Omnidirectional speaker

Abstract

To provide an omnidirectional speaker that allows easy adjustment of the acoustic characteristics of an enclosure. [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 upward and its back surface opposite the sound emitting surface facing inside the enclosure.

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a bass-reflex omnidirectional speaker in which 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 speaker and the housing, allowing the cylindrical gap to function as a duct and the other opening to function as a port. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4870242 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, the acoustic characteristics of an enclosure depend greatly on its size, but once a speaker is completed as a product, it cannot be easily adjusted thereafter.

[0005] The present invention has been made in view of the above-mentioned problems, and a main object of the present invention is to provide an omnidirectional speaker that allows easy adjustment of the acoustic characteristics of the enclosure. [Means for solving the problem]

[0006] To solve the above problems, one aspect of the present invention provides an omnidirectional speaker that includes a cylindrical enclosure formed by stacking a plurality of annular members, and a speaker unit attached to an upper opening of the enclosure, with a sound emitting surface facing upward and a rear surface opposite the sound emitting surface facing inward of the enclosure, making it easy to adjust the acoustic characteristics of the enclosure.

[0007] In the above aspect, the inner peripheral surface of the enclosure may have irregularities formed by inner edge portions of the plurality of annular members, thereby making it possible to attenuate reverberation within the enclosure.

[0008] In the above aspect, the inner peripheral shape of the plurality of annular members may be a closed curve rather than a perfect circle. This makes it possible to prevent reverberation within the enclosure from concentrating at the center.

[0009] In the above aspect, the inner peripheral shapes of the plurality of annular members may be the same, and the plurality of annular members may be stacked such that the rotation angles of adjacent annular members are different from each other. This makes it possible to form concave and convex shapes using the same inner peripheral shape.

[0010] In the above aspect, the enclosure includes a hollow body portion and a bass reflex portion located below the body portion, with a pillar-shaped member disposed inside and forming a gap between the pillar-shaped member and the bass reflex portion, and the inner circumferential surface of the body portion may have an uneven surface, while the inner circumferential surface of the bass reflex portion may not have an uneven surface. This makes it possible to provide a bass reflex portion. [Effects of the Invention]

[0011] The present invention makes it easy to adjust the acoustic characteristics of the enclosure. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a side view showing an example of an omnidirectional speaker. [Figure 2] FIG. 1 is a cross-sectional view showing an example of an omnidirectional speaker. [Figure 3] FIG. 10 is a plan view showing an example of an annular member. [Figure 4] FIG. 10 is a perspective view illustrating an example of an annular member. [Figure 5] FIG. 10 is a diagram for explaining measurement of reverberation sound. [Figure 6] FIG. 10 is a diagram showing an example of measurement results in an example. [Figure 7] FIG. 10 is a diagram showing an example of measurement results of a reference example. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this specification and the drawings, elements similar to those described above with reference to the previous drawings will be designated by the same reference numerals, and detailed descriptions thereof may be omitted as appropriate.

[0014] FIG. 1 is a front view showing an example of an omnidirectional speaker 1. FIG. 2 is a cross-sectional view showing an example of the omnidirectional speaker 1, showing the cross-sectional structure when the enclosure 2 is cut vertically. In the figure, the Z1 direction indicates the upward direction, and the Z2 direction indicates the downward direction. FIG. 3 and FIG. 4 are a plan view and a perspective view showing an example of an annular member 3 that is a component of the enclosure 2.

[0015] The omnidirectional speaker 1 includes a cylindrical enclosure 2 and a speaker unit 5 attached to an upper opening 2a of the enclosure 2. The enclosure 2 is placed on a base 8 and extends in the vertical direction.

[0016] Although not shown, the wiring of the speaker unit 5 is arranged along the inner peripheral surface of the enclosure 2 and passes through a hole formed in the base 8 to be connected to a terminal embedded in the side surface of the base 8. Alternatively, the wiring may be taken out to the outside through a gap 8a formed between the enclosure 2 and the base 8.

[0017] The speaker unit 5 is attached so that its sound emitting surface faces upward and its opposite back surface faces downward, i.e., so that its sound emitting surface faces the outside of the enclosure 2 and its back surface faces the inside of the enclosure 2. The sound emitting surface is the surface in the radiating direction of the diaphragm (cone).

