JPH0573052A - Musical sound modulation device - Google Patents

Abstract

PURPOSE:To generate a musical sound with natural fluctuations by utilizing a fluctuation signal having a power spectrum which varies in power depending upon the frequency. CONSTITUTION:A white noise from a white noise generator 71 is inputted to a 1/f filter 72 and converted here into a 1/f fluctuation signal. The band width of the fluctuation signal outputted by a fluctuation signal generating means 110 is limited by a modulating signal generating means 111 to a frequency low-band part. Further, a linear interpolating circuit 75 interposes an interpolation value between adjacent fluctuation data samples from the fluctuation signal generating means 110 to generate a modulating signal. This modulating signal is multiplied by a multiplier 77 by an amplitude width setting signal from an amplitude operation element and its amplitude is varied. Thus, fluctuations having the most suitable band width and amplitude for the musical sound are generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a musical tone modulator for modulating a musical tone signal generated by a sound source such as an electronic musical instrument.

[0002]

2. Description of the Related Art A typical conventional tone modulating device has a relatively low frequency (for example, several to several tens of H for vibrato applications).
An LFO (low frequency oscillator) that generates a simple repeating waveform of z) (for example, a sine wave or a sawtooth wave) is used as a modulation signal source. In principle, the tone modulation provided by this type of tone modulating device is a simple repetitive variation, and therefore, an artificial and mechanical impression cannot be wiped out.

On the other hand, in another conventional technique, a white noise generator is used as a modulation signal source. Since this kind of musical tone modulator gives a completely irregular variation to the musical tone, it is the opposite of the above-mentioned prior art and cannot give the pleasant variation and fluctuation of natural sound.

In order to remedy the above-mentioned problems of the prior art in the simple poles and irregular poles, noise (for example, with a characteristic that its power (or amplitude) decreases as the fluctuation frequency increases). , 1 / f noise) has been proposed (see Japanese Patent Application No. 2-31515, filed on Feb. 14, 1990).

[0005]

By the way, according to experiments, a tone modulating device using this type of fluctuation generator is
It was effective in reproducing faint sounds. However, there was a problem that it was not possible to obtain sufficient results for musical sounds with slow fluctuations.

The present inventor has found that the reason is the wide bandwidth of the fluctuation signal output from the fluctuation generator. For example, taking the 1 / f fluctuation as an example, the power of the fluctuation frequency (160 Hz) 32 times that of the fluctuation frequency of 5 Hz has a magnitude of 1/32. However, in reality, this size has a much larger effect than 1/32 due to human hearing characteristics,
This is because you can hear it as a mixed sound of faint sounds.

However, in the tone modulating device according to the above-mentioned prior application, although the fluctuation bandwidth and the fluctuation amplitude differ depending on the type of the musical instrument to be played, the fluctuation always has a constant bandwidth and amplitude. However, there is also a problem that the sound is unnatural compared to the musical sound generated from the natural musical instrument.

That is, the natural musical instrument itself has comfortable fluctuations and fluctuations that natural sounds have. For example, the bandwidth and amplitude of fluctuations are different between a wind instrument and a stringed instrument. However, in order to give fluctuations with the same bandwidth and amplitude to the musical sounds corresponding to the wind instrument and the stringed instrument, the musical tone modulated by the musical tone modulator according to the prior application is compared with the musical tone generated from the wind instrument or the stringed instrument itself. It sounds unnatural.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a musical tone modulator capable of generating a musical tone having a more natural fluctuation and having a fluctuation having a bandwidth and an amplitude most suitable for the musical sound. I am trying.

[0010]

A tone modulating device according to the present invention comprises a sound source means for electronically generating a tone signal and a fluctuation signal for generating a fluctuation signal having a power spectrum whose power changes depending on the frequency value. Signal generating means, bandwidth varying means for varying the bandwidth of the fluctuation signal, amplitude varying means for varying the amplitude of the fluctuation signal, fluctuation signals from the fluctuation signal generating means, the bandwidth varying means, A modulation signal forming means for forming a modulated signal by changing its bandwidth and amplitude by the amplitude changing means, and a modulating means for modulating a tone signal generated in the sound source means based on the modulated signal are provided. And

[0011]

According to the present invention, the fluctuation signal generating means generates a fluctuation signal having a power spectrum whose power changes depending on the frequency, and the fluctuation band width and amplitude of this fluctuation signal are variably set by the modulation signal forming means. Then, a modulated signal is formed. Further, the tone signal of the sound source is modulated by the modulating means based on this modulated signal.

