JP4085453B2 - Low-frequency electroacoustic transducer with amplification circuit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electroacoustic transducer with an amplifier circuit, uses an electroacoustic transducer having a plurality of drive units, applies signals of different bands to each drive unit, and adjusts the relative level of each signal. Thus, the present invention relates to a low-frequency dedicated electroacoustic transducer with an amplifier circuit, which can obtain a reproduced sound having a frequency characteristic in which only a desired band is amplified.
[0002]
[Prior art]
In general, in a reproduction device such as a stereo, a band pass filter (BPF), an equalizer circuit, etc. are usually used to enhance a specific band. For this purpose, an operation amplifier, a capacitor, a resistor, etc. are used. It was necessary to use a dedicated circuit. On the other hand, although a reproducing apparatus using a composite driving type electroacoustic transducer having a plurality of driving units has already been used, for example, in reproducing a low frequency signal in stereo, It only regenerates the same signal.
[0003]
[Problems to be solved by the invention]
In the conventional reproducing apparatus described above, a band-pass filter is used to obtain a desired tone by changing the frequency characteristics of the reproducing band, even in the system using the latter composite drive type electroacoustic transducer. A dedicated circuit such as (BPF) or an equalizer circuit has to be used, and there is a problem to be solved that an expensive device is required.
[0004]
Therefore, the present invention uses an electroacoustic transducer having two drive units in order to solve the above-described conventional problems, and among the amplifiers connected to each drive unit, a small number of components are provided in one amplifier. It is an object of the present invention to provide a low-frequency electroacoustic transducer with an amplifier circuit that can obtain a desired band enhancement effect simply by adding the.
[0005]
[Means for Solving the Problems]
The low-frequency dedicated electroacoustic transducer with an amplifier circuit according to the present invention for achieving the object will be described with reference to the reference numerals used in the description of the embodiments. The output side terminal and ground side terminal of the first amplifier 21 are provided in one voice coil 111 of the composite drive type electroacoustic transducer 1, and the second amplifier capable of adjusting the gain is provided in the other voice coil 112. output terminal and the ground-side terminal 22, are connected to each ground terminal in the common earth, to the one-way voice coil 111, the low frequency signal passed through the first low-pass filter LPF1 S1 There is supplied from the first amplifier 21, and the other one of the voice coil 112, the low-frequency signal S1 a further high-pass filter HPF and the second low-pass filter LPF2 and the band signal S2 having passed through the It is configured to be supplied from the second amplifier 22.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 showing the configuration of the first embodiment and the structure of the electroacoustic transducer 1 used in the first embodiment when implementing the low-frequency dedicated electroacoustic transducer with an amplifier circuit having such a configuration. Referring to FIG. 2, the electroacoustic transducer 1 according to the present embodiment is similar to the dynamic speaker having a known structure in FIG. 2, and the driving coil 11 and the first voice coil 111 are the same as those in FIG. The first coil 111 and the second coil 112 have a vibration system in which the two voice coils 112 are wound around a common winding frame 12 and the drive coil 11 is fixed to the center of the diaphragm 13. The structure is supported by the edge 16 inside the frame 15 so as to vibrate without contacting the inside of the magnetic gap of the magnetic circuit 14.
[0007]
In addition to the structure of FIG. 2 described above, the electroacoustic transducer 1 has a structure (Modification 1) in which two voice coils having a conventional structure are fixed to a common (for example, oval) diaphragm, or a conventional one. A structure in which two dynamic speakers having a structure are mounted in a common cabinet (Modification 2), or a structure in which two so-called ordinary speaker systems in which a dynamic speaker having a conventional structure is mounted in a cabinet are installed close to each other (Modification) 3) However, since it has the same function when implementing the present invention, it goes without saying that both belong to the scope of rights of the present invention.
[0008]
In the circuit portion of the first embodiment, the first low-pass filter (LPF1) uses a low-pass filter having a well-known structure that has been conventionally used for an amplifier of a low-frequency sound reproduction speaker device. . The first amplifier 21 is also a normal power amplifier that has been conventionally used.
[0009]
The second amplifier 22 has a capacitor C3 and a resistor R3, and a capacitor C1 and a resistor R1 connected to the input circuit, and a capacitor C2, a resistor R4, and a variable resistor R2 connected to the feedback circuit. The resistor R3 forms a high-pass filter (HPF), and the capacitor C1 and the resistor R1 form a second low-pass filter (LPF2). The gain of the second amplifier 22 is adjusted by changing the variable resistor R2. Capacitors, resistors, variable resistors, etc. connected to the second amplifier 22 may be parts conventionally used. Also, the main body of the second amplifier 22 uses a conventional power amplifier that has been conventionally used, like the first amplifier 21.
