Diffuser for sound and diffusion method

Abstract

To provide a diffuser capable of widening directivity without distorting sound even if applied to a full range type speaker.SOLUTION: A diffuser 1 which is a diffusion instrument comprises: a first communication hole 11; a first annular control section 10 enclosing the first communication hole 11 and including an annular inclined plate 12 which is inclined in an axial direction of the first communication hole 11; a second communication hole 21 which is coaxial with the first communication hole 11; a second annular control section 20 enclosing the second communication hole 21, accommodating the first annular control section 10 inside and including an annular inclined plate 22 which is inclined in an axial direction of the second communication hole 21; and a third annular control section 30 in which a plurality of third communication holes 31 are opened and which encloses the second annular control section 20.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a sound diffuser and a diffusion method for expanding the directivity of a speaker system.

Background Art

[0002] As a technique for expanding the directivity of a speaker system, there is one disclosed in Patent Document 1. In the technique disclosed in this Patent Document 1, sound from a speaker unit is collected into small holes and narrowed down, and a droplet-shaped diffuser provided in these holes diffuses the sound to expand the directivity.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the technique disclosed in Patent Document 1, in order to effectively narrow down the sound, a grill with many holes is not provided around the hole for narrowing down. When such a technique is applied to a full-range speaker, air may be confined in the space between the diffuser and the speaker unit, and the sound may be distorted due to distortion of the speaker unit.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a technical means capable of expanding the directivity without distorting the sound even when applied to a full-range speaker.

Means for Solving the Problems

[0006] The present invention provides a sound diffuser having a first communication hole, a first annular control portion 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 portion surrounding the second communication hole, accommodating the first annular control portion inside, and having an annular inclined plate inclined with respect to the axial direction of the second communication hole, and a third annular control portion in which a plurality of third communication holes are opened and which surrounds the second annular control portion.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

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

[0009] FIG. 1 is a plan view showing the configuration of a diffuser 1 which is an embodiment of the sound diffuser according to the present invention. FIG. 2 is a sectional view taken along line I-I' of FIG. 1. In FIG. 2, a speaker unit 2 is shown together with the diffuser 1 in order to clearly show the usage state of the diffuser 1.

[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, and a first communication hole 11 is formed in the center thereof. An annular inclined plate 12 that surrounds the first communication hole 11 and is inclined with respect to the axial direction of the first communication hole 11 is provided. In a state where 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, and a second communication hole 21 coaxial with the first communication hole 11 is formed in the center thereof. An annular inclined plate 22 that surrounds the second communication hole 21 and houses the first annular control part 10 inside and is inclined with respect to the axial direction of the second communication hole 21 is provided.

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

[0014] And in the present embodiment, as shown in FIG. 2, as the axes of the first communication hole 11 and the second communication hole 21, that is, as the distance from the central axis O of the speaker unit 2 increases, 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 expands.

[0015] Also, in the present embodiment, as shown in FIG. 2, as the axes of the first communication hole 11 and the second communication hole 21, that is, as the distance from the central axis O of the speaker unit 2 increases, the thickness of the inclined plate 22 of the second annular control member 20 increases.

[0016] The third annular control part 30 corresponds to a grill, and a plurality of third communication holes 31 are formed and surround the second annular control part 20. In the illustrated example, the third annular control part 30 is composed of a plurality of concentric bar members 32 and a plurality of ribs 33 that radially extend in a direction from the center of the diffuser 1 toward the outside, and the plurality of third communication holes 31 are substantially rectangular communication holes surrounded by the bar members 32 and the ribs 33.

[0017] The support portions 41 to 44 are provided at four locations around the diffuser 1. Through holes 41a to 44a are formed in the support portions 41 to 44. By inserting a screw through the through holes 41a to 44a and screwing it into a female screw hole provided in a baffle plate (not shown) to which the speaker unit 2 is attached, the diffuser 1 is fixed to the speaker unit 2.

[0018] In the present embodiment, the sound emitted from the speaker unit 2 travels through the first communication hole 11 of the first annular control portion 10 of the diffuser 1. On the other hand, it is guided to the space between the inclined plate 12 of the first annular control portion 10 and the inclined plate 22 of the second annular control portion 20, and by traveling through this space, the directivity is widened and the sound is emitted to the outside of the diffuser 1. Further, the sound emitted from the speaker unit 2 is emitted to the outside of the diffuser 1 through a plurality of third communication holes 31 provided in the third annular control portion 30.

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

[0020] Further, according to the present embodiment, as the distance from the central axis O increases, the cross-sectional area of the space between the inclined plate 12 of the first annular control portion 10 and the inclined plate 22 of the second annular control portion 20 widens. Therefore, it is easier for the sound to pass through the space between the inclined plates 12 and 22, and the effect of widening the directivity increases.

