JPH04247171A - Sound field creating device - Google Patents

Abstract

PURPOSE:To create plural sound fields easily by providing the first and the second sound reflecting plates at the specific positions relating to the first and the second speakers. CONSTITUTION:Along a flowing pool, the first sound reflecting plate 6A and the second sound reflecting plate 6B are set between each other separating a distance in which the first focal point FC of the first ellipse O1 formed by the sound reflecting plate 6A and the first focal point Fc of the second ellipse O2 formed by the sound reflecting plate 6B are coincident with each other. The first speaker 7A and the second speaker 7B are set at the second focal pint FA of the ellipse O1 and the second focal point FB of the ellipse O2 respectively. When a sound is generated from the speakers 7A and 7B, the sound is transmitted in the radial form, reflected by the inner surfaces of the sound reflecting plates 6A and 6B, and focused the focal points FC simultaneously. As a result, the border L between one side sound field A and the other side sound field B is made clear, and different musics and the like can be enjoyed each time the swimming position is changed.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a sound field creating device, and in particular a sound field that can easily create a plurality of different sound fields with clear boundaries without the need for partition walls or the like. This relates to a creation device.

0002

[Prior Art] In recent years, pools that combine the elements of swimming and playing in the water have become popular, unlike ordinary pools that simply hold water.
Large donut-shaped pools with water flowing in one direction are being built at amusement parks and are gaining popularity. In large-scale amusement facilities such as such lazy river pools, it is conceivable to create different sound fields in the amusement facilities as a means to further enhance entertainment. In other words, taking a loop-shaped flowing pool as an example, if different sound fields are created in the pool, swimmers can hear different music and sound effects each time they change their swimming position. The entertainment value of the lazy river can be further enhanced.

In order to create different sound fields in a flowing pool, for example, as shown in FIG. 2A and another pair of speakers 2B, 2B are installed facing each other at intervals along Pool 1, and different music and sound effects are played from each pair of speakers 2A and 2B toward Pool 1. , different sound fields A and B are created in pool 1. As a result, swimmers
You can listen to different music every time you change your swimming position.
This makes it possible to further enhance the entertainment value of the lazy river.

However, if the pair of speakers 2A and 2B are simply installed in the pool 1 as described above, the sound from one speaker 2A and the sound from the other speaker 2B will interfere with each other, and the sound field A and the sound from the other speaker 2B will interfere with each other. The boundary L with B becomes unclear. For this reason, swimmers can hear different music and sound effects each time they change their swimming position, and as a result, they cannot fully enjoy the effect of enjoying a more varied swimming experience.

Therefore, in order to make the boundary L between the sound field A caused by one speaker 2A and the sound field B caused by the other speaker 2B clear, as shown in FIG.
It is necessary to install a partition wall 3 between A and the other speaker 2B, that is, at the boundary L, or to make the speakers 2A and 2B directional speakers.

[0006]

[Problems to be Solved by the Invention] However, when the partition wall 3 is installed, visibility becomes poor and it becomes an obstruction to traffic. On the other hand, directional speakers are more expensive than ordinary speakers, and existing directional speakers have the problem that high output cannot be obtained due to their characteristics.

[0007] Therefore, an object of the present invention is to provide a sound field creation device that can easily create a plurality of sound fields having clear boundaries without using partition walls or directional speakers. It's about doing.

[0008]

[Means for Solving the Problems] The present invention provides first and second surfaces having inner surfaces curved in the shape of the long side ends of a spheroid.
It consists of an acoustic reflecting plate, and first and second speakers provided toward the inner surfaces of the first and second acoustic reflecting plates, and the first acoustic reflecting plate and the second acoustic reflecting plate are A first focal position of a first ellipse formed by one acoustic reflector, on the side far from the first acoustic reflector, and a second ellipse, formed by the second acoustic reflector, from the second reflector. and the first focal position on the far side are placed facing each other with an interval corresponding to each other, and the first focal position on the far side
The speaker is provided at a second focal position of the first ellipse closer to the first acoustic reflector, and the second speaker is provided at a second focal position of the second ellipse closer to the second acoustic reflector. It is characterized by being provided at two focal positions.

Next, the principle of the sound field generating device of the present invention will be explained with reference to the drawings. FIG. 1 is a sectional view showing the principle of the sound field generating device of the present invention, and FIG. 2 is a view taken along the line AA in FIG. As shown in FIGS. 1 and 2, this invention
This takes advantage of the geometric properties of a spheroid. That is, the acoustic reflection plate 4 is assumed to have an inner surface curved in the shape of the long side end of a spheroid. The acoustic reflection plate 4 has a substantially egg-shaped spheroid, so it has a cup-shaped curve. And, existing on the side closer to the inner surface of the acoustic reflector 4,
The first focal point (F1) of the ellipse formed by the acoustic reflector 4
) and emit sound from this sound source. The sound from the sound source propagates radially from the sound source, reflects on the inner surface of the acoustic reflection plate 4, and converges at the second focal point (F2) of the ellipse. At this time, the propagation distance of sound from the sound source to the second focal point (F2) of the ellipse after being reflected on the inner surface of the acoustic reflector 4 is as follows:
Equal in all sound propagation paths. Therefore, there is no difference in sound propagation time in each propagation path. For this reason, the sound from the sound source is directed to the second focal point (F2) of the ellipse.
It can be clearly heard only in the vicinity of the position, while it is extremely attenuated outside the second focal point (F2) position.

