JPH05122796A - Acoustic effect controller - Google Patents

Abstract

PURPOSE:To change an acoustic effect by suppressing the generation of noise with simple construction. CONSTITUTION:A left sound signal (L signal) and a right sound signal (R signal) are supplied to a buffer 12, and the L signal is outputted to both adder 19 and switch 13. The R signal is outputted to subtracters 14 and 20. The output of the switch 13 is also supplied to the subtracter 14, thereby calculating the difference of two signals. The output of a subtracter 15 is phase-shifted by a phase shifter 15 to be supplied to a switch 17 after the high frequency component is eliminated by an LPF 16. The amplitude of the output of the switch 17 is attenuated by a variable attenuator 18 to be supplied to the adder 19 and the subtracter 20. A microcomputer 23 supplies control signals (a), (b), and (c) to the switches 13 and 17 and the variable attenuator 18 to control the operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound effect control device capable of switching sound effects, and more particularly to a sound effect control device which does not require a sound mute process at the time of sound effect switching.

[0002]

2. Description of the Related Art In a concert hall, a movie theater, etc., a sound in which a direct sound and a reflected sound reflected by a ceiling or a wall are superimposed reaches a listener's ear. Therefore, it gives a unique sound effect to humans. As a method to create this acoustic effect electrically,
There is a method of mixing the phase-shifted audio signal and the original audio signal.

A conventional acoustic effect control device will be described below with reference to the drawings. FIG. 3 is a configuration diagram showing a configuration of a conventional acoustic effect control device. In this figure, the left audio signal (L signal) is supplied to the buffer 12 via the terminal 10. Similarly, the right audio signal (R signal) is supplied to the buffer 12 via the terminal 11. Of the output of the buffer 12, the L signal is supplied to the adder 19 and the switch 13. The R signal is also supplied to the subtractors 14 and 20. The output of the switch 13 is also supplied to the subtractor 14, and the difference between the two signals is calculated. The output of the subtractor 14 is phase-shifted by a phase shifter 15 and high-frequency components are removed by an LPF (low-pass filter) 16, and then the switch 1
7 is supplied. The output of the switch 17 is attenuated in amplitude by the variable attenuator 18 and then supplied to the adder 19 and the subtractor 20. The adder 19 converts the L signal into the variable attenuator 18
Are added to the output of the terminal 21 via the mute circuit 25.
Will be output. On the other hand, the subtractor 20 subtracts the output of the variable attenuator 18 from the R signal, and outputs the subtracted signal from the terminal 22 via the mute circuit 25.

Further, the switches 13 and 17, the variable attenuator 1
8. Control signals a, b, c and d are supplied to the mute circuit 25 from the microcomputer 26, respectively, and their operations are controlled.

Next, the operation in FIG. 3 will be described. First,
In the case of normal stereo sound, the switch 17 is turned "OFF" by the control signal b. Therefore, the L and R signals output from the buffer 12 are output from the terminals 21 and 22 as they are. On the other hand, as a first acoustic effect, when mixing the signals in which the phase of the R signal is shifted with the L and R signals, the switch 17 is turned “ON”, but the switch 13 is turned “OFF” by the control signal a. Become. The variable attenuator 18 is controlled in its attenuation amount by the control signal c. The degree of the acoustic effect is controlled by this attenuation amount. As a result, the phase of the R signal is shifted and the attenuated signal is added to the L signal and output from the terminal 21. Also, the phase of the R signal is shifted and the attenuated signal is subtracted from the R signal,
It is output from 2.

The second acoustic effect is the switch 1
3 is set to "ON", an error signal corresponding to the difference between the L signal and the R signal is obtained, and after phase shift, the error signal is attenuated. This signal is mixed with the L and R signals and output from the terminals 21 and 22. As described above, it is possible to generate signals to which the first and second acoustic effects are applied in addition to the stereo sound.

However, when changing the type or degree of the acoustic effect, the DC offset fluctuates before and after the change, resulting in noise. Due to the price, in a sound effect control device that does not have an offset adjustment circuit, mute processing is performed before the change in order to suppress noise.
The mute process was canceled after the change. That is, when a change command is issued, the switch of the mute circuit 25 is turned off by the control signal d and then the change is made, and after the change is finished, the switch of the mute circuit 25 is turned on.

In the case of such a processing method, the music or voice output is interrupted every time the acoustic effect is changed. Further, a mute circuit 25 control unit is required inside the mute circuit 25 and the microcomputer 26 in order to suppress noise.

[0009]

When changing the type or degree of the acoustic effect, the DC offset fluctuates before and after the change, resulting in noise. Therefore, in order to suppress noise in a sound effect control device that does not have an offset adjustment circuit, mute processing is performed before the change,
The mute process was canceled after the change. With such a processing method, the output music or voice is interrupted each time the sound effect is changed. Further, a mute circuit 25 control unit is required inside the mute circuit 25 and the microcomputer 26 in order to suppress noise.

The present invention has been made in view of the above problems, and an object thereof is to provide a sound effect control device capable of changing a sound effect while suppressing noise generation with a simple structure.

[0011]

Means for Solving the Problems The means according to the present invention receives, as an input, any one signal of a left audio signal, a right audio signal, and a difference signal between left and right audio signals.
, A level shifter for adjusting the level of the first signal from the phase shifter, and the output of the level adjuster mixed with the left audio signal and the right audio signal. Mixing means and a first mode arranged on the input side or the output side of the level adjusting means for supplying the first signal to the mixing means, or a second mode for stopping the supply to the mixing means. When the switch means is operable and the switch means shifts from the second mode to the first mode, the output level of the level adjusting means is gradually decreased and then gradually increased to the original level. By including the control means for controlling so as to recover, noise generated when changing the sound effect can be suppressed.