[0018] When sound is emitted from the sound emitting surface of the speaker unit 5, sound with a phase difference of 180 degrees is emitted from the rear surface. Without the enclosure 2, the sound from the sound emitting surface (desired sound) and the sound from the rear surface (unwanted sound) cancel each other out or become distorted, especially in the long wavelength and low frequency ranges.

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

[0020] As shown in Figures 1 and 2, the enclosure 2 comprises a hollow body portion 21, a baffle portion 22 located above the body portion 21 and to which the speaker unit 5 is attached, and a bass reflex portion 23 located below the body portion 21 and inside which a pillar-shaped member 6 is arranged.

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

[0022] The annular members 3 and 4 are formed, for example, from laminated wood. Laminated wood has relatively high strength and is therefore suitable as a material for the annular members 3 and 4. However, the annular members 3 and 4 may also be formed from solid wood, metal, synthetic resin, or the like.

[0023] The annular members 3 and 4 are stacked together with a thin packing called gap tape interposed therebetween to enhance the airtightness, but the annular members 3 and 4 may also be joined together with an adhesive.

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

[0025] Furthermore, even when the speaker unit 5 is replaced, it is not necessary to remake everything; it is possible to simply replace the baffle part 22 along with the speaker unit 5 and change the number of annular members 3, 4 in the body part 21 or bass reflex part 23 as necessary.

[0026] 2, the baffle portion 22 of the enclosure 2 is located at the upper end of the enclosure 2, and the through-hole thereof serves as the upper opening 2a of the enclosure 2. The speaker unit 5 is fitted tightly into the through-hole of the baffle portion 22.

[0027] The diffuser 7 is disposed above the baffle portion 22. The diffuser 7 is supported by a support bracket 79 attached to the baffle portion 22 so as to be 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. The diffusion surface 72 is preferably a curved surface that is convex outward so that the sound reflected horizontally has some spread in the vertical direction.

[0029] 2, the body portion 21 of the enclosure 2 is formed by stacking a plurality of annular members 3. The body portion 21 occupies most of the enclosure 2.

[0030] The sound emitted into the enclosure 2 from the rear of the speaker unit 5 needs to be attenuated quickly and sufficiently. If it cannot be attenuated, the sound will eventually return to the speaker unit 5 and affect the necessary sound emitted from the sound emitting 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] 3 and 4, the annular member 3 is a disk-shaped member that is relatively short in the vertical direction (thickness direction) and has a through hole 3h formed therein. The annular member 3 has an outer peripheral surface 31, an inner peripheral surface 32 that surrounds the through hole 3h, and a pair of upper and lower end faces 33.

[0033] A plurality of insertion holes 3e into which long screws for fixing are inserted are formed around the through hole 3h. The long screws inserted into the insertion holes 3e of the plurality of annular members 3 are connected between the baffle portion 22 and the base 8, and are then tightened with nuts to fix the entire enclosure 2 in place.

[0034] The inner peripheral shape of the annular member 3, i.e., the shape of the inner peripheral surface 32 or the through hole 3h when viewed in the axial direction, is a closed curve that is not a perfect circle. That is, the inner peripheral shape of the annular member 3 is not a perfect circle but an approximately circular shape.

[0035] If the inner peripheral shape of the annular member 3 were a perfect circle, the resonant sound would concentrate at the center, making it difficult to attenuate. Therefore, in this embodiment, the inner peripheral shape of the annular member 3 is made distorted and deviates from a perfect circle, and the sound is diffusely reflected by the inner peripheral surface 32, allowing for quick and sufficient attenuation.

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

[0037] The inner peripheral shape of the annular member 3 does not need to be entirely curved, and may include some straight lines, such as a rounded rectangle or a capsule shape. The inner peripheral shape of the annular member 3 does not need to be entirely convex outward, and may be partially convex inward, such as a wavy circle.

[0038] 2, the inner peripheral surface of the body portion 21 of the enclosure 2 is not flat, but has irregularities formed by the inner edge portions of the multiple annular members 3. The inner edge portions of the annular members 3 are a part of the inner peripheral side including the inner peripheral surface 32.

[0039] That is, the inner circumferential surfaces 32 of adjacent annular members 3 of the multiple annular members 3 that make up the body portion 21 are not aligned on the same plane, but are positioned at different radial positions, forming a step, which results in the end faces 33 facing in the vertical direction being partially exposed.

[0040] In detail, the inner peripheral shapes of the multiple annular members 3 that make up the body portion 21 have the same shape, and by stacking the multiple annular members 3 so that the rotation angles of adjacent annular members 3 are different from each other, a large number of irregularities are formed on the inner peripheral surface of the body portion 21.

