JPH04216300A - Nondirectional loudspeaker system - Google Patents

Abstract

PURPOSE:To present the nondirectional loudspeaker system improving the fre quency characteristic. CONSTITUTION:Two dome loudspeakers 1 and 1 to be driven in a common mode are faced each other, and horn forming faces 1b and 1b are provided around respective diaphragms 1a and 1a. Woofers 2 linked to the dome loudspeakers 1 are arranged so as to block the upper opening part of a cylindrical enclosure 3 and at the intermediate part of the cylindrical enclosure 3, woofer 7 are further arranged so as to be driven in the common mode while being faced each other. Then, on the lower side face of the cylindrical enclosure 3, plural acoustic wave radiation windows 4 are provided.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an omnidirectional speaker system, and more particularly to an omnidirectional speaker system that has improved frequency characteristics and reproduces a sound field that is consistent with ordinary speaker systems.

0002

2. Description of the Related Art Musical instruments generally have the property of emitting sound in all directions, that is, are omnidirectional, and conventionally omnidirectional speaker systems have been used to reproduce the sound field at performance venues. An example of such an omnidirectional speaker system is shown in FIG. As shown in FIGS. 4(a) and 4(b), a full-band reproduction speaker is mounted face down on the top surface of a cylindrical enclosure, and sound waves are radiated omnidirectionally in a horizontal plane. Furthermore, as shown in FIG. 4(c), there was also one that used a cylindrical enclosure with a square cross section. Such cylindrical enclosures are mainly made of paper or wood.

0003

[Problems to be Solved by the Invention] In the conventional device described above, since the cylindrical enclosure is made of paper or wood, the rigidity is insufficient, and the ratio between the length of the cylindrical enclosure and the wavelength of the sound wave is insufficient. There was a drawback that resonance occurred intensely at frequencies where the value was 1/2 to 1/4. Furthermore, although a wide reproduction sound field, which is a feature of omnidirectional speaker systems, can be achieved, there is a drawback that the sound field is deep, that is, the sound image position feels far away, creating a sense of incongruity with ordinary speaker systems.

[0004] This invention has been made in view of the above points, and its purpose is to improve frequency characteristics and reproduce a sound field that does not feel out of place with ordinary speaker systems. An object of the present invention is to provide a directional speaker system.

[0005]

[Means for Solving the Problems] The omnidirectional speaker system of the present invention has two dome speakers driven in the same phase facing each other, and a high-pitched speaker in which a horn is formed by a rotating curved surface extending around each diaphragm. A bass speaker is provided coaxially, the bass speaker is arranged so as to close an upper opening of a cylindrical enclosure, and a bass speaker is further arranged in an intermediate part of the cylindrical enclosure to face the bass speaker so as to be driven in the same phase, A plurality of sound wave emission windows are provided on the lower side of the cylindrical enclosure.

[0006] Furthermore, in the omnidirectional speaker system, a phase inversion port is provided between the two bass speakers.

Furthermore, in the omnidirectional speaker system, a wall surface of the cylindrical enclosure that is continuous with the sound wave emission window has a streamlined shape.

Furthermore, in the omnidirectional speaker system, the cylindrical enclosure is formed of unfired ceramic made of silica, fine sand, and cement.

Furthermore, in the omnidirectional speaker system, the cylindrical enclosure is formed into a circle, an ellipse, a polygon, or a combination thereof.

Furthermore, in the omnidirectional speaker system, a small speaker is attached to the middle part of the cylindrical enclosure so as to face the listening direction.

[0011] Furthermore, in the omnidirectional speaker system, the small speaker is provided with a volume adjustment device.

