JPH04271598A - Speaker system for low frequency sound reproduction - Google Patents

Abstract

PURPOSE:To widen the reproduction band and to realize low sound frequency reproduction by separating the inside of a speaker box into three chambers arranged side by side, providing a port to the same side of them respectively and providing two speakers to a central chamber so as to face other chambers. CONSTITUTION:The inside of a speaker box 1 is separated into three chambers 1A-1C side by side with two partition plates 2, 3. A port 8 (9, 10) is fitted to an opening 11 (12, 13) provided to a front plate 1a of each of the chambers 1A-1C respectively. Cones 6a, 7a of speaker units 6, 7 are arranged respectively to the openings 4, 5 provided to the partition plates 2, 3. Let the resonance frequency of the ports 8-10 be respectively fa-fc and the relation of them be fc<fa<fb, then the phase of a sound wave radiating from the port 8 is in phase with the sound wave radiating from a front side of a speaker when the reproduced frequency is higher than the resonance frequency and in opposite phase the sound wave radiating from the front side of a speaker when the reproduced frequency is lower than the resonance frequency. On the other hand, the phase of the sound wave radiating from the ports 9, 10 is opposite to the phase above.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speaker system for reproducing bass sounds.

0002

2. Description of the Related Art Ported speaker systems are available as bass reproduction speaker systems, and a typical example is a so-called bass reflex type speaker system.

[0003] This is an attempt to extend the bass sound by utilizing the sound from the rear side of the speaker unit, and as shown in FIG. It has a structure in which a port 24 is installed inside the speaker box 21 so as to do so.

With this structure, the bass reflex type speaker system causes the air in the port 24 to resonate with the air in the speaker box 21 at a specific frequency (anti-resonance frequency of the bass reflex) due to Helmholtz resonance, and the air in the port 24 resonates with the air in the speaker box 21. It emits sound waves (b) to the outside of the
At frequencies higher than the above anti-resonance frequency, the phase of the sound wave from the port 24 is reversed and becomes the same phase as the sound wave (a) on the front side of the speaker unit 23, improving the efficiency of that part, and the characteristics shown in FIG. As shown in the figure, the bass range is improved.

Furthermore, among conventional speaker systems, there is a system called a dual bass drive system that further improves the efficiency of bass reproduction. This has the configuration shown in FIG. 7, in which the inside of a speaker box 31 is divided into upper and lower parts by a partition plate 32 as shown in the figure, and a speaker unit 33 is attached to this partition plate, and the front side of this speaker unit 33 is By providing ports 34 and 35 in the two rear chambers, respectively, and adjusting the port resonance to match the required reproduction band, the resonant frequency characteristics shown in FIG. 8 are obtained.

Therefore, in this dual bus drive type speaker system, the portion of the port 34 on the front side of the speaker unit 33 that is below the anti-resonance frequency, and the portion of the port 35 on the rear side of the speaker unit 33 that is above the anti-resonance frequency. By having the same phase, 2
Sound waves (a') and (b') from the two ports 34 and 35 are added to obtain a large sound pressure.

[0007]

[Problem to be Solved by the Invention] By the way, in the dual bus drive type speaker system as described above,
If you widen the playback band (increase the interval between the two port resonance frequencies), a dent will occur in the playback sound pressure characteristics, making it impossible to widen the band. In order to use it as a main full-range speaker side,
It is necessary to have a configuration that can reproduce up to the low frequency range.

The present invention is intended to solve these problems, and aims to expand the reproduction band of a bass reproduction speaker and improve the sound pressure.

[0009]

[Means for Solving the Problems] The present invention has two partition plates arranged in a speaker box so that three
Each room is divided into two rooms, and each room has a first, second, and third port that opens on the same side of the speaker box and makes the port resonate.
In addition, each partition plate has an opening, and first and second speaker units are attached to these partition plates so that the cone faces the opening, and both speaker units have the same polarity. The present invention provides a speaker system for bass reproduction in which an input lead wire is connected to the speaker system.

Furthermore, in the present invention, both of the speaker units are provided so as to be located in the center of each of the rooms, and the resonant frequencies of the respective ports are made different,
One side of the sound pressure vs. frequency characteristic from each port divided into two by each resonance frequency overlaps with one side of the other adjacent port, and the phases of the sound waves radiated from each port in such an overlapping portion are mutually The present invention also provides a bass reproduction speaker system in which the resonance of each port is set to be in phase.

[0011]

Therefore, in the present invention, the overlapping portions of the radiated sound waves of each port are in phase with each other, and the sound pressure of that portion is improved, making it possible to realize bass reproduction with a wide reproduction band and high sound pressure.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a side cross-sectional view showing an embodiment of a bass reproduction speaker system according to the present invention. Second and third rooms 1A, 1
The first and second partition plates partition into B and 1C, and openings 4 and 5 are provided in the plate surfaces, respectively. 6 and 7 are first and second speaker units attached to the partition plates 2 and 3, respectively, so as to be located in the central room 1A, and the front surfaces of the cone portions 6a, 7a are the openings 4, 5. Through it, you can see rooms 1B and 1C.

