JPH0744757B2 - Audio signal attenuator - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention processes a stereo signal during reproduction of a tape, record, compact disc, video disc or the like or reception of a radio, television, etc. The present invention relates to an audio signal attenuating device that attenuates components with respect to an accompaniment signal level to facilitate singing practice.

Conventional techniques To listen to and practice songs, it is often the case that various recording media are played back or television or radio is received. In many of these recording media, the singing voice and accompaniment of a professional singer are mixed and recorded. Similarly, singing voice and accompaniment are included in radio and television broadcasting. When practicing singing through these media, it is easy to practice because the voice of a professional singer is included because I am not used to it at first, but as I get used to it, I want to sing only with an accompaniment. In this case, the singing voice of a professional singer rather hinders practice.

As one method of achieving this, a tape commonly called "Karaoke" is commercially available. This is an accompaniment only, or the singing voice and accompaniment of a professional singer are recorded separately. However, these may take a long time from the release of a new song to the market, and it may be difficult to match it to your taste.

In order to satisfy the above needs, the following sound attenuator has been conventionally available. Hereinafter, description will be given with reference to the drawings. FIG. 2 shows an example of a conventional audio signal attenuator.

1 is one input terminal, 2 is the other input terminal, 3 is the first delay means, 4 is the second delay means, 5 is the subtraction section, 6 is the bass detection section, 7 is the mixing section, and 8 is the output terminal. Is. The first delay means 3 is, for example, a delay device 3 using an electronic delay element “bucket brigade device” (hereinafter abbreviated as BBD) or the like.
01 and an oscillator 302 that generates a clock signal. The second delay means 4 comprises a delay device 401, an oscillator 402, and a variable resistor 403 for adjusting the oscillation frequency. And
The delay device 401 uses the same type of BBD as the delay device 301.
The subtraction unit 5 is composed of a subtractor 501 using an operational amplifier. The bass detection unit 6 is composed of an adder 601 using an operational amplifier and a low pass filter 602.

The operation of the conventional audio attenuating apparatus thus configured will be described. The signal obtained when playing back a recording medium is a stereo signal, and the signal contains a voice and accompaniment such as a singing voice, and the audio signal is basically the same phase and amplitude for each stereo signal. Limited to those recorded in. One of the stereo signals is supplied to one input terminal 1 and the other signal is supplied to the other input terminal 2.
The signal at one input terminal 1 is delayed by the first delay means 3 for a fixed time. The delay time t _d is the BBD forming the delay unit 301.
Is determined by the number of stages N and the oscillation frequency _{c of the} oscillator 302, and the value can be calculated by the following equation.

t _d = N / (2 _c ) ... (1) The signal at the other input terminal 2 is delayed by the second delay means 4, and the value t _d ′ is the number of BBD stages N ′ oscillator 402 of the delay unit 401.
Can be calculated by the oscillation frequency _c ′ of

t _d ′ = N ′ / (2c ′) (2) Then, the delay time t _d ′ changes the oscillation frequency _c ′ by the adjustment of the variable resistor 403, and as a result, this can also be changed. .

In this way, the purpose of adjusting the delay time t _d ′ is to input terminal 1
And to compensate for the phase or time shift of the stereo signal applied to the input terminal 2. That is, the stereo signal recorded on the recording medium has a phase different from the original state due to instability factors of the reproducing means (not shown) and product variations even if the audio signals are recorded with the same phase and same amplitude. ing. In particular, when the cassette tape is reproduced, the phase shift of the audio signal is large due to factors such as instability of the running system and variations in the halves containing the cassette tape. The higher the recording frequency, the larger the phase shift. Therefore, it becomes difficult to attenuate the audio signal even if the arithmetic processing described later is performed. In order to prevent this state, the delay time is adjusted by the second delay means 4 so that the audio signals of the stereo signal are compensated so as to have the same phase.

