JPH11231865A - Method and device for stereophonic musical sound production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and device for stereophonic musical sound production capable of giving a natural stereophonic feeling with small memory capacity. SOLUTION: This device involves the installation of an oscillation device 101 used for musical sound signal generation, an amplitude control device 102 for controlling the amplitude of a musical sound signal generated with the device 101, a frequency characteristic control device for controlling the frequency characteristic of the musical sound signal, an effect device for processing a musical sound waveform, a digital/analog conversion device and a stereo-audio device. Furthermore, a fluctuation signal generation device 2 is installed for generating two types of fluctuation signals. In this case, the fluctuation signals generated via the device 1 are sent to the amplitude control device 102 where a monophonic musical sound signal is converted into a stereophonic musical sound and then outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for generating a stereo sound which can be used in a sound source system.

[0002]

2. Description of the Related Art An electronic musical instrument having a stereo output has two data of a right waveform and a left waveform, and generates two data separately. Alternatively, the stereo musical sound is generated by changing the monaural waveform data to two different frequency characteristics or phase characteristics and outputting them separately to the right and left sides. Further, a stereo tone is generated by changing and controlling the phase characteristic of the monaural waveform data by using a delay circuit and outputting the monophonic waveform data to the right side and the left side separately. The same can be achieved by shifting the waveform reading start address in the waveform reading sound source.

[0003]

When there are two data of a right waveform and a left waveform for stereo output, the data amount becomes twice as large as that of monaural output, and a large storage capacity is required (for each tone color). More if prepared.) Further, there is a disadvantage that it is difficult to obtain a natural sense of stereo by simply changing the frequency characteristics and the phase characteristics. Further, the configuration using the delay circuit has a problem that it is very difficult to obtain a parameter for obtaining a natural stereo feeling.

The present invention has been made in view of the above problems of the prior art, and has as its object to provide a method and apparatus for generating a stereo musical tone capable of obtaining a natural stereo feeling with a small storage capacity.

[0005]

Therefore, a stereo tone generating method according to the present invention basically comprises adding two or more kinds of fluctuation signals to a monaural tone to generate two or more kinds of tone to be a stereo tone. Features. Here, the fluctuation is a minute fluctuation component of the amplitude and frequency of a sound or musical instrument in the natural world. The amplitude fluctuation can be extracted by removing the amplitude envelope from the temporal change of the amplitude of the musical sound waveform, and the frequency fluctuation can be extracted by removing the frequency envelope from the temporal change of the frequency of the musical sound waveform. In order to remove the monotonousness of the electronic sound and generate a musical sound with a pleasant sensation like a natural sound, it is necessary to give a fluctuation component to the time variation of the amplitude or the frequency variation of the electronic sound. In the above configuration, by utilizing the nature of the above-described fluctuation, a fluctuation signal is added to the monaural sound so that a natural hearing can be obtained, and two or more kinds of fluctuation signals are added to the monaural sound. Thus, it is possible to generate a musical tone to which two or more types of fine fluctuation components of amplitude and frequency are added. For example, when two types of musical sounds are generated, the right waveform and the left waveform are output from separate speakers or the like. As a result, a natural stereo feeling can be obtained. Of course, three or more tones are generated, and monaural tones
It goes without saying that, for example, a configuration may be employed in which a musical tone to which fine fluctuation components are added is emitted from various directions, such as a surround system.

The parameters necessary for generating the fluctuation are the distribution characteristic, the frequency characteristic, and the amplitude characteristic. By changing at least one of them, two or more kinds of fluctuation signals can be generated. If the fluctuation signal generated as described above is added to a monaural tone, a natural feeling of stereo can be obtained.

