JPH046599A - Acoustic device - Google Patents

Abstract

PURPOSE:To increase the level of a collected sound by arranging an acoustic tube for sound irradiation at one focus on an elliptic surface of rotation and arranging a speaker as a sound source outside a reflecting body. CONSTITUTION:The speaker 2 is fitted as the sound source to a support 1 which is fixed to a structure and the reflection body 5 which includes part of the elliptic surface 4 of rotation, which has one axis 3, e.g. perpendicular line as an axis of rotation and has two focuses S1 and S2 on the axis 3, as its internal surface is fitted to the support 1. The acoustic tube 6 is fitted extending from the speaker 2 to one focus S1 of the reflection body 5 and a nozzle 7 is fitted there while facing the center of the reflection body 5. The sound from the speaker 2 reaches the nozzle 7 through the acoustic tube 6 to irradiate the reflection body 5 and the sound is reflected by the reflection body 5 and converged on the focus S2 without leaking out. Consequently, a large output is obtained without disordering the sound field in the reflection body 5.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to an acoustic device, and more particularly to a sound @i! using the principle of an acoustic lens using a reflector. It is related to the device.

[Conventional technology]

Acoustic lenses emit sound waves from a sound source toward various curved reflectors that have a focal point, and converge and diffuse the reflected sound waves.The principle of this is known for a long time, and it is commonly used in outdoor music halls and other places. It can be used in buildings such as music halls.

However, most conventional audio systems are designed to distribute the sound throughout a large audience housed in the building.

In contrast, there is a desire to collect sound only to individuals or a limited number of people within a specific range, even within a single building, and to prevent sound from reaching the surrounding area. There is also. In particular, there is a strong desire to send loud audio only to people with hearing loss. As an audio device for this purpose, the present inventor proposed the devices shown in Japanese Patent Application No. 01-202601 and Japanese Patent Application No. 01-202602. This device is equipped with a reflector whose inner surface is a curved surface with two focal points. A sound source such as a speaker is placed at one focal position, and an individual listens to the sound at the other focal position where the sound is collected by reflection. This is how it was done. Therefore, only the person at the other focal position can hear the loud sound without affecting the surroundings outside the range.

[Problem to be solved by the invention]

However, only a very limited number of people located at the other focal point or in the vicinity can hear the collected loud sounds.

In addition, the size of a reflector that accommodates such a small number of people is limited, and placing a speaker at one of the focal points in the reflector requires that the size of the speaker box occupies a large proportion of the reflector. In this case, the speaker box causes diffused reflection, which is undesirable. However, if the speaker box is made small, sufficient audio output cannot be obtained.

The primary purpose of the present invention is to solve such problems and provide an acoustic device that can obtain high output without using speakers that cause diffuse reflection.Furthermore, even if speakers are used, the reflector can be used in a state where the influence is extremely small. The second purpose is to provide an audio device that is large enough to allow a large number of specific people to listen to audio.

[Means to solve the problem]

The first purpose is to provide a reflector whose inner surface forms part of an ellipsoid of revolution with two focal points, and a sound source that extends from a sound source provided outside the reflector to the position of one focal point of the reflector. This is achieved by the first invention, comprising: a sound conduit whose opening is directed toward the inner surface of the reflector at the position of the one focal point.

The second purpose is to create a reflector whose inner surface is a paraboloid of revolution at its center and whose surroundings are part of an ellipsoid of revolution with two focal points, and a sound source placed at one of the focal points of the reflector. This is achieved by a second invention comprising the following.

In addition, the second object is to provide a reflection system in which the inner surface shape in one cross section has a part of an ellipse with two focal points, and the part of the ellipse extends in a direction perpendicular to the cross section. This is also achieved by the third invention, which includes a body and a sound source disposed at one focal point of the reflector.

[Effect]

In the first invention, the sound from the sound source passes through the sound pipe, is irradiated onto the reflector through the tip opening of the sound pipe located at one focus of the spheroid, and is collected at the other focus. At this time, unlike the conventional case in which a speaker is placed at one focal point, it is possible to emit audio with as much output as desired without disturbing the sound field.

As a result, sufficient audio can be heard even in a spheroid with a small diameter.

According to the second invention, the sound emitted from one focal point is reflected in parallel within the range of the paraboloid of revolution at the center, and is reflected in the direction toward the focal point by the ellipsoid of revolution at the periphery. Therefore, a plurality of specific people can listen to the audio within the range of the paraboloid of revolution without affecting the outside world.

Further, in the third invention, a plurality of specific persons can listen to audio within a band-shaped range having a width centered around another focal point extending in a band-shape.

In addition, in the second and third inventions, since the reflector can be made relatively large, the size of the speaker box does not occupy a large proportion of the reflector, so the influence of diffused reflection is small and the sound source is A speaker can also be used.

