JPH02202296A - Speaker system - Google Patents

Abstract

PURPOSE:To acquire the flat sound pressure characteristics in comparison with a conventional speaker system by driving a horn having its single side closed via two speaker units having different driving positions and therefore securing the effect equivalent to that ensured by synthesizing the reproduced sounds obtained by two horns of different lengths. CONSTITUTION:The single side of a horn 6 is closed and a 1st speaker unit 7 is set near this closed part. Then a 2nd speaker unit 8 is added with a space secured to the unit 7. In addition, the l1/l2 ratio is set at 1.1-2 where l1 shows the effective length between the unit 7 and a horn opening 9 and l2 shows the effective length between the unit 8 and the opening 9 respectively. Then the l1/l2 ratio so that the length l2 of the horn is equal to an even multiple of 1/2 wavelength with drive of the unit 8 at a frequency with which the length l1 of the horn is equal to an odd multiple of 1/2 wavelength with drive of the unit 7. As a result, the flat sound pressure characteristics can be obtained owing to the offset function secured between the top and the bottom of the sound pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a speaker system having a horn on the back of a speaker unit.

BACKGROUND OF THE INVENTION One of the conventional speaker systems for expanding the bass range is a pack-loaded horn type speaker system.

Hereinafter, the conventional pack load horn type speaker system mentioned above will be explained with reference to the drawings.

FIG. 3 shows a structural sectional view of the above speaker system.

In FIG. 3, 1 is a speaker unit, 2 is a cabinet in which the speaker unit 1 is mounted, 3 is a horn in which a throat 4 is connected to the cabinet 2, and 5 is an opening of the horn 3.

The operation of the pack load horn type speaker system configured as described above will be explained below.

Sound emitted from the rear side of the speaker unit 1 is guided from the horn 4 to the horn 3 and radiated through the opening 6 thereof. As is well known, in order to effectively produce the horn effect, it is necessary to increase the expansion ratio of the horn, but this increases the volume of the horn, so in small speaker systems, a horn that is similar to a straight tube is used. Such a horn produces a resonance phenomenon at a specific frequency determined by its total length. If the total length of the horn is L and the speed of sound in the air is C, then the resonance frequency fn = C/
4Lx (2n+1), where n = 0, 1 + 2+
・・・・・・N, when n=o, a resonance phenomenon occurs where 1/4 wavelength is equal to the horn length, and acoustically enhanced sound is radiated from the horn opening 6, reaching the bass reproduction limit. This will greatly improve efficiency in the vicinity. Also, at a frequency where 1/2 wavelength is equal to the horn length, the speaker unit 1
The sound emitted from the front of the speaker unit 1 and the sound emitted from the rear of the speaker unit 1 from the horn aperture 6, which are originally in reverse phase, are in phase due to a phase delay of half a wavelength compared to the sound from the front. The sound pressure level increases as the sound pressure level increases. Furthermore, when n = 2, a resonance phenomenon occurs in the sea horn whose 3/4 wavelength is equal to the horn length, and as in the case where n = o,
Acoustically enhanced sound is radiated through the horn aperture 6. Therefore, it was possible to realize a speaker system with high efficiency in the bass range.

Problems to be Solved by the Invention However, with the above configuration, as shown in the sound pressure frequency characteristics of FIG. The radiated sound and the sound radiated from the rear surface of the speaker unit from the horn opening 6 have opposite phases and cancel each other out, producing a large valley in sound pressure.

As the frequency increases, the horn repeats the above operation, and the synthesis of the sound in front of the speaker unit 1 and the sound radiated from the horn 3 periodically produces large peaks and troughs of sound pressure, degrading the sound quality of the speaker system. This was a contributing factor.

In view of the above-mentioned problems, the present invention provides a speaker system that improves the radiation efficiency in the bass range, has less disturbance in sound pressure characteristics, and has excellent sound quality.

Means for Solving the Problems To achieve this object, the speaker system of the present invention has one side of the horn closed, a first speaker unit arranged near this closure, and a first speaker unit υ
A second speaker unit is arranged at intervals, and further,
When the effective length from the first speaker unit to the horn opening is tl, and the effective length from the second speaker unit to the horn opening is 12, the configuration is such that the l1/l2 ratio is 1.1 to 2. There is.

