JPH03147498A - Speaker system - Google Patents

Abstract

PURPOSE:To improve the reproduction efficiency of heavy low pitched sound and to reduce the change in a sound pressure frequency characteristic attended with the installing condition by constituting an acoustic circuit in a cabinet with a screen fitted thereto. CONSTITUTION:A screen 2 is stuck to the surface of a cabinet 1 and speaker units 3, 3' are fitted to the lower face of the cabinet 1. A sound duct is formed in the inside of the cabinet 1 and radiation sound to a diaphragm rear face radiates from ports 4, 4' through the sound duct. On the other hand, a high pitched sound signal is reproduced by tweeter systems 5, 5'. In the internal structure of the woofer system, parts 21, 21', 22, 22' and 23, 23' for left and right channels are formed symmetrical horizontally. Then the cross sectional area in the middle of the sound duct is increased more than that of a front and rear parts of the duct, then the middle part acts like an acoustic capacitor and a flat sound pressure frequency characteristic is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a speaker system, and more particularly to a speaker system for a projection system that is integrated with a screen for projecting images.

BACKGROUND OF THE INVENTION In recent years, audiovisual equipment has become larger in screen size, has higher image quality, and has become higher in sound quality. In particular, with the commercialization of liquid crystal projectors, it is expected that large screen systems of 70 inches or more will become popular in general households. Along with this, there is a strong demand for speaker systems to have high sound quality suitable for large screens, especially the ability to reproduce powerful deep bass sounds.

However, conventionally, even in large screen systems, a normal bookshelf type speaker system 7 is used as shown in FIG.
1.71' were simply placed on the left and right sides of the screen 72. Therefore, the inventors filed a patent application No. 62-223463 for a speaker system in which a screen is integrated with the diaphragm of a speaker and a cabinet that can be both closed and opened is provided on the back of the diaphragm.

The screen and diaphragm integrated speaker system will be described below with reference to the drawings.

FIG. 8(a) is a perspective view of the speaker system, and FIG. 8(b) is a perspective view of the speaker system.
) is a sectional view taken along line AA′ in FIG. 8(a) in the direction of the arrow. In Figure 8, 1 is the cabinet, 2 is 20
This is a diaphragm for a bass speaker that reproduces frequencies below 0Hz, and the surface is a screen. Reference numerals 5 and 5' denote left and right speakers for middle and high frequencies, and one speaker unit for middle ranges 6.6' and one unit for high ranges 7.7' are attached.

Figure 8 (b) shows a cross section of a bass speaker, where the diaphragm with a screen pasted on its surface is optimally placed.
It is driven by two voice coils (not shown). A closed cabinet 81 is formed on the back side of the periphery of the diaphragm, and an inner edge 82 is formed on the back side of the center part. The middle plate is separated from the closed part by a 83° port 84, making it an open-back cabinet.

Although the bass speaker configured as described above has a large area diaphragm, only the peripheral portion is a closed speaker, so the cabinet stiffness is small and the lowest resonant frequency can be lowered.

In addition, regarding the rear open section, the sound from the back of the diaphragm is radiated through the port 84 provided at the center of the back of the cabinet, so it is possible to create a large phase difference between the front and rear sounds, which is a problem with open speakers. It becomes possible to reduce the cancellation caused by the sound.

Problems to be Solved by the Invention However, the above configuration has the following problems.

1) Since the diaphragm is a large-area, one-piece object, it is heavy and the reproduced sound pressure level is low.

2) Therefore, a large driving force is required, and a large number of large magnets are used, which increases the cost.

3) Since the port is provided on the back of the cabinet,
It cannot be installed closely against a wall.

4) The sound pressure frequency characteristics change depending on the installation conditions, and especially when installed on a wall, the playback efficiency in the deep bass range decreases due to the influence of sound going around from the port.