〔Example〕

Hereinafter, the present invention will be described in detail based on the accompanying drawings.

In the first embodiment shown in FIG. 1, l is a support fixed to the horizontal object, and a speaker 2 is attached as a sound source.

The support 1 has one axis 3, for example, a vertical line in the case of M, as the axis of rotation, and a reflector whose inner surface is a part of an ellipsoid of revolution 4 having two focal points S1 and S2 on the axis 3. 5 is attached. .

Furthermore, a sound pipe 6 is provided extending from the speaker 2 toward one focal point S+ of the reflector 5 (in the case shown, the upper focal point), and a nozzle 7 is installed therein toward the center of the reflector 5. installed. Note that, even without using the above-mentioned nozzle, it is sufficient if the tip opening of the sound guide tube is directed toward the reflector and its shape is suitable for irradiating sound.

In the device of this embodiment, when a sound is emitted from the speaker 2, the sound passes through the sound pipe 6 and reaches the nozzle 7 located at the focal point S1, and is irradiated from the nozzle 7 toward the reflector 5. The sound is reflected by the reflector 5 and collected at the focal point S2 without leaking to the outside. Therefore, the user can listen to the collected sounds by placing his or her head at the focal point S2. At this time, in this embodiment, since the speaker 2' is placed outside the reflector 5, a large output can be achieved without disturbing the sound field inside the reflector 5.

Next, according to the first embodiment shown in FIG.
The range in which audio can be heard can be expanded around 2, and the audio level within that range becomes fairly uniform.

In this embodiment, the inner surface of the reflector 5' is formed by a paraboloid of revolution 5'A in the center centering on the axis vA3, and an ellipsoid of revolution 5'B at the peripheral part.

In this embodiment, the sound source disposed at the focal point S can be used as a sound source by increasing the diameter of the reflector and reducing the influence of the speaker box, instead of using a nozzle as in the previous embodiment. can.

In this embodiment, the sound is transmitted through the paraboloid of revolution 5 at the center.
'Reflected in parallel at A.

On the other hand, on the periphery of the spheroidal surface 5'B, the sound is focused at S2.
The sound is reflected from the paraboloid of revolution 5'A and mixed with the sound reflected from the paraboloid of revolution 5'A. Therefore, a predetermined sound level can be obtained within the range of the paraboloid of revolution 5', and many people can listen to the sound within this range. Furthermore, the audio level within that range is fairly uniform.

In this embodiment, by adjusting the area of the paraboloid of revolution 5'A, it is possible to accommodate the number of people listening to the audio.

Further, the number of users can be increased by a third embodiment having a reflector 5'' whose cross section is shown in FIG. 3. In FIG. 3, the inner surface shape of the reflector 5'' is By having a part of an ellipse with two foci in one cross section and extending to the above cross section, the range of the other foci is expanded linearly, and the user can You can listen to the collected audio. The above range is actually wide enough to hear audio at a linear focal point.
It becomes a band shape. Note that in this embodiment as well, a speaker can be used as a sound source, as in the case of the second embodiment.

〔Effect of the invention〕

According to the present invention as described above, the following effects are obtained.

First, in the first invention, a sound pipe that emits sound is placed at one focal point of the spheroid, and the sound source, such as a speaker, is placed outside the reflector. Even when using an output speaker, it does not disturb the sound field inside the reflector,
As a result, it becomes possible to make the collected sound higher than the predetermined level.

Next, in the second invention, a paraboloid of revolution is provided in the center of the reflector so that the sound is reflected in parallel within that range, so multiple people can listen to the collected sound within that range. make it possible.

Furthermore, in the third invention, since the range of other focal positions can be extended linearly, multiple people can listen to the collected sounds in a band-shaped range formed around this focal position. is possible.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of the device of the first embodiment of the present invention, Fig. 2 is a longitudinal cross-sectional view of the device of the second embodiment, and Fig. 3 is a cross-sectional view of the reflector in the device of the third embodiment. be. 2・・・・・・・・・・・・・・・Sound source 4・・・・・・
......Spheroidal surface 5:5"=5-...
・Reflector

Claims (3)

[Claims] (1) A reflector whose inner surface forms part of an ellipsoid of revolution with two focal points, and a sound source provided on the outside of the reflector that extends from a sound source to the position of one of the focal points of the reflector, and an aperture at the tip of the reflector. An acoustic device comprising: a sound conduit directed toward the inner surface of a reflector at a focal point of the reflector; (2) A reflector whose inner surface has a central part as a paraboloid of revolution and whose peripheral part is part of an ellipsoid of revolution with two focal points, and a sound source placed at one of the focal points of the reflector. A sound device was prepared. (3) A reflector whose inner surface shape in one cross section has a part of an ellipse with two focal points, and a part of the ellipse extends in a direction perpendicular to the cross section; An acoustic device comprising: a sound source placed at one focal point;