JPS6350199A - Sound signal attenuator - Google Patents

Abstract

PURPOSE:To obtain signals consisting essentially of accompaniment sound by detecting whether input signals are of monaural signal form or stereoscopic signal form and outputting attenuated sound signals in the case of monaural signals. CONSTITUTION:A detecting means 14 detects whether signals inputted to input terminals 1 and 2 are stereoscopic signals or monaural signals based on the output signals of a second adding means and input signals of plural channels, and outputs a detection signal to an output signal switching means 16. Thereby, either one of output signals of a mixing means 12 or output signals of a second attenuating means 15 is selected and outputted automatically. In such a case, the second attenuating means 15 attenuates sound signal component having the frequency band of hundreds Hz to several KHz in the output signals of an adding means by using a band elimination filter 151, and thus, signals consisting essentially of accompaniment signal component are obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is applicable to playback of tapes, records, compact discs, video discs, etc., or radio.

The present invention relates to an audio signal attenuation device that processes stereo signals when receiving TV or the like and attenuates the audio signal components contained therein relative to the accompaniment signal level to facilitate singing practice.

Conventional techniques: Listening to and practicing songs is often done by reproducing various recordings or by receiving television or radio. These recording media often record a mixture of the singing voice of a professional singer and accompaniment.

Similarly, radio and television broadcasts also include singing voices and accompaniment. When practicing singing through these media, it is easier to practice at first when the singer's voice is included since you are not used to it, but as you get used to it, you will want to sing with just the accompaniment. In this case, the professional singer's singing voice may actually interfere with practice.

As one way to achieve this, tapes commonly called "karaoke" are also available on the market. These include only accompaniment, and recordings of a professional singer's singing voice and accompaniment separately. However, it can take a long time for these new songs to be released on the market, and it can be difficult to match them to your tastes.

In order to meet the above needs, there have been conventional sound attenuation devices such as Haggi. The explanation will be given below with reference to all the drawings. FIG. 2 is an example of a conventional audio signal attenuation device.

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 means, 8 is the output terminal It is. The first delay means 3 includes a delay device 301 using, for example, an electronic delay element "packet pregate device" (hereinafter abbreviated as BBD), and an oscillator 302 that generates a clock signal. The second delay means 4 includes a delay device 401, an oscillator 4o2, and a variable resistor 403 for adjusting the oscillation frequency. The delay device 4o1 uses the same type of BBDi as the delay device 301 described above. The subtraction unit 5 is composed of a subtracter 601 using an arithmetic amplification device. The bass detection section 6 includes an adder 6o1 using an operational amplifier and a low-pass filter 602.
It consists of

The operation of the conventional sound attenuation device configured as described above will be explained. The signal obtained when playing back a recording medium, etc. is a stereo signal, and the signal contains a mixture of voices such as singing and accompaniment, 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 certain period of time. The delay time t (1 is the number N of BBD stages constituting the delay device 301 and the oscillation frequency fa of the oscillator 302
The directness can be calculated using the following formula.

ta = N/(2f, )...
(1) The signal at the other input terminal 2 is delayed by the second delay means 4, and its value t can be calculated from the number of stages N7 of the delay device 401 (BBI) and the oscillation frequency f0' of the oscillator 402.

ta' = N' / (2fc')
...), and the delay time t(1' is the oscillation frequency, l-0/, which changes by adjusting the variable resistor 403,
As a result, this too can be changed.

The purpose of adjusting the delay time t(1' in this manner) is to fully compensate for the phase or time shift of the stereo signals applied to the input terminals 1 and 2.

In other words, even if the audio signals are recorded with the same phase and the same amplitude, the stereo signals recorded on the recording medium may differ in phase from the original state due to unstable factors in the reproduction means (not shown) or product variations. ing. Particularly when playing back a cassette tape, there is a large phase shift in the audio signal due to unstable factors in the running system and variations in the halves in which the cassette tape is stored.

