JPH0662484A - Speaker system of bass reflex system - Google Patents

Abstract

PURPOSE:To provide the speaker system of the bass reflex system which reduces the occurrence of a peak and extends the reproducing band of the bass range essential to the bass reflex system. CONSTITUTION:A speaker unit 3 attached to a baffle plate 2 of a speaker cabinet 1 and two bass reflex ports 41 and 42 interposing the speaker unit 3 are provided. Aperture parts 41a and 42a in the speaker cabinet 1 of bass reflex ports 41 and 42 are provided at angles to axes of base reflex ports 41 and 42.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improving the characteristics of a bass reflex type speaker system.

[0002]

2. Description of the Related Art FIG. 6 is a cross-sectional side view of a conventional bass reflex type speaker system shown in, for example, "Speaker System (Lower)" (edited by Takeo Yamamoto, published by Radio Engineering Co., Ltd.). Is a speaker cabinet, 2 is a baffle plate that forms one surface of the speaker cabinet 1, 3 is a speaker unit attached to the baffle plate 2, 4 is a bass reflex port that is also attached to the baffle plate as the speaker unit 3, and 5 is a speaker cabinet The sound absorbing material is attached to the inner surface of 1.

The conventional bass reflex type speaker system is configured as described above, and in the low frequency range, driving the speaker unit 3 causes a compliance component due to the volume of the speaker cabinet 1 and a mass component of the bass reflex port 4 to cause Helmholtz resonance. (In a bass reflex type speaker system, this is called bass reflex resonance), acoustic emission is performed from the bass reflex port 4, and sound emission is performed from the speaker unit 3 in the mid-high range, whereby the bass reproduction band can be expanded.

FIG. 7 shows a conceptual diagram of output sound pressure-frequency characteristics of a bass reflex type speaker system. In FIG.
Characteristic A is the output sound pressure characteristic of the bass reflex port 4,
Resonance occurs at the bass reflex resonance frequency fb (Hz), and a single resonance characteristic that monotonically decreases above and below this frequency is obtained. Characteristic B is an output sound pressure frequency characteristic of the speaker unit 3, which is a bass reflex resonance frequency fb (Hz).
It has a characteristic with a dip. Characteristic C is characteristic A
Is a comprehensive characteristic of the bass reflex type speaker system by combining the characteristic B and the bass reflex resonance frequency fb (Hz).
In the above, the radiated sound from the characteristic A bass reflex port 4 and the characteristic B
The characteristic C is the sum of the characteristic A and the characteristic B because it is substantially in phase with the sound radiated from the speaker unit 3. However, at the bass reflex resonance frequency fb (Hz) or less, the radiated sound from the bass reflex port 4 of the characteristic A and the radiated sound from the speaker unit 3 of the characteristic B have almost opposite phases, so the characteristic C is the subtraction of the characteristic A and the characteristic B. It will be what you did. As a result, the overall characteristic C is a high-pass filter characteristic with a cutoff frequency of the bass reflex resonance frequency fb (Hz).

[0005]

Since the conventional bass reflex type speaker system is configured as described above,
There is a problem in that the tube resonance of the bass reflex port 4 causes peaks and dips on the overall characteristics.

FIG. 8 shows an example of a typical output sound pressure-frequency characteristic of a conventional bass reflex type speaker system. In the figure, a characteristic D is a sound emission characteristic from the bass reflex port 4, a characteristic E is a sound emission characteristic from the speaker unit 3, and a characteristic F is a comprehensive characteristic of the entire speaker system. In FIG.
At the frequency fr (Hz), the tube resonance of the bass reflex port 4 occurs, and the characteristic D has a large peak. Due to the resonance of the bass reflex port 4, a peak occurs in the overall characteristic of the characteristic F. In this example, the characteristic F has a peak in terms of the overall characteristic, but a dip may occur depending on the phase relationship of the sound radiation from the speaker unit 3.

The present invention has been made in order to solve the above-mentioned problems, and it is possible to reduce the occurrence of peaks due to the tube resonance of the bass reflex port and to expand the reproduction band of the bass reflex system originally in the bass reflex system. Aim to get a speaker system.

[0008]

A bass reflex type speaker system according to the present invention has two bass reflex ports, and an angle formed between an opening surface inside the speaker cabinet of the bass reflex port and a longitudinal axis of the bass reflex port. Is 6
It is set to 0 ° or less.

Further, the present invention has two bass reflex ports, and a sound absorbing material is arranged between the speaker unit and the opening of the bass reflex port in the speaker cabinet.

