Patent Grant
8036389
This application claims priority under 35 U.S.C. 119(a) from Korean Patent Application No. 10-2005-0089504, filed on Sep. 26, 2005, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
1. Field of the Invention
The present general inventive concept relates to a karaoke system, and more particularly, to a vocal canceling apparatus and method of canceling a vocal component in a karaoke system.
2. Description of the Related Art
Generally, a karaoke system uses as an accompaniment, in which an audio signal is output from an audio device, such as a cassette player, a compact disc player or a tuner, and in which only a human vocal component is canceled. Most vocal components exist in a frequency band of 200 Hz to 4 kHz in the audio signal. A vocal signal is a single signal, that is, a mono signal, in an audio system. A music signal including sound of musical instruments is separated into a left channel and a right channel. Accordingly, except for the mono signal, waveforms of the audio signal input to a left channel terminal and the audio signal input to a right channel terminal are different to each other. Therefore, if the audio signal input to the left channel is subtracted from the audio signal input to the right channel, the audio signal in which the vocal signal is canceled can be generated. Generally, in a method of canceling a vocal component in a stereo music file, a difference between the left and right channels is obtained to cancel the vocal component since the vocal component, that is, voice of a singer, is located at a center channel of the audio signal.
U.S. Pat. No. 6,690,799 B1 discloses a ‘stereo signal processing apparatus’ relating to a vocal canceling circuit.
Accordingly, the vocal canceling circuit of
The present general inventive concept provides a vocal canceling apparatus and method capable of easily implementing a karaoke mode using an ordinary stereo file by attenuating a vocal component with using a cross mix structure in a stereo channel audio signal.
The present general inventive concept also provides a karaoke system capable of easily implementing a karaoke mode using an ordinary stereo file by attenuating a vocal component with using a cross mix structure in a stereo channel audio signal.
Additional aspects and advantages of the present general inventive concept will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the general inventive concept.
The foregoing and/or other aspects of the present general inventive concept may be achieved by providing an apparatus to cancel a vocal component, the apparatus comprising a first vocal canceling unit to delay each of left and right channel input signals for a predetermined time and to feed-forward cross mix the delayed left and right channel input signals with the right and left channel input signals, a sound stage widening unit to delay each of the left and right channel signals output from the first vocal canceling unit for a predetermined time and to feedback cross mix the delayed left and right channel signals with the right and left channel signals to generate second left and right channel signals, and a second vocal canceling unit to low-pass filter the second left and right channel signals output from the sound stage widening unit and to cancel a vocal component by mixing the low-pass filtered second left and right channel signals having low frequency components, and a high frequency component of a difference between the second left and right channels to generate final left and right channel signals.
The foregoing and/or other aspects of the present general inventive concept may also be achieved by providing a karaoke system comprising an audio source generation unit to generate an audio source as left and right channels, a decoder unit to decode the audio source generated in the audio source generation unit according to a predetermined signal format, and a vocal canceling unit to feed-forward-cross mix the left and right channel input signals decoded in the decoder unit with a predetermined delay to generate left and right channel signals, to feedback-cross mix the mixed left and right channel signals with a predetermined delay to generate second left and right channel signals, to low-pass filter the second left and right channel signals, and to mix the low-pass filtered left and right channel signals of low frequency components, and a high frequency component of a difference between the second left and right channel signals.
The foregoing and/other aspects of the present general inventive concept may also be achieved by providing a method of canceling a vocal component, the method comprising delaying one channel signal of left and right channel input signals and canceling a vocal component by feed-forward cross mixing the delayed left and right channel input signals with the right and left channel input signals in order to cancel a portion of the vocal component, delaying the left and right channel signals and widening a sound stage by feedback-cross summation of the delayed left and right channel signals with the right and left channel signals in order to widen the sound stage, and low-pass filtering the output left and right channel signals and canceling a second portion of the vocal component by mixing the low-pass filtered left and right channel signals having low frequency components, and a high frequency component of a difference between the left and right channels in order to cancel a second portion of the vocal component.
The foregoing and/other aspects of the present general inventive concept may also be achieved by providing a computer readable recording medium containing computer readable codes to perform a method, the method including delaying left and right channel input signals and feed-forward cross mixing the delayed channel input signals with the right and left channel input signals to cancel a first vocal component from the left and right channel input signals to generate left and right channel signals, delaying the left and right channel signals and feedback-cross mixing the delayed left and right channel input with the left and right signals to widen a sound stage to generate second left and right channel signals, and low-pass filtering the second left and right channel signals and the mixing the low-pass filtered second left and right channel signals of low frequency components and a high frequency component of a difference between the second left and right channels to cancel a vocal component to generate final left and right channel signals.
The foregoing and/other aspects of the present general inventive concept may also be achieved by providing an apparatus to cancel a vocal component from an audio signal, including a first vocal canceling unit to delay or gain control left and right channel input signals and to add the delayed or gain-controlled left and right channel input signals to the right and left channel input signals, respectively, to generate left and right channel signals, and a second vocal canceling unit to obtain low frequency components from the left and right channel signals, to obtain a high frequency component from a difference between the left and right channel signals, and to add the high frequency component to each of the low frequency components of the left and right channel signals to generate final left and right channel signals.