[0041] By forming a large number of irregularities on the inner peripheral surface of the body portion 21 in this way, sound can be diffusely reflected and the generation of resonance sound can be suppressed, making it possible to quickly and sufficiently attenuate sound inside the enclosure 2.

[0042] Furthermore, by forming a large number of projections and recesses on the inner peripheral surface of the body portion 21, it becomes possible to quickly and sufficiently attenuate sound inside the enclosure 2 without providing a sound-absorbing member on the inner peripheral surface of the body portion 21. Note that a sound-absorbing material may be provided for further attenuation.

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

[0044] A 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 a 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 peripheral shape of the annular member 4 is, for example, circular, 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 pillar-shaped member 6 is formed, for example, from a hollow cylindrical pipe, and houses electronic components connected to the speaker unit 5 inside thereof. However, the pillar-shaped member 6 is not limited to this, and may also be a solid cylinder.

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

[0048] By forming unevenness on the inner peripheral surface of the body portion 21 and not forming unevenness on the inner peripheral surface of the bass reflex portion 23, it is possible to obtain a damping effect in the body portion 21, while inverting the phase of sounds in a specific long wavelength and low frequency range based on the design in the bass reflex portion 23.

[0049] 5 is a diagram for explaining the measurement of reverberation sound. The reverberation sound was measured by placing a speaker SP at the upper opening of the enclosure EC with its sound emitting surface facing the inside of the enclosure EC, and placing a microphone MC at the bottom inside the enclosure EC.

[0050] 6 is a diagram showing an example of measurement results of reverberation sound in an example. The horizontal axis represents time, and the vertical axis represents sound pressure level. In the example, the enclosure EC was made by stacking multiple annular members 3, like the body portion 21 of the above embodiment, and had an uneven inner surface.

[0051] 7 is a diagram showing an example of measurement results of reverberation sound in a reference example. In the reference example, the enclosure EC was made of dry-distilled bamboo.

[0052] In the reference example, the reverberation sound is approximately 36.1% at 10 ms and approximately 20.0% at 20 ms, whereas in the working example, the reverberation sound is approximately 15.0% at 10 ms and approximately 7.7% at 20 ms, which is about half the figure, and it can be seen that the working example achieves rapid and sufficient attenuation.

[0053] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made by those skilled in the art. [Explanation of symbols]

[0054] 1 omnidirectional speaker, 2 enclosure, 21 body part, 22 baffle part, 23 bass reflex part, 2a upper opening, 3 annular member, 31 outer peripheral surface, 32 inner peripheral surface, 33 end face, 3e insertion hole, 3h through hole, 4 annular member, 42 inner peripheral 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 a plurality of annular members; a speaker unit attached to an upper opening of the enclosure, with a sound emitting surface facing upward and a rear surface opposite to the sound emitting surface facing the inside of the enclosure; Equipped with The inner peripheral surface of the enclosure has irregularities in which a plurality of recesses and a plurality of protrusions are alternately arranged in the axial direction, the irregularities being formed by the radial positions of inner edge portions of adjacent annular members among the plurality of annular members being different from each other. Omnidirectional speaker.

2. a cylindrical enclosure formed by stacking a plurality of annular members; a speaker unit attached to an upper opening of the enclosure, with a sound emitting surface facing upward and a rear surface opposite to the sound emitting surface facing the inside of the enclosure; Equipped with the inner circumferential shapes of the plurality of annular members are closed curves that are not perfect circles, The inner circumferential shapes of the plurality of annular members have the same shape, The plurality of annular members are stacked with adjacent annular members having different rotation angles. Omnidirectional speaker.

3. The enclosure comprises: A hollow body portion; a bass reflex section located below the body section, with a pillar-shaped member disposed inside the bass reflex section, forming a gap between the pillar-shaped member and the bass reflex section; Including, The inner peripheral surface of the body portion has irregularities, and the inner peripheral surface of the bass reflex portion does not have irregularities.

2. The omnidirectional speaker according to claim 1.

4. The enclosure comprises: A hollow body portion; a bass reflex section located below the body section, with a pillar-shaped member disposed inside the bass reflex section, forming a gap between the pillar-shaped member and the bass reflex section; Including, The inner peripheral surface of the body portion has irregularities, and the inner peripheral surface of the bass reflex portion does not have irregularities.

3. The omnidirectional speaker according to claim 2.

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