The present invention solves the above-mentioned problems, and the purpose of the present invention is to effectively utilize the dead space behind the screen to improve the reproduction efficiency of deep bass sounds, and also to be able to install the screen in close contact with a wall surface. It is an object of the present invention to provide a speaker system whose sound pressure frequency characteristics change little depending on conditions.

Means for Solving the Problems In order to achieve the above object, the present invention provides a substantially rectangular parallelepiped cabinet and at least one cabinet attached to the cabinet.
It is equipped with a book speaker unit and a video projection screen attached to the cabinet.

Effect: With the above configuration, since the screen is attached to the cabinet, the dead space behind the screen can be used effectively as the volume of the cabinet. The screen is 70 inches in size and is large, approximately 1.5 mm, so even if the cabinet is only 10 cm thick, the internal volume of the cabinet is approximately 120! Therefore, it is possible to secure a volume comparable to that of a large speaker system. An acoustic circuit is configured inside the cabinet, but the system is not limited and may be a closed type, a bass reflex type, a horn type, etc.

EXAMPLE A first example of the present invention will be described below with reference to FIG. In Figure 1, 1 is a cabinet with dimensions of width 15Qcm, height 114cm, 5cm depth, and depth 10cm.
A 70 inch screen 2 is pasted on the 0 cm surface. Speaker units 3, 3' are 8cm x 25
This is a speaker unit with a square diaphragm of cm size and is attached to the bottom of the cabinet. A sound path is formed inside the cabinet, and the sound radiated to the rear surface of the diaphragm passes through the sound path and is radiated from port 4.4'. This screen-type speaker system reproduces bass frequencies below 200Hz. Frequencies of 200 Hz or more are reproduced by separate high-frequency speaker systems 5 and 5' provided on both the left and right sides. Since these speakers are for high sound, they do not require a large cabinet volume.The width is 12C1, the height and depth are the same as bass speakers, and the internal volume is small, about 81 cm.

Next, the internal structure of the bass speaker system will be explained with reference to FIG. FIG. 2 shows the main parts of the internal structure. The interior is symmetrical, and the left and right channels of stereo signals are input respectively. Each consists of three main parts. The first part 21.21' has a cross-sectional area of 3C+5X181 and a length of 60 cm, the second part 22.22' has a cross-sectional area of 8C The sound radiated to the back of the speaker unit passes through the first, second and third parts and is radiated from the port. It is disclosed in Japanese Patent No. 63-243022.That is, by making the cross-sectional area of the central part of the sound path larger than that of the front and back,
The central portion acts as an acoustic capacitor, suppressing the peak of the sound pressure frequency characteristic that occurs at the high sound limit frequency of the reproduction band, and realizing a flat sound pressure frequency characteristic.

As described above, according to this embodiment, the dead space behind the screen can be effectively used as a speaker cabinet, and by configuring an internal acoustic circuit that is optimal for deep bass reproduction, the low frequency range is highly efficient and flat. This makes possible sound reproduction. Furthermore, since there are no ports on the back of the cabinet, it can be installed closely against a wall. Furthermore, when installed on a wall, the baffle effect enables even more efficient regeneration. Note that since bass sounds have little sense of direction, it is possible to use an integrated speaker unit instead of a two-channel stereo configuration.

Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, the treble speakers 7.7' are incorporated in the same cabinet. Note that the midrange speaker was omitted, resulting in a two-way system. Furthermore, bass speakers 3, 3' and ports 4, 4' are also provided on the lower front surface of the screen.

The configuration of the acoustic circuit inside the cabinet is the same as in the first embodiment.

In the first embodiment, the bass speaker and port were installed at the bottom of the cabinet, so if the speaker system was installed embedded in the wall, a space was required at the bottom. Because there is no need for such a space,
Fits perfectly into a wall opening. It can also be used directly on a stand. Note that the treble speaker may not be integrated, but may be provided separately, or the center channel speaker may be integrated.

