JPH067676Y2 - Loudspeaker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the invention: [Industrial field of application] The present invention relates to a loudspeaker, and is particularly used in the field of expanding and enhancing a low frequency range.

[Prior Art] FIG. 3 shows a Japanese Patent Application No. 60-6997 filed by the same applicant.
It is a block circuit diagram of the loudspeaker of No. 3 (application date: May 10, 1985).

[Problems to be Solved by the Invention] In the loudspeaker shown in FIG. 3, the output between the hot side terminal 1h of the output of the power amplifier 1 and the hot side terminal 2h of the output of the power amplifier 2 has a low frequency band enhanced. However, since the high frequency band is not cut, there is a drawback in that the bass reproduced from the bass speaker 4 slightly contains a high-frequency component sound, which makes it difficult to obtain high-quality sound.

The present invention has been made in view of the above points, and is intended to provide a loudspeaker capable of expanding and enhancing the low frequency range at low cost and having excellent sound quality.

Configuration of the Invention: As shown in the block diagram of FIG. 1, the present invention is a low frequency band amplifier for amplifying a low frequency component of an L channel or R channel input signal (hereinafter referred to as an audio input signal) of a monaural signal or a stereo signal. 10 and an adder 25 that obtains an inverted output by adding a signal obtained by multiplying the audio input signal by α (where 0 <α <1) and a signal obtained by multiplying the output of the low frequency band amplifier 10 by (1-α) A first power amplifier 21 for amplifying the output of the adder 25, a low-pass filter circuit 24 for blocking high-frequency components of the output of the low-frequency band amplifier 10, and the low-pass filter circuit 24.
Of a signal obtained by doubling the output of the adder 25, a second power amplifier 22 for power-amplifying the output of the subtractor 25, and a second power amplifier 21 connected to the output of the first power amplifier 21. One output terminal 21h, a second output terminal 22h connected to the output of the second power amplifier 22, a bass speaker 32, and a mid-high range speaker 31. One input end of the mid-high range speaker 31. Of the bass speaker 32 has one input end connected to the first output terminal 21h and the other input end connected to the second output terminal 2b.
It is a loudspeaker connected to each 2h.

[Embodiment] FIG. 2 is a circuit block diagram for explaining an embodiment of the present invention. In Figure 2, the low-frequency band amplifier 10, the feedback resistor of the operational amplifier _{A 1,} resistor _{R 3} and the variable resistor VR ₁
By using an impedance element connected in series between the capacitors C ₁ and R ₄ and the semiconductor inductance L ₁ between the midpoint of the variable resistor VR ₁ and the ground, the amplification factor in a certain low frequency band Is made variable. This low frequency band amplifier 10 sets R ₁ : R ₂ = R ₃ : VR ₁ and then the transfer function T (s) is T (s) = {s ² + k (ω ₀ / Q) s + ω ₀ ² } / {s ² + (ω ₀ / Q) s + ω ₀ ² }. Note that k is a coefficient, ω ₀ is a resonance angular frequency, Q is a sharpness, and k = [R ₄ (R ₃ + VR ₁ ) + γ {(1-γ) × VR ₁ + R ₃ }] / {R ₄ ( R ₃ + VR ₁ ) + γ (1-γ) VR ₁ (R ₃ + VR ₁ )}. However, γ indicates the ratio of the resistance value between the midpoint and the ground with respect to the maximum value of the variable resistance VR ₁ .

In the adder 25, the non-inverting input terminal of the operational amplifier A ₃ is grounded, the feedback resistor R ₈ is provided between the output terminal and the inverting input terminal, the input resistor R ₆ and the resistor R ₇ are provided at the inverting input terminal, and the resistor R ₆ is provided. Since the signal of T (s) · e (t) is input via, the value of 1-α = R ₆ / R ₈ is set, while the signal of e (t) is input via the resistor R ₇ , By setting α = R ₇ / R ₈ , the resistors R ₆ , R ₇ , and R ₈ are determined and an inverted output is obtained.

The low-pass filter circuit 24 is composed of, for example, a series resistor R ₉ and a parallel capacitor C _3, and a circuit having a high-order filter characteristic is used when it is desired to sufficiently cut a high frequency component.

The subtractor 23 is provided with a feedback resistor R ₁₁ between the output terminal and the inverting input terminal of the operational amplifier A ₄ , and an input resistor R ₁₀ at the inverting input terminal. The output of the low-pass filter circuit 24 is provided at the non-inverting input terminal. Input and adder 2 to the inverting input terminal
The output of 5 is input.