The higher the recording frequency is, the larger the phase shift becomes. For this reason, it becomes difficult to attenuate the audio signal even if arithmetic processing, which will be described later, is performed. To prevent this condition,
The second delay means 4 adjusts the delay time to compensate so that the audio signals of the stereo signals are in the same phase.

The output of the first delay means 3 and the output of the second delay means 4 are subtracted by a subtractor 6. Now, assuming that the audio signals in the output of the first delay means 3 and the output of the second delay means 4 are in phase and have approximately the same level f'4, the subtracter 601
However, since the accompaniment signal is a stereo signal and has a different phase and amplitude, it is generated as the output of the subtracter 501. Note that signals from musical instruments with low frequency components in the accompaniment signal, such as drums and bass, often have the same magnitude and phase even if they are stereo signals (the lower the frequency, the less directivity). (It may not be possible to separate and record as stereo when recording.) Therefore, subtractor 5
The output of 01 has fewer low frequency components of the accompaniment.

There is a bass detection section 6a that compensates for this low frequency component.
An adder 601 performs an addition operation on the output of the first delay means 3 and the output of the second delay means 4, and a low-pass filter 602 extracts an accompaniment sound having a frequency lower than the audio frequency band.

Next, the mixing means 7 mixes the output of the subtraction section 5 and the output of the bass detection section 6, and outputs the mixture to the output terminal 8. Therefore, the user can listen to only the accompaniment sound by adjusting the variable resistor 403 and setting the sound to the lowest level while listening to the sound through a public address system (not shown) connected to the output terminal 8. It is.

Problems to be Solved by the Invention By the way, there are many types of recording media that output a signal format called a monaural signal in addition to a stereo signal. A monaural signal has two or more output signal lines like a stereo signal, but the signals output to these multiple output signal lines, including the audio signal and accompaniment signal, are the same, so it is not like a stereo signal. The signals output to each output signal line are related to each other, but each is independent; that is, the audio signal is common to each output signal line, but the accompaniment signal is different. There is.

Normally, such a monaural signal has almost the same signal level and almost the same phase on each output signal line, so in the conventional audio signal attenuation device, the input signal is converted into an audio signal by the subtracter 501. Since both the accompaniment signal and the accompaniment signal are canceled, the output of the subtraction section 501 is always almost no signal, and only the low frequency component of the input signal extracted by the bass detection section 6 is outputted to the output terminal 8 via the mixing means 7. The problem is that the user can only hear the low-frequency components, making it extremely unusable for singing practice.

In view of the above problems, the present invention detects whether an input signal is a monaural signal format or a stereo signal format, and when the input signal is a stereo signal format, the audio signal is attenuated using the method mentioned in the conventional example. However, when a monaural signal is output, a signal is output in which the audio signal is attenuated using a method different from conventional methods. The present invention provides an audio signal attenuation device obtained by the present invention.

Means for Solving the Problems In order to solve the above problems, the audio signal attenuation device of the present invention includes a detection means for detecting when the input signal is in monaural signal format, and a detecting means for detecting that when the input signal is in monaural signal format, and a second attenuation means that uses a method different from the conventional example in order to attenuate the signal and extract a signal mainly consisting of an accompaniment signal; and an output of the second attenuation means when the signal is monaural in response to the output of the detection means; An output signal switching means for outputting a signal is provided.

Operation In the audio signal attenuation device of the present invention, the detection means is coupled to the input signals of a plurality of channels and the output of the second addition means for adding up all the input signals, and the detection means determines whether the input signal is in monaural format or not. The audio signal attenuation device detects the output signal, determines whether to use the output of the first attenuation means or the output of the second attenuation means as the output of the audio signal attenuation device, and performs this output signal switching by the output signal switching means. ing. Therefore, if the input signal is a stereo signal, the output signal is a signal obtained by subtracting all the output signals of the two delay means by the first attenuation means, and the audio signal is attenuated. However, if the input signal is a monaural signal, the output signal is the attenuated signal. can realize a new function of being automatically switched to the output signal of the second attenuation means.

