces downward, and a diffuser 1 covers the sound emitting surface of this speaker unit 2. When a performer U1 sitting in a seat in front of the electronic keyboard musical instrument 3 plays the electronic keyboard musical instrument 3, the speaker unit 1 emits sound downward in response to the performance. In this application example, a listener U2 standing at a distance behind the performer U1 listens to the keyboard performance of the performer U1.

[0023] In Figure 3, the sound heard by performer U1 is dominated by the sound emitted by speaker unit 2, reflected by floor 4, and then reaching performer U1. If diffuser 1 were not provided, the directivity of the sound reflected by floor 4 would be narrow, which would create the problem that peaks and dips would be more likely to appear in the frequency characteristics of the sound heard by performer U1 due to interference from structures (e.g., floor 4 and keyboard electronic musical instrument 3). In addition, listener U2, who is standing at a distance from speaker unit 2, would have difficulty receiving the high-frequency sounds, in particular, of the performance sounds emitted by speaker unit 2.

[0024] However, in this application example, the sound emitting surface of the speaker unit 2 is covered by the diffuser 1. Therefore, the sound emitted from the speaker unit 1 passes through the diffuser 1 and travels toward the floor 4 as sound S1 with wide directivity. The sound S1 is then reflected by the floor 4 and becomes sound S2 with wide directivity, which is then emitted into a spatial region that encompasses the entire body of the performer U1. This solves the above-mentioned problems.

[0025] The inventors of the present invention conducted experiments and confirmed that providing a diffuser 1 in front of the speaker unit 2 broadened the directionality of the sound emitted from the speaker unit 2. Specifically, they confirmed that the sound pressure in directions of ±90 degrees relative to the drive axis direction of the speaker unit 2 increased from -12 dB to 0 dB at 1 kHz and increased from -20 dB to -5 dB at 2 kHz. They also confirmed that the sound pressure in directions of ±45 degrees relative to the drive axis direction of the speaker unit 2 increased from -30 dB to -2 dB at 2 kHz and increased from -30 dB to -9 dB at 4 kHz. Furthermore, when the diffuser 1 was not provided, the frequency characteristics of the sound heard by the performer U1 exhibited a large dip at 3 kHz, but they confirmed that providing the diffuser 1 improved this large dip at 3 kHz. When diffuser 1 was not installed, a large dip occurred at 3 kHz in the frequency characteristics of the sound heard by listener U2, but it was confirmed that when diffuser 1 was installed, this large dip at 3 kHz was improved.

[0026] <Other embodiments> Although one embodiment of the present invention has been described above, other embodiments of the present invention are also possible, for example as follows.

[0027] (1) In the above embodiment, funnel-shaped inclined plates are used as the annular inclined plates 12 and 22, but inclined plates having a side surface shaped like a truncated cone may also be used.

[0028] (2) In the above embodiment, both inclined plates are inclined so that the cross-sectional area of ​​the space inside the inclined plate 12 of the first annular control unit 10 and the cross-sectional area of ​​the space inside the inclined plate 22 of the second annular control unit 20 increase as one moves in the sound emission direction of the speaker unit 2. However, instead of doing so, both inclined plates may be inclined so that the cross-sectional area of ​​the space inside the inclined plate 12 of the first annular control unit 10 and the cross-sectional area of ​​the space inside the inclined plate 22 of the second annular control unit 20 decrease as one moves in the sound emission direction of the speaker unit 2.

[0029] (3) In the above embodiment, two inclined plates, namely, the inclined plate 12 of the first annular control section 10 and the inclined plate 22 of the second annular control section 20, are provided in the diffuser 1, but more inclined plates may be provided in the diffuser 1.

[0030] (4) The thickness of the inclined plate 12 of the first annular control unit 10 may also increase in the direction of sound emission of the speaker unit 2. In this case, the thicker portions are supported by the support plate 13. This increases the mechanical strength of the first annular control unit 10 and the support plate 13.

[0031] (5) The degree of inclination of the inclined plate 22 of the second annular control unit 20 may be made larger than the degree of inclination of the inclined plate 12 of the first annular control unit 10 with respect to the sound emission direction toward the diffuser 1, i.e., the direction of the central axis O of the speaker unit 2. In this case, the cross-sectional area of ​​the space between the inclined plate 12 of the first annular control unit 10 and the inclined plate 22 of the second annular control unit 20 increases as the sound advances in the sound emission direction, making it easier for sound to pass through and increasing the effect of widening the directivity.

[0032] (6) The four support plates 13 that support the first annular control unit 10 are supported by the second annular control unit 20, but may be supported by the third annular control unit 30. In this case, the support plates 13 are supported by the crosspiece members 32 that constitute the third annular control unit 30, or the ribs 33, or both.

[0033] (7) In the above embodiment, the drive shaft of the speaker unit 2, the axis of the first communication hole 11, and the axis of the second communication hole 21 are coaxial. However, from the viewpoint of directivity control, they do not necessarily have to be coaxial. For example, the axis of the first communication hole 11 may be configured to be inclined from the drive shaft of the speaker unit 2, for example, as shown in FIG. 3, the axis of the first communication hole 11 may be configured to be inclined toward the legs of the performer U1. This is expected to further widen the directivity.

[0034] (8) In the above embodiment, the present invention was implemented as a diffuser 1 in which the first annular control unit 10, the second annular control unit 20, and the third annular control unit 30 are integrated. However, the embodiment of the present invention is not limited to this. The present invention may also be implemented as a sound diffusion method in which the following components are arranged in front of the sound-emitting surface of a speaker unit: a first annular control unit that has a first communication hole, a first annular control unit that surrounds the first communication hole and has an annular inclined plate that is inclined with respect to the axial direction of the first communication hole; a second annular control unit that surrounds the second communication hole and houses the first annular control unit inside and has an annular inclined plate that is inclined with respect to the axial direction of the second communication hole; and a third annular control unit that has a plurality of third communication holes and surrounds the second annular control unit, and the three components are arranged in front of the sound-emitting surface of the speaker unit to widen the directionality of sound emitted from the speaker unit. [Explanation of symbols]

[0035] 1...diffuser, 10...first annular control portion, 11...first communication hole, 12, 22...inclined plates, 13...support plate, 20...second annular control portion, 21...second communication hole, 30...third annular control portion, 31...third communication hole, 32...crosspiece member, 33...rib, 41-44...support portion, 41a-44a...through holes, 2...speaker unit, 3...keyboard electronic musical instrument, 4...floor, U1...performer, U2...listener.

Claims

1. A cone-type speaker unit; a diffuser disposed in front of the sound emitting surface of the cone-type speaker unit, the diffuser has an annular control portion that surrounds a central axis of the cone-type speaker unit and has an annular inclined plate that is inclined with respect to an axial direction of the central axis, the distance between the cone-type speaker unit and the inclined plate increases with increasing distance from the central axis; Speaker system.

2. a diffuser that surrounds a central axis of a cone-type speaker unit and has an annular control portion having an annular inclined plate inclined with respect to the axial direction of the central axis, the distance between the cone-type speaker unit and the inclined plate increasing with increasing distance from the central axis, and that is disposed in front of the sound emitting surface of the cone-type speaker unit to widen the directionality of the sound emitted from the cone-type speaker unit; How sound is diffused.

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