JPH03192999A - Speaker device - Google Patents

Abstract

PURPOSE:To reduce phase distortion and to improve the fixed position of an acoustic image by arranging the opening parts of both ends of a port formed unitedly with a buffle plate or a cabinet on different axes, and making the areas of these opening parts of both ends larger than the minimum sectional area of the inside part of the port. CONSTITUTION:The port 12 is formed unitedly with the buffle plate 11 by resin molding. Since the port 12 is constituted so that the area of the outside opening part 13 is largest, and its sectional area inside its tube becomes smaller towards the innermost recess of the port 12, a minimum sectional area part 14 is formed at the innermost recess of the port 12. The port 12 is constituted so that an inside opening part 15 larger than this minimum sectional area in its area is formed at the bottom of the innermost recess. Thus, since the opening parts 13, 15 at both ends of the port 12 are arranged on the different axes, and in addition, the areas of both opening parts 13, 15 are made larger than the minimum sectional area of the inside of the port 12, the phase distortion can be reduced, and the fixed position of the acoustic image can be made excellent.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a speaker device used in television receivers, automobiles, and various audio equipment.

2. Description of the Related Art In recent years, the number of speaker devices using enclosures made of resin moldings has rapidly increased, especially for speaker devices used in television receivers.

A conventional speaker device will be explained below.

FIG. 6 is a perspective view showing the schematic structure of a conventional phase inversion type speaker device. In FIG. 6, 1 is a baffle plate, and a port 2 is integrally formed by resin molding. A speaker 3 is attached to a baffle plate 1, and this baffle plate 1 is fitted and connected to a cabinet 4. Also, since the port 2 is integrally molded with the baffle plate 1 by resin molding, the port 2 is molded integrally with the baffle plate 1, so due to the draft angle of the mold,
The area AO of the outer opening 6 is the area A1 of the inner opening 6.
Become bigger. In other words, the structure was such that Ao>mui.

The operation of the speaker device configured as described above will be described below.

Here is the Helmholtz co-location of the box with port 2.
l is the equivalent image mass of port 2 and the equivalent stiffness of the box. The sound emitted from the front of the diaphragm of speaker 3 and the sound emitted from the back are in opposite phase, but among the sounds emitted from the back of the diaphragm, the sound with frequency components higher than the resonance frequency f'ob is transmitted to the port 2, the phase is reversed. Since this sound is synthesized with the sound from the front of the diaphragm of the speaker 3, the low-range reproduction limit frequency can be lowered compared to a closed box with the same internal volume.

Next, we will focus on the inflow and outflow of air at port 2. First, when an input signal is applied to the speaker 3 and the diaphragm moves backward, the pressure inside the box increases, and air flows out from the inside of the box to the outside through the port 2. That is, air flows from the inner opening 6 of the port 2 toward the outer opening 6. Conversely, when the diaphragm moves forward, the pressure inside the box decreases, so air flows from the outer opening 6 of the port 2 toward the inner opening 6.

Problems to be Solved by the Invention When air flows into port 2 with the above configuration, the air flow direction suddenly changes, causing the air to separate from the inner surface immediately behind port 2, causing contraction, and after a while, the air flows into port 2. 2 is satisfied and flows. It is generally known in fluid mechanics that energy loss at this time occurs when the airflow velocity decreases, and is proportional to the square of the velocity difference before and after the decrease. The above situation is shown in Figs. 7 and 8@8. FIG. 7 is a sectional view showing how air 7 flows in through the inner opening 6 of the port 2. Port 2 formed in baffle plate 1 in FIG.
When air 7 flows into the inner opening 6, a peeling area 8 is generated immediately after the inner opening 6, as described above. FIG. 8 is a sectional view showing how air 9 flows in through the outer opening 6 of the port 2.

Similarly, in FIG. 8, a peeling area 10 is formed immediately after the outer opening 5 of the port 2.

However, in the conventional configuration described above, the area A of the outer opening 6
0 and the area Ai of the inner opening 6 are different, so the energy loss in both these openings is different. In other words, there is a problem in that phase distortion occurs in that the sound when the diaphragm of the speaker 3 moves forward is different from the sound when the diaphragm moves backward.

Further, since the outer opening 5 and the inner opening 6 of the port 2 are on the same axis, the sound radiated from the back surface of the diaphragm of the speaker 3 can easily pass through the port 2.