The first power amplifier 21 and the second power amplifier 22 are configured to perform power amplification in phase with each other.

The speaker device 30 includes a mid-high range speaker 31 and a low-range speaker 32.

Then, one input end (+) of the mid-high range speaker 31 is connected to the first output terminal 21h (hot side terminal), and the other input end (-) is connected to the ground side terminal 21e of the first power amplifier 21, respectively. One of the input ends (+) of the bass speaker 32 is connected to the first output terminal 21h (hot side terminal).
The other input terminal (-) is connected to the second output terminal 22h (hot side terminal).

Now, assuming that the audio input signal is e (t), the low frequency band amplifier 10 amplifies a predetermined frequency band of the audio input signal e (t), and at the point a, T (s) · e ( t), and the adder 25 outputs (1-α) · T (s) · e
(T) and α · e (t) are added, and at point b, the output of − {α + (1-α) · T (s)} e (t) is obtained, and the low-pass filter circuit 24 transfers its transfer function. Let H (s) be the output of T (s) .H (s) .e (t) at point c, and subtracter 23 subtracts the signal at point b from the signal doubled at point c. Then, at the point d, the output of [2T (s) · H (s) + {α + (1-α) · T (s)} · e (t) becomes, and the first power amplifier 21 outputs the signal at the point b. Is amplified A times to supply power to the mid-high range speaker 31, and the second power amplifier 22 power-amplifies the signal at the point d to A times and A · [2T (s) · H (s) + { The output becomes α + (1-α) · T (s)} · e (t), and the hot side terminal 21h of the output of the first power amplifier 21 and the hot side terminal 2 of the output of the second power amplifier 22 are output.
During 2 h, the output of −2 · A · T (s) · H (s) · e (t) is obtained and power is supplied to the bass speaker 32.

That is, the bass speaker 32 is supplied with a signal in which the low-frequency band is enhanced and expanded and the high-frequency band is cut, so that the reproduced sound of the bass speaker 32 does not include a high-frequency component sound, and high-quality sound is obtained. .

In the embodiment, the adder 25 is configured so that the input and output phases are inverted. However, when the input and output of the adder 25 are configured to have the same phase, a well-known phase inversion is applied to the output. Needless to say, it is sufficient to connect a container.

Effect of the Invention: The loudspeaker of the present invention can inexpensively expand and enhance the low frequency range, and can provide a loudspeaker with excellent sound quality because the reproduced sound of the bass speaker 32 does not include the high frequency component sound. Becomes

[Brief description of drawings]

FIG. 1 is a circuit block diagram for explaining the present invention, FIG. 2 is a circuit block diagram for an embodiment of the present invention, and FIG. 3 is a block diagram for explaining a conventional example. 10 ... Low frequency band amplifier, 21 ... First power amplifier,
22 ... Second power amplifier, 23 ... Subtractor, 24 ... Low-pass filter circuit, 25 ... Adder, 30 ... Speaker device, 31 ... Mid-high range speaker, 32 ... Bass speaker, A ₁ , A ₂ , A ₃ , A ₄ ... Respective operational amplifiers, C ₁ , C ₂ , C ₃ ... Respective capacitors, L ₁ ...
... semiconductor _{inductance, R 1, R 2, R} 3 ‥, R 11
...... Resistors, VR ₁ …… Variable resistors.

Claims (1)

[Scope of utility model registration request] 1. A low frequency band amplifier (10) for amplifying a low frequency component of an audio input signal, a signal obtained by multiplying the audio input signal by α (where 0 <α <1), and the low frequency band amplifier (10). And a signal obtained by adding the signal obtained by multiplying the output of (1−α) to the inverted output, and the adder (2)
5) A first power amplifier (21) that power-amplifies the output, a low-pass filter circuit (24) that blocks high-frequency components of the output of the low-frequency band amplifier (10), and the output of the low-pass filter circuit (24) is doubled. A subtraction circuit (23) for subtracting the output of the adder (25) from the generated signal, and a second power amplifier (2 for power amplifying the output of the subtractor (25).
2), a first output terminal (21h) connected to the output of the first power amplifier (21), and the second power amplifier (22)
A second output terminal (22h) connected to the output, a bass speaker (32), and a mid-high range speaker (31) are provided, and one input end of the mid-high range speaker (31) is the first One output terminal (21h) is connected to the other input terminal to the ground, and one input terminal of the bass speaker (32) is connected to the first output terminal (21h) and the other input terminal is connected to the second input terminal. A loudspeaker, which is connected to each of the output terminals (22h).