Further, the configuration of the stereo musical tone generating device according to the third aspect of the present invention comprises an oscillator used for generating at least a musical tone signal, an amplitude control device for controlling the amplitude of the musical tone signal generated thereby, and a frequency of the musical tone signal. A frequency characteristic control device for controlling characteristics, and a musical tone output device for outputting a musical tone, having a configuration for generating a musical tone, and a fluctuation signal generating device for generating two or more types of fluctuation signals,
It is characterized in that these fluctuation signals are added to any one or a plurality of configurations for generating the tone, and the monaural tone signal is output as two or more stereo tones. That is, the configuration of the method of claim 1 is a device configuration. However, a configuration is provided in which a fluctuation signal generating device for generating two or more types of fluctuation signals is provided to generate a musical tone (ie, an oscillation device, an amplitude control device, a frequency The configuration has at least a characteristic control device and a musical sound output device, and an effect device is added as required), and is characterized in that these fluctuation signals are added to any one or a plurality of configurations. Thus, a monaural tone can be changed to a stereo tone. If any one of the oscillation device, the amplitude control device, and the frequency characteristic control device which particularly affects the tone color, or the configuration in which these fluctuation signals are applied to two or more of these configurations, Compared to the configuration provided to the device, a more natural audibility can be obtained.

The parameters necessary for generating the fluctuation are the distribution characteristic, the frequency characteristic and the amplitude characteristic. In the configuration of the stereo tone generator, the fluctuation signal generator is replaced with a random number generator for determining the distribution characteristic. And a frequency characteristic control device such as a filter for controlling frequency characteristics (the fluctuation signal generator of this configuration needs to have at least these two configurations), the initial setting of the random number generator is changed. If two or more types of fluctuation signals are generated in this way, a natural stereo feeling can be obtained by adding these fluctuation signals to the monaural tone, as in the case described above.

Further, the fluctuation signal generator may be constituted by a storage device in which the fluctuation signal is recorded. In that case, by changing the read position, it becomes possible to generate two or more types of fluctuation signals.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a stereo tone generator according to the third aspect of the present invention will be described below. FIG.
FIG. 1 is a block diagram showing an overall circuit configuration when a stereo musical sound generator according to an embodiment of the present invention is used in an electronic musical instrument.

In FIG. 1, an input device 1 is connected to a bus 100.
10, a display device 111, a fluctuation signal generator 1,
Central processing unit 112, storage device 113, oscillation device 1
01, an amplitude control device 102, a musical tone frequency characteristic control device 103, and an effect device 104 are connected, and exchange control signals, address signals, and data between them via the bus 100.

The input device 110 includes various panel switches for control instructions connected via a panel interface, a keyboard for inputting key information according to the performance of a player, a MIDI input device, a pedal, and other components. It has a configuration having switches and a volume, and a panel display serving as an input panel switch may be a part of the device configuration as needed, as described later.

The display device 111 is connected via a panel interface, displays various setting states of the electronic musical instrument, and serves as an input panel switch as an input device of the input device 110 as necessary. It consists of a display.

The central processing unit 112 has a central processing unit CP for performing overall control and arithmetic processing.
U. For example, a part of the control signal is emitted from the central processing unit 112 for setting distribution characteristics, and given to a random number generator of the fluctuation signal generator 1 described later.

The storage device 113 is a ROM for storing data such as programs and distribution tables to be described later.
And an external storage device such as a RAM or a flash memory card or a hard disk drive for temporarily storing necessary data and coefficients.

The oscillating device 101 is provided with a low-frequency oscillator for giving a sawtooth wave, and has a configuration of a sound source LSI having a digitally controlled oscillator serving as an oscillating circuit as a configuration of a waveform generating means for generating a musical tone waveform. Based on the MIDI information of the input device 110, the performance information output from the storage device 113, and a fluctuation signal output from a fluctuation signal generator 1 described later, a waveform signal having a pitch is output.

The amplitude control device 102 comprises the above-mentioned sound source LSI having a digitally controlled amplifier for giving an amplitude envelope by an amplitude envelope generator while amplifying a musical tone signal. Based on this, amplitude processing such as loudness, envelope, tremolo, and panning is performed.

The frequency characteristic control device 103 is constituted by a digital filter for removing unnecessary harmonic components of the musical tone waveform, and performs frequency characteristic processing based on the MIDI information, performance information, and fluctuation signal. The configuration may be configured as a part of the sound source LSI.

The effect device 104 includes a sound processor and a digital signal processor, and has a function of adding various sound effects such as reverb, chorus, distortion, flanger, phasor, and delay to a tone signal. These processing of the tone signal is performed based on the performance information.

This configuration further includes a digital / analog conversion device 114 and a stereo audio device 115. The digital / analog conversion device 114 converts the tone signal processed by the effect device 104 from digital to analog. , And output as an audio signal from a stereo audio device 115 having an amplifier, a speaker, and the like.

