JP2591472Y2 - Sound signal processing device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acoustic signal processing apparatus which is particularly suitable for sound field expansion processing such as a live broadcast of music or sports centering on vocals.

[0002]

2. Description of the Related Art As shown in FIG. 10, for example, a conventional acoustic signal processing apparatus 100 has a left channel (hereinafter, Lch) input terminal 101 and a right channel (hereinafter, Rch).
That. ) Input terminal 102 and adders 103 to 105
, A phase shift circuit 106, and Lch and Rch output terminals 107 and 108.

The Lch and Rch input terminals 101, 1
02 from the adder 103
And are added to each other. The output signal of the adder 103 is input to the phase shift circuit 106 and the phase is shifted by a predetermined angle.
The sound signal is added to the sound signal.
It is subtracted from the sound signal. Then, the output of the adder 104 is taken out from the Lch output terminal 107, and the output of the adder 105 is taken out from the Rch output terminal.

As described above, the sum of the Lch and Rch signals is phase-shifted, and the phase-shifted signal is added to the Lch signal and subtracted from the Rch signal to finally provide a speaker (not shown). A sound whose sound field is enlarged in a more audible sense is reproduced.

FIG. 11 shows a frequency characteristic diagram of an output signal of the conventional processing device 100. That is, the output signals of the Lch and the Rch are shifted in phase from each other, and have a substantially comb-shaped waveform. This characteristic is a general characteristic of pseudo stereo.

[0006]

[Problem to be solved by the invention] However, this device 1
In the case of 00, a human voice included in the input acoustic signal (hereinafter, referred to as
It is called human voice. ) And the residual signal excluding this human voice component have been processed by the same phase shift circuit 106, so that peaks and dips occur in the waveforms of the Lch and Rch signals in the human voice frequency band v, There are problems that the voice sounds unnatural, and particularly in a sound field expansion circuit or the like using a delay element, the voice is heard twice and it becomes difficult to hear.

In a live broadcast of a baseball game on a television, the surrounding sound of the spectator may be transmitted as a stereo signal, and only the human voice of an announcer may be transmitted as a monaural signal. In such a case, it is preferable that the surrounding audio information that gives an atmosphere of support or the like be reproduced sufficiently after sound field expansion processing (for example, so-called surround processing), but it is preferable that the human voice of the announcer be clearly heard. . Therefore, it was easier to hear the human voice signal without the sound field expansion processing. However, conventionally, even in such a case, there is a disadvantage that the human voice is difficult to be heard because the human voice is uniformly subjected to the sound field expansion processing together with the surrounding voice.

It is an object of the present invention to provide an acoustic signal processing apparatus capable of obtaining an effect of expanding a sound field without substantially reducing the clarity of a human voice.

[0009]

Means for Solving the Problems] To solve the above problems
The present invention provides a human voice extracting means for extracting a human voice frequency band signal from a plurality of audio signals, a signal comparing means for comparing the human voice frequency band signal level with a predetermined level, and a comparison result of the signal comparing means. Switch means for opening and closing based on
Sound field expansion processing means for performing sound field expansion processing on the acoustic signal,
Signal adding means for adding the sound field-expanded sound signal and the human voice frequency band signal input via the switch means, and when the level of the human voice frequency band signal exceeds a predetermined level, The switch means is closed and the human voice frequency band signal is input to the signal adding means.If the level of the human voice frequency band signal is equal to or lower than a predetermined level, the switch means is opened and the human voice frequency band signal is transmitted. It is characterized in that it is not input to the signal adding means.