[0010]
The operation of the first embodiment will be described. First, FIG. 6 shows the frequency characteristics of the first low-pass filter LPF1. The input signal Si passes through the first low-pass filter LPF1, the high-frequency signal is cut off, and the low-frequency signal S1 is input to the first amplifier 21. An output side terminal and a ground side terminal of the first amplifier 21 are connected to one voice coil 111 of the electroacoustic transducer 1. The output of the first amplifier 21 is supplied to one voice coil 111 of the electroacoustic transducer 1, and the driving force generated in one voice coil 111 of the electroacoustic transducer 1 has substantially the same frequency characteristics as in FIG. Show.
[0011]
The other voice coil 112 of the electroacoustic transducer 1 is connected to the output-side terminal and the ground-side terminal of the second amplifier 22 whose gain can be adjusted. The ground terminals of the first amplifier 21 and the second amplifier 22 are connected to a common ground. The second amplifier 22 is connected to a high-pass filter HPF having a frequency characteristic shown in FIG. 7 and a second low-pass filter LPF 2 having a frequency characteristic shown in FIG. 8, to which the first low-pass filter is connected. Since the low-frequency signal S1 passing through the LPF 1 is applied, the overall frequency characteristic is the bandpass characteristic shown in FIG. Furthermore, since the gain of the second amplifier 22 is variable, the output thereof is a band signal S2 whose output level changes within a range of about 20 DB as shown in FIG. 10, and the other voice of the electroacoustic transducer 1 is obtained. Supplied to the coil 112, the voice coil 112 generates a driving force having substantially the same frequency characteristics as in FIG.

[0012]
Therefore, the total driving force acting on the vibration system of the electroacoustic transducer 1 is the sum of the driving forces generated in the voice coils 111 and 112, and has the frequency characteristics shown in FIG. As is apparent from this frequency characteristic, several circuit elements such as a resistor and a capacitor are simply added to one amplifier of a conventional bass reproduction speaker device with a composite drive type amplifier. With a simple and inexpensive configuration that only increases or decreases the gain, without using an expensive equalizer circuit or a bandpass filter, in addition to the characteristic as a basic bass reproduction amplifier (characteristic of FIG. 6), in this embodiment, 50 Hz. It can be seen that the band centered on is enhanced. If the gain of the second amplifier 22 is lowered, the overall frequency characteristic is greatly affected by the frequency characteristic of the first amplifier 21, and finally the characteristic as a conventional bass reproduction amplifier (characteristic of FIG. 6). It becomes. By changing the cutoff frequencies of the first and second low-pass filters LPF1 and LPF2 and the high-pass filter HPF, the band to be enhanced can be changed according to preference. In addition, the output sound pressure characteristic of a present Example becomes what added the electro-acoustic conversion characteristic of the electroacoustic transducer 1 to the frequency characteristic shown in FIG. 11 (illustration omitted).
[0013]
【Example】
Although the structure of the first embodiment has been described above, the constants of the filters and the like for obtaining the characteristics of FIGS. 6 to 11 are such that the number of cutoffs of the first low-pass filter LPF1 is about 70 Hz and the second low The cutoff frequency of the high-pass filter LPF2 is about 730 Hz, and the cutoff frequency of the high-pass filter HPF is 1.6 kHz. Further, the resistor R4 of the gain adjusting feedback circuit of the second amplifier 22 is 1 kΩ, the resistor R2 is 1 k to 1 MΩ, and the capacitor C2 is 0.001 μF. As described above, the desired frequency band enhancement effect of the overall frequency characteristics can be obtained by changing the number of cutoffs of the filters and the numerical values of the resistors R1, R4, and C2.
[0014]
In addition to the speaker having the structure shown in FIG. 2, it is possible to use a converter having another structure as the electroacoustic conversion device 1. In the first modification shown in FIG. 3, the drive coil 11 is used as the first voice coil 111. The second voice coil 112 is wound around different winding frames 12 and two conventional voice coils are fixed to a common (for example, oval) diaphragm 13.
[0015]
In the second modification shown in FIG. 4, speakers 101 and 102 each having a single voice coil in the electroacoustic transducer 1 are attached to a common cabinet 17. Therefore, the voice coil 111 is provided in the speaker 101, the voice coil 112 is provided in the speaker 102, the amplifier 21 is connected to the speaker 101, and the amplifier 22 is connected to the speaker 102, respectively. In this modification, since a dynamic speaker having a conventional structure can be used as it is, it is easy and inexpensive as an apparatus, and it is easy to increase the total effective area of the diaphragm, and is therefore suitable for exclusive use for bass reproduction. It has the characteristic which is a structure.