In the above configuration, the waveform signal output from the oscillation device 101 is processed by the amplitude control device 102 and the frequency characteristic control device 103 to become a tone signal. The musical sound waveform is processed by the effect device 104, D / A-converted by the digital / analog converter 114, and then generated as a musical tone by the stereo audio device 115. As described above, each of these devices is controlled by the central processing unit 112, and the status is displayed on the display device 111 so that the user can confirm it. In this configuration, a fluctuation signal generator 1 for generating two types of fluctuation signals is provided, and as shown in FIG. 2, these fluctuation signals are added to the configuration of the amplitude control device 102 (and / or the oscillation device 101). And a monaural tone signal is output as a stereo tone.

FIG. 3 is a block diagram showing a detailed configuration of the fluctuation signal generator 1. As shown in FIG. As shown in FIG. 1, the fluctuation signal generator 1 includes a random number generator 10, a fluctuation signal frequency characteristic controller 11 and a fluctuation signal amplitude controller 12, and these components are configured by a dedicated LSI. (Or may be constituted by the central processing unit and the storage device 113, a fluctuation generating program and a digital filter that operate in these device configurations). The above configuration is related to the need for parameters of distribution characteristics, frequency characteristics, and amplitude characteristics for generation of fluctuation. Therefore, each of these parameters is specified by the central processing unit 112.

The random number generating device 10 generates random numbers having a certain distribution characteristic. In addition to a configuration using a distribution table, a configuration having a random number having a distribution characteristic in a storage device can be considered. The former configuration is used.
FIG. 4 shows a configuration in the case of the present embodiment using a distribution table. As shown in the figure, a uniform random number is generated by the M-sequence noise generator 10a, and a random number having a distribution characteristic is generated by table conversion. In this configuration, the selector 1 that receives a distribution characteristic designation signal from the central processing unit 112 (the signal is determined by the central processing unit 112 based on a parameter given from the input device 110)
By selecting one distribution table from the N types of distribution tables 10c at 0b, table conversion is performed according to the selected distribution table. In this table conversion,
The address on the selected table is designated by the uniformly generated random number, and the data on the table corresponding to the address is generated as a new random number. The M-sequence noise generator 10a is configured to generate noise having a uniform distribution characteristic, but may be another uniform random number generating means.

FIG. 5 is a detailed explanatory diagram of the distribution table 10c. As shown in the figure, the table is developed on the ROM of the storage device 113. In this configuration, as an example, the table has addresses from 0 to 15 and stores data corresponding to these addresses. FIG. The data has values from -3 to 3,
When addresses are uniformly accessed based on uniform random numbers generated by the M-sequence noise generator 10a,
The frequency distribution has distribution characteristics as shown in Table 1 below and FIG.

[0025]

[Table 1]

The distribution characteristics of sounds in the natural world and fluctuation signals of live musical instruments resemble a normal distribution. Those that are not so will be quite similar if the normal distribution curve is easily transformed. Therefore, the types of distribution characteristics used in this configuration are approximated as shown in FIG. FIG. 7A shows a normal distribution curve. FIGS. 7B and 7C show the vertices of the curve in FIG. 7A shifted to the left. Similarly, it may be shifted to the right.

The frequency characteristic control device 11 is constituted by a digital filter, and processes the random number generated by the random number generation device 10 into a frequency specified by the central processing unit 112.

The frequency characteristics of natural world sounds and fluctuation signals of live musical instruments resemble those of a low-pass filter. Therefore, the types of frequency characteristics controlled by this configuration are approximated as shown in FIG. As shown in the figure, the cutoff frequency of the filter is lower in the order of (a), (b) and (c).

Even though there are three types of distribution characteristics of the fluctuation signal and three types of frequency characteristics of the fluctuation signal, there are nine combinations thereof, so that nine types of fluctuation signals can be selected.

The amplitude control device 12 is composed of a digitally controlled amplifier that gives an amplitude envelope by an amplitude envelope generator, and converts the random number processed by the frequency characteristic control device 11 into an amplitude characteristic specified by the central processing unit 112. Process. Here, the amplitude characteristic means a depth (depth) of a fluctuation signal with respect to a musical sound waveform and a change in a temporal amplitude of the fluctuation signal.