Function According to the above configuration, the horn driven by the first speaker unit operates as a horn with an effective length t1,
At frequencies where tl is approximately an odd multiple of 1/2 wavelength, the sound from the front of the speaker unit 1 and the sound radiated from the horn opening are in phase and added, and at frequencies where tl is approximately an even multiple, they are out of phase. canceled out. - The horn driven by the loudspeaker unit of the power tube 2 also acts as a horn to the effective length. When the first speaker unit is driven, the effective length 12 of the horn becomes an even number of 1/2 wavelengths. If the ratio of 11/12 is set so as to be equal to the ratio of 11/12, a flat sound pressure characteristic can be realized by the canceling effect of the peaks and troughs of the sound pressure.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a structural sectional view of a speaker system according to an embodiment of the present invention. In FIG. 1, reference numeral 6 indicates a horn with one side closed, reference indicates a first speaker unit placed near the closed portion of the horn 6, and reference numeral 8 indicates a second speaker unit placed at a distance from the first speaker unit 7. The unit 9 has a horn 6 o opening, the effective length from the first speaker unit 7 to the opening 9 is tl, and the effective length from the second speaker unit 8 to the opening 9 is 4. Reference numeral 1o designates a mid-to-high frequency speaker unit that is placed between the first speaker unit 7 and the second speaker unit 8 and whose back surface is sealed.

The operation of the speaker system configured as above will be explained below. First, the first speaker unit 7
When the horn 6 is driven by , the effective length from the first speaker unit 7 to the aperture 9 of the horn 6 is tl. The sound from the front and the sound from the back of the speaker unit 7 emitted from the horn opening are in phase and added together. Furthermore, at frequencies where the effective length t1 is approximately an even number multiple of 1/2 wavelength, the sound from the back of the speaker unit 7,
The sound emitted from the horn opening has an opposite phase and is canceled out. Next, when the horn 6 is driven by the second speaker unit 8, since the effective length from the second speaker unit 8 to the horn opening is the same, the horn operates in the same manner as when the first speaker unit 7 is driven. Therefore, if we match the frequency where tl is an even part of 1/2 wavelength with the frequency where t2 is an odd multiple of 1/2 wavelength, □ = 1.3 = 1.2, and the peaks and troughs of sound pressure are The ratio of t and /12 changes depending on the frequency to be matched.

However, the peaks and troughs of sound pressure are not so steep and have a certain amount of bandwidth, so the l1/l2 ratio is 1.1 to 2.
If so, it is possible to make the peaks and troughs of the sound pressure almost the same.

In the example of FIG. 1, if t1/Z2=1-2, the second
As shown in the figure, the peaks and troughs of the sound pressure generated by the horn 6 can be canceled out by driving the speaker unit, door, and 8, and the sound pressure characteristics of the speaker system in the low frequency range can be made flat. can.

Furthermore, in this embodiment, a speaker unit 1o for medium and high frequencies whose back surface is sealed is arranged between the first speaker unit 7 and the second speaker unit 8, so that the operation of the horn 6 is not affected. The system reproduces the mid-to-high range from the front of the unit without giving any additional energy to the unit, thereby making it possible to reproduce the entire range.

Effects of the Invention As described above, the present invention moves a horn with one side closed by two speaker units with different drive positions, and achieves an effect equivalent to combining the sound reproduced by two horns with different lengths. By obtaining the above, it is possible to realize a speaker system having flat sound pressure characteristics compared to conventional speaker systems.

[Brief Description of the Drawings] Fig. 1 is a sectional view showing the structure of an embodiment of the speaker system of the present invention, Fig. 2 is a sound pressure frequency characteristic diagram of the same speaker system, and Fig. 3 is a diagram of the conventional speaker system. A sectional view showing the structure, and FIG. 4 is a sound pressure frequency characteristic diagram of the same speaker system. 6. Mountain... Horn, 7. 8... Speaker unit, 9... Horn opening. Name of agent: Patent attorney Shigetaka Awano and 1 other person Law-fuichiso 8-Ichimata toichikauni-no ¥9--ichifuichisoopening□ya1zl-kayuniyk1suiseijingkin1- −−su(′
-Kayuni 93--Ikei-n

Claims (3)

[Claims] (1) A speaker system characterized in that a plurality of speaker units are arranged at intervals on a horn whose one side is closed. (2) The first speaker unit is placed near the closed part of the horn, the second speaker unit is provided on the opening side from the first speaker unit position, and the effective length from the first speaker to the horn opening is l_1 ．． When the effective length from the second speaker unit to the horn opening is l_2, l_1/
2. The speaker system according to claim 1, wherein the ratio of l_2 is 1.1 to 2. (3) The speaker system according to claim 2, characterized in that a mid-high frequency speaker unit whose back surface is sealed is disposed between the first and second speaker units.