Embodiment Hereinafter, an audio signal attenuation device according to an embodiment of the present invention will be explained 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 designates an input terminal to which accompaniment and voice are synthesized as well as mutually related signals such as stereo signals, and 2 designates an input terminal to which the other signal is supplied. 3 is a first delay means, which is composed of a delay device 301 and an oscillator 302 that generates a clock thereof. For example, the delay device 301 includes a “1 bucket bricate device” (hereinafter referred to as B
An electronic delay element called BD (abbreviated as BD) is used. 4
is a second delay means, which is composed of a delay device 401, an oscillator 402 that generates a clock, and a variable resistor 403 that changes the frequency of the oscillator 402. The delay device 401 is the same as the delay device 301 (BBD is used.

9 is a first attenuation means, which is composed of a subtracter 901 using an operational amplifier. 1o is a first addition means, which is composed of an adder 101 using an operational amplifier. Reference numeral 11 denotes a bass extracting means, which is composed of a bass filter 111. 12
is a mixing means and is constructed by applying an operational amplifier. Reference numeral 13 denotes a second adding means, which adds the input signals input to input terminals 1 and 2, and is composed of an adder 130 used as an operational amplifier. Reference numeral 14 denotes a detection means, which is constructed by applying all the components such as an operational amplifier, an AD converter, and a microcomputer. Reference numeral 15 denotes a second attenuation means, which is composed of a band elimination filter 161 using an arithmetic amplification device. It is a 16TFI output signal switching means, and consists of analog electronic switches and relays that apply FIT all around. Reference numeral 17 denotes an output terminal for outputting an attenuated audio signal to a device (not shown) such as a public address system.

The operation of the audio signal attenuation device configured as above will be explained.

First, the input signal will be described. A signal in which an audio signal such as a singing voice of a professional singer and an accompaniment signal of a musical instrument are synthesized and are mutually related, for example, a stereo signal, is input to the apparatus. Recently, signals of a plurality of channels such as 4 channels are sometimes used as one of three-dimensional sound reproduction means, but these are also included in the stereo signal.

By the way, in general, in the stereo system, audio signals are often formed between two signals with the same phase and the same amplitude. This is because if the phase or vibration of the audio signal differs or changes between the two signals, when playing back in stereo, the sound image of the audio will not be localized in the center, but will be reproduced in a position that seems to have moved to one of the sides. , the position may change unstablely, causing a problem sound. Furthermore, when a stereo signal is reproduced monaurally, the audio signal may cancel out and become smaller than its original size. On the other hand, accompaniment signals are often formed so that separate musical instrument signals are inserted between two stereo signals in order to create a sense of realism.

When playing this stereo signal from all recording media or receiving broadcast radio waves, a time difference that differs from the original state may occur between the two reproduced stereo signals due to differences in equipment performance, variations, unstable factors, etc. The vibration level may also change as a phase difference occurs. For example, when a cassette tape is played back on a full tape recorder, the time difference between the two audio signals will occur at most 200 to 300 microseconds.If there is such a time difference, the audio signal will be attenuated from the stereo signal. things become difficult. In order to compensate for this, the first delay means 3 and the second delay means 4 perform time adjustment, that is, phase sterilization. Then, the audio signal level is attenuated by the subsequent arithmetic processing.

Next, detailed operation explanation of each part will be given. First delay means 3
One of the stereo signals supplied to the delay device 3
Delayed by 01. The delay time t(1 is calculated by the following equation using the oscillation frequency fa of the oscillator 02, which is the number of N1 stages of the BBD constituting the delay device 301i.

ta = N/(2f0)...
(3) Also, 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 ta I is determined by the number of stages N' of BBD constituting the delay device 4C)1 and the firing frequency f of the oscillator 402.
cI and can be calculated using the following formula.

td ″” N' / (2f,?)
,,, +·H(4) The relative relationship between the oscillation frequency and the delay time is as follows.

