JPH08331697A - Sound information converter - Google Patents

Abstract

PURPOSE: To create the sound field which is close to a natural sound source by converting tone color and sound quality, by setting an arbitrary frequency band characteristic without distorting original sound, giving the spreading feeling of a sound image and adding a high frequency band component in a pseudo manner. CONSTITUTION: After a sound dividing and synthesizing part 3 divides the sound band of a stereo signal into plural bands and makes the bands into prescribed levels, the part 3 raises the levels of the frequency components of a low-frequency sound band and a high frequency band for an intermediate frequency band by synthesizing the signal of each divided band. A sound field conversion part 4 changes the fixed position of a sound image and imparts the spreading feeling of the sound image by inverting the phase of the signal of an opposite channel and adding this signal to the output of the sound dividing and synthesizing part 3 after the signal is attenuated to a prescribed level. Further, a high frequency band signal generation part 5 extracts 10 to 20kHz components, for instance, from the output of the sound field conversion part 4, generates 20 to 40kHz components by a harmonic sound generation circuit, and adds the components to the output of the sound field conversion part. Thus, the reproduction of frequency components of 20kHz or more, the spreading feeling, the stereoscropic effect and the presence of sound can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an audio information conversion device capable of arbitrarily setting the sound quality characteristics of left and right stereo audio signals.

[0002]

2. Description of the Related Art In particular, in a compact disc digital recording / reproducing system, the upper limit of the recording frequency band is about 2.
Since the frequency is 0 kHz, the high frequency component of 20 kHz or higher is not recorded on the recording medium, so that the high frequency component of 20 kHz or higher is not reproduced at the time of reproduction. However, it is difficult for humans to hear 2
It is said that a high frequency component of 0 kHz or higher has an effect of stimulating a brain wave of a listener to generate an α wave in a music appreciation and the like to make the user feel comfortable and relaxed. Therefore, when listening to music, it is preferable that the reproduced sound contains high-frequency components like an analog record.
In particular, the compact disc digital recording / reproducing system has a drawback that it does not include high frequency components as described above.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to eliminate the drawbacks of the conventional example and to provide a sense of sound image spread without distorting the original sound. At the same time, a high frequency component related to the original sound is artificially added to create a sound field close to a natural sound source,
Therefore, the present invention is to provide a voice information conversion device having a stereoscopic effect and a realistic feeling.

[0004]

A voice information conversion apparatus according to the present invention divides a voice band of a stereo signal into a plurality of bands to obtain a predetermined level and synthesizes the signals of the respective divided bands. After inverting the phase of the split-synthesis unit and the signal of the opposite channel and attenuating to a predetermined level,
A sound field converter that adds this signal to the output signal of the voice division synthesizer, and a specific frequency component generated from the output signal of the sound field converter, and a high frequency that adds this signal to the output signal of the sound field converter. It is characterized in that it is configured with a range signal generation unit.
In addition, the high frequency signal generation unit extracts a predetermined frequency component from the output signal of the sound field conversion unit through the filter, converts this frequency component into a double frequency by the harmonic overtone generation circuit, and converts the converted frequency component. Is added to the output signal of the sound field converter. In addition, the high frequency signal generation unit extracts a predetermined frequency component from the output signal of the sound field conversion unit via the filter, and the frequency component is increased to n (n = 3 to 5) times the frequency by the n-th overtone generation circuit. It is characterized in that the frequency component is converted and the converted frequency component is added to the output signal of the sound field converter.

[0005]

According to the present invention, there is provided the audio division / synthesis unit to which the left and right stereo audio signals are supplied. The audio division / synthesis unit has a low-pass filter with a cutoff frequency of about 100 Hz, a bandpass filter, and a cutoff frequency. About 10
The original sound is divided into three parts with a high-pass filter of kHz, and this 3
The level of the frequency component of the low frequency range and the frequency component of the high frequency range of each of the divided frequency bands is increased with respect to the middle frequency range. Then, the respective frequency components are combined by the adder and supplied to the sound field conversion unit.

The sound field converter is connected from the right channel audio signal circuit to the adder of the left channel audio signal circuit via the first phase inversion circuit and the first level adjuster, and vice versa. The signal circuit is connected to the adder of the right channel audio signal circuit through the second phase inversion circuit and the second level adjuster, and the first and second level adjusters are adjusted by the control signal of the variable operation terminal. Then, the localization of the sound image can be changed (sound image localization changing means) to give a sense of expanse of the sound image. Furthermore, about 10 kHz to 20 of the original sound
By extracting a specific frequency component of kHz by a bandpass filter and supplying the extracted specific frequency component to a harmonic overtone generation circuit, a high frequency component of approximately 20 kHz to 40 kHz can be generated. By adding to the audio output via the adder, it is possible to hear a frequency band component of approximately 20 kHz or more during reproduction.