The inventor of the present application conducted the following tests in order to verify the principle of the sound field generating device of the present invention as described above. That is, as shown in FIG. 3, an acoustic reflecting plate 4 curved in the shape of the long side end of a spheroid is prepared, and the acoustic reflecting plate 4 is formed by the acoustic reflecting plate 4 located on the side closer to the inner surface of the acoustic reflecting plate 4. A speaker 5 was installed at the first focal point (F1) of the ellipse. Then, a sound with a constant sound pressure is continuously emitted from the speaker 5 toward the inner surface of the acoustic reflector 4, and the sound with a constant sound pressure of 1.5
Microphones are installed at the second focal point (F2) position of the ellipse which is located m away from the ellipse, and at a position P outside the acoustic reflector 4 which is 1.5 m perpendicularly away from the second focal point (F2) position. Focal point (F2) position and position P outside the acoustic reflector 4
The sound pressure level was measured at each position, and the sound pressure level difference between the two positions was measured. As a result, the sound pressure level difference between the second focal point (F2) position and the position P outside the acoustic reflector 4 is approximately 25 d.
It was B. FIG. 4 shows the relationship between the frequency and the sound pressure level at the second focal point (F2) position and the position P outside the acoustic reflector 4 at this time.

Next, the acoustic reflector 4 was removed, and the sound pressure level difference between the second focal point (F2) position and the position P outside the acoustic reflector 4 was measured in the same manner as described above. As a result, the sound pressure level difference was approximately 3 dB. Therefore, according to the present invention, as shown in FIG. 7, it has been found that, unlike the case where sound is simply emitted from a speaker, it is possible to easily create a plurality of sound fields having clear boundaries.

The present invention utilizes the above-mentioned principle, and next, one embodiment of the sound field generating device of the present invention will be described with reference to the drawings. FIG. 5 is a sectional view showing an embodiment of the sound field generating device of the present invention, and FIG. 6 is a view taken along the line AA in FIG. 5. As shown in FIGS. 5 and 6, the sound field generating device of the present invention includes first and second acoustic reflectors 6 each having an inner surface curved in the shape of the long side end of a spheroid.
A, 6B, and first and second speakers 7A, 7B provided toward the inner surfaces of first and second acoustic reflectors 6A, 6B, respectively. Since the first and second acoustic reflectors 6A and 6B are installed on a horizontal floor, they are not completely spheroidal, but have a flat bottom as shown in FIG. 6.

[0013] First acoustic reflector 6A and second acoustic reflector 6B.
is the first focal position (FC) of the first ellipse O1 formed by the first acoustic reflector 6A on the side far from the first acoustic reflector 6A, and the second focal point (FC) formed by the second acoustic reflector 6B. The first focal positions (FC) of the ellipse O2 on the side far from the second acoustic reflector 6B are spaced apart from each other by a matching distance and are placed facing each other. The first speaker 7A has a first acoustic reflector 6A having a first ellipse O1.
is provided at the second focal position (FA) on the side closer to the
The speaker 7B has a second acoustic reflector 6 of a second ellipse O2.
Provided at the second focal position (FB) on the side closer to B

Since the sound field creating device of the present invention is constructed as described above, the sound field creating device of the present invention can be installed along the flowing pool 1, for example, as shown in FIGS. 4 and 5. If a plurality of speakers are arranged side by side, the sound from the first and second speakers 7A and 7B in one sound field creation device and the first and second speakers 7A in the other sound field creation device
, 7B are unlikely to interfere with each other. Therefore, the sound field A caused by the speakers 7A and 7B in one sound field creation device and the speakers 7A and 7 in the other sound field creation device
Since the boundary L between sound field B and sound field B becomes clear, swimmers can hear different music and sound effects each time they change their swimming position, thereby further enhancing the entertainment value of the lazy river. can. It goes without saying that the present invention can be applied to other equipment in addition to the pool described above.

[0015]

[Effects of the Invention] As explained above, according to the present invention, multiple sound fields with clear boundaries can be easily created without using partition walls or directional speakers. Useful effects are produced.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the principle of a sound field generating device according to the present invention.

FIG. 2 is a view taken along line AA in FIG. 1;

FIG. 3 is a sectional view showing an experimental method for demonstrating the principle of the sound field generating device of the present invention.

FIG. 4 is a graph showing the relationship between frequency and sound pressure level at the second focal point (F2) position and at a position P outside the acoustic reflector.

FIG. 5 is a sectional view showing one embodiment of the sound field generating device of the present invention.

FIG. 6 is a view taken along line AA in FIG. 4;

FIG. 7 is a plan view showing a conventional sound field generating device.

FIG. 8 is a plan view showing a conventional sound field generating device.

[Explanation of symbols]

1 Pool 2A, 2B 5 Speaker 3 Partition wall 4 Acoustic reflector 6A First acoustic reflector 6B Second acoustic reflector 7A 1st speaker 7B 2nd speaker

Claims (1)

[Claims] 1. First and second acoustic reflectors having inner surfaces curved in the shape of long side ends of a spheroid, and a first acoustic reflector provided toward the inner surfaces of the first and second acoustic reflectors.
and a second speaker, and the first acoustic reflector and the second acoustic reflector are the first acoustic reflector on the side far from the first acoustic reflector of the first ellipse formed by the first acoustic reflector. installed facing each other with an interval such that a focal point position and a first focal position on the side far from the second reflecting plate of a second ellipse formed by the second acoustic reflecting plate coincide with each other; The first speaker is provided at a second focal position of the first ellipse on a side closer to the first acoustic reflector, and the second speaker is provided on a side of the second ellipse closer to the second acoustic reflector. A sound field creating device, characterized in that it is provided at a second focal position of.