JPH04373398A - Speaker device for transmission video projector - Google Patents

Abstract

PURPOSE:To improve the clearness of sounds by improving the radiation state of an acoustic wave from a speaker at the time of arranging the speaker under a picture, namely, in the vicinity of the floor surface of a room where a transmission video projector is installed. CONSTITUTION:An elevation angle alpha is given to a baffle 7 and a subbaffle 15 to which the speaker is attached. A fulcrum 16 of a hinge is provided in the top part of the subbaffle 15 to couple the subbaffle to a baffle 7a, and the elevation angle of the subbaffle 15 is changed in accordance with the distance of attention.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speaker device for sound reproduction in a large-screen transmissive video projector or television set.

0002

2. Description of the Related Art In recent years, large-screen transmissive video projectors or television sets have become popular. In order to reproduce stereo sound with these devices, it is desirable to place speakers on the left and right sides of a screen or cathode ray tube, but this increases the width of the transmissive video projector or television set itself.
Generally, speakers are often placed below the screen.

For example, as shown in FIG. 8, in a transmissive video projector 51 (other name: rear projection television), the screen 55 is A speaker 56 is often placed below.

[0004] In this case, the baffle 57 to which the speaker 56 is attached is arranged perpendicular to the floor surface 58.

The reason for this is that the projection type video projector 5
Since the casing 1 is large in size, it is often made of wood, and since it is assembled using wood cut parallel and at right angles, the baffle 57 is generally perpendicular to the floor. This is because it is composed of

However, if the speaker 56 is placed below the screen 55 and perpendicular to the floor 58, as shown in FIG.
Since the ear height H of the viewer 59 is higher than IS), the viewer 59 will hear audio with less high-frequency components that have a directional characteristic.

[0007] For this reason, in order to improve the clarity of speech, components in the middle and high ranges are necessary, but the sound pressure level in the middle and high ranges has decreased compared to the low range. Furthermore, the direct sound 60 emitted from the speaker has acoustic characteristics that are interfered with by the reflected sounds 61a and 61b reflected from the floor 58.

[0008] For this reason, the acoustic characteristics heard by the audience are such that the low and mid ranges are raised even if the sound pressure frequency characteristics A measured in an anechoic chamber are flat, as shown in FIG. , furthermore, the sound pressure frequency characteristic (b) that causes peak p and dip d is obtained. This characteristic is based on the conditions of the floor surface 58 (wooden floor,
(carpet, tatami, etc.) and the installation height h of the speaker 56
Although it varies depending on the equipment, the deviation can be as high as 6 to 20 dB, resulting in excessive low frequencies and muffled and unclear audio reproduction.

This drawback can be solved by increasing the mounting height h of the speaker 56, but since the position of the screen 55 is limited by the height of clear vision, the height h of the speaker 56 is naturally increased.
6 is located below the screen 55, resulting in this drawback.

[0010] As a method to compensate for these drawbacks, the method shown in Fig. 10 (
The configurations shown in A) and (B) may be adopted. Figure 10 (
As shown in the cross-sectional views and front views of A) and (B), in order to radiate sound waves in the direction of the viewer 59, a sub-baffle 62 is provided on the speaker 56 by recessing a part of the baffle on which the speaker is attached. It has an elevation angle.

However, in this method, since the sub-baffle 62 is recessed, the sound waves conversely cause a resonance phenomenon in the recessed part, resulting in a specific sound pressure frequency characteristic as shown in FIG. 9. It has the disadvantage that it promotes peak p and dip d in the frequency band, and also produces muffled and unclear speech.

0012

[Problems to be Solved by the Invention] In this way, in the prior art, a part of the sound waves emitted from the speaker 56 is reflected by the floor surface 58 and interferes with the direct wave 60 that propagates directly from the speaker 56 to the viewer 59. However, there was a problem in that the sound pressure frequency characteristics were disturbed and the clarity of the voice was impaired.

The object of the present invention is to reduce the reflected waves 6 from the floor surface 58.
An object of the present invention is to provide a method for attaching a speaker 56 in order to reduce interference with the direct wave 60 radiated from the speaker 56 and obtain reproduced sound with good clarity.

[0014]

[Means for Solving the Problems] In order to achieve the above object, the main body of a transmissive video projector is configured such that the baffle to which the speaker is attached has an elevation angle in whole or in part so that the speaker has an elevation angle.

[0015] Furthermore, the speaker is composed of a baffle and a sub-baffle, and the speaker is attached to the sub-baffle with an elevation angle.
Furthermore, it is attached to a vertically configured baffle of the transmissive video projector body. In the present invention, the baffle is not recessed as in the conventional example, but protrudes from the baffle.

