JPH0479500A - Speaker system - Google Patents

Abstract

PURPOSE:To secure directivity sufficient in practical use and to attain miniaturization by providing a reflection plate protrusively at a speaker unit side position for high-frequency sound in the arranging direction of speaker units for low-frequency and high-frequency sound by extending the front in the acoustic radiating direction of the speaker units for low-frequency and high-frequency sound. CONSTITUTION:The speaker unit 2 for low-frequency sound and the speaker unit 3 for high-frequency sound are arranged in in-line shape so that the center axes of them can be located on the same line at the baffle plane of an enclosure 1, and the reflection plate 6 extending to the front in the acoustic radiating direction of the speaker units 2, 3 for low-frequency and high-frequency sound is provided protrusively at the speaker unit 3 side terminal part for high-frequency sound in the arranging direction of the speaker units 2, 3 for low-frequency and high-frequency sound. Therefore, it is possible to perform a function equivalent to that speaker units 4, 5 for virtual low-frequency and virtual high- frequency sound exist by a mirror image principle at the symmetric position of the speaker units 2, 3 for low-frequency and high-frequency sound centering the reflection plate 6. In such a way, narrow directivity in a vertical direction can be obtained, and also, the miniaturization can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a speaker system used as a surround speaker of an audio device, and more particularly to a narrow directional speaker system.

[Conventional technology]

Generally, a surround method is known as a method for creating a sound field feeling similar to the acoustic characteristics of a large hall, a small hall, etc. in a sound field space such as a listening room. In the surround system, in addition to front speakers (a pair of left and right speakers) placed in front of the listener, effect speakers (sub speakers) that emit reflected sound are used.

In a surround sound system, the presence of the speakers, such as the sound being emitted from the speakers, actually produces a negative effect, so it is necessary to devise ways to make the position of the sound source, that is, the position of the speakers, as invisible to the listener as possible. One method for this purpose is to reduce the presence of the speakers by reflecting the sound on the walls around the listener in the listening room. Effect speakers are used to actively radiate such reflected sound.

It is more effective to reflect the radiated sound not only from one wall but from all walls surrounding the listener. Furthermore, the longer the relative distance between the reflecting wall and the effect speaker, the longer it takes for the reflected sound to reach the listener, which is more effective in making it seem as if the effect speaker is far away. On the other hand, in order to simplify the device configuration of the surround system, it is preferable to have fewer effect speakers.

FIGS. 11 to 17 show examples of conventional effect speaker systems configured with one speaker system. As shown in the plan view of FIG.
02 is arranged, and an effect speaker 103 is arranged at the rear upper part of the listener 112. The direction in which the effect speaker 103 emits sound waves is behind and to the left and right of the listener 112, and the emitted sound waves are reflected on the inner wall surface of the acoustic space 100 and reach the ears of the listener 112. In this way, by using reflected sound, as shown in the figure, it is as if the virtual sound source speaker 1 is outside the acoustic space 100.
04.105.106 can be created. FIG. 12 is an elevational view of FIG. 11.

As shown in FIG. 12, the effect speaker 103
is suspended from the ceiling of the acoustic space 100, and the reflected sound emitted from the rear reaches the listener 112 through the illustrated path.

FIG. 13 shows an example of a conventional effect speaker 03. This effect speaker 03 is enclosure 1
Bass speaker unit 1 on the outside on the baffle surface of 07
08.109, treble speaker unit 110 inside
．． 111 are arranged in-line. As shown in FIG. 14, each of the bass speaker unit 108, the treble speaker unit 110, and the bass speaker unit 109 and the treble speaker unit 111 has their own reproduction band at an appropriate division frequency (crossover frequency) f. Assigned.

The arrangement interval (center to center) D between the bass speaker unit 108 and the treble speaker unit 109 is D-λ.
...It is given by (1). Here, λ is the C wavelength of the division frequency f, and is given by λ −1/C (2) C: the speed of sound. On the other hand, the arrangement interval d between the treble speaker system 110 and the treble speaker system 111 is given by d-(D/4)±50% (3).

According to the effect speaker 03 described above, narrow directivity is provided in the θ direction (horizontal direction) shown in FIG. However, the direction perpendicular to this θ direction, that is, the vertical direction, is
Since it is determined by the directivity of each unit of the bass speaker system 108 to treble speaker system 110, it is neither omnidirectional nor narrowly directional. FIG. 15 shows the directivity characteristics of the effect speaker 03 which is thus provided with narrow directivity in the θ direction. As can be seen from FIG. 15, θ-0' (on-axis sound pressure level) exhibits a flat characteristic, and the sound pressure level decreases as θ=60° to θ-90°.