Therefore, the optimum fluctuation for the natural musical instrument sound (the fluctuation having the bandwidth and amplitude most suitable for the musical sound)
Is more accurately simulated.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing the overall configuration of an electronic musical instrument in which a musical tone modulating device according to the present invention is incorporated.

In FIG. 1, the electronic musical instrument is roughly divided into a CPU 1 for controlling the entire apparatus, a ROM 2 for storing programs and constants, and an R as a working memory.
AM3, a keyboard 4 as a performance input device, a sound source 5 (sound source means) 5 capable of electronically generating a plurality of (four in FIG. 1) sounds, and a tone signal from the sound source 5 is output to the outside. It includes a sound system 6 and a modulation circuit 7 as a modulation signal source for modulating the musical sound generated by the sound source 5. Then, these respective circuits are connected to each other via a bus 8.

The modulation circuit 7 is provided for each sounding channel of the polyphonic sound source 5 (in FIG. 1, represented by sound sources 0, 1, 2, 3).
1 has a plurality of modulation channels (indicated by modulation circuits 0, 1, 2, 3 in FIG. 1).

The CPU (modulation means) 1 reads the modulation signal from the modulation circuit 7 and controls the sound source 5 according to the value to modulate the tone signal generated by the sound source 5. In this case, the modulation signal is used to modulate the pitch (frequency) of the musical tone, the volume, the timbre, or the sound effect (for example, reverb).

Further, in this embodiment, the bandwidth operator 11 for varying the bandwidth of the fluctuation signal is connected to the bus 8 via the A / D converter 12, and the amplitude operator 13 for varying the amplitude is A / D. It is connected to the bus 8 via the D converter 14. These operators 11 and 13 are, for example, formed in a dial shape and attached to a board surface of an electronic musical instrument, and are operated by a player so as to correspond to a natural musical instrument to be calculated.

Here, the bandwidth operator 11 outputs a bandwidth setting signal as a signal for varying the bandwidth of the fluctuation signal, and the amplitude operator 13 sets the amplitude as a signal for varying the amplitude of the fluctuation signal. Output a signal.

FIG. 2 shows the structure of the modulation circuit 7 for one channel. In each modulation circuit channel, a white noise generator 71 generates pseudo white noise having a spectrum of equal power.

FIG. 3 shows a configuration example of the white noise generator 71. Here, the flip-flop chains 81a to 81
Pseudo white noise (pseudo random number sequence) is formed by the combination of n and the exclusive OR elements 82a and 82b.

Returning to FIG. 2, the white noise from the white noise generator 71 is input to the 1 / f filter 72, where it is converted into a fluctuation signal having a 1 / f fluctuation characteristic. FIG. 4 shows a configuration example of the 1 / f filter 72.

As shown in the figure, the 1 / f filter 72 is composed of four adder elements 91 to 94, two delay elements 95 and 96, and four multiplier elements 97 to 100. The multipliers in the multiplication elements 97 to 100 are respectively set to [63/6
It is known that a fluctuation signal close to 1 / f can be obtained by selecting 4], [-15/16], [3/4], or [-1/4]. The fluctuation filter is not limited to the 1 / f filter as in this embodiment, but a fluctuation signal may be generated using a filter having other fluctuation characteristics (for example, 1 / f ² , 1 / f ³ ). You can

Returning to FIG. 2, the white noise generator 7 of the modulation circuit
The 1 and 1 / f filter 72 is a fluctuation signal generating means 11
Configures 0. It should be noted that the fluctuation bandwidth of the fluctuation signal output from the fluctuation signal generating means 110 is considerably wide.

Therefore, in the present embodiment, in order to limit this wide bandwidth to the low frequency part, the modulation signal forming means 111.
Are using. The modulation signal forming means 111 is realized by a data latch 73, a 1/16 frequency divider 74 and a linear interpolation circuit 75. The 1/16 frequency divider 74 divides the modulated basic clock by 1/16 to generate a white noise generator 7 signal.
It is supplied as a clock to the 1/1 / f filter 72 and the data latch 73. The data latch 73 is 1 / f
The digital data of the fluctuation signal from the filter 72 is taken in as a sample.