0012

[Operation] According to the omnidirectional speaker system of the present invention, high-pitched sound waves emitted from the diaphragms of the dome speakers arranged oppositely and driven in the same phase are guided by the horn around the diaphragm and are efficiently radiated in all horizontal directions. Ru. In addition, the bass speakers placed opposite to each other at the top and middle of the cylindrical enclosure are also driven in the same phase, so that bass sound waves are emitted in all horizontal directions from around the diaphragm of the top bass speaker and from the sound wave emission window of the cylindrical enclosure. radiated. By appropriately selecting the frequency characteristics of the dome speaker and the bass speaker, an omnidirectional speaker system with good overall frequency characteristics can be obtained.

[0013] When a phase inversion port is provided in the middle of the cylindrical enclosure of the omnidirectional speaker system, the anti-phase sound waves inside the cylindrical enclosure are inverted and become in phase with the sound waves radiated from above and below the cylindrical enclosure. Emitted from the phase inversion port, low frequency sound is radiated more efficiently.

The cylindrical enclosure is made of unfired ceramic made of silica, fine sand and cement to increase its rigidity, and is made to be circular, elliptical, polygonal or a combination thereof to make it less likely to vibrate.
Resonance of the cylindrical enclosure is prevented and frequency characteristics are improved.

[0015] Furthermore, by attaching a small speaker to the middle part of the cylindrical enclosure, facing the listening direction,
It is possible to alleviate the feeling of discomfort when compared to ordinary speakers, and by providing a volume adjustment device to a small speaker, a sound field that suits each viewer's preference can be obtained.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An omnidirectional speaker system which is an embodiment of the present invention will be described with reference to FIGS. 1 to 3. In FIGS. 1 and 2, 1 and 1 are dome speakers, and dome-shaped diaphragms 1a and 1a are coupled so as to face each other. In addition, the front surfaces of the frames also face each other, and the horn forming surfaces 1
b, 1b.

A bass speaker 2 is coupled to the lower dome speaker 1, and the bass speaker 2 is attached to the cylindrical enclosure 3 so as to close the upper opening of the cylindrical enclosure 3. A bass speaker 7 is installed at a position of 1/2 to 1/3 of the height of the cylindrical enclosure 3 so that its back face faces the bass speaker 2, and four sound wave emission windows 4 are provided at the bottom of the cylindrical enclosure 3. It is provided. A streamlined wall surface 6 is formed on a side wall of the cylindrical enclosure 3 that is continuous with the sound wave emission window 4, and a streamlined wall surface 6a is formed on the bottom surface of the cylindrical enclosure 3.

A phase inversion port 8 and a cavity 9 defined by a partition plate are provided at an intermediate position between the bass speaker 2 and the bass speaker 7, and a small speaker 10 is installed inside the cavity 9. Small speaker 10 is bass speaker 2
, 7 and the dome speaker 1, the volume can be adjusted by a volume control device separate from the dome speaker 1.

The cylindrical enclosure 3 is made of unfired ceramic made of silica, fine sand, and cement, and has high rigidity, and its outer periphery is a combination of polygons and circles, as shown in FIG. 2(b). It has a structure that does not easily vibrate, and does not cause sound distortion due to resonance.

In the above configuration, the dome speakers 1, 1
The bass speakers 2 and 7 are driven in the same phase. The high-pitched sound generated by the dome speakers 1 and 1 is generated by the horn forming surface 1.
b, 1b and is radiated omnidirectionally in the horizontal plane. Sound waves generated by the bass speaker 2 are radiated omnidirectionally from the top of the cylindrical enclosure 3 in a horizontal plane. Further, the sound waves generated by the bass speaker 7 are radiated omnidirectionally within the horizontal plane from the sound wave radiation windows 4, 4, . . . . The space between the bass speaker 7 and the bottom of the cylindrical enclosure 3 constitutes an acoustic filter 5, which attenuates high-pitched sounds. The length of the acoustic filter 5 is short compared to the wavelength, and the phase shift between the sound radiated from the upper part of the cylindrical enclosure 3 and the sound radiated from the sound wave emission windows 4, 4, . . . is small. In addition, since the wall surface connected to the sound wave emission windows 4, 4, . . . has a streamlined shape, the acoustic resistance is small. In the space between the bass speaker 2 and the bass speaker 7, a sound with a phase opposite to the sound radiated from the top and bottom of the cylindrical enclosure 3 is generated.
The signal is inverted and radiated from the phase inversion port 8. The bass speaker 7 is located 1/2 to 1 from the bottom of the cylindrical enclosure.
Since it is located at a height of /3, the standing wave frequency due to the length of the cylindrical enclosure increases and the resonant sound is attenuated. High-frequency sounds are radiated by the dome speakers 1 and 1, and low-frequency sounds are radiated by the low-frequency speakers 2 and 7. By appropriately selecting the frequency characteristics of these speakers, sound with good overall frequency characteristics can be radiated. Ru. small speaker 1
A reproduction image in which the radiated sound intensity in the radiation direction is expressed by distance when 0 is turned off is shown by the solid line in FIG.

