JPH043695A - speaker system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a speaker system, and more particularly to a thin speaker system capable of reproducing deep bass sounds.

BACKGROUND OF THE INVENTION In recent years, there has been a strong demand for audio equipment that is small or thin and capable of high-fidelity reproduction because it takes up less space.

However, conventional speaker systems cannot reproduce deep bass unless they are equipped with a large-area diaphragm and a large-volume cabinet.

In view of this, the inventors first invented a speaker system that uses both a closed cabinet and an open-back cabinet on the same diaphragm.

This speaker system will be described below with reference to the drawings. FIG. 2 shows the configuration of a conventional speaker system. In the second session, (a) shows the plan view,
0)) shows a cross-sectional view taken along line A-A' in the same figure (a).

In FIG. 2(a), the diaphragm is removed to simplify the diagram. In FIG. 2, reference numeral 1 denotes a diaphragm, which is attached to a cabinet 3 by an edge 2 and is driven by a voice coil 5 inserted into a magnetic gap of a magnetic circuit 4. Outer periphery 1a of diaphragm 1
A sealed cabinet 6 is configured on the back of the system, and the lowest resonant frequency f0 of the system is almost set by the weight M of the vibration system and the stiffness SB of the sealed cabinet. On the other hand, the back surface of the central portion 1b of the diaphragm is separated from the sealed portion by the middle plate 7, inner edge 8, and duct 9.10, forming an open-back cabinet.

The operation of the speaker system configured as above will be explained below.

FIG. 3 shows the frequency characteristics of this speaker system in an anechoic chamber, and the overall sound pressure level corresponds to the sum of the sound pressure levels of only the closed part and only of the open part.

Regarding the sealed part, since the area of the diaphragm is reduced by the open part, the F0 will be lower even with the same internal volume of the cabinet, which is advantageous for bass reproduction, but the small area will reduce the diaphragm area. The playback level will be lower. on the other hand,
Regarding the open section, the opposite phase sound radiated to the back of the diaphragm passes through the duct 9 and 10 and is radiated to the rear of the cabinet, but this is diffracted to the front and superimposed on the sound radiated to the front. If the path difference from the rear to the front is small, the phase difference between the front and rear sounds of low frequencies will be small, and the sounds will be canceled out.

On the other hand, in the middle range, there is less sound cancellation and the sound pressure level increases. By using a combination of closed and open cabinets in this way, a speaker system that has the characteristics of a closed type cabinet in the bass range and an open type cabinet in the midrange, and has a flat and high sound pressure level over a wide frequency range, is created. realizable.

Problems to be Solved by the Invention However, with the above configuration, sound is also radiated from the back of the speaker, so when it is mounted on a wall, the sound from the back passes through the wall and leaks into the outside room, so it is necessary to increase the sound insulation properties of the wall. Particularly at low frequencies, sufficient sound insulation cannot be achieved unless the walls are made thicker.

The present invention solves the above problems, and aims to provide a playback system that reduces the sound pressure radiated to the rear wall surface and achieves good sound playback.

ll! Means for Solving the Problems In order to achieve the above object, the present invention provides a bass reflex type cabinet on the back of the first part of the diaphragm, an open-back cabinet on the back of the second part, and This is a speaker system in which the open part and the radiation surface of the bass reflex port are placed in the same direction.

Function: With the above-described configuration, the present invention cancels out the sound emitted from the diaphragm in the open rear part with the opposite phase sound from the bass reflex port provided on the same emitting surface, reducing the sound pressure emitted to the wall surface at the back of the speaker system. and play good sound.

EXAMPLE An example of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the invention. In Figure 1, (a) is a plan view, and (b) is the B of the same figure (a).
-B' shows a sectional view. FIG. 1(a) shows the case where the diaphragm is removed to simplify the diagram. In FIG. 1, reference numeral 11 denotes a diaphragm, which is attached to the cabinet 13 by an edge 12 and is driven by a voice coil 15 inserted into a magnetic gap of a magnetic circuit 14. A bass reflex cabinet 16 is configured on the back side of the outer peripheral portion 11a of the diaphragm 11, and a bass reflex cabinet 16 is configured on the back side of the outer peripheral portion 11a of the diaphragm 11.
6 is formed on the same radiation surface as a rear-open cabinet duct, which will be described later, on the opposite side to the front surface of the diaphragm 11. The resonance of the bass reflex port is set near the reproduction low frequency of this speaker system. On the other hand, the back surface of the central portion 11b of the diaphragm is separated from the closed portion by the middle plate 17, inner edge 18, and ducts 19 and 20, forming an open-back cabinet.

The operation of the speaker system configured as above will be explained below.

To explain the operation of the above configuration, due to the vibration of the diaphragm 11, sound is radiated separately into the front side of the diaphragm, the rear open baffle duct 19, 20, and the bass reflex port 16. The sound radiated from the back of the diaphragm is in the opposite phase to the sound from the front, and is radiated at a rate corresponding to the division ratio of the diaphragm. On the other hand, since the resonance of the port is set near the reproduction low frequency, the bass reflex port 16 emits sound that is in phase with the front surface of the diaphragm, that is, in a phase opposite to that of the open cabinet ports 19 and 20. Since the bass reflex port 16 is provided on the same radiation surface as the rear open cabinet, the sound radiated from the bass reflex port 16 and the sound radiated from the rear open cabinet ports 19 and 20 cancel each other out, and this speaker system The sound emitted to the back is drastically reduced.

Effects of the Invention As described above, in the speaker system of the present invention, the sound pressure radiated to the back surface is reduced even when it is mounted on a wall surface, so that the sound does not pass through the back wall surface and leak out of the room. Therefore, good sound field reproduction can be achieved without increasing the thickness of the walls or improving the sound insulation properties.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a speaker system according to an embodiment of the present invention, FIG. 2 is a block diagram of a conventional speaker system, and FIG. 3 is a sound pressure frequency characteristic diagram of a conventional speaker system. 11... Vibration plate, 12... Edge, 1
3...cabis note, 14...magnetic circuit, 15...voice coil, 16...
Bass reflex port, 17...middle plate, 19.20.
·····duct. Name of agent: Patent attorney Shigetaka Awano Mimi Higogoshiba

Claims (1)

[Claims] A bass reflex type cabinet is provided on the back of the first part of the diaphragm, an open rear cabinet is provided on the back of the second part, and the open rear part and the radiation surface of the bass reflex port are provided in the same direction. speaker system.