Similarly, by attaching an elevation angle to the speaker, the radiation angle (elevation angle) of the speaker can be freely changed according to the listening position, so that the central axis (AXIS) of the speaker is aligned with the viewer's ear. Configure.

[0017]

[Effect] By installing the speaker with an elevation angle of α, the radiation angle also shifts by α, which reduces the radiation power toward the floor, and also shifts the position of reflection, which reduces the amount of sound waves reflected on the floor. decrease.

As a result, the interference of reflected waves directly from the speaker to the waves is reduced, and by giving the speaker an elevation angle, the central axis of the speaker's radiation (AX
IS) can be adjusted to the position of the viewer's ears, and as a result, more direct wave components from the speaker are propagated to the viewer, resulting in highly clear audio.

Furthermore, a sub-baffle separate from the baffle of the main body of the transmissive video projector or a part of the speaker cabinet is connected to the fulcrum of the structure so that the angle of elevation can be freely changed. Then, by changing the elevation angle α in accordance with the viewing distance d and aligning the central axis of radiation of the speaker (AXIS) with the position of the viewer's ear, it is possible to obtain sound with even higher clarity.

[0020]

[Example] <Example 1> Hereinafter, an example of the present invention is shown in FIG.
This is explained by In Figure 1, 1 is the main body of the transmissive video projector, 2 is the projection tube, 3 is the lens group, 4 is the reflector, 5 is the screen, 6 is the speaker, 7 is the baffle to which the speaker is attached, and 8 is the installation of the transmissive video projector. This is the floor of the room where the

What is important here is that the baffle 7 to which the speaker is attached is configured to have an elevation angle α with respect to the floor 8 of the room in which the transmissive video projector 1 is installed.

As a result, as shown in FIG. 2, among the reflected waves 11a, 11b, 11c, . . . from the floor surface 8, the reflected waves 11b, 11c, . . . By increasing the height of viewer 9's ears, H
Since it passes through a lower position, the rate of interference with the direct sound 10 is reduced.

As a result, as shown in FIG. 3, the sound pressure frequency characteristic (d) is significantly flattened and the clarity is improved compared to the conventional sound pressure frequency characteristic (b).

On the other hand, FIGS. 4(A), 4(B), and 4(C) are contour diagrams of sound intensity in the range of height h=1 m and distance d=2 m in front of the transmissive video projector 1. It is. Figure 4(A) shows the speaker 6 as in the conventional case.
When the is mounted perpendicular to the floor 8, Fig. 4(B) shows the elevation angle α=7.5 degrees, and Fig. 4(C) shows the elevation angle α=15 degrees.
The cases shown are as follows:

It can be seen that as the elevation angle α becomes larger, a range of equal intensity levels can be obtained over a longer viewing distance d. Further, FIG. 4 shows that the smaller the number of contours (contour lines) 12, the more uniform the sound pressure level is obtained.

This means that it is better to install the speaker 6 with an elevation angle α, and that an appropriate viewing range can be obtained even if the viewing distance d from the transmissive video projector 1 to the viewer 9 becomes large. There is.

From this, it can be seen that the larger the screen (the larger the screen 5), the larger the appropriate clear viewing distance d is required, so it is advantageous for the mounting angle of the speaker 6 to have an elevation angle α. I understand.

Furthermore, in the case of a multi-way speaker system using a woofer, a midrange, a tweeter, etc., if the baffle is configured vertically and the midrange and tweeter are mounted above the woofer, as in the conventional example, the radiation from the woofer is The sound waves radiated from the midrange and the tweeters reach the viewer 9 later than the sound waves radiated from the tweeter, causing time distortion, which has the disadvantage of being caused, but there is also the advantage that it can be corrected by adding an elevation angle.

The structure of the present invention can also be applied to the case where speakers are incorporated into the stand of a direct-view television set that uses a cathode ray tube as a direct display.

Embodiment 2 In Embodiment 1, in order to give the mounting angle of the speaker 6 an elevation angle α, the entire baffle 7 to which the speaker 6 is mounted is configured to have an angle (elevation angle). However, as described in the description of the conventional example, it is easier to assemble and the manufacturing cost is lower if the structure is constructed using a plurality of rectangular members cut in parallel or at right angles from wood.

Therefore, in this embodiment, as shown in FIG. 5, the speaker 6 is attached to the baffle 7a configured vertically as in the conventional example, and a separate sub-baffle 13 having an elevation angle α. so that it is installed on the At this time, it is preferable to provide a round hole or a square hole 14 at a location corresponding to the mounting position of the loudspeaker 6 of the baffle 7a.