The output of the first delay means 3 and the output of the second delay means 4 are subtracted by the subtraction unit 5. Now, assuming that the output of the first delay means 3 and the output of the second delay means 4 have the same audio signal phase and the same level, the audio signal is not output at the output of the subtractor 501. However, the accompaniment signal is generated as an output of the subtractor 501 because it is a stereo signal and has different phase and amplitude. Of the accompaniment signals, musical instruments with low frequency components, such as drum and bass signals, often have the same magnitude and phase even if they are stereo signals (the lower the frequency, the less the directivity). It may not be possible to record separately as stereo when recording). Therefore, the output of the subtractor 501 has less low-frequency components of accompaniment.

The bass detector 6 compensates for this low-frequency component.
The output of the first delay unit 3 and the output of the second delay unit 4 are added and calculated by the adder 601, and an accompaniment sound having a frequency lower than the audio frequency band is extracted by the low pass filter 602.

Next, the mixing unit 7 mixes the output of the subtraction unit 5 and the output of the low-pitched sound detection unit 6 and outputs the mixed result to the output terminal 8. Therefore, the user can listen to the sound with the loudspeaker (not shown) connected to the output terminal 8 and adjust the variable resistor 403 to set the sound to the minimum level so that only the accompaniment sound can be heard. Is.

Problems to be Solved by the Invention By the way, in addition to stereo signals, many recording media are output in a signal format called a monaural signal. A monaural signal has two or more output signal lines like a stereo signal, but the signals output to these plurality of output signal lines are the same including a voice signal and an accompaniment signal. The signals output to the output signal lines are mutually related but independent of each other, that is, the audio signals are common to the output signal lines but the accompaniment signals are different, which is a big difference. .

In such a monaural signal, the signal level of each output signal line is almost the same and the phases are almost the same, so in the conventional audio signal attenuator, the input signal is the audio signal in the subtraction unit 501. ， Because both accompaniment signals are canceled, the output of the subtraction unit 501 is always almost no signal,
Only the low-frequency component of the input signal extracted by the low-frequency detector 6 is output to the output terminal 8 through the mixing means 7, and the user can hear only the low-frequency component, which cannot be used for practicing a song. There is a problem of becoming.

In view of the above problems, the present invention detects whether an input signal is in a monaural signal format or a stereo signal format, and in the case of a stereo signal format, an audio signal is attenuated by the method described in the conventional example. It outputs a signal, but when it is a monaural signal, it outputs a signal that attenuates the audio signal by a method different from the conventional example. The resulting audio signal attenuator is provided.

Means for Solving the Problems In order to solve the above problems, the audio signal attenuating device of the present invention has a detecting means for detecting the fact that the input signal is in a monaural signal format, and a sound even in the monaural signal. A second attenuator that uses a method different from the conventional example for attenuating the signal to extract a signal mainly composed of an accompaniment signal, and an output of the second attenuator when receiving the output of the detector and a monaural signal And an output signal switching means for outputting a signal.

The audio signal attenuating device of the present invention couples the detecting means to the input signals of a plurality of channels and the output of the second adding means for adding the input signals, and the detecting means determines whether or not the input signal is in monaural form. Is detected and whether the output of the first attenuating means or the output of the second attenuating means is used as the output of the audio signal attenuating device is determined, and this output signal switching is performed by the output signal switching means. ing. Therefore, if the input signal is a stereo signal, the output signal is a signal in which the audio signal is attenuated by subtracting the output signals of the two delay means by the first attenuating means, but if the input signal is a monaural signal, the output signal is Can realize a new function of being automatically switched to the output signal of the second attenuator.

Embodiment An audio signal attenuating device according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an audio signal attenuator according to an embodiment of the present invention.

Reference numeral 1 is an input terminal to which signals associated with the accompaniment and voice and related to each other, for example, one of stereo signals are supplied, and 2 is an input terminal to which the other signal is supplied. Reference numeral 3 is a first delay means, which is composed of a delay device 301 and an oscillator 302 for generating its clock. For the delay device 301, an electronic delay element called “bucket brute device” (hereinafter abbreviated as BBD) is used as an example. A second delay means 4 is composed of a delay device 401, an oscillator 402 for generating a clock, and a variable resistor 403 for changing the frequency of the oscillator 402. As the delay device 401, BBD is used as in the delay device 301.