In other words, a large amount of middle and high frequency components of the sound radiated from the back surface of the diaphragm exit through the port 2, resulting in a double sound source, resulting in poor localization of the sound image.

The present invention solves the above-mentioned conventional problems, and aims to provide a phase inversion type speaker device with less phase distortion and good localization of sound images.

Means for Solving the Problems In order to solve this problem, the speaker device of the present invention has the openings at both ends of a port molded integrally with a panful plate or cabinet made of a resin molded product arranged on different axes. Moreover, the area of both openings is larger than the minimum cross-sectional area within the port pipe.

Effect: With this configuration, it is possible to reduce the difference between the area mu 0 of the outer opening of the port and the area mu i of the inner opening, so the difference in peeling areas that occur immediately after the openings on both sides is also reduced.
The difference in energy loss can also be reduced.

It is possible to extremely reduce distortion and phase distortion.

Also, since the openings on both sides are placed on different axes, the air passing through the port will change direction once. For this reason, among the sounds emitted from the back of the speaker's diaphragm, mid-high range sounds with short wavelengths are significantly attenuated by passing through the ports, so almost no mid-high range sounds are radiated from the ports. In other words, the sound in the middle and high ranges is only the sound radiated from the front of the speaker's diaphragm, so the sound image is localized.

EXAMPLE An example of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing the structure of a port of a speaker device in a first embodiment of the present invention.

In FIG. 1, a port 12 is formed integrally with a baffle plate 11 by resin molding. The area of the outer opening 13 of the boat 12 is limited due to the draft angle of the 12-port resin mold. is the largest (as you move towards the back of boat 12,
Since the cross-sectional area within the tube is small, a minimum cross-sectional area portion 14 is formed deep inside the port 12. In this structure, an inner opening 15 having an area larger than this minimum cross-sectional area is provided on the bottom surface at the back of the port 12. FIG. 2 is a perspective view showing a schematic structure of a speaker device according to a first embodiment of the present invention having the port 12. As shown in FIG.

In FIG. 2, reference numeral 11 denotes a baffle plate on which the port 12 described above is integrally formed. Speaker 1 is installed on baffle plate 11.
6 is attached, and the cabinet 17 is fitted and connected to the baffle plate 11.

The operation of the speaker device configured as described above will be explained below. As explained in the conventional example, port 1
When the sound with a frequency component higher than the resonant frequency of the helm of the box with 2 passes through the port 12, its phase is reversed and is synthesized with the sound from the front of the diaphragm of the speaker 16. The low-frequency reproduction limit frequency can be lowered compared to a box. Furthermore, the air inflow and outflow at the port 12 is the same as described in the conventional example, but since the difference between the area Ao of the outer opening 13 and the area Mu i of the inner opening 16 is small, peeling occurs at both openings. The area will be approximately the same, and the energy loss will also be approximately the same. In other words, phase distortion becomes extremely small. Furthermore, the sound emitted from the back surface of the diaphragm of the speaker 16 passes through the inner opening 16 and is emitted from the outer opening 13, but since the pass is bent, the sound in the middle and high ranges is significantly attenuated.

That is, the sound in the middle and high ranges is only the sound from the front of the diaphragm of the speaker, so the sound image is localized.

As described above, according to this embodiment, by arranging the openings at both ends of the port 120 on different axes and making the area of both openings larger than the minimum cross-sectional area inside the port, phase distortion is extremely reduced. , it is possible to achieve excellent localization of the sound image.

A second embodiment of the present invention will be described below with reference to the drawings. FIG. 3 is a structural sectional view of a speaker device showing a second embodiment of the present invention. In FIG. 3, a port 12 similar to that described in the first embodiment of the present invention is formed in the panful plate 11, and a speaker 1673E is attached thereto. A rear port 19 is integrally formed on the gear vignette 18 and is fitted and connected to the baffle plate 11.

Moreover, a partition plate 21 having an internal port 20 is interposed inside the box, and the inside of the box is divided into a first chamber 22 and a second chamber 23.
The internal port 20 connects both chambers. That is, it is a double bass reflex type speaker device, and is equipped with a port 12 on the front and a port 19 on the back.