FIG. 16 shows the configuration of a speaker system based on simulation, and FIG. 17 shows the directivity characteristics as the simulation results.

[Problem to be solved by the invention]

The problems with the conventional effect speaker 103 are, firstly, that the directivity required to effectively produce a surround effect is not sufficient, and secondly, the external size of the speaker system is large.

In other words, regarding the first point above, the basic performance that an effect speaker system should have is 36 in the horizontal direction.
It is desirable to have omnidirectionality at 0° and narrow directivity in the vertical direction. Under these conditions, the sense of surround sound is improved by diluting the presence of the speakers and effectively emitting reflected waves. However, the above-described conventional effect speaker 103 has narrow directivity in the horizontal direction and is equivalent to a normal speaker in the vertical direction, and is not sufficient for the above-mentioned basic performance.

The second point is a problem that arises from the relationship with the height of the ceiling in a typical home and the relationship with the size reduction that is normally required. Generally, the ceiling height is about 2.3 to 2.5 m, and when the effect speaker system is suspended from the ceiling as shown in FIG. 12, it is desirable that the effect speaker system be as small as possible. However, in order to obtain a good surround sound, it is necessary to extend the frequency response to the bass range and create a narrow directivity. In order to obtain narrow directivity down to the bass range, it is necessary to lower the division frequency f 2 as shown in equations (1) and (2) above.

Lowering the division frequency f 2 means increasing the spacing between the bass speakers 08 and 109, which inevitably increases the external dimensions of the enclosure 1.

SUMMARY OF THE INVENTION An object of the present invention is to provide a speaker system that secures practically sufficient directivity and can be made smaller.

[Means to solve the problem]

In order to solve the above problem, the first invention according to claim 1 includes a set of bass speaker units and treble speaker units, each of which is assigned a reproduction frequency band at a predetermined divided frequency, and is mounted on a support. , a reflecting plate extending forward in the sound radiation direction of each of the speaker units is provided at a position on the high-pitched speaker unit side of the support body in the arrangement direction of the speaker units.

A second invention according to claim 5 has a pair of bass speaker unit and treble speaker unit to which respective reproduction frequency bands are assigned at predetermined divided frequencies, and a pair of bass speaker units and a treble speaker unit are arranged in front of the bass speaker unit in a sound radiation direction. A reflecting plate is disposed at a position facing the diaphragm of the bass speaker unit and with an interval of approximately 1/2 of the wavelength of the divided frequency between the diaphragm and the diaphragm of the bass speaker unit. The treble speaker unit is disposed between the reflector and the bass speaker unit in the same direction as the bass speaker unit.

[Operation 1] According to the first invention described in claim 1, the sound radiation direction of the bass speaker unit and the treble speaker unit is located at the position on the treble speaker unit side in the arrangement direction of the bass speaker unit and the treble speaker unit. By extending the reflector in front, it acts equivalently to an imaginary sound source existing at the target position of the bass speaker unit and treble speaker unit with the reflector as a boundary due to the mirror image principle, resulting in narrow directivity. It is possible to provide a speaker system with

According to the second invention as set forth in claim 5, the reflection plate is disposed in front of the bass speaker unit and the treble speaker unit in the sound radiation direction, facing the diaphragm of the bass speaker unit. ° Omnidirectional, providing a vertically narrow directional speaker system.

〔Example〕

Next, embodiments of the present invention will be described based on the drawings.

First Embodiment FIGS. 1 to 7 show an embodiment (hereinafter referred to as the first embodiment) according to the invention described in claim ↑.

In FIG. 1, an enclosure 1 having a suitable volume is shown.
A bass speaker unit 2 and a treble speaker unit 3 are arranged in-line on the baffle surface so that their central axes are located on the same line. At the end of the enclosure 1 on the treble speaker unit 3 side in the arrangement direction of the bass speaker unit 2 and treble speaker unit 3, there is a reflection that extends forward in the acoustic radiation direction of the bass speaker unit 2 and the treble speaker unit 3. A plate 6 is provided protrudingly. The bass speaker unit 2 maintains a distance of D/2 between its center axis and the reflector 6, and the treble speaker unit 3 maintains a distance of d/2 between its center axis and the reflector 6.
They are arranged to maintain a certain distance from each other. The reflecting plate 6 is usually rectangular, but a circular plate or the like may also be used.

However, the length of one side of the reflection plate 6 is the wavelength λ of the division frequency f.

It has been experimentally confirmed that if the diameter is twice or more, characteristics comparable to those of the effect speaker 03 shown in FIG. 13 can be obtained (see FIGS. 2 to 5).

