JPS6341152B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an accompaniment music playback device, and particularly to an envelope detection means, an envelope difference detection means,
The present invention relates to an accompaniment music reproducing device comprising absolute value detection means, integration means, level detection means and display means.

So-called karaoke has now become a product category, but when amateurs actually sing, it is difficult to judge when to start singing, so they sometimes start singing in the introduction before the singing section, or they start singing after the introduction before the singing section. I often make mistakes, such as having to hurry up and sing along to the accompaniment.

Normally, when a band or accompanist is present, it is possible to signal the singer when to start singing, but similarly, in karaoke, it is extremely necessary for amateurs to signal when to start singing. As a method of signaling when to start singing at karaoke, there is a monaural recording section that records the same sound on multiple tracks of a singing accompaniment music tape, that is, only one of the left and right microphone signals, and multiple sounds on the multiple tracks.
That is, there is a technique in which a stereo recording section is provided that records left and right microphone signals, respectively, and the singing start time is indicated by a change in the localization of the sound image of the two recording sections, that is, a difference in the spread of accompaniment music. In other words, the introductory part before the singing section is composed of a monaural recording section alone, or a monaural recording section and a stereo recording section are provided alternately, and the accompaniment section after the singing section is composed of a stereo recording section alone. be.

When such a singing accompaniment music tape is played back in stereo, the accompaniment music will be heard from the center of the left and right speakers in the monaural recording section, but the accompaniment music will be heard from the center of the left and right speakers in the stereo recording section. I hear music.

This difference in the spread of the accompaniment music allows the singer to know when to start singing. In this technology, the time to start singing is notified by hearing, but since there is an accompanist, in order to start singing in response to a signal from the accompanist, it is necessary not only to hear but also visually. It is necessary to know when singing starts.

To satisfy this need, there is provided a high frequency removal means, a phase comparison means for comparing the phases of the left and right channel signals, and a phase difference level that generates an output when the phase difference between the left and right channel signals exceeds a predetermined value. A detecting means and a singing start instructing means for instructing the singer when to start singing are provided, the phases of the left and right channel signals from which the high frequency components have been removed by the high frequency removing means are compared by the phase comparing means; An accompaniment that generates an output voltage in the phase difference level detection means when the phase comparison output exceeds a predetermined value, and uses the generated voltage to turn on the singing start instructing means to instruct the singer when to start singing. There is a music playback device.

This is because in a monaural recording section, only one of the left and right microphone signals is recorded on multiple tracks, and the signal is the same and there is no phase difference, so the output of the phase comparison means is zero, but in the stereo recording section, the reflected sound This method takes advantage of the fact that since there is always a phase difference between the left and right channel signals, an output is generated in the phase comparison means.

Therefore, when playing back a monaural recording section, if there is a level difference or phase shift between the left and right channel signals, or if a predetermined value is exceeded due to noise, an output is generated to the phase comparison means, and the monaural recording is completed. There is a problem in that there is a risk of a malfunction that indicates that it is a stereo recording section even though it is a stereo recording section.

This invention was made by focusing on the problems of the prior art, and includes an envelope detection means,
It is an object of the present invention to solve the above problems by providing envelope difference detection means, absolute value detection means, integration means, level detection means, and display means.

The present invention will be explained below based on the drawings. FIG. 1 is a diagram showing an embodiment of the present invention.

1 is an envelope detection means, which has multiple channels.
This records the envelope of the output signals of CH ₁ and CH ₂ . The envelope detection means 1 is composed of a rectifier and a filter. Alternatively, the linear detection means may be composed of an operational amplifier, a rectifier, and a resistor. This linear detection makes it possible to accurately extract the envelope of the channel output signal even when the signal is small, and this signal makes it possible to improve the accuracy of the difference signal between both channels.

Reference numeral 2 denotes envelope difference detection means, which detects the difference between the output signals _E1 of the plurality of envelope detection means 1.

When the envelope detection means 1 performs in-phase detection in the channel CH ₁ and the channel CH ₂ , a differential amplifier or the like is used as the envelope difference detection means 2.

When performing anti-phase detection with envelope detection means 1 on channel CH ₁ and channel CH ₂ , add the output signals E ₁ of both channels,
Obtain the difference signal _E2 .

The monaural recording section M, which records only one of the left and right microphone signals on multiple tracks, is a channel.
When added to CH ₁ and CH ₂ , the output of the envelope difference detection means 2 becomes zero as shown in FIG. channel
When applied to CH ₁ and CH ₂ , the envelope difference detection means 2 shows a positive or negative output as shown in FIG. 2b. Depending on the presence or absence of this difference signal _E2 , it is determined whether the recording section is a monaural recording section M or a stereo recording section S.

Reference numeral 3 denotes an absolute value detection means for detecting the absolute value of the difference signal E2 of the envelope difference detection means ₂ .

The difference signal E2 of the envelope difference detection means ₂ is the second
As shown in Figure b, the difference signal E 2 is taken out as a positive or negative signal, but since it is not possible to clearly determine whether it is stereo, monaural, or no signal input with only one side of the signal, the absolute value detection means 3 extracts the difference signal E ₂ . The absolute value is extracted to more clearly determine the presence or absence of the difference signal _E2 . A full-wave rectifier circuit is used as the absolute value detection means 3.