As described above, the audio information converting apparatus emphasizes the low-pitched sound range and the high-pitched sound range, and adds pseudo high-frequency components, so that the compact disc has a frequency of 20 Hz or less.
Alternatively, even if the frequency component of 20 kHz or higher is not included, the low frequency range is appropriately emphasized, and the frequency component of 20 kHz or higher is reproduced, so that a sound spread feeling, a stereoscopic effect, and a realistic feeling can be obtained.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a voice information conversion device according to the present invention will be described based on the block diagram of FIG. In the figure, 1
Is an input terminal of a left channel (hereinafter referred to as Lch) of a stereo audio signal, 2 is an input / output selector switch, and 2a
Is a changeover switch on the input side, 2b is a changeover switch on the output side, and 3 is a voice division / synthesis unit.
Is a low-pass filter 3 with a cut-off frequency of 100 Hz
a (hereinafter referred to as LPF3a), a band pass filter 3b (hereinafter referred to as BPF3b), and a high pass filter 3c having a cutoff frequency of 10 kHz (hereinafter referred to as HPF3).
and a level adjuster 3d is connected to the output side of the LPF 3a, a level adjuster 3e is connected to the output side of the BPF 3b, and a level adjuster 3f is connected to the output side of the HPF 3c. This level adjuster 3d, 3
e and 3f can be continuously varied by a control signal from the variable operation terminal 3g. 3h is an adder for synthesizing the respective signals divided into three.

Reference numeral 4 denotes a sound field conversion unit, and this sound field conversion unit 4
From the first phase inversion circuit 4a connected to Rch
Is supplied to the adder 4c via the level adjuster 4b of
The Rch phase inversion signal and the original Lch audio signal are added, and the level adjuster 4b is adjusted by the control signal supplied to the variable operation terminal 4d, whereby the sound field conversion of the Lch stereo signal can be performed. 5 is a high frequency signal generation unit, and the high frequency signal generation unit 5 is approximately 10 kHz to 20 kHz.
A bandpass filter 5a for extracting a signal component in a specific frequency band of kHz, a harmonic overtone generation circuit 5b for overtone processing the output signal of the bandpass filter 5a, and a level adjuster 5c provided on the output side of the overtone generation circuit 5b. An operation terminal 5d for controlling the level adjuster 5c, the band pass filter 5a, the overtone generation circuit 5b, and the level adjuster 5
line 5e for bypassing c and the level adjuster 5c
Of the bypass line 5e and the output signal of the bypass line 5e.

Reference numeral 6 is a bypass line for bypassing the voice information conversion function connected to the input / output changeover switches 2a and 2b, and 7 is an output terminal. Further, reference numerals 11 to 17 are reference numerals of respective parts of the Rch circuit of the stereo audio circuit.
The configuration of the h circuit is the same as that of the Lch circuit described above, and the numbers in the last digit of 11 to 17 are the same as the reference symbols of the respective parts of the Lch circuit, and the description thereof will be omitted.

In the audio information conversion device thus configured, the L / Rch signals of the stereo audio signal are input terminals 1 and 1, respectively.
1 is supplied. Hereinafter, since the L / Rch signal processing is the same, only the Lch signal processing will be described. When the Lch signal is supplied to the input terminal 1, the Lch signal is selected by performing the audio information conversion function by the interlocked input / output changeover switches 2a and 2b or by outputting the audio information conversion function by bypassing. To be done. Generally, when listening to stereo sound such as music, you can enjoy more powerful and realistic music by activating the voice information conversion function, but avoid adding the voice information conversion function to the original sound. This voice information converter can be bypassed if it needs to be transmitted.

As shown in the figure, the input / output changeover switches 2a, 2
When b is set to operate the audio information conversion function, the input Lch signal is supplied to the audio division / synthesis unit 3. The Lch signal supplied to the voice division / synthesis unit 3 is LPF3a, BPF3b, H of a predetermined cutoff frequency.
It is divided into three by the PF 3c, and the level of each frequency band can be arbitrarily set by the level adjusters 3d, 3e, 3f for each of the three divided frequency bands. Specifically, 100 Hz passed through LPF3a
The following low frequency components and 1 which passed through HPF3c
It is set so that the frequency components in the high frequency range of 0 kHz or higher are increased with respect to the mid frequency range of the BPF 3b. Then, the original sound becomes a stereo audio signal having the frequency characteristic desired by the listener by synthesizing the signal components of the respective bands, which are divided into three and whose levels are adjusted, by the adder 3h.

Next, the above-mentioned Lch signal is converted into a sound field conversion unit 4
Is supplied to the adder 4c. On the other hand, the Rch signal whose phase has been inverted by the first phase inversion circuit 4a from the Rch stereo audio signal circuit is supplied to the adder 4c via the first level adjuster 4b. As a result, it is possible to obtain a feeling of expansion of the stereo audio signal.