However, it is assumed to be N-N'.

That is, as shown in equations (5), (6), and (7), the delay time td' of the second delay means 4 can be changed with respect to the delay time td of the first delay means 3. and,
The time difference (hereinafter abbreviated as channel time difference) between two stereo signals generated in the reproduction means, receiving equipment, etc. is calculated by
and t(1=t(1-t(1"...
...If ta' is adjusted so that the relationship as shown in (8) is established, the original phase or time relationship of the Stereth signal can be restored.

In other words, it refers to the performance of devices such as means for reproducing recording media (e.g. tapes and discs) and means for receiving broadcast waves (e.g. radios and televisions).

Even if there is a steady phase difference or time difference between the plurality of channel outputs (stereo outputs) due to unstable factors, 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
The output means that the same phase or time relationship as when recording on the recording medium is reproduced, and the audio signal components are in the same phase.

The first attenuation means 9 receives outputs from the first delay means 3 and the second delay means 4, respectively, and performs arithmetic processing of subtraction between them. For example, by performing subtraction in the subtracter 901, signals of in-phase components are outputted, and components with different phases are outputted.

Therefore, audio signal components having the same phase are attenuated or eliminated to zero by the subtracter 901, and accompaniment signal components having different phases are generated as the output of the subtracter 901. In other words, it achieves the effect of attenuating the audio signal.

The first addition means 1o receives the outputs of the first delay means 3 and the second delay means 4 and performs the calculation process of addition to the adder 1o1.
I'll do it at

The bass extraction means 11 uses a low-pass filter 111 to extract accompaniment signals of low frequency components (for example, 100 hertz or less). The purpose of this is that when the attenuation means 9 performs a subtraction operation, audio signal components of the same phase are attenuated, but accompaniment components of low frequency components below 100 Hz are also easily attenuated due to a small phase difference. The goal is to let them do everything. That is, a low-frequency component of the accompaniment signal output from the first addition means 1o is extracted by a low-pass filter 111, and mixed with the output of the attenuation means 9 by a mixing means 12. As a result, the mixing means 12 outputs an accompaniment signal in which the audio signal component is attenuated or deleted. The second adding means 13 is for adding input signals of a plurality of channels, and if the input signals have the same amplitude and the same phase, it outputs a signal with twice the amplitude 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 the plurality of channels. Then, the signal that detects the type is output to the output signal switching means 16. In this embodiment, when the magnitude of the output signal of the second adding means 13 becomes twice the signal level of the input signals of a plurality of channels, it is assumed that the input signal is detected to be a monaural signal. The details of this detection means 14 will be described later.

The second attenuation means 16 uses a band elimination filter 161 to attenuate the audio signal component having a frequency band from several hundred hertz to several kilohertz of the output signal of the addition means 1o, in order to obtain a signal mainly consisting of the accompaniment signal component. It is something to do.

This second damping means along with the operation explanatory diagram of the second damping means in FIG.
The operation of the damping means 15 will be explained in more detail.

The input signal to the second attenuation means 15, that is, the input signal to the band-rejection filter 161 will be described as having a frequency spectrum as shown in FIG. 3B.

As shown in FIG. 3, the input signal of the band-rejection filter 151 is divided into a region of a low-frequency accompaniment signal with a frequency of several hundred hertz or less, an audio signal with a frequency of several hundred hertz to several kilohertz, and a mixture of a medium-frequency accompaniment signal. It is broadly classified into the region and the region of high-frequency accompaniment signals whose frequency is several kilohertz or more. It is only necessary to remove the audio signal component from such an input signal.

However, since the actual frequency custom-made band-rejection filter has a frequency removal characteristic with a certain slope as shown in Figure 3, the output signal of the band-rejection filter 151 will be as shown in Figure 3C, and the audio signal will be large. However, the mid-range accompaniment signal is also greatly attenuated, and some of the low-range accompaniment signals and high-range accompaniment signals are also removed, resulting in a certain degree of deterioration in sound quality.