Further, if a closed system is desired, the hole 14 may not be provided.

The effect is similar to that of the first embodiment.

Embodiment 3 In Embodiments 1 and 2, once the elevation angle α of the baffle 7 or sub-baffle 7a is determined, it cannot be changed, resulting in a drawback that the optimum viewing distance d is fixed. Therefore, as shown in FIG. 6, a sub-baffle 15 is provided, and the top of this sub-baffle 14 is connected to the baffle 7a by a fulcrum 16 of a movable structure such as a hinge, so that the elevation angle α can be changed.

As a result, since the elevation angle α can be freely adjusted depending on the viewing distance d, clearer audio can be obtained.

Furthermore, a flange 1 is provided at the bottom of the sub-baffle 15.
If the baffle 5a is provided and configured to increase the degree of sealing with the baffle 7a, the bass sound will not be impaired.

Similarly, as shown in FIG. 7, a separate cabinet 17 housing the speaker 6 is provided, and the top of this cabinet 17 is attached to a fulcrum 16 of a movable structure such as a hinge.
If it is configured to be combined with the sub-baffle 7a,
Bass characteristics can be controlled.

[0038]

[Effects of the Invention] Since the present invention is constructed as described above, the following effects can be obtained.

[0039] By setting the elevation angle to the mounting angle of the speaker, the amount of sound waves deviated from the axis of the speaker that are radiated to the floor surface is reduced, so the reflected sound component that is reflected from the floor surface and propagated to the viewer is reduced. decreases, and the direct sound from the speaker is propagated to the viewer by that much more. As a result, the interference of the sound reflected from the floor with the direct sound from the speakers is reduced.
Clear sound can be obtained because the sound pressure frequency characteristics are flattened.

On the other hand, in a multi-way system using a woofer, midrange, tweeter, etc., the arrival time of the sound waves from each speaker to the viewer coincides due to the elevation angle, eliminating time distortion and providing clear and faithful sound. You can get a good sound.

[0041] Furthermore, by mounting the speaker on a separate sub-baffle or cabinet independent of the baffle,
If the sub-baffle or the top of the cabinet is connected using a movable fulcrum such as a hinge, the elevation angle of the sub-baffle or cabinet can be adjusted appropriately depending on the viewing distance, resulting in even clearer sound.

[Brief explanation of the drawing]

FIG. 1 is a structural cross-sectional view showing one embodiment of the present invention;

[Figure 2]
An explanatory diagram showing the effect of the present invention,

FIG. 3 is a sound pressure frequency characteristic diagram showing the effects of the conventional example and the present invention;

FIG. 4 is a characteristic diagram of sound intensity showing the effects of the conventional example and the present invention;

FIG. 5 is a structural sectional view showing another embodiment of the present invention;

[Figure 6
] Structural sectional view showing another embodiment of the present invention,

FIG. 7 is a structural sectional view showing another embodiment of the present invention;

FIG. 8 is a structural cross-sectional view and an explanatory diagram showing the propagation effect of sound waves in a conventional example;

[Fig. 9] Sound pressure frequency characteristic diagram in conventional example,

[Figure 10]
FIG. 2 is a structural cross-sectional view showing an improvement over a conventional example.

[Explanation of symbols]

1... Transparent video projector, 5... Screen,
6...Speaker, 7,7a...Baffle, 13
, 15... Sub baffle, 16... Fulcrum, 17... Cabinet 10... Direct wave, 11, 11a, 11
b...Reflected wave, 12...Contour (contour line).

Claims (6)

[Claims] 1. A speaker device for a transmissive video projector in which a speaker is disposed below a screen, wherein the speaker is mounted at an angle of elevation. 2. A speaker device for a transmissive video projector according to claim 1, wherein the elevation angle is 5 to 20 degrees. 3. The speaker device for a transmissive video projector according to claim 1, further comprising a sub-baffle to which the speaker is attached, the sub-baffle having an elevation angle. 4. The speaker device for a transmissive video projector according to claim 1, wherein the speaker is attached to a sub-baffle having an elevation angle different from that of the baffle, and is further fixed to the baffle. 5. According to claim 1, a baffle of a main body of a transmissive video projector and a separate sub-baffle independent from the baffle are provided, a part of the sub-baffle is coupled to the baffle by a fulcrum of a movable structure, and the A speaker device for a transmissive video projector in which the elevation angle of a sub-baffle can be freely changed. 6. According to claim 1, the speaker is mounted in a separate cabinet independent of the baffle, and the baffle and a part of the cabinet are connected by a fulcrum of a movable structure, so that the elevation angle of the cabinet can be freely changed. A speaker device for a transparent video projector.