Further, the Lch signal is supplied to the high frequency signal generator 5, a specific frequency component of about 10 kHz to 20 kHz is extracted by the band pass filter 5a, and the extracted specific frequency component of about 10 kHz to 20 kHz is overtone-generated. By supplying to the circuit 5b, approximately 20 kHz-40
A high frequency component of kHz can be generated. The harmonic overtone generating circuit 5b is composed of a well-known absolute value circuit (not shown) that is generally used, and this absolute value circuit performs full-wave rectification using an ideal diode circuit and outputs it through an adding circuit. This is to obtain a double frequency signal, and it is possible to accurately generate an overtone of the input audio signal. That is, the output signal of the harmonic overtone generation circuit 5b is adjusted by the level adjuster 5c and supplied to the adder 5f, while the Lch signals of the entire band from the bypass line 5e are added by the adder 5f, so that an Lch stereo output is obtained. The frequency band of the signal is about 40
A high frequency component extended to kHz can be obtained.

As described above, the Lch output signal includes the 20
By artificially adding a high frequency component of kHz or higher, it is possible to add an unreproducible high frequency component which is not recorded in the digital recording medium to the reproduced audio signal when the digital recording / reproducing system is reproduced. it can.

In the above embodiment, the high frequency signal generator extracts a predetermined frequency component from the output signal of the sound field converter through the filter, and this harmonic component is doubled by the harmonic overtone generation circuit. Although the conversion is performed and the converted frequency component is added to the output signal of the sound field conversion unit, the high frequency signal generation unit extracts a predetermined frequency component from the output signal of the sound field conversion unit through the filter. At the same time, this frequency component may be converted into a frequency of n (n = 3 to 5) times by the n-th overtone generation circuit, and the converted frequency component may be added to the output signal of the sound field converter.
In the present embodiment, the low-frequency range is raised during the reproduction of the low-pitched sound. However, a frequency dividing circuit is further used to obtain a half frequency and generate a frequency component of 20 Hz or less from the original sound. However, if this generated frequency component is added to the original sound, it becomes possible to perform low-pitched sound reproduction with a more realistic feeling.

Although the Lch signal processing has been described above, it goes without saying that the Rch signal processing is similarly processed.
Further, although the frequency characteristic of three divisions has been described in the voice division / synthesis unit 3, the division is not limited to three divisions, and more divisions may be performed. Further, although the overtone generation circuit 5b has been described by using the absolute value circuit, the circuit is not limited to the absolute value circuit and may be any circuit having an accurate overtone generation function.

[0018]

The voice information converting apparatus according to the present invention has a low-frequency component of 100 Hz or less with respect to the middle frequency range and 10 kHz.
In addition to the frequency characteristics emphasizing the high-frequency component, the frequency component of approximately 20 to 40 kHz is added to the high-frequency range, so that stereo reproduction with a stereoscopic effect and a realistic sensation can be realized. Also,
Since the spread of the sound source can be set as desired, the spread of the stereo playback sound can be obtained, and in particular, the installation positions of the left and right speakers of the radio-cassette, car-mounted audio equipment, etc. are secured at a sufficient distance. In such a system that is difficult to achieve, there is an effect that it is possible to obtain a feeling of sound image spread that is greater than the distance between the speakers.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a voice information conversion device according to the present invention.

[Explanation of symbols]

 1, 11 L / Rch input terminal 2, 12 Input / output changeover switch 3, 13 Voice division synthesis section 3a Low-pass filter (LPF) 3b Band-pass filter (BPF) 3c High-pass filter (HPF) 3d-3f Level adjuster 3g Variable operation Terminal 3h Adder 4,14 Sound field converter 4a First phase inversion circuit 4b First level adjuster 4c Adder 4d Variable operation terminal 5,15 High frequency signal generator 5a Bandpass filter 5b Overtone generator 5c Level Regulator 5d Operation terminal 5e Bypass line 5f Adder 6,16 Bypass line 7,17 Output terminal

Claims (3)

[Claims] 1. A voice division / combination unit configured to divide a voice band of a stereo signal into a plurality of bands to have a predetermined level, and to combine the signals of the respective divided bands, and to invert the phase of a signal of an opposite channel. Then, after attenuating to a predetermined level, this signal is generated by generating a specific frequency component from the sound field conversion unit that adds this signal to the output signal of the voice division synthesis unit and the output signal of the sound field conversion unit. An audio information conversion device comprising a high-frequency signal generation unit that is added to an output signal of the sound field conversion unit. 2. The high frequency signal generation unit extracts a predetermined frequency component from the output signal of the sound field conversion unit through a filter, converts this frequency component into a doubled frequency by a harmonic overtone generation circuit, and performs this conversion. The audio information conversion device according to claim 1, wherein the frequency component is added to the output signal of the sound field conversion unit. 3. The high frequency signal generator extracts a predetermined frequency component from the output signal of the sound field converter through a filter, and the frequency component is n (n = 3) by an n harmonic overtone generation circuit.
To 5) times the frequency, and the converted frequency component is added to the output signal of the sound field conversion unit.