Reference numeral 9 is a first attenuator, which is a subtracter using an operational amplifier.
Consists of 901. Reference numeral 10 is a first adding means, which is composed of an adder 101 using an operational amplifier. Reference numeral 11 is a low-pitched sound extraction means, which is composed of a low-pass filter 111. Reference numeral 12 is a mixing means, which is configured by applying an operational amplifier. Reference numeral 13 is a second adding means for adding the input signals inputted to the input terminals 1 and 2, and is an adder 130 using an operational amplifier.
It consists of. Reference numeral 14 is a detection means, which is configured by applying an operational amplifier, an AD converter, a microcomputer, and the like. 15
Is a second attenuator, which is composed of a band elimination filter 151 using an operational amplifier. Reference numeral 16 is an output signal switching means, which is configured by using an analog electronic switch or relay to which FET is applied. Reference numeral 17 denotes an output terminal for outputting a signal obtained by attenuating a voice signal to a device (not shown) such as a loudspeaker.

The operation of the audio signal attenuator configured as above will be described.

First, the input signal will be described. When a voice signal such as a singing voice of a professional singer and an accompaniment signal such as a musical instrument are combined and are related to each other, for example, a stereo signal is used as an input signal of this device. Recently, signals of a plurality of channels such as four channels may be used as one of three-dimensional sound reproduction means, but these are also included in the stereo signal.

By the way, generally, in the stereo system, an audio signal is often formed with the same phase and the same amplitude between two signals. This is because when the phase or amplitude of the audio signal is different or changes between the two signals, the sound image of the audio is not localized in the center in stereo reproduction and is reproduced at a position where it moves to one of the two. It causes a problem that the position changes unstablely. Further, when the stereo signal is reproduced in monaural, the audio signal may be canceled out and the audio signal may be smaller than the original size. On the other hand, the accompaniment signal is often formed such that different instrument signals are inserted between two stereo signals in order to give a sense of reality.

When reproducing this stereo signal from the recording medium or receiving the broadcast radio wave, a time difference different from the original state occurs between the two signals of the stereo signal reproduced due to the performance difference, variation, and instability factor of the equipment. The amplitude level may change as the phase difference occurs. For example, when a cassette tape is reproduced by a tape recorder, a time lag of an audio signal between two stereo signals occurs at a maximum of 200 microseconds to 300 microseconds.

If there is such a time difference, it becomes difficult to attenuate the audio signal from the stereo signal. To compensate for this, the first delay means 3 and the second delay means 4 perform time alignment, that is, phase control. Then, the sound signal level is attenuated by the subsequent arithmetic processing.

Next, detailed operation of each unit will be described. First delay means 3
One of the stereo signals supplied to the
Delayed by 1. The delay time t _d is calculated by the following equation based on the number N of BBD stages forming the delay device 301 and the oscillation frequency _c of the oscillator 302.

t _d = N / (2 _c ) ... (3) Also, the other signal of the stereo signals is supplied from the input terminal 2 to the second delay means 4 and is delayed there. The delay time t _d ″ can be calculated by the following equation using the number of stages B ″ of the BBD configuring the delay unit 401 and the oscillation frequency _c ″ of the oscillator 402.

t _d ″ = N ″ / (2 _c ″) (4) The relative relationship between the oscillation frequency and the delay time is as follows.

However, N = N ″.

That is, by changing the equation (5), (6), (7) a first delay time of the delay time of the delay means 3 t _d with respect to the second delay means 4 t _d "as shown in the formula It is possible to use two of the stereo signals generated by the reproducing means and the receiving device.
The time lag between two signals (hereinafter abbreviated as channel time difference) is t ₀ with reference to the signal supplied to the input terminal 1, and a relationship such as t ₀ = t _d −t _d ″ (8) is established. If t _d ″ is adjusted so that it holds, the original phase or time relation of the steres signal can be restored.