[0021] Also, according to the present embodiment, in the second annular control member 20, as the distance from the central axis O of the speaker unit 2 increases, the thickness of the inclined plate 22 increases, so the following effects can be obtained. First, near the central axis O, since the inclined plate 22 is thin, the sound emitted from the speaker unit 2 can be easily guided into the space between the inclined plates 12 and 22. Also, at a position far from the central axis O, since the inclined plate 22 is thick, the mechanical strength of the inclined plate 22 that supports the inclined plate 12 is high.

[0022] FIG. 3 is a diagram showing an application example of the present embodiment. In this application example, in a keyboard electronic musical instrument 3 installed on the floor 4, a speaker unit 2 is arranged on the upper surface of a shelf plate that supports keys. This speaker unit 2 has its sound emission surface facing downward, and the diffuser 1 covers the sound emission surface of this speaker unit 2. When a performer U1 sitting on a seat in front of the keyboard electronic musical instrument 3 plays the keyboard electronic musical instrument 3, the speaker unit 1 emits sound downward in response to this performance. Also, in this application example, a listener U2 standing at a distant position behind the performer U1 is listening to the keyboard performance of the performer U1.

[0023] In FIG. 3, the sound that the performer U1 hears is mainly the sound emitted by the speaker unit 2 and reflected by the floor 4 and reaching the performer U1. If the diffuser 1 is not provided, since the directivity of the sound reflected by the floor 4 is narrow, there is a problem that peak dips due to interference of structures (for example, the floor 4 and the keyboard electronic musical instrument 3) easily appear in the frequency characteristics of the sound that the performer U1 hears. Also, there is a problem that it is difficult for the listener U2 standing at a position far from the speaker unit 2 to receive particularly high-frequency sounds among the performance sounds emitted by the speaker unit 2.

[0024] However, in this application example, the sound emission surface of the speaker unit 2 is covered by the diffuser 1. For this reason, the sound emitted from the speaker unit 1 passes through the diffuser 1 and becomes the sound S1 with a widened directivity, heading towards the floor 4. Then, the sound S1 is reflected by the floor 4 and becomes the sound S2 with a widened directivity, which is emitted into the space area encompassing the entire body of the performer U1. Therefore, the above-mentioned various problems are solved.

[0025] When the inventor of the present application conducted experiments, it was confirmed that by providing the diffuser 1 in front of the speaker unit 2, the directivity of the sound emitted from the speaker unit 2 spreads. Specifically, it was confirmed that the sound pressure in the directions ±90 degrees with respect to the driving axis direction of the speaker unit 2 increased from -12 dB to 0 dB at 1 kHz and from -20 dB to -5 dB at 2 kHz. Also, it was confirmed that the sound pressure in the directions ±45 degrees with respect to the driving axis direction of the speaker unit 2 increased from -30 dB to -2 dB at 2 kHz and from -30 dB to -9 dB at 4 kHz. Further, in the frequency characteristics of the sound heard by the performer U1 when the diffuser 1 was not provided, a large dip occurred at 3 kHz, but it was confirmed that this large dip at 3 kHz was improved when the diffuser 1 was provided. Also, in the frequency characteristics of the sound heard by the listener U2 when the diffuser 1 was not provided, a large dip occurred at 3 kHz, but it was confirmed that this large dip at 3 kHz was improved when the diffuser 1 was provided.

[0026] <Other Embodiments> As described above, one embodiment of this invention has been explained, but other embodiments are also conceivable for this invention. For example, as follows.

[0027] (1) In the above embodiment, as the annular inclined plates 12 and 22, a funnel-shaped inclined plate was adopted, but an inclined plate having the side surface shape of a frustum of a cone may be adopted.

[0028] (2) In the above embodiment, as going in the sound emission direction of the speaker unit 2, the inclined plates of the first annular control unit 10 and the second annular control unit 20 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. However, instead of doing so, as going in the sound emission direction of the speaker unit 2, the 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.

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

[0030] (4) The first annular control unit 10 may also be configured such that the thickness of the inclined plate 12 increases as going in the sound emission direction of the speaker unit 2. In this case, the thick portion is supported by the support plate 13. By doing so, the mechanical strength of the first annular control unit 10 and the support plate 13 increases.

[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 to the diffuser 1, that is, the direction of the central axis O of the speaker unit 2. In this case, as going in the sound emission direction, 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, so the sound easily passes through and the effect of widening the directivity increases.