The foregoing and/other aspects of the present general inventive concept may also be achieved by providing an apparatus to cancel a vocal component from an audio signal, the apparatus including a sound stage widening unit to delay or gain-control left and right channel signals and to add the delayed or gain-controlled left and right channel signals to the right and left channel signals to generate second left and right channel signals, and a vocal canceling unit to obtain low frequency components from the second left and right channel signals, to obtain a high frequency component from a difference between the second left and right channel signals, and to add the high frequency component to each of the low frequency components of the second left and right channel signals to generate final left and right channel signals.
The foregoing and/other aspects of the present general inventive concept may also be achieved by providing an apparatus to cancel a vocal component from an audio signal, the apparatus including a first vocal canceling unit to cancel a first vocal component from left and right channel input signals to generate left and right channel signals, a sound stage widening unit to widen a sound stage of the left and right channel signals to generate second left and right channel signals, and a second vocal canceling unit to cancel a second left and right channel signals to generate final left and right channel signals of an audio signal.
These and/or other aspects and advantages of the present general inventive concept will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
Reference will now be made in detail to the embodiments of the present general inventive concept, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the present general inventive concept by referring to the figures.
Referring to
A decoder unit 220 decodes the left and right channel audio source signals generated in the audio source generation unit 210 according to a signal format such as the MP3 format, and outputs signals as pulse coded modulation (PCM) data.
A vocal canceling unit 230 cancels a first vocal component of the left and right channel input signals decoded in the decoder unit 220 through a feed-forward cross mixing structure having a gain and delay, widens a stereo sound stage of a signal in which the first vocal component is canceled through a feedback cross mixing structure, low-pass filters the widened left and right channel signals, and cancels a second vocal component by mixing the low frequency components of the low-pass filtered left and right channels and the high frequency component of the difference between the left and right channels.
A pitch scaling unit 240 adjusts a pitch of the audio signal in which the vocal component is canceled in the vocal canceling unit 230.
An addition unit 250 adds a voice signal input through a microphone 270 and an analog-to-digital converter (ADC) unit 280 to the audio signal output from the pitch scaling unit 240 to generate a digital audio signal.
A digital-to-analog converter (DAC) unit 260 converts the digital audio signal output from the addition unit 250 into an analog audio signal having the two channels, for example, left and right channels.
A left speaker 292 and a right speaker 294 reproduce the left and right channel analog audio signals, respectively, output from the DAC unit 260.
Referring to
The first vocal canceling unit 310 has a feed-forward cross mix structure having a delay value (Z−n) of a short length, and a gain value (G0). The first vocal canceling unit 310 delays each of the left and right channel input signals for a short time and feed-forward cross mixes the signal of each delayed channel with the input signal of the other channel to cancel a first vocal component therefore to generate left and right channel signals.
The sound stage widening unit 320 has a feedback cross mix structure having a second delay value (Z−n) of an appropriate length, and a second gain value (G1). The sound stage widening unit 320 delays each of the left and right channel signals output from the first vocal canceling unit 310 for an appropriate time and feedback cross mixes the signal of each delayed channel with the input signal of the other channel to widen a sound stage of the left and right channel signals.
The first vocal canceling unit 310 and the sound stage widening unit 320 lower a low frequency component and raise a high frequency component. Accordingly, since the increase in the high frequency component (for example, 3 kHz) increases clearness of the vocal component, a frequency component greater than or equal to a predetermined frequency should be restricted through a low pass filter. Also, since low-pass filtered left and right channel signals lower realism of the sound and a stereo widening effect, a high frequency component of a signal obtained according to a difference between the left and right channel signals is added to the low-pass filtered left and right channel signals. That is, the second vocal canceling unit 330 low-pass filters the left and right channel signals output from the sound stage widening unit 320 and mixes the low frequency components of the low-pass filtered left and right channels with the high frequency component of the difference between the left and right channel signals.
Referring to
In order to adjust a gain reduction of a voice band, first and second gain adjusters 411 and 413 adjust gains of signals input to left and right channels L and K, respectively. The first and second gain adjusters 411 and 413 have predetermined gain values (G0).
In order to leave the high frequency component and low frequency component included in a voice band, first and second delay units 412 and 414 delay the left and right channel input signals whose gains are adjusted in the first and second gain adjusters 411 and 413, for a predetermined time. The first and second delay units 412 and 414 may have short delay values (Z−n) of 1 to 2 sampling times of the left and right channel input signals.
A first left subtracter 416 subtracts the gain-adjusted and delayed right channel input signal from the left channel input signal. A first right subtracter 418 subtracts the gain-adjusted and delayed left channel input signal from the right channel input signal.