[0012]

In a configuration in which a sound effect is obtained by inputting one of the left and right sound signals or a difference signal between them, adjusting the level after phase shifting, and mixing with the left and right sound signals, before switching the sound effect. By reducing the level of the mixed signal and increasing the level after switching, noise generated when changing the sound effect is suppressed.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing the configuration of the present invention,
FIG. 2 is an explanatory diagram for explaining the operation in FIG. still,
The same numbers are attached to the same components as the conventional ones.

In FIG. 1, the left audio signal (L signal) is supplied to the buffer 12 via the terminal 10. Similarly, the right audio signal (R signal) is supplied to the buffer 12 via the terminal 11. Of the output of the buffer 12, the L signal is supplied to the adder 19 and the switch 13. The R signal is also supplied to the subtractors 14 and 20. The output of the switch 13 is also supplied to the subtractor 14, and the difference between the two signals is calculated. The output of the subtracter 15 is phase-shifted by the phase shifter 15, the high frequency components are removed by the LPF 16, and then the output is supplied to the switch 17. The output of the switch 17 is attenuated in amplitude by the variable attenuator 18 and then added by the adder 1
9 and the subtractor 20. The adder 19 adds the output of the variable attenuator 18 to the L signal and outputs the result from the terminal 21. On the other hand, the subtracter 20 converts the R signal from the variable attenuator 1
The output of 8 is subtracted and output from the terminal 22.

Switches 13, 17 and variable attenuator 18 are also provided.
The control signals a, b, and c are supplied to each of the microcomputers 23 to control their operations.

Next, the operation will be described with reference to FIG. First, in the case of normal stereo sound, the switch 17 is turned "OFF" by the control signal b. Therefore, the L and R signals output from the buffer 12 are output from the terminals 21 and 22 as they are. On the other hand, as a first acoustic effect, when mixing the signal in which the phase of the R signal is shifted with the L and R signals, the switch 17 is turned “ON”, but the switch 13 is turned “OFF” by the control signal a. Become. Variable attenuator 1
The attenuation amount of 8 is controlled by the control signal c. The degree of the acoustic effect is controlled by this attenuation amount. This makes R
The phase of the signal is shifted and the attenuated signal is added to the L signal and output from the terminal 21. Further, the phase of the R signal is shifted and the attenuated signal is subtracted from the R signal and output from the terminal 22.

The second acoustic effect is the switch 1
By setting 3 to "ON", an error signal corresponding to the difference between the L signal and the R signal is obtained, which is attenuated after the phase shift. This signal is mixed with the L and R signals and output from the terminals 21 and 22. As described above, it is possible to generate signals to which the first and second acoustic effects are applied in addition to the stereo sound.

By the way, when changing the type and degree of the acoustic effect, the attenuation amount in the variable attenuator 18 is gently attenuated before the change and is gradually returned to the original value after the change, or is adjusted to the changed attenuation amount. Done. This state is shown in FIG.

In FIG. 2, the vertical axis represents the output level of the variable attenuator 18, and the horizontal axis represents time. In this figure, if a sound effect change command is issued at time t1, the output level is gradually reduced by the control signal c after t1. Then, the change is made at the time t2, and thereafter the output level is gradually returned to the original level. Then, at time t3, the changing process ends.

By such processing, the fluctuation of the DC offset at the time of change can be suppressed to a small level.
The noise generated by offset variations is so small that it is not noticed. Further, since the audio signal is output without interruption, it is possible to make a change without a feeling of strangeness. When compared with the conventional example, the sound effect can be controlled by the microcomputer 23 that does not require the mute circuit 25 control unit inside the mute circuit 25 and the microcomputer 26.

The switch 17 is the LPF 1 in FIG.
It may exist at the point A instead of between 6 and the variable subtractor 18. Further, although one of the R signal and the error signal is selected in the present invention, one of the L signal and the error signal may be selected, or one of the R signal, the L signal and the error signal may be selected. May be selected.

[0022]

When the type or degree of the acoustic effect is changed, the attenuation amount in the variable attenuator 18 is gently attenuated before the change and is gradually returned to the original value after the change, or is adjusted to the changed attenuation amount. Is done. As a result, the fluctuation of the DC offset at the time of change can be suppressed to a small level, and the noise generated by the offset fluctuation can be made too small to be detected. Further, since the audio signal is output without interruption, it is possible to make a change without a feeling of strangeness.
When compared with the conventional example, the sound effect can be controlled by the microcomputer 23 that does not require the mute circuit 25 control unit inside the mute circuit 25 and the microcomputer 26.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a configuration of the present invention.

FIG. 2 is an explanatory diagram explaining an operation in FIG.

FIG. 3 is a configuration diagram showing a conventional configuration.

[Explanation of symbols]

 12 ... Buffer 13, 17 ... Switch 15 ... Phase shifter 18 ... Variable attenuator 23 ... Microcomputer

Claims (1)

[Claims] 1. A phase shift circuit which inputs any one of a left audio signal, a right audio signal, and a difference signal between left and right audio signals and outputs a phase-shifted first signal, and from this phase shift circuit Level adjusting means for adjusting the level of the first signal, mixing means for mixing the output of the level adjusting means with the left audio signal and the right audio signal, and an input side or an output side of the level adjusting means. Switch means arranged and operable in a first mode for supplying said first signal to said mixing means or in a second mode for stopping the supply to said mixing means, said switch means comprising said second means. When the mode is shifted to the first mode, the output level of the level adjusting means is gradually decreased and then gradually increased to return to the original level. Sound effect control device, characterized in that the.