[0016]
5 is a so-called normal speaker system in which the above-described speakers 101 and 102 are individually housed in an independent cabinet 17, and two such normal speaker systems are installed close to each other. Needless to say, this structure has the same function and both belong to the scope of the right of the present invention.
[0017]
The embodiments and modifications considered to be representative of the present invention have been described above. However, the present invention is not necessarily limited to the structures of these embodiments and modifications, and the above-described configuration requirements according to the present invention are satisfied. It can be implemented with appropriate modifications within the scope of the present invention, achieving the object of the present invention and having the following effects.
[0018]
【The invention's effect】
The low-frequency dedicated electroacoustic transducer with an amplifier circuit according to the present invention uses a composite drive type electroacoustic transducer having two drive units, and among the amplifiers connected to each drive unit, a small number is included in one amplifier. Since the reproduction band and the reproduction level are made different with respect to the other amplifier to obtain the desired band enhancement effect, unlike the conventional low-frequency dedicated speaker with an amplifier, The timbre of the reproduced sound can be adjusted according to the preference, and in the audio field, it has the effect of significantly increasing the enjoyment when listening to the reproduced sound.
[0019]
In addition, in order to obtain the above effect, it is not necessary to use a costly dedicated circuit such as a band filter or a graphic equalizer as in the conventional reproducing apparatus having the same function. is there. Therefore, by implementing the present invention, it is possible to easily obtain a desired band enhancement effect and efficiently improve the sound quality, and to provide an inexpensive low-range dedicated electroacoustic transducer with an amplifier circuit. It came to be done.
[Brief description of the drawings]
FIG. 1 is a circuit block connection diagram showing a configuration of a first embodiment.
FIG. 2 is a cross-sectional view of the electroacoustic transducer of the first embodiment.
FIG. 3 is an explanatory diagram of a first modification of the electroacoustic transducer.
FIG. 4 is an explanatory diagram of a second modification of the electroacoustic transducer.
FIG. 5 is an explanatory diagram of a third modification of the electroacoustic transducer.
FIG. 6 is a frequency characteristic diagram of the first low-pass filter according to the first embodiment.
FIG. 7 is a frequency characteristic diagram of the high-pass filter.
FIG. 8 is a frequency characteristic diagram of the second low-pass filter.
FIG. 9 is an overall frequency characteristic diagram through the first and second low-pass filters and the high-pass filter.
FIG. 10 is an output level variable range of the second amplifier and its frequency characteristic diagram.
FIG. 11 is a diagram showing a level variable range of sound output of the electroacoustic transducer and a frequency characteristic diagram thereof.
[Explanation of symbols]
1 electroacoustic transducer 101 electrodynamic speaker 102 electrodynamic speaker 11 drive coil 111 voice coil 112 voice coil 12 winding frame 13 diaphragm 14 magnetic circuit 15 frame 16 edge 17 cabinet 21 first amplifier 22 second amplifier LPF1 First low pass filter LPF2 second low pass filter HPF high pass filter

Claims (3)

One voice coil (111) of the composite drive type electroacoustic transducer (1) having two voice coils (111) and (112) is connected to the output side terminal of the first amplifier (21) and the ground. The side terminal is connected to the other voice coil (112), and the output side terminal and the ground side terminal of the second amplifier (22) whose gain can be adjusted are connected to each other with the ground terminal as a common ground . wherein the 1-way voice coil (111) is a low frequency signal that has passed through the first low-pass filter a (LPF1) (S1) is supplied from the first amplifier (21), and the other voice coil ( the 112), the low-frequency signal (S1) to further high-pass filter (HPF) and a second low-pass filter (LPF2) band signal passed through the (S2) a second amplifier (22) A low-frequency electroacoustic transducer with an amplifier circuit, characterized by being supplied from:  The electroacoustic transducer (1) is a single electrodynamic loudspeaker having a composite voice coil having a common diaphragm (13) for the two voice coils (111) and (112). The low-range dedicated electroacoustic transducer with an amplifier circuit according to claim 1.  The low-frequency dedicated electroacoustic transducer with an amplifier circuit according to claim 1, wherein the electroacoustic transducer (1) is an assembly in which two electrodynamic speakers (101) and (102) are arranged close to each other. apparatus.

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