When a circular plate is used as the reflecting plate 6, the length L of the reflecting plate 6 is equal to the diameter of 2λ as described above.

In this way, the effect speaker 103 shown in FIG.
By paying attention to the symmetry of the speaker arrangement, and providing the reflector 6 at the center line position, the necessary narrow directivity can be made 1/2 the size and 1/2 the size of the effect speaker 03.
This can be realized with the number of speaker units of 2. In other words, due to the presence of the reflector 6, a virtual bass speaker unit 4 and a virtual treble speaker unit 5 are present at symmetrical positions of the bass speaker unit 2 and the treble speaker unit 3 with the reflector 6 as the center, due to the mirror image principle. It becomes possible to perform an effect equivalent to that of

FIG. 2 shows a perspective view of the speaker system when the reflection plate 6 is a dog-sized rectangular plate measuring 400 mm×600+ nm, and FIG. 3 shows the frequency characteristics of the simulation results in that case. As can be seen from Fig. 3, when observation is made by sequentially changing the angle in the θ (horizontal) direction from when the extending direction of the reflector 6 is 0° on the axis, the sound pressure level decreases in the high frequency range. can be seen. This means that it has narrow directivity in the θ direction.

FIG. 4 shows a perspective view of the speaker system when the reflecting plate 6 is a rectangular plate with a size of 1000+nm×1000 mm, and FIG. 5 shows the frequency characteristics of the simulation results in that case. As can be seen from FIG. 5, increasing the area of the reflector 6 shifts the directivity change band to the low frequency range. Similarly, when the extending direction of the reflector 6 is set to 0° on the axis, when the angle in the θ direction is sequentially changed and observed, the sound pressure level decreases significantly in the middle to high frequency range. That is, as the area of the reflector 6 increases, the band affected by the directivity shifts to the bass side, and the directivity becomes narrower in the θ direction.

Examples of the case where the above speaker system is used as a speaker system for a television device are shown in FIG. 6 (front view) and FIG. 7 (side sectional view). As shown in FIG. 6, the speaker system 8 is installed with the reflector 6 facing forward, that is, the bass speaker unit 2 and the treble speaker unit 3 are located at the back of the reflector 6. . As shown in more detail in FIG. 7, the speaker system 8 is mounted so that it can be rotated and pulled out forward. The cabinet 11 also serves as a stand for the television device 7, and a horn-shaped baffle plate is provided at an intermediate portion in the front-rear direction to partition the inside of the cabinet 11 into front and rear sections. This baffle plate has a super bass speaker unit 1 with the space behind it as a pack cavity.
0 is attached. Furthermore, the speaker system according to this embodiment is rotatably mounted in a space on the front side of the cabinet 11 partitioned by a baffle plate.

As shown in FIG. 7, the speaker system has a reflector 6 located at the frontmost side, and an enclosure 1 at the back side.
are installed so that the arrangement direction of the bass speaker unit 2 and the treble speaker unit 3 is along the front-rear direction of the cabinet 11. Bass speaker unit 2
, the top surface of the high-pitched speaker unit 3 (radiation direction of sound waves)
A filter 12 is attached to the. The filter 12 is connected to the bass speaker unit 2 and the treble speaker unit 3.
This is an auxiliary member for making the directivity even narrower in the direction along the arrangement direction of the bass speaker unit 2 and the treble speaker unit 3, and the directivity in the left and right directions toward the screen of the television device 7. Does not affect sex.

In the above configuration, when the speaker system is not in use, the speaker system is housed in the cabinet 11, as shown by the broken line in FIG. When in use, as shown by the solid line, it is locked at a predetermined rotational position by pulling it out forward, and at that time, the direction of sound emission is directed toward the television device 7.
It is set in the direction toward the glass plate 9 placed in front of the.

When the bass speaker unit 2 and the treble speaker unit 3 are driven in this state, the reproduced sound is reflected by the glass plate 9 and reaches the viewer. Even in this kind of usage,
Due to the mirror image principle, an imaginary sound source exists at a symmetrical position of the reflector 6,
Narrow directivity can be obtained.

In the above explanation, the reflector 6 is provided as a single unit, but as can be seen from FIGS. 4 and 5, the directivity and the frequency band that affects the directivity are determined by the length of one side of the reflector 6. (
It is also possible to use the inner wall of the acoustic space instead of a board, depending on the area (or area).

