JPH0242897A - Acoustic reproducting device for video - Google Patents

Abstract

PURPOSE:To obtain the same acoustic effect as a theater in a video projection system by composing the center channel loudspeaker systems of total four sets to be provided on both sides of a screen and on upper and lower sides of the screen center in one set, respectively. CONSTITUTION:Left and right channel loudspeaker systems 3 and 4 are disposed on both sides of a projection screen 8, and simultaneously, four sets of center channel loudspeaker systems 5a, 5b, 5c and 5d are disposed on left and right both sides of the picture 8 and on the upper and lower side of the center of the picture 8. Consequently, by the loudspeaker systems 5a-5d, center channel signals are regenerated from the upper, lower, right and left sides of the screen 8. In such a manner, the voice of the center channel is normally positioned, a sound image normal position is made clear, and a proper sound field balanced to the size of the screen can be prepared.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a video audio reproduction device that reproduces a stereo audio signal accompanying an image signal displayed on a screen.
In particular, it relates to the improvement of sound field sensorineural image localization.

[Prior Art] Fig. 3 is a plan view of a movie theater generally known as a video and audio reproduction device using a large screen, and Fig. 4 is a front view of its projection screen. (1) is a movie theater including audience seats, (2) is a screen, (3) is a left channel speaker system, (4) is a right channel speaker system, (5) is a center channel speaker system, and (6) is a projection screen. It is a room.

FIG. 5 is a plan view showing a typical installation example of a conventional video projection system that has been put into practical use in recent years; in the figure, (3) is a left channel speaker system, (4) is a right channel speaker system, (7
) is a room with a video projection system installed,
(8) is a video projection screen, (9)
is the main body of the projector.

In the movie theater (1), the 2-channel audio signal prepared for the movie film is decoded by the Dolby surround system, and the center channel signal is extracted and supplied to the center channel speaker system (5). Screen with high audio transparency (
2), the left channel speaker system (3) and the right channel speaker system (4)
Since the center channel speaker system (5) can be installed behind the screen, the audience can feel as if the sound is coming from the screen, and there is no sense of discomfort in the sound field or sound image with the screen. You can enjoy video and audio playback without feeling any discomfort. However, in the large-scale video projection systems that have been put into practical use in recent years, the amount of projected photoelectricity is very small compared to that of movies, so a dedicated screen for video projectors with good reflectivity (
8) is used, but since this screen (8) has low sound transparency, it is impossible to install each speaker system behind the screen like in a movie theater (1), and the 5th screen is used.
As shown in the figure, the left and right channel speaker systems were often installed on both sides of the screen, and the center channel speaker system was often omitted.

[Problems to be Solved by the Invention] In this video projection system, the left and right channel speakers are installed on both sides of the video projection screen, so the sound field becomes too large compared to the screen size. Problems include the sense that the sound is coming from outside the screen, and the sound image localization at the center of the screen is worsened by the wide distance between the left and right speakers, resulting in sound playback that seems out of focus. was there.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a video sound reproduction device that can obtain the same sound effects as in a movie theater in a video projection system.

[Means for Solving the Problems] A video audio reproduction device according to the present invention has left and right channel speaker systems disposed on both sides of a video screen, and
Four center channel speaker systems are placed on both sides of the video screen and above and below the center of the screen.

[Function] This invention is applied to the video and audio reproduction device, 4
The center channel speaker system of the unit reproduces the center channel signal from the top, bottom, left and right of the screen, so the center channel audio is localized within the screen, and the sound image is clearly localized, making it suitable for the size of the screen. A sound field is created.

[Embodiments of the invention] An embodiment of the present invention will be described below.

Fig. 1 is a plan view of a room in which a video projection system according to an embodiment of the present invention is installed, and Fig. 2 is a front view of the room on the screen side. system, (4) is the right channel speaker system, (7) is the room where the video projection system is installed, (8) is the video projection screen, and (9) is the projector itself. Similar to the example, (5a) is a center channel speaker system installed on the left side of the screen (8), (5b) is a center channel speaker system installed on the right side of the screen (8),
(5c) L:! A center channel speaker system is installed at the upper center of the screen (8), and (5d) is a center channel speaker system installed at the lower center of the screen (8).

First, left and right channel speaker system (3), (
4) and center channel speaker system (5) on both sides.
If only a) and (5b) are added, these center channel speaker systems (5a) and (5b) emit the same sound from both sides of the screen (8), so only left and right channel speaker systems (3) and (4) are added. Compared to the case of playback, this has the effect of limiting an overly expansive sound field. However, in a configuration in which only the two center channel speaker systems (5a) and (5b) are added, the sound image localization within the screen is improved compared to when only the left and right channel speaker systems (3) and (4) are used. A sound image that is slightly wavy to the left and right is localized, and the sound image becomes horizontally elongated relative to the image on the screen.

Next, the left and right channel speaker systems (3), (4
), by adding only the center channel speaker systems (5c) and (5d) above and below the center of the screen, the sound image localization at the center of the screen is considerably improved and the sound field restriction effect is also large, but
Since the center channel speakers (5c) (5d) are located above and below, they are vertically elongated with respect to the image on the screen.

By combining the above two examples, there will be 4
center channel speaker system (5a), (
If 5b), (5c), and (5d) are arranged respectively, the localization and size of the sound image will be greatly improved, and a natural sense of unity with the image similar to that felt in a movie theater can be achieved. .

Furthermore, if the viewer is not in front of the center of the screen but off to one side, the sound image moves in a direction away from the center line. 5b) can be improved by forcibly directing the directional characteristic pattern inward and adjusting the sound balance of the center channel speaker systems (5a) and (5b).

Also, since the viewer is located somewhat below the vertical center line of the screen, such as when sitting on a chair, the effect of the center channel speaker system (5c) at the top center of the screen can be increased by pointing it slightly downward. can be done.

In addition, the size of the screen and the relationship between its installed position and the viewer's position vary widely.
Left and right center channel speaker system (5a)
(sb) and the upper and lower center channel speaker systems (5c) (5d) by changing the impedance of the speaker system.

It is possible to make it variable by inserting an attenuator.

In addition, although the above embodiment was explained as a video audio reproduction device in a projection type video projection system,
Similar effects can also be obtained in televisions with direct-view cathode ray tubes or rear projection systems in which the speaker system cannot be positioned behind the screen.

[Effects of the Invention] As described above, the video audio reproduction device of the present invention has four center channel speaker systems, one each on both sides of the screen and one on the top and bottom of the center of the screen.
A video projection system also has the effect of obtaining good sound field sensor sound image localization similar to that of a movie theater.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a room in which a video projection system according to an embodiment of the present invention is installed, FIG. 2 is a front view of the screen side, FIG. 3 is a plan view of a conventional movie theater, and FIG.
The figure is a front view of its projection screen, and FIG. 5 is a plan view of a typical installation example of a conventional video projection system. In the figure, (3) is the left channel speaker system, (4) is the right channel speaker system, and (5) is the right channel speaker system.
, (5a), (5b), (5c), (5d
) is a room with a center channel speaker system, (7) is a room with a video projection system, (8)
is a video screen (screen for video projection),
(9) is the main body of the projector. The same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] In a video audio reproduction device in which a left channel speaker system and a right channel speaker system are arranged on the left and right sides of a video screen, respectively, four speaker systems are provided with a center channel audio signal extracted from both left and right channel audio signals. A video sound reproducing device characterized in that it is disposed on both left and right sides of the video screen and above and below the center of the screen.