Reference numerals 8 to 10 refer to first, second and third cylinders which are provided in each of the above-mentioned chambers 1A to 1C and are made of a cylindrical body with openings at both ends.
ports, one end of which is attached to the front plate 1a of the speaker box 1, and an opening 1 provided in the front plate 1a.
The inside of each room 1A, 1B, and 1C is connected to the outside of the speaker box 1 through 1 to 13. As is clear from the figure, the above-mentioned speaker units 6 and 7 are oriented in opposite directions so as to apply the maximum pressure fluctuation to the air in the room 1A, and each speaker unit has an input signal corresponding to this. Lead wires (not shown) are connected so that signals of the same polarity are applied.

The speaker system of the present invention is constructed as described above, and in such a ported speaker system, the cross-sectional area and length of the port and the volume of the room continuous with the port are controlled by the Helmholtz resonance effect. No. 3
The resonant frequency can be freely designed using two parameters.

Therefore, each port 8 to 1 in the present invention
Let the resonance frequencies of 0 be fa, fb, and fc, respectively, and set the relationship between these frequencies to be fc<fa<fb.
As shown in the sound pressure vs. frequency and phase characteristics in Figure 2, when the reproduction frequency is higher than the resonance frequency, the phase of the sound wave emitted from the port 8 located on the rear side of the speaker is If this is the positive phase, it will be in the same phase (positive phase), and if it is low, it will be in the opposite phase (reverse phase).

[0016] Also, the port 9 located on the front side of the speaker
, 10, when the reproduction frequency is higher than the resonance frequency, the phase is negative, and when it is lower, the phase is positive. If we look at the overall characteristics of each port 8 to 10 in terms of sound pressure vs. frequency and phase characteristics, we get the characteristics shown in FIG. 4. As is clear from the figure, since the relationship between the frequencies of each port is fc<fa<fb as described above, the phases of the overlapping parts are the same, and the sound pressure of that part is improved, and the characteristics as shown in the shaded area is lifted up. In other words, sound waves are emitted from each port 8, 9, and 10 according to the resonance characteristics, and within the effective playback band, the sound waves emitted from one port become weaker as the playback frequency changes. Since the radiated sound waves from the other port are also strengthened, the radiated sound waves from the port as a whole work to prevent the weakening of the radiated sound waves. Since three ports are provided, this operation is repeated twice to widen the playback band.

[0017]

[Effects of the Invention] Since the present invention is configured as described above, it is possible to realize bass reproduction with a wider reproduction band and higher sound pressure than the conventional dual bass drive system, and moreover, it is possible to realize bass reproduction with a wider reproduction band and higher sound pressure. If it is used for bass sounds, it will be possible to increase the low-range reproducible frequencies of the main full-range speaker unit compared to conventional ones. This makes it possible to provide a relatively small and inexpensive total speaker system including such a main speaker unit, and it is possible to widen the range of playback characteristics that can be set than in the past.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of a bass reproduction speaker system according to the present invention.

FIG. 2 is a sound pressure vs. frequency and phase characteristic diagram of the first port of the speaker system of this embodiment.

[Figure 3] The second speaker system in the speaker system of this embodiment
and a sound pressure versus frequency and phase characteristic diagram of the third port.

FIG. 4 is a comprehensive sound pressure versus frequency and phase characteristic diagram of each port in the speaker system of this embodiment.

FIG. 5 is a cross-sectional view of a conventional bass reflex speaker system.

FIG. 6 is a sound pressure versus frequency characteristic diagram of a conventional bass reflex speaker system.

FIG. 7 is a sectional view of another conventional dual bus drive system.

FIG. 8 is a sound pressure versus frequency characteristic diagram of another conventional dual bass drive system.

[Explanation of symbols]

1 Speaker box 1A 1st room 1B Second room 1C 3rd room 2 First partition plate 3 Second partition plate 4 Opening 5 Opening 6 First speaker unit 7 Second speaker unit 8 First port 9 Second port 10 Third port

Claims (3)

[Claims] Claim 1: The interior of the speaker box is partitioned into three adjacent rooms, a first, second, and third, by two partition plates, and each of the rooms has a port opening on the same side of the speaker box. First, second and third ports are provided to resonate, and each of the partition plates is provided with an opening,
A bass reproduction device characterized in that first and second speaker units are attached to these partition plates so that the front surface of the cone portion faces the opening thereof, and input lead wires are connected to both speaker units with the same polarity. speaker system. 2. The bass reproduction device according to claim 1, wherein the first and second speaker units are located in a first room located in the center of each of the rooms. speaker system. 3. The resonant frequency of each port is different, and one side of the sound pressure vs. frequency characteristic from each port divided into two by each resonant frequency overlaps with one side of the other adjacent port, 2. The bass reproduction speaker system according to claim 1, wherein the resonance of each port is set so that the phases of the sound waves radiated from each port in the overlapping portion are in phase with each other.