JPH071597B2 - 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 301 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 detector 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,
The value can be calculated by the following formula.

_{t d = N / (2 c} ) .................. (1) the other input terminal 2 of the signal is delayed by the second delay unit 4, the delay t _'d is the number of stages of BBD delay units 401 N can be calculated by _c ', oscillation frequency of the oscillator 402'.

_{t 'd = N' / (} 2 'c) .................. (2) Then, the delay time t' _d by adjusting the variable resistor 403 varies the oscillation frequency _'c, to the result which also vary It will be possible.

The aim of adjusting the delay time t _'d like is to compensate for the phase or time shift of the applied to the input terminal 1 and an input terminal 2 stereo signal. That is, the stereo signal recorded on the recording medium is a reproducing means (not shown) even if the audio signals are respectively recorded with the same phase and the same amplitude.
The phase differs from the original state due to the instability factor and the product variation. At the time of reproducing the cassette tape, 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. To prevent this situation, the second
The delay time is adjusted by the delay means 4 to compensate the audio signals of the stereo signals so that they 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 subtractor 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 the accompaniment signal is canceled, the output of the subtraction unit 501 is 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.

In the audio signal attenuator of the present invention, the detecting means is coupled to the output of the first attenuating means and the output of the adding means for attenuating the audio signal in the same manner as in the conventional example, and the input signal is detected by the detecting means. This output signal switching is performed by detecting whether the output is the monaural format and determining whether to use the output of the first attenuating means or the output of the second attenuating means as the output of the audio signal attenuating device. It is configured to be performed by means. 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. An electronic delay element called a “bucket replicate device” (hereinafter abbreviated as BBD) is used for the delay device 301 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 an adding means, which is composed of an adder 101 using an operational amplifier. Reference numeral 11 is a low-temperature 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 detection means, which is configured by applying an operational amplifier, a voltage comparator, a microcomputer, or the like. Reference numeral 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 increasing / decreasing device configured as described above will be described.

First, the input signal will be described. An audio 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 the present apparatus. 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 played back by a tape recorder, a time difference of the audio signal between the two signals occurs in the stereo signal 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) Further, the other signal of the stereo signals is supplied from the input terminal 2 to the second delay means 4 and delayed there. The delay time t ″ _d is the number of BBD stages N ″ that constitutes the delay unit 401.
And the oscillation frequency ″ _{c of the} oscillator 402 can be calculated by the following equation.

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, the delay means t ″ _d of the second delay means 4 can be changed with respect to the delay time t _d of the first delay means 3 as shown in the expressions (5), (6) and (7). Then, a time difference between two signals among the stereo signals generated in the reproducing means, the receiving device, etc. (hereinafter, abbreviated as channel time difference)
_Let t _o be the signal supplied to the input terminal 1 as a reference, and t _{o d} is adjusted so that the relation as t _o = t _d −t ″ _d ………… (8) is established. The original phase or time relationship of the stereo 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 adding means 10 is a first delay means 3 and a second delay means 4.
In response to the output of, the adder 101 performs the arithmetic processing of addition. As a result, in-phase components are added directly and components with different phases are added to the magnitude of the vector sum. When the audio signal components of the output of the first delay means 3 and the output of the second delay means 4 have the same phase and the same amplitude, the audio signal component is doubled and the accompaniment signal component has the phase and amplitude. And the vector sum (for example, the square root of the sum of squares). As a result, the audio signal component becomes larger than the accompaniment signal component, and the ratio of the audio signal component to the accompaniment signal component in the original signal can be increased. That is, it has the effect of enhancing the audio signal having the same phase and the same amplitude component. The enhancement effect of this audio signal is detected when the detection means 13 detects whether or not the input signal is a monaural signal, if such a signal in which the audio signal is amplified and a signal in which the audio signal is attenuated are used. It is convenient in that it can increase the ability. That is, if the input signal level is large to some extent whether the input signal is a stereo signal or a monaural signal, the adding means 10
This is because the signal level of the output of is large and the output of the first attenuator has a relatively large signal level if the input signal is a stereo signal, but has a small signal level close to a no signal state if the input signal is a monaural signal. .