As described above, two types of fluctuation signals (for right and left) are generated, and the amplitude control device 102 adds different fluctuation signals to the right and left tone control signals. Similarly, the oscillation device 10 for controlling the pitch
A different fluctuation signal may be added to 1. Alternatively, a fluctuation signal may be added to the above two device configurations. As a result, even if a monaural tone signal is output from the oscillator 101, a stereo signal can be obtained by changing the fluctuation signal given to the right and left sides. Is obtained. Furthermore,
The configuration of the fluctuation signal generator 1 can also be configured by a storage device that records the fluctuation signal in addition to the above configuration.
In that case, by changing the read position, it becomes possible to generate two or more types of fluctuation signals.

The above-described configuration of the present invention is not of a nature incompatible with the configuration of the above-described conventional stereo apparatus. When used in combination with these configurations, a tone with a more natural feeling and a high stereo effect is output. It is possible to do.

The structure of the present invention is not limited to a stereo output having only two types of outputs, but also a stereo output having three or more outputs.
That is, application to surround output is possible. As shown in FIG. 9, this can be achieved by generating fluctuation signals different in number by the number desired to be output and adding these fluctuation signals to a predetermined device.

[0034]

According to the configuration of the present invention described in detail above, a stereo tone can be generated from a monaural tone, so that the storage capacity of waveform data can be reduced when obtaining a stereo tone. Becomes possible. In addition, since a fluctuation signal is added to obtain a stereo musical sound, a more natural stereo feeling can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall circuit configuration when a stereo musical sound generator according to an embodiment of the present invention is used in an electronic musical instrument.

FIG. 2 is a block diagram showing an additional configuration of a fluctuation signal in the present configuration.

FIG. 3 is a block diagram showing a detailed configuration of a fluctuation signal generator.

FIG. 4 is a block diagram of a random number generation device using a distribution table in the case of the present embodiment.

FIG. 5 is a detailed explanatory diagram of a distribution table.

FIG. 6 is a graph showing characteristics of a random number frequency distribution.

FIG. 7 is a graph showing types of distribution characteristics of random number generation frequencies.

FIG. 8 is a graph showing types of frequency characteristics of a fluctuation signal.

FIG. 9 is a block diagram showing another configuration for adding a fluctuation signal.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 fluctuation generator 10 random number generator 10a M-sequence noise generator 10b selector 10c distribution table 11 frequency characteristic controller for fluctuation signal 12 amplitude controller for fluctuation signal 100 bus 101 oscillator 102 amplitude controller 103 frequency characteristic controller for musical sound 104 effect device 110 input device 111 display device 112 central processing unit 113 storage device 114 digital / analog conversion device 115 stereo audio device

Claims (5)

[Claims] 1. A stereo musical sound generating method, wherein two or more musical signals are added to a monaural musical sound to generate two or more musical tones, and the stereo musical sound is generated. 2. A stereo tone generating method according to claim 1, wherein at least one of a distribution characteristic, a frequency characteristic, and an amplitude characteristic necessary for generating a fluctuation is changed to generate two or more types of fluctuation signals. 2. A stereo tone generating method according to claim 1, wherein said fluctuation signals are added to monaural tone. 3. An oscillator used for generating at least a tone signal, an amplitude controller for controlling the amplitude of the tone signal generated thereby, a frequency characteristic controller for controlling the frequency characteristic of the tone signal, and a tone. And a tone output device for outputting a tone.
A fluctuation signal generating device for generating two or more types of fluctuation signals is provided, and these fluctuation signals are added to any one or a plurality of configurations for generating the musical tone, and the monaural musical signal is converted to two or more. A stereo tone generator for producing and outputting a stereo tone. 4. The stereo tone generator according to claim 3, wherein said fluctuation signal generator comprises at least a random number generator and a frequency characteristic controller, and the initial setting of said random number generator is changed to at least two types of said random number generator. 4. The stereo tone generator according to claim 3, wherein a fluctuation signal is generated. 5. The stereo tone generator according to claim 3, wherein said fluctuation signal generator is constituted by a storage device in which the fluctuation signal is recorded, and the readout position is changed to generate two or more types of fluctuation signals. 4. The stereo musical sound generator according to claim 3, wherein: