Omnidirectional speaker

Abstract

This provides an omnidirectional speaker whose acoustic characteristics can be easily adjusted. [Solution] The omnidirectional speaker comprises a cylindrical enclosure formed by stacking multiple annular members, and a speaker unit attached to the upper opening of the enclosure, with its sound-emitting surface facing upwards and its back surface, opposite the sound-emitting surface, facing inwards towards the enclosure.

Description

Technical Field

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[0001] The present invention relates to an omnidirectional speaker.

Background Art

[0002] In Patent Document 1, a speaker is attached to one opening of a cylindrical housing, and a columnar member is attached to the other opening so as to form a cylindrical gap between the housing and the columnar member, thereby causing the cylindrical gap to function as a duct and the other opening to function as a port. A bass-reflex omnidirectional speaker is disclosed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] ​​​​​​​​​​​​

[0007] In the above embodiment, the inner circumferential surface of the enclosure may have irregularities formed by the inner edges of the plurality of annular members. This makes it possible to attenuate the reverberation sound inside the enclosure.

[0008] In the above embodiment, the inner circumference shape of the plurality of annular members may be a closed curve that is not a perfect circle. This makes it possible to suppress the concentration of reverberation sound in the center of the enclosure.

[0009] In the above embodiment, the inner circumferential shapes of the plurality of annular members are the same, and the plurality of annular members may be stacked with the rotation angles of adjacent annular members being different from each other. This makes it possible to form irregularities using the same inner circumferential shape.

[0010] In the above embodiment, the enclosure includes a hollow body portion and a bass reflex portion located below the body portion, with a columnar member positioned inside and forming a gap between the columnar member and the bass reflex portion. The inner circumferential surface of the body portion may have irregularities, while the inner circumferential surface of the bass reflex portion may not have irregularities. This makes it possible to provide a bass reflex portion. [Effects of the Invention]

[0011] According to the present invention, it becomes easier to adjust the acoustic characteristics of the enclosure. [Brief explanation of the drawing]

[0012] [Figure 1] This is a side view showing an example of an omnidirectional speaker. [Figure 2] This is a cross-sectional view showing an example of an omnidirectional speaker. [Figure 3] This is a plan view showing an example of an annular member. [Figure 4] This is a perspective view showing an example of an annular member. [Figure 5] This is a diagram illustrating the measurement of reverberation. [Figure 6] This figure shows an example of the measurement results in the example. [Figure 7] This figure shows an example of measurement results for reference. [Modes for carrying out the invention]

[0013] Embodiments of the present invention will be described below with reference to the drawings. In this specification and in each drawing, elements similar to those described above in relation to previously shown drawings will be denoted by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0014] Figure 1 is a front view showing an example of an omnidirectional speaker 1. Figure 2 is a cross-sectional view showing an example of an omnidirectional speaker 1, illustrating the cross-sectional structure when the enclosure 2 is cut lengthwise. In the figure, the Z1 direction indicates the upward direction, and the Z2 direction indicates the downward direction. Figures 3 and 4 are plan and perspective views showing examples of annular members 3, which are components of the enclosure 2.

[0015] The omnidirectional speaker 1 comprises a cylindrical enclosure 2 and a speaker unit 5 mounted on the upper opening 2a of the enclosure 2. The enclosure 2 is mounted on a base 8 and extends in the vertical direction.

[0016] The wiring for the speaker unit 5, although not shown in the diagram, is routed along the inner surface of the enclosure 2 and connected to terminals embedded in the side of the base 8 through a hole formed in the base 8. Alternatively, it may be routed to the outside through a gap 8a formed between the enclosure 2 and the base 8.

[0017] The speaker unit 5 is mounted so that its sound-emitting surface faces upward and its opposite rear surface faces downward; that is, the sound-emitting surface faces outward from the enclosure 2 and the rear surface faces inward from the enclosure 2. The sound-emitting surface is the surface of the diaphragm (cone) in the direction of sound radiation.

[0018] When sound is emitted from the sound radiation surface of the speaker unit 5, sound with a 180-degree different phase is emitted from its back surface. When there is no enclosure 2, particularly in the long wavelength and low frequency range, the sound from the sound radiation surface (necessary sound) and the sound from the back surface (unnecessary sound) cancel each other out or distort each other.

[0019] The enclosure 2 is provided to confine the sound emitted from the back surface of the speaker unit 5 within the enclosure 2 so as not to affect the necessary sound emitted from the sound radiation surface.

[0020] As shown in FIGS. 1 and 2, the enclosure 2 includes a hollow body portion 21, a baffle portion 22 located above the body portion 21 to which the speaker unit 5 is attached, and a bass reflex portion 23 located below the body portion 21 with a columnar member 6 disposed inside.

[0021] The enclosure 2 is formed by stacking a plurality of annular members 3, 4. The outer peripheral shape of the annular members 3, 4 is, for example, circular, and the enclosure 2 has an overall cylindrical outer shape.

[0022] The annular members 3, 4 are formed of, for example, laminated wood. Since laminated wood has relatively high strength, it is suitable as the material for the annular members 3, 4. However, the annular members 3, 4 are not limited to this, and may be formed of solid wood, metal, synthetic resin, or the like.

[0023] The annular members 3, 4 are stacked via a thin packing, for example, called a gap tape, to enhance the airtightness. However, the annular members 3, 4 are not limited to this, and may be joined via an adhesive.

[0024] By stacking the annular members 3, 4 via packing without using an adhesive, it becomes easy to change the number of the annular members 3, 4 in the body portion 21 or the bass reflex portion 23 later to adjust the acoustic characteristics.

[0025] Furthermore, even when replacing the speaker unit 5, it is not necessary to rebuild the entire unit. The baffle section 22 can be replaced along with the speaker unit 5, and the number of annular members 3 and 4 in the body section 21 or bass reflex section 23 can be changed as needed.

[0026] As shown in Figure 2, the baffle portion 22 of the enclosure 2 is located at the upper end of the enclosure 2, and its through-hole is the upper opening 2a of the enclosure 2. The speaker unit 5 is fitted snugly into the through-hole of the baffle portion 22.

[0027] A diffuser 7 is positioned above the baffle section 22. The diffuser 7 is supported by a support bracket 79 attached to the baffle section 22 so that it is positioned above the speaker unit 5.

[0028] The diffuser 7 diffuses the sound emitted upward from the speaker unit 5 radially in the horizontal direction by the lower diffusion surface 72. Preferably, the diffusion surface 72 is a curved surface that is convex outward so that the sound reflected horizontally has a slight spread in the vertical direction.

[0029] As shown in Figure 2, the body portion 21 of the enclosure 2 is formed by stacking multiple annular members 3. The body portion 21 occupies most of the enclosure 2.

[0030] The sound emitted from the rear of speaker unit 5 into enclosure 2 must be attenuated quickly and sufficiently. If it cannot be attenuated, the sound will eventually return to speaker unit 5 and affect the necessary sound emitted from the sound radiating surface.

[0031] Therefore, in this embodiment, by forming the annular member 3 and the body portion 21 as described below, it is possible to quickly and sufficiently attenuate the sound emitted into the enclosure 2.

[0032] As shown in Figures 3 and 4, the annular member 3 is a relatively short disc-shaped member in the vertical direction (thickness direction) with a through hole 3h formed therein. The annular member 3 has an outer peripheral surface 31, an inner peripheral surface 32 surrounding the through hole 3h, and a pair of upper and lower end faces 33.

[0033] Around the through-hole 3h, multiple insertion holes 3e are formed into which long screws for fixing are inserted. The long screws inserted into the insertion holes 3e of the multiple annular members 3 are connected between the baffle portion 22 and the base 8, and the entire enclosure 2 is fixed by tightening them with nuts.

[0034] The inner circumferential shape of the annular member 3, that is, the shape of the inner circumferential surface 32 or the through hole 3h when viewed in the axial direction, is a closed curve, not a perfect circle. In other words, the inner circumferential shape of the annular member 3 is not a perfect circle, but approximately circular.

[0035] If the inner circumference of the annular member 3 is a perfect circle, the resonant sound will concentrate at its center, making it difficult to attenuate. Therefore, in this embodiment, the inner circumference of the annular member 3 is made into an irregular shape that deviates from a perfect circle, allowing for rapid and sufficient attenuation by causing diffuse reflection of the sound on the inner surface 32.

[0036] Specifically, the inner circumference shape of the annular member 3 is approximately circular, such as an oval (elliptical, egg-shaped, oblong, or almond-shaped), teardrop-shaped, or spindle-shaped (lens-shaped, rugby ball-shaped, or lemon-shaped). In the illustrated example, the inner circumference shape of the annular member 3 is spindle-shaped.

[0037] Furthermore, the inner circumference of the annular member 3 does not have to be entirely curved; it may include straight lines in part, such as a rounded rectangle or a capsule shape. Also, the inner circumference of the annular member 3 does not have to be entirely convex outward; it may include in part, such as a wavy circle.

[0038] As shown in Figure 2, the inner circumferential surface of the body portion 21 of the enclosure 2 is not flat, but has irregularities formed by the inner edges of the multiple annular members 3. The inner edges of the annular members 3 are a part of the inner circumferential side, including the inner circumferential surface 32.

[0039] In other words, the inner circumferential surfaces 32 of adjacent annular members 3 that make up the body portion 21 are not aligned on the same plane, and their radial positions are different from each other, forming steps. As a result, the end faces 33 facing in the vertical direction are partially exposed.

[0040] More specifically, the inner circumferential shapes of the multiple annular members 3 that constitute the body portion 21 are the same, and by stacking the multiple annular members 3 so that the rotation angles of adjacent annular members 3 differ from each other, numerous irregularities are formed on the inner circumferential surface of the body portion 21.

[0041] By forming numerous irregularities on the inner surface of the body portion 21 in this way, sound can be diffusely reflected, suppressing the generation of resonant sounds, thus enabling rapid and sufficient attenuation of sound inside the enclosure 2.

[0042] Furthermore, by forming numerous irregularities on the inner surface of the body portion 21, it is possible to quickly and sufficiently attenuate the sound inside the enclosure 2 without providing sound-absorbing material on the inner surface of the body portion 21. Sound-absorbing material may be provided for further attenuation.

[0043] As shown in Figure 2, the bass reflex section 23 of the enclosure 2 is formed by stacking multiple annular members 4, and a cylindrical gap 4g is formed between it and the columnar member 6 arranged on the inside.

[0044] The cylindrical gap 4g formed between the annular member 4 and the columnar member 6 of the bass reflex section 23 functions as a duct, and the gap 8a formed between the lower end of the bass reflex section 23 and the base 8 functions as a bass reflex port.

[0045] The inner circumference of the annular member 4 is, for example, circular, and the columnar member 6 is, for example, cylindrical, and the gap 4g between the annular member 4 and the columnar member 6 is formed in a cylindrical shape.

[0046] Furthermore, the columnar member 6 is formed, for example, from a hollow cylindrical pipe, and electronic components connected to the speaker unit 5 are housed inside it. However, it is not limited to this, and the columnar member 6 may also be a solid cylinder.

[0047] The inner surface of the bass reflex section 23 of the enclosure 2 is flat and has no irregularities. That is, the inner surfaces 42 of the multiple annular members 4 that constitute the bass reflex section 23 are aligned on the same plane.

[0048] By forming irregularities on the inner surface of the body section 21 and not forming irregularities on the inner surface of the bass reflex section 23, an attenuation effect is obtained in the body section 21, while in the bass reflex section 23, it becomes possible to invert the phase of sounds in a specific long wavelength / low frequency range based on the design.

[0049] Figure 5 is a diagram illustrating the measurement of reverberation. The reverberation was measured by placing a speaker SP in the upper opening of enclosure EC with its sound-emitting surface facing inward from enclosure EC, and placing a microphone MC in the lower inside of enclosure EC.

[0050] Figure 6 shows an example of reverberation measurement results in the embodiment. The horizontal axis represents time, and the vertical axis represents sound pressure level. In the embodiment, the enclosure EC is made by stacking multiple annular members 3, as in the body part 21 of the above embodiment, and has irregularities on its inner surface.

[0051] Figure 7 shows an example of reverberation measurement results in a reference example. In this reference example, the enclosure EC was made of dried bamboo.

[0052] In the reference example, the reverberation is approximately 36.1% at 10 msec and approximately 20.0% at 20 msec, whereas in the embodiment, the reverberation is approximately 15.0% at 10 msec and approximately 7.7% at 20 msec, which is about half the value. This shows that rapid and sufficient attenuation is achieved in the embodiment.

[0053] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and various modifications are of course possible for those skilled in the art. [Explanation of symbols]

[0054] 1 Omnidirectional speaker, 2 Enclosure, 21 Body section, 22 Baffle section, 23 Bass reflex section, 2a Upper opening, 3 Annular member, 31 Outer surface, 32 Inner surface, 33 End face, 3e Insertion hole, 3h Through hole, 4 Annular member, 42 Inner surface, 4g Gap, 5 Speaker unit, 6 Columnar member, 7 Diffuser, 72 Diffusion surface, 79 Support bracket, 8 Base, 8a Gap

Claims

1. A cylindrical enclosure formed by stacking multiple annular members, A speaker unit is attached to the upper opening of the enclosure, with its sound-emitting surface facing upwards and its rear surface, opposite to the sound-emitting surface, facing inwards towards the enclosure. An omnidirectional speaker equipped with [specific feature].

2. The inner circumferential surface of the enclosure has irregularities formed by the inner edges of the plurality of annular members. The omnidirectional speaker according to claim 1.

3. The inner circumference shape of the aforementioned plurality of annular members is a closed curve, not a perfect circle. The omnidirectional speaker according to claim 1.

4. The inner circumference shapes of the plurality of annular members are the same shape. The plurality of annular members are stacked so that the rotation angles of adjacent annular members are different from each other. The omnidirectional speaker according to claim 3.

5. The aforementioned enclosure is A hollow body section, A bass reflex section is located below the body portion, with a columnar member positioned inside and forming a gap between it and the columnar member, Includes, The inner surface of the body portion has irregularities, while the inner surface of the bass reflex portion does not have irregularities. The omnidirectional speaker according to claim 1.

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