[0010]

[Action] acoustic signal is directly sound field expansion process. On the other hand, a human voice frequency band signal is extracted from the acoustic signal, and the signal level is compared with a predetermined level. When the signal level exceeds a predetermined level, the switch means is closed, and the human voice frequency band signal and the sound field expanded sound field are added. Therefore, in this case, the sound signal subjected to the sound field expansion processing and the human voice frequency band signal not subjected to the sound field expansion processing are simultaneously reproduced. When the signal level is equal to or lower than the predetermined level, the switch is opened, and the human voice frequency band signal is not added to the sound signal whose sound field is expanded. Therefore, in this case, only the sound signal subjected to the sound field expansion processing is reproduced.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a configuration diagram of a first embodiment of an audio signal processing device according to the present invention. In FIG. 1, the acoustic signal processing device 1 includes Lch and Rch acoustic signals S1 and S2.
And a sound field expansion processing circuit (sound field expansion circuit) for inputting the Lch and Rch residual signals S11 and S12 of the output signal of the extraction circuit 2 excluding the human voice component. Enlargement processing means) 3 and Lch of this processing circuit 3
And a signal adding circuit (signal adding means) 4 for inputting the Rch output signals S21 and S22, and a human voice component S3 of the output signal of the human voice extracting circuit 2 is input to the signal adding circuit 4. . And the signal addition circuit 4
From the output side of the Lch and Rch output signals S31 and S32
Is output.

That is, only the residual components S11 and S12 are input to the sound field expansion processing circuit 3 and are subjected to sound field expansion processing.
In this embodiment, the Lch and Rch signals are used as the plurality of sound signals. However, the present invention is not limited to the Lch and Rch signals, and it goes without saying that any two sound signals can be used. Further, a configuration may be employed in which three or more acoustic signals are used.

Next, each circuit constituting the device 1 will be described. FIG. 2 is a configuration diagram of the human voice extraction circuit 2 according to the first embodiment. The extraction circuit 2 includes adders 21 and 22 provided on the input sides of Lch and Rch, respectively, and a band-pass filter (hereinafter, referred to as an output) of the adder 22.
It is called BPF. ) 23, an adder 24, and the adder 2
1 and an adder 25 provided on the output side of the adder 24, respectively.
5, 26 and the output signal S1 from the output side of the BPF 23.
1, S12 and S3 are taken out.

The BPF 23 is a filter mainly for passing a human voice band, in this embodiment, a pass band of 150 Hz.
Although a filter having a characteristic of 1 kHz to 1 KHz is used, the present invention is not limited to this characteristic, and another filter may be used as long as the filter mainly passes the human voice band.

That is, the Lch and Rch sound signals are added by the adder 22 and the added output is added to the BPF 23
Only the human voice frequency band signal S3 is extracted, and this signal S3
Is input to the adder 24, and is subtracted from the output signal of the adder 22. Therefore, a residual signal excluding the human voice band is obtained as an output signal of the adder 24. The residual signal is further input to adders 25 and 26, where the adder 25 adds the output signal of the adder 21 and the adder 26 subtracts the output signal of the adder 21. As a result, Lch and Rch residual signals S11 and S12 are obtained as output signals of the adders 25 and 26, respectively.

FIG. 3 is a configuration diagram of the sound field expansion processing circuit according to the first embodiment. The sound field expansion processing circuit 3 includes Lch and R
an adder 31 for adding the remaining signals S11 and S12 of the channel;
Four delay circuits 3 for inputting the output signal of the adder 31
2 to 35, an adder 36 for adding the output signals of the delay circuits 32 and 33, an adder 37 for adding the output signals of the delay circuits 34 and 35, the output signal of the adder 36 and the residual signal An adder 38 for adding S11 and an adder 39 for adding the output signal of the adder 37 and the residual signal S12 are provided.
Output signals S21 and S22 are taken out from the output side of.
That is, the residual signals S11,
Since the sound field expansion processing is performed by adding and delaying the two signals in S12, the sound field expansion processing hardly affects the human voice band components.

FIG. 4 is a configuration diagram of the signal addition circuit according to the first embodiment. The signal addition circuit 4 includes Lch and Rch addition circuits 41 and 42. That is, the residual signals S21 and S22 having the sound field expanded are added to the human voice signal S3 by the adders 41 and 42, respectively, and the human voice band components are hardly lost as output signals of the adders 41 and 42. Lch and Rch sound signals S31 and S32 with the sound field expanded
Is obtained.

