JPH0638290A - Speaker equipment - Google Patents

Abstract

PURPOSE:To reproduce an ultralow frequency sound over a wide band by providing a peak to each sound radiating from each duct at a different frequency and synthesizing them. CONSTITUTION:The inside of a cabinet main body 1 is parted into two parts by a partition plate 2, and a speaker unit 3 is mounted on the partition plate 2. Furthermore, an enclosed sub cabinet 4 is formed to a rear side of the speaker unit 3 through the partitioning and a main cabinet 5 is formed to a front side of the speaker unit 3. The main cabinet is separated by a partition plate 8 so as to form two air chambers 5a, 5b having ducts 6, 7 respectively. Since the air chamber 5a(5b) has the duct 6(7) respectively, the chambers act like a Helmholtz resonator. The resonance frequency of the air chambers 5a, 5b is made different by differentiating the length or the cross sectional shape of the ducts 6, 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speaker device for reproducing super bass using a Helmholtz resonator.

[0002]

2. Description of the Related Art As a speaker device for reproducing super bass, ASW (Acoustic Sup) announced by Henry Lang of the US
er Woofer) is known. This ASW is designed for the purpose of reproducing sound outside the frequency band that can be reproduced by the speaker unit.

Basically, as shown in FIG. 4, the structure is such that a sub cabinet 12 is provided on the rear side of the speaker unit 11, while a main cabinet that functions as a Helmholtz resonator is provided on the front side of the speaker unit 11. 13 is provided, and a duct 14 is formed in this main cabinet 13. In such a speaker device, the main cabinet 13 plays a role as an acoustic band pass filter, and by lowering the resonance frequency of the main cabinet 13 below the reproduction band of the speaker unit 11, the speaker unit It becomes possible to reproduce super bass beyond the capabilities of 11.

FIG. 5 shows a mechanical equivalent circuit of the above speaker device.

In this equivalent circuit, the speaker unit 11
The equivalent resistance R ₀ , the effective mass M _{0 of the} vibration system, the equivalent stiffness S _{0 of} the speaker unit 11 and the acoustic load Sa of the speaker unit 11 are connected in series to the driving force F of the resonator, and the stiffness Sc of the resonator and the duct 14 are connected. A resonance circuit composed of the equivalent mass Md in is connected.

Based on the above equivalent circuit, the frequency characteristic of the sound radiated from the duct 14 is measured by the speaker unit 11
FIG. 6 shows an example theoretically calculated assuming that the frequency characteristic of is flat. In this figure, five types of curves are resonance frequencies (Resonance frequencies of Helmholtz), respectively.
In order to change, the length of the duct 14 is made different, and the result is obtained. As can be seen from the figure, if the length of the duct 14 is lengthened (30 cm), the resonance frequency can be lowered, and the reproduction of ultra-low frequencies becomes easy.

[0007]

However, the duct 14
If the length is increased as described above, the reproduction band is narrowed and only the sound of a specific frequency can be reproduced. In order to change the resonance frequency, a method of changing not only the length of the duct 14 but also the area of the duct 14 can be considered, but the result is similar to the above case. As described above, the conventional technique has a problem that even if an attempt is made to reproduce a wide band sound at a low frequency, there is no degree of freedom in design, and severe conditions are involved in the speaker cabinet and the speaker unit 11.

[0008]

In order to solve the above-mentioned problems, a speaker device of the present invention is provided with a speaker unit and also has a duct opening to the outside, and A plurality of air chambers forming a Helmholtz resonator for resonating sounds of a predetermined resonance frequency are provided, and each air chamber is set to a different resonance frequency by a duct.

[0009]

In the above structure, since the resonance frequencies of the air chambers are different, the sound radiated from each duct has a peak at each resonance frequency. Therefore, the sound heard by the listener as the reproduced sound has a wide band because it is a combination of the above sounds.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following will describe one embodiment of the present invention with reference to FIGS.