Second Embodiment FIGS. 8 to 10 show an embodiment (hereinafter referred to as the second embodiment) according to the fifth aspect of the invention. The feature of this embodiment is that in the first embodiment, the reflector 6 extends in the sound radiation direction on the sides of the bass speaker unit 2 and the treble speaker unit 3, whereas the reflector 19 extends in the sound radiation direction. This is because the speaker unit 13 is arranged in a direction perpendicular to the acoustic radiation direction of the speaker unit 13, that is, in a direction facing the diaphragm.

First, as a basic performance of a surround speaker system, it is desirable to have omnidirectionality in the horizontal direction of 360 degrees and narrow directivity in the vertical direction (see FIGS. 11 and 12). To do this, as shown in FIG. 8, the bass speaker unit 13, the treble speaker unit 14, the bass speaker unit 15, and the treble speaker unit 16 are stacked vertically on the central axis x-x', and each Center plane (horizontal plane)
Arrange symmetrically with respect to A. However, when installing a surround effect speaker system by hanging it from the ceiling, the height of the speaker system becomes a problem. Therefore, by utilizing the symmetry of the arrangement of the speaker units and the mirror image principle shown in Fig. 8, the speaker system can be made into one.
/2 height and 1/2 the number of units. FIG. 9 shows an embodiment that takes such points into consideration.

As shown in FIG. 9, a bass speaker unit 13 is attached to the vertical surface 18, and the back of the bass speaker unit 13 is covered with a bass cavity 20 to ensure the necessary volume.

A position facing the diaphragm of the bass speaker unit 13 at a distance of D/2 in front of the bass speaker unit 13 in the sound radiation direction (upward in the drawing) (parallel to the vertical plane 18)
A reflector plate 19 is arranged at. D is the size shown in the above formula (1). A treble speaker unit 14 whose back portion is covered by a treble cavity 21 is coaxially mounted between the reflector 19 and the bass speaker unit 13 along the central axis X-X'. The high-pitched speaker unit 14 is supported on a vertical surface 18 by a support 22.

In consideration of the acoustic resistance of the sound waves emitted from the bass speaker unit 13, the high-pitched sound cavity 21 preferably has an outer surface having a substantially spherical shape or a curved surface as shown in the figure. It is preferable that the number of pillars 22 is appropriate in consideration of the acoustic resistance mentioned above so that they do not become an obstacle. The distance between the acoustic radiation surface of the high-pitched speaker unit 14 and the reflection plate 19 is d/2, where d is the size shown in equation (3) above. moreover,
A plurality of ring-shaped filters 23 are arranged at intervals between the vertical surface 18 and the reflection plate 19. The filter 23 is made of a highly sound-absorbing material such as glass wool felt, and is designed to increase the acoustic resistance in the vertical direction (X-X' force direction and further narrow the directivity of the high frequency range in the vertical direction). It is.

With the above configuration, the speaker system shown in FIG. 9 can have characteristics of omnidirectionality in the horizontal plane of 360 degrees and narrow directivity in the vertical direction. In addition to this, due to the interposition of the symmetrical reflector 19 and the mirror image principle as shown in FIG. One of the units 16 can be omitted, the external dimensions (especially height) can be reduced to 1/2, and the number of units can be reduced to 1/2. However, in order to omit one of the sets in this way, it is preferable that the reflector 19 is a completely reflective surface, and for that purpose, the length of one side of the reflector 19 (
It has been confirmed that there is no practical problem if the diameter (or diameter) is approximately C degrees equivalent to twice the wavelength (2λ) of the division frequency f, and it is possible to go further and utilize the ceiling surface of the acoustic space 100. It is. According to experiments, the axis of the maximum sound pressure level on the plane showing narrow directivity (vertical plane, see FIG. 8) is not parallel to the reflector 19, but slightly parallel to the bass speaker unit 13.
The direction was tilted to the side (downward). This inclination angle is related to the size of the reflecting plate 19, and the larger the angle, the shallower the angle (that is, the closer to parallel to the reflecting plate 19). It has been confirmed that when the size of a practical reflector is approximately 50 cm to 100 cm on a side, the angle of inclination is approximately 15° to 30°.

As described above, according to this embodiment, a surround speaker system having omnidirectionality in the horizontal direction of 360° and narrow directionality in the vertical direction can be realized with half the size and half the number of units.

FIG. 10 shows an example of use of the speaker system of the second embodiment. That is, the reflecting plate 19 is placed along the ceiling surface 24 of the listening room and fixed so that the side wall surface faces the sound wave emission surface. By arranging it in this way, the virtual sound source speaker unit 13A is placed above the ceiling surface using the mirror image principle.
exists, and the virtual sound source speaker unit 2 is located in the horizontal direction.
6 exists, and it is possible to obtain good narrow directivity and good reflected sound.

