JPH062396Y2 - 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. 4 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] The loudspeaker shown in FIG. 4 requires two identical low frequency band amplifiers 1 and 2, and also has two volumes for adjusting the amplification degree of the low frequency band. You need what you let. 2ch
In the case of stereo, four low frequency band amplifiers and four volumes are required, which increases the number of parts and increases the cost. Further, when the frequency bands of the low-frequency band amplifier 1 at the front stage and the low-frequency band amplifier 2 at the rear stage deviate due to variations in component constants or the like, it becomes difficult to obtain the predetermined characteristics in the bass speaker.

The present invention has been made in view of the above points, and was made as an attempt to provide a loudspeaker capable of expanding and enhancing the low frequency range at low cost.

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 the first power amplifier 21 for amplifying the output of the low frequency band amplifier 10 and the output of the low frequency band amplifier 10 by α (where 0 <α
<1) The multiplied signal and the audio input signal are (1-
α) adder 23 for adding the multiplied signal and the adder 2
A phase inverter 24 that inverts the phase of three outputs, a second power amplifier 22 that power-amplifies the output of the phase inverter 24, and a first output terminal 21 that is connected to the output of the first power amplifier 21.
h and 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, and one input end of the mid-high range speaker 31 has the second output. The other input end of the terminal 22h is connected to the ground side terminal 22e of the second power amplifier 22, and one input end of the bass speaker 32 is connected to the second end of the second power amplifier 22.
The other input end is connected to the output terminal 22h and the first output terminal 2
It is a loudspeaker connected to each 1h.

[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. The low frequency band amplifier 10 sets R ₁ : R ₂ = R ₃ : VR ₁ and 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 .

The adder 23 is such that the non-inverting input terminal of the operational amplifier A ₃ is grounded, and the feedback resistor R ₈ is provided between the output terminal and the inverting input terminal, and the input resistance R ₆ and the resistor R ₇ are provided at the inverting input terminal. , One of the input signals of the adder 23 is α · e (t)
Therefore, α = R ₆ / R ₇ and the other input signal is (1−α) · e (t). Therefore, 1−α = R ₈ / R _{6 so} that the resistors R ₆ , R ₇ , R ₈ is set to obtain an inverted output. That is, the adder 23 of this embodiment has an addition function of multiplying an input signal by a predetermined constant and then adding the two signals together with a phase inverting function of inverting the phase of the signal between the input and the output.

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 second output terminal 22h (hot side terminal), and the other input end (-) is connected to the ground side terminal 22e of the second power amplifier 22, respectively. And one input end (+) of the bass speaker 32 is connected to the second output terminal 22h (hot side terminal),
The other input terminal (-) is connected to the first output terminal 21h (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 T (s) · e (t ) Is output, and the power is further amplified by the first power amplifier 21 to become an output of T (s) · A · e (t) at point b. The adder 23 adds αT (s) e (t) and (1-α) e (t) and outputs the inverted signal. At point c,-{αT (s) + The output is (α + 1)} × e (t), and the power is further amplified in phase by the second power amplifier 22. At point d, −A {α · T (s) + (α + 1)} · e ( t) is obtained and the speaker 31 for middle and high frequencies is driven. 2A × [s ² + {k + 1 + α (k−1)} / 2 × (ω ₀ / Q) between the second output terminal 22h of the second power amplifier 22 and the first output terminal 21h of the first power amplifier 21. s + ω ₀ ² ] / {s ² + (ω ₀ / Q) s + ω ₀ ² } × e (t), and the low-frequency speaker 32 is set to {k + 1 + α (k-1)} / 2 at the angular frequency ω ₀ . It will be doubled and driven.

As described above, the loudspeaker according to the embodiment of the present invention can extend and enhance the low frequency band.

In the embodiment, the adder 23 is configured so that the input and output phases are inverted so that the action of the phase inverter is also provided. However, the input and output of the adder 23 are in phase. In the case of such a configuration, it goes without saying that a known phase inverter may be connected to the output.

Effect of the Invention: The loudspeaker of the present invention can extend and enhance the low frequency band, and instead of using two low frequency band amplifiers 1 and 2,
By providing the individual low frequency band amplifiers 10 and the adder 23, which is cheaper than the low frequency band amplifiers 10, the cost becomes low.

[Brief description of drawings]

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, FIG. 3 is a characteristic diagram of a low frequency band amplifier 10, and FIG. 4 is a block for explaining a conventional example. Fig. 10 ... Low frequency band amplifier, 21 ... First power amplifier, 22
Second power amplifier, 23 Adder, 24 Phase inverter,
30 ... Speaker device, 31 ... Mid-high range speaker, 32 ...
Bass speakers, A ₁ , A ₂ , A ₃ ... Operational amplifiers, C ₁ , C ₂ , C ₃ ... Capacitors, L ₁ ... Semiconductor inductances, R ₁ , R ₂ , R ₃ ..., R ₈ ... Respective resistors Variable resistor, VR ₁ ... Variable resistor.

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 first power amplifier (21) for power amplifying an output of the low frequency band amplifier, and the low frequency band amplifier (10). An adder (23) for adding a signal obtained by multiplying the output by α (where 0 <α <1) and a signal obtained by multiplying the audio input signal by (1-α), and inverting the phase of the output of the adder (23). A phase inverter (24) and a second power amplifier (2) that power-amplifies the output of the phase inverter (24).
2), a first output terminal (21h) connected to the output of the first power amplifier (21), a second output terminal (22h) connected to the output of the second power amplifier (22), and a bass speaker ( 32) and a mid-high range speaker (31),
One input end of the mid-high range speaker (31) is connected to the second output terminal (22h) and the other input end is connected to the ground, respectively, and one input end of the low-range speaker (32) is connected to the above-mentioned one. A loudspeaker device characterized in that the other input end of the second output terminal (22h) is connected to the first output terminal (21h).