The bass extraction unit 11 detects an accompaniment signal of a low frequency component (for example, 100 hertz or less) by the low pass filter 111. 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 performed. Is to do. That is,
The output of the adding means 10 includes the accompaniment signal although the audio signal is enhanced, and the low-pass filter 111 extracts the low frequency component of the accompaniment signal, and the mixing means 12
Is mixed with the output of the attenuator 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 detection means 13 is the output signal of the addition means 10 and the first attenuation means 9
It is detected whether the signal input to the input terminal 1 and the input terminal 2 is a stereo signal or a monaural signal based on the output signal of, and the signal whose type is detected is output to the output signal switching means 16. To do. In the present embodiment, when the output signal of the first attenuating means 9 becomes substantially no signal when the output signal of the adding means 10 is sufficiently large, the input signal is detected as a monaural signal. The details of the detecting means 13 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. Second of FIG. 3
This second damping means 15 together with an operation explanatory view of the damping means of FIG.
The operation of will be explained 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 a region of a bass range accompaniment signal having a frequency of several hundreds hertz or less, and a region where a voice signal having a frequency of several hundreds hertz to several kilohertz is mixed with a mid-range accompaniment signal. , The region of the high-pitched accompaniment signal whose frequency is several kilohertz or higher. 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 the frequency elimination characteristic having a certain slope as shown in FIG. 3b, the output signal of the bandpass filter 151 becomes as shown in FIG. 3c, and the voice signal is greatly attenuated. However, the mid-range accompaniment signal is greatly attenuated, and the low-range accompaniment signal and the high-range accompaniment signal are also partially removed, so that the sound quality is deteriorated 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 is characterized in that the deterioration of the accompaniment sound is small, 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 make up for the drawback of the first attenuating means by the second audio attenuating means which 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 13,
If the detection means 13 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 a sound quality signal attenuator, and,
If the detecting means 13 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 13 will be described in detail with reference to FIGS. 4 and 5.

FIG. 4 is a specific circuit diagram of the detection means 13, and 131 is the first
Input terminal coupled to the output of the attenuating means 9, 132 input terminal coupled to the output of the adding means 10, 133 and 134 operational amplifiers, 135 and 136 diodes, 137 and 138 resistors, and 139 and 1
Reference numeral 40 is a capacitor, 141 and 142 are voltage comparators, 143 is a microcomputer, and 144 is an output terminal coupled to the output signal switching means 14. The operational amplifier 133, the diode 135, the resistor 137, and the capacitor 139 rectify the output signal of the subtraction means 9 and convert the magnitude of the signal into the magnitude of the DC voltage. Reference DC voltage V _r1
And when the DC voltage is higher than the reference DC voltage V _r1 , the "H" signal is output to the microcomputer 143,
Conversely, when the DC voltage is lower than the reference DC voltage V _r1 , the microcomputer 143 operates so as to output a signal of "L".

Similarly, the operational amplifier 134, the diode 136, the resistor 138, the capacitor 140, and the voltage comparator 142 convert the magnitude of the output signal of the adding means 10 into the magnitude of the DC voltage, and then the voltage with the reference DC voltage V _r2. A comparison is made and an "H" or "L" signal is output to the microcomputer.

Thus, the output signal of the first attenuating means 9 is the reference voltage.
If the signal is smaller than a certain level determined by V _r1 , the output of the voltage comparator 141 is “L”, otherwise it is “H”. Also, the output signal of the adding means 10 is the reference voltage.
If the signal is smaller than a certain level determined by V _r2 , the output of the voltage comparator 142 is “L”, and if not, it is “H”. By inputting the output voltage levels of these two voltage comparators 141 and 142 to the microcomputer 143 and performing the processing in accordance with the flowchart showing the main processing of the microcomputer shown in FIG. 4, the input terminal of the audio signal attenuating apparatus of the present invention. 1 and the signal input to the input terminal 2 are detected as a stereo signal or a monaural signal. Then, the microcomputer 143 outputs a signal whose type is detected to the output terminal 144 connected to the output signal switching means 16.

Further, the operation of the microcomputer 143 will be described with reference to the flow chart of the microcomputer shown in FIG. 5 and FIGS. It is assumed that the microcomputer 143 is powered on and the reset operation and the memory erase operation necessary for the processing have been completed. First, in step 21, the memory T for counting the amount of time is set to 0. Next, in step 22, the output of the voltage comparator 142 is detected to determine whether or not the output signal of the adding means 10 is a signal larger than a certain level. If it is smaller, step 22 is repeated again, and if it is larger, step 22 is repeated. Proceed to 23.