On the other hand, the clock from the modulation basic clock circuit 76 is directly input to the linear interpolation circuit 75. The modulation basic clock circuit 76 is provided for the bandwidth operator 11
The clock period can be varied by the bandwidth setting signal from. As a result, the linear interpolation circuit 75, which is the main element of the modulation signal forming means 111, operates at 16 times the operating frequency of the fluctuation signal generating means 110.

The linear interpolation circuit 75 is a fluctuation signal generating means 1
At least one or more (here, 15 according to 1/16 division) interpolation values are inserted between adjacent fluctuation data samples from 10 to form a modulation signal (shown as output x). Then, this modulated signal is multiplied by the amplitude setting signal from the amplitude operator 13 in the multiplier 77, and the amplitude is varied.

A configuration example of the linear interpolation circuit 75 is shown in FIG.
In FIG. 5, the linear interpolation circuit 75 includes a subtractor 121, a 4-bit shift circuit 122, an adder 123, and an output latch 124. The subtractor 121 of the linear interpolation circuit 75 receives the new fluctuation data sample X (i + 1) from the 1 / f filter 72 and the old fluctuation data sample X (i) from the data latch 73. The data samples X (i + 1) and X (i) are adjacent data samples in the fluctuation signal.

The subtractor 121 takes the difference (X (i + 1) -X (i)) between the adjacent data samples and outputs it to the 4-bit shift circuit 122. 4-bit shift circuit 12
2 multiplies this difference by 1/16 to obtain the data (X (i + 1)-
X (i)) / 16 is formed and output to the adder 123.
The adder 123 adds the data (X (i + 1) -X (i)) / 16 from the 4-bit shift circuit 122 to the data from the output latch 124 which operates with the modulation basic clock, and outputs it as an output x.

Therefore, the modulation signal x, which is the output of the output latch 124 (that is, the output of the linear interpolation circuit 75 and the output of the modulation circuit), is synchronized with the modulation basic clock at X (i), X (i). +1/16 (difference), X (i) + 2 /
16 (difference), ..., X (i) +15/16 (difference), X
(I + 1) (where the difference is the difference between adjacent fluctuation data samples X (i) and X (i + 1)) to form a linear interpolation data string in which the fluctuation band is limited to the low frequency band. ..

In operation, the CPU 1 reads the value of the modulation signal x of the modulation circuit 7 and controls the corresponding tone generation channel of the sound source 5 based on the value. When the key is pressed, the CPU
1 gives a clear signal to the modulation circuit 7 (channel) assigned to the key depression to initialize the modulation circuit 7. In FIG. 2, the clear signal is the white noise generator 71, 1 / f
Filter 72, data latch 73 and linear interpolation circuit 7
Input to 5.

Next, a flow chart of the tone modulation operation by the CPU 1 will be described with reference to FIGS.

First, the CPU 1 executes key scanning in step S1, and when a key depression is detected (steps S2 and S3), the tone generation channel of the sound source 5 and the channel of the modulation circuit 7 are assigned to the key depression. The assigned modulation circuit 7 is initialized to generate a sounding channel (steps S4 to S11).

More specifically, in step S4, the key code for key depression is set in the A register, and the channel counter n is set to 0.
While moving from 0 to 3 in the sky channel (C
Cn = 0) is found (steps S5 to S8).

When an empty channel is found, the key code A for key depression is stored in the channel register CCn (step S9), and the corresponding modulation circuit (channel) n.
To clear the modulation circuit channel n (step S10) and give a sounding instruction to the sound source (channel) n (step S11).

The process for the channel being sounded is shown in FIG. The CPU 1 initializes the channel counter n (n = 0) in step S12, and then, in step S1.
Channel being pronounced at 3 (CCn is 0, that is, "empty")
If not, the frequency data f (cent proportional expression) corresponding to the key code CCn of the channel is read out in step S14, and the modulation data x (range of 0 to 1) is handled from the modulation circuit channel n. Read), and further step S1
The basic frequency data f is modulated according to the following equation (1) using the modulation data x read in 6 and the depth depth.

F = f + (x−1 / 2) × depth (1) According to the equation (1), the frequency data is centered on the fundamental frequency (scale frequency f ₀ ) and is set to the value of the modulated signal x. Accordingly f ₀ − (1
/ 2) A value that fluctuates in the range from depth to f ₀ + (1/2) depth.