FIG. 5 is a block diagram of another example of the human voice extracting circuit according to the first embodiment. The human voice extraction circuit 5 includes Lch and R
BPFs 51 and 52 are provided for the respective channels, and the output signals are added to the signals S1 and S2 by adders 53 and 54, respectively. With this configuration, the human voice band component and the residual signal are separated into signals S8, S9 and S1 respectively for Lch and Rch.
1, S12.

As described above, as shown in the frequency characteristic diagram of the output signal in FIG. 6, the phase of the human voice band portion v hardly changes, and the phase of only the remaining components is shifted. Is mainly performed only on the remaining components.

Therefore, for example, a sound field expansion process using background sounds, musical instrument sounds, and the like without impairing the audibility of a human voice included in the original sound signal or losing the sound quality of a singing voice. It becomes possible to do.

FIG . 7 is a block diagram of a second embodiment of the acoustic signal processing apparatus according to the present invention. In FIG. 7, an audio signal processing device 60 includes a human voice extraction circuit (human voice extraction means) 61 for inputting Lch and Rch audio signals S1 and S2, a diode D1 for rectifying the extracted human voice frequency band signal, and this diode A signal comparison circuit (signal comparison means) 62 for comparing the output level of D1 with a predetermined level, and a relay (switch means) 6 which opens and closes based on the comparison result of the comparison circuit 62
3, a sound field expansion processing circuit (sound field expansion processing means) 64 for performing sound field expansion processing on the sound signals S1 and S2, and the sound field expanded sound signals S71 and S72 and the input through the relay 63. A signal addition circuit (signal addition means) 65 for adding the human voice frequency band signal S73 to the Lch and Rch output signals S
81 and S82 are output.

Next, each circuit constituting the device 60 will be described. The illustration and description of the sound field expansion processing device 64 and the signal addition circuit 65 are omitted because they are the same as those in the first embodiment. FIG. 8 is a configuration diagram of a human voice extraction circuit according to the second embodiment. This extraction circuit 61 includes Lch and Rc
The adder 66 adds the h acoustic signals S1 and S2, and a BPF 67 provided on the output side of the adder 66. The human voice frequency band signal S73 is output from the output side of the BPF 67.

When a signal obtained by synthesizing a stereo signal and a monaural signal is transmitted, as in the case of a live broadcast of baseball, etc., when this signal is added by the adder 66, the signal after the addition is processed. The output level is generally higher than when only a stereo signal is used. This is monaural signal Lc
This is because the signal level and the phase of h and Rch are substantially equal, so that when added, the level becomes relatively high. Therefore,
From the magnitude of the output level of the adder 66, it is possible to determine whether or not this signal contains a monaural signal.

The diode D1 is for rectifying the extracted human voice frequency band signal S73. The rectified human voice frequency band signal is input to the signal comparison circuit 62. This comparison circuit 62 can be constituted by a conventional comparator. Further, if the threshold value is appropriately selected, it is also possible to constitute a gate circuit. As the predetermined level signal, a voltage of a relatively high level is set in advance so that a monaural signal can be determined, and is applied to a predetermined level signal input terminal.

The opening and closing of the relay 63 is controlled by the output signal of the comparison circuit 62. That is, when a voltage exceeding a predetermined level is input to the comparison circuit 62, the comparison circuit 6
2 outputs a high level (H) signal, and the relay 63 is closed. Therefore, the extracted human voice frequency band signal S7
3 is input to the signal addition circuit 65, and as the output signals S81 and S82 of the signal addition circuit 65, for example, the sound surrounding the audience and the like who has increased the sense of reality due to the sound field expansion processing and the sound field expansion processing are clear. The voice of the announcer with high degree and localized in the center can be obtained at the same time.

On the other hand, when a signal of a predetermined level or less is input to the comparison circuit 62, a low level (L) signal is output from the comparison circuit 62 and the relay 63 is opened. Therefore, the extracted human voice frequency band signal S73 is not input to the signal addition circuit 65, and the sound field expansion processing circuit 64
Only the output signals S71 and S72 of the
As output signals S81 and S82. For example, both the surrounding sound of the audience and the sound of the announcer are subjected to sound field expansion processing and output from the signal adding circuit 65.