The operation of the speaker device configured as described above will be explained below. First, if we focus on chamber 22,
Similar to a normal phase-inverting speaker device, sounds with frequency components higher than the Helmholtz resonance frequency determined by the internal volume of the first chamber 22 and the internal port 20 are radiated from the port 12 and the rear port 19 with the phase inverted. . Next, the -
We will focus on the combined volume of the chamber 22 and the second chamber 23, the port 12, and the back port 19. This is also similar to a normal phase inversion type speaker device, and the sound with a frequency component higher than the Helmholtz resonance frequency defined by the synthesis volume and the synthesis port is emitted with the phase inverted.

These sounds and the sound emitted from the front of the diaphragm of the speaker 16 are synthesized.

Next, the inflow and outflow of air will be explained. First, port 1
The flow and inflow of air in step 2 is the same as that described in the first embodiment, so a description thereof will be omitted. Next, internal port 20
Since the upper and lower aperture areas are the same, no phase distortion occurs. However, regarding the rear port 19, the phase distortion that occurs there cannot be ignored, but for mid-high range sounds, the sound radiated from the rear port 19 must change direction in order to reach the front. , since the mid-high range components are sufficiently attenuated, there is no problem with dual sound sources. Here, the front port 12 and the back port 1
An explanation will be added regarding the mutual interference in item 9. When the diaphragm of the speaker 16 moves backward, air flows in the direction of the flow path 24 and the flow path 25. In this configuration, since the inner opening 15 of the port 12 and the inner opening 26 of the rear port 19 are on different axes, mutual interference of air is extremely reduced. If both are arranged on the same axis, the direction of air flow in the inner side openings will be in the opposite direction, and a vortex will occur near the center of the inner side openings, which will generate a large amount of energy. There will be a loss. In other words, when air enters the port, a compressed vortex is generated near the center of the inner opening, and when air flows out, an expanded vortex is generated.
Although energy loss occurs, the amounts of loss are not the same, resulting in large phase distortion. That is, reducing mutual interference of air is an important element in suppressing phase distortion.

Further, since the port 12 is bent, no light is directly transmitted from the port 12 to the rear port 19.

As described above, according to this embodiment, by arranging the inner opening 15 of the port 12 and the inner opening 26 of the rear port 19 on different axes, mutual interference of air between the ports is significantly reduced. Therefore, the phase distortion can be made extremely small.

Next, the port shape of the present invention will be explained.

FIG. 4 is a sectional view of a port in one embodiment of the present invention. In FIG. 4, the area of the outer opening 13 is shown. is the maximum, and the inner cross-sectional area of the pipe decreases as it goes deeper into the port. Reference numeral 14 denotes a portion with a minimum cross-sectional area, and an inner opening portion 15 having an area larger than this area is provided on the lower surface of the port. The best area condition is that the area Ao of the outer opening 13 and the area Mu i of the inner opening 15 are the same, that is, person 1 = Ao. Also, it is better to round the rear corner portion 27 of the port.

FIG. 5 is a cross section of a port in another embodiment of the present invention,
It has a structure in which the back surface 28 of the port is inclined.

In the first embodiment, the port 12 is shown integrally formed with the baffle plate 11, but the port 12 may be provided in the cabinet 17.

Effects of the Invention As described above, the present invention arranges the openings at both ends of a port integrally formed with a baffle plate or cabinet on different axes, and furthermore, the area of the openings at both ends is made smaller than the minimum cross-sectional area inside the port. By increasing the angle, it is possible to realize a phase inversion type speaker device with extremely little phase distortion and excellent localization of sound images.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a port section of a speaker device according to an embodiment of the present invention, FIG. 2 is a perspective view of a speaker device according to a first embodiment of the present invention, and FIG. 3 is a perspective view of a port section of a speaker device according to an embodiment of the present invention. 4 is a sectional view of a port portion of a speaker device in an embodiment of the present invention; FIG. 6 is a sectional view of a port portion of a speaker device in another embodiment of the present invention; FIG. 6 is a perspective view of a conventional speaker device.
FIG. 7 is a cross-sectional view of the port portion of the same speaker device, and FIG. 8 is a cross-sectional view of the port portion of the same speaker device. 11...Baffle plate, 12...Hoard, 13...10. Outer opening, 14... Minimum cross-sectional area part, 15... Inner opening.

Claims (1)

[Claims] The baffle plate or cabinet and the port are molded into a body by resin molding, etc., the openings at both ends of the port are arranged on different axes, and the area of the openings is set to be larger than the minimum cross-sectional area within the port pipe. A phase-inverting speaker device with a large configuration.