JPS6333431Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a structure near the woofer for improving the sound pressure frequency characteristics of a multi-way speaker system that uses a cone-shaped speaker (referred to as a woofer) for bass sounds.

Conventionally, in a multi-way speaker system in which multiple speakers with different reproduction bands are mounted on the same butt-full board, when the woofer responsible for bass reproduction is cone-shaped, a woofer with dimensions substantially the same as the wavelength of the reproduced sound waves is used. A conical depression exists on the butt-full surface, and the resonance of the depression causes large undulations in the frequency response near the upper limit of the woofer's band and in the midrange, which is shared by the squawker. In the sound range, interference between reflected waves and direct waves due to disturbances in the reflection of sound waves at hollows can cause peaks and dips in the frequency characteristics, which can impair hearing. In order to eliminate this negative effect on frequency characteristics, it has been adopted to make the speaker's diaphragm flat, but this method results in split vibration due to the lack of rigidity of the flat diaphragm, which causes the frequency characteristics to deteriorate. Moreover, in order to increase the rigidity, the mass increases, which reduces efficiency, and the speaker becomes extremely expensive.

This idea improves sound pressure frequency characteristics in a speaker system that incorporates a woofer that uses a conventionally used lightweight, highly rigid, and inexpensive cone diaphragm by eliminating the effects of the depressions of the cone diaphragm. This is about a speaker system that
The structure will be explained below with reference to the drawings.

Figures 1a and 1b are a perspective view and a sectional view showing the structure of Embodiment 1 of the present invention in a 3-way speaker system as an example, where 1 is a butt-full plate of the speaker system, 2 is a cone-shaped woofer, and 3 is a midrange sound range. 4 is a squawker for reproduction, 4 is a tweeter for high frequency reproduction, and 5 is a shielding plate which is the main point of the present invention. be installed so that The area of the shielding plate 5 is 55% to 85% of the opening area of the opposing woofer.
% is desirable. If the area of the shielding plate 5 is larger than this, the area of the sound emitting slit 6 will become smaller and efficiency will not only decrease, but also the space 7 between the shielding plate and the cone diaphragm will act as stiffness, which will affect the frequency characteristics of the bass range. changes. Moreover, if the area of the shielding plate 5 is smaller than the above range, the sound emitting slit 6
As the size of the sound emitting slit 6 increases, in high frequencies having wavelengths shorter than this size, the effect of the space of the sound emitting slit 6 appears, reducing the effect of the shielding plate and deteriorating the frequency characteristics. By employing this shielding plate 5, the sound waves emitted from the squawker 3 and tweeter 4 have wavelengths longer than the dimensions of the sound emitting slit 6 in the main band, so they are not affected by the sound emitting slit or the depression inside it. Since the light acts as if it were reflected from a flat buffed plate, no deterioration of frequency characteristics occurs.

In addition, since this shielding plate does not vibrate like a woofer diaphragm or the above-mentioned flat plate diaphragm, cross-modulation distortion due to low frequency frequencies that occurs in conventional speaker systems does not occur, and a speaker system with excellent audibility can be obtained. I can do it.

FIG. 2 is a sectional view of a main part of a second embodiment of the present invention, in which a conical body 8 is used as a shielding plate. The conical body is attached so that its bottom surface is on the same plane as the buttful plate 1 and its top faces toward the diaphragm. The area of the bottom surface takes the above-mentioned ratio to the woofer opening.

In addition to the same effects as in the first embodiment, the shape of the space 7 is made irregular in the direction of the main axis of the woofer, thereby reducing standing waves inside.

FIG. 3 is a sectional view of a main part of Example 3 of the present invention. In this embodiment, the shielding plate has an annular shape, and the area of the annular portion surrounded by the outer periphery and the inner periphery is in the above-mentioned ratio to the area of the woofer opening, and the dimensions of the hole 6' in the center are The circumferential slit 6 is attached so that its front surface is flush with the baffle plate and has the same radial dimension as the peripheral slit 6.

As in Examples 1 and 2, it acts in the same way as a flat buttful plate in the middle and high frequency ranges to prevent deterioration of frequency characteristics, and further reduces the internal pressure of the space 7 to reduce the output level in the low frequency range. It has the effect of preventing

FIG. 4 and FIG. 5 are both frequency characteristic diagrams showing the effects of the first embodiment of the present invention. FIG. 4 shows the frequency characteristics of the squawker, where 41 shows the sound pressure frequency characteristics when a shielding plate is attached and 42 shows the sound pressure frequency characteristics when there is no shielding plate. 400 if there is no shielding plate
There are undulations in the frequency characteristics in the band from Hz to 800Hz, but these undulations disappear by installing the shielding plate, and the squawker's original frequency characteristics are the same as when there are no depressions on the buttful surface. . Also, Figure 5 shows the frequency characteristics of the tweeter.
1 is the sound pressure frequency characteristic when the shielding plate is attached, and 52 is the sound pressure frequency characteristic when the shielding plate is not installed. If there is no shielding plate, many peaks and dips can be seen in the band from 2KHz to 8KHz due to interference between the reflected wave from the recessed surface of the woofer and the direct wave, but by installing the shielding plate, these peaks and dips can be seen. The dip has largely disappeared and the frequency characteristics are the same as the tweeter's original, indicating that the use of a shield plate is extremely effective in improving the frequency characteristics, including in the case of squawkers.

In addition, the material for these shielding plates has a porosity of 30 to 50%.
By using a porous material in the foam region, the frequency response can be made even more flat due to its sound absorption properties. When the porosity of the foam exceeds 50%, the acoustic transmittance increases and the effect as a shielding plate decreases. When the porosity is less than 30%, the sound absorption coefficient decreases and the effect of using the foam is no longer recognized. As the foam material, foamed ceramic, foamed metal, foamed resin, etc. can be used.

As stated above, the present invention has a cone-type woofer with a diaphragm that has a 55 to 85% area in front of its diaphragm.
By installing a shielding plate having an area of This is intended to prevent the deterioration of sound pressure frequency characteristics caused by this, and it is possible to obtain high-fidelity music reproduction without unnatural coloring of the reproduced tone.

[Brief explanation of drawings]

1a and 1b are perspective views and sectional views of the speaker system of the present invention according to the first embodiment, FIG. 2 is a sectional view of the main parts of the second embodiment, FIG. 3 is a sectional view of the main parts of the third embodiment, and FIG. is a frequency characteristic diagram of the squawker of the first embodiment, and FIG. 5 is a frequency characteristic diagram of the tweeter of the first embodiment. Reference numeral 1 designates a baffle plate of the cabinet, 2 a cone-shaped woofer, 3 a squawker, 4 a tweeter, 5 a shielding plate, 6 a sound emitting slit portion around the shielding plate, and 7 a space between the shielding plate and the cone.

Claims (1)

[Claims for Utility Model Registration] 1. In a speaker system in which a plurality of speakers with different playback bands are mounted on the same butt-full surface 1, in front of the diaphragm of the bass cone-shaped speaker 2, there is a spacer with an opening area of the bass speaker. 55%~85
% of the front surface of the shielding plate 5 is mounted on the same plane as the buff-full surface. 2. The speaker system according to claim 1, wherein the shielding plate 5 is made of foam. 3. The speaker system according to claim 2, wherein the foam has a porosity of 30 to 55%.