Accordingly, the first vocal canceling unit 310 cancels a component having a high similarity between channels with respect to time. The first vocal canceling unit 310 cancels only a stationary component, that is, the vocal component, by obtaining the difference between the two channels using a technique of cross mixing with a short delay. Accordingly, an unstationary (or non-identical characteristic) component is not canceled in the first left subtracter 416 and the first right subtracter 418 such that a sound stage can be widened.
The sound stage widening unit 320 will now be explained.
Third and fourth gain adjusters 421 and 423 adjust gains of the signals input to the left and right channels.
The third and fourth gain adjusters 421 and 423 have second predetermined gain values (G1).
Third and fourth delay units 422 and 424 delay the left and right channel input signals whose gains are adjusted in the third and fourth gain adjusters 421 and 423 for a predetermined time. The third and fourth delay units 422 and 424 may have delay values (Z-m) longer than those of the delay units 412 and 414 of the first vocal canceling unit 310.
A second left adder 426 adds the left channel signal and the gain-adjusted and delayed right channel signal. A second right adder 428 adds the right channel input signal and the gain-adjusted and delayed left channel signal.
Accordingly, by cross mixing the two channel signals with an appropriate delay, the sound stage widening unit 320 slightly widens the sound stage, which is narrowed in the first vocal canceling unit 310. The delay value (Z−m) may be longer than the delay value in the first vocal canceling unit 310 so that a sufficient sound stage can be obtained.
The second vocal canceling unit 330 will now be explained.
A left and right subtracter 430 cancels a vocal component by performing subtraction of the left channel signal and the right channel signal output from the sound stage widening unit 320.
A high pass filer 432 passes the high frequency component of the signal output from the left and right subtracter 430.
A left low pass filter 431 passes a low frequency component in order to restrict the high frequency component of the left channel signal output from the sound stage widening unit 320. Accordingly, the left low pass filter 431 can cancel a sufficient vocal component by reducing clearness caused by the high frequency component.
A right low pass filter 433 passes a low frequency component in order to restrict the high frequency component of the right channel signal output from the sound stage widening unit 320. Accordingly, the right low pass filter 431 can cancel a sufficient vocal component by reducing the clearness caused by the high frequency component.
Fifth, sixth, and seventh gain adjusters 434, 435, and 436 adjust gains of signals output from the left low pass filter 431, the high pass filter 432, and the right low pass filter 433, respectively. The fifth, sixth, and seventh gain adjusters 434, 435, and 436 have respective predetermined gain values (G2, G3, G2).
In order to increase realism of the sound and the wide stereo effect, a third left adder 437 adds a signal output from the fifth gain adjuster 434 of a low frequency band to a signal output from the sixth gain adjuster 435 of a high frequency band, and outputs a final left channel signal (L′).
In order to increase the realism of the sound and the wide stereo effect, a third right adder 437 adds a signal output from the seventh gain adjuster 436 of a low frequency band to a signal output from the sixth gain adjuster 435 of a high frequency band, and outputs a final right channel signal (R′).
Accordingly, the third left adder 437 and the third right adder 438 increase the realism of the sound and the wide stereo effect, by mixing the low-pass filtered signal with a high frequency component of the difference between the two channels.
The present general inventive concept can also be embodied as computer readable codes on a computer readable recording medium. The computer readable recording medium is any data storage device that can store data which can be thereafter read by a computer system. Examples of the computer readable recording medium include read-only memory (ROM), random-access memory (RAM), CD-ROMs, magnetic tapes, floppy disks, optical data storage devices, and carrier waves (such as data transmission through the Internet). The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.
According to the present general inventive concept, the vocal canceling apparatus may be constituted with the first vocal canceling unit to delay or gain control left and right channel input signals and to add the delayed or gain-controlled left and right channel input signals to the right and left channel input signals, respectively, to generate left and right channel signals, and the second vocal canceling unit to obtain low frequency components from the left and right channel signals, to obtain a high frequency component from a difference between the left and right channel signals, and to add the high frequency component to each of the low frequency components of the left and right channel signals to generate final left and right channel signals in which the vocal component of the left and right channel input signals has been removed.
It is possible that the vocal canceling apparatus may be constituted with the sound stage widening unit to delay or gain-control left and right channel signals and to add the delayed or gain-controlled left and right channel signals to the right and left channel signals to generate second left and right channel signals, and the second vocal canceling unit to obtain low frequency components from the second left and right channel signals, to obtain a high frequency component from a difference between the second left and right channel signals, and to add the high frequency component to each of the low frequency components of the second left and right channel signals to generate final left and right channel signals, in which the vocal component of the left and right channel input signals has been removed.
Although the present embodiment illustrates the two channel input signals and two final channel signals, the present general inventive concept is not limited thereto. It is possible to generate three or more final channel signals using two or more channel input signals in the vocal cancelling apparatus of an audio system, such as the karaoke system.
Although a few embodiments of the present general inventive concept have been shown and described, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the general inventive concept, the scope of which is defined in the appended claims and their equivalents.
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