That is, in a means for reproducing a recording medium (for example, tape or disk) or a means for receiving broadcast radio waves (for example, radio or television), between the plurality of channel outputs (stereo output) depending on the performance of the device, unstable factors, etc. Even if there is a steady phase difference or time difference, it can be corrected by adjusting the variable resistor 403. Therefore, the output of the first delay means 3 and the output of the second delay means 4 have the same phase or time relationship as when recording on the recording medium, and the audio signal components have the same phase. ing.

The first attenuating means 9 receives the outputs from the first delaying means 3 and the second delaying means 4, respectively, and performs a subtraction arithmetic process on these outputs. For example, when subtraction is performed by the subtractor 901, the signal of the in-phase component does not appear in the output, but the component of different phase appears as the output. Therefore, the audio signal components having the same phase are attenuated or deleted to zero by the subtractor 901, and accompaniment signal components having different phases are generated as the output of the subtractor 901. That is, the sound signal attenuation function is realized.

The first adding means 10 receives the outputs of the first delaying means 3 and the second delaying means 4 and performs addition arithmetic processing in the adder 101.

The bass extraction unit 11 uses a low-pass filter 111 to extract an accompaniment signal having a low frequency component (for example, 100 hertz or less). The purpose of this is that when the subtraction operation is performed by the attenuating means 9, the audio signal component of the same phase is attenuated, but the accompaniment component of the low frequency component of 100 hertz or less is also likely to be attenuated due to the small phase difference, and compensation for this Is to do. That is,
The low-pass filter 111 extracts the low-frequency component of the accompaniment signal output from the first adding means 10, and the mixing means 1
At 2 it is mixed with the output of the damping means 9. As a result, an accompaniment signal in which the audio signal component is attenuated or deleted is generated at the output of the mixing means 12. The second adding means 13 is for adding input signals of a plurality of channels, and when the input signals have the same amplitude and the same phase, it outputs a signal having an amplitude twice that of the input signal.

The detection means 14 detects whether the signals input to the input terminals 1 and 2 are stereo signals or monaural signals based on the output signal of the second addition means 13 and the input signals of a plurality of channels. Then, the signal whose type has been detected is output to the output signal switching means 16. In the present embodiment, when the magnitude of the output signal of the second adding means 13 becomes a signal level which is twice the level of the input signals of a plurality of channels, it is assumed that the input signal is a monaural signal. Details of the detecting means 14 will be described later.

The second attenuator 15 uses the band elimination filter 151 to attenuate a voice signal component having a frequency band of hundreds of hertz to several kilohertz of the output signal of the adder 10 to obtain a signal mainly composed of an accompaniment signal component. To do.

In addition to the operation explanatory view of the second damping means in FIG.
The operation of the attenuator 15 will be described in more detail.

The input signal of the second attenuator 15, that is, the input signal of the band elimination filter 151 will be described as having a frequency spectrum as shown in FIG.

As shown in FIG. 3A, the input signal of the band elimination filter 151 is set to a region of a bass accompaniment signal whose frequency is several hundred hertz or less,
It is roughly classified into a region in which a sound signal having a frequency of several hundreds of hertz to several kilohertz and a mid-range accompaniment signal are mixed, and a region of a high-range accompaniment signal having a frequency of several kilohertz or more. It suffices if only the audio signal component of such an input signal can be removed. However, since the actual frequency characteristic of the band elimination filter has a certain frequency elimination characteristic as shown in FIG. 3b, the output signal of the band elimination filter 151 is shown in FIG. 3c.
As described above, the audio signal is greatly attenuated, but the mid-range accompaniment signal is also greatly attenuated, and the bass range accompaniment signal and the treble range accompaniment signal are partially removed, and the sound quality deteriorates to some extent.

Unlike the method using the band elimination filter, the method of subtracting the two delay means used in the first attenuating means has the great advantage that the accompaniment sound is less deteriorated, but when the input signal is a monaural signal. Has the drawback that the accompaniment signal is also removed. It is an object of the present invention to try to make up for the drawback of the first attenuating means by the second audio attenuating means that can be used even if the input signal is a monaural signal, although the sound quality is deteriorated to some extent.