Then, in step S17, the modulated frequency data f is sent to the sound source channel n. afterwards,
In steps S18 and S19, the above processing is executed for all channels.

As a result, a tone signal whose frequency (pitch) fluctuates depending on the modulation signal x from the corresponding modulation circuit channel n is generated from the sound source channel n being sounded. Here, the modulated signal x has a fluctuation frequency characteristic in which the fluctuation bandwidth is limited to the low frequency band, so that a more natural and realistic pitch fluctuation is added to the musical sound than in the past.

In the case of this embodiment, the modulated signal x is formed by variably setting the fluctuation bandwidth and amplitude of the fluctuation signal. Therefore, the fluctuation having the bandwidth and the amplitude most suitable for the natural musical instrument is simulated more accurately.

At the start of sound generation (step S11), the tone generator channel starts to generate a musical sound at the fundamental frequency (scale frequency f ₀ ).

Next, the CPU 1 scans the key (step S1).
When the key release is detected in (step S2, step S3), the key release processing routine shown in FIG. 8 is executed.
In the key release processing routine, first, in step S20, the key code of the key release is set in the A register, and while the channel counter n is moved from 0, the channel register CCn having the same key code as the key release within the range of 0 to 3 is set. (Step S21 to step S24), the channel register CCn is returned to the empty state "0" (step S25), and the corresponding sound source channel n is muted (step S26).

Various modifications are possible within the scope of the present invention. For example, at least a part of the modulation circuit and the sound source is a program (software) and C for executing the program.
You may implement with PU. Further, the modulation signal may be used for modulation of other elements (for example, volume, tone color, sound) of the musical sound other than the pitch (pitch).

Further, other methods of calculating the modulated parameters are possible. For example, the highest frequency data fmax and the lowest frequency data fmin are prepared for each key code, and these data are read in step S14,
In step S16, the modulated signal x may be used to obtain the modulated frequency data by the arithmetic expression f = fmin + x (fmax-fmin).

[0044]

According to the present invention, a fluctuation signal having a power spectrum whose power changes depending on the frequency is generated, and the fluctuation bandwidth and amplitude of this fluctuation signal are variably set to form a modulation signal. Moreover, since the tone signal of the sound source is modulated based on this modulation signal, it is possible to give fluctuations having a bandwidth and amplitude most suitable for the natural musical instrument sound.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of an embodiment of an electronic musical instrument to which a musical tone modulator of the invention is applied.

FIG. 2 is a configuration diagram of a modulation circuit of the same embodiment.

FIG. 3 is a configuration diagram of a white noise generator of the same embodiment.

FIG. 4 is a configuration diagram of a 1 / f filter according to the first embodiment.

FIG. 5 is a configuration diagram of a linear interpolation circuit of the same embodiment.

FIG. 6 is a flowchart showing a part of the operation of the CPU of the same embodiment.

FIG. 7 is a flowchart showing a part of the operation of the CPU of the same embodiment.

FIG. 8 is a flowchart showing a part of the operation of the CPU of the same embodiment.

[Explanation of symbols]

 1 CPU (modulating means) 2 ROM 3 RAM 4 keyboard 5 sound source (sound source means) 6 sound system 7 modulation circuit 11 bandwidth operator (bandwidth varying means) 13 amplitude operator (amplitude varying means) 71 white noise generator 72 1 / f filter 73 Data latch 74 1/16 frequency divider 75 Linear interpolation circuit 76 Modulation basic clock circuit 77 Multiplier 81a-81n Flip-flop chain 82a, 82b Exclusive OR element 91-94 Addition element 95, 96 Delay element 97-100 Multiplier element 110 Fluctuation signal generating means 111 Modulation signal forming means 121 Attenuator 122 4-bit shift circuit 123 Adder 124 Output latch

Claims (1)

[Claims] 1. A sound source means for electronically generating a tone signal, a fluctuation signal generating means for generating a fluctuation signal having a power spectrum whose power changes depending on a frequency value, and a bandwidth of the fluctuation signal. Bandwidth varying means for varying, amplitude varying means for varying the amplitude of the fluctuation signal, a fluctuation signal from the fluctuation signal generating means, the bandwidth and amplitude are varied by the bandwidth varying means and the amplitude varying means. And a modulation signal forming means for forming a modulation signal, and a modulation means for modulating a tone signal generated in the sound source means based on the modulation signal.