Next, a third embodiment of the present invention will be described with reference to FIG. 4. In this embodiment, high-pitched and low-pitched speakers and ports are arranged on the left and right sides of the cabinet. Therefore, compared to the second embodiment, the separation between the left and right sounds becomes clearer, and the sound image is no longer biased toward the bottom.

In addition, as shown in Figure 5, it is okay to separate the bass speaker and treble speaker and install the bass speaker unit and port on the left and right sides of the cabinet. It can be used as a woofer and combined with an existing speaker system.

Next, a fourth embodiment of the present invention will be described with reference to FIG. In this embodiment, the left and right speaker systems are 1,1'
and are connected together by a connecting fitting 8,
The screen 2 pasted on the panel was attached after the speakers were installed. In other embodiments, the screen was integrated into the cabinet from the beginning, so the bass speaker system alone weighed about 6.5 lbs.
It became a 0 temple, and could not be set up or moved by humans.

In this embodiment, by separating the left and right parts, even a second person can install and move it. It can also be used in combination with an existing roll screen or the like as a screen, and it can also be used in combination with a large screen of 70 inches or more by installing the left and right speaker systems apart.

Effects of the Invention As explained in detail with reference to the embodiments above, the present invention has the following effects:
The speaker unit is attached to the cabinet with the screen attached, and the acoustic circuit is configured inside the cabinet, so by effectively utilizing the dead space behind the screen and using it as a speaker cabinet, powerful bass reproduction is possible. Furthermore, the speaker can be used in close contact with a wall or embedded. In addition, the change in sound pressure frequency characteristics due to installation conditions is small, and when it is installed close to a wall, the baffle effect improves bass reproduction efficiency.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the first embodiment of the present invention, and FIG. 2 is a perspective view of the first embodiment of the present invention.
3 is a perspective view of the second embodiment of the present invention, FIG. 4 is a perspective view of the third embodiment of the present invention, and FIG. 5 is a perspective view of the third embodiment of the present invention. FIG. 6 is a perspective view of the treble speaker system separately installed in the embodiment, and FIG.
...Screen, 3.3'...Bass speaker unit, 4.4'...Port, 5,5'...
...Middle and high range speaker system, 6.6'...
・Medium sound speaker unit, 7.7′...Treble sound speaker unit, 21.21”, 22.23
゜23'... Sound road.

Claims (8)

[Claims] (1) A speaker consisting of a substantially rectangular parallelepiped cabinet, an image projection screen provided on one surface of the cabinet, and at least one speaker unit attached to a surface of the cabinet other than the surface on which the screen is provided. system. (2) Claim comprising: at least one port provided on a portion of the cabinet other than the screen; and a sound path connecting the rear surface of a diaphragm of a speaker unit provided inside the cabinet and the port. 1) The speaker system described. (3) The speaker system according to claim 1 or 2, wherein at least one of the speaker unit and the port is provided on the lower surface of the cabinet. (4) At least one of the speaker unit and the port is
3. The speaker system according to claim 1, wherein the speaker system is provided at a lower part of the screen on a surface of the cabinet where the screen is provided. (5) Claim (1) or (2) characterized in that at least one of the speaker unit and the port is provided on one or both sides of the screen on the front surface of the cabinet.
Speaker system as described. (6) The speaker system according to claim (1) or (2), wherein at least one of the speaker unit and the port is provided on a side surface of the cabinet. (7) A speaker system comprising a plurality of cabinets, a removable screen integrally attached to the plurality of cabinets, and at least one speaker unit attached to the plurality of cabinets in a portion other than the screen portion. . (8) The sound path formed by connecting the rear surface of the diaphragm of the speaker unit and the port is composed of three parts, and among these three sound paths, the first part on the speaker unit side and the third part on the port side The cross-sectional area of the part is S_1, the cross-sectional area of the second part in the center is S_2, the length is l_2, and the total length of the sound path is l
When _1, 2≦S_2/S_1≦5, 0.2≦l_
Claim (1) characterized in that 2/l_1,≦0.8.
) to (7).