The output signal switching means 16 receives the output signal of the detection means 14,
If the detection means 14 determines that the input signal is a stereo signal, the output signal of the mixing means 12 is switched to the output terminal 17 as an audio signal attenuator, and,
If the detecting means 14 determines that the input signal is a monaural signal, the output signal of the second attenuating means 15 is switched to the output terminal 17.

Now, the detecting means 14 will be described in detail with reference to FIGS. 4 and 5.

FIG. 4 is a concrete circuit configuration diagram of the detection means 14, and 131 is an input terminal for inputting an L channel input signal which is one of a plurality of channels of input signals (here, stereo 2 channel signals), 132 is an input terminal for inputting the R channel input signal which is the other signal of the input signals of a plurality of channels, 133 is an input terminal coupled to the output of the second adding means 13, 134-136 are operational amplifiers, and 137-139 are Diode, 14
0 to 142 are resistors, 143-145 are capacitors, 146-148 are AD
A converter, 149 is a microcomputer, and 150 is an output terminal coupled to the output signal switching means 14.

Operational amplifier 134, diode 137, resistor 140, capacitor 14
3 is for rectifying the L channel input signal and converting the magnitude of the signal into the magnitude of the DC voltage. The AD converter 146 converts the DC voltage representing the magnitude of the signal into a digital signal to input the L channel. The signal level is output to the microcomputer 149 as a digital signal. Similarly, the operational amplifier 135, the diode 138, the resistor 141, the capacitor 144, and the AD converter 147 provide the output of the AD converter 147 with the level of the R channel input signal as a digital signal. Is output to. or,
Operational amplifier 136, diode 139, resistor 142, capacitor 14
5. The AD converter 148 obtains, as the output of the AD converter 148, a digital signal whose level is the output signal of the second adding means 13 and outputs the digital signal to the microcomputer 149.

The microcomputer 149 determines whether or not the plurality of input signals are monaural signals by processing the digital signals which are the output signals of the AD converters 146 to 148, and outputs the result to the output terminal 150. is there.

The operation of the microcomputer 150 will be described below with the flowchart of the microcomputer shown in FIG.

It is assumed that the microcomputer 149 has been powered on and has completed the reset operation and memory erase operation necessary for processing. First, in step 21, the memory T for counting the amount of time is set to 0. Next, in step 22, the output signal of the AD converter 146 and the output signal of the AD converter 147 are compared to determine whether the output signals of these two AD converters are substantially the same, that is, the input signals of a plurality of channels are It is determined whether or not the signal levels are substantially the same, and if the levels are significantly different, step 22 is repeated, and if the levels are substantially the same, step 23 is repeated.
Go to.

In step 23, the output signal of the AD converter 148 is compared with the output signal of the AD converter 146 or the output signal of the AD converter 147, and the output signal of the second adding means 13 is almost 2 times the input signals of the plurality of channels. It is judged whether or not the signal level is doubled, and if the size is almost doubled, it can be judged that the input signal is a stereo signal. Therefore, the memory T is set to 0 in step 24, and output to the output terminal 17 in step 25. As the signal, a signal for selecting the audio attenuation signal which is the output of the mixing means 12 is output to the output terminal 150 of the microcomputer 149, and the process returns to step 22. On the contrary, if it is determined in step 23 that the output signal of the second adding means 13 has a signal level almost twice as high as the input signal of the plurality of channels, the value of the memory T is set to 1 in step 26.
Then, in step 27, it is determined whether or not the value of the memory T is equal to or larger than a certain constant K value. This step 27
Even if the input signal is a monaural signal, the judgment at is not to switch the output signal to the output terminal 17 immediately after it is detected as a monaural signal. That is, if the determination in step 27 is not made, the input signal may be a stereo signal depending on the track of the input signal, but may be determined to be a monaural signal at a certain time point and a stereo signal at the next time point. As described above, the signal output to the output terminal 17 may be repeatedly switched in the same song. The reason is that even if the input signal is a stereo signal, if there is no accompaniment temporarily and there is only an audio signal, it will be in the same state as a monaural signal temporarily. Can happen.