[0010]

In the bass reflex type speaker system according to the present invention, the angle between the opening surface inside the speaker cabinet of the bass reflex port and the axis in the longitudinal direction of the bass reflex port is set to 60 ° or less, so that in the bass range where bass reflex resonance occurs. Operates at that average length, and at the high frequency range where the tube resonance of the bass reflex port occurs, it becomes a form where many tubes from the shortest to the longest portion of the bass reflex port are gathered, and the tube resonance The frequencies are distributed over a wide range, and the emitted sound from the bass reflex port does not have a large peak.

Further, since the sound absorbing material is arranged between the speaker unit and the bass reflex port, there is no sound absorbing effect in the low frequency range and bass reflex resonance occurs, but in the high frequency range where the tube resonance occurs, the sound absorbing material is used. Because it absorbs sound
The sound waves that reach the opening in the speaker cabinet of the bass reflex port are weakened, and the level of tube resonance is reduced.

[0012]

EXAMPLES Example 1. Hereinafter, the present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing a bass reflex type speaker system according to a first embodiment of the present invention. In the figure, 41 is one bass reflex port attached to the baffle plate 2, 42 is another bass reflex port attached to the baffle plate 2, and 41a is a bass reflex port 41 that is cut diagonally toward the speaker unit 3. Bass reflex port opening inside speaker cabinet 1 of 4
Reference numeral 2a denotes a bass reflex port opening inside the speaker cabinet 1 of the bass reflex port 42 which is obliquely cut toward the speaker unit 3.

FIG. 2 is an output sound pressure-frequency characteristic diagram of the bass reflex type speaker system in the first embodiment of the present invention. In the figure, a characteristic G is a sound radiation characteristic from the bass reflex port 41 and the bass reflex port 42, a characteristic H is a sound radiation characteristic from the speaker unit 3, and a characteristic J is a comprehensive characteristic. The operation of this embodiment will be described below with reference to FIG.

In the bass range, the bass reflex port 4 is centered on the bass reflex frequency fb (Hz) which is a resonance frequency between the compliance component of the speaker cabinet 1 and the mass components of the bass reflex port 41 and the bass reflex port 42.
1 and the sound emission characteristic G from the bass reflex port 42 has a wide peak, and conversely, the sound emission characteristic from the speaker unit 3 has a bass reflex resonance frequency fb (Hz) dip. The overall characteristic J is a subtraction between the bass reflex port 41 and the sound emission characteristic G of the bass reflex port 41 and the sound emission characteristic H from the speaker unit 3 at the bass reflex resonance frequency fb (Hz) or lower, and at the bass reflex resonance frequency fb (Hz) or higher. The sound emission characteristic G of the bass reflex port 41 and the bass reflex port 42 is added to the sound emission characteristic H of the speaker unit 3. As a result, the overall characteristic J in the low tone range becomes a high-pass filter characteristic of the cutoff frequency fb (Hz). The operation in the bass range is the same as that of the conventional technique, and the bass reflex operation is normally performed.

In the mid-high range, the bass reflex port 42
The tube resonance occurs in a wide range from the tube resonance frequency generated at the longest length Lb of the above to the tube resonance frequency generated at the shortest length La of the bass reflex port 42. However, since the frequency of the tube resonance of the bass reflex port is dispersed, the level of the tube resonance of the bass reflex port is low, and it is possible to suppress the influence on the characteristics. 2 is a frequency of the tube resonance generated when the length of the bass reflex port is (La + Lb) / 2, and is a frequency range in which the tube resonance is generated in comparison with the characteristic of the conventional bass reflex speaker system of FIG. However, the level of tube resonance is very low and there is almost no disturbance on the overall characteristic J.

Example 2. FIG. 3 is a sectional side view showing a bass reflex type speaker system according to a second embodiment of the present invention. In the figure, 43 is one bass reflex port attached to the baffle plate 2, 44 is another bass reflex port attached to the baffle plate 2, and 43a is a bass reflex port diagonally cut in a direction opposite to the speaker unit 3. Reference numeral 43 denotes a bass reflex port opening portion inside the speaker cabinet 1, and reference numeral 44a denotes a bass reflex port opening portion inside the speaker cabinet 1 of the bass reflex port 44 which is obliquely cut in a direction opposite to the speaker unit 3.

Next, the operation will be described. It should be noted that since the basic operation in the bass range and the treble range is the same as that of the first embodiment, refer to the first embodiment. At a frequency that causes tube resonance of the bass reflex port 43 and the bass reflex port 44 in the high frequency range, the sound wave has a strong straight traveling property. Therefore, the bass reflex port opening 43a and the bass reflex port opening 44a are arranged in the speaker unit 3 as in the present embodiment.
If it is oriented in the opposite direction, the exciting force on the bass reflex port 43 and the bass reflex port 44 becomes small. Therefore, the tube resonance can be further reduced by the synergistic effect with the tube resonance reducing effect of the bass reflex port of the first embodiment.