Unlike this method using a band-rejection filter, the method that subtracts the two delay means used in the first attenuation means has the major advantage that there is little deterioration of the accompaniment sound, but when the input signal is a monaural signal, has the disadvantage that the accompaniment signal is also removed. It is an object of the present invention to compensate for the drawbacks of the first attenuation means with a second sound attenuation means that can be used even when the input signal is a monaural signal, although it causes a certain degree of sound quality deterioration.

The output signal switching means 16 receives the output signal of the detection means 14, and if the detection means 14 determines that the input signal is a stereo signal, the output signal switching means 16 switches the output signal to an output terminal 17 as an audio signal attenuation device.
If the detection means 14 determines that the input signal is a monaural signal, the second attenuation means 1 is output to the output terminal 17.
5 output signals are transmitted.

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

FIG. 4 is a concrete circuit diagram of the detection means 14, and 13
Reference numeral 1 denotes an input terminal for inputting an L channel input signal, which is one signal among the input signals of multiple channels (here, the stereo second channel signal), and 132, an R channel input signal, which is the other signal of the input signals of the multiple channels. 133 is an input terminal coupled to the output of the second adding means 13; 134 to 138 are arithmetic multipliers 1; 137
-139 are diodes, 140-142 are resistors, 14
3 to 145 are capacitors, 146 to 148 are AD converters, 149 is a microcomputer, and 160 is an output terminal coupled to the output signal switching means 14.

Operational amplifier 134. Diode 137. resistor 14o,
The capacitor 143 rectifies the L channel input signal and converts the signal magnitude to the DC voltage magnitude.
The D converter 146 converts a DC voltage representing the signal magnitude into a digital signal, and outputs the level of the L channel input signal as a digital signal to the microcomputer 149. Similarly, operational amplifier 136. Diode 138. Resistor 141. A digital signal corresponding to the level of the R channel input signal is obtained from the output of the λD converter 147 by the capacitor 144 and the AD converter 147, and is output to the microcomputer 149. Also, operational amplifier 136. Diode 139. Resistor 142. The capacitor 146° AD converter 148 provides the output of the AD converter 148 with the level of the output signal of the second adding means 13 as a digital signal, and outputs it to the microcomputer 149.

The microcomputer 149 has AD converters 146 to 14
By performing arithmetic processing on the digital signals that are the output signals of 8, it is determined whether or not a plurality of input signals are monaural signals, and the result is output to the output terminal 150.

The operation of the microcomputer 150 will be explained below with reference to the flowchart of the microcomputer shown in FIG.

It is assumed that the microcomputer 149 is powered on and that the reset operation and memory erasing operation necessary for processing have been completed. First, in step 21, the memory T for counting time quantities 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 almost the same, that is, the input signals of multiple channels are It is determined whether the signal levels are approximately the same magnitude, and if the magnitudes are significantly different, step 22 is repeated again; if they are approximately the same, the process proceeds to step 23.

In step 23, the output signal of the MU D converter 148 is compared with the output signal of the MU D converter 146 or the output signal of the MU D converter 147, and the output signal of the second adding means 13 is determined as the input signal of the plural channels. It is determined whether the signal level is approximately twice that of Tf. If the signal level is approximately twice that of
:, o, and in step 25 a signal for selecting the audio attenuation signal output from the mixing means 12 as the output signal to the output terminal 17 is output to the output terminal 150 of the microcomputer 149, and the process returns to step 22. . Conversely, if it is determined in step 23 that the output signal of the second adding means 13 has a signal level approximately twice that of the input signals of the plurality of channels, the value in the memory T is added by 1 in step 26, and the value in the memory T is added in step 27. Then, it is determined whether the value of this memory T exceeds a certain constant value. The determination in step 27 is to prevent the output signal to be switched to the output terminal 17 immediately after detecting that the input signal is a monaural signal even if the input signal is a monaural signal. In other words, if there is no determination in step 27, the input signal may be determined to be a monaural signal at one point in time, and then determined to be a stereo signal at the next point in time, even though the input signal is a stereo signal depending on the program of the input signal. This is because the signal output to the output terminal 17 may be switched over and over again during the same song. The reason for this is that even if the input signal is a stereo signal, if the accompaniment sound temporarily disappears and only the audio signal remains, the state becomes the same as a monaural signal, even if only temporarily.Such a situation is normal. can occur.