The speaker device according to this embodiment includes a box-shaped cabinet body 1 as shown in FIG. The interior of the cabinet body 1 is divided into two parts by a partition plate 2, and a speaker unit 3 is attached to the partition plate 2. A closed sub cabinet 4 is formed on the rear side of the speaker unit 3, and a main cabinet 5 is formed on the front side of the speaker unit 3. The main cabinet 5 is provided with two ducts 6 and 7.

The main cabinet 5 is partitioned by a partition plate 8 arranged on the extension line of the center of the speaker unit 3 so that two air chambers 5a and 5b each having ducts 6 and 7 are formed. The air chambers 5a and 5b function as Helmholtz resonators by having the ducts 6 and 7, respectively. Duct 6/7
It is formed such that the length or cross-sectional shape (circular, rectangular, etc.) the resonance frequency f _a · f _b different values by (f _a <f _b). Thereby, the air chambers 5a and 5b
Respectively resonate the sound radiated from the speaker unit 3 at the resonance frequencies f _a and f _b .

FIG. 2 shows a mechanical equivalent circuit of the present speaker device configured as described above.

In this equivalent circuit, the driving force F of the speaker unit 3 is connected in series with the equivalent resistance R ₀ , the vibration system effective mass M ₀ , the equivalent stiffness S _{0 of} the speaker unit 3, and the acoustic load Sa of the speaker unit 3. And 2 more
Resonant circuits Z ₁ and Z ₂ are connected in series. Resonance circuit Z ₁ has a Fuchifunesu Sc ₁ of the air chamber 5a duct 6
And the equivalent mass Md ₁ in is provided in parallel. In addition, the resonance circuit Z ₂ has a margin S of the air chamber 5b.
c ₂ and the equivalent mass Md ₂ in the duct 7 are provided in parallel.

Based on the above equivalent circuit, the ducts 6 and 7
The frequency characteristics of the sound emitted from the speaker unit 3
An example of theoretical calculation assuming that the frequency characteristic of is flat is shown in FIG. In this figure, ducts 6 and 7
The sound radiated from each has peaks at different frequencies as shown by the curves indicated by the one-dot chain line and the two-dot chain line, respectively. Therefore, the sound heard by the listener is a composite of the sounds radiated from the ducts 6 and 7, as shown by the solid line in the figure, and it is possible to reproduce the super bass in a wide band.

In this embodiment, the two air chambers 5a
Although the configuration including 5b has been described, it may include three or more air chambers.

[0017]

As described above, the speaker device of the present invention is provided with the speaker unit and has the duct that opens to the outside so as to generate the sound of the predetermined resonance frequency among the sounds radiated forward from the speaker unit. A plurality of air chambers forming a Helmholtz resonator for resonance are provided, and each air chamber is set to a different resonance frequency by a duct.

As a result, the sound radiated from each duct has peaks at different frequencies. Therefore, by combining these, it is possible to reproduce an ultra-low sound in a wide band.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing the configuration of a speaker device according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a mechanical equivalent circuit of the speaker device of FIG.

FIG. 3 is a graph showing frequency characteristics of reproduced sound obtained by the speaker device of FIG.

FIG. 4 is a vertical sectional view showing a configuration of a conventional speaker device.

5 is a circuit diagram showing a mechanical equivalent circuit of the speaker device of FIG.

FIG. 6 is a graph showing frequency characteristics of reproduced sound calculated by changing the length of the duct in the speaker device of FIG.

[Explanation of symbols]

 3 Speaker unit 5 Main cabinet 5a ・ 5b Air chamber 6.7 Duct 8 Partition plate

Claims (1)

[Claims] 1. A plurality of air chambers, each having a speaker unit and having a duct opening to the outside, forming a Helmholtz resonator for resonating a sound of a predetermined resonance frequency among sounds radiated forward from the speaker unit. A speaker device comprising: each air chamber having a different resonance frequency set by a duct.