The determination at step 27 is made by comparing the value in the memory T with the constant K to determine whether or not a sufficient time, for example, 5 seconds has elapsed since the input signal became a monaural signal. The constant K is set to a value that can be regarded as sufficient time after the above monaural signal is obtained. If it is determined in step 27 that a monaural signal has been obtained and sufficient time has passed, the process proceeds to step 28, and a signal for selecting the output signal of the second attenuating means as the output signal to the output terminal 17 is output to the output terminal of the microcomputer 149. Output to 150 and return to step 22.

Next, the operation of the entire apparatus will be described. In FIG. 1, the user reproduces a stereo signal by reproducing means (not shown), supplies those signals to the input terminals 1 and 2, and listens to the signal at the output terminal 17 with a loudspeaker (not shown). And Then, it is assumed that the audio signal component of the stereo signal is recorded in the recording medium (not shown) in the same phase and the same amplitude between the respective channels. In this state, the variable resistor 403 is adjusted so that the audio signal component becomes the minimum state. That is, even if the phase of the audio signal component of the stereo signal applied to the input terminals 1 and 2 is different due to the performance or variation of the reproducing means, the delay action of the first delay means 3 and the delay action of the second delay means 4 are performed. By
The audio signal components at the output of the first delay means 3 and the output of the second delay means 4 can have the same phase.

The first attenuating means 9 performs subtraction (or difference) between the output of the first delay means 3 and the output of the second delay means 4 by a subtractor 901, and the output thereof is an audio signal component having the same phase relationship. Is greatly attenuated, and accompaniment signal components having different phase relationships are generated. That is, the damping action of the audio signal is realized.

In the first attenuator 9, the accompaniment signal component of the low frequency component may have a small phase difference and may be attenuated at the same time.
The accompaniment signal component extracted by the bass extraction means 11 and the output of the first attenuating means 9 are supplied to the mixing means so that the accompaniment signal can be brought closer to the original state.

When the signals input to the input terminals 1 and 2 are stereo signals, the two input signals usually have different levels and phases, the two input signal levels are different, and the output signal of the second adding means is 2 The detection means 14 sends a signal to the output signal switching means 16 so that the output signal of the mixing means 12 is output from the output terminal 17, because the signal level does not become almost twice as high as that of one input signal.

When the signals input to the input terminals 1 and 2 are monaural signals, the two input signal levels are substantially the same, and the output signal of the second adding means 13 is approximately twice as large as the two input signals. In order to obtain the signal level of
It operates so as to send a signal to the output signal switching means 16 so that the output signal of the second attenuating means 15 is output from the output terminal 17.

Although the BBDs are used for the delay units 301 and 401 in the embodiment of FIG. 1, the same operation can be realized by a digital memory (not shown). Also, the subtractor 901 and the adder 101
Also, an example in which an operational amplifier is applied to the mixing means 12 and a low-pass filter 111 is used for the bass extraction means 11 has been described, but the same operation can be digitally realized by using a microcomputer or the like.

In addition, although an example in which a microcomputer is used as the detection means is shown in the present embodiment, it is also possible to realize the same operation by combining an analog circuit and a general-purpose digital circuit without using such a microcomputer. is there.

Further, in the present embodiment, in the processing operation of the microcomputer as the detection means, it is determined whether or not a sufficient time has elapsed since the input signal became a monaural signal.
The sufficient time is not limited to 5 seconds mentioned in this embodiment, but may be shorter or longer, and the length may be changed depending on the case.

Further, in the present embodiment, the processing operation of the microcomputer as the detection means is such that even if the input signal is basically a stereo signal, if there is a part that becomes a monaural signal for 5 seconds or more, the monaural signal will be temporary. Therefore, the output of the audio signal attenuator is switched. In order to avoid this inconvenience, it is determined whether the input signal is a stereo signal or a monaural signal within a certain time of the beginning of the song, and this determination is not changed until the performance of the entire song is finished. Good.