Now, the judgment in step 27 is made by comparing the value in the memory 'l'' with a constant to determine whether a sufficient amount of time, for example 5 seconds, has elapsed since the input signal became a monaural signal. is set to a value that can be considered as a sufficient time after the signal becomes a monaural signal.If it is determined in step 27 that sufficient time has elapsed since the signal becomes a monaural signal, the process proceeds to step 28, and the output to the output terminal 17 is performed. A signal for selecting the output signal of the second attenuation means is outputted to the output terminal 150 of the microcomputer 149, and the process returns to step 22.

Next, the operation of the entire device will be explained. In FIG. 1, the user reproduces stereo signals with a reproduction means (not shown), supplies those signals to input terminals 1 and 2, and listens to the signal at output terminal 17 with a public address system (not shown). shall be. It is assumed that the audio signal components of the stereo signal are recorded on a recording medium (not shown) with the same phase and amplitude between the respective channels. In this state,
The variable resistor 403 is connected so that the audio signal component is minimized.
iAdjust. That is, even if the phases of the audio signal components of the stereo signals applied to the input terminals 1 and 2 differ due to the performance or variation of the reproduction means, the delay action of the first delay means 3 and the delay action of the second delay means 4 are different. Due to the delay effect, the audio signal components at the output of the first delay means 3 and the output of the second delay means 4 can be in phase.

The first attenuation means 9 subtracts (or makes a difference) between the output of the first delay means 3 and the output of the second delay means 4 using a subtracter 901, and the output thereof is an audio signal component having the same phase relationship. is greatly attenuated, resulting in accompaniment signal components with different phase relationships. In other words, the effect of attenuating the audio signal is realized.

Note that in the first attenuation means 9, low frequency accompaniment signal components may be attenuated at the same time due to a small phase difference.
The accompaniment signal component extracted by the bass extraction means 11 and the output of the first attenuation means 9 are supplied to the mixing means to bring the accompaniment signal closer to its original state.

When the signals input to input terminals 1 and 2 are stereo signals, the two input signals usually have different levels and phases, and the two input signals have different levels, and the output signal of the second adding means is different. Since the signal level is not approximately twice that of the two input signals, the detection means 14 detects that the mixing means 1
A signal is sent to the output signal switching means 16 so that the second output signal is output from the output terminal 17.

Furthermore, when the signals input to input terminals 1 and 2 are monaural signals, the two input signal levels are approximately the same, and the output signal of the second adding means 13 is approximately twice as large as the two input signals. The detection means 14
operates to send a signal to the output signal switching means 16 so that the output signal of the second attenuation means 1S is output from the output terminal 17.

In the embodiment shown in FIG. 1, BBDi is used for the delay devices 301 and 401, but the same effect can be achieved using a digital memory (not shown).

Also, subtractor 9o1. Although we have explained vl in which an operational amplifier is applied to the adder 101 and the mixing means 12, and a low-pass filter 1111 is used as the bass extracting means 11,
Is it the same effect using a microcomputer, etc.? It is also possible to implement it digitally.Although this embodiment shows an example in which a microcomputer 2 is used as the detection means, it is also possible to implement analog circuits and general-purpose digital circuits without using such a microcomputer. It is also possible to achieve the same effect by combining them.