[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 plate 13 is supported by the cross member 32 that constitutes the third annular control unit 30, or the rib 33, or both of them.

[0033] (7) In the above-described 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 were coaxial. However, from the perspective of directivity control, they do not necessarily have to be coaxial. For example, a configuration in which the axis of the first communication hole 11 is inclined from the drive shaft of the speaker unit 2, for example, in FIG. 3, a configuration in which the axis of the first communication hole 11 is inclined in the direction of the leg of the performer U1 may be adopted. By doing so, it is expected that the directivity will be more spread.

[0034] (8) In the above-described embodiment, the present invention was implemented as the diffuser 1 in which the first annular control unit 10, the second annular control unit 20, and the third annular control unit 30 were integrated. However, the embodiments of the present invention are not limited to this. The present invention can also be implemented as a sound diffusion method for expanding the directivity of the sound emitted from the speaker unit by arranging a first communication hole, a first annular control unit having an annular inclined plate surrounding the first communication hole and inclined with respect to the axial direction of the first communication hole, a second communication hole, a second annular control unit surrounding the second communication hole and accommodating the first annular control unit inside and having an annular inclined plate inclined with respect to the axial direction of the second communication hole, and a third annular control unit having a plurality of third communication holes opening and surrounding the second annular control unit on the front surface of the sound emission surface of the speaker unit.

Explanation of Reference Numerals

[0035] 1... Diffuser, 10... First annular control unit, 11... First communication hole, 12, 22... Inclined plate, 13... Support plate, 20... Second annular control unit, 21... Second communication hole, 30... Third annular control unit, 31... Third communication hole, 32... Cross member, 33... Rib, 41 - 44... Support part, 41a - 44a... Through hole, 2... Speaker unit, 3... Keyboard electronic musical instrument, 4... Floor, U1... Performer, U2... Listener.

Claims

1. a first communication hole; and a first annular control portion surrounding the first communication hole and having an annular inclined plate inclined with respect to an axial direction of the first communication hole; a second communication hole; a second annular control portion surrounding the second communication hole and accommodating the first annular control portion therein, the second annular control portion having an annular inclined plate inclined with respect to an axial direction of the second communication hole; a third annular control portion having a plurality of third communication holes opening therein and surrounding the second annular control portion; having the distance between the speaker unit and the inclined plate of the second annular control portion increases with increasing distance from the axis of the second communication hole; Sound diffuser.

2. 2. The diffuser of claim 1, wherein said second aperture is coaxial with said first aperture.

3. 3. The diffuser according to claim 1, wherein a cross-sectional area of ​​a space between the inclined plate of the first annular control portion and the inclined plate of the second annular control portion increases with increasing distance from the axis of the second communication hole.

4. 4. The diffuser according to claim 1, wherein the inclined plate of the second annular control portion has a thickness that increases with increasing distance from the axis of the second communication hole.

5. 5. The diffuser according to claim 1, wherein the inclined plate of the first annular control portion has a thickness that increases with increasing distance from the axis of the first communication hole.

6. A diffuser as described in any one of claims 1 to 5, wherein the degree of inclination of the inclined plate of the second annular control section is greater than the degree of inclination of the inclined plate of the first annular control section relative to the sound emission direction to the diffuser.

7. 2. The diffuser of claim 1, wherein the first annular control portion is connected to the second annular control portion via at least one support plate extending radially between an inclined plate of the first annular control portion and an inclined plate of the second annular control portion.

8. 2. The diffuser of claim 1, wherein the third annular control portion forms a speaker grille.

9. A diffuser as described in claim 8, wherein the third communication hole of the third annular control portion is positioned so as not to overlap with the inclined plate of the second annular control portion when observed from the axial direction of the second communication hole.

10. The diffuser described in claim 1, wherein the multiple third communication holes arranged radially in the third annular control portion relative to the axial direction of the second communication hole include a fourth communication hole and a fifth communication hole located closer to the second annular control portion than the fourth communication hole and having a shorter radial length than the fourth communication hole.

11. a first communication hole; and a first annular control portion surrounding the first communication hole and having an annular inclined plate inclined with respect to an axial direction of the first communication hole; a second communication hole; a second annular control portion surrounding the second communication hole and accommodating the first annular control portion therein, the second annular control portion having an annular inclined plate inclined with respect to an axial direction of the second communication hole; a third annular control portion having a plurality of third communication holes opening therein and surrounding the second annular control portion; having the distance between the speaker unit and the inclined plate of the second annular control portion increases with increasing distance from the axis of the second communication hole; The diffuser is placed in front of the sound emitting surface of the speaker unit. Expanding the directionality of sound emitted from the speaker unit How sound is spread.

Images