Example 3. FIG. 4 is a sectional side view showing a bass reflex type speaker system according to a third embodiment of the present invention. In the figure, 45 is one bass reflex port attached to the baffle plate 2, 46 is another bass reflex port attached to the baffle plate 2, and 45a is a bass reflex port 45 that is cut diagonally in the direction of the speaker unit 3. The bass reflex port opening inside the speaker cabinet 1 is denoted by 46 a, and the bass reflex port opening 46 a inside the speaker cabinet 1 of the bass reflex port 46 is cut diagonally in the opposite direction of the speaker unit 3.

Next, the operation will be described. The operation in the bass range and the treble range is the same as that of the first embodiment, so refer to the first embodiment. In the high frequency range, the bass reflex port opening 45a is provided inside the speaker cabinet 1.
When a standing wave is generated in the direction between the bass reflex port opening 46a and the bass reflex port opening 46a (vertical direction in FIG. 4), the bass reflex port opening 4
5a is in the direction opposite to the wall surface of the speaker cabinet 1, and the bass reflex port opening 46a is in the speaker cabinet 1.
Since they face the wall surface of each, the exciting force to each bass reflex port has a phase difference. Therefore, the influence of the internal standing wave can be reduced as compared with the first and second embodiments.

Example 4. FIG. 5 is a sectional side view showing a bass reflex type speaker system according to a fourth embodiment of the present invention. In the figure, reference numeral 51 denotes a breathable sound absorbing material arranged between the speaker unit 3 and the bass reflex port 4.

In the low sound range, the sound absorbing material 51 has almost no sound absorbing effect or sound insulating effect. Therefore, like the conventional bass reflex type speaker system, the bass reflex due to the resonance of the compliance component of the speaker cabinet 1 and the mass component of the bass reflex port 4 is generated. Resonance occurs. In the high sound range, the sound absorbing material 51 has a sound absorbing effect, and the vibrating force to the bass reflex port 4 is reduced as compared with the case where the sound absorbing material 51 is not provided. For this reason, it is possible to effectively reduce the tube resonance of the bass reflex port 4 generated in the high frequency range and the entire unnecessary radiation such as the standing wave inside the speaker cabinet 1.

[0022]

As described above, according to the present invention, the opening in the speaker cabinet of the bass reflex port is arranged obliquely with respect to the axis of the bass reflex port.
The tube resonance of the bass reflex port can be reduced at low cost.

Further, according to the present invention, since the sound absorbing material is disposed between the speaker unit and the opening of the bass reflex port, it is unnecessary due to a resonance phenomenon such as a standing wave inside the speaker cabinet including the tube resonance of the bass reflex port at a low cost. The total radiation can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional side view showing a bass reflex type speaker system in a first embodiment of the present invention.

FIG. 2 is an output sound pressure-frequency characteristic diagram of the bass reflex type speaker system in the first example of the present invention.

FIG. 3 is a sectional side view showing a bass reflex type speaker system in a second embodiment of the present invention.

FIG. 4 is a sectional side view showing a bass reflex type speaker system according to a third embodiment of the present invention.

FIG. 5 is a sectional side view showing a bass reflex type speaker system according to a fourth embodiment of the present invention.

FIG. 6 is a sectional side view showing a conventional bass reflex type speaker system.

FIG. 7: Output sound pressure of bass reflex type speaker system −
It is a conceptual diagram of a frequency characteristic.

FIG. 8 is an output sound pressure-frequency characteristic diagram of a conventional bass reflex type speaker system.

[Explanation of symbols]

 1 Speaker cabinet 2 Baffle board 3 Speaker unit 41,42 Bass reflex port 41a, 42a Bass reflex port opening

Claims (2)

[Claims] 1. In a speaker system in which a speaker unit is attached to a baffle plate in a speaker cabinet and two bass reflex ports are provided on the baffle plate, an opening surface of the bass reflex port in the speaker cabinet and a length of the bass reflex port. A bass reflex type speaker system characterized in that an angle formed with a direction axis is 60 ° or less. 2. A speaker system in which a speaker unit is attached to a baffle plate in a speaker cabinet and two bass reflex ports are provided on the baffle plate, between the speaker unit and the opening in the speaker cabinet of the bass reflex port. Bass reflex speaker system characterized by arranging sound absorbing material.