〔Effect of the invention〕

As described above, according to the first aspect of the invention, it is possible to miniaturize a speaker system that has narrow directivity in the vertical direction and is suitable for a surround speaker system.

Further, according to the invention described in claim 5, 360° in the horizontal direction
It has characteristics of omnidirectional in the vertical direction and narrow directivity in the vertical direction, and it is possible to miniaturize a speaker system suitable for a surround speaker system.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the first embodiment of the present invention, FIG. 2 is a perspective view showing an example of the speaker system of the first embodiment, and FIG. 3 is a characteristic showing the frequency characteristics of the speaker system of FIG. 2. 4 is a perspective view showing another example of the speaker system of the first embodiment, FIG. 5 is a characteristic diagram showing the frequency characteristics of the speaker system of FIG. 4, and FIG. 6 is a television apparatus of the present invention. 7 is a side sectional view of FIG. 6, FIG. 8 is a perspective view showing the principle configuration of a speaker system according to a second embodiment of the present invention, and FIG. 9 is a second embodiment of the present invention. A vertical cross-sectional view showing an example, FIG. 10 is an explanatory diagram of the operation of the second embodiment, FIG. 11 is a plan view showing an example of the arrangement of a general surround speaker system, FIG. 12 is an elevational view of FIG. 11, Fig. 13 is a configuration diagram showing an example of a conventional surround speaker system, Fig. 14 is a frequency division characteristic diagram of the speaker system of Fig. 13, Fig. 15 is a characteristic diagram showing the directivity of the speaker system of Fig. 13, FIG. 16 is a perspective view showing an example of a conventional surround speaker system, and FIG. 17 is a characteristic diagram showing the directivity of the speaker system shown in FIG. 18... Vertical surface 19... Reflector plate 20... Bass cavity 21... Treble cavity 22... Pillar 23... Filter 24... Ceiling surface 25... Side wall surface 26. ...Imaginary sound source speaker 100...Acoustic space 101...Front speaker 102...Front speaker 103...Effect speaker 104...Imaginary sound source speaker 105...Imaginary sound source speaker 106...Imaginary sound source speaker 107... Enclosure 108... Bass speaker unit 109... Bass speaker unit 110... Treble speaker unit 1... Enclosure 2... Bass speaker unit 3... Treble speaker unit 4...Virtual bass speaker unit 5...Virtual treble speaker unit 6...Reflector 6A...Reflector 6B...Reflector 7...Television device 8...Speaker system 9 ...Glass plate 10...Super bass speaker unit 11...Cabinet 12...Filter 13...Bass speaker unit 14A...Imaginary sound source speaker unit 14...Treble speaker unit 15 ...Bass speaker unit 16...Treble speaker unit 17...Horizontal surface 111...Treble speaker unit 112...Listener

Claims (1)

[Claims] 1. A pair of bass speaker units and treble speaker units, each of which is assigned a reproduction frequency band at a predetermined divided frequency, is attached to a support, and placed at a position on the treble speaker unit side of the support in the arrangement direction of each of the speaker units. A speaker system comprising: a reflecting plate extending in front of each of the speaker units in a sound radiation direction. 2. 2. The speaker system according to claim 1, wherein the reflector is provided at a position on the support body at a length of about 1/2 of the wavelength of the divided frequency from the center of the bass speaker unit. . 3. 3. The speaker system according to claim 1, wherein the reflector has a length on one side or a diameter that is at least twice as long as the divided frequency. 4. 4. The speaker system according to claim 1, wherein the support body is an enclosure that covers a back space of the bass speaker unit. 5. It has a pair of bass speaker units and treble speaker units to which respective playback frequency bands are assigned at predetermined divided frequencies, and a diaphragm of the bass speaker unit is located in front of the bass speaker unit in the sound radiation direction. A reflecting plate is disposed facing each other and with an interval of approximately 1/2 of the wavelength of the divided frequency between the diaphragm of the bass speaker unit, and the reflecting plate and the bass speaker unit. A speaker system characterized in that the treble speaker unit is arranged between the bass speaker unit and the treble speaker unit in the same direction as the bass speaker unit. 6. 6. The speaker system according to claim 5, wherein each of the bass speaker unit and the treble speaker unit is attached to an enclosure having mutually independent back cavities. 7. 7. The speaker system according to claim 6, wherein the enclosure of the treble speaker unit has a spherical outer surface. 8. In the speaker system according to claim 5, 6 or 7, a high-frequency acoustic filter for attenuating high-frequency sound waves is interposed in the space between the support body and the reflection plate of the bass speaker unit. Features speaker system.