4 is an integrating means, which receives the output signal of the absolute value detecting means 3;
This makes the portion of E ₃ that changes over a minute period of time insensitive. During playback of the monaural recording section M, if there is a slight phase difference in the playback device, a phase difference will occur between the signals of channel CH ₁ and channel CH ₂ as shown in FIG. Generates a difference signal _E2 within a minute time. Also, when noise temporarily occurs in one side of the recording/reproducing transmission system, a difference signal _E2 within a minute time is generated similarly as shown in FIG. 3b. Although the output signal E ₃ of the absolute value detection means ₃ based on these difference signals E 2 is small, the integration means 4 is insensitive to the changes within these minute times and detects slight phase differences and This prevents the stereo recording section S from being mistakenly detected due to noise. A low-pass filter is used as the integrating means 4.

5 is a level detection means, which detects the output signal of the integrating means 4.
It is insensitive to minute levels of _E4 .

When there is a level difference between channel CH ₁ and channel CH ₂ in the recording/playback system, the monaural recording section M
The envelope difference detection means ₂ generates a difference signal E2 as the envelope difference during reproduction. This difference signal E ₂
The output signal E ₃ of the absolute value detection means ₃ based on
occurs. The output signal _E4 at this time is minute compared to when the stereo recording section S is played back, but the level detection means 5 is insensitive to this minute level, and when the monaural recording section M is played back, the output signal E4 is erroneously detected in the stereo recording section due to the level difference. This prevents it from being detected as S. Therefore, during playback of the stereo recording section S, the level detection means 5 always generates an output signal _E5 of a certain level or higher. A Schmitt circuit is used as the level detection means 5.

Reference numeral 6 denotes a display means that lights up to indicate when the stereo recording section S is playing back based on the output signal E5 of a certain level or higher from the level detection means ₅ . By the lighting display on the display means 6, the singer can know when the stereo recording section S will start playing, that is, when singing will start.

If there is a light display on the display means 6, and there is a time lag between when the singer sees it and starts singing, and there is a delay in the song, the time required for the display and the time from the singer's visual stimulus to the start of singing, that is, the stimulus. Considering the action time, as shown in Figure 4, the stereo recording section starts from the end of the introductory part i before the singing part, or in other words, from a certain time T (about 0.5 seconds) before the beginning of the accompaniment part s after the singing part. It is preferable to record a monaural recording section M and a stereo recording section S so as to form a recording section S.

The display means 6 may be provided in a place where the singer can clearly see the singer, for example, in front of the device or on a microphone or a microphone stand.

As shown in FIG. 5, a control means _SW1 is provided in the microphone circuit to control the operation/non-operation of the microphone Mic by the output signal _E5 of the level detection means 5, and when the monaural recording section M is played back, the microphone Mic
If you disable the microphone Mic while playing back the stereo recording section S, even if you accidentally start singing during the playback of the monaural recording section M and before the display means 6 does not display, no sound will come out from the speaker s.
The singer can recognize that he or she has made a mistake in starting the song and can sing again after the display appears again. It is also possible to prevent unnecessary howling when playing back the monaural recording section M.

SW ₂ in FIG. 5 is a forced interrupt switch that forcibly operates the microphone Mic at the singer's will so that the singer can speak freely during playback of the monaural recording section M.

As explained above, the present invention detects the level difference and phase shift between left and right channel signals by comprising envelope detection means, envelope difference detection means, absolute value detection means, integration means, level detection means, and display means. Alternatively, it is possible to prevent an erroneous operation in which a monaural recording section is determined to be a stereo recording section due to the inclusion of noise.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 a shows the output signal of the envelope detection means and the envelope difference detection means when the monaural recording section and the stereo recording section are added to a plurality of channels. FIG. 3A shows the envelope difference detection means when there is a phase difference in the playback device when playing back a monaural recording section, and FIG. 3 shows an envelope difference detection means when noise is mixed into one side of the recording/playback system when playing back a monaural recording section. Figure 4 is a diagram showing the timing of the singing start and the formation of the monaural recording section and the stereo recording section, and Figure 5 is a diagram showing the waveform of the output signal of the level detection means.・
It is a figure which shows the control means which controls non-operation. DESCRIPTION OF SYMBOLS 1... Envelope detection means, 2... Envelope difference detection means, 3... Absolute value detection means, 4... Integration means, 5... Level detection means, 6... Display means.

Claims (1)

[Claims] 1. Play back a singing accompaniment music tape that is composed of a monaural recording section in which only one of the left and right microphone signals is recorded on multiple tracks and a stereo recording section in which each of the left and right microphone signals is recorded on the plurality of tracks. In an accompaniment music playback device,
a plurality of envelope detection means for detecting envelopes of output signals of a plurality of channels; envelope difference detection means for detecting a difference between output signals of the envelope detection means; and an absolute value for detecting the absolute value of the difference signal of the envelope difference detection means. a value detecting means; an integrating means for making insensible a portion of the output signal of the absolute value detecting means within minute time when the monaural recording section is played back; and an output signal of the integrating means when the monaural recording section is playing back. 1. An accompaniment music reproducing apparatus comprising: a level detecting means for making minute levels of the noise insensitive; and a display means for displaying a reproducing operation of a stereo recording section based on an output signal of the level detecting means.