In step 23, the output of the voltage comparator 141 is detected to determine whether or not the output signal of the first attenuating means 9 is a signal smaller than a certain level. If it is larger, it is determined that the input signal is a stereo signal. Therefore, in step 24, the memory T is set to 0, and in step 25, the signal for selecting the sound attenuation signal which is the output of the mixing means 12 is output to the output terminal 144 of the microcomputer 143 as the output signal to the output terminal 17, and step 22 Try to return to. Conversely, step 23
If it is determined that the output signal of the first attenuator 9 is smaller than a certain level, 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 sound temporarily and there is only an audio signal, it will be in the same state as a monaural signal even for one hour. Can occur in

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 143. Then, the process of outputting to 144 and returning to step 22 is performed.

Next, the operation of the entire apparatus will be described. It is assumed that the user reproduces the stereo signal by the reproducing means (not shown), supplies these signals to the input terminals 1 and 2, and listens to the signal at the output terminal 17 by the loudspeaker (not shown). 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. Thus, 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, an accompaniment component signal is almost always generated at the output of the first attenuating means 9, so that the detecting means 13 outputs the output signal of the mixing means 12 as an output terminal. A signal is sent to the output signal switching means 16 so as to be output from 17.

Further, when the signals input to the input terminals 1 and 2 are monaural signals, the output of the first attenuating means 9 is a signal of a low signal level even if a signal of a high signal level is obtained at the output of the adding means 10. Therefore, the detecting means 13 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 using a digital memory (not shown). Also, an example in which an operational amplifier is applied to the subtractor 901 adder 101 and the mixing means 12 and a low-pass filter 111 is used as the bass extraction means 11 has been described, but the same operation is digitally realized by using a microcomputer or the like. It is also possible to do so. 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, when the output signal of the adding means is a signal higher than a certain level, it is detected whether the output signal of the first attenuating means is a signal lower than a certain level, and the input signal is Whether or not it is a monaural signal is judged, but according to the recording medium to be used, the criterion for judging the signal level is not fixed to a certain level in this way but is set to a level corresponding to the average level of the input signal. It may be changed.

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

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, Second delay means capable of delaying the input signal of the other channel and changing the delay time thereof, and an output signal of the first delay means and an output signal of the second delay means are arithmetically processed to produce a voice. A first attenuator for attenuating or deleting a signal component, an adder for arithmetically processing the output signal of the first delayer and the output signal of the second delayer, and outputting an addition signal, and the adder. Bass extraction means for extracting the accompaniment signal component in the low frequency region included in the output signal of, and mixing means for mixing the output signal of the first attenuation means and the output signal of the bass extraction means,
Based on the output level of the first attenuating means and the output level of the adding means, it is detected whether or not the input signal is a monaural signal, and a detecting means for outputting the result, Either the output signal of the mixing means or the output signal of the second attenuating means, depending on the second attenuating means for attenuating or deleting the audio signal component by processing the output signal with a filter circuit. If the input signal is a stereo signal, an output signal switching means for automatically selecting and outputting the signal is provided, and as the output, a signal with a reduced sound quality mainly composed of the accompaniment signal is obtained. Of course, when the input signal is a monaural signal, a signal in which the audio signal is attenuated by a method other than the audio attenuation means for a stereo signal is automatically selected as the output signal of the device. Are those, thereby, the user is one having an excellent effect that the output signal of the recording medium to be used can practice singing without worrying that it would be a stereo signal format as would a monaural signal format.

[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 13, and FIG. 5 is a flow chart showing the main processing of the microcomputer. 3 ... First delay means, 4 ... Second delay means, 9 ... First attenuation means, 10 ... Addition means, 11 ... Bass extraction means,
12 ... mixing means, 13 ... detecting means, 15 ... second attenuating 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 which are related to each other, and one of the other channels. Second delay means capable of delaying an input signal and varying the delay time thereof, 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 a voice signal component. Included in the output signal of the first attenuating means, the adding means for calculating the output signal of the first delaying means and the output signal of the second delaying means, and outputting the added signal. Bass extraction means for extracting the accompaniment signal component in the low frequency region, mixing means for mixing the output signal of the first attenuating means and the output signal of the bass extracting means, and the output level of the first attenuating means It said input signal the output level of the serial adder means based on the detected whether the monaural signal,
The output of the mixing means is output by the detecting means for outputting the result, the second attenuating means for processing the output signal of the adding means by the filter circuit to attenuate or delete the audio signal component, and the output signal of the detecting means. An audio signal attenuating device, which automatically selects and outputs either a signal or an output signal of the second attenuating means.