Further, in this embodiment, the output signal of the first adding means is supplied as the input signal of the second attenuating means, but the input signal itself input from the input terminal, the output signal of the first delay means, It may be configured to supply either of the output signals of the two delay means.

Also, in this embodiment, three circuits including an AD converter are provided to detect the signal levels of the input signal input from the input terminal and the output signal of the second adding means.
It is also possible to detect three signal levels by time division processing for only the system.

EFFECTS OF THE INVENTION As described above, the present invention includes first delay means for delaying an input signal of one channel among input signals of a plurality of channels in which accompaniment music signals and audio signals are mixed and which are mutually related, A second delay means capable of delaying the input signal of the other channel and varying the delay time thereof, an output signal of the first delay means and an output signal of the second delay means, and subjecting them to an audio signal component. A first attenuating means for attenuating or deleting the signal, a first attenuating means for arithmetically processing the output signal of the first delay means and the output signal of the second delay means, and outputting an addition signal; Bass extraction means for extracting the accompaniment signal component in the low frequency region included in the output signal of the first addition means, and mixing means for mixing the output signal of the first attenuation means and the output signal of the bass extraction means, Previous Note that the input signal is a monaural signal based on the second adding means for adding the input signals of the plurality of channels, and the level of the output signals of the plurality of channels and the level of the output signal of the second adding means. Detecting means for detecting whether or not the result is outputted, second attenuating means for attenuating or deleting an audio signal component by processing the output signal of the first adding means by a filter circuit, and the detecting means. Output signal switching means for automatically selecting and outputting either the output signal of the mixing means or the output signal of the second attenuating means in accordance with the output signal of As a result, it is possible to obtain a signal in which the sound signal is attenuated and the sound quality is mainly deteriorated with the accompaniment signal and the input signal is a monaural signal. A signal in which the audio signal is attenuated by a method other than the audio attenuation method at the time of signal is automatically selected.This allows the user to select the monaural signal format regardless of whether the output signal of the recording medium used is the stereo signal format. It has an excellent effect that you can practice singing without worrying about it.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an audio signal attenuating device of the present invention, FIG. 2 is a block diagram of a conventional audio signal attenuating device, and FIG. 3 is an operation explanatory view of a second attenuating means. FIG. 5 is a concrete circuit diagram of the detecting means, and FIG. 5 is a flow chart showing the main processing of the microcomputer. 3 ... First delay means, 4 ... Second delay means, 9 ...
1st attenuation means, 10 ... 1st addition means, 11 ... bass extraction means, 12 ... mixing means, 13 ... 2nd addition means, 14 ... detection means, 15 ... 2nd attenuation Means, 16 ... Output signal switching means.

Claims (1)

[Claims] 1. A first delay means for delaying an input signal of one channel among input signals of a plurality of channels in which accompaniment music signals and voice signals are mixed, and input signals of the other channel. Second delay means capable of delaying and delaying the delay time, and an output signal of the first delay means and an output signal of the second delay means are arithmetically processed to attenuate or delete an audio signal component. One attenuating means, the output signal of the first delay means and the second signal
First addition means for calculating the output signal of the delay means and outputting an addition signal, and bass extraction means for extracting the accompaniment signal component of the low frequency region included in the output signal of the first addition means. Mixing means for mixing the output signal of the first attenuating means and the output signal of the bass extracting means; second adding means for adding the input signals of the plurality of channels; and levels of the input signals of the plurality of channels. A detection unit that detects whether or not the input signal is a monaural signal based on the level of the output signal of the second addition unit and outputs the result, and an output signal of the first addition unit. Depending on the output signal of the detecting means and the second attenuating means for attenuating or deleting the audio signal component by processing the signal with a filter circuit. Either the output signal of the mixing means or the output signal of the second attenuating means. Automatically audio signal attenuation apparatus characterized by an output signal switching means for selecting output.