When the volume of the small speaker is maximized, the reproduced image changes as shown by the dotted line in the figure, and the reproduced image can be adjusted between the solid line and the dotted line according to preference. Although the embodiment is configured as described above, the invention is not limited thereto, and the effects of the invention can be obtained even if, for example, the material and shape of the cylindrical enclosure are changed.

[0022]

[Effects of the Invention] The omnidirectional speaker system of the present invention is equipped with a dedicated bass speaker, and can provide an omnidirectional speaker system with a richer bass range than conventional speakers.

Furthermore, by driving the two bass speakers in the same phase, it is possible to reproduce a spacious sound, and the vibrations generated in the individual speaker units are canceled out.

Furthermore, if a small speaker is provided as shown in the embodiment, it becomes possible to adjust the reproduced image.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an omnidirectional speaker system according to an embodiment of the present invention.

FIG. 2(a) is a front view of the omnidirectional speaker system, and FIG. 2(b) is a sectional view taken along line AA in FIG. 2(a).

FIG. 3 is a diagram showing a reproduction image of the omnidirectional speaker system.

FIG. 4(a) is a cross-sectional view showing an example of a conventional omnidirectional speaker system, FIG. 4(b) is a perspective view showing the same omnidirectional speaker system, and FIG. 4(c) is an example of a conventional omnidirectional speaker system. FIG. 2 is a perspective view showing an example of an omnidirectional speaker system.

[Explanation of symbols]

1 Dome speaker 1a Dome-shaped diaphragm 1b Horn forming surface 2. Bass speaker 3. Cylindrical enclosure 4 Sound wave emission window 5. Acoustic filter 6 Streamlined wall surface 7. Bass speaker 8 Phase inversion port 9 Cavity 10 Small speaker

Claims (7)

[Claims] 1. A bass speaker is provided coaxially under a treble speaker in which two dome speakers driven in the same phase face each other and a horn is formed by a rotating curved surface extending around each diaphragm, and the bass speaker is mounted in a cylindrical enclosure. A bass speaker is further disposed in the middle part of the cylindrical enclosure so as to be driven in the same phase as the bass speaker, and a plurality of sound wave emission windows are provided on the lower side surface of the cylindrical enclosure. Omnidirectional speaker system. 2. The omnidirectional speaker system according to claim 1, further comprising a phase inversion port provided between said bass speakers. 3. The omnidirectional speaker system according to claim 1, wherein the wall surface of the cylindrical enclosure that connects to the sound wave emission window has a streamlined shape. 4. The omnidirectional speaker system according to claim 1, wherein the cylindrical enclosure is formed of unfired ceramic made of silica, fine sand, and cement. 5. Claim 1, wherein the cylindrical enclosure is formed into a circle, an ellipse, a polygon, or a combination thereof.
The omnidirectional speaker system according to claim 4. 6. The omnidirectional speaker system according to claim 1, wherein a small speaker is attached to an intermediate portion of the cylindrical enclosure so as to face in a listening direction. 7. The omnidirectional speaker system according to claim 6, wherein the small speaker is provided with a volume adjustment device.