As described above, when the level of the human voice frequency band signal is relatively high (for example, a monaural signal), this signal is output without performing sound field expansion processing. As shown in the figure, the surrounding sound of the audience etc. by the stereo signal is sufficiently expanded in the sound field to improve the sense of reality, and the human voice of the announcer (v in the figure) by the monaural signal is improved in clarity and localized in the center. Can be done. That is, the device 60 is characterized in that the sound field expansion processing is performed when the sound of the announcer is a stereo signal, and the sound field expansion processing is not performed when the sound of the announcer is a monaural signal.
For example, this is particularly effective when watching a program in which stereo sound and monaural sound are synthesized, such as a live broadcast of baseball.

Also, since a function of expanding the sound field of the original audio signal regardless of whether or not monaural sound is included is also provided, the sound signal is expanded compared to the case where the remaining signal excluding the human voice signal is expanded. There is also an effect that the field expansion effect can be improved.

[0029]

According to the present invention , a decision is made as to whether or not the sound field expansion processing should be performed on the basis of the levels of a plurality of human voice frequency band signals. For example, when this signal is a monaural signal, It is possible to configure so as not to perform the sound field expansion processing. Therefore, in the case of a signal in which a stereo signal and a monaural signal are combined, the synthesized signal is subjected to sound field expansion processing to enhance the sense of reality, and the monaural signal can be reproduced without the sound field expansion processing, so that clarity is increased. , Can be localized at the center.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a first embodiment of an audio signal processing device according to the present invention.

FIG. 2 is a configuration diagram of a human voice extraction circuit 2 according to the first embodiment.

FIG. 3 is a configuration diagram of a sound field expansion processing circuit according to the first embodiment.

FIG. 4 is a configuration diagram of a signal addition circuit according to the first embodiment.

FIG. 5 is a configuration diagram of another example of the human voice extraction circuit according to the first embodiment.

FIG. 6 is a frequency characteristic diagram of an output signal of the first embodiment.

FIG. 7 is a configuration diagram of a second embodiment of the audio signal processing device according to the present invention.

FIG. 8 is a configuration diagram of a human voice extraction circuit according to a second embodiment.

FIG. 9 is a frequency characteristic diagram of an output signal of the second embodiment.

FIG. 10 is a configuration diagram of a conventional acoustic signal processing device.

FIG. 11 is a frequency characteristic diagram of an output signal of a conventional acoustic signal processing device.

[Explanation of symbols]

1, 60: sound signal processing device, 2, 61: human voice extraction circuit (human voice extraction means), 3, 64: sound field expansion processing circuit (sound field expansion processing means), 4, 65 ... Signal addition circuits (signal addition means) 21, 22, 24 to 26, 31, 36 to
39, 41, 42, 53, 54 ... adders, 23, 5
1, 52 ... bandpass filter (BPF), 32 to 3
5 delay circuit, 62 signal comparison circuit (signal comparison means), 63 relay (switch means), D1 diode.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-49-59605 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H04S 1/00 H04S 7/00

Claims (1)

(57) [Scope of request for utility model registration] A human voice extracting means for extracting a human voice frequency band signal from a plurality of acoustic signals, a signal comparing means for comparing the human voice frequency band signal level with a predetermined level, and a comparison result of the signal comparing means. Switch means for opening and closing based on
Sound field expansion processing means for performing sound field expansion processing on the acoustic signal,
Signal adding means for adding the sound field-expanded sound signal and the human voice frequency band signal input via the switch means, and when the level of the human voice frequency band signal exceeds a predetermined level, The switch means is closed and the human voice frequency band signal is input to the signal adding means.If the level of the human voice frequency band signal is equal to or lower than a predetermined level, the switch means is opened and the human voice frequency band signal is transmitted. An acoustic signal processing device wherein the signal is not input to a signal adding means.