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

In addition, in this embodiment, 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 processing operation of the microcomputer as the detection means is changed to a monaural signal even if temporarily. It determines that it is a signal and switches the output of the audio signal attenuator. To avoid this inconvenience, you can decide whether the input signal is a stereo signal or a monaural signal within a certain time at the beginning of the song, and do not change this decision until the entire song is played. good.

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

Further, in this embodiment, three circuits including AD converters are provided to detect the signal levels of the input signal input from the input terminal and the output signal of the second addition means, but only one circuit is provided. Three signal levels may be detected by time-sharing processing as described above. Effects of the Invention As described above, the present invention is capable of detecting input signals of multiple channels in which accompaniment music signals and audio signals are mixed and are mutually related. a first delay means that delays the input signal of one channel; a second delay means that delays the input signal of the other channel and can vary the delay time; and an output signal of the first delay means. and a first attenuation means for processing the output signal of the second delay means to attenuate or delete the audio signal component; and an output signal of the first delay means and an output signal of the second delay means. a first addition means for performing arithmetic processing and outputting an added signal; a bass extraction means for extracting an accompaniment signal component in a low frequency region included in the output signal of the first addition means; and a first attenuation means. mixing means for completely mixing the output signal with the output signal of the bass extracting means; a second addition means for adding up the input signals of the plurality of channels; detecting means for detecting whether the input signal is a monaural signal based on the level of the output signal and outputting the result; and a filter circuit processing the output signal of the first adding means. A second attenuation means for attenuating or deleting an audio signal component, and an output signal of the mixing means or the output signal of the second attenuation means is automatically selected and output based on the output/signal of the detection means. Equipped with an output signal switching means, when the input signal is a stereo signal, the audio signal is attenuated and the accompaniment signal is the main component, resulting in a signal with little deterioration in sound quality. If it is a signal, a signal whose audio signal has been attenuated by a method other than the audio attenuation method used for stereo signals is automatically selected as the output signal of the device, and this allows the user to adjust the output of the recording medium used. This has the excellent effect of allowing one to practice singing without worrying about whether the signal is in a stereo signal format or a monaural signal format.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the audio signal attenuation device of the present invention, FIG. 2 is a block diagram of a conventional audio signal attenuation device, FIG. 3 is an explanatory diagram of the operation of the second attenuation means, and FIG. The figure is a concrete circuit diagram of the detection means, and FIG. 5 is a flowchart showing the main processing of the microcomputer. 3...First delay means, 4...Second delay means, 9...First attenuation means, 1o...
...First addition means, 11...Bass extraction means, 12...Mixing means, 13...
Second addition means, 14...Detection means, 15...
. . . second attenuation means, 16 . . . output signal switching means. Name of agent: Patent attorney Toshio Nakao Haga 1st person
1!21 Figure 2 Figure 3 (b) Output signal of Yoiken & Fi) K Rino) (0) Area Jusku Skaruta output signal Figure 4

Claims (1)

[Claims] A first delay means for delaying an input signal of one channel among a plurality of mutually related input signals in which accompaniment music signals and audio signals are mixed; and a first delay means for delaying an input signal of the other channel; a second delay means that can vary the delay time; and a first attenuation means that performs arithmetic processing on the output signal of the first delay means and the output signal of the second delay means to attenuate or delete an audio signal component. , a first addition means for processing the output signal of the first delay means and the output signal of the second delay means and outputting a sum signal; bass extracting means for extracting an accompaniment signal component in the frequency domain; mixing means for mixing the output signal of the first attenuating means and the output signal of the bass extracting means; and a second mixing means for adding the input signals of the plurality of channels. adding means, detecting whether or not the input signal is a monaural signal based on the level of the input signal of the plurality of channels and the level of the output signal of the second adding means, and outputting the result. detection means for
A second attenuation means processes the output signal of the first addition means in a filter circuit to attenuate or delete the audio signal component, and the output signal of the detection means is used to reduce the output signal of the mixing means or the second An audio signal attenuation device comprising output signal switching means for